Move goma/ccache logic to //build/toolchain/gcc_toolchain.gni

build/toolchain/gcc_toolchain.gni

 # 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("//build/config/nacl/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/toolchain/ccache.gni")
+import("//build/toolchain/goma.gni")
 import("//build/toolchain/toolchain.gni")
 
 # This value will be inherited in the toolchain below.
 concurrent_links = exec_script("get_concurrent_links.py", [], "value")
 
 # This template defines a toolchain for something that works like gcc
 # (including clang).
 #
 # It requires the following variables specifying the executables to run:
 #  - cc
@@ skipping 60 matching lines @@
   toolchain(target_name) {
     assert(defined(invoker.cc), "gcc_toolchain() must specify a \"cc\" value")
     assert(defined(invoker.cxx), "gcc_toolchain() must specify a \"cxx\" value")
     assert(defined(invoker.ar), "gcc_toolchain() must specify a \"ar\" value")
     assert(defined(invoker.ld), "gcc_toolchain() must specify a \"ld\" value")
     assert(defined(invoker.toolchain_cpu),
            "gcc_toolchain() must specify a \"toolchain_cpu\"")
     assert(defined(invoker.toolchain_os),
            "gcc_toolchain() must specify a \"toolchain_os\"")
 
+    # Allow toolchains to avoid ccache/goma explicitly

[brettw, 2015/09/24 19:35:56]

The phrasing of this comment seems weird to me, since I don't really see it as
opt-out. I'd say we don't need a comment here, but you should document the new
use_ccache and use_goma variables in the comment above the template above.

[Dirk Pranke, 2015/09/24 19:41:08]

I'm not sure I understand you; we still want the command line arg use_goma to
override 
things for the default toolchains; are you suggesting that we should modify,
e.g., clang_x64's toolchain_args
to say use_goma = use_goma ?

[tsniatowski, 2015/09/24 19:48:26]

This wouldn't do anything. As I understand it the setting would simply be better
documented as "Set to false to avoid using ccache/goma even if requested
globally" near where other invoker-settable variables are listed.

+    if (defined(invoker.use_ccache)) {
+      use_ccache = invoker.use_ccache
+    }
+    if (defined(invoker.use_goma)) {
+      use_goma = invoker.use_goma
+    }
+    if (use_goma) {
+      assert(!use_ccache, "Goma and ccache can't be used together.")
+      compiler_prefix = "$goma_dir/gomacc "
+    } else if (use_ccache) {
+      compiler_prefix = "ccache "
+    } else {
+      compiler_prefix = ""
+    }
+
     # This define changes when the toolchain changes, forcing a rebuild.
     # Nothing should ever use this define.
     if (defined(invoker.rebuild_define)) {
       rebuild_string = "-D" + invoker.rebuild_define + " "
     } else {
       rebuild_string = ""
     }
 
-    # We can't do string interpolation ($ in strings) on things with dots in
-    # them. To allow us to use $cc below, for example, we create copies of
-    # these values in our scope.
-    cc = invoker.cc
-    cxx = invoker.cxx
+    cc = compiler_prefix + invoker.cc
+    cxx = compiler_prefix + invoker.cxx
     ar = invoker.ar
     ld = invoker.ld
     if (defined(invoker.readelf)) {
       readelf = invoker.readelf
     } else {
       readelf = "readelf"
     }
     if (defined(invoker.nm)) {
       nm = invoker.nm
     } else {
@@ skipping 222 matching lines @@
         is_lsan = false
         is_msan = false
         is_syzyasan = false
         is_tsan = false
       }
     }
 
     forward_variables_from(invoker, [ "deps" ])
   }
 }