commit 36856f3f1905d41107358a9ed9081a244754c1d5
author Derek Bruening <bruening@google.com> Fri Jun 26 16:53:51 2020
committer GitHub <noreply@github.com> Fri Jun 26 16:53:51 2020
tree 71190b395c042911032b465212ad370a17dfcafb
parent 8da4e78f215c745e946ce9a3e6121efd5838fd94

i#1684 xarch-IR: Support separate host and target arch (#4325)

Adds support for building with different host and target
architectures.  The goal is to support running drdisas, drdecode,
drraw2trace, and drcachesim trace analyzers on one host machine while
targeting recorded bytes or traces from a different type of machine:
e.g., processing aarch64 traces on an x86_64 machine.  The goal is
*not* to turn DR into a cross-ISA binary translator: we only support
standalone mode here, not full DR managed mode.  Long-term it would be
nicer to split out the DR standalone mode interfaces into separate
libraries but that is beyond the scope of the current work.

Adds a top-level CMake option variable "TARGET_ARCH" which defaults to
CMAKE_SYSTEM_PROCESSOR but can be set to a different value.  The
regular arch variables/defines X86, AARCH64, and ARM are set from
TARGET_ARCH, while new values DR_HOST_{X86,AARCH64,ARM} are set for
the host.

Uses a target-centric approach, where the bulk of the code is built
targeting the TARGET_ARCH, with only assembly code and other limited code
using the DR_HOST_* arch.  This limits the scope of the code changes as
compared to the opposite host-centric approach.  A new define
DR_HOST_NOT_TARGET is used to simply disable cases where the host and
target are intertwined and difficult to easily separate, such as TLS
handling and assembly code used for application execution (such as
icache_op_isb_asm).

The key code changed to use DR_HOST_* includes:
+ *.asm files
+ arch_exports.h inline asm for atomics and other key utilities
+ system call defines (we don't want to have our raw syscall wrappers running
  incorrect syscall numbers: we'll end up with fork bombs or other madness)
+ injection code
+ data section setup
+ drsyms libraries

Code using built-in __*__ arch defines is changed to use our defines:
+ sigcontext.h, which is also augmented for some missing AArch64 types
+ x86_code_test.c

Code reading ELF headers is relaxed to allow *any* arch of the same
bitwdith (i#1345 prevents different bitwidth), since we need the host for
standalone init code but the target for raw2trace module mapping.

Nearly all tests are disabled not just from running but also from
building for simplicity, to reduce code changes here.  Some api.* decoder
tests, drdisas, and the altbin test for drcachesim post-processing and
analysis are enbabled in host!=target builds.
Tests are disabled by using a macro to set up the tests and shifting all
the setup code prior to the tests themselves, allowing a return() to skip
over the bulk of the tests to avoid a giant if().

Only Linux host-x86_64-target-aarch64 is explicitly tested and enabled
here.  Adding the inverse, and adding host-i386-target-arm32, should not be
much work, mostly with compiler flags, but will be done separately.  Adding
Windows support is also separated out as it requires a number of changes
for compiler problems with aarch64 code.

Adds a new host-x86_64-target-aarch64 build to runsuite.cmake, allocated to
a new Travis job to avoid slowing down the current jobs.

Issue: #1684, #4318, #1345