llvm-cov: Generalize -filename-equivalence

The filename-equivalence flag allows you to show coverage when your
source files don't have the same full paths as those that generated
the data. This is mostly useful for writing tests in a cross-platform
way.

This wasn't triggering in cases where the filename was derived
directly from the coverage data, which meant certain types of test
case were impossible to write. This patch fixes that, and following
patches involve tests that need this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218108 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-cov/CodeCoverage.cpp

@@ -87,9 +87,6 @@ public:
   /// \brief Return a memory buffer for the given source file.
   ErrorOr<const MemoryBuffer &> getSourceFile(StringRef SourceFile);
 
-  /// \brief Return true if two filepaths refer to the same file.
-  bool equivalentFiles(StringRef A, StringRef B);
-
   /// \brief Collect a set of function's file ids which correspond to the
   /// given source file. Return false if the set is empty.
   bool gatherInterestingFileIDs(StringRef SourceFile,
@@ -148,9 +145,22 @@ public:
       LoadedSourceFiles;
   std::vector<FunctionCoverageMapping> FunctionMappingRecords;
   bool CompareFilenamesOnly;
+  StringMap<std::string> RemappedFilenames;
 };
 }
 
+static std::vector<StringRef>
+getUniqueFilenames(ArrayRef<FunctionCoverageMapping> FunctionMappingRecords) {
+  std::vector<StringRef> Filenames;
+  for (const auto &Function : FunctionMappingRecords)
+    for (const auto &Filename : Function.Filenames)
+      Filenames.push_back(Filename);
+  std::sort(Filenames.begin(), Filenames.end());
+  auto Last = std::unique(Filenames.begin(), Filenames.end());
+  Filenames.erase(Last, Filenames.end());
+  return Filenames;
+}
+
 void CodeCoverageTool::error(const Twine &Message, StringRef Whence) {
   errs() << "error: ";
   if (!Whence.empty())
@@ -160,35 +170,31 @@ void CodeCoverageTool::error(const Twine &Message, StringRef Whence) {
 
 ErrorOr<const MemoryBuffer &>
 CodeCoverageTool::getSourceFile(StringRef SourceFile) {
-  SmallString<256> Path(SourceFile);
-  sys::fs::make_absolute(Path);
-  for (const auto &Files : LoadedSourceFiles) {
-    if (equivalentFiles(Path.str(), Files.first)) {
-      return *Files.second;
-    }
+  // If we've remapped filenames, look up the real location for this file.
+  if (!RemappedFilenames.empty()) {
+    auto Loc = RemappedFilenames.find(SourceFile);
+    if (Loc != RemappedFilenames.end())
+      SourceFile = Loc->second;
   }
+  for (const auto &Files : LoadedSourceFiles)
+    if (sys::fs::equivalent(SourceFile, Files.first))
+      return *Files.second;
   auto Buffer = MemoryBuffer::getFile(SourceFile);
   if (auto EC = Buffer.getError()) {
     error(EC.message(), SourceFile);
     return EC;
   }
-  LoadedSourceFiles.push_back(std::make_pair(
-      std::string(Path.begin(), Path.end()), std::move(Buffer.get())));
+  LoadedSourceFiles.push_back(
+      std::make_pair(SourceFile, std::move(Buffer.get())));
   return *LoadedSourceFiles.back().second;
 }
 
-bool CodeCoverageTool::equivalentFiles(StringRef A, StringRef B) {
-  if (CompareFilenamesOnly)
-    return sys::path::filename(A).equals_lower(sys::path::filename(B));
-  return sys::fs::equivalent(A, B);
-}
-
 bool CodeCoverageTool::gatherInterestingFileIDs(
     StringRef SourceFile, const FunctionCoverageMapping &Function,
     SmallSet<unsigned, 8> &InterestingFileIDs) {
   bool Interesting = false;
   for (unsigned I = 0, E = Function.Filenames.size(); I < E; ++I) {
-    if (equivalentFiles(SourceFile, Function.Filenames[I])) {
+    if (SourceFile == Function.Filenames[I]) {
       InterestingFileIDs.insert(I);
       Interesting = true;
     }
@@ -204,7 +210,7 @@ CodeCoverageTool::findMainViewFileID(StringRef SourceFile,
   llvm::SmallVector<bool, 8> FilenameEquivalence(Function.Filenames.size(),
                                                  false);
   for (unsigned I = 0, E = Function.Filenames.size(); I < E; ++I) {
-    if (equivalentFiles(SourceFile, Function.Filenames[I]))
+    if (SourceFile == Function.Filenames[I])
       FilenameEquivalence[I] = true;
   }
   for (const auto &CR : Function.CountedRegions) {
@@ -394,6 +400,20 @@ bool CodeCoverageTool::load() {
 
     FunctionMappingRecords.push_back(Function);
   }
+
+  if (CompareFilenamesOnly) {
+    auto CoveredFiles = getUniqueFilenames(FunctionMappingRecords);
+    for (auto &SF : SourceFiles) {
+      StringRef SFBase = sys::path::filename(SF);
+      for (const auto &CF : CoveredFiles)
+        if (SFBase == sys::path::filename(CF)) {
+          RemappedFilenames[CF] = SF;
+          SF = CF;
+          break;
+        }
+    }
+  }
+
   return false;
 }
 
@@ -416,7 +436,8 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
 
   cl::opt<bool> FilenameEquivalence(
       "filename-equivalence", cl::Optional,
-      cl::desc("Compare the filenames instead of full filepaths"));
+      cl::desc("Treat source files as equivalent to paths in the coverage data "
+               "when the file names match, even if the full paths do not"));
 
   cl::OptionCategory FilteringCategory("Function filtering options");
 
@@ -495,7 +516,14 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
       Filters.push_back(std::unique_ptr<CoverageFilter>(StatFilterer));
     }
 
-    SourceFiles = InputSourceFiles;
+    for (const auto &File : InputSourceFiles) {
+      SmallString<128> Path(File);
+      if (std::error_code EC = sys::fs::make_absolute(Path)) {
+        errs() << "error: " << File << ": " << EC.message();
+        return 1;
+      }
+      SourceFiles.push_back(Path.str());
+    }
     return 0;
   };
 
@@ -599,16 +627,10 @@ int CodeCoverageTool::show(int argc, const char **argv,
   // Show files
   bool ShowFilenames = SourceFiles.size() != 1;
 
-  if (SourceFiles.empty()) {
+  if (SourceFiles.empty())
     // Get the source files from the function coverage mapping
-    std::set<StringRef> UniqueFilenames;
-    for (const auto &Function : FunctionMappingRecords) {
-      for (const auto &Filename : Function.Filenames)
-        UniqueFilenames.insert(Filename);
-    }
-    for (const auto &Filename : UniqueFilenames)
+    for (StringRef Filename : getUniqueFilenames(FunctionMappingRecords))
       SourceFiles.push_back(Filename);
-  }
 
   for (const auto &SourceFile : SourceFiles) {
     auto SourceBuffer = getSourceFile(SourceFile);