[llvm-cov] Allow branch coverage to be skipped when exporting for LCOV

This small patch adds a '--skip-branches' option to the llvm-cov export
options. This option allows branch coverage information to be skipped from the
exported LCOV directives if it's not needed. For now, this only works when
exporting LCOV (which is noted in the option description), but it can be
extended for JSON later if it makes sense.

Differential Revision: https://reviews.llvm.org/D135986

llvm/test/tools/llvm-cov/branch-export-lcov.test

@@ -1,6 +1,7 @@
 
 // RUN: llvm-profdata merge %S/Inputs/branch-showBranchPercentage.proftext -o %t.profdata
 // RUN: llvm-cov export --format=lcov %S/Inputs/branch-showBranchPercentage.o32l -instr-profile %t.profdata | FileCheck %s
+// RUN: llvm-cov export --format=lcov --skip-branches %S/Inputs/branch-showBranchPercentage.o32l -instr-profile %t.profdata | FileCheck %s --check-prefix=NOBRANCH
 
 // CHECK-DAG: BRDA:14,0,0,1
 // CHECK-DAG: BRDA:14,0,1,5
@@ -39,6 +40,7 @@
 // Check recursive macro-expansions.
 // RUN: llvm-profdata merge %S/Inputs/branch-macros.proftext -o %t.profdata
 // RUN: llvm-cov export --format=lcov %S/Inputs/branch-macros.o32l -instr-profile %t.profdata | FileCheck %s -check-prefix=MACROS
+// RUN: llvm-cov export --format=lcov --skip-branches %S/Inputs/branch-macros.o32l -instr-profile %t.profdata | FileCheck %s -check-prefix=NOBRANCH
 
 // MACROS-COUNT-4: BRDA:17
 // MACROS-NOT: BRDA:17
@@ -71,3 +73,8 @@
 // MACROS-NOT: BRDA
 // MACROS: BRF:40
 // MACROS: BRH:24
+
+// NOBRANCH-NOT: BRDA
+// NOBRANCH-NOT: BRF
+// NOBRANCH-NOT: BRH
+

llvm/tools/llvm-cov/CodeCoverage.cpp

@@ -1192,12 +1192,17 @@ int CodeCoverageTool::doExport(int argc, const char **argv,
                               cl::desc("Don't export per-function data"),
                               cl::cat(ExportCategory));
 
+  cl::opt<bool> SkipBranches("skip-branches", cl::Optional,
+                              cl::desc("Don't export branch data (LCOV)"),
+                              cl::cat(ExportCategory));
+
   auto Err = commandLineParser(argc, argv);
   if (Err)
     return Err;
 
   ViewOpts.SkipExpansions = SkipExpansions;
   ViewOpts.SkipFunctions = SkipFunctions;
+  ViewOpts.SkipBranches = SkipBranches;
 
   if (ViewOpts.Format != CoverageViewOptions::OutputFormat::Text &&
       ViewOpts.Format != CoverageViewOptions::OutputFormat::Lcov) {

llvm/tools/llvm-cov/CoverageExporterLcov.cpp

@@ -173,7 +173,7 @@ void renderBranchSummary(raw_ostream &OS, const FileCoverageSummary &Summary) {
 void renderFile(raw_ostream &OS, const coverage::CoverageMapping &Coverage,
                 const std::string &Filename,
                 const FileCoverageSummary &FileReport, bool ExportSummaryOnly,
-                bool SkipFunctions) {
+                bool SkipFunctions, bool SkipBranches) {
   OS << "SF:" << Filename << '\n';
 
   if (!ExportSummaryOnly && !SkipFunctions) {
@@ -185,9 +185,11 @@ void renderFile(raw_ostream &OS, const coverage::CoverageMapping &Coverage,
     // Calculate and render detailed coverage information for given file.
     auto FileCoverage = Coverage.getCoverageForFile(Filename);
     renderLineExecutionCounts(OS, FileCoverage);
-    renderBranchExecutionCounts(OS, Coverage, FileCoverage);
+    if (!SkipBranches)
+      renderBranchExecutionCounts(OS, Coverage, FileCoverage);
   }
-  renderBranchSummary(OS, FileReport);
+  if (!SkipBranches)
+    renderBranchSummary(OS, FileReport);
   renderLineSummary(OS, FileReport);
 
   OS << "end_of_record\n";
@@ -196,10 +198,11 @@ void renderFile(raw_ostream &OS, const coverage::CoverageMapping &Coverage,
 void renderFiles(raw_ostream &OS, const coverage::CoverageMapping &Coverage,
                  ArrayRef<std::string> SourceFiles,
                  ArrayRef<FileCoverageSummary> FileReports,
-                 bool ExportSummaryOnly, bool SkipFunctions) {
+                 bool ExportSummaryOnly, bool SkipFunctions,
+                 bool SkipBranches) {
   for (unsigned I = 0, E = SourceFiles.size(); I < E; ++I)
     renderFile(OS, Coverage, SourceFiles[I], FileReports[I], ExportSummaryOnly,
-               SkipFunctions);
+               SkipFunctions, SkipBranches);
 }
 
 } // end anonymous namespace
@@ -218,5 +221,5 @@ void CoverageExporterLcov::renderRoot(ArrayRef<std::string> SourceFiles) {
   auto FileReports = CoverageReport::prepareFileReports(Coverage, Totals,
                                                         SourceFiles, Options);
   renderFiles(OS, Coverage, SourceFiles, FileReports, Options.ExportSummaryOnly,
-              Options.SkipFunctions);
+              Options.SkipFunctions, Options.SkipBranches);
 }

llvm/tools/llvm-cov/CoverageViewOptions.h

@@ -41,6 +41,7 @@ struct CoverageViewOptions {
   bool ExportSummaryOnly;
   bool SkipExpansions;
   bool SkipFunctions;
+  bool SkipBranches;
   OutputFormat Format;
   BranchOutputType ShowBranches;
   std::string ShowOutputDirectory;