Allow generating coverage reports for all unit-tests in the engine. (flutter/engine#7576)

DEPS

@@ -116,7 +116,7 @@ allowed_hosts = [
 ]
 
 deps = {
-  'src': 'https://github.com/flutter/buildroot.git' + '@' + 'ad6c0a07231e416bb3f96886b50778c70c491778',
+  'src': 'https://github.com/flutter/buildroot.git' + '@' + '85da9493a0584289b0b392ff2fb8d30e6b44e6a6',
 
    # Fuchsia compatibility
    #

engine/src/flutter/build/generate_coverage.py

@@ -0,0 +1,146 @@
+#!/usr/bin/env python
+#
+# Copyright 2013 The Flutter 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 sys
+import subprocess
+import os
+import argparse
+import errno
+import shutil
+
+def GetLLVMBinDirectory():
+  buildtool_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)), "../../buildtools")
+  platform_dir = ""
+  if sys.platform.startswith('linux'):
+    platform_dir = "linux-x64"
+  elif sys.platform == 'darwin':
+    platform_dir = "mac-x64"
+  else:
+    raise Exception("Unknown/Unsupported platform.")
+  llvm_bin_dir = os.path.abspath(os.path.join(buildtool_dir, platform_dir, "clang/bin"))
+  if not os.path.exists(llvm_bin_dir):
+    raise Exception("LLVM directory %s double not be located." % llvm_bin_dir)
+  return llvm_bin_dir
+
+
+def MakeDirs(new_dir):
+  """A wrapper around os.makedirs() that emulates "mkdir -p"."""
+  try:
+    os.makedirs(new_dir)
+  except OSError as e:
+    if e.errno != errno.EEXIST:
+      raise
+
+def RemoveIfExists(path):
+    if os.path.isdir(path) and not os.path.islink(path):
+        shutil.rmtree(path)
+    elif os.path.exists(path):
+        os.remove(path)
+
+def main():
+  parser = argparse.ArgumentParser();
+  
+  parser.add_argument('-t', '--tests', nargs='+', dest='tests',
+      required=True, help='The unit tests to run and gather coverage data on.')
+  parser.add_argument('-o', '--output', dest='output',
+      required=True, help='The output directory for coverage results.')
+  parser.add_argument('-f', '--format', type=str, choices=['all', 'html', 'summary'],
+      required=True, help='The type of coverage information to be displayed.')
+
+  args = parser.parse_args()
+
+  output = os.path.abspath(args.output)
+
+  MakeDirs(output)
+
+  generate_all_reports = args.format == "all"
+
+  raw_profiles = []
+  binaries = []
+
+  # Run all unit tests and collect raw profiles.
+  for test in args.tests:
+    absolute_test_path = os.path.abspath(test)
+    
+    if not os.path.exists(absolute_test_path):
+      print("Path %s does not exist." % absolute_test_path)
+      return -1
+
+    binaries.append(absolute_test_path)
+    
+    raw_profile = absolute_test_path + ".rawprofile"
+
+    RemoveIfExists(raw_profile)
+
+    print "Running test %s to gather profile." % os.path.basename(absolute_test_path)
+    
+    subprocess.check_call([absolute_test_path], shell=True, env={
+      "LLVM_PROFILE_FILE":  raw_profile
+    })
+
+    if not os.path.exists(raw_profile):
+      print("Could not find raw profile data for unit test run %s." % test)
+      print("Did you build with the --coverage flag?")
+      return -1
+
+    raw_profiles.append(raw_profile)
+
+  if len(raw_profiles) == 0:
+    print("No raw profiles could be generated.")
+    return -1
+
+  binaries_flag = []
+  for binary in binaries:
+    binaries_flag.append('-object')
+    binaries_flag.append(binary)
+
+  llvm_bin_dir = GetLLVMBinDirectory()
+
+  # Merge all raw profiles into a single profile.
+  profdata_binary = os.path.join(llvm_bin_dir, "llvm-profdata")
+
+  print("Merging %d raw profile(s) into single profile." % len(raw_profiles))
+  merged_profile_path = os.path.join(output, "all.profile")
+  RemoveIfExists(merged_profile_path)
+  merge_command = [profdata_binary, "merge", "-sparse"] + raw_profiles + ["-o", merged_profile_path]
+  subprocess.check_call(merge_command)
+  print("Done.")
+
+  if not os.path.exists(merged_profile_path):
+    print("Could not generate or find merged profile %s." % merged_profile_path)
+    return -1
+
+  llvm_cov_binary = os.path.join(llvm_bin_dir, "llvm-cov")
+  instr_profile_flag = "-instr-profile=%s" % merged_profile_path
+  ignore_flags = "-ignore-filename-regex=third_party|unittest|fixture"
+
+  # Generate the HTML report if specified.
+  if generate_all_reports or args.format == 'html':
+    print("Generating HTML report.")
+    show_command = [llvm_cov_binary, "show"] + binaries_flag + [
+      instr_profile_flag,
+      "-format=html",
+      "-output-dir=%s" % output,
+      "-tab-size=2",
+      ignore_flags,
+    ]
+    subprocess.check_call(show_command)
+    print("Done.")
+
+  # Generate a report summary if specified.
+  if generate_all_reports or args.format == 'summary':
+    print("Generating a summary report.")
+    report_command = [llvm_cov_binary, "report"] + binaries_flag + [
+      instr_profile_flag,
+      ignore_flags,
+    ]
+    subprocess.check_call(report_command)
+    print("Done.")
+
+  return 0
+
+if __name__ == '__main__':
+  sys.exit(main())

engine/src/flutter/tools/gn

@@ -93,6 +93,8 @@ def to_gn_args(args):
 
     gn_args['embedder_for_target'] = args.embedder_for_target
 
+    gn_args['enable_coverage'] = args.coverage
+
     if args.operator_new_alignment is not None:
       gn_args['operator_new_alignment'] = args.operator_new_alignment
 
@@ -261,6 +263,8 @@ def parse_args(args):
 
   parser.add_argument('--embedder-for-target', dest='embedder_for_target', action='store_true', default=False)
 
+  parser.add_argument('--coverage', default=False, action='store_true')
+
   return parser.parse_args(args)
 
 def main(argv):