[Coverage] Add an API to retrive all instantiations of a function (NFC)

The CoverageMapping::getInstantiations() API retrieved all function
records corresponding to functions with more than one instantiation (e.g
template functions with multiple specializations). However, there was no
simple way to determine *which* function a given record was an
instantiation of. This was an oversight, since it's useful to aggregate
coverage information over all instantiations of a function.

llvm-cov works around this by building a mapping of source locations to
instantiation sets, but this duplicates logic that libCoverage already
has (see FunctionInstantiationSetCollector).

This change adds a new API, CoverageMapping::getInstantiationGroups(),
which returns a list of InstantiationGroups. A group contains records
for each instantiation of some particular function, and also provides
utilities to get the total execution count within the group, the source
location of the common definition, etc.

This lets removes some hacky logic in llvm-cov by reusing
FunctionInstantiationSetCollector and makes the CoverageMapping API
friendlier for other clients.

llvm-svn: 309904

1 files changed, 12 insertions, 18 deletions

diff --git a/llvm/tools/llvm-cov/CoverageReport.cpp b/llvm/tools/llvm-cov/CoverageReport.cpp
index c68bb9048df..7c273a2430c 100644
--- a/llvm/tools/llvm-cov/CoverageReport.cpp
+++ b/llvm/tools/llvm-cov/CoverageReport.cpp
@@ -317,25 +317,19 @@ CoverageReport::prepareFileReports(const coverage::CoverageMapping &Coverage,
   for (StringRef Filename : Files) {
     FileCoverageSummary Summary(Filename.drop_front(LCP));
 
-    // Map source locations to aggregate function coverage summaries.
-    DenseMap<std::pair<unsigned, unsigned>, FunctionCoverageSummary> Summaries;
-
-    for (const auto &F : Coverage.getCoveredFunctions(Filename)) {
-      FunctionCoverageSummary Function = FunctionCoverageSummary::get(F);
-      auto StartLoc = F.CountedRegions[0].startLoc();
-
-      auto UniquedSummary = Summaries.insert({StartLoc, Function});
-      if (!UniquedSummary.second)
-        UniquedSummary.first->second.update(Function);
-
-      Summary.addInstantiation(Function);
-      Totals.addInstantiation(Function);
-    }
+    for (const auto &Group : Coverage.getInstantiationGroups(Filename)) {
+      std::vector<FunctionCoverageSummary> InstantiationSummaries;
+      for (const coverage::FunctionRecord *F : Group.getInstantiations()) {
+        auto InstantiationSummary = FunctionCoverageSummary::get(*F);
+        Summary.addInstantiation(InstantiationSummary);
+        Totals.addInstantiation(InstantiationSummary);
+        InstantiationSummaries.push_back(InstantiationSummary);
+      }
 
-    for (const auto &UniquedSummary : Summaries) {
-      const FunctionCoverageSummary &FCS = UniquedSummary.second;
-      Summary.addFunction(FCS);
-      Totals.addFunction(FCS);
+      auto GroupSummary =
+          FunctionCoverageSummary::get(Group, InstantiationSummaries);
+      Summary.addFunction(GroupSummary);
+      Totals.addFunction(GroupSummary);
     }
 
     FileReports.push_back(Summary);