Work on Clang for pure GN build.

build/toolchain/linux/BUILD.gn

Index: build/toolchain/linux/BUILD.gn
diff --git a/build/toolchain/linux/BUILD.gn b/build/toolchain/linux/BUILD.gn
index 74d287fec689eece71a3270f5771895f76434e11..38f4b184cee5bfe65b4e30f702ed8bbf4e79fbe7 100644
--- a/build/toolchain/linux/BUILD.gn
+++ b/build/toolchain/linux/BUILD.gn
@@ -2,10 +2,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("../clang.gni")
-import("../goma.gni")
-import("../gcc_toolchain.gni")
 import("//build/config/sysroot.gni")
+import("//build/toolchain/clang.gni")
+import("//build/toolchain/gcc_toolchain.gni")
+import("//build/toolchain/goma.gni")
 
 if (is_gyp) {
   # Set the compilers for GYP to use. This logic is only relevant to GYP where
@@ -47,8 +47,6 @@ if (is_gyp) {
   }
 }
 
-# ARM --------------------------------------------------------------------------
-
 gcc_toolchain("arm") {

[Nico, 2014/01/29 18:45:48]

clang can target arm too fwiw (the same clang binary can code for various
architectures, the compiler binary - target code mapping isn't 1-1 like with
gcc)

   cc = "arm-linux-gnueabi-gcc"
   cxx = "arm-linux-gnueabi-g++"
@@ -59,11 +57,22 @@ gcc_toolchain("arm") {
   toolchain_os = "linux"
 }
 
-# 32-bit -----------------------------------------------------------------------
-
 gcc_toolchain("x86") {
-  cc = "gcc"
-  cxx = "g++"
+  if (is_clang) {
+    if (use_clang_type_profiler) {
+      prefix = rebase_path("//third_party/llvm-allocated-type/Linux_ia32/bin",
+                           ".", root_build_dir)
+    } else {
+      prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
+                           ".", root_build_dir)
+    }
+    cc = "$prefix/clang"
+    cxx = "$prefix/clang++"

[Nico, 2014/01/29 18:45:48]

Will this harmonize with use_goma=1?

[brettw, 2014/01/30 00:24:03]

No, I haven't looked at Goma yet.

+  } else {
+    cc = "gcc"
+    cxx = "g++"
+  }
+
   ar = "ar"
   ld = cxx
 
@@ -72,8 +81,21 @@ gcc_toolchain("x86") {
 }
 
 gcc_toolchain("x64") {
-  cc = "gcc"
-  cxx = "g++"
+  if (is_clang) {
+    if (use_clang_type_profiler) {
+      prefix = rebase_path("//third_party/llvm-allocated-type/Linux_x64/bin",
+                           ".", root_build_dir)
+    } else {
+      prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
+                           ".", root_build_dir)
+    }
+    cc = "$prefix/clang"
+    cxx = "$prefix/clang++"
+  } else {
+    cc = "gcc"
+    cxx = "g++"
+  }
+
   ar = "ar"
   ld = cxx
 
@@ -81,8 +103,6 @@ gcc_toolchain("x64") {
   toolchain_os = "linux"
 }
 
-# MIPS -----------------------------------------------------------------------
-
 gcc_toolchain("mipsel") {
   cc = "mipsel-linux-gnu-gcc"
   cxx = "mipsel-linux-gnu-g++"