[coverage] Filter some files from instrumentation.

This filters test and third_party files to get a speed-up
when running tests and when collecting profile data.

BUG=chromium:568949
LOG=n
NOTRY=true

Review URL: https://codereview.chromium.org/1730543002

Cr-Commit-Position: refs/heads/master@{#34216}

build/coverage_wrapper.py

+#!/usr/bin/env python
+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# CC/CXX wrapper script that excludes certain file patterns from coverage
+# instrumentation.
+
+import re
+import subprocess
+import sys
+
+exclusions = [
+  'src/third_party',
+  'third_party',
+  'test',
+  'testing',
+]
+
+args = sys.argv[1:]
+text = ' '.join(sys.argv[2:])
+for exclusion in exclusions:
+  if re.search(r'\-o obj/%s[^ ]*\.o' % exclusion, text):
+    args.remove('-fprofile-arcs')
+    args.remove('-ftest-coverage')
+    break
+
+sys.exit(subprocess.check_call(args))

build/standalone.gypi

@@ -48,6 +48,12 @@
     'release_extra_cflags%': '',
     'variables': {
       'variables': {
+        # goma settings.
+        # 1 to use goma.
+        # If no gomadir is set, it uses the default gomadir.
+        'use_goma%': 0,
+        'gomadir%': '',
+
         'variables': {
           'conditions': [
             ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or \
@@ -70,12 +76,23 @@
 
         # Instrument for code coverage with gcov.
         'coverage%': 0,
+
+        'conditions': [
+          # Set default gomadir.
+          ['OS=="win"', {
+            'gomadir': 'c:\\goma\\goma-win',
+          }, {
+            'gomadir': '<!(/bin/echo -n ${HOME}/goma)',
+          }],
+        ],
       },
       'base_dir%': '<(base_dir)',
       'host_arch%': '<(host_arch)',
       'target_arch%': '<(target_arch)',
       'v8_target_arch%': '<(target_arch)',
       'coverage%': '<(coverage)',
+      'use_goma%': '<(use_goma)',
+      'gomadir%': '<(gomadir)',
       'asan%': 0,
       'lsan%': 0,
       'msan%': 0,
@@ -104,22 +121,10 @@
       # TODO(machenbach): Only configured for windows.
       'fastbuild%': 0,
 
-      # goma settings.
-      # 1 to use goma.
-      # If no gomadir is set, it uses the default gomadir.
-      'use_goma%': 0,
-      'gomadir%': '',
-
       # Check if valgrind directories are present.
       'has_valgrind%': '<!pymod_do_main(has_valgrind)',
 
       'conditions': [
-        # Set default gomadir.
-        ['OS=="win"', {
-          'gomadir': 'c:\\goma\\goma-win',
-        }, {
-          'gomadir': '<!(/bin/echo -n ${HOME}/goma)',
-        }],
         ['host_arch!="ppc" and host_arch!="ppc64" and host_arch!="ppc64le" and host_arch!="s390" and host_arch!="s390x" and \
           coverage==0', {
           'host_clang%': 1,
@@ -362,6 +367,23 @@
         'host_cc': '<!(which gcc)',
         'host_cxx': '<!(which g++)',
       }],
+      ['use_goma==1 and ("<(GENERATOR)"=="ninja" or clang==1)', {
+        'conditions': [
+          ['coverage==1', {
+            'cc_wrapper': '<(base_dir)/build/coverage_wrapper.py <(gomadir)/gomacc',
+          }, {
+            'cc_wrapper': '<(gomadir)/gomacc',
+          }],
+        ],
+      }, {
+        'conditions': [
+          ['coverage==1', {
+            'cc_wrapper': '<(base_dir)/build/coverage_wrapper.py',
+          }, {
+            'cc_wrapper': 0,
+          }],
+        ],
+      }],
     ],
     # Default ARM variable settings.
     'arm_version%': 'default',
@@ -1261,12 +1283,12 @@
     # TODO(yyanagisawa): supports GENERATOR==make
     #  make generator doesn't support CC_wrapper without CC
     #  in make_global_settings yet.
-    ['use_goma==1 and ("<(GENERATOR)"=="ninja" or clang==1)', {
+    ['cc_wrapper!=0', {
       'make_global_settings': [
-       ['CC_wrapper', '<(gomadir)/gomacc'],
-       ['CXX_wrapper', '<(gomadir)/gomacc'],
-       ['CC.host_wrapper', '<(gomadir)/gomacc'],
-       ['CXX.host_wrapper', '<(gomadir)/gomacc'],
+       ['CC_wrapper', '<(cc_wrapper)'],
+       ['CXX_wrapper', '<(cc_wrapper)'],
+       ['CC.host_wrapper', '<(cc_wrapper)'],
+       ['CXX.host_wrapper', '<(cc_wrapper)'],
       ],
     }],
     ['use_lto==1', {