PNaCl driver: Add libgcc to mixed native/bitcode links

pnacl/driver/pnacl-driver.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.
 #
@@ skipping 105 matching lines @@
   'ISYSTEM_CXX_include_paths' :
     '${BASE_USR}/include/c++/${STDLIB_IDIR} ' +
     '${BASE_USR}/include/c++/${STDLIB_IDIR}/arm-none-linux-gnueabi ' +
     '${BASE_USR}/include/c++/${STDLIB_IDIR}/backward',
 
 
   # Only propagate opt level to linker if explicitly set, so that the
   # linker will know if an opt level was explicitly set or not.
   'LD_FLAGS' : '${#OPT_LEVEL ? -O${OPT_LEVEL}} -static ' +
                '${PIC ? -fPIC} ${@AddPrefix:-L:SEARCH_DIRS} ' +
+               '${ALLOW_NATIVE ? -L${LIBS_NATIVE_ARCH}} ' +

[Mark Seaborn, 2014/08/09 07:11:51]

Might an alternative be to do this below:

if env.getbool('ALLOW_NATIVE'):
  env.append('LD_FLAGS', env.eval('-L${LIBS_NATIVE_ARCH}'))
  env.append('STDLIBS', '-lgcc')

In some of my recent changes to the driver scripts, I've been trying to move
away from the string interpolation that driver_env does, because the evaluation
order is a bit hard to understand.  (See SetUpArch and SetUpLinkOptions in
pnacl-translate.py.)

If you do that, the change is OK with me.  Otherwise I'd need to stare at the
driver_env.py change some more to understand it...

[Derek Schuff, 2014/08/11 17:54:17]

Done.

                '--pnacl-exceptions=${CXX_EH_MODE}',
 
   'SEARCH_DIRS' : '', # Directories specified using -L
 
   # Library Strings
   'EMITMODE'         : '${!USE_STDLIB ? nostdlib : static}',
 
   # This is setup so that LD_ARGS_xxx is evaluated lazily.
   'LD_ARGS' : '${LD_ARGS_%EMITMODE%}',
 
   # ${ld_inputs} signifies where to place the objects and libraries
   # provided on the command-line.
   'LD_ARGS_nostdlib': '-nostdlib ${ld_inputs}',
 
   'LD_ARGS_static':
     '${CXX_EH_MODE==zerocost ? -l:crt1_for_eh.x : -l:crt1.x} ' +
     '-l:crti.bc -l:crtbegin.bc '
     '${CXX_EH_MODE==sjlj ? -l:sjlj_eh_redirect.bc : '
       '${CXX_EH_MODE==none ? -l:unwind_stubs.bc}} ' +
     '${ld_inputs} ' +
     '--start-group ${STDLIBS} --end-group',
 
   'LLVM_PASSES_TO_DISABLE': '',
 
   # Flags for translating to native .o files.
   'TRANSLATE_FLAGS' : '-O${#OPT_LEVEL ? ${OPT_LEVEL} : 0}',
 
   'STDLIBS'   : '${DEFAULTLIBS ? '
-                '${LIBSTDCPP} ${LIBPTHREAD} ${LIBNACL} ${LIBC} ${LIBPNACLMM}}',
+                '${LIBSTDCPP} ${LIBPTHREAD} ${LIBNACL} ${LIBC} ${LIBPNACLMM} '
+                '${ALLOW_NATIVE ? ${NATIVELIBS}}}',
   'LIBSTDCPP' : '${IS_CXX ? -l${STDLIB_TRUNC} -lm }',
   'LIBC'      : '-lc',
   'LIBNACL'   : '-lnacl',
   'LIBPNACLMM': '-lpnaclmm',
   # Enabled/disabled by -pthreads
   'LIBPTHREAD': '${PTHREAD ? -lpthread}',
+  # For native/mixed links, also bring in the native libgcc to avoid link
+  # failure if pre-translated native code needs functions from it.
+  'NATIVELIBS': '-lgcc',
 
   # IS_CXX is set by pnacl-clang and pnacl-clang++ programmatically
   'CC' : '${IS_CXX ? ${CLANGXX} : ${CLANG}}',
   'RUN_CC': '${CC} -emit-llvm ${mode} ${CC_FLAGS} ' +
             '${@AddPrefix:-isystem :ISYSTEM} ' +
             '-x${typespec} "${infile}" -o ${output}',
 }
 
 def AddLLVMPassDisableFlag(*args):
   env.append('LLVM_PASSES_TO_DISABLE', *args)
@@ skipping 319 matching lines @@
       Run(env.get('CC') + env.get('CC_FLAGS'))
     return 0
 
   unmatched = env.get('UNMATCHED')
   if len(unmatched) > 0:
     UnrecognizedOption(*unmatched)
 
   # If -arch was given, we are compiling directly to native code
   compiling_to_native = GetArch() is not None
 
   if env.getbool('ALLOW_NATIVE') and not compiling_to_native:

[Mark Seaborn, 2014/08/09 07:11:51]

e.g. somewhere around here

[Derek Schuff, 2014/08/11 17:54:17]

Done.

     Log.Fatal("--pnacl-allow-native without -arch is not meaningful.")
 
   if not env.get('STDLIB'):
     # Default C++ Standard Library.
     SetStdLib('libc++')
 
   inputs = env.get('INPUTS')
   output = env.getone('OUTPUT')
 
   if len(inputs) == 0:
@@ skipping 273 matching lines @@
   -g                    Generate complete debug information.
   -gline-tables-only    Generate debug line-information only
                         (allowing for stack traces).
   -flimit-debug-info    Generate limited debug information.
   -save-temps           Keep intermediate compilation results.
   -v                    Verbose output / show commands.
   -h | --help           Show this help.
   --help-full           Show underlying clang driver's help message
                         (warning: not all options supported).
 """ % (tool)