Add support for 32-bit and 64-bit Windows compiles in GN.

build/toolchain/win/setup_toolchain.py

 # Copyright (c) 2013 The Chromium 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 os
 import re
 import sys
 
 def ExtractImportantEnvironment():
   """Extracts environment variables required for the toolchain from the
@@ skipping 17 matching lines @@
         result[envvar.upper()] = os.path.dirname(sys.executable) + \
             os.pathsep + os.environ[envvar]
       else:
         result[envvar.upper()] = os.environ[envvar]
   for required in ('SYSTEMROOT', 'TEMP', 'TMP'):
     if required not in result:
       raise Exception('Environment variable "%s" '
                       'required to be set to valid path' % required)
   return result
 
+
+# VC setup will add a path like this in 32-bit mode:
+#   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\BIN
+# And this in 64-bit mode:
+#   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\BIN\amd64
+# Note that in 64-bit it's duplicated but the 64-bit one comes first.
+#
+# What we get as the path when running this will depend on which VS setup
+# script you've run. The following two functions try to do this.
+
+# For 32-bit compiles remove anything that ends in "\VC\WIN\amd64".
+def FixupPath32(path):
+  find_64 = re.compile("VC\\\\BIN\\\\amd64\\\\*$", flags=re.IGNORECASE)
+
+  for i in range(len(path)):
+    if find_64.search(path[i]):
+      # Found 32-bit path, insert the 64-bit one immediately before it.
+      dir_64 = path[i].rstrip("\\")
+      dir_64 = dir_64[:len(dir_64) - 6]  # Trim off "\amd64".
+      path[i] = dir_64
+      break
+  return path
+
+# For 64-bit compiles, append anything ending in "\VC\BIN" with "\amd64" as
+# long as that thing isn't already in the list, and append it immediately
+# before the non-amd64-one.
+def FixupPath64(path):
+  find_32 = re.compile("VC\\\\BIN\\\\*$", flags=re.IGNORECASE)
+
+  for i in range(len(path)):
+    if find_32.search(path[i]):
+      # Found 32-bit path, insert the 64-bit one immediately before it.
+      dir_32 = path[i]
+      if dir_32[len(dir_32) - 1] == '\\':
+        dir_64 = dir_32 + "amd64"
+      else:
+        dir_64 = dir_32 + "\\amd64"
+      path.insert(i, dir_64)
+      break
+
+  return path
+
+
 def FormatAsEnvironmentBlock(envvar_dict):
   """Format as an 'environment block' directly suitable for CreateProcess.
   Briefly this is a list of key=value\0, terminated by an additional \0. See
   CreateProcess documentation for more details."""
   block = ''
   nul = '\0'
   for key, value in envvar_dict.iteritems():
     block += key + '=' + value + nul
   block += nul
   return block
 
 def CopyTool(source_path):
   """Copies the given tool to the current directory, including a warning not
   to edit it."""
   with open(source_path) as source_file:
     tool_source = source_file.readlines()
 
   # Add header and write it out to the current directory (which should be the
   # root build dir).
   with open("gyp-win-tool", 'w') as tool_file:
     tool_file.write(''.join([tool_source[0],
                              '# Generated by setup_toolchain.py do not edit.\n']
                             + tool_source[1:]))
 
+
 # Find the tool source, it's the first argument, and copy it.
 if len(sys.argv) != 2:
   print "Need one argument (win_tool source path)."
   sys.exit(1)
 CopyTool(sys.argv[1])
 
-# Write the environment file to the current directory.
-environ = FormatAsEnvironmentBlock(ExtractImportantEnvironment())
+important_env_vars = ExtractImportantEnvironment()
+path = important_env_vars["PATH"].split(";")
+
+important_env_vars["PATH"] = ";".join(FixupPath32(path))
+environ = FormatAsEnvironmentBlock(important_env_vars)
 with open('environment.x86', 'wb') as env_file:
   env_file.write(environ)
 
+important_env_vars["PATH"] = ";".join(FixupPath64(path))
+environ = FormatAsEnvironmentBlock(important_env_vars)
+with open('environment.x64', 'wb') as env_file:
+  env_file.write(environ)