PNaCl: Allow translator to produce an unsandboxed, native executable

pnacl/driver/pnacl-translate.py

 #!/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.
 #
 # IMPORTANT NOTE: If you make local mods to this file, you must run:
 #   %  pnacl/build.sh driver
 # in order for them to take effect in the scons build.  This command
 # updates the copy in the toolchain/ tree.
 #
 
 import driver_tools
 import filetype
 import ldtools
+import os
 import pathtools
 import shutil
 from driver_env import env
 from driver_log import Log, TempFiles
 
 import re
 import subprocess
 
 EXTRA_ENV = {
   'PIC'           : '0',
@@ skipping 65 matching lines @@
     '${CRTEND}',
 
   'DEFAULTLIBS': '${ALLOW_CXX_EXCEPTIONS ? ' +
                  '${LIBGCC_EH}} -l:libgcc.a -l:libcrt_platform.a ',
 
   'TRIPLE'      : '${TRIPLE_%ARCH%}',
   'TRIPLE_ARM'  : 'armv7a-none-nacl-gnueabi',
   'TRIPLE_X8632': 'i686-none-nacl-gnu',
   'TRIPLE_X8664': 'x86_64-none-nacl-gnu',
   'TRIPLE_MIPS32': 'mipsel-none-nacl-gnu',
+  'TRIPLE_LINUX_X8632': 'i686-linux-gnu',
 
   'LLC_FLAGS_COMMON': '${PIC ? -relocation-model=pic} ' +
                       #  -force-tls-non-pic makes the code generator (llc)
                       # do the work that would otherwise be done by
                       # linker rewrites which are quite messy in the nacl
                       # case and hence have not been implemented in gold
                       '${PIC && !SHARED ? -force-tls-non-pic} ' +
                       # this translates the pexe one function at a time
                       # which is also what the streaming translation does
                       '-reduce-memory-footprint',
 
 
   'LLC_FLAGS_ARM'    :
     ('-arm-reserve-r9 -sfi-disable-cp ' +
      '-sfi-load -sfi-store -sfi-stack -sfi-branch -sfi-data ' +
      '-no-inline-jumptables -float-abi=hard -mattr=+neon'),
 
   'LLC_FLAGS_X8632' : '',
   'LLC_FLAGS_X8664' : '',
 
   'LLC_FLAGS_MIPS32': '-sfi-load -sfi-store -sfi-stack -sfi-branch -sfi-data',
 
+  # When linking against Linux glibc, don't use %gs:0 to read the
+  # thread pointer because that's not compatible with glibc's use of
+  # %gs.
+  'LLC_FLAGS_LINUX_X8632' : '-mtls-use-call',
+
   # LLC flags which set the target and output type.
   'LLC_FLAGS_TARGET' : '-mtriple=${TRIPLE} -filetype=${outfiletype}',
 
   # Append additional non-default flags here.
   'LLC_FLAGS_EXTRA' : '${FAST_TRANSLATION ? ${LLC_FLAGS_FAST}} ' +
                       '${#OPT_LEVEL ? -O${OPT_LEVEL}} ' +
                       '${OPT_LEVEL == 0 ? -disable-fp-elim}',
 
   # Opt level from command line (if any)
   'OPT_LEVEL' : '',
 
   # faster translation == slower code
-  'LLC_FLAGS_FAST' : '${LLC_FLAGS_FAST_%ARCH%}',
+  'LLC_FLAGS_FAST' : '${LLC_FLAGS_FAST_%ARCH%}'
+                     # This, surprisingly, makes a measurable difference
+                     ' -tail-merge-threshold=20',
 
-  'LLC_FLAGS_FAST_X8632': '-O0 ' +
-                          # This, surprisingly, makes a measurable difference
-                          '-tail-merge-threshold=20',
-  'LLC_FLAGS_FAST_X8664': '-O0 ' +
-                          '-tail-merge-threshold=20',
-  'LLC_FLAGS_FAST_ARM':   '-O0 ' +
-                          '-tail-merge-threshold=20',
-  'LLC_FLAGS_FAST_MIPS32': '-fast-isel -tail-merge-threshold=20',
+  'LLC_FLAGS_FAST_X8632': '-O0 ',
+  'LLC_FLAGS_FAST_X8664': '-O0 ',
+  'LLC_FLAGS_FAST_ARM':   '-O0 ',
+  'LLC_FLAGS_FAST_MIPS32': '-fast-isel',
+  'LLC_FLAGS_FAST_LINUX_X8632': '-O0',
 
   'LLC_FLAGS': '${LLC_FLAGS_TARGET} ${LLC_FLAGS_COMMON} ${LLC_FLAGS_%ARCH%} ' +
                '${LLC_FLAGS_EXTRA}',
 
   # CPU that is representative of baseline feature requirements for NaCl
   # and/or chrome.  We may want to make this more like "-mtune"
   # by specifying both "-mcpu=X" and "-mattr=+feat1,-feat2,...".
   # Note: this may be different from the in-browser translator, which may
   # do auto feature detection based on CPUID, but constrained by what is
   # accepted by NaCl validators.
   'LLC_MCPU'        : '-mcpu=${LLC_MCPU_%ARCH%}',
   'LLC_MCPU_ARM'    : 'cortex-a9',
   'LLC_MCPU_X8632'  : 'pentium4',
   'LLC_MCPU_X8664'  : 'core2',
   'LLC_MCPU_MIPS32' : 'mips32r2',
+  'LLC_MCPU_LINUX_X8632' : '${LLC_MCPU_X8632}',
 
   # Note: this is only used in the unsandboxed case
   'RUN_LLC'       : '${LLVM_PNACL_LLC} ${LLC_FLAGS} ${LLC_MCPU} '
                     '${input} -o ${output} ',
   # Rate in bits/sec to stream the bitcode from sel_universal over SRPC
   # for testing. Defaults to 1Gbps (effectively unlimited).
   'BITCODE_STREAM_RATE' : '1000000000',
 }
 
 
@@ skipping 130 matching lines @@
   if env.getbool('STATIC'):
     output_type = 'nexe'
   else:
     # Until we stabilize the ABI for shared libraries,
     # assume that pnacl-translate only handles pexes -> nexes,
     # to avoid a dependency on bitcode metadata.
     output_type = 'nexe'
     env.set('STATIC', '1')
 
   assert output_type in ('so','nexe')
-  RunLD(ofile, output)
+  if env.getone('ARCH') == 'LINUX_X8632':
+    RunHostLD(ofile, output)
+  else:
+    RunLD(ofile, output)
   return 0
 
 def RunAS(infile, outfile):
   driver_tools.RunDriver('as', [infile, '-o', outfile])
 
 def ListReplace(items, old, new):
   ret = []
   for k in items:
     if k == old:
       ret.append(new)
@@ skipping 61 matching lines @@
     inputs.remove('__BITCODE__')
     inputs = ['--llc-translated-file=' + infile] + inputs
   ToggleDefaultCommandlineLD(inputs, infile)
   env.set('ld_inputs', *inputs)
   args = env.get('LD_ARGS') + ['-o', outfile]
   if not env.getbool('SHARED') and env.getbool('USE_STDLIB'):
     args += env.get('LD_ARGS_ENTRY')
   args += env.get('LD_FLAGS')
   driver_tools.RunDriver('nativeld', args)
 
+def RunHostLD(infile, outfile):
+  driver_tools.Run(['objcopy', '--redefine-sym', '_start=_user_start', infile])
+  lib_dir = env.getone('BASE_LIB_NATIVE') + 'linux-x86-32'
+  driver_tools.Run(['gcc', '-m32', infile,
+                    os.path.join(lib_dir, 'unsandboxed_irt.o'),
+                    '-o', outfile])
+
 def RunLLC(infile, outfile, outfiletype):
   env.push()
   env.setmany(input=infile, output=outfile, outfiletype=outfiletype)
   if env.getbool('SANDBOXED'):
     is_shared, soname, needed = RunLLCSandboxed()
     # Ignore is_shared, soname, and needed for now, since we aren't
     # dealing with bitcode shared libraries.
     env.pop()
   else:
     args = ["${RUN_LLC}"]
@@ skipping 81 matching lines @@
 
 ADVANCED OPTIONS:
   -mattr=<+feat1,-feat2>  Toggle specific cpu features on and off.
   -mcpu=<cpu-name>        Target a specific cpu type.  Tunes code as well as
                           turns cpu features on and off.
   -S                      Generate native assembly only.
   -c                      Generate native object file only.
   --pnacl-sb              Use the translator which runs inside the NaCl sandbox.
   -O[0-3]                 Change translation-time optimization level.
 """