Add tools for code coverage support in iOS.

In this CL, support is added to all unit tests targets and the Showcase
Earl Grey tests.

BUG=676034
R=sdefresne@chromium.org,marq@chromium.org,lindsayw@chromium.org

Review-Url: https://codereview.chromium.org/2789433004
Cr-Commit-Position: refs/heads/master@{#469301}

base/test/test_support_ios.mm

@@ -152,6 +152,8 @@ static char** g_argv;
 }
 
 - (void)runTests {
+  coverage_util::ConfigureCoverageReportPath();
+
   int exitStatus = g_test_suite->Run();
 
   if ([self shouldRedirectOutputToFile])
@@ -169,8 +171,6 @@ static char** g_argv;
   UIApplication* application = [UIApplication sharedApplication];
   [application _terminateWithStatus:exitStatus];
 
-  coverage_util::FlushCoverageDataIfNecessary();
-
   exit(exitStatus);
 }
 

build/config/ios/BUILD.gn

@@ -112,6 +112,10 @@ config("runtime_library") {
     cflags_cc = common_cc_flags
     cflags_objcc = common_cc_flags
   }
+
+  if (ios_enable_coverage) {
+    configs = [ ":enable_coverage" ]
+  }
 }
 
 config("ios_executable_flags") {
@@ -136,6 +140,16 @@ config("xctest_config") {
   ]
 }
 
+# This enables support for LLVM code coverage. See
+# http://llvm.org/docs/CoverageMappingFormat.html.
+config("enable_coverage") {
+  cflags = [
+    "-fprofile-instr-generate",
+    "-fcoverage-mapping",
+  ]
+  ldflags = [ "-fprofile-instr-generate" ]
+}
+
 group("xctest") {
   public_configs = [ ":xctest_config" ]
 }

build/config/ios/ios_sdk.gni

@@ -37,6 +37,10 @@ declare_args() {
   # to avoid running out of certificates if using a free account.
   ios_automatically_manage_certs = true
 
+  # Enabling this option makes clang compile for profiling to gather code
+  # coverage metrics.
+  ios_enable_coverage = false
+
   # If non-empty, this list must contain valid cpu architecture, and the final
   # build will be a multi-architecture build (aka fat build) supporting the
   # main $target_cpu architecture and all of $additional_target_cpus.

build/secondary/testing/gtest/BUILD.gn

@@ -3,6 +3,10 @@
 # found in the LICENSE file.
 
 import("//build_overrides/gtest.gni")
+if (is_ios) {
+  import("//build/config/ios/ios_sdk.gni")
+  import("//build/buildflag_header.gni")
+}
 
 config("gtest_config") {
   visibility = [
@@ -72,6 +76,7 @@ static_library("gtest") {
     "src/gtest-typed-test.cc",
     "src/gtest.cc",
   ]
+  deps = []
 
   if (gtest_include_multiprocess) {
     sources += [
@@ -100,9 +105,10 @@ static_library("gtest") {
 
   if (is_ios && gtest_include_ios_coverage) {
     sources += [
-      "../coverage_util_ios.cc",
       "../coverage_util_ios.h",
+      "../coverage_util_ios.mm",
     ]
+    deps += [ ":ios_enable_coverage" ]
   }
 
   include_dirs = [ "." ]
@@ -128,3 +134,10 @@ source_set("gtest_main") {
     ":gtest",
   ]
 }
+
+if (is_ios) {
+  buildflag_header("ios_enable_coverage") {
+    header = "ios_enable_coverage.h"
+    flags = [ "IOS_ENABLE_COVERAGE=$ios_enable_coverage" ]
+  }
+}

docs/ios/coverage.md

+# Generate code coverage data
+
+1.  Build a test target for coverage:
+
+    ```
+    ninja -C out/Coverage-iphonesimulator ios_chrome_unittests
+    ```
+
+    Targets that support code coverage need to call
+    `coverage_util::ConfigureCoverageReportPath()`.
+    If you don't use `setup-gn.py`, you can set the gn argument
+    `ios_enable_coverage` to `true`.
+
+1.  Run the test target. If using Xcode, don't forget to set `Coverage` in the
+    target's scheme:
+
+    ![](images/coverage_xcode.png)
+
+1.  Find the `coverage.profraw` in the `Documents` folder of the app. You can
+    look in the console output of the instrumented target. For example:
+
+    ```
+    Coverage data at /Users/johndoe/Library/Developer/CoreSimulator/Devices/
+    82D642FA-FC18-4EDB-AFE0-A17454804BE4/data/Containers/Data/Application/
+    E6B2B898-CE13-4958-93F3-E8B500446381/Documents/coverage.profraw
+    ```
+
+1.  Create a `coverage.profdata` file out of the `coverage.profraw` file:
+
+    ```
+    xcrun llvm-profdata merge \
+        -o out/Coverage-iphonesimulator/coverage.profdata \
+        path/to/coverage.profraw
+    ```
+
+1.  To see the **line coverage** for *all the instrumented source files*:
+
+    ```
+    xcrun llvm-cov show \
+        out/Coverage-iphonesimulator/ios_chrome_unittests.app/ios_chrome_unittests \
+        -instr-profile=out/Coverage-iphonesimulator/coverage.profdata \
+        -arch=x86_64
+    ```
+
+    ![](images/llvm-cov_show.png)
+
+    To see the **line coverage** for a *specific instrumented source
+    file/folder* (e.g.
+    `ios/chrome/browser/ui/coordinators/browser_coordinator.mm`):
+
+    ```
+    xcrun llvm-cov show \
+        out/Coverage-iphonesimulator/ios_chrome_unittests.app/ios_chrome_unittests \
+        -instr-profile=out/Coverage-iphonesimulator/coverage.profdata \
+        -arch=x86_64 ios/chrome/browser/ui/coordinators/browser_coordinator.mm
+    ```
+
+    ![](images/llvm-cov_show_file.png)
+
+    To see a **complete report**:
+
+    ```
+    xcrun llvm-cov report \
+        out/Coverage-iphonesimulator/ios_chrome_unittests.app/ios_chrome_unittests \
+        -instr-profile=path/to/coverage.profdata -arch=x86_64
+    ```
+
+    ![](images/llvm-cov_report.png)
+
+    To see a **report** for a *folder/file* (e.g. `ios/chrome/browser` folder):
+
+    ```
+    xcrun llvm-cov show \
+        out/Coverage-iphonesimulator/ios_chrome_unittests.app/ios_chrome_unittests \
+        -instr-profile=path/to/coverage.profdata -arch=x86_64 ios/chrome/browser
+    ```
+
+    ![](images/llvm-cov_report_folder.png)

ios/build/tools/setup-gn.py

@@ -21,7 +21,7 @@ except ImportError:
 
 
 SUPPORTED_TARGETS = ('iphoneos', 'iphonesimulator')
-SUPPORTED_CONFIGS = ('Debug', 'Release', 'Profile', 'Official')
+SUPPORTED_CONFIGS = ('Debug', 'Release', 'Profile', 'Official', 'Coverage')
 
 
 class ConfigParserWithStringInterpolation(ConfigParser.SafeConfigParser):
@@ -90,12 +90,13 @@ class GnGenerator(object):
       if goma_dir:
         args.append(('goma_dir', '"%s"' % os.path.expanduser(goma_dir)))
 
-    args.append(('is_debug', self._config == 'Debug'))
+    args.append(('is_debug', self._config in ('Debug', 'Coverage')))
     args.append(('enable_dsyms', self._config in ('Profile', 'Official')))
     args.append(('enable_stripping', 'enable_dsyms'))
     args.append(('is_official_build', self._config == 'Official'))
     args.append(('is_chrome_branded', 'is_official_build'))
     args.append(('use_xcode_clang', 'is_official_build'))
+    args.append(('ios_enable_coverage', self._config == 'Coverage'))
     if os.environ.get('FORCE_MAC_TOOLCHAIN', '0') == '1':
       args.append(('use_system_xcode', False))
 

ios/showcase/test/BUILD.gn

@@ -14,6 +14,7 @@ source_set("test") {
     "//base",
     "//ios/testing/earl_grey:earl_grey_support",
     "//ios/third_party/earl_grey",
+    "//testing/gtest",
   ]
   public_deps = [
     "//build/config/ios:xctest",

ios/showcase/test/showcase_test_case.mm

@@ -7,6 +7,7 @@
 #import <EarlGrey/EarlGrey.h>
 
 #import "base/logging.h"
+#include "testing/coverage_util_ios.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -14,6 +15,10 @@
 
 @implementation ShowcaseTestCase
 
++ (void)setUp {
+  coverage_util::ConfigureCoverageReportPath();
+}
+
 // Overrides testInvocations so the set of tests run can be modified, as
 // necessary.
 + (NSArray*)testInvocations {

testing/coverage_util_ios.cc

-// Copyright 2014 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.
-
-extern "C" void __gcov_flush(void);
-
-namespace coverage_util {
-
-void FlushCoverageDataIfNecessary() {
-#if !defined(NDEBUG) && defined(ENABLE_TEST_CODE_COVERAGE)
-  __gcov_flush();
-#endif
-}
-
-}  // namespace coverage_util

testing/coverage_util_ios.h

@@ -7,10 +7,9 @@
 
 namespace coverage_util {
 
-// Flushes .gcda coverage files if ENABLE_TEST_CODE_COVERAGE is defined. iOS 7
-// does not call any code at the "end" of an app so flushing should be
-// performed manually.
-void FlushCoverageDataIfNecessary();
+// In debug builds, if IOS_ENABLE_COVERAGE is defined, sets the filename of the
+// coverage file. Otherwise, it does nothing.
+void ConfigureCoverageReportPath();
 
 }  // namespace coverage_util
 

testing/coverage_util_ios.mm

+// Copyright 2017 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 <Foundation/Foundation.h>
+
+#import "testing/gtest/ios_enable_coverage.h"
+
+#if !defined(NDEBUG) && BUILDFLAG(IOS_ENABLE_COVERAGE)
+extern "C" void __llvm_profile_set_filename(const char* name);
+#endif
+
+namespace coverage_util {
+
+void ConfigureCoverageReportPath() {
+#if !defined(NDEBUG) && BUILDFLAG(IOS_ENABLE_COVERAGE)
+  static dispatch_once_t once_token;
+  dispatch_once(&once_token, ^{
+    // Writes the profraw file to the Documents directory, where the app has
+    // write rights.
+    NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
+                                                         NSUserDomainMask, YES);
+    NSString* documents_directory = [paths firstObject];
+    NSString* file_name = [documents_directory
+        stringByAppendingPathComponent:@"coverage.profraw"];
+
+    // For documentation, see:
+    // http://clang.llvm.org/docs/SourceBasedCodeCoverage.html
+    __llvm_profile_set_filename(
+        [file_name cStringUsingEncoding:NSUTF8StringEncoding]);
+
+    // Print the path for easier retrieval.
+    NSLog(@"Coverage data at %@.", file_name);
+  });
+#endif  // !defined(NDEBUG) && BUILDFLAG(IOS_ENABLE_COVERAGE)
+}
+
+}  // namespace coverage_util