llvm-cov: add code coverage tool that's based on coverage mapping format and clang's pgo.

This commit expands llvm-cov's functionality by adding support for a new code coverage
tool that uses LLVM's coverage mapping format and clang's instrumentation based profiling.
The gcov compatible tool can be invoked by supplying the 'gcov' command as the first argument,
or by modifying the tool's name to end with 'gcov'.

Differential Revision: http://reviews.llvm.org/D4445

llvm-svn: 216300

1 files changed, 95 insertions, 0 deletions

diff --git a/llvm/tools/llvm-cov/CoverageSummaryInfo.cpp b/llvm/tools/llvm-cov/CoverageSummaryInfo.cpp
new file mode 100644
index 00000000000..765bb3ef84f
--- /dev/null
+++ b/llvm/tools/llvm-cov/CoverageSummaryInfo.cpp
@@ -0,0 +1,95 @@
+//===- CoverageSummaryInfo.cpp - Coverage summary for function/file -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// These structures are used to represent code coverage metrics
+// for functions/files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CoverageSummaryInfo.h"
+
+using namespace llvm;
+using namespace coverage;
+
+FunctionCoverageSummary
+FunctionCoverageSummary::get(const FunctionCoverageMapping &Function) {
+  // Compute the region coverage
+  size_t NumCodeRegions = 0, CoveredRegions = 0;
+  for (auto &Region : Function.MappingRegions) {
+    if (Region.Kind != CounterMappingRegion::CodeRegion)
+      continue;
+    ++NumCodeRegions;
+    if (Region.ExecutionCount != 0)
+      ++CoveredRegions;
+  }
+
+  // Compute the line coverage
+  size_t NumLines = 0, CoveredLines = 0;
+  for (unsigned FileID = 0, E = Function.Filenames.size(); FileID < E;
+       ++FileID) {
+    // Find the line start and end of the function's source code
+    // in that particular file
+    unsigned LineStart = std::numeric_limits<unsigned>::max();
+    unsigned LineEnd = 0;
+    for (auto &Region : Function.MappingRegions) {
+      if (Region.FileID != FileID)
+        continue;
+      LineStart = std::min(LineStart, Region.LineStart);
+      LineEnd = std::max(LineEnd, Region.LineEnd);
+    }
+    unsigned LineCount = LineEnd - LineStart + 1;
+
+    // Get counters
+    llvm::SmallVector<uint64_t, 16> ExecutionCounts;
+    ExecutionCounts.resize(LineCount, 0);
+    for (auto &Region : Function.MappingRegions) {
+      if (Region.FileID != FileID)
+        continue;
+      // Ignore the lines that were skipped by the preprocessor.
+      auto ExecutionCount = Region.ExecutionCount;
+      if (Region.Kind == MappingRegion::SkippedRegion) {
+        LineCount -= Region.LineEnd - Region.LineStart + 1;
+        ExecutionCount = 1;
+      }
+      for (unsigned I = Region.LineStart; I <= Region.LineEnd; ++I)
+        ExecutionCounts[I - LineStart] = ExecutionCount;
+    }
+    CoveredLines += LineCount - std::count(ExecutionCounts.begin(),
+                                           ExecutionCounts.end(), 0);
+    NumLines += LineCount;
+  }
+  return FunctionCoverageSummary(
+      Function.PrettyName, RegionCoverageInfo(CoveredRegions, NumCodeRegions),
+      LineCoverageInfo(CoveredLines, 0, NumLines));
+}
+
+FileCoverageSummary
+FileCoverageSummary::get(StringRef Name,
+                         ArrayRef<FunctionCoverageSummary> FunctionSummaries) {
+  size_t NumRegions = 0, CoveredRegions = 0;
+  size_t NumLines = 0, NonCodeLines = 0, CoveredLines = 0;
+  size_t NumFunctionsCovered = 0;
+  for (const auto &Func : FunctionSummaries) {
+    CoveredRegions += Func.RegionCoverage.Covered;
+    NumRegions += Func.RegionCoverage.NumRegions;
+
+    CoveredLines += Func.LineCoverage.Covered;
+    NonCodeLines += Func.LineCoverage.NonCodeLines;
+    NumLines += Func.LineCoverage.NumLines;
+
+    if (Func.RegionCoverage.isFullyCovered())
+      ++NumFunctionsCovered;
+  }
+
+  return FileCoverageSummary(
+      Name, RegionCoverageInfo(CoveredRegions, NumRegions),
+      LineCoverageInfo(CoveredLines, NonCodeLines, NumLines),
+      FunctionCoverageInfo(NumFunctionsCovered, FunctionSummaries.size()),
+      FunctionSummaries);
+}