[llvm-cov] Add lcov tracefile export format.

Summary:
lcov tracefiles are used by various coverage reporting tools and build
systems (e.g., Bazel). It is a simple text-based format to parse and
more convenient to use than the JSON export format, which needs
additional processing to map regions/segments back to line numbers.

It's a little unfortunate that "text" format is now overloaded to refer
specifically to JSON for export, but I wanted to avoid making any
breaking changes to the UI of the llvm-cov tool at this time.

Patch by Tony Allevato (@allevato).

Reviewers: Dor1s, vsk

Reviewed By: Dor1s, vsk

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D54266

llvm-svn: 346506

1 files changed, 125 insertions, 0 deletions

diff --git a/llvm/tools/llvm-cov/CoverageExporterLcov.cpp b/llvm/tools/llvm-cov/CoverageExporterLcov.cpp
new file mode 100644
index 00000000000..d149ba1a4c8
--- /dev/null
+++ b/llvm/tools/llvm-cov/CoverageExporterLcov.cpp
@@ -0,0 +1,125 @@
+//===- CoverageExporterLcov.cpp - Code coverage export --------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements export of code coverage data to lcov trace file format.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+//
+// The trace file code coverage export follows the following format (see also
+// https://linux.die.net/man/1/geninfo). Each quoted string appears on its own
+// line; the indentation shown here is only for documentation purposes.
+//
+// - for each source file:
+//   - "SF:<absolute path to source file>"
+//   - for each function:
+//     - "FN:<line number of function start>,<function name>"
+//   - for each function:
+//     - "FNDA:<execution count>,<function name>"
+//   - "FNF:<number of functions found>"
+//   - "FNH:<number of functions hit>"
+//   - for each instrumented line:
+//     - "DA:<line number>,<execution count>[,<checksum>]
+//   - "LH:<number of lines with non-zero execution count>"
+//   - "LF:<nubmer of instrumented lines>"
+//   - "end_of_record"
+//
+// If the user is exporting summary information only, then the FN, FNDA, and DA
+// lines will not be present.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CoverageExporterLcov.h"
+#include "CoverageReport.h"
+
+using namespace llvm;
+
+namespace {
+
+void renderFunctionSummary(raw_ostream &OS,
+                           const FileCoverageSummary &Summary) {
+  OS << "FNF:" << Summary.FunctionCoverage.getNumFunctions() << '\n'
+     << "FNH:" << Summary.FunctionCoverage.getExecuted() << '\n';
+}
+
+void renderFunctions(
+    raw_ostream &OS,
+    const iterator_range<coverage::FunctionRecordIterator> &Functions) {
+  for (const auto &F : Functions) {
+    auto StartLine = F.CountedRegions.front().LineStart;
+    OS << "FN:" << StartLine << ',' << F.Name << '\n';
+  }
+  for (const auto &F : Functions)
+    OS << "FNDA:" << F.ExecutionCount << ',' << F.Name << '\n';
+}
+
+void renderLineExecutionCounts(raw_ostream &OS,
+                               const coverage::CoverageData &FileCoverage) {
+  coverage::LineCoverageIterator LCI{FileCoverage, 1};
+  coverage::LineCoverageIterator LCIEnd = LCI.getEnd();
+  for (; LCI != LCIEnd; ++LCI) {
+    const coverage::LineCoverageStats &LCS = *LCI;
+    if (LCS.isMapped()) {
+      OS << "DA:" << LCS.getLine() << ',' << LCS.getExecutionCount() << '\n';
+    }
+  }
+}
+
+void renderLineSummary(raw_ostream &OS, const FileCoverageSummary &Summary) {
+  OS << "LF:" << Summary.LineCoverage.getNumLines() << '\n'
+     << "LH:" << Summary.LineCoverage.getCovered() << '\n';
+}
+
+void renderFile(raw_ostream &OS, const coverage::CoverageMapping &Coverage,
+                const std::string &Filename,
+                const FileCoverageSummary &FileReport, bool ExportSummaryOnly) {
+  OS << "SF:" << Filename << '\n';
+
+  if (!ExportSummaryOnly) {
+    renderFunctions(OS, Coverage.getCoveredFunctions());
+  }
+  renderFunctionSummary(OS, FileReport);
+
+  if (!ExportSummaryOnly) {
+    // Calculate and render detailed coverage information for given file.
+    auto FileCoverage = Coverage.getCoverageForFile(Filename);
+    renderLineExecutionCounts(OS, FileCoverage);
+  }
+  renderLineSummary(OS, FileReport);
+
+  OS << "end_of_record\n";
+}
+
+void renderFiles(raw_ostream &OS, const coverage::CoverageMapping &Coverage,
+                 ArrayRef<std::string> SourceFiles,
+                 ArrayRef<FileCoverageSummary> FileReports,
+                 bool ExportSummaryOnly) {
+  for (unsigned I = 0, E = SourceFiles.size(); I < E; ++I)
+    renderFile(OS, Coverage, SourceFiles[I], FileReports[I], ExportSummaryOnly);
+}
+
+} // end anonymous namespace
+
+void CoverageExporterLcov::renderRoot(const CoverageFilters &IgnoreFilters) {
+  std::vector<std::string> SourceFiles;
+  for (StringRef SF : Coverage.getUniqueSourceFiles()) {
+    if (!IgnoreFilters.matchesFilename(SF))
+      SourceFiles.emplace_back(SF);
+  }
+  renderRoot(SourceFiles);
+}
+
+void CoverageExporterLcov::renderRoot(ArrayRef<std::string> SourceFiles) {
+  FileCoverageSummary Totals = FileCoverageSummary("Totals");
+  auto FileReports = CoverageReport::prepareFileReports(Coverage, Totals,
+                                                        SourceFiles, Options);
+  renderFiles(OS, Coverage, SourceFiles, FileReports,
+              Options.ExportSummaryOnly);
+}