[Coverage] Add support for Branch Coverage in LLVM Source-Based Code Coverage

This is an enhancement to LLVM Source-Based Code Coverage in clang to track how
many times individual branch-generating conditions are taken (evaluate to TRUE)
and not taken (evaluate to FALSE).  Individual conditions may comprise larger
boolean expressions using boolean logical operators.  This functionality is
very similar to what is supported by GCOV except that it is very closely
anchored to the ASTs.

Differential Revision: https://reviews.llvm.org/D84467

1 files changed, 18 insertions, 1 deletions

diff --git a/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp b/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
index 87dab21..4c90eaa 100644
--- a/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
+++ b/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
@@ -249,7 +249,12 @@ Error CoverageMapping::loadFunctionRecord(
       consumeError(std::move(E));
       return Error::success();
     }
-    Function.pushRegion(Region, *ExecutionCount);
+    Expected<int64_t> AltExecutionCount = Ctx.evaluate(Region.FalseCount);
+    if (auto E = AltExecutionCount.takeError()) {
+      consumeError(std::move(E));
+      return Error::success();
+    }
+    Function.pushRegion(Region, *ExecutionCount, *AltExecutionCount);
   }
 
   // Don't create records for (filenames, function) pairs we've already seen.
@@ -672,6 +677,10 @@ CoverageData CoverageMapping::getCoverageForFile(StringRef Filename) const {
         if (MainFileID && isExpansion(CR, *MainFileID))
           FileCoverage.Expansions.emplace_back(CR, Function);
       }
+    // Capture branch regions specific to the function (excluding expansions).
+    for (const auto &CR : Function.CountedBranchRegions)
+      if (FileIDs.test(CR.FileID) && (CR.FileID == CR.ExpandedFileID))
+        FileCoverage.BranchRegions.push_back(CR);
   }
 
   LLVM_DEBUG(dbgs() << "Emitting segments for file: " << Filename << "\n");
@@ -719,6 +728,10 @@ CoverageMapping::getCoverageForFunction(const FunctionRecord &Function) const {
       if (isExpansion(CR, *MainFileID))
         FunctionCoverage.Expansions.emplace_back(CR, Function);
     }
+  // Capture branch regions specific to the function (excluding expansions).
+  for (const auto &CR : Function.CountedBranchRegions)
+    if (CR.FileID == *MainFileID)
+      FunctionCoverage.BranchRegions.push_back(CR);
 
   LLVM_DEBUG(dbgs() << "Emitting segments for function: " << Function.Name
                     << "\n");
@@ -738,6 +751,10 @@ CoverageData CoverageMapping::getCoverageForExpansion(
       if (isExpansion(CR, Expansion.FileID))
         ExpansionCoverage.Expansions.emplace_back(CR, Expansion.Function);
     }
+  for (const auto &CR : Expansion.Function.CountedBranchRegions)
+    // Capture branch regions that only pertain to the corresponding expansion.
+    if (CR.FileID == Expansion.FileID)
+      ExpansionCoverage.BranchRegions.push_back(CR);
 
   LLVM_DEBUG(dbgs() << "Emitting segments for expansion of file "
                     << Expansion.FileID << "\n");