| #!/usr/bin/python |
| # Copyright (c) 2012 The Native Client Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| # |
| # |
| # This is a thin wrapper for native LD. This is not meant to be |
| # used by the user, but is called from pnacl-translate. |
| # This implements the native linking part of translation. |
| # |
| # All inputs must be native objects or linker scripts. |
| # |
| # --pnacl-sb will cause the sandboxed LD to be used. |
| # The bulk of this file is logic to invoke the sandboxed translator. |
| |
| import os |
| import subprocess |
| |
| from driver_tools import CheckTranslatorPrerequisites, GetArch, ParseArgs, \ |
| Run, UnrecognizedOption |
| from driver_env import env |
| from driver_log import Log |
| import driver_tools |
| import elftools |
| import ldtools |
| import pathtools |
| |
| |
| EXTRA_ENV = { |
| 'INPUTS' : '', |
| 'OUTPUT' : '', |
| |
| # The INPUTS file coming from the llc translation step |
| 'LLC_TRANSLATED_FILE' : '', |
| # Number of separate modules used for multi-threaded translation. This should |
| # have been set by pnacl-translate, but default to 0 for checking. |
| 'SPLIT_MODULE' : '0', |
| 'USE_STDLIB': '1', |
| |
| # Upstream gold has the segment gap built in, but the gap can be modified |
| # when not using the IRT. The gap does need to be at least one bundle so the |
| # halt sled can be added for the TCB in case the segment ends up being a |
| # multiple of 64k. |
| # --eh-frame-hdr asks the linker to generate an .eh_frame_hdr section, |
| # which is a presorted list of registered frames. This section is |
| # used by libgcc_eh/libgcc_s to avoid doing the sort during runtime. |
| # http://www.airs.com/blog/archives/462 |
| # |
| # BE CAREFUL: anything added to LD_FLAGS should be synchronized with |
| # flags used by the in-browser translator. |
| # See: binutils/gold/nacl_file.cc |
| 'LD_FLAGS' : '-nostdlib ' + |
| # Only relevant for ARM where it suppresses a warning. |
| # Ignored for other archs. |
| '--no-fix-cortex-a8 ' + |
| '--eh-frame-hdr ' + |
| # Give an error if any TEXTRELs occur. |
| '-z text ' + |
| # Ensure we don't accidentally get READ_IMPLIES_EXEC |
| # behaviour when building Linux Non-SFI executables. |
| '-z noexecstack ' + |
| '--build-id ', |
| |
| 'SEARCH_DIRS' : '${SEARCH_DIRS_USER} ${SEARCH_DIRS_BUILTIN}', |
| 'SEARCH_DIRS_USER' : '', |
| 'SEARCH_DIRS_BUILTIN': '${USE_STDLIB ? ${LIBS_NATIVE_ARCH}/}', |
| |
| # Note: this is only used in the unsandboxed case |
| 'RUN_LD' : '${LD} ${LD_FLAGS} ${inputs} -o ${output}' |
| } |
| |
| def PassThrough(*args): |
| env.append('LD_FLAGS', *args) |
| |
| LDPatterns = [ |
| ( '-o(.+)', "env.set('OUTPUT', pathtools.normalize($0))"), |
| ( ('-o', '(.+)'), "env.set('OUTPUT', pathtools.normalize($0))"), |
| |
| ( '-nostdlib', "env.set('USE_STDLIB', '0')"), |
| |
| ( '-L(.+)', |
| "env.append('SEARCH_DIRS_USER', pathtools.normalize($0))"), |
| ( ('-L', '(.*)'), |
| "env.append('SEARCH_DIRS_USER', pathtools.normalize($0))"), |
| |
| # Note: we do not yet support all the combinations of flags which affect |
| # layout of the various sections and segments because the corner cases in gold |
| # may not all be worked out yet. They can be added (and tested!) as needed. |
| ( '(-static)', PassThrough), |
| ( '(-pie)', PassThrough), |
| |
| ( ('(-Ttext=.*)'), PassThrough), |
| ( ('(-Trodata=.*)'), PassThrough), |
| ( ('(-Ttext-segment=.*)'), PassThrough), |
| ( ('(-Trodata-segment=.*)'), PassThrough), |
| ( ('(--rosegment-gap=.*)'), PassThrough), |
| ( ('(--section-start)', '(.+)'),PassThrough), |
| ( ('(--section-start=.*)'), PassThrough), |
| ( ('(-e)','(.*)'), PassThrough), |
| ( '(--entry=.*)', PassThrough), |
| ( '(-M)', PassThrough), |
| ( '(-t)', PassThrough), |
| ( ('-y','(.*)'), PassThrough), |
| ( ('(-defsym)','(.*)'), PassThrough), |
| ( '(-defsym=.*)', PassThrough), |
| ( '-export-dynamic', PassThrough), |
| |
| ( '(--print-gc-sections)', PassThrough), |
| ( '(--gc-sections)', PassThrough), |
| ( '(--unresolved-symbols=.*)', PassThrough), |
| ( '(--dynamic-linker=.*)', PassThrough), |
| ( '(-g)', PassThrough), |
| ( '(--build-id(?:=.+)?)', PassThrough), |
| |
| ( '-melf_nacl', "env.set('ARCH', 'X8632')"), |
| ( ('-m','elf_nacl'), "env.set('ARCH', 'X8632')"), |
| ( '-melf64_nacl', "env.set('ARCH', 'X8664')"), |
| ( ('-m','elf64_nacl'), "env.set('ARCH', 'X8664')"), |
| ( '-marmelf_nacl', "env.set('ARCH', 'ARM')"), |
| ( ('-m','armelf_nacl'), "env.set('ARCH', 'ARM')"), |
| ( '-mmipselelf_nacl', "env.set('ARCH', 'MIPS32')"), |
| ( ('-m','mipselelf_nacl'), "env.set('ARCH', 'MIPS32')"), |
| |
| # Inputs and options that need to be kept in order |
| ( '(--no-as-needed)', "env.append('INPUTS', $0)"), |
| ( '(--as-needed)', "env.append('INPUTS', $0)"), |
| ( '(--start-group)', "env.append('INPUTS', $0)"), |
| ( '(--end-group)', "env.append('INPUTS', $0)"), |
| ( '(-Bstatic)', "env.append('INPUTS', $0)"), |
| ( '(-Bdynamic)', "env.append('INPUTS', $0)"), |
| # This is the file passed from llc during translation (used to be via shmem) |
| ( ('--llc-translated-file=(.*)'), "env.append('INPUTS', $0)\n" |
| "env.set('LLC_TRANSLATED_FILE', $0)"), |
| ( '-split-module=([0-9]+)', "env.set('SPLIT_MODULE', $0)"), |
| ( '(--(no-)?whole-archive)', "env.append('INPUTS', $0)"), |
| |
| ( '(-l.*)', "env.append('INPUTS', $0)"), |
| ( '(--undefined=.*)', "env.append('INPUTS', $0)"), |
| |
| ( '(-.*)', UnrecognizedOption), |
| ( '(.*)', "env.append('INPUTS', pathtools.normalize($0))"), |
| ] |
| |
| def RemoveInterpProgramHeader(filename): |
| headers = elftools.GetELFAndProgramHeaders(filename) |
| assert headers |
| ehdr, phdrs = headers |
| for i, phdr in enumerate(phdrs): |
| if phdr.type == elftools.ProgramHeader.PT_INTERP: |
| fp = open(filename, 'rb+') |
| fp.seek(ehdr.phoff + ehdr.phentsize * i) |
| # Zero this program header. Note PT_NULL is 0. |
| fp.write('\0' * ehdr.phentsize) |
| fp.close() |
| |
| def main(argv): |
| env.update(EXTRA_ENV) |
| |
| ParseArgs(argv, LDPatterns) |
| |
| GetArch(required=True) |
| inputs = env.get('INPUTS') |
| output = env.getone('OUTPUT') |
| |
| if output == '': |
| output = pathtools.normalize('a.out') |
| |
| # As we will modify the output file in-place for non-SFI, we output |
| # the file to a temporary file first and then rename it. Otherwise, |
| # build systems such as make assume the output file is ready even |
| # if the last build failed during the in-place update. |
| tmp_output = output + '.tmp' |
| |
| # Expand all parameters |
| # This resolves -lfoo into actual filenames, |
| # and expands linker scripts into command-line arguments. |
| inputs = ldtools.ExpandInputs(inputs, |
| env.get('SEARCH_DIRS'), |
| True, |
| ldtools.LibraryTypes.NATIVE) |
| |
| env.push() |
| env.set('inputs', *inputs) |
| env.set('output', tmp_output) |
| |
| if env.getbool('SANDBOXED'): |
| RunLDSandboxed() |
| else: |
| Run('${RUN_LD}') |
| |
| if env.getbool('NONSFI_NACL'): |
| # Remove PT_INTERP in non-SFI binaries as we never use host's |
| # dynamic linker/loader. |
| # |
| # This is necessary otherwise we get a statically linked |
| # executable that is not directly runnable by Linux, because Linux |
| # tries to load the non-existent file that PT_INTERP points to. |
| # |
| # This is fairly hacky. It would be better if the linker provided |
| # an option for omitting PT_INTERP (e.g. "--dynamic-linker ''"). |
| RemoveInterpProgramHeader(tmp_output) |
| if driver_tools.IsWindowsPython() and os.path.exists(output): |
| # On Windows (but not on Unix), the os.rename() call would fail if the |
| # output file already exists. |
| os.remove(output) |
| os.rename(tmp_output, output) |
| env.pop() |
| # only reached in case of no errors |
| return 0 |
| |
| def IsFlag(arg): |
| return arg.startswith('-') |
| |
| def RunLDSandboxed(): |
| if not env.getbool('USE_STDLIB'): |
| Log.Fatal('-nostdlib is not supported by the sandboxed translator') |
| CheckTranslatorPrerequisites() |
| # The "main" input file is the application's combined object file. |
| all_inputs = env.get('inputs') |
| |
| main_input = env.getone('LLC_TRANSLATED_FILE') |
| if not main_input: |
| Log.Fatal("Sandboxed LD requires one shm input file") |
| |
| outfile = env.getone('output') |
| |
| modules = int(env.getone('SPLIT_MODULE')) |
| assert modules >= 1 |
| first_mainfile = all_inputs.index(main_input) |
| first_extra = all_inputs.index(main_input) + modules |
| # Have a list of just the split module files. |
| llc_outputs = all_inputs[first_mainfile:first_extra] |
| # Have a list of everything else. |
| other_inputs = all_inputs[:first_mainfile] + all_inputs[first_extra:] |
| |
| native_libs_dirname = pathtools.tosys(GetNativeLibsDirname(other_inputs)) |
| command = [driver_tools.SelLdrCommand(), |
| '-a'] # Allow file access |
| driver_tools.AddListToEnv(command, 'NACL_IRT_PNACL_TRANSLATOR_LINK_INPUT', |
| llc_outputs) |
| command.extend([ |
| '-E', 'NACL_IRT_PNACL_TRANSLATOR_LINK_OUTPUT=%s ' % outfile, |
| '-E', 'NACL_IRT_OPEN_RESOURCE_BASE=%s' % native_libs_dirname, |
| '-E', 'NACL_IRT_OPEN_RESOURCE_REMAP=%s' |
| % 'libpnacl_irt_shim.a:libpnacl_irt_shim_dummy.a', |
| '--', '${LD_SB}']) |
| Run(' '.join(command), |
| # stdout/stderr will be automatically dumped |
| # upon failure |
| redirect_stderr=subprocess.PIPE, |
| redirect_stdout=subprocess.PIPE) |
| |
| |
| def GetNativeLibsDirname(other_inputs): |
| """Check that native libs have a common directory and return the directory.""" |
| dirname = None |
| for f in other_inputs: |
| if IsFlag(f): |
| continue |
| else: |
| if not pathtools.exists(f): |
| Log.Fatal("Unable to open '%s'", pathtools.touser(f)) |
| if dirname is None: |
| dirname = pathtools.dirname(f) |
| else: |
| if dirname != pathtools.dirname(f): |
| Log.Fatal('Need a common directory for native libs: %s != %s', |
| dirname, pathtools.dirname(f)) |
| if not dirname: |
| Log.Fatal('No native libraries found') |
| return dirname + '/' |
