Adds a flag to generate LLVM coverage symbols.

This change adds a new --experimental_use_llvm_covmap flag which may
be used in conjunction with the --collect_code_coverage flag to
generate LLVM style coverage symbols instead of gcov.

--
MOS_MIGRATED_REVID=131065609

3 files changed, 60 insertions, 12 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
index d516d17dfa..ec53d74de3 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
@@ -649,6 +649,14 @@ public final class BuildConfiguration {
             + "'//tools/test:coverage_report_generator'.")
     public Label coverageReportGenerator;
 
+    @Option(name = "experimental_use_llvm_covmap",
+        defaultValue = "false",
+        category = "experimental",
+        help = "If specified, Bazel will generate llvm-cov coverage map information rather than "
+            + "gcov when collect_code_coverage is enabled."
+    )
+    public boolean useLLVMCoverageMapFormat;
+
     @Option(name = "cache_test_results",
         defaultValue = "auto",
         category = "testing",
@@ -2237,6 +2245,10 @@ public final class BuildConfiguration {
     return options.collectMicroCoverage;
   }
 
+  public boolean isLLVMCoverageMapFormatEnabled() {
+    return options.useLLVMCoverageMapFormat;
+  }
+
   public boolean isActionsEnabled() {
     return actionsEnabled;
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index 70af928677..e9a89c782c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -333,6 +333,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   private final boolean stripBinaries;
   private final String solibDirectory;
   private final CompilationMode compilationMode;
+  private final boolean useLLVMCoverageMap;
 
   /**
    *  If true, the ConfiguredTarget is only used to get the necessary cross-referenced
@@ -353,6 +354,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     this.crosstoolTop = params.crosstoolTop;
     this.ccToolchainLabel = params.ccToolchainLabel;
     this.compilationMode = params.commonOptions.compilationMode;
+    this.useLLVMCoverageMap = params.commonOptions.useLLVMCoverageMapFormat;
     this.lipoContextCollector = cppOptions.lipoCollector;
 
 
@@ -947,6 +949,30 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
             toolchainBuilder);
       }
       if (!features.contains("coverage")) {
+        String compileFlags;
+        String linkerFlags;
+        if (useLLVMCoverageMap) {
+          compileFlags =
+              "flag_group {"
+              + " flag: '-fprofile-instr-generate'"
+              + " flag: '-fcoverage-mapping'"
+              + "}";
+          linkerFlags =
+              "  flag_group {"
+              + "  flag: '-fprofile-instr-generate'"
+              + "}";
+        } else {
+          compileFlags =
+              "  expand_if_all_available: 'gcov_gcno_file'"
+              + "flag_group {"
+              + "  flag: '-fprofile-arcs'"
+              + "  flag: '-ftest-coverage'"
+              + "}";
+          linkerFlags =
+              "  flag_group {"
+              + "  flag: '-lgcov'"
+              + "}";
+        }
         TextFormat.merge(
             ""
                 + "feature {"
@@ -959,19 +985,13 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
                 + "    action: 'c++-header-parsing'"
                 + "    action: 'c++-header-preprocessing'"
                 + "    action: 'c++-module-compile'"
-                + "    expand_if_all_available: 'gcov_gcno_file'"
-                + "    flag_group {"
-                + "      flag: '-fprofile-arcs'"
-                + "      flag: '-ftest-coverage'"
-                + "    }"
+                + compileFlags
                 + "  }"
                 + "  flag_set {"
                 + "    action: 'c++-link-interface-dynamic-library'"
                 + "    action: 'c++-link-dynamic-library'"
                 + "    action: 'c++-link-executable'"
-                + "    flag_group {"
-                + "      flag: '-lgcov'"
-                + "    }"
+                + linkerFlags
                 + "  }"
                 + "}",
             toolchainBuilder);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
index 4da2ff3eab..ba5adf1c5b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
@@ -123,11 +123,19 @@ public final class CompilationSupport {
   static final ImmutableList<String> LINKER_COVERAGE_FLAGS =
       ImmutableList.of("-ftest-coverage", "-fprofile-arcs");
 
+  @VisibleForTesting
+  static final ImmutableList<String> LINKER_LLVM_COVERAGE_FLAGS =
+      ImmutableList.of("-fprofile-instr-generate");
+
   // Flags for clang 6.1(xcode 6.4)
   @VisibleForTesting
-  static final ImmutableList<String> CLANG_COVERAGE_FLAGS =
+  static final ImmutableList<String> CLANG_GCOV_COVERAGE_FLAGS =
       ImmutableList.of("-fprofile-arcs", "-ftest-coverage");
 
+  @VisibleForTesting
+  static final ImmutableList<String> CLANG_LLVM_COVERAGE_FLAGS =
+      ImmutableList.of("-fprofile-instr-generate", "-fcoverage-mapping");
+
   // These are added by Xcode when building, because the simulator is built on OSX
   // frameworks so we aim compile to match the OSX objc runtime.
   @VisibleForTesting
@@ -548,7 +556,11 @@ public final class CompilationSupport {
 
     List<String> coverageFlags = ImmutableList.of();
     if (collectCodeCoverage) {
-      coverageFlags = CLANG_COVERAGE_FLAGS;
+      if (buildConfiguration.isLLVMCoverageMapFormatEnabled()) {
+        coverageFlags = CLANG_LLVM_COVERAGE_FLAGS;
+      } else {
+        coverageFlags = CLANG_GCOV_COVERAGE_FLAGS;
+      }
     }
 
     commandLine
@@ -658,7 +670,7 @@ public final class CompilationSupport {
         hasSwiftSources);
 
     Optional<Artifact> gcnoFile = Optional.absent();
-    if (runCodeCoverage) {
+    if (runCodeCoverage && !buildConfiguration.isLLVMCoverageMapFormatEnabled()) {
       gcnoFile = Optional.of(intermediateArtifacts.gcnoFile(sourceFile));
     }
 
@@ -1388,7 +1400,11 @@ public final class CompilationSupport {
         .add(objcProvider.get(ObjcProvider.LINKOPT));
 
     if (buildConfiguration.isCodeCoverageEnabled()) {
-      commandLine.add(LINKER_COVERAGE_FLAGS);
+      if (buildConfiguration.isLLVMCoverageMapFormatEnabled()) {
+        commandLine.add(LINKER_LLVM_COVERAGE_FLAGS);
+      } else {
+        commandLine.add(LINKER_COVERAGE_FLAGS);
+      }
     }
 
     if (objcProvider.is(USES_SWIFT)) {