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This file contains information about GCC releases which has been generated
automatically from the online release notes. It covers releases of GCC
(and the former EGCS project) since EGCS 1.0, on the line of development
that led to GCC 3. For information on GCC 2.8.1 and older releases of GCC 2,
see ONEWS.
======================================================================
http://gcc.gnu.org/gcc-4.4/index.html
GCC 4.4 Release Series
October 15, 2009
The [1]GNU project and the GCC developers are pleased to announce the
release of GCC 4.4.3.
This release is a bug-fix release, containing fixes for regressions in
GCC 4.4.1 relative to previous releases of GCC.
Release History
GCC 4.4.3
January 21, 2010 ([2]changes)
GCC 4.4.2
October 15, 2009 ([3]changes)
GCC 4.4.1
July 22, 2009 ([4]changes)
GCC 4.4.0
April 21, 2009 ([5]changes)
References and Acknowledgements
GCC used to stand for the GNU C Compiler, but since the compiler
supports several other languages aside from C, it now stands for the
GNU Compiler Collection.
A list of [6]successful builds is updated as new information becomes
available.
The GCC developers would like to thank the numerous people that have
contributed new features, improvements, bug fixes, and other changes as
well as test results to GCC. This [7]amazing group of volunteers is
what makes GCC successful.
For additional information about GCC please refer to the [8]GCC project
web site or contact the [9]GCC development mailing list.
To obtain GCC please use [10]our mirror sites or [11]our SVN server.
Please send FSF & GNU inquiries & questions to [12]gnu@gnu.org. There
are also [13]other ways to contact the FSF.
These pages are maintained by [14]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [15]GCC manuals. If that fails, the
[16]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [17]gcc@gnu.org or [18]gcc@gcc.gnu.org.
All of our lists have [19]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2010-01-21 [20]Valid XHTML 1.0
References
1. http://www.gnu.org/
2. http://gcc.gnu.org/gcc-4.4/changes.html
3. http://gcc.gnu.org/gcc-4.4/changes.html
4. http://gcc.gnu.org/gcc-4.4/changes.html
5. http://gcc.gnu.org/gcc-4.4/changes.html
6. http://gcc.gnu.org/gcc-4.4/buildstat.html
7. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
8. http://gcc.gnu.org/index.html
9. mailto:gcc@gcc.gnu.org
10. http://gcc.gnu.org/mirrors.html
11. http://gcc.gnu.org/svn.html
12. mailto:gnu@gnu.org
13. http://www.gnu.org/home.html#ContactInfo
14. http://gcc.gnu.org/about.html
15. http://gcc.gnu.org/onlinedocs/
16. mailto:gcc-help@gcc.gnu.org
17. mailto:gcc@gnu.org
18. mailto:gcc@gcc.gnu.org
19. http://gcc.gnu.org/lists.html
20. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.4/changes.html
GCC 4.4 Release Series
Changes, New Features, and Fixes
The latest release in the 4.4 release series is [1]GCC 4.4.3.
Caveats
* __builtin_stdarg_start has been completely removed from GCC.
Support for <varargs.h> had been deprecated since GCC 4.0. Use
__builtin_va_start as a replacement.
* Some of the errors issued by the C++ front end that could be
downgraded to warnings in previous releases by using -fpermissive
are now warnings by default. They can be converted into errors by
using -pedantic-errors.
* Use of the cpp assertion extension will now emit a warning when
-Wdeprecated or -pedantic is used. This extension has been
deprecated for many years, but never warned about.
* Packed bit-fields of type char were not properly bit-packed on many
targets prior to GCC 4.4. On these targets, the fix in GCC 4.4
causes an ABI change. For example there is no longer a 4-bit
padding between field a and b in this structure:
struct foo
{
char a:4;
char b:8;
} __attribute__ ((packed));
There is a new warning to help identify fields that are affected:
foo.c:5: note: Offset of packed bit-field 'b' has changed in GCC 4.4
The warning can be disabled with -Wno-packed-bitfield-compat.
* On ARM EABI targets, the C++ mangling of the va_list type has been
changed to conform to the current revision of the EABI. This does
not affect the libstdc++ library included with GCC.
* The SCOUNT and POS bits of the MIPS DSP control register are now
treated as global. Previous versions of GCC treated these fields as
call-clobbered instead.
* The MIPS port no longer recognizes the h asm constraint. It was
necessary to remove this constraint in order to avoid generating
unpredictable code sequences.
One of the main uses of the h constraint was to extract the high
part of a multiplication on 64-bit targets. For example:
asm ("dmultu\t%1,%2" : "=h" (result) : "r" (x), "r" (y));
You can now achieve the same effect using 128-bit types:
typedef unsigned int uint128_t __attribute__((mode(TI)));
result = ((uint128_t) x * y) >> 64;
The second sequence is better in many ways. For example, if x and y
are constants, the compiler can perform the multiplication at
compile time. If x and y are not constants, the compiler can
schedule the runtime multiplication better than it can schedule an
asm statement.
* Support for a number of older systems and recently unmaintained or
untested target ports of GCC has been declared obsolete in GCC 4.4.
Unless there is activity to revive them, the next release of GCC
will have their sources permanently removed.
The following ports for individual systems on particular
architectures have been obsoleted:
+ Generic a.out on IA32 and m68k (i[34567]86-*-aout*,
m68k-*-aout*)
+ Generic COFF on ARM, H8300, IA32, m68k and SH (arm-*-coff*,
armel-*-coff*, h8300-*-*, i[34567]86-*-coff*, m68k-*-coff*,
sh-*-*). This does not affect other more specific targets
using the COFF object format on those architectures, or the
more specific H8300 and SH targets (h8300-*-rtems*,
h8300-*-elf*, sh-*-elf*, sh-*-symbianelf*, sh-*-linux*,
sh-*-netbsdelf*, sh-*-rtems*, sh-wrs-vxworks).
+ 2BSD on PDP-11 (pdp11-*-bsd)
+ AIX 4.1 and 4.2 on PowerPC (rs6000-ibm-aix4.[12]*,
powerpc-ibm-aix4.[12]*)
+ Tuning support for Itanium1 (Merced) variants. Note that code
tuned for Itanium2 should also run correctly on Itanium1.
* The protoize and unprotoize utilities have been obsoleted and will
be removed in GCC 4.5. These utilities have not been installed by
default since GCC 3.0.
* Support has been removed for all the [2]configurations obsoleted in
GCC 4.3.
* Unknown -Wno-* options are now silently ignored by GCC if no other
diagnostics are issued. If other diagnostics are issued, then GCC
warns about the unknown options.
* More information on porting to GCC 4.4 from previous versions of
GCC can be found in the [3]porting guide for this release.
General Optimizer Improvements
* A new command-line switch -findirect-inlining has been added. When
turned on it allows the inliner to also inline indirect calls that
are discovered to have known targets at compile time thanks to
previous inlining.
* A new command-line switch -ftree-switch-conversion has been added.
This new pass turns simple initializations of scalar variables in
switch statements into initializations from a static array, given
that all the values are known at compile time and the ratio between
the new array size and the original switch branches does not exceed
the parameter --param switch-conversion-max-branch-ratio (default
is eight).
* A new command-line switch -ftree-builtin-call-dce has been added.
This optimization eliminates unnecessary calls to certain builtin
functions when the return value is not used, in cases where the
calls can not be eliminated entirely because the function may set
errno. This optimization is on by default at -O2 and above.
* A new command-line switch -fconserve-stack directs the compiler to
minimize stack usage even if it makes the generated code slower.
This affects inlining decisions.
* When the assembler supports it, the compiler will now emit unwind
information using assembler .cfi directives. This makes it possible
to use such directives in inline assembler code. The new option
-fno-dwarf2-cfi-asm directs the compiler to not use .cfi
directives.
* The [4]Graphite branch has been merged. This merge has brought in a
new framework for loop optimizations based on a polyhedral
intermediate representation. These optimizations apply to all the
languages supported by GCC. The following new code transformations
are available in GCC 4.4:
+ -floop-interchange performs loop interchange transformations
on loops. Interchanging two nested loops switches the inner
and outer loops. For example, given a loop like:
DO J = 1, M
DO I = 1, N
A(J, I) = A(J, I) * C
ENDDO
ENDDO
loop interchange will transform the loop as if the user had
written:
DO I = 1, N
DO J = 1, M
A(J, I) = A(J, I) * C
ENDDO
ENDDO
which can be beneficial when N is larger than the caches,
because in Fortran, the elements of an array are stored in
memory contiguously by column, and the original loop iterates
over rows, potentially creating at each access a cache miss.
+ -floop-strip-mine performs loop strip mining transformations
on loops. Strip mining splits a loop into two nested loops.
The outer loop has strides equal to the strip size and the
inner loop has strides of the original loop within a strip.
For example, given a loop like:
DO I = 1, N
A(I) = A(I) + C
ENDDO
loop strip mining will transform the loop as if the user had
written:
DO II = 1, N, 4
DO I = II, min (II + 3, N)
A(I) = A(I) + C
ENDDO
ENDDO
+ -floop-block performs loop blocking transformations on loops.
Blocking strip mines each loop in the loop nest such that the
memory accesses of the element loops fit inside caches. For
example, given a loop like:
DO I = 1, N
DO J = 1, M
A(J, I) = B(I) + C(J)
ENDDO
ENDDO
loop blocking will transform the loop as if the user had
written:
DO II = 1, N, 64
DO JJ = 1, M, 64
DO I = II, min (II + 63, N)
DO J = JJ, min (JJ + 63, M)
A(J, I) = B(I) + C(J)
ENDDO
ENDDO
ENDDO
ENDDO
which can be beneficial when M is larger than the caches,
because the innermost loop will iterate over a smaller amount
of data that can be kept in the caches.
* A new register allocator has replaced the old one. It is called
integrated register allocator (IRA) because coalescing, register
live range splitting, and hard register preferencing are done
on-the-fly during coloring. It also has better integration with the
reload pass. IRA is a regional register allocator which uses modern
Chaitin-Briggs coloring instead of Chow's priority coloring used in
the old register allocator. More info about IRA internals and
options can be found in the GCC manuals.
* A new instruction scheduler and software pipeliner, based on the
selective scheduling approach, has been added. The new pass
performs instruction unification, register renaming, substitution
through register copies, and speculation during scheduling. The
software pipeliner is able to pipeline non-countable loops. The new
pass is targeted at scheduling-eager in-order platforms. In GCC 4.4
it is available for the Intel Itanium platform working by default
as the second scheduling pass (after register allocation) at the
-O3 optimization level.
* When using -fprofile-generate with a multi-threaded program, the
profile counts may be slightly wrong due to race conditions. The
new -fprofile-correction option directs the compiler to apply
heuristics to smooth out the inconsistencies. By default the
compiler will give an error message when it finds an inconsistent
profile.
* The new -fprofile-dir=PATH option permits setting the directory
where profile data files are stored when using -fprofile-generate
and friends, and the directory used when reading profile data files
using -fprofile-use and friends.
New warning options
* The new -Wframe-larger-than=NUMBER option directs GCC to emit a
warning if any stack frame is larger than NUMBER bytes. This may be
used to help ensure that code fits within a limited amount of stack
space.
* The new -Wno-mudflap option disables warnings about constructs
which can not be instrumented when using -fmudflap.
New Languages and Language specific improvements
* Version 3.0 of the [5]OpenMP specification is now supported for the
C, C++, and Fortran compilers.
* New character data types, per [6]TR 19769: New character types in
C, are now supported for the C compiler in -std=gnu99 mode, as
__CHAR16_TYPE__ and __CHAR32_TYPE__, and for the C++ compiler in
-std=c++0x and -std=gnu++0x modes, as char16_t and char32_t too.
C family
* A new optimize attribute was added to allow programmers to change
the optimization level and particular optimization options for an
individual function. You can also change the optimization options
via the GCC optimize pragma for functions defined after the pragma.
The GCC push_options pragma and the GCC pop_options pragma allow
you temporarily save and restore the options used. The GCC
reset_options pragma restores the options to what was specified on
the command line.
* Uninitialized warnings do not require enabling optimization
anymore, that is, -Wuninitialized can be used together with -O0.
Nonetheless, the warnings given by -Wuninitialized will probably be
more accurate if optimization is enabled.
* -Wparentheses now warns about expressions such as (!x | y) and (!x
& y). Using explicit parentheses, such as in ((!x) | y), silences
this warning.
* -Wsequence-point now warns within if, while,do while and for
conditions, and within for begin/end expressions.
* A new option -dU is available to dump definitions of preprocessor
macros that are tested or expanded.
C++
* [7]Improved experimental support for the upcoming ISO C++ standard,
C++0x. Including support for auto, inline namespaces, generalized
initializer lists, defaulted and deleted functions, new character
types, and scoped enums.
* Those errors that may be downgraded to warnings to build legacy
code now mention -fpermissive when -fdiagnostics-show-option is
enabled.
* -Wconversion now warns if the result of a static_cast to enumeral
type is unspecified because the value is outside the range of the
enumeral type.
* -Wuninitialized now warns if a non-static reference or non-static
const member appears in a class without constructors.
* G++ now properly implements value-initialization, so objects with
an initializer of () and an implicitly defined default constructor
will be zero-initialized before the default constructor is called.
Runtime Library (libstdc++)
* [8]Improved experimental support for the upcoming ISO C++ standard,
C++0x, including:
+ Support for <chrono>, <condition_variable>, <cstdatomic>,
<forward_list>, <initializer_list>, <mutex>, <ratio>,
<system_error>, and <thread>.
+ unique_ptr, <algorithm> additions, exception propagation, and
support for the new character types in <string> and <limits>.
+ Existing facilities now exploit initializer lists, defaulted
and deleted functions, and the newly implemented core C++0x
features.
+ Some standard containers are more efficient together with
stateful allocators, i.e., no allocator is constructed on the
fly at element construction time.
* Experimental support for non-standard pointer types in containers.
* The long standing libstdc++/30928 has been fixed for targets
running glibc 2.10 or later.
* As usual, many small and larger bug fixes, in particular quite a
few corner cases in <locale>.
Fortran
* GNU Fortran now employs libcpp directly instead of using cc1 as an
external preprocessor. The [9]-cpp option was added to allow manual
invocation of the preprocessor without relying on filename
extensions.
* The [10]-Warray-temporaries option warns about array temporaries
generated by the compiler, as an aid to optimization.
* The [11]-fcheck-array-temporaries option has been added, printing a
notification at run time, when an array temporary had to be created
for an function argument. Contrary to -Warray-temporaries the
warning is only printed if the array is noncontiguous.
* Improved generation of DWARF debugging symbols
* If using an intrinsic not part of the selected standard (via -std=
and -fall-intrinsics) gfortran will now treat it as if this
procedure were declared EXTERNAL and try to link to a user-supplied
procedure. -Wintrinsics-std will warn whenever this happens. The
now-useless option -Wnonstd-intrinsic was removed.
* The flag -falign-commons has been added to control the alignment of
variables in COMMON blocks, which is enabled by default in line
with previous GCC version. Using -fno-align-commons one can force
commons to be contiguous in memory as required by the Fortran
standard, however, this slows down the memory access. The option
-Walign-commons, which is enabled by default, warns when padding
bytes were added for alignment. The proper solution is to sort the
common objects by decreasing storage size, which avoids the
alignment problems.
* Fortran 2003 support has been extended:
+ Wide characters (ISO 10646, UCS-4, kind=4) and UTF-8 I/O is
now supported (except internal reads from/writes to wide
strings). [12]-fbackslash now supports also \unnnn and
\Unnnnnnnn to enter Unicode characters.
+ Asynchronous I/O (implemented as synchronous I/O) and the
decimal=, size=, sign=, pad=, blank=, and delim= specifiers
are now supported in I/O statements.
+ Support for Fortran 2003 structure constructors and for array
constructor with typespec has been added.
+ Procedure Pointers (but not yet as component in derived types
and as function results) are now supported.
+ Abstract types, type extension, and type-bound procedures
(both PROCEDURE and GENERIC but not as operators). Note: As
CLASS/polymorphyic types are not implemented, type-bound
procedures with PASS accept as non-standard extension TYPE
arguments.
* Fortran 2008 support has been added:
+ The -std=f2008 option and support for the file extensions
.f2008 and .F2008 has been added.
+ The g0 format descriptor is now supported.
+ The Fortran 2008 mathematical intrinsics ASINH, ACOSH, ATANH,
ERF, ERFC, GAMMA, LOG_GAMMA, BESSEL_*, HYPOT, and ERFC_SCALED
are now available (some of them existed as GNU extension
before). Note: The hyperbolic functions are not yet supporting
complex arguments and the three- argument version of BESSEL_*N
is not available.
+ The bit intrinsics LEADZ and TRAILZ have been added.
Java (GCJ)
Ada
* The Ada runtime now supports multilibs on many platforms including
x86_64, SPARC and PowerPC. Their build is enabled by default.
New Targets and Target Specific Improvements
ARM
* GCC now supports optimizing for the Cortex-A9, Cortex-R4 and
Cortex-R4F processors and has many other improvements to
optimization for ARM processors.
* GCC now supports the VFPv3 variant with 16 double-precision
registers with -mfpu=vfpv3-d16. The option -mfpu=vfp3 has been
renamed to -mfpu=vfpv3.
* GCC now supports the -mfix-cortex-m3-ldrd option to work around an
erratum on Cortex-M3 processors.
* GCC now supports the __sync_* atomic operations for ARM EABI
GNU/Linux.
* The section anchors optimization is now enabled by default when
optimizing for ARM.
* GCC now uses a new EABI-compatible profiling interface for EABI
targets. This requires a function __gnu_mcount_nc, which is
provided by GNU libc versions 2.8 and later.
AVR
* The -mno-tablejump option has been deprecated because it has the
same effect as the -fno-jump-tables option.
* Added support for these new AVR devices:
+ ATA6289
+ ATtiny13A
+ ATtiny87
+ ATtiny167
+ ATtiny327
+ ATmega8C1
+ ATmega16C1
+ ATmega32C1
+ ATmega8M1
+ ATmega16M1
+ ATmega32M1
+ ATmega32U4
+ ATmega16HVB
+ ATmega4HVD
+ ATmega8HVD
+ ATmega64C1
+ ATmega64M1
+ ATmega16U4
+ ATmega32U6
+ ATmega128RFA1
+ AT90PWM81
+ AT90SCR100
+ M3000F
+ M3000S
+ M3001B
IA-32/x86-64
* Support for Intel AES built-in functions and code generation is
available via -maes.
* Support for Intel PCLMUL built-in function and code generation is
available via -mpclmul.
* Support for Intel AVX built-in functions and code generation is
available via -mavx.
* Automatically align the stack for local variables with alignment
requirement.
* GCC can now utilize the SVML library for vectorizing calls to a set
of C99 functions if -mveclibabi=svml is specified and you link to
an SVML ABI compatible library.
* On x86-64, the ABI has been changed in the following cases to
conform to the x86-64 ABI:
+ Passing/returning structures with flexible array member:
struct foo
{
int i;
int flex[];
};
+ Passing/returning structures with complex float member:
struct foo
{
int i;
__complex__ float f;
};
+ Passing/returning unions with long double member:
union foo
{
int x;
long double ld;
};
Code built with previous versions of GCC that uses any of these is
not compatible with code built with GCC 4.4.0 or later.
* A new target attribute was added to allow programmers to change the
target options like -msse2 or -march=k8 for an individual function.
You can also change the target options via the GCC target pragma
for functions defined after the pragma.
* GCC can now be configured with options --with-arch-32,
--with-arch-64, --with-cpu-32, --with-cpu-64, --with-tune-32 and
--with-tune-64 to control the default optimization separately for
32-bit and 64-bit modes.
IA-32/IA64
* Support for __float128 (TFmode) IEEE quad type and corresponding
TCmode IEEE complex quad type is available via the soft-fp library
on IA-32/IA64 targets. This includes basic arithmetic operations
(addition, subtraction, negation, multiplication and division) on
__float128 real and TCmode complex values, the full set of IEEE
comparisons between __float128 values, conversions to and from
float, double and long double floating point types, as well as
conversions to and from signed or unsigned integer, signed or
unsigned long integer and signed or unsigned quad (TImode, IA64
only) integer types. Additionally, all operations generate the full
set of IEEE exceptions and support the full set of IEEE rounding
modes.
M68K/ColdFire
* GCC now supports instruction scheduling for ColdFire V1, V3 and V4
processors. (Scheduling support for ColdFire V2 processors was
added in GCC 4.3.)
* GCC now supports the -mxgot option to support programs requiring
many GOT entries on ColdFire.
* The m68k-*-linux-gnu target now builds multilibs by default.
MIPS
* MIPS Technologies have extended the original MIPS SVR4 ABI to
include support for procedure linkage tables (PLTs) and copy
relocations. These extensions allow GNU/Linux executables to use a
significantly more efficient code model than the one defined by the
original ABI.
GCC support for this code model is available via a new command-line
option, -mplt. There is also a new configure-time option,
--with-mips-plt, to make -mplt the default.
The new code model requires support from the assembler, the linker,
and the runtime C library. This support is available in binutils
2.19 and GLIBC 2.9.
* GCC can now generate MIPS16 code for 32-bit GNU/Linux executables
and 32-bit GNU/Linux shared libraries. This feature requires GNU
binutils 2.19 or above.
* Support for RMI's XLR processor is now available through the
-march=xlr and -mtune=xlr options.
* 64-bit targets can now perform 128-bit multiplications inline,
instead of relying on a libgcc function.
* Native GNU/Linux toolchains now support -march=native and
-mtune=native, which select the host processor.
* GCC now supports the R10K, R12K, R14K and R16K processors. The
canonical -march= and -mtune= names for these processors are
r10000, r12000, r14000 and r16000 respectively.
* GCC can now work around the side effects of speculative execution
on R10K processors. Please see the documentation of the
-mr10k-cache-barrier option for details.
* Support for the MIPS64 Release 2 instruction set has been added.
The option -march=mips64r2 enables generation of these
instructions.
* GCC now supports Cavium Networks' Octeon processor. This support is
available through the -march=octeon and -mtune=octeon options.
* GCC now supports STMicroelectronics' Loongson 2E/2F processors. The
canonical -march= and -mtune= names for these processors are
loongson2e and loongson2f.
picochip
Picochip is a 16-bit processor. A typical picoChip contains over 250
small cores, each with small amounts of memory. There are three
processor variants (STAN, MEM and CTRL) with different instruction sets
and memory configurations and they can be chosen using the -mae option.
This port is intended to be a "C" only port.
Power Architecture and PowerPC
* GCC now supports the e300c2, e300c3 and e500mc processors.
* GCC now supports Xilinx processors with a single-precision FPU.
* Decimal floating point is now supported for e500 processors.
S/390, zSeries and System z9/z10
* Support for the IBM System z10 EC/BC processor has been added. When
using the -march=z10 option, the compiler will generate code making
use of instructions provided by the General-Instruction-Extension
Facility and the Execute-Extension Facility.
VxWorks
* GCC now supports the thread-local storage mechanism used on
VxWorks.
Xtensa
* GCC now supports thread-local storage (TLS) for Xtensa processor
configurations that include the Thread Pointer option. TLS also
requires support from the assembler and linker; this support is
provided in the GNU binutils beginning with version 2.19.
Documentation improvements
Other significant improvements
GCC 4.4.1
This is the [13]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.4.1 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
GCC 4.4.2
This is the [14]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.4.2 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
GCC 4.4.3
This is the [15]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.4.3 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
Please send FSF & GNU inquiries & questions to [16]gnu@gnu.org. There
are also [17]other ways to contact the FSF.
These pages are maintained by [18]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [19]GCC manuals. If that fails, the
[20]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [21]gcc@gnu.org or [22]gcc@gcc.gnu.org.
All of our lists have [23]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2010-01-21 [24]Valid XHTML 1.0
References
1. http://gcc.gnu.org/gcc-4.4/changes.html#4.4.3
2. http://gcc.gnu.org/gcc-4.3/changes.html#obsoleted
3. http://gcc.gnu.org/gcc-4.4/porting_to.html
4. http://gcc.gnu.org/wiki/Graphite
5. http://openmp.org/wp/openmp-specifications/
6. http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1040.pdf
7. http://gcc.gnu.org/gcc-4.4/cxx0x_status.html
8. http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#id476343
9. http://gcc.gnu.org/onlinedocs/gfortran/Preprocessing-Options.html
10. http://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWarray-temporaries_007d-125
11. http://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcheck-array-temporaries_007d-221
12. http://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bbackslash_007d-34
13. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.1
14. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.2
15. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.3
16. mailto:gnu@gnu.org
17. http://www.gnu.org/home.html#ContactInfo
18. http://gcc.gnu.org/about.html
19. http://gcc.gnu.org/onlinedocs/
20. mailto:gcc-help@gcc.gnu.org
21. mailto:gcc@gnu.org
22. mailto:gcc@gcc.gnu.org
23. http://gcc.gnu.org/lists.html
24. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.3/index.html
GCC 4.3 Release Series
January 24, 2009
The [1]GNU project and the GCC developers are pleased to announce the
release of GCC 4.3.4.
This release is a bug-fix release, containing fixes for regressions in
GCC 4.3.3 relative to previous releases of GCC.
Release History
GCC 4.3.4
August 4, 2009 ([2]changes)
GCC 4.3.3
January 24, 2009 ([3]changes)
GCC 4.3.2
August 27, 2008 ([4]changes)
GCC 4.3.1
June 6, 2008 ([5]changes)
GCC 4.3.0
March 5, 2008 ([6]changes)
References and Acknowledgements
GCC used to stand for the GNU C Compiler, but since the compiler
supports several other languages aside from C, it now stands for the
GNU Compiler Collection.
A list of [7]successful builds is updated as new information becomes
available.
The GCC developers would like to thank the numerous people that have
contributed new features, improvements, bug fixes, and other changes as
well as test results to GCC. This [8]amazing group of volunteers is
what makes GCC successful.
For additional information about GCC please refer to the [9]GCC project
web site or contact the [10]GCC development mailing list.
To obtain GCC please use [11]our mirror sites or [12]our SVN server.
Please send FSF & GNU inquiries & questions to [13]gnu@gnu.org. There
are also [14]other ways to contact the FSF.
These pages are maintained by [15]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [16]GCC manuals. If that fails, the
[17]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [18]gcc@gnu.org or [19]gcc@gcc.gnu.org.
All of our lists have [20]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2009-10-15 [21]Valid XHTML 1.0
References
1. http://www.gnu.org/
2. http://gcc.gnu.org/gcc-4.3/changes.html
3. http://gcc.gnu.org/gcc-4.3/changes.html
4. http://gcc.gnu.org/gcc-4.3/changes.html
5. http://gcc.gnu.org/gcc-4.3/changes.html
6. http://gcc.gnu.org/gcc-4.3/changes.html
7. http://gcc.gnu.org/gcc-4.3/buildstat.html
8. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
9. http://gcc.gnu.org/index.html
10. mailto:gcc@gcc.gnu.org
11. http://gcc.gnu.org/mirrors.html
12. http://gcc.gnu.org/svn.html
13. mailto:gnu@gnu.org
14. http://www.gnu.org/home.html#ContactInfo
15. http://gcc.gnu.org/about.html
16. http://gcc.gnu.org/onlinedocs/
17. mailto:gcc-help@gcc.gnu.org
18. mailto:gcc@gnu.org
19. mailto:gcc@gcc.gnu.org
20. http://gcc.gnu.org/lists.html
21. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.3/changes.html
GCC 4.3 Release Series
Changes, New Features, and Fixes
The latest release in the 4.3 release series is [1]GCC 4.3.4.
Caveats
* GCC requires the [2]GMP and [3]MPFR libraries for building all the
various front-end languages it supports. See the [4]prerequisites
page for version requirements.
* ColdFire targets now treat long double as having the same format as
double. In earlier versions of GCC, they used the 68881 long double
format instead.
* The m68k-uclinux target now uses the same calling conventions as
m68k-linux-gnu. You can select the original calling conventions by
configuring for m68k-uclinuxoldabi instead. Note that
m68k-uclinuxoldabi also retains the original 80-bit long double on
ColdFire targets.
* The -fforce-mem option has been removed because it has had no
effect in the last few GCC releases.
* The i386 -msvr3-shlib option has been removed since it is no longer
used.
* Fastcall for i386 has been changed not to pass aggregate arguments
in registers, following Microsoft compilers.
* Support for the AOF assembler has been removed from the ARM back
end; this affects only the targets arm-semi-aof and armel-semi-aof,
which are no longer recognized. We removed these targets without a
deprecation period because we discovered that they have been
unusable since GCC 4.0.0.
* Support for the TMS320C3x/C4x processor (targets c4x-* and tic4x-*)
has been removed. This support had been deprecated since GCC 4.0.0.
* Support for a number of older systems and recently unmaintained or
untested target ports of GCC has been declared obsolete in GCC 4.3.
Unless there is activity to revive them, the next release of GCC
will have their sources permanently removed.
All GCC ports for the following processor architectures have been
declared obsolete:
+ Morpho MT (mt-*)
The following aliases for processor architectures have been
declared obsolete. Users should use the indicated generic target
names instead, with compile-time options such as -mcpu or
configure-time options such as --with-cpu to control the
configuration more precisely.
+ strongarm*-*-*, ep9312*-*-*, xscale*-*-* (use arm*-*-*
instead).
+ parisc*-*-* (use hppa*-*-* instead).
+ m680[012]0-*-* (use m68k-*-* instead).
All GCC ports for the following operating systems have been
declared obsolete:
+ BeOS (*-*-beos*)
+ kaOS (*-*-kaos*)
+ GNU/Linux using the a.out object format (*-*-linux*aout*)
+ GNU/Linux using version 1 of the GNU C Library
(*-*-linux*libc1*)
+ Solaris versions before Solaris 7 (*-*-solaris2.[0-6],
*-*-solaris2.[0-6].*)
+ Miscellaneous System V (*-*-sysv*)
+ WindISS (*-*-windiss*)
Also, those for some individual systems on particular architectures
have been obsoleted:
+ UNICOS/mk on DEC Alpha (alpha*-*-unicosmk*)
+ CRIS with a.out object format (cris-*-aout)
+ BSD 4.3 on PA-RISC (hppa1.1-*-bsd*)
+ OSF/1 on PA-RISC (hppa1.1-*-osf*)
+ PRO on PA-RISC (hppa1.1-*-pro*)
+ Sequent PTX on IA32 (i[34567]86-sequent-ptx4*,
i[34567]86-sequent-sysv4*)
+ SCO Open Server 5 on IA32 (i[34567]86-*-sco3.2v5*)
+ UWIN on IA32 (i[34567]86-*-uwin*) (support for UWIN as a host
was previously [5]removed in 2001, leaving only the support
for UWIN as a target now being deprecated)
+ ChorusOS on PowerPC (powerpc-*-chorusos*)
+ All VAX configurations apart from NetBSD and OpenBSD
(vax-*-bsd*, vax-*-sysv*, vax-*-ultrix*)
* The [6]-Wconversion option has been modified. Its purpose now is to
warn for implicit conversions that may alter a value. This new
behavior is available for both C and C++. Warnings about
conversions between signed and unsigned integers can be disabled by
using -Wno-sign-conversion. In C++, they are disabled by default
unless -Wsign-conversion is explicitly requested. The old behavior
of -Wconversion, that is, warn for prototypes causing a type
conversion that is different from what would happen to the same
argument in the absence of a prototype, has been moved to a new
option -Wtraditional-conversion, which is only available for C.
* The -m386, -m486, -mpentium and -mpentiumpro tuning options have
been removed because they were deprecated for more than 3 GCC major
releases. Use -mtune=i386, -mtune=i486, -mtune=pentium or
-mtune=pentiumpro as a replacement.
* The -funsafe-math-optimizations option now automatically turns on
-fno-trapping-math in addition to -fno-signed-zeros, as it enables
reassociation and thus may introduce or remove traps.
* The -ftree-vectorize option is now on by default under -O3. In
order to generate code for a SIMD extension, it has to be enabled
as well: use -maltivec for PowerPC platforms and -msse/-msse2 for
i?86 and x86_64.
* More information on porting to GCC 4.3 from previous versions of
GCC can be found in the [7]porting guide for this release.
General Optimizer Improvements
* The GCC middle-end has been integrated with the [8]MPFR library.
This allows GCC to evaluate and replace at compile-time calls to
built-in math functions having constant arguments with their
mathematically equivalent results. In making use of [9]MPFR, GCC
can generate correct results regardless of the math library
implementation or floating point precision of the host platform.
This also allows GCC to generate identical results regardless of
whether one compiles in native or cross-compile configurations to a
particular target. The following built-in functions take advantage
of this new capability: acos, acosh, asin, asinh, atan2, atan,
atanh, cbrt, cos, cosh, drem, erf, erfc, exp10, exp2, exp, expm1,
fdim, fma, fmax, fmin, gamma_r, hypot, j0, j1, jn, lgamma_r, log10,
log1p, log2, log, pow10, pow, remainder, remquo, sin, sincos, sinh,
tan, tanh, tgamma, y0, y1 and yn. The float and long double
variants of these functions (e.g. sinf and sinl) are also handled.
The sqrt and cabs functions with constant arguments were already
optimized in prior GCC releases. Now they also use [10]MPFR.
* A new forward propagation pass on RTL was added. The new pass
replaces several slower transformations, resulting in compile-time
improvements as well as better code generation in some cases.
* A new command-line switch -frecord-gcc-switches has been added to
GCC, although it is only enabled for some targets. The switch
causes the command line that was used to invoke the compiler to be
recorded into the object file that is being created. The exact
format of this recording is target and binary file format
dependent, but it usually takes the form of a note section
containing ASCII text. The switch is related to the -fverbose-asm
switch, but that one only records the information in the assembler
output file as comments, so the information never reaches the
object file.
* The inliner heuristic is now aware of stack frame consumption. New
command-line parameters --param large-stack-frame and --param
large-stack-frame-growth can be used to limit stack frame size
growth caused by inlining.
* During feedback directed optimizations, the expected block size the
memcpy, memset and bzero functions operate on is discovered and for
cases of commonly used small sizes, specialized inline code is
generated.
* __builtin_expect no longer requires its argument to be a compile
time constant.
* Interprocedural optimization was reorganized to work on functions
in SSA form. This enables more precise and cheaper dataflow
analysis and makes writing interprocedural optimizations easier.
The following improvements have been implemented on top of this
framework:
+ Pre-inline optimization: Selected local optimization passes
are run before the inliner (and other interprocedural passes)
are executed. This significantly improves the accuracy of code
growth estimates used by the inliner and reduces the overall
memory footprint for large compilation units.
+ Early inlining (a simple bottom-up inliner pass inlining only
functions whose body is smaller than the expected call
overhead) is now executed with the early optimization passes,
thus inlining already optimized function bodies into an
unoptimized function that is subsequently optimized by early
optimizers. This enables the compiler to quickly eliminate
abstraction penalty in C++ programs.
+ Interprocedural constant propagation now operate on SSA form
increasing accuracy of the analysis.
* A new internal representation for GIMPLE statements has been
contributed, resulting in compile-time memory savings.
* The vectorizer was enhanced to support vectorization of outer
loops, intra-iteration parallelism (loop-aware SLP), vectorization
of strided accesses and loops with multiple data-types. Run-time
dependency testing using loop versioning was added. The cost model,
turned on by -fvect-cost-model, was developed.
New Languages and Language specific improvements
* We have added new command-line options
-finstrument-functions-exclude-function-list and
-finstrument-functions-exclude-file-list. They provide more control
over which functions are annotated by the -finstrument-functions
option.
C family
* Implicit conversions between generic vector types are now only
permitted when the two vectors in question have the same number of
elements and compatible element types. (Note that the restriction
involves compatible element types, not implicitly-convertible
element types: thus, a vector type with element type int may not be
implicitly converted to a vector type with element type unsigned
int.) This restriction, which is in line with specifications for
SIMD architectures such as AltiVec, may be relaxed using the flag
-flax-vector-conversions. This flag is intended only as a
compatibility measure and should not be used for new code.
* -Warray-bounds has been added and is now enabled by default for
-Wall . It produces warnings for array subscripts that can be
determined at compile time to be always out of bounds.
-Wno-array-bounds will disable the warning.
* The constructor and destructor function attributes now accept
optional priority arguments which control the order in which the
constructor and destructor functions are run.
* New [11]command-line options -Wtype-limits,
-Wold-style-declaration, -Wmissing-parameter-type, -Wempty-body,
-Wclobbered and -Wignored-qualifiers have been added for finer
control of the diverse warnings enabled by -Wextra.
* A new function attribute alloc_size has been added to mark up
malloc style functions. For constant sized allocations this can be
used to find out the size of the returned pointer using the
__builtin_object_size() function for buffer overflow checking and
similar. This supplements the already built-in malloc and calloc
constant size handling.
* Integer constants written in binary are now supported as a GCC
extension. They consist of a prefix 0b or 0B, followed by a
sequence of 0 and 1 digits.
* A new predefined macro __COUNTER__ has been added. It expands to
sequential integral values starting from 0. In conjunction with the
## operator, this provides a convenient means to generate unique
identifiers.
* A new command-line option -fdirectives-only has been added. It
enables a special preprocessing mode which improves the performance
of applications like distcc and ccache.
* Fixed-point data types and operators have been added. They are
based on Chapter 4 of the Embedded-C specification (n1169.pdf).
Currently, only MIPS targets are supported.
* Decimal floating-point arithmetic based on draft ISO/IEC TR 24732,
N1241, is now supported as a GCC extension to C for targets
i[34567]86-*-linux-gnu, powerpc*-*-linux-gnu, s390*-ibm-linux-gnu,
and x86_64-*-linux-gnu. The feature introduces new data types
_Decimal32, _Decimal64, and _Decimal128 with constant suffixes DF,
DD, and DL.
C++
* [12]Experimental support for the upcoming ISO C++ standard, C++0x.
* -Wc++0x-compat has been added and is now enabled by default for
-Wall. It produces warnings for constructs whose meaning differs
between ISO C++ 1998 and C++0x.
* The -Wparentheses option now works for C++ as it does for C. It
warns if parentheses are omitted when operators with confusing
precedence are nested. It also warns about ambiguous else
statements. Since -Wparentheses is enabled by -Wall, this may cause
additional warnings with existing C++ code which uses -Wall. These
new warnings may be disabled by using -Wall -Wno-parentheses.
* The -Wmissing-declarations now works for C++ as it does for C.
* The -fvisibility-ms-compat flag was added, to make it easier to
port larger projects using shared libraries from Microsoft's Visual
Studio to ELF and Mach-O systems.
* C++ attribute handling has been overhauled for template arguments
(ie dependent types). In particular, __attribute__((aligned(T)));
works for C++ types.
Runtime Library (libstdc++)
* [13]Experimental support for the upcoming ISO C++ standard, C++0x.
* Support for TR1 mathematical special functions and regular
expressions. ([14]Implementation status of TR1)
* Default what implementations give more elaborate exception strings
for bad_cast, bad_typeid, bad_exception, and bad_alloc.
* Header dependencies have been streamlined, reducing unnecessary
includes and pre-processed bloat.
* Variadic template implementations of items in <tuple> and
<functional>.
* An experimental [15]parallel mode has been added. This is a
parallel implementation of many C++ Standard library algorithms,
like std::accumulate, std::for_each, std::transform, or std::sort,
to give but four examples. These algorithms can be substituted for
the normal (sequential) libstdc++ algorithms on a piecemeal basis,
or all existing algorithms can be transformed via the
-D_GLIBCXX_PARALLEL macro.
* Debug mode versions of classes in <unordered_set> and
<unordered_map>.
* Formal deprecation of <ext/hash_set> and <ext/hash_map>, which are
now <backward/hash_set> and <backward/hash_map>. This code:
#include <ext/hash_set>
__gnu_cxx::hash_set<int> s;
Can be transformed (in order of preference) to:
#include <tr1/unordered_set>
std::tr1::unordered_set<int> s;
or
#include <backward/hash_set>
__gnu_cxx::hash_set<int> s;
Similar transformations apply to __gnu_cxx::hash_map,
__gnu_cxx::hash_multimap, __gnu_cxx::hash_set,
__gnu_cxx::hash_multiset.
Fortran
* Due to the fact that the [16]GMP and [17]MPFR libraries are
required for all languages, Fortran is no longer special in this
regard and is available by default.
* The [18]-fexternal-blas option has been added, which generates
calls to BLAS routines for intrinsic matrix operations such as
matmul rather than using the built-in algorithms.
* Support to give a backtrace (compiler flag -fbacktrace or
environment variable GFORTRAN_ERROR_BACKTRACE; on glibc systems
only) or a core dump (-fdump-core, GFORTRAN_ERROR_DUMPCORE) when a
run-time error occured.
* GNU Fortran now defines __GFORTRAN__ when it runs the C
preprocessor (CPP).
* The [19]-finit-local-zero, -finit-real, -finit-integer,
-finit-character, and -finit-logical options have been added, which
can be used to initialize local variables.
* The intrinsic procedures [20]GAMMA and [21]LGAMMA have been added,
which calculate the Gamma function and its logarithm. Use EXTERNAL
gamma if you want to use your own gamma function.
* GNU Fortran now regards the backslash character as literal (as
required by the Fortran 2003 standard); using [22]-fbackslash GNU
Fortran interprets backslashes as C-style escape characters.
* The [23]interpretation of binary, octal and hexadecimal (BOZ)
literal constants has been changed. Before they were always
interpreted as integer; now they are bit-wise transferred as
argument of INT, REAL, DBLE and CMPLX as required by the Fortran
2003 standard, and for real and complex variables in DATA
statements or when directly assigned to real and complex variables.
Everywhere else and especially in expressions they are still
regarded as integer constants.
* Fortran 2003 support has been extended:
+ Intrinsic statements IMPORT, PROTECTED, VALUE and VOLATILE
+ Pointer intent
+ Intrinsic module ISO_ENV_FORTRAN
+ Interoperability with C (ISO C Bindings)
+ ABSTRACT INTERFACES and PROCEDURE statements (without POINTER
attribute)
+ Fortran 2003 BOZ
Java (GCJ)
* gcj now uses the Eclipse Java compiler for its Java parsing needs.
This enables the use of all 1.5 language features, and fixes most
existing front end bugs.
* libgcj now supports all 1.5 language features which require runtime
support: foreach, enum, annotations, generics, and auto-boxing.
* We've made many changes to the tools shipped with gcj.
+ The old jv-scan tool has been removed. This tool never really
worked properly. There is no replacement.
+ gcjh has been rewritten. Some of its more obscure options no
longer work, but are still recognized in an attempt at
compatibility. gjavah is a new program with similar
functionality but different command-line options.
+ grmic and grmiregistry have been rewritten. grmid has been
added.
+ gjar replaces the old fastjar.
+ gjarsigner (used for signing jars), gkeytool (used for key
management), gorbd (for CORBA), gserialver (computes
serialization UIDs), and gtnameserv (also for CORBA) are now
installed.
* The ability to dump the contents of the java run time heap to a
file for off-line analysis has been added. The heap dumps may be
analyzed with the new gc-analyze tool. They may be generated on
out-of-memory conditions or on demand and are controlled by the new
run time class gnu.gcj.util.GCInfo.
* java.util.TimeZone can now read files from /usr/share/zoneinfo to
provide correct, updated, timezone information. This means that
packagers no longer have to update libgcj when a time zone change
is published.
New Targets and Target Specific Improvements
IA-32/x86-64
* Tuning for Intel Core 2 processors is available via -mtune=core2
and -march=core2.
* Tuning for AMD Geode processors is available via -mtune=geode and
-march=geode.
* Code generation of block move (memcpy) and block set (memset) was
rewritten. GCC can now pick the best algorithm (loop, unrolled
loop, instruction with rep prefix or a library call) based on the
size of the block being copied and the CPU being optimized for. A
new option -minline-stringops-dynamically has been added. With this
option string operations of unknown size are expanded such that
small blocks are copied by in-line code, while for large blocks a
library call is used. This results in faster code than
-minline-all-stringops when the library implementation is capable
of using cache hierarchy hints. The heuristic choosing the
particular algorithm can be overwritten via -mstringop-strategy.
Newly also memset of values different from 0 is inlined.
* GCC no longer places the cld instruction before string operations.
Both i386 and x86-64 ABI documents mandate the direction flag to be
clear at the entry of a function. It is now invalid to set the flag
in asm statement without reseting it afterward.
* Support for SSSE3 built-in functions and code generation are
available via -mssse3.
* Support for SSE4.1 built-in functions and code generation are
available via -msse4.1.
* Support for SSE4.2 built-in functions and code generation are
available via -msse4.2.
* Both SSE4.1 and SSE4.2 support can be enabled via -msse4.
* A new set of options -mpc32, -mpc64 and -mpc80 have been added to
allow explicit control of x87 floating point precision.
* Support for __float128 (TFmode) IEEE quad type and corresponding
TCmode IEEE complex quad type is available via the soft-fp library
on x86_64 targets. This includes basic arithmetic operations
(addition, subtraction, negation, multiplication and division) on
__float128 real and TCmode complex values, the full set of IEEE
comparisons between __float128 values, conversions to and from
float, double and long double floating point types, as well as
conversions to and from signed or unsigned integer, signed or
unsigned long integer and signed or unsigned quad (TImode) integer
types. Additionally, all operations generate the full set of IEEE
exceptions and support the full set of IEEE rounding modes.
* GCC can now utilize the ACML library for vectorizing calls to a set
of C99 functions on x86_64 if -mveclibabi=acml is specified and you
link to an ACML ABI compatible library.
ARM
* Compiler and Library support for Thumb-2 and the ARMv7 architecture
has been added.
CRIS
New features
* Compiler and Library support for the CRIS v32 architecture, as
found in Axis Communications ETRAX FS and ARTPEC-3 chips, has been
added.
Configuration changes
* The cris-*-elf target now includes support for CRIS v32, including
libraries, through the -march=v32 option.
* A new crisv32-*-elf target defaults to generate code for CRIS v32.
* A new crisv32-*-linux* target defaults to generate code for CRIS
v32.
* The cris-*-aout target has been obsoleted.
Improved support for built-in functions
* GCC can now use the lz and swapwbr instructions to implement the
__builtin_clz, __builtin_ctz and __builtin_ffs family of functions.
* __builtin_bswap32 is now implemented using the swapwb instruction,
when available.
m68k and ColdFire
New features
* Support for several new ColdFire processors has been added. You can
generate code for them using the new -mcpu option.
* All targets now support ColdFire processors.
* m68k-uclinux targets have improved support for C++ constructors and
destructors, and for shared libraries.
* It is now possible to set breakpoints on the first or last line of
a function, even if there are no statements on that line.
Optimizations
* Support for sibling calls has been added.
* More use is now made of the ColdFire mov3q instruction.
* __builtin_clz is now implemented using the ff1 ColdFire
instruction, when available.
* GCC now honors the -m68010 option. 68010 code now uses clr rather
than move to zero volatile memory.
* 68020 targets and above can now use symbol(index.size*scale)
addresses for indexed array accesses. Earlier compilers would
always load the symbol into a base register first.
Configuration changes
* All m68k and ColdFire targets now allow the default processor to be
set at configure time using --with-cpu.
* A --with-arch configuration option has been added. This option
allows you to restrict a target to ColdFire or non-ColdFire
processors.
Preprocessor macros
* An __mcfv*__ macro is now defined for all ColdFire targets.
(Earlier versions of GCC only defined __mcfv4e__.)
* __mcf_cpu_*, __mcf_family_* and __mcffpu__ macros have been added.
* All targets now define __mc68010 and __mc68010__ when generating
68010 code.
Command-line changes
* New command-line options -march, -mcpu, -mtune and -mhard-float
have been added. These options apply to both m68k and ColdFire
targets.
* -mno-short, -mno-bitfield and -mno-rtd are now accepted as negative
versions of -mshort, etc.
* -fforce-addr has been removed. It is now ignored by the compiler.
Other improvements
* ColdFire targets now try to maintain a 4-byte-aligned stack where
possible.
* m68k-uclinux targets now try to avoid situations that lead to the
load-time error: BINFMT_FLAT: reloc outside program.
MIPS
Changes to existing configurations
* libffi and libjava now support all three GNU/Linux ABIs: o32, n32
and n64. Every GNU/Linux configuration now builds these libraries
by default.
* GNU/Linux configurations now generate -mno-shared code unless
overridden by -fpic, -fPIC, -fpie or -fPIE.
* mipsisa32*-linux-gnu configurations now generate hard-float code by
default, just like other mipsisa32* and mips*-linux-gnu
configurations. You can build a soft-float version of any
mips*-linux-gnu configuration by passing --with-float=soft to
configure.
* mips-wrs-vxworks now supports run-time processes (RTPs).
Changes to existing command-line options
* The -march and -mtune options no longer accept 24k as a processor
name. Please use 24kc, 24kf2_1 or 24kf1_1 instead.
* The -march and -mtune options now accept 24kf2_1, 24kef2_1 and
34kf2_1 as synonyms for 24kf, 24kef and 34kf respectively. The
options also accept 24kf1_1, 24kef1_1 and 34kf1_1 as synonyms for
24kx, 24kex and 34kx.
New configurations
GCC now supports the following configurations:
* mipsisa32r2*-linux-gnu*, which generates MIPS32 revision 2 code by
default. Earlier releases also recognized this configuration, but
they treated it in the same way as mipsisa32*-linux-gnu*. Note that
you can customize any mips*-linux-gnu* configuration to a
particular ISA or processor by passing an appropriate --with-arch
option to configure.
* mipsisa*-sde-elf*, which provides compatibility with MIPS
Technologies' SDE toolchains. The configuration uses the SDE
libraries by default, but you can use it like other newlib-based
ELF configurations by passing --with-newlib to configure. It is the
only configuration besides mips64vr*-elf* to build MIPS16 as well
as non-MIPS16 libraries.
* mipsisa*-elfoabi*, which is similar to the general mipsisa*-elf*
configuration, but uses the o32 and o64 ABIs instead of the 32-bit
and 64-bit forms of the EABI.
New processors and application-specific extensions
* Support for the SmartMIPS ASE is available through the new
-msmartmips option.
* Support for revision 2 of the DSP ASE is available through the new
-mdspr2 option. A new preprocessor macro called __mips_dsp_rev
indicates the revision of the ASE in use.
* Support for the 4KS and 74K families of processors is available
through the -march and -mtune options.
Improved support for built-in functions
* GCC can now use load-linked, store-conditional and sync
instructions to implement atomic built-in functions such as
__sync_fetch_and_add. The memory reference must be 4 bytes wide for
32-bit targets and either 4 or 8 bytes wide for 64-bit targets.
* GCC can now use the clz and dclz instructions to implement the
__builtin_ctz and __builtin_ffs families of functions.
* There is a new __builtin___clear_cache function for flushing the
instruction cache. GCC expands this function inline on MIPS32
revision 2 targets, otherwise it calls the function specified by
-mcache-flush-func.
MIPS16 improvements
* GCC can now compile objects that contain a mixture of MIPS16 and
non-MIPS16 code. There are two new attributes, mips16 and nomips16,
for specifying which mode a function should use.
* A new option called -minterlink-mips16 makes non-MIPS16 code
link-compatible with MIPS16 code.
* After many bug fixes, the long-standing MIPS16 -mhard-float support
should now work fairly reliably.
* GCC can now use the MIPS16e save and restore instructions.
* -fsection-anchors now works in MIPS16 mode. MIPS16 code compiled
with -G0 -fsection-anchors is often smaller than code compiled with
-G8. However, please note that you must usually compile all objects
in your application with the same -G option; see the documentation
of -G for details.
* A new option called-mcode-readable specifies which instructions are
allowed to load from the code segment. -mcode-readable=yes is the
default and says that any instruction may load from the code
segment. The other alternatives are -mcode-readable=pcrel, which
says that only PC-relative MIPS16 instructions may load from the
code segment, and -mcode-readable=no, which says that no
instruction may do so. Please see the documentation for more
details, including example uses.
Small-data improvements
There are three new options for controlling small data:
* -mno-extern-sdata, which disables small-data accesses for
externally-defined variables. Code compiled with -Gn
-mno-extern-sdata will be link-compatible with any -G setting
between -G0 and -Gn inclusive.
* -mno-local-sdata, which disables the use of small-data sections for
data that is not externally visible. This option can be a useful
way of reducing small-data usage in less performance-critical parts
of an application.
* -mno-gpopt, which disables the use of the $gp register while still
honoring the -G limit when placing externally-visible data. This
option implies -mno-extern-sdata and -mno-local-sdata and it can be
useful in situations where $gp does not necessarily hold the
expected value.
Miscellaneous improvements
* There is a new option called -mbranch-cost for tweaking the
perceived cost of branches.
* If GCC is configured to use a version of GAS that supports the
.gnu_attribute directive, it will use that directive to record
certain properties of the output code. .gnu_attribute is new to GAS
2.18.
* There are two new function attributes, near and far, for overriding
the command-line setting of -mlong-calls on a function-by-function
basis.
* -mfp64, which previously required a 64-bit target, now works with
MIPS32 revision 2 targets as well. The mipsisa*-elfoabi* and
mipsisa*-sde-elf* configurations provide suitable library support.
* GCC now recognizes the -mdmx and -mmt options and passes them down
to the assembler. It does nothing else with the options at present.
SPU (Synergistic Processor Unit) of the Cell Broadband Engine Architecture
(BEA)
* Support has been added for this new architecture.
RS6000 (POWER/PowerPC)
* Support for the PowerPC 750CL paired-single instructions has been
added with a new powerpc-*-linux*paired* target configuration. It
is enabled by an associated -mpaired option and can be accessed
using new built-in functions.
* Support for auto-detecting architecture and system configuration to
auto-select processor optimization tuning.
* Support for VMX on AIX 5.3 has been added.
* Support for AIX Version 6.1 has been added.
S/390, zSeries and System z9
* Support for the IBM System z9 EC/BC processor (z9 GA3) has been
added. When using the -march=z9-ec option, the compiler will
generate code making use of instructions provided by the decimal
floating point facility and the floating point conversion facility
(pfpo). Besides the instructions used to implement decimal floating
point operations these facilities also contain instructions to move
between general purpose and floating point registers and to modify
and copy the sign-bit of floating point values.
* When the -march=z9-ec option is used the new
-mhard-dfp/-mno-hard-dfp options can be used to specify whether the
decimal floating point hardware instructions will be used or not.
If none of them is given the hardware support is enabled by
default.
* The -mstack-guard option can now be omitted when using stack
checking via -mstack-size in order to let GCC choose a sensible
stack guard value according to the frame size of each function.
* Various changes to improve performance of generated code have been
implemented, including:
+ The condition code set by an add logical with carry
instruction is now available for overflow checks like: a + b +
carry < b.
+ The test data class instruction is now used to implement
sign-bit and infinity checks of binary and decimal floating
point numbers.
Xtensa
* Stack unwinding for exception handling now uses by default a
specialized version of DWARF unwinding. This is not
binary-compatible with the setjmp/longjmp (sjlj) unwinding used for
Xtensa with previous versions of GCC.
* For Xtensa processors that include the Conditional Store option,
the built-in functions for atomic memory access are now implemented
using S32C1I instructions.
* If the Xtensa NSA option is available, GCC will use it to implement
the __builtin_ctz and __builtin_clz functions.
Documentation improvements
* Existing libstdc++ documentation has been edited and restructured
into a single DocBook XML manual. The results can be viewed online
[24]here.
Other significant improvements
* The compiler's --help command-line option has been extended so that
it now takes an optional set of arguments. These arguments restrict
the information displayed to specific classes of command-line
options, and possibly only a subset of those options. It is also
now possible to replace the descriptive text associated with each
displayed option with an indication of its current value, or for
binary options, whether it has been enabled or disabled.
Here are some examples. The following will display all the options
controlling warning messages:
--help=warnings
Whereas this will display all the undocumented, target specific
options:
--help=target,undocumented
This sequence of commands will display the binary optimizations
that are enabled by -O3:
gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts
gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts
diff /tmp/O2-opts /tmp/O3-opts | grep enabled
* The configure options --with-pkgversion and --with-bugurl have been
added. These allow distributors of GCC to include a
distributor-specific string in manuals and --version output and to
specify the URL for reporting bugs in their versions of GCC.
GCC 4.3.1
This is the [25]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.3.1 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
Target Specific Changes
IA-32/x86-64
ABI changes
* Starting with GCC 4.3.1, decimal floating point variables are
aligned to their natural boundaries when they are passed on the
stack for i386.
Command-line changes
* Starting with GCC 4.3.1, the -mcld option has been added to
automatically generate a cld instruction in the prologue of
functions that use string instructions. This option is used for
backward compatibility on some operating systems and can be enabled
by default for 32-bit x86 targets by configuring GCC with the
--enable-cld configure option.
GCC 4.3.2
This is the [26]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.3.2 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
GCC 4.3.3
This is the [27]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.3.3 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
GCC 4.3.4
This is the [28]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.3.4 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
Please send FSF & GNU inquiries & questions to [29]gnu@gnu.org. There
are also [30]other ways to contact the FSF.
These pages are maintained by [31]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [32]GCC manuals. If that fails, the
[33]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [34]gcc@gnu.org or [35]gcc@gcc.gnu.org.
All of our lists have [36]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2009-08-13 [37]Valid XHTML 1.0
References
1. http://gcc.gnu.org/gcc-4.3/changes.html#4.3.4
2. http://gmplib.org/
3. http://www.mpfr.org/
4. http://gcc.gnu.org/install/prerequisites.html
5. http://gcc.gnu.org/ml/gcc-announce/2001/msg00000.html
6. http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options
7. http://gcc.gnu.org/gcc-4.3/porting_to.html
8. http://www.mpfr.org/
9. http://www.mpfr.org/
10. http://www.mpfr.org/
11. http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
12. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html
13. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html
14. http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt01ch01.html#m anual.intro.status.standard.tr1
15. http://gcc.gnu.org/onlinedocs/libstdc++/manual/parallel_mode.html
16. http://gmplib.org/
17. http://www.mpfr.org/
18. http://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#Code-Gen-Options
19. http://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfinit-local-zero_007d-167
20. http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/GAMMA.html
21. http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/LGAMMA.html
22. http://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html
23. http://gcc.gnu.org/onlinedocs/gfortran/BOZ-literal-constants.html
24. http://gcc.gnu.org/onlinedocs/libstdc++/
25. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.1
26. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.2
27. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.3
28. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.4
29. mailto:gnu@gnu.org
30. http://www.gnu.org/home.html#ContactInfo
31. http://gcc.gnu.org/about.html
32. http://gcc.gnu.org/onlinedocs/
33. mailto:gcc-help@gcc.gnu.org
34. mailto:gcc@gnu.org
35. mailto:gcc@gcc.gnu.org
36. http://gcc.gnu.org/lists.html
37. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.2/index.html
GCC 4.2 Release Series
May 19, 2008
The [1]GNU project and the GCC developers are pleased to announce the
release of GCC 4.2.4.
This release is a bug-fix release, containing fixes for regressions in
GCC 4.2.3 relative to previous releases of GCC.
Release History
GCC 4.2.4
May 19, 2008 ([2]changes)
GCC 4.2.3
February 1, 2008 ([3]changes)
GCC 4.2.2
October 7, 2007 ([4]changes)
GCC 4.2.1
July 18, 2007 ([5]changes)
GCC 4.2.0
May 13, 2007 ([6]changes)
References and Acknowledgements
GCC used to stand for the GNU C Compiler, but since the compiler
supports several other languages aside from C, it now stands for the
GNU Compiler Collection.
A list of [7]successful builds is updated as new information becomes
available.
The GCC developers would like to thank the numerous people that have
contributed new features, improvements, bug fixes, and other changes as
well as test results to GCC. This [8]amazing group of volunteers is
what makes GCC successful.
For additional information about GCC please refer to the [9]GCC project
web site or contact the [10]GCC development mailing list.
To obtain GCC please use [11]our mirror sites or [12]our SVN server.
Please send FSF & GNU inquiries & questions to [13]gnu@gnu.org. There
are also [14]other ways to contact the FSF.
These pages are maintained by [15]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [16]GCC manuals. If that fails, the
[17]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [18]gcc@gnu.org or [19]gcc@gcc.gnu.org.
All of our lists have [20]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2008-10-04 [21]Valid XHTML 1.0
References
1. http://www.gnu.org/
2. http://gcc.gnu.org/gcc-4.2/changes.html
3. http://gcc.gnu.org/gcc-4.2/changes.html
4. http://gcc.gnu.org/gcc-4.2/changes.html
5. http://gcc.gnu.org/gcc-4.2/changes.html
6. http://gcc.gnu.org/gcc-4.2/changes.html
7. http://gcc.gnu.org/gcc-4.2/buildstat.html
8. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
9. http://gcc.gnu.org/index.html
10. mailto:gcc@gcc.gnu.org
11. http://gcc.gnu.org/mirrors.html
12. http://gcc.gnu.org/svn.html
13. mailto:gnu@gnu.org
14. http://www.gnu.org/home.html#ContactInfo
15. http://gcc.gnu.org/about.html
16. http://gcc.gnu.org/onlinedocs/
17. mailto:gcc-help@gcc.gnu.org
18. mailto:gcc@gnu.org
19. mailto:gcc@gcc.gnu.org
20. http://gcc.gnu.org/lists.html
21. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.2/changes.html
GCC 4.2 Release Series
Changes, New Features, and Fixes
Caveats
* GCC no longer accepts the -fshared-data option. This option has had
no effect in any GCC 4 release; the targets to which the option
used to apply had been removed before GCC 4.0.
General Optimizer Improvements
* New command-line options specify the possible relationships among
parameters and between parameters and global data. For example,
-fargument-noalias-anything specifies that arguments do not alias
any other storage.
Each language will automatically use whatever option is required by
the language standard. You should not need to use these options
yourself.
New Languages and Language specific improvements
* [1]OpenMP is now supported for the C, C++ and Fortran compilers.
* New command-line options -fstrict-overflow and -Wstrict-overflow
have been added. -fstrict-overflow tells the compiler that it may
assume that the program follows the strict signed overflow
semantics permitted for the language: for C and C++ this means that
the compiler may assume that signed overflow does not occur. For
example, a loop like
for (i = 1; i > 0; i *= 2)
is presumably intended to continue looping until i overflows. With
-fstrict-overflow, the compiler may assume that signed overflow
will not occur, and transform this into an infinite loop.
-fstrict-overflow is turned on by default at -O2, and may be
disabled via -fno-strict-overflow. The -Wstrict-overflow option may
be used to warn about cases where the compiler assumes that signed
overflow will not occur. It takes five different levels:
-Wstrict-overflow=1 to 5. See the [2]documentation for details.
-Wstrict-overflow=1 is enabled by -Wall.
* The new command-line option -fno-toplevel-reorder directs GCC to
emit top-level functions, variables, and asm statements in the same
order that they appear in the input file. This is intended to
support existing code which relies on a particular ordering (for
example, code which uses top-level asm statements to switch
sections). For new code, it is generally better to use function and
variable attributes. The -fno-toplevel-reorder option may be used
for most cases which currently use -fno-unit-at-a-time. The
-fno-unit-at-a-time option will be removed in some future version
of GCC. If you know of a case which requires -fno-unit-at-a-time
which is not fixed by -fno-toplevel-reorder, please open a bug
report.
C family
* The pragma redefine_extname will now macro expand its tokens for
compatibility with SunPRO.
* In the next release of GCC, 4.3, -std=c99 or -std=gnu99 will direct
GCC to handle inline functions as specified in the C99 standard. In
preparation for this, GCC 4.2 will warn about any use of non-static
inline functions in gnu99 or c99 mode. This new warning may be
disabled with the new gnu_inline function attribute or the new
-fgnu89-inline command-line option. Also, GCC 4.2 and later will
define one of the preprocessor macros __GNUC_GNU_INLINE__ or
__GNUC_STDC_INLINE__ to indicate the semantics of inline functions
in the current compilation.
* A new command-line option -Waddress has been added to warn about
suspicious uses of memory addresses as, for example, using the
address of a function in a conditional expression, and comparisons
against the memory address of a string literal. This warning is
enabled by -Wall.
C++
* C++ visibility handling has been overhauled.
Restricted visiblity is propagated from classes to members, from
functions to local statics, and from templates and template
arguments to instantiations, unless the latter has explicitly
declared visibility.
The visibility attribute for a class must come between the
class-key and the name, not after the closing brace.
Attributes are now allowed for enums and elaborated-type-specifiers
that only declare a type.
Members of the anonymous namespace are now local to a particular
translation unit, along with any other declarations which use them,
though they are still treated as having external linkage for
language semantics.
* The (undocumented) extension which permitted templates with default
arguments to be bound to template template parameters with fewer
parameters has been removed. For example:
template <template <typename> class C>
void f(C<double>) {}
template <typename T, typename U = int>
struct S {};
template void f(S<double>);
is no longer accepted by G++. The reason this code is not accepted
is that S is a template with two parameters; therefore, it cannot
be bound to C which has only one parameter.
* The <?, >?, <?=, and >?= operators, deprecated in previous GCC
releases, have been removed.
* The command-line option -fconst-strings, deprecated in previous GCC
releases, has been removed.
* The configure variable enable-__cxa_atexit is now enabled by
default for more targets. Enabling this variable is necessary in
order for static destructors to be executed in the correct order,
but it depends upon the presence of a non-standard C library in the
target library in order to work. The variable is now enabled for
more targets which are known to have suitable C libraries.
* -Wextra will produce warnings for if statements with a semicolon as
the only body, to catch code like:
if (a);
return 1;
return 0;
To suppress the warning in valid cases, use { } instead.
* The C++ frontend now also produces strict aliasing warnings when
-fstrict-aliasing -Wstrict-aliasing is in effect.
Runtime Library (libstdc++)
* Added support for TR1 <random>, <complex>, and C compatibility
headers. In addition, a lock-free version of shared_ptr was
contributed as part of Phillip Jordan's Google Summer of Code
project on lock-free containers. ([3]Implementation status of TR1)
* In association with the Summer of Code work on lock-free
containers, the interface for atomic builtins was adjusted,
creating simpler alternatives for non-threaded code paths. Also,
usage was consolidated and all elements were moved from namespace
std to namespace__gnu_cxx. Affected interfaces are the functions
__exchange_and_add, __atomic_add, and the objects __mutex,
__recursive_mutex, and __scoped_lock.
* Support for versioning weak symbol names via namespace association
was added. However, as this changes the names of exported symbols,
this is turned off by default in the current ABI. Intrepid users
can enable this feature by using
--enable-symvers=gnu-versioned-namespace during configuration.
* Revised, simplified, and expanded policy-based associative
containers, including data types for tree and trie forms
(basic_tree, tree, trie), lists (list_update), and both
collision-chaining and probing hash-based containers
(basic_hash_table, cc_hash_table, gp_hash_table). More details per
the [4]documentation.
* The implementation of the debug mode was modified, whereby the
debug namespaces were nested inside of namespace std and namespace
__gnu_cxx in order to resolve some long standing corner cases
involving name lookup. Debug functionality from the policy-based
data structures was consolidated and enabled with the single macro,
_GLIBCXX_DEBUG. See PR 26142 for more information.
* Added extensions for type traits: __conditional_type,
__numeric_traits, __add_unsigned, __removed_unsigned, __enable_if.
* Added a typelist implementation for compile-time meta-programming.
Elements for typelist construction and operation can be found
within namespace __gnu_cxx::typelist.
* Added a new allocator, __gnu_cxx::throw_allocator, for testing
exception-safety.
* Enabled library-wide visibility control, allowing -fvisibility to
be used.
* Consolidated all nested namespaces and the conversion of
__gnu_internal implementation-private details to anonymous
namespaces whenever possible.
* Implemented LWG resolutions DR 431 and DR 538.
Fortran
* Support for allocatable components has been added (TR 15581 and
Fortran 2003).
* Support for the Fortran 2003 streaming IO extension has been added.
* The GNU Fortran compiler now uses 4-byte record markers by default
for unformatted files to be compatible with g77 and most other
compilers. The implementation allows for records greater than 2 GB
and is compatible with several other compilers. Older versions of
gfortran used 8-byte record markers by default (on most systems).
In order to change the length of the record markers, e.g. to read
unformatted files created by older gfortran versions, the
[5]-frecord-marker=8 option can be used.
Java (GCJ)
* A new command-line option -static-libgcj has been added for targets
that use a linker compatible with GNU Binutils. As its name
implies, this causes libgcj to be linked statically. In some cases
this causes the resulting executable to start faster and use less
memory than if the shared version of libgcj were used. However
caution should be used as it can also cause essential parts of the
library to be omitted. Some of these issues are discussed in:
[6]http://gcc.gnu.org/wiki/Statically_linking_libgcj
* fastjar is no longer bundled with GCC. To build libgcj, you will
need either InfoZIP (both zip and unzip) or an external jar
program. In the former case, the GCC build will install a jar shell
script that is based on InfoZIP and provides the same functionality
as fastjar.
New Targets and Target Specific Improvements
IA-32/x86-64
* -mtune=generic can now be used to generate code running well on
common x86 chips. This includes AMD Athlon, AMD Opteron, Intel
Pentium-M, Intel Pentium 4 and Intel Core 2.
* -mtune=native and -march=native will produce code optimized for the
host architecture as detected using the cpuid instruction.
* Added a new command-line option -fstackrealign and and
__attribute__ ((force_align_arg_pointer)) to realign the stack at
runtime. This allows functions compiled with a vector-aligned stack
to be invoked from legacy objects that keep only word-alignment.
SPARC
* The default CPU setting has been changed from V7 to V9 in 32-bit
mode on Solaris 7 and above. This is already the case in 64-bit
mode. It can be overridden by specifying --with-cpu at configure
time.
* Back-end support of built-in functions for atomic memory access has
been implemented.
* Support for the Sun UltraSPARC T1 (Niagara) processor has been
added.
M32C
* Various bug fixes have made some functions (notably, functions
returning structures) incompatible with previous releases.
Recompiling all libraries is recommended. Note that code quality
has considerably improved since 4.1, making a recompile even more
beneficial.
MIPS
* Added support for the Broadcom SB-1A core.
IA-64
* Added support for IA-64 data and control speculation. By default
speculation is enabled only during second scheduler pass. A number
of machine flags was introduced to control the usage of speculation
for both scheduler passes.
HPPA
* Added Java language support (libffi and libjava) for 32-bit HP-UX
11 target.
Obsolete Systems
Documentation improvements
PDF Documentation
* A make pdf target has been added to the top-level makefile,
enabling automated production of PDF documentation files.
(Front-ends external to GCC should modify their Make-lang.in file
to add a lang.pdf: target.)
Other significant improvements
Build system improvements
* All the components of the compiler are now bootstrapped by default.
This improves the resilience to bugs in the system compiler or
binary compatibility problems, as well as providing better testing
of GCC 4.2 itself. In addition, if you build the compiler from a
combined tree, the assembler, linker, etc. will also be
bootstrapped (i.e. built with themselves).
You can disable this behavior, and go back to the pre-GCC 4.2 set
up, by configuring GCC with --disable-bootstrap.
* The rules that configure follows to find target tools resemble more
closely the locations that the built compiler will search. In
addition, you can use the new configure option --with-target-tools
to specify where to find the target tools used during the build,
without affecting what the built compiler will use.
This can be especially useful when building packages of GCC. For
example, you may want to build GCC with GNU as or ld, even if the
resulting compiler to work with the native assembler and linker. To
do so, you can use --with-target-tools to point to the native
tools.
Incompatible changes to the build system
* Front-ends external to GCC should modify their Make-lang.in file to
replace double-colon rules (e.g. dvi::) with normal rules (like
lang.dvi:). Front-end makefile hooks do not use double-colon rules
anymore.
* Up to GCC 4.1, a popular way to specify the target tools used
during the build was to create directories named gas, binutils,
etc. in the build tree, and create links to the tools from there.
This does not work any more when the compiler is bootstrapped. The
new configure option --with-target-tools provides a better way to
achieve the same effect, and works for all native and cross
settings.
Please send FSF & GNU inquiries & questions to [7]gnu@gnu.org. There
are also [8]other ways to contact the FSF.
These pages are maintained by [9]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [10]GCC manuals. If that fails, the
[11]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [12]gcc@gnu.org or [13]gcc@gcc.gnu.org.
All of our lists have [14]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2009-11-08 [15]Valid XHTML 1.0
References
1. http://gcc.gnu.org/projects/gomp/
2. http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
3. http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt01ch01.html#manual.intro.status.standard.tr1
4. http://gcc.gnu.org/onlinedocs/libstdc++/ext/pb_ds/index.html
5. http://gcc.gnu.org/onlinedocs/gfortran/Runtime-Options.html
6. http://gcc.gnu.org/wiki/Statically_linking_libgcj
7. mailto:gnu@gnu.org
8. http://www.gnu.org/home.html#ContactInfo
9. http://gcc.gnu.org/about.html
10. http://gcc.gnu.org/onlinedocs/
11. mailto:gcc-help@gcc.gnu.org
12. mailto:gcc@gnu.org
13. mailto:gcc@gcc.gnu.org
14. http://gcc.gnu.org/lists.html
15. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.1/index.html
GCC 4.1 Release Series
February 13, 2007
The [1]GNU project and the GCC developers are pleased to announce the
release of GCC 4.1.2.
This release is a bug-fix release, containing fixes for regressions in
GCC 4.1.1 relative to previous releases of GCC.
Release History
GCC 4.1.2
February 13, 2007 ([2]changes)
GCC 4.1.1
May 24, 2006 ([3]changes)
GCC 4.1.0
February 28, 2006 ([4]changes)
References and Acknowledgements
GCC used to stand for the GNU C Compiler, but since the compiler
supports several other languages aside from C, it now stands for the
GNU Compiler Collection.
A list of [5]successful builds is updated as new information becomes
available.
The GCC developers would like to thank the numerous people that have
contributed new features, improvements, bug fixes, and other changes as
well as test results to GCC. This [6]amazing group of volunteers is
what makes GCC successful.
For additional information about GCC please refer to the [7]GCC project
web site or contact the [8]GCC development mailing list.
To obtain GCC please use [9]our mirror sites or [10]our SVN server.
Please send FSF & GNU inquiries & questions to [11]gnu@gnu.org. There
are also [12]other ways to contact the FSF.
These pages are maintained by [13]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [14]GCC manuals. If that fails, the
[15]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [16]gcc@gnu.org or [17]gcc@gcc.gnu.org.
All of our lists have [18]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2008-10-04 [19]Valid XHTML 1.0
References
1. http://www.gnu.org/
2. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2
3. http://gcc.gnu.org/gcc-4.1/changes.html
4. http://gcc.gnu.org/gcc-4.1/changes.html
5. http://gcc.gnu.org/gcc-4.1/buildstat.html
6. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
7. http://gcc.gnu.org/index.html
8. mailto:gcc@gcc.gnu.org
9. http://gcc.gnu.org/mirrors.html
10. http://gcc.gnu.org/svn.html
11. mailto:gnu@gnu.org
12. http://www.gnu.org/home.html#ContactInfo
13. http://gcc.gnu.org/about.html
14. http://gcc.gnu.org/onlinedocs/
15. mailto:gcc-help@gcc.gnu.org
16. mailto:gcc@gnu.org
17. mailto:gcc@gcc.gnu.org
18. http://gcc.gnu.org/lists.html
19. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.1/changes.html
GCC 4.1 Release Series
Changes, New Features, and Fixes
The latest release in the 4.1 release series is [1]GCC 4.1.2.
Caveats
General Optimizer Improvements
* GCC now has infrastructure for inter-procedural optimizations and
the following inter-procedural optimizations are implemented:
+ Profile guided inlining. When doing profile feedback guided
optimization, GCC can now use the profile to make better
informed decisions on whether inlining of a function is
profitable or not. This means that GCC will no longer inline
functions at call sites that are not executed very often, and
that functions at hot call sites are more likely to be
inlined.
A new parameter min-inline-recursive-probability is also now
available to throttle recursive inlining of functions with
small average recursive depths.
+ Discovery of pure and const functions, a form of side-effects
analysis. While older GCC releases could also discover such
special functions, the new IPA-based pass runs earlier so that
the results are available to more optimizers. The pass is also
simply more powerful than the old one.
+ Analysis of references to static variables and type escape
analysis, also forms of side-effects analysis. The results of
these passes allow the compiler to be less conservative about
call-clobbered variables and references. This results in more
redundant loads being eliminated and in making static
variables candidates for register promotion.
+ Improvement of RTL-based alias analysis. The results of type
escape analysis are fed to the RTL type-based alias analyzer,
allowing it to disambiguate more memory references.
+ Interprocedural constant propagation and function versioning.
This pass looks for functions that are always called with the
same constant value for one or more of the function arguments,
and propagates those constants into those functions.
+ GCC will now eliminate static variables whose usage was
optimized out.
+ -fwhole-program --combine can now be used to make all
functions in program static allowing whole program
optimization. As an exception, the main function and all
functions marked with the new externally_visible attribute are
kept global so that programs can link with runtime libraries.
* GCC can now do a form of partial dead code elimination (PDCE) that
allows code motion of expressions to the paths where the result of
the expression is actually needed. This is not always a win, so the
pass has been limited to only consider profitable cases. Here is an
example:
int foo (int *, int *);
int
bar (int d)
{
int a, b, c;
b = d + 1;
c = d + 2;
a = b + c;
if (d)
{
foo (&b, &c);
a = b + c;
}
printf ("%d\n", a);
}
The a = b + c can be sunk to right before the printf. Normal code
sinking will not do this, it will sink the first one above into the
else-branch of the conditional jump, which still gives you two
copies of the code.
* GCC now has a value range propagation pass. This allows the
compiler to eliminate bounds checks and branches. The results of
the pass can also be used to accurately compute branch
probabilities.
* The pass to convert PHI nodes to straight-line code (a form of
if-conversion for GIMPLE) has been improved significantly. The two
most significant improvements are an improved algorithm to
determine the order in which the PHI nodes are considered, and an
improvement that allow the pass to consider if-conversions of basic
blocks with more than two predecessors.
* Alias analysis improvements. GCC can now differentiate between
different fields of structures in Tree-SSA's virtual operands form.
This lets stores/loads from non-overlapping structure fields not
conflict. A new algorithm to compute points-to sets was contributed
that can allows GCC to see now that p->a and p->b, where p is a
pointer to a structure, can never point to the same field.
* Various enhancements to auto-vectorization:
+ Incrementally preserve SSA form when vectorizing.
+ Incrementally preserve loop-closed form when vectorizing.
+ Improvements to peeling for alignment: generate better code
when the misalignment of an access is known at compile time,
or when different accesses are known to have the same
misalignment, even if the misalignment amount itself is
unknown.
+ Consider dependence distance in the vectorizer.
+ Externalize generic parts of data reference analysis to make
this analysis available to other passes.
+ Vectorization of conditional code.
+ Reduction support.
* GCC can now partition functions in sections of hot and cold code.
This can significantly improve performance due to better
instruction cache locality. This feature works best together with
profile feedback driven optimization.
* A new pass to avoid saving of unneeded arguments to the stack in
vararg functions if the compiler can prove that they will not be
needed.
* Transition of basic block profiling to tree level implementation
has been completed. The new implementation should be considerably
more reliable (hopefully avoiding profile mismatch errors when
using -fprofile-use or -fbranch-probabilities) and can be used to
drive higher level optimizations, such as inlining.
The -ftree-based-profiling command-line option was removed and
-fprofile-use now implies disabling old RTL level loop optimizer
(-fno-loop-optimize). Speculative prefetching optimization
(originally enabled by -fspeculative-prefetching) was removed.
New Languages and Language specific improvements
C and Objective-C
* The old Bison-based C and Objective-C parser has been replaced by a
new, faster hand-written recursive-descent parser.
Ada
* The build infrastructure for the Ada runtime library and tools has
been changed to be better integrated with the rest of the build
infrastructure of GCC. This should make doing cross builds of Ada a
bit easier.
C++
* ARM-style name-injection of friend declarations is no longer the
default. For example:
struct S {
friend void f();
};
void g() { f(); }
will not be accepted; instead a declaration of f will need to be
present outside of the scope of S. The new -ffriend-injection
option will enable the old behavior.
* The (undocumented) extension which permitted templates with default
arguments to be bound to template template parameters with fewer
parameters has been deprecated, and will be removed in the next
major release of G++. For example:
template <template <typename> class C>
void f(C<double>) {}
template <typename T, typename U = int>
struct S {};
template void f(S<double>);
makes use of the deprecated extension. The reason this code is not
valid ISO C++ is that S is a template with two parameters;
therefore, it cannot be bound to C which has only one parameter.
Runtime Library (libstdc++)
* Optimization work:
+ A new implementation of std::search_n is provided, better
performing in case of random access iterators.
+ Added further efficient specializations of istream functions,
i.e., character array and string extractors.
+ Other smaller improvements throughout.
* Policy-based associative containers, designed for high-performance,
flexibility and semantic safety are delivered in ext/pb_assoc.
* A versatile string class, __gnu_cxx::__versa_string, providing
facilities conforming to the standard requirements for
basic_string, is delivered in <ext/vstring.h>. In particular:
+ Two base classes are provided: the default one avoids
reference counting and is optimized for short strings; the
alternate one, still uses it while improving in a few low
level areas (e.g., alignment). See vstring_fwd.h for some
useful typedefs.
+ Various algorithms have been rewritten (e.g., replace), the
code streamlined and simple optimizations added.
+ Option 3 of DR 431 is implemented for both available bases,
thus improving the support for stateful allocators.
* As usual, many bugs have been fixed (e.g., libstdc++/13583,
libstdc++/23953) and LWG resolutions put into effect for the first
time (e.g., DR 280, DR 464, N1780 recommendations for DR 233, TR1
Issue 6.19). The implementation status of TR1 is now tracked in the
docs in tr1.html.
Objective-C++
* A new language front end for Objective-C++ has been added. This
language allows users to mix the object oriented features of
Objective-C with those of C++.
Java (GCJ)
* Core library (libgcj) updates based on GNU Classpath 0.15 - 0.19
features (plus some 0.20 bug-fixes)
+ Networking
o The java.net.HttpURLConnection implementation no longer
buffers the entire response body in memory. This means
that response bodies larger than available memory can now
be handled.
+ (N)IO
o NIO FileChannel.map implementation, fast bulk put
implementation for DirectByteBuffer (speeds up this
method 10x).
o FileChannel.lock() and FileChannel.force() implemented.
+ XML
o gnu.xml fix for nodes created outside a namespace
context.
o Add support for output indenting and
cdata-section-elements output instruction in
xml.transform.
o xml.xpath corrections for cases where elements/attributes
might have been created in non-namespace-aware mode.
Corrections to handling of XSL variables and minor
conformance updates.
+ AWT
o GNU JAWT implementation, the AWT Native Interface, which
allows direct access to native screen resources from
within a Canvas's paint method. GNU Classpath Examples
comes with a Demo, see libjava/classpath/examples/README.
o awt.datatransfer updated to 1.5 with support for
FlavorEvents. The gtk+ awt peers now allow copy/paste of
text, images, URIs/files and serialized objects with
other applications and tracking clipboard change events
with gtk+ 2.6 (for gtk+ 2.4 only text and serialized
objects are supported). A GNU Classpath Examples
datatransfer Demo was added to show the new
functionality.
o Split gtk+ awt peers event handling in two threads and
improve gdk lock handling (solves several awt lock ups).
o Speed up awt Image loading.
o Better gtk+ scrollbar peer implementation when using gtk+
>= 2.6.
o Handle image loading errors correctly for gdkpixbuf and
MediaTracker.
o Better handle GDK lock. Properly prefix gtkpeer native
functions (cp_gtk).
o GdkGraphics2D has been updated to use Cairo 0.5.x or
higher.
o BufferedImage and GtkImage rewrites. All image drawing
operations should now work correctly (flipping requires
gtk+ >= 2.6)
o Future Graphics2D, image and text work is documented at:
[2]http://developer.classpath.org/mediation/ClasspathGrap
hicsImagesText
o When gtk+ 2.6 or higher is installed the default log
handler will produce stack traces whenever a WARNING,
CRITICAL or ERROR message is produced.
+ Free Swing
o The RepaintManager has been reworked for more efficient
painting, especially for large GUIs.
o The layout manager OverlayLayout has been implemented,
the BoxLayout has been rewritten to make use of the
SizeRequirements utility class and caching for more
efficient layout.
o Improved accessibility support.
o Significant progress has been made in the implementation
of the javax.swing.plaf.metal package, with most UI
delegates in a working state now. Please test this with
your own applications and provide feedback that will help
us to improve this package.
o The GUI demo (gnu.classpath.examples.swing.Demo) has been
extended to highlight various features in our Free Swing
implementation. And it includes a look and feel switcher
for Metal (default), Ocean and GNU themes.
o The javax.swing.plaf.multi package is now implemented.
o Editing and several key actions for JTree and JTable were
implemented.
o Lots of icons and look and feel improvements for Free
Swing basic and metal themes were added. Try running the
GNU Classpath Swing Demo in examples
(gnu.classpath.examples.swing.Demo) with:
-Dswing.defaultlaf=javax.swing.plaf.basic.BasicLookAndFee
l or
-Dswing.defaultlaf=javax.swing.plaf.metal.MetalLookAndFee
l
o Start of styled text capabilites for java.swing.text.
o DefaultMutableTreeNode pre-order, post-order, depth-first
and breadth-first traversal enumerations implemented.
o JInternalFrame colors and titlebar draw properly.
o JTree is working up to par (icons, selection and keyboard
traversal).
o JMenus were made more compatible in visual and
programmatic behavior.
o JTable changeSelection and multiple selections
implemented.
o JButton and JToggleButton change states work properly
now.
o JFileChooser fixes.
o revalidate() and repaint() fixes which make Free Swing
much more responsive.
o MetalIconFactory implemented.
o Free Swing Top-Level Compatibility. JFrame, JDialog,
JApplet, JInternalFrame, and JWindow are now 1.5
compatible in the sense that you can call add() and
setLayout() directly on them, which will have the same
effect as calling getContentPane().add() and
getContentPane().setLayout().
o The JTree interface has been completed. JTrees now
recognizes mouse clicks and selections work.
o BoxLayout works properly now.
o Fixed GrayFilter to actually work.
o Metal SplitPane implemented.
o Lots of Free Swing text and editor stuff work now.
+ Free RMI and Corba
o Andrew Watson, Vice President and Technical Director of
the Object Management Group, has officially assigned us
20 bit Vendor Minor Code Id: 0x47430 ("GC") that will
mark remote classpath-specific system exceptions.
Obtaining the VMCID means that GNU Classpath now is a
recogniseable type of node in a highly interoperable
CORBA world.
o GNU Classpath now includes the first working draft to
support the RMI over IIOP protocol. The current
implementation is capable of remote invocations,
transferring various Serializables and Externalizables
via RMI-IIOP protocol. It can flatten graphs and, at
least for the simple cases, is interoperable with 1.5
JDKs.
o org.omg.PortableInterceptor and related functionality in
other packages is now implemented:
# The sever and client interceptors work as required
since 1.4.
# The IOR interceptor works as needed for 1.5.
o The org.omg.DynamicAny package is completed and passes
the prepared tests.
o The Portable Object Adapter should now support the output
of the recent IDL to java compilers. These compilers now
generate servants and not CORBA objects as before, making
the output depend on the existing POA implementation.
Completing POA means that such code can already be tried
to run on Classpath. Our POA is tested for the following
usager scenarios:
# POA converts servant to the CORBA object.
# Servant provides to the CORBA object.
# POA activates new CORBA object with the given Object
Id (byte array) that is later accessible for the
servant.
# During the first call, the ServantActivator provides
servant for this and all subsequent calls on the
current object.
# During each call, the ServantLocator provides
servant for this call only.
# ServantLocator or ServantActivator forwards call to
another server.
# POA has a single servant, responsible for all
objects.
# POA has a default servant, but some objects are
explicitly connected to they specific servants.
The POA is verified using tests from the former
cost.omg.org.
o The CORBA implementation is now a working prototype that
should support features up to 1.3 inclusive. We invite
groups writing CORBA dependent applications to try
Classpath implementation, reporting any possible bugs.
The CORBA prototype is interoperable with Sun's
implementation v 1.4, transferring object references,
primitive types, narrow and wide strings, arrays,
structures, trees, abstract interfaces and value types
(feature of CORBA 2.3) between these two platforms.
Remote exceptions are transferred and handled correctly.
The stringified object references (IORs) from various
sources are parsed as required. The transient (for
current session) and permanent (till jre restart)
redirections work. Both Little and Big Endian encoded
messages are accepted. The implementation is verified
using tests from the former cost.omg.org. The current
release includes working examples (see the examples
directory), demonstrating the client-server
communication, using either CORBA Request or IDL-based
stub (usually generated by a IDL to java compiler). These
examples also show how to use the Classpath CORBA naming
service. The IDL to java compiler is not yet written, but
as our library must be compatible, it naturally accepts
the output of other idlj implementations.
+ Misc
o Updated TimeZone data against Olson tzdata2005l.
o Make zip and jar packages UTF-8 clean.
o "native" code builds and compiles (warning free) on
Darwin and Solaris.
o java.util.logging.FileHandler now rotates files.
o Start of a generic JDWP framework in gnu/classpath/jdwp.
This is unfinished, but feedback (at classpath@gnu.org)
from runtime hackers is greatly appreciated. Although
most of the work is currently being done around gcj/gij
we want this framework to be as VM neutral as possible.
Early design is described in:
[3]http://gcc.gnu.org/ml/java/2005-05/msg00260.html
o QT4 AWT peers, enable by giving configure
--enable-qt-peer. Included, but not ready for production
yet. They are explicitly disabled and not supported. But
if you want to help with the development of these new
features we are interested in feedback. You will have to
explicitly enable them to try them out (and they will
most likely contain bugs).
o Documentation fixes all over the place. See
[4]http://developer.classpath.org/doc/
New Targets and Target Specific Improvements
IA-32/x86-64
* The x86-64 medium model (that allows building applications whose
data segment exceeds 4GB) was redesigned to match latest ABI draft.
New implementation split large datastructures into separate segment
improving performance of accesses to small datastructures and also
allows linking of small model libraries into medium model programs
as long as the libraries are not accessing the large datastructures
directly. Medium model is also supported in position independent
code now.
The ABI change results in partial incompatibility among medium
model objects. Linking medium model libraries (or objects) compiled
with new compiler into medium model program compiled with older
will likely result in exceeding ranges of relocations.
Binutils 2.16.91 or newer are required for compiling medium model
now.
RS6000 (POWER/PowerPC)
* The AltiVec vector primitives in <altivec.h> are now implemented in
a way that puts a smaller burden on the preprocessor, instead
processing the "overloading" in the front ends. This should benefit
compilation speed on AltiVec vector code.
* AltiVec initializers now are generated more efficiently.
* The popcountb instruction available on POWER5 now is generated.
* The floating point round to integer instructions available on
POWER5+ now is generated.
* Floating point divides can be synthesized using the floating point
reciprocal estimate instructions.
* Double precision floating point constants are initialized as single
precision values if they can be represented exactly.
S/390, zSeries and System z9
* Support for the IBM System z9 109 processor has been added. When
using the -march=z9-109 option, the compiler will generate code
making use of instructions provided by the extended immediate
facility.
* Support for 128-bit IEEE floating point has been added. When using
the -mlong-double-128 option, the compiler will map the long double
data type to 128-bit IEEE floating point. Using this option
constitutes an ABI change, and requires glibc support.
* Various changes to improve performance of generated code have been
implemented, including:
+ In functions that do not require a literal pool, register %r13
(which is traditionally reserved as literal pool pointer), can
now be freely used for other purposes by the compiler.
+ More precise tracking of register use allows the compiler to
generate more efficient function prolog and epilog code in
certain cases.
+ The SEARCH STRING, COMPARE LOGICAL STRING, and MOVE STRING
instructions are now used to implement C string functions.
+ The MOVE CHARACTER instruction with single byte overlap is now
used to implement the memset function with non-zero fill byte.
+ The LOAD ZERO instructions are now used where appropriate.
+ The INSERT CHARACTERS UNDER MASK, STORE CHARACTERS UNDER MASK,
and INSERT IMMEDIATE instructions are now used more frequently
to optimize bitfield operations.
+ The BRANCH ON COUNT instruction is now used more frequently.
In particular, the fact that a loop contains a subroutine call
no longer prevents the compiler from using this instruction.
+ The compiler is now aware that all shift and rotate
instructions implicitly truncate the shift count to six bits.
* Back-end support for the following generic features has been
implemented:
+ The full set of [5]built-in functions for atomic memory
access.
+ The -fstack-protector feature.
+ The optimization pass avoiding unnecessary stores of incoming
argument registers in functions with variable argument list.
SPARC
* The default code model in 64-bit mode has been changed from
Medium/Anywhere to Medium/Middle on Solaris.
* TLS support is disabled by default on Solaris prior to release 10.
It can be enabled on TLS-capable Solaris 9 versions (4/04 release
and later) by specifying --enable-tls at configure time.
MorphoSys
* Support has been added for this new architecture.
Obsolete Systems
Documentation improvements
Other significant improvements
* GCC can now emit code for protecting applications from
stack-smashing attacks. The protection is realized by buffer
overflow detection and reordering of stack variables to avoid
pointer corruption.
* Some built-in functions have been fortified to protect them against
various buffer overflow (and format string) vulnerabilities.
Compared to the mudflap bounds checking feature, the safe builtins
have far smaller overhead. This means that programs built using
safe builtins should not experience any measurable slowdown.
GCC 4.1.2
This is the [6]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.1.2 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
When generating code for a shared library, GCC now recognizes that
global functions may be replaced when the program runs. Therefore, it
is now more conservative in deducing information from the bodies of
functions. For example, in this example:
void f() {}
void g() {
try { f(); }
catch (...) {
cout << "Exception";
}
}
G++ would previously have optimized away the catch clause, since it
would have concluded that f cannot throw exceptions. Because users may
replace f with another function in the main body of the program, this
optimization is unsafe, and is no longer performed. If you wish G++ to
continue to optimize as before, you must add a throw() clause to the
declaration of f to make clear that it does not throw exceptions.
Please send FSF & GNU inquiries & questions to [7]gnu@gnu.org. There
are also [8]other ways to contact the FSF.
These pages are maintained by [9]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [10]GCC manuals. If that fails, the
[11]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [12]gcc@gnu.org or [13]gcc@gcc.gnu.org.
All of our lists have [14]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2009-01-25 [15]Valid XHTML 1.0
References
1. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2
2. http://developer.classpath.org/mediation/ClasspathGraphicsImagesText
3. http://gcc.gnu.org/ml/java/2005-05/msg00260.html
4. http://developer.classpath.org/doc/
5. http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
6. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.1.2
7. mailto:gnu@gnu.org
8. http://www.gnu.org/home.html#ContactInfo
9. http://gcc.gnu.org/about.html
10. http://gcc.gnu.org/onlinedocs/
11. mailto:gcc-help@gcc.gnu.org
12. mailto:gcc@gnu.org
13. mailto:gcc@gcc.gnu.org
14. http://gcc.gnu.org/lists.html
15. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.0/index.html
GCC 4.0 Release Series
January 31, 2007
The [1]GNU project and the GCC developers are pleased to announce the
release of GCC 4.0.4.
This release is a bug-fix release, containing fixes for regressions in
GCC 4.0.3 relative to previous releases of GCC.
Release History
GCC 4.0.4
January 31, 2007 ([2]changes)
GCC 4.0.3
March 10, 2006 ([3]changes)
GCC 4.0.2
September 28, 2005 ([4]changes)
GCC 4.0.1
July 7, 2005 ([5]changes)
GCC 4.0.0
April 20, 2005 ([6]changes)
References and Acknowledgements
GCC used to stand for the GNU C Compiler, but since the compiler
supports several other languages aside from C, it now stands for the
GNU Compiler Collection.
A list of [7]successful builds is updated as new information becomes
available.
The GCC developers would like to thank the numerous people that have
contributed new features, improvements, bug fixes, and other changes as
well as test results to GCC. This [8]amazing group of volunteers is
what makes GCC successful.
For additional information about GCC please refer to the [9]GCC project
web site or contact the [10]GCC development mailing list.
To obtain GCC please use [11]our mirror sites, or [12]our SVN server.
Please send FSF & GNU inquiries & questions to [13]gnu@gnu.org. There
are also [14]other ways to contact the FSF.
These pages are maintained by [15]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [16]GCC manuals. If that fails, the
[17]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [18]gcc@gnu.org or [19]gcc@gcc.gnu.org.
All of our lists have [20]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2008-07-26 [21]Valid XHTML 1.0
References
1. http://www.gnu.org/
2. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4
3. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.3
4. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.2
5. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.1
6. http://gcc.gnu.org/gcc-4.0/changes.html
7. http://gcc.gnu.org/gcc-4.0/buildstat.html
8. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
9. http://gcc.gnu.org/index.html
10. mailto:gcc@gcc.gnu.org
11. http://gcc.gnu.org/mirrors.html
12. http://gcc.gnu.org/svn.html
13. mailto:gnu@gnu.org
14. http://www.gnu.org/home.html#ContactInfo
15. http://gcc.gnu.org/about.html
16. http://gcc.gnu.org/onlinedocs/
17. mailto:gcc-help@gcc.gnu.org
18. mailto:gcc@gnu.org
19. mailto:gcc@gcc.gnu.org
20. http://gcc.gnu.org/lists.html
21. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.0/changes.html
GCC 4.0 Release Series
Changes, New Features, and Fixes
The latest release in the 4.0 release series is [1]GCC 4.0.4.
Caveats
* GCC now generates location lists by default when compiling with
debug info and optimization.
+ GDB 6.0 and older crashes when it sees location lists. GDB 6.1
or later is needed to debug binaries containing location
lists.
+ When you are trying to view a value of a variable in a part of
a function where it has no location (for example when the
variable is no longer used and thus its location was used for
something else) GDB will say that it is not available.
You can disable generating location lists by -fno-var-tracking.
* GCC no longer accepts the -fwritable-strings option. Use named
character arrays when you need a writable string.
* The options -freduce-all-givs and -fmove-all-movables have been
discontinued. They were used to circumvent a shortcoming in the
heuristics of the old loop optimization code with respect to common
Fortran constructs. The new (tree) loop optimizer works differently
and doesn't need those work-arounds.
* The graph-coloring register allocator, formerly enabled by the
option -fnew-ra, has been discontinued.
* -I- has been deprecated. -iquote is meant to replace the need for
this option.
* The MIPS -membedded-pic and -mrnames options have been removed.
* All MIPS targets now require the GNU assembler. In particular, IRIX
configurations can no longer use the MIPSpro assemblers, although
they do still support the MIPSpro linkers.
* The SPARC option -mflat has been removed.
* English-language diagnostic messages will now use Unicode quotation
marks in UTF-8 locales. (Non-English messages already used the
quotes appropriate for the language in previous releases.) If your
terminal does not support UTF-8 but you are using a UTF-8 locale
(such locales are the default on many GNU/Linux systems) then you
should set LC_CTYPE=C in the environment to disable that locale.
Programs that parse diagnostics and expect plain ASCII
English-language messages should set LC_ALL=C. See [2]Markus Kuhn's
explanation of Unicode quotation marks for more information.
* The specs file is no longer installed on most platforms. Most users
will be totally unaffected. However, if you are accustomed to
editing the specs file yourself, you will now have to use the
-dumpspecs option to generate the specs file, and then edit the
resulting file.
General Optimizer Improvements
* The [3]tree ssa branch has been merged. This merge has brought in a
completely new optimization framework based on a higher level
intermediate representation than the existing RTL representation.
Numerous new code transformations based on the new framework are
available in GCC 4.0, including:
+ Scalar replacement of aggregates
+ Constant propagation
+ Value range propagation
+ Partial redundancy elimination
+ Load and store motion
+ Strength reduction
+ Dead store elimination
+ Dead and unreachable code elimination
+ [4]Autovectorization
+ Loop interchange
+ Tail recursion by accumulation
Many of these passes outperform their counterparts from previous
GCC releases.
* [5]Swing Modulo Scheduling (SMS). An RTL level instruction
scheduling optimization intended for loops that perform heavy
computations.
New Languages and Language specific improvements
C family
* The sentinel attribute has been added to GCC. This function
attribute allows GCC to warn when variadic functions such as execl
are not NULL terminated. See the GCC manual for a complete
description of its behavior.
* Given __attribute__((alias("target"))) it is now an error if target
is not a symbol, defined in the same translation unit. This also
applies to aliases created by #pragma weak alias=target. This is
because it's meaningless to define an alias to an undefined symbol.
On Solaris, the native assembler would have caught this error, but
GNU as does not.
C and Objective-C
* The -Wstrict-aliasing=2 option has been added. This warning catches
all unsafe cases, but it may also give a warning for some cases
that are safe.
* The cast-as-lvalue, conditional-expression-as-lvalue and
compound-expression-as-lvalue extensions, which were deprecated in
3.3.4 and 3.4, have been removed.
* The -fwritable-strings option, which was deprecated in 3.4, has
been removed.
* #pragma pack() semantics have been brought closer to those used by
other compilers. This also applies to C++.
* Taking the address of a variable with register storage is invalid
in C. GCC now issues an error instead of a warning.
* Arrays of incomplete element type are invalid in C. GCC now issues
an error for such arrays. Declarations such as extern struct s x[];
(where struct s has not been defined) can be moved after the
definition of struct s. Function parameters declared as arrays of
incomplete type can instead be declared as pointers.
C++
* When compiling without optimizations (-O0), the C++ frontend is
much faster than in any previous versions of GCC. Independent
testers have measured speed-ups up to 25% in real-world production
code, compared to the 3.4 family (which was already the fastest
version to date). Upgrading from older versions might show even
bigger improvements.
* ELF visibility attributes can now be applied to a class type, so
that it affects every member function of a class at once, without
having to specify each individually:
class __attribute__ ((visibility("hidden"))) Foo
{
int foo1();
void foo2();
};
The syntax is deliberately similar to the __declspec() system used
by Microsoft Windows based compilers, allowing cross-platform
projects to easily reuse their existing macro system for denoting
exports and imports. By explicitly marking internal classes never
used outside a binary as hidden, one can completely avoid PLT
indirection overheads during their usage by the compiler. You can
find out more about the advantages of this at
[6]http://people.redhat.com/drepper/dsohowto.pdf
* The -fvisibility-inlines-hidden option has been added which marks
all inlineable functions as having hidden ELF visibility, thus
removing their symbol and typeinfo from the exported symbol table
of the output ELF binary. Using this option can reduce the exported
symbol count of template-heavy code by up to 40% with no code
change at all, thus notably improving link and load times for the
binary as well as a reduction in size of up to 10%. Also, check the
new [7]-fvisibility option.
* The compiler now uses the library interface specified by the [8]C++
ABI for thread-safe initialization of function-scope static
variables. Most users should leave this alone, but embedded
programmers may want to disable this by specifying
-fno-threadsafe-statics for a small savings in code size.
* Taking the address of an explicit register variable is no longer
supported. Note that C++ allows taking the address of variables
with register storage so this will continue to compile with a
warning. For example, assuming that r0 is a machine register:
register int foo asm ("r0");
register int bar;
&foo; // error, no longer accepted
&bar; // OK, with a warning
* G++ has an undocumented extension to virtual function covariancy
rules that allowed the overrider to return a type that was
implicitly convertable to the overridden function's return type.
For instance a function returning void * could be overridden by a
function returning T *. This is now deprecated and will be removed
in a future release.
* The G++ minimum and maximum operators (<? and >?) and their
compound forms (<?=) and >?=) have been deprecated and will be
removed in a future version. Code using these operators should be
modified to use std::min and std::max instead.
* Declaration of nested classes of class templates as friends are
supported:
template <typename T> struct A {
class B {};
};
class C {
template <typename T> friend class A<T>::B;
};
This complements the feature member functions of class templates as
friends introduced in GCC 3.4.0.
* When declaring a friend class using an unqualified name, classes
outside the innermost non-class scope are not searched:
class A;
namespace N {
class B {
friend class A; // Refer to N::A which has not been declared yet
// because name outside namespace N are not searched
friend class ::A; // Refer to ::A
};
}
Hiding the friend name until declaration is still not implemented.
* Friends of classes defined outside their namespace are correctly
handled:
namespace N {
class A;
}
class N::A {
friend class B; // Refer to N::B in GCC 4.0.0
// but ::B in earlier versions of GCC
};
Runtime Library (libstdc++)
* Optimization work:
+ Added efficient specializations of istream functions for char
and wchar_t.
+ Further performance tuning of strings, in particular wrt
single-char append and getline.
+ iter_swap - and therefore most of the mutating algorithms -
now makes an unqualified call to swap when the value_type of
the two iterators is the same.
* A large subset of the features in Technical Report 1 (TR1 for
short) is experimentally delivered (i.e., no guarantees about the
implementation are provided. In particular it is not promised that
the library will remain link-compatible when code using TR1 is
used):
+ General utilities such as reference_wrapper and shared_ptr.
+ Function objects, i.e., result_of, mem_fn, bind, function.
+ Support for metaprogramming.
+ New containers such as tuple, array, unordered_set,
unordered_map, unordered_multiset, unordered_multimap.
* As usual, many bugs have been fixed and LWG resolutions implemented
for the first time (e.g., DR 409).
Java
* In order to prevent naming conflicts with other implementations of
these tools, some GCJ binaries have been renamed:
+ rmic is now grmic,
+ rmiregistry is now grmiregistry, and
+ jar is now fastjar.
In particular, these names were problematic for the jpackage.org
packaging conventions which install symlinks in /usr/bin that point
to the preferred versions of these tools.
* The -findirect-dispatch argument to the compiler now works and
generates code following a new "binary compatibility" ABI. Code
compiled this way follows the binary compatibility rules of the
Java Language Specification.
* libgcj now has support for using GCJ as a JIT, using the
gnu.gcj.jit family of system properties.
* libgcj can now find a shared library corresponding to the bytecode
representation of a class. See the documentation for the new
gcj-dbtool program, and the new gnu.gcj.precompiled.db.path system
property.
* There have been many improvements to the class library. Here are
some highlights:
+ Much more of AWT and Swing exist.
+ Many new packages and classes were added, including
java.util.regex, java.net.URI, javax.crypto,
javax.crypto.interfaces, javax.crypto.spec, javax.net,
javax.net.ssl, javax.security.auth,
javax.security.auth.callback, javax.security.auth.login,
javax.security.auth.x500, javax.security.sasl, org.ietf.jgss,
javax.imageio, javax.imageio.event, javax.imageio.spi,
javax.print, javax.print.attribute,
javax.print.attribute.standard, javax.print.event, and
javax.xml
+ Updated SAX and DOM, and imported GNU JAXP
Fortran
* A new [9]Fortran front end has replaced the aging GNU Fortran 77
front end. The new front end supports Fortran 90 and Fortran 95. It
may not yet be as stable as the old Fortran front end.
Ada
* Ada (with tasking and Zero Cost Exceptions) is now available on
many more targets, including but not limited to: alpha-linux,
hppa-hpux, hppa-linux, powerpc-darwin, powerpc-linux, s390-linux,
s390x-linux, sparc-linux.
* Some of the new Ada 2005 features are now implemented like
Wide_Wide_Character and Ada.Containers.
* Many bugs have been fixed, tools and documentation improved.
* To compile Ada from the sources, install an older working Ada
compiler and then use --enable-languages=ada at configuration time,
since the Ada frontend is not currently activated by default. See
the [10]Installing GCC for details.
New Targets and Target Specific Improvements
H8/300
* The frame layout has changed. In the new layout, the prologue of a
function first saves registers and then allocate space for locals,
resulting in an 1% improvement on code size.
IA-32/x86-64 (AMD64)
* The acos, asin, drem, exp10, exp2, expm1, fmod, ilogb, log10,
log1p, log2, logb and tan mathematical builtins (and their float
and long double variants) are now implemented as inline x87
intrinsics when using -ffast-math.
* The ceil, floor, nearbyint, rint and trunc mathematical builtins
(and their float and long double variants) are now implemented as
inline x87 intrinsics when using -ffast-math.
* The x87's fsincos instruction is now used automatically with
-ffast-math when calculating both the sin and cos of the same
argument.
* Instruction selection for multiplication and division by constants
has been improved.
IA-64
* Floating point division, integer division and sqrt are now inlined,
resulting in significant performance improvements on some codes.
MIPS
* Division by zero checks now use conditional traps if the target
processor supports them. This decreases code size by one word per
division operation. The old behavior (branch and break) can be
obtained either at configure time by passing --with-divide=breaks
to configure or at runtime by passing -mdivide-breaks to GCC.
* Support for MIPS64 paired-single instructions has been added. It is
enabled by -mpaired-single and can be accessed using both the
target-independent vector extensions and new MIPS-specific built-in
functions.
* Support for the MIPS-3D ASE has been added. It is enabled by
-mips3d and provides new MIPS-3D-specific built-in functions.
* The -mexplicit-relocs option now supports static n64 code (as is
used, for example, in 64-bit linux kernels). -mexplicit-relocs
should now be feature-complete and is enabled by default when GCC
is configured to use a compatible assembler.
* Support for the NEC VR4130 series has been added. This support
includes the use of VR-specific instructions and a new VR4130
scheduler. Full VR4130 support can be selected with -march=vr4130
while code for any ISA can be tuned for the VR4130 using
-mtune=vr4130. There is also a new -mvr4130-align option that
produces better schedules at the cost of increased code size.
* Support for the Broadcom SB-1 has been extended. There is now an
SB-1 scheduler as well as support for the SB-1-specific
paired-single instructions. Full SB-1 support can be selected with
-march=sb1 while code for any ISA can be optimized for the SB-1
using -mtune=sb1.
* The compiler can now work around errata in R4000, R4400, VR4120 and
VR4130 processors. These workarounds are enabled by -mfix-r4000,
-mfix-r4400, -mfix-vr4120 and -mfix-vr4130 respectively. The VR4120
and VR4130 workarounds need binutils 2.16 or above.
* IRIX shared libraries are now installed into the standard library
directories: o32 libraries go into lib/, n32 libraries go into
lib32/ and n64 libraries go into lib64/.
* The compiler supports a new -msym32 option. It can be used to
optimize n64 code in which all symbols are known to have 32-bit
values.
S/390 and zSeries
* New command-line options help to generate code intended to run in
an environment where stack space is restricted, e.g. Linux kernel
code:
+ -mwarn-framesize and -mwarn-dynamicstack trigger compile-time
warnings for single functions that require large or dynamic
stack frames.
+ -mstack-size and -mstack-guard generate code that checks for
stack overflow at run time.
+ -mpacked-stack generates code that reduces the stack frame
size of many functions by reusing unneeded parts of the stack
bias area.
* The -msoft-float option now ensures that generated code never
accesses floating point registers.
* The s390x-ibm-tpf target now fully supports C++, including
exceptions and threads.
* Various changes to improve performance of the generated code have
been implemented, including:
+ GCC now uses sibling calls where possible.
+ Condition code handling has been optimized, allowing GCC to
omit redundant comparisons in certain cases.
+ The cost function guiding many optimizations has been refined
to more accurately represent the z900 and z990 processors.
+ The ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL WITH BORROW
instructions are now used to avoid conditional branches in
certain cases.
+ The back end now uses the LEGITIMIZE_RELOAD_ADDRESS feature to
optimize address arithmetic required to access large stack
frames.
+ GCC now makes more efficient use of memory-to-memory type
instructions (MVC, CLC, ...).
+ More precise tracking of special register use allows better
instruction scheduling, in particular of the function prologue
and epilogue sequences.
+ The Java front end now generates inline code to implement
integer division, instead of calling library routines.
SPARC
* The options -mv8, -msparclite, -mcypress, -msupersparc, -mf930 and
-mf934 have been removed. They have been replaced with -mcpu=xxx.
* The internal model used to estimate the relative cost of each
instruction has been updated. It is expected to give better results
on recent UltraSPARC processors.
* Code generation for function prologues and epilogues has been
improved, resulting in better scheduling and allowing multiple exit
points in functions.
* Support for Sun's Visual Instruction Set (VIS) has been enhanced.
It is enabled by -mvis and provides new built-in functions for VIS
instructions on UltraSPARC processors.
* The option -mapp-regs has been turned on by default on Solaris too.
NetWare
* Novell NetWare (on ix86, no other hardware platform was ever really
supported by this OS) has been re-enabled and the ABI supported by
GCC has been brought into sync with that of MetroWerks CodeWarrior
(the ABI previously supported was that of some Unix systems, which
NetWare never tried to support).
Obsolete Systems
Support for a number of older systems has been declared obsolete in GCC
4.0. Unless there is activity to revive them, the next release of GCC
will have their sources permanently removed.
All GCC ports for the following processor architectures have been
declared obsolete:
* Intel i860
* Ubicom IP2022
* National Semiconductor NS32K
* Texas Instruments TMS320C[34]x
Also, those for some individual systems have been obsoleted:
* SPARC family
+ SPARClite-based systems (sparclite-*-coff, sparclite-*-elf,
sparc86x-*-elf)
+ OpenBSD 32-bit (sparc-*-openbsd*)
Documentation improvements
Other significant improvements
* Location lists are now generated by default when compiling with
debug info and optimization. Location lists provide more accurate
debug info about locations of variables and they allow debugging
code compiled with -fomit-frame-pointer.
* The -fvisibility option has been added which allows the default ELF
visibility of all symbols to be set per compilation and the new
#pragma GCC visibility preprocessor command allows the setting of
default ELF visibility for a region of code. Using
-fvisibility=hidden especially in combination with the new
-fvisibility-inlines-hidden can yield substantial improvements in
output binary quality including avoiding PLT indirection overheads,
reduction of the exported symbol count by up to 60% (with resultant
improvements to link and load times), better scope for the
optimizer to improve code and up to a 20% reduction in binary size.
Using these options correctly yields a binary with a similar symbol
count to a Windows DLL.
Perhaps more importantly, this new feature finally allows (with
careful planning) complete avoidance of symbol clashes when
manually loading shared objects with RTLD_GLOBAL, thus finally
solving problems many projects such as python were forced to use
RTLD_LOCAL for (with its resulting issues for C++ correctness). You
can find more information about using these options at
[11]http://gcc.gnu.org/wiki/Visibility.
__________________________________________________________________
GCC 4.0.1
This is the [12]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.0.1 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
GCC 4.0.2
This is the [13]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.0.2 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
Unfortunately, due to a release engineering failure, this release has a
regression on Solaris that will affect some C++ programs. We suggest
that Solaris users apply a [14]patch that corrects the problem. Users
who do not wish to apply the patch should explicitly link C++ programs
with the -pthreads option, even if they do not use threads. This
problem has been corrected in the current 4.0 branch sources and will
not be present in GCC 4.0.3.
GCC 4.0.3
Starting with this release, the function getcontext is recognized by
the compiler as having the same semantics as the setjmp function. In
particular, the compiler will ensure that all registers are dead before
calling such a function and will emit a warning about the variables
that may be clobbered after the second return from the function.
GCC 4.0.4
This is the [15]list of problem reports (PRs) from GCC's bug tracking
system that are known to be fixed in the 4.0.4 release. This list might
not be complete (that is, it is possible that some PRs that have been
fixed are not listed here).
The 4.0.4 release is provided for those that require a high degree of
binary compatibility with previous 4.0.x releases. For most users, the
GCC team recommends that version 4.1.1 or later be used instead."
Please send FSF & GNU inquiries & questions to [16]gnu@gnu.org. There
are also [17]other ways to contact the FSF.
These pages are maintained by [18]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [19]GCC manuals. If that fails, the
[20]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [21]gcc@gnu.org or [22]gcc@gcc.gnu.org.
All of our lists have [23]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2009-01-25 [24]Valid XHTML 1.0
References
1. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4
2. http://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html
3. http://gcc.gnu.org/projects/tree-ssa/
4. http://gcc.gnu.org/projects/tree-ssa/vectorization.html
5. http://gcc.gnu.org/news/sms.html
6. http://people.redhat.com/drepper/dsohowto.pdf
7. http://gcc.gnu.org/gcc-4.0/changes.html#visibility
8. http://www.codesourcery.com/public/cxx-abi/
9. http://gcc.gnu.org/fortran/
10. http://gcc.gnu.org/install/
11. http://gcc.gnu.org/wiki/Visibility
12. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.1
13. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.2
14. http://gcc.gnu.org/ml/gcc-cvs/2005-09/msg00984.html
15. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.4
16. mailto:gnu@gnu.org
17. http://www.gnu.org/home.html#ContactInfo
18. http://gcc.gnu.org/about.html
19. http://gcc.gnu.org/onlinedocs/
20. mailto:gcc-help@gcc.gnu.org
21. mailto:gcc@gnu.org
22. mailto:gcc@gcc.gnu.org
23. http://gcc.gnu.org/lists.html
24. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-3.4/index.html
GCC 3.4 Release Series
May 26, 2006
The [1]GNU project and the GCC developers are pleased to announce the
release of GCC 3.4.6.
This release is a bug-fix release, containing fixes for regressions in
GCC 3.4.4 relative to previous releases of GCC. This is the last of the
3.4.x series.
The GCC 3.4 release series includes numerous [2]new features,
improvements, bug fixes, and other changes, thanks to an [3]amazing
group of volunteers.
Release History
GCC 3.4.6
March 6, 2006 ([4]changes)
GCC 3.4.5
November 30, 2005 ([5]changes)
GCC 3.4.4
May 18, 2005 ([6]changes)
GCC 3.4.3
November 4, 2004 ([7]changes)
GCC 3.4.2
September 6, 2004 ([8]changes)
GCC 3.4.1
July 1, 2004 ([9]changes)
GCC 3.4.0
April 18, 2004 ([10]changes)
References and Acknowledgements
GCC used to stand for the GNU C Compiler, but since the compiler
supports several other languages aside from C, it now stands for the
GNU Compiler Collection.
A list of [11]successful builds is updated as new information becomes
available.
The GCC developers would like to thank the numerous people that have
contributed new features, improvements, bug fixes, and other changes as
well as test results to GCC. This [12]amazing group of volunteers is
what makes GCC successful.
For additional information about GCC please refer to the [13]GCC
project web site or contact the [14]GCC development mailing list.
To obtain GCC please use [15]our mirror sites, or [16]our SVN server.
Please send FSF & GNU inquiries & questions to [17]gnu@gnu.org. There
are also [18]other ways to contact the FSF.
These pages are maintained by [19]the GCC team.
For questions related to the use of GCC, please consult these web
pages and the [20]GCC manuals. If that fails, the
[21]gcc-help@gcc.gnu.org mailing list might help.
Please send comments on these web pages and the development of GCC to
our developer mailing list at [22]gcc@gnu.org or [23]gcc@gcc.gnu.org.
All of our lists have [24]public archives.
Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110, USA.
Verbatim copying and distribution of this entire article is permitted
in any medium, provided this notice is preserved.
Last modified 2008-07-26 [25]Valid XHTML 1.0
References
1. http://www.gnu.org/
2. http://gcc.gnu.org/gcc-3.4/changes.html
3. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
4. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6
5. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.5
6. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.4
7. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.3
8. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.2
9. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.1
10. http://gcc.gnu.org/gcc-3.4/changes.html
11. http://gcc.gnu.org/gcc-3.4/buildstat.html
12. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
13. http://gcc.gnu.org/index.html
14. mailto:gcc@gcc.gnu.org
15. http://gcc.gnu.org/mirrors.html
16. http://gcc.gnu.org/svn.html
17. mailto:gnu@gnu.org
18. http://www.gnu.org/home.html#ContactInfo
19. http://gcc.gnu.org/about.html
20. http://gcc.gnu.org/onlinedocs/
21. mailto:gcc-help@gcc.gnu.org
22. mailto:gcc@gnu.org
23. mailto:gcc@gcc.gnu.org
24. http://gcc.gnu.org/lists.html
25. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-3.4/changes.html
GCC 3.4 Release Series
Changes, New Features, and Fixes
The final release in the 3.4 release series is [1]GCC 3.4.6. The series
is now closed.
GCC 3.4 has [2]many improvements in the C++ frontend. Before reporting
a bug, please make sure it's really GCC, and not your code, that is
broken.
Caveats
* GNU Make is now required to build GCC.
* With -nostdinc the preprocessor used to ignore both standard
include paths and include paths contained in environment variables.
It was neither documented nor intended that environment variable
paths be ignored, so this has been corrected.
* GCC no longer accepts the options -fvolatile, -fvolatile-global and
-fvolatile-static. It is unlikely that they worked correctly in any
3.x release.
* GCC no longer ships <varargs.h>. Use <stdarg.h> instead.
* Support for all the systems [3]obsoleted in GCC 3.3 has been
removed from GCC 3.4. See below for a [4]list of systems which are
obsoleted in this release.
* GCC now requires an ISO C90 (ANSI C89) C compiler to build. K&R C
compilers will not work.
* The implementation of the [5]MIPS ABIs has changed. As a result,
the code generated for certain MIPS targets will not be binary
compatible with earlier releases.
* In previous releases, the MIPS port had a fake "hilo" register with
the user-visible name accum. This register has been removed.
* The implementation of the [6]SPARC ABIs has changed. As a result,
the code generated will not be binary compatible with earlier
releases in certain cases.
* The configure option --enable-threads=pthreads has been removed;
use --enable-threads=posix instead, which should have the same
effect.
* Code size estimates used by inlining heuristics for C, Objective-C,
C++ and Java have been redesigned significantly. As a result the
parameters of -finline-insns, --param max-inline-insns-single and
--param max-inline-insns-auto need to be reconsidered.
* --param max-inline-slope and --param min-inline-insns have been
removed; they are not needed for the new bottom-up inlining
heuristics.
* The new unit-at-a-time compilation scheme has several compatibility
issues:
+ The order in which functions, variables, and top-level asm
statements are emitted may have changed. Code relying on some
particular ordering needs to be updated. The majority of such
top-level asm statements can be replaced by section
attributes.
+ Unreferenced static variables and functions are removed. This
may result in undefined references when an asm statement
refers to the variable/function directly. In that case either
the variable/function shall be listed in asm statement operand
or in the case of top-level asm statements the attribute used
shall be used to force function/variable to be always output
and considered as a possibly used by unknown code.
For variables the attribute is accepted only by GCC 3.4 and
newer, while for earlier versions it is sufficient to use
unused to silence warnings about the variables not being
referenced. To keep code portable across different GCC
versions, you can use appropriate preprocessor conditionals.
+ Static functions now can use non-standard passing conventions
that may break asm statements calling functions directly.
Again the attribute used shall be used to prevent this
behavior.
As a temporary workaround, -fno-unit-at-a-time can be used, but
this scheme may not be supported by future releases of GCC.
* GCC 3.4 automatically places zero-initialized variables in the .bss
section on some operating systems. Versions of GNU Emacs up to (and
including) 21.3 will not work correctly when using this
optimization; you can use -fno-zero-initialized-in-bss to disable
it.
* If GCC 3.4 is configured with --enable-threads=posix (the default
on most targets that support pthreads) then _REENTRANT will be
defined unconditionally by some libstdc++ headers. C++ code which
relies on that macro to detect whether multi-threaded code is being
compiled might change in meaning, possibly resulting in linker
errors for single-threaded programs. Affected users of [7]Boost
should compile single-threaded code with -DBOOST_DISABLE_THREADS.
See Bugzilla for [8]more information.
General Optimizer Improvements
* Usability of the profile feedback and coverage testing has been
improved.
+ Performance of profiled programs has been improved by faster
profile merging code.
+ Better use of the profile feedback for optimization (loop
unrolling and loop peeling).
+ File locking support allowing fork() calls and parallel runs
of profiled programs.
+ Coverage file format has been redesigned.
+ gcov coverage tool has been improved.
+ make profiledbootstrap available to build a faster compiler.
Experiments made on i386 hardware showed an 11% speedup on -O0
and a 7.5% speedup on -O2 compilation of a [9]large C++
testcase.
+ New value profiling pass enabled via -fprofile-values
+ New value profile transformations pass enabled via -fvpt aims
to optimize some code sequences by exploiting knowledge about
value ranges or other properties of the operands. At the
moment a conversion of expensive divisions into cheaper
operations has been implemented.
+ New -fprofile-generate and -fprofile-use command-line options
to simplify the use of profile feedback.
* A new unit-at-a-time compilation scheme for C, Objective-C, C++ and
Java which is enabled via -funit-at-a-time (and implied by -O2). In
this scheme a whole file is parsed first and optimized later. The
following basic inter-procedural optimizations are implemented:
+ Removal of unreachable functions and variables
+ Discovery of local functions (functions with static linkage
whose address is never taken)
+ On i386, these local functions use register parameter passing
conventions.
+ Reordering of functions in topological order of the call graph
to enable better propagation of optimizing hints (such as the
stack alignments needed by functions) in the back end.
+ Call graph based out-of-order inlining heuristics which allows
to limit overall compilation unit growth (--param
inline-unit-growth).
Overall, the unit-at-a-time scheme produces a 1.3% improvement for
the SPECint2000 benchmark on the i386 architecture (AMD Athlon
CPU).
* More realistic code size estimates used by inlining for C,
Objective-C, C++ and Java. The growth of large functions can now be
limited via --param large-function-insns and --param
large-function-growth.
* A new cfg-level loop optimizer pass replaces the old loop unrolling
pass and adds two other loop transformations -- loop peeling and
loop unswitching -- and also uses the profile feedback to limit