Create a build_config header file.

SConstruct

Index: SConstruct
diff --git a/SConstruct b/SConstruct
index 609af9513043ec432fdf1f8fa1dd7907206b35ed..9a54ceda2f2def83471d4825d840a512d6b38cc1 100755
--- a/SConstruct
+++ b/SConstruct
@@ -2142,13 +2142,6 @@ that the given target requires that argument be given."""
 pre_base_env.AddMethod(GetAbsDirArg)
 
 
-pre_base_env.Append(
-    CPPDEFINES = [
-        ['NACL_BUILD_ARCH', '${BUILD_ARCHITECTURE}' ],
-        ['NACL_BUILD_SUBARCH', '${BUILD_SUBARCH}' ],
-        ],
-    )
-
 def MakeGTestEnv(env):
   # Create an environment to run unit tests using Gtest.
   gtest_env = env.Clone()
@@ -2450,10 +2443,6 @@ def MakeWindowsEnv(platform=None):
 
   windows_env.Append(
       CPPDEFINES = [
-          ['NACL_WINDOWS', '1'],
-          ['NACL_OSX', '0'],
-          ['NACL_LINUX', '0'],
-          ['NACL_ANDROID', '0'],
           ['_WIN32_WINNT', '0x0501'],
           ['__STDC_LIMIT_MACROS', '1'],
           ['NOMINMAX', '1'],
@@ -2467,7 +2456,12 @@ def MakeWindowsEnv(platform=None):
       LIBS = ['ws2_32', 'advapi32'],
       # TODO(bsy) remove 4355 once cross-repo
       # NACL_ALLOW_THIS_IN_INITIALIZER_LIST changes go in.
-      CCFLAGS = ['/EHsc', '/WX', '/wd4355', '/wd4800'],
+      CCFLAGS = ['/EHsc', '/WX', '/wd4355', '/wd4800',
+                  # build_config.h is injected as a header in all sources to

[Mark Seaborn, 2014/12/29 17:51:03]

Nit: indent by 1 space less

[teravest, 2014/12/29 22:29:28]

Done.

+                  # provide macro definitions for the operating system and
+                  # architecture. This is injected so it's never accidentally
+                  # omitted in source files.
+                 '/FI', '$SOURCE_ROOT/native_client/src/include/build_config.h']
   )
 
   # This linker option allows us to ensure our builds are compatible with
@@ -2523,6 +2517,10 @@ def MakeUnixLikeEnv(platform=None):
         '-fdiagnostics-show-option',
         '-fvisibility=hidden',
         '-fstack-protector',
+        # build_config.h is injected as a header in all sources to provide
+        # macro definitions for the operating system and architecture. This is
+        # injected so it's never accidentally omitted in source files.
+        '-include', '$SOURCE_ROOT/native_client/src/include/build_config.h',
         ] + werror_flags,
     # NOTE: pthread is only neeeded for libppNaClPlugin.so and on arm
     LIBS = ['pthread'],
@@ -2574,15 +2572,12 @@ def MakeMacEnv(platform=None):
       CCFLAGS=[subarch_flag, '-fPIC'],
       ASFLAGS=[subarch_flag],
       LINKFLAGS=[subarch_flag, '-fPIC'],
-      CPPDEFINES = [['NACL_WINDOWS', '0'],
-                    ['NACL_OSX', '1'],
-                    ['NACL_LINUX', '0'],
-                    ['NACL_ANDROID', '0'],
-                    # defining _DARWIN_C_SOURCE breaks 10.4
+      CPPDEFINES = [# defining _DARWIN_C_SOURCE breaks 10.4
                     #['_DARWIN_C_SOURCE', '1'],
                     #['__STDC_LIMIT_MACROS', '1']
                     ],
   )
+
   return mac_env
 
 (mac_debug_env, mac_optimized_env) = GenerateOptimizationLevels(MakeMacEnv())
@@ -2800,11 +2795,7 @@ def MakeGenericLinuxEnv(platform=None):
 
   # Prepend so we can disable warnings via Append
   linux_env.Prepend(
-      CPPDEFINES = [['NACL_WINDOWS', '0'],
-                    ['NACL_OSX', '0'],
-                    ['NACL_LINUX', '1'],
-                    ['NACL_ANDROID', '0'],
-                    ['_DEFAULT_SOURCE', '1'],
+      CPPDEFINES = [['_DEFAULT_SOURCE', '1'],
                     ['_BSD_SOURCE', '1'],
                     ['_POSIX_C_SOURCE', '199506'],
                     ['_XOPEN_SOURCE', '600'],
@@ -3118,6 +3109,8 @@ nacl_env.Append(
         ['NACL_OSX', '0'],
         ['NACL_LINUX', '0'],
         ['NACL_ANDROID', '0'],
+        ['NACL_BUILD_ARCH', '${BUILD_ARCHITECTURE}' ],

[Mark Seaborn, 2014/12/29 17:51:03]

Can you inject build_config.h for untrusted code too?

[teravest, 2014/12/29 22:29:28]

I'm getting some strange errors when doing so:
/usr/local/google/nacl_repo/native_client/src/include/build_config.h:10:49:
error: native_client/src/include/nacl_base.h: No such file or directory
/usr/local/google/nacl_repo/native_client/src/include/build_config.h:42:34:
error: "NACL_ARCH" is not defined
/usr/local/google/nacl_repo/native_client/src/include/build_config.h:42:43:
error: missing binary operator before token "("

I'm not sure why it can't find nacl_base.h in the untrusted build. There's
probably something tricky that has to happen with the includes, but I'd prefer
not to mess with the untrusted build too much.

[Mark Seaborn, 2015/01/02 04:18:31]

That is from the Scons build, right?

Does it fail like that on the trybots too, or did you only try it locally?  Can
you share the patch you tried so that I can try to debug it?

If you run Scons with --verbose, what is the command line that fails?  (I'm
wondering what "-I" arguments are passed.)

While it looks like you don't need to change the untrusted build for now (since
build_nexe.py sets NACL_BUILD_ARCH OK), I don't like mysteries like this getting
in the way of making things consistent. :-)

+        ['NACL_BUILD_SUBARCH', '${BUILD_SUBARCH}' ],
         ],
     )
 
@@ -3481,8 +3474,6 @@ def RawSyscallObjects(env, sources):
   raw_syscall_env.Append(
     CPPDEFINES = [
       ['USE_RAW_SYSCALLS', '1'],
-      ['NACL_BUILD_ARCH', '${BUILD_ARCHITECTURE}' ],
-      ['NACL_BUILD_SUBARCH', '${BUILD_SUBARCH}' ],
       ],
   )
   objects = []