PNaCl dynamic loading: Extend pnacl-translate to be able to translate PSOs

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 multiprocessing
 import os
 import pathtools
 from driver_env import env
 from driver_log import Log
 from driver_temps import TempFiles
 
 import subprocess
 
 EXTRA_ENV = {
-  'PIC': '${NONSFI_NACL}',
+  'TRANSLATE_PSO': '0',
+  'PIC': '${NONSFI_NACL || TRANSLATE_PSO ? 1 : 0}',
 
   # Determine if we should build nexes compatible with the IRT
   'USE_IRT' : '1',
 
   # Allow zero-cost C++ exception handling in the pexe, which is not
   # supported by PNaCl's stable ABI.
   'ALLOW_ZEROCOST_CXX_EH' : '0',
 
   # Use the IRT shim by default. This can be disabled with an explicit
   # flag (--noirtshim) or via -nostdlib.
@@ skipping 26 matching lines @@
   # and pnacl/driver/nativeld.py that will fall back to
   # libpnacl_irt_shim_dummy.a if libpnacl_irt_shim.a does not exist.
   'LD_ARGS_IRT_SHIM': '-l:libpnacl_irt_shim.a',
   'LD_ARGS_IRT_SHIM_DUMMY': '-l:libpnacl_irt_shim_dummy.a',
   # In addition to specifying the entry point, we also specify an undefined
   # reference to _start, which is called by the shim's entry function,
   # __pnacl_wrapper_start. _start normally comes from libnacl and will be in
   # the pexe, however for the IRT it comes from irt_entry.c and when linking it
   # using native object files, this reference is required to make sure it gets
   # pulled in from the archive.
-  'LD_ARGS_ENTRY': '${NONSFI_NACL && !USE_IRT '
-                   '  ? --entry=__pnacl_start_linux : --entry=__pnacl_start} '
-                   '--undefined=_start',
+  'LD_ARGS_ENTRY':
+      '${TRANSLATE_PSO ? --entry=__pnacl_pso_root : '
+      '  ${NONSFI_NACL && !USE_IRT '
+      '    ? --entry=__pnacl_start_linux : --entry=__pnacl_start} '
+      '  --undefined=_start}',
 
   'CRTBEGIN': '${ALLOW_ZEROCOST_CXX_EH ? -l:crtbegin_for_eh.o : -l:crtbegin.o}',
   'CRTEND': '-l:crtend.o',
 
   'LD_ARGS_nostdlib': '-nostdlib ${ld_inputs}',
 
   # These are just the dependencies in the native link.
   'LD_ARGS_normal':
-    '${CRTBEGIN} ${ld_inputs} ' +
+    '${!TRANSLATE_PSO ? ${CRTBEGIN}} ' +
+    '${ld_inputs} ' +
     '${USE_IRT_SHIM ? ${LD_ARGS_IRT_SHIM} : ${LD_ARGS_IRT_SHIM_DUMMY}} ' +
     '--start-group ' +
     '${USE_DEFAULTLIBS ? ${DEFAULTLIBS}} ' +
     '--end-group ' +
     '${CRTEND}',
 
   'DEFAULTLIBS': '${ALLOW_ZEROCOST_CXX_EH ? -l:libgcc_eh.a} ' +
                  '-l:libgcc.a -l:libcrt_platform.a ',
 
   # BE CAREFUL: anything added here can introduce skew between
@@ skipping 44 matching lines @@
   # use up to 4 modules if there are enough cores. If the user overrides,
   # use as many modules as specified (which could be only 1).
   'SPLIT_MODULE' : '0',
 }
 
 
 TranslatorPatterns = [
   ( '-o(.+)',          "env.set('OUTPUT', pathtools.normalize($0))"),
   ( ('-o', '(.+)'),    "env.set('OUTPUT', pathtools.normalize($0))"),
 
+  ( '-pso',            "env.set('TRANSLATE_PSO', '1')"),
+
   ( '-S',              "env.set('OUTPUT_TYPE', 's')"), # Stop at .s
   ( '-c',              "env.set('OUTPUT_TYPE', 'o')"), # Stop at .o
 
   # Expose a very limited set of llc flags.
   # BE CAREFUL: anything added here can introduce skew between
   # the pnacl-translate commandline tool and the in-browser translator.
   # See: llvm/tools/pnacl-llc/srpc_main.cpp and
   # chromium/src/ppapi/native_client/src/trusted/plugin/pnacl_options.cc
   ( '(-sfi-.+)',        "env.append('LLC_FLAGS_EXTRA', $0)"),
   ( '(-mtls-use-call)', "env.append('LLC_FLAGS_EXTRA', $0)"),
@@ skipping 95 matching lines @@
   env.set('LLC_FLAGS_ARCH', *llc_flags_map.get(env.getone('ARCH'), []))
   # When linking against a host OS's libc (such as Linux glibc), don't
   # use %gs:0 to read the thread pointer because that won't be
   # compatible with the libc's use of %gs:0.  Similarly, Non-SFI Mode
   # currently offers no optimized path for reading the thread pointer.
   if env.getone('TARGET_OS') != 'nacl' or env.getbool('NONSFI_NACL'):
     env.append('LLC_FLAGS_ARCH', '-mtls-use-call')
 
 
 def SetUpLinkOptions():
+  if env.getbool('TRANSLATE_PSO'):
+    # Using "-pie" rather than "-shared" has the effect of suppressing the
+    # creation of a PLT and R_*_JUMP_SLOT relocations, which come from the
+    # external symbol references that multi-threaded translation produces.
+    env.append('LD_FLAGS', '-pie')
+    return
+
   if env.getbool('NONSFI_NACL'):
     # "_begin" allows a PIE to find its load address in order to apply
     # dynamic relocations.
     env.append('LD_FLAGS', '-defsym=_begin=0')
     if env.getbool('USE_IRT'):
       env.append('LD_FLAGS', '-pie')
     else:
       # Note that we really want to use "-pie" for this case, but it
       # currently adds a PT_INTERP header to the executable that we don't
       # want because it stops the executable from being loadable by Linux.
@@ skipping 247 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.
 """