Switch the nop pnacl x86-64 IRT shim to the real one generated from IDL.

SConstruct

 #! -*- python -*-
 # Copyright (c) 2011 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.
 
 import atexit
 import glob
 import os
 import platform
 import shutil
@@ skipping 3346 matching lines @@
 
 
 # The IRT-building environment was cloned from nacl_env, but it should
 # ignore the --nacl_glibc, nacl_pic=1 and bitcode=1 switches.
 # We have to reinstantiate the naclsdk.py magic after clearing those flags,
 # so it regenerates the tool paths right.
 # TODO(mcgrathr,bradnelson): could get cleaner if naclsdk.py got folded back in.
 nacl_irt_env.ClearBits('nacl_glibc')
 nacl_irt_env.ClearBits('nacl_pic')
 # For ARM: Can only build arm IRT w/ bitcode=1.
-# For x86-64: there are calling convention differences between pnacl and gcc.
-# http://code.google.com/p/nativeclient/issues/detail?id=1902
-# We can try building a pnacl-specific x86-64 IRT for now, but that means
-# that we aren't testing the same x86-64 IRT that comes with chrome.
-if not (nacl_irt_env.Bit('target_arm')
-        or nacl_irt_env.Bit('target_x86_64')):
+if not nacl_irt_env.Bit('target_arm'):
   nacl_irt_env.ClearBits('bitcode')
 nacl_irt_env.Tool('naclsdk')
 # These are unfortunately clobbered by running Tool, which
 # we needed to do to get the destination directory reset.
 # We want all the same values from nacl_env.
 nacl_irt_env.Replace(EXTRA_CFLAGS=nacl_env['EXTRA_CFLAGS'],
                      EXTRA_CXXFLAGS=nacl_env['EXTRA_CXXFLAGS'],
                      CCFLAGS=nacl_env['CCFLAGS'],
                      CFLAGS=nacl_env['CFLAGS'],
                      CXXFLAGS=nacl_env['CXXFLAGS'])
@@ skipping 73 matching lines @@
   lib_nodes = env.Replicate('${LIB_DIR}', nodes)
   PublishLibrary(env, lib_nodes)
   return lib_nodes
 nacl_env.AddMethod(NaClAddObject, 'AddObjectToSdk')
 
 # We want to do this for nacl_env when not under --nacl_glibc,
 # but for nacl_irt_env whether or not under --nacl_glibc, so
 # we do it separately for each after making nacl_irt_env and
 # clearing its Bit('nacl_glibc').
 def AddImplicitLibs(env):
+  implicit_libs = []
+
+  # Require the pnacl_irt_shim for pnacl x86-64.
+  # Use -B to have the compiler look for the fresh libpnacl_irt_shim.a.
+  if env.Bit('bitcode') and env.Bit('target_x86_64'):
+    implicit_libs += ['libpnacl_irt_shim.a']
+
   if not env.Bit('nacl_glibc'):
     # These are automatically linked in by the compiler, either directly
     # or via the linker script that is -lc.  In the non-glibc build, we
     # are the ones providing these files, so we need dependencies.
     # The ComponentProgram method (site_scons/site_tools/component_builders.py)
     # adds dependencies on env['IMPLICIT_LIBS'] if that's set.
     if env.Bit('bitcode'):
-      implicit_libs = ['libnacl.a']
+      implicit_libs += ['libnacl.a']
     else:
-      implicit_libs = ['crt1.o',
-                       'libnacl.a',
-                       'crti.o',
-                       'crtn.o']
+      implicit_libs += ['crt1.o',
+                        'libnacl.a',
+                        'crti.o',
+                        'crtn.o']
       # TODO(mcgrathr): multilib nonsense defeats -B!  figure out a better way.
       if GetPlatform('targetplatform') == 'x86-32':
         implicit_libs.append(os.path.join('32', 'crt1.o'))
+
+  if implicit_libs != []:
     env['IMPLICIT_LIBS'] = [env.File(os.path.join('${LIB_DIR}', file))
                             for file in implicit_libs]
     # The -B<dir>/ flag is necessary to tell gcc to look for crt[1in].o there.
     env.Prepend(LINKFLAGS=['-B${LIB_DIR}/'])
 
 AddImplicitLibs(nacl_env)
 AddImplicitLibs(nacl_irt_env)
 
 nacl_irt_env.Append(
     BUILD_SCONSCRIPTS = [
@@ skipping 268 matching lines @@
   nacl_env.ValidateSdk()
 
 if BROKEN_TEST_COUNT > 0:
   msg = "There are %d broken tests." % BROKEN_TEST_COUNT
   if GetOption('brief_comstr'):
     msg += " Add --verbose to the command line for more information."
   print msg
 
 # separate warnings from actual build output
 Banner('B U I L D - O U T P U T:')