Put GN object files in subdir based on the label.

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")
 
@@ skipping 156 matching lines @@
     if (defined(invoker.solink_libs_section_postfix)) {
       solink_libs_section_postfix = invoker.solink_libs_section_postfix
     } else {
       solink_libs_section_postfix = ""
     }
 
     # These library switches can apply to all tools below.
     lib_switch = "-l"
     lib_dir_switch = "-L"
 
+    # Object files go in this directory.
+    object_subdir = "{{target_out_dir}}/{{label_name}}"
+
     tool("cc") {
       depfile = "{{output}}.d"
       command = "$cc -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "CC {{output}}"
       outputs = [
-        "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
+        "$object_subdir/{{source_name_part}}.o",
       ]
     }
 
     tool("cxx") {
       depfile = "{{output}}.d"
       command = "$cxx -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "CXX {{output}}"
       outputs = [
-        "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
+        "$object_subdir/{{source_name_part}}.o",
       ]
     }
 
     tool("asm") {
       # For GCC we can just use the C compiler to compile assembly.
       depfile = "{{output}}.d"
       command = "$cc -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{asmflags}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "ASM {{output}}"
       outputs = [
-        "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
+        "$object_subdir/{{source_name_part}}.o",
       ]
     }
 
     tool("alink") {
       rspfile = "{{output}}.rsp"
       arflags = ""
       if (is_cfi && invoker.toolchain_os != "nacl") {
         gold_plugin_path = rebase_path(
                 "//third_party/llvm-build/Release+Asserts/lib/LLVMgold.so",
                 root_build_dir)
@@ skipping 228 matching lines @@
     nm = "${toolprefix}nm"
 
     forward_variables_from(invoker,
                            [
                              "toolchain_cpu",
                              "toolchain_os",
                              "use_gold",
                            ])
   }
 }