[Coverage] Prevent detection of false instantiations in case of macro expansion.

The root of the problem was that findMainViewFileID(File, Function)
could return some ID for any given file, even though that file
was not the main file for that function.

This patch ensures that the result of this function is conformed
with the result of findMainViewFileID(Function).

Differential Revision: http://reviews.llvm.org/D18787

llvm-svn: 266436

7 files changed, 102 insertions, 19 deletions

diff --git a/llvm/lib/ProfileData/CoverageMapping.cpp b/llvm/lib/ProfileData/CoverageMapping.cpp
index e130565500f..334de3c3b06 100644
--- a/llvm/lib/ProfileData/CoverageMapping.cpp
+++ b/llvm/lib/ProfileData/CoverageMapping.cpp
@@ -375,21 +375,7 @@ static SmallBitVector gatherFileIDs(StringRef SourceFile,
   return FilenameEquivalence;
 }
 
-static Optional<unsigned> findMainViewFileID(StringRef SourceFile,
-                                             const FunctionRecord &Function) {
-  SmallBitVector IsNotExpandedFile(Function.Filenames.size(), true);
-  SmallBitVector FilenameEquivalence = gatherFileIDs(SourceFile, Function);
-  for (const auto &CR : Function.CountedRegions)
-    if (CR.Kind == CounterMappingRegion::ExpansionRegion &&
-        FilenameEquivalence[CR.FileID])
-      IsNotExpandedFile[CR.ExpandedFileID] = false;
-  IsNotExpandedFile &= FilenameEquivalence;
-  int I = IsNotExpandedFile.find_first();
-  if (I == -1)
-    return None;
-  return I;
-}
-
+/// Return the ID of the file where the definition of the function is located.
 static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
   SmallBitVector IsNotExpandedFile(Function.Filenames.size(), true);
   for (const auto &CR : Function.CountedRegions)
@@ -401,6 +387,16 @@ static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
   return I;
 }
 
+/// Check if SourceFile is the file that contains the definition of
+/// the Function. Return the ID of the file in that case or None otherwise.
+static Optional<unsigned> findMainViewFileID(StringRef SourceFile,
+                                             const FunctionRecord &Function) {
+  Optional<unsigned> I = findMainViewFileID(Function);
+  if (I && SourceFile == Function.Filenames[*I])
+    return I;
+  return None;
+}
+
 /// Sort a nested sequence of regions from a single file.
 template <class It> static void sortNestedRegions(It First, It Last) {
   std::sort(First, Last,
@@ -422,13 +418,11 @@ CoverageData CoverageMapping::getCoverageForFile(StringRef Filename) {
 
   for (const auto &Function : Functions) {
     auto MainFileID = findMainViewFileID(Filename, Function);
-    if (!MainFileID)
-      continue;
     auto FileIDs = gatherFileIDs(Filename, Function);
     for (const auto &CR : Function.CountedRegions)
       if (FileIDs.test(CR.FileID)) {
         Regions.push_back(CR);
-        if (isExpansion(CR, *MainFileID))
+        if (MainFileID && isExpansion(CR, *MainFileID))
           FileCoverage.Expansions.emplace_back(CR, Function);
       }
   }
diff --git a/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.covmapping b/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.covmapping
new file mode 100644
index 00000000000..c255aa3272f
--- /dev/null
+++ b/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.covmapping
diff --git a/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.cpp b/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.cpp
new file mode 100644
index 00000000000..2a84f1dd58e
--- /dev/null
+++ b/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.cpp
@@ -0,0 +1,15 @@
+#include "prevent_false_instantiations.h"
+
+void func1() {
+  DO_SOMETHING();
+}
+
+void func2() {
+  DO_SOMETHING();
+}
+
+int main() {
+  func1();
+  func2();
+  return 0;
+}
diff --git a/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.proftext b/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.proftext
new file mode 100644
index 00000000000..ad5362e17e4
--- /dev/null
+++ b/llvm/test/tools/llvm-cov/Inputs/prevent_false_instantiations.proftext
@@ -0,0 +1,26 @@
+_Z5func1v
+# Func Hash:
+3
+# Num Counters:
+2
+# Counter Values:
+1
+0
+
+_Z5func2v
+# Func Hash:
+3
+# Num Counters:
+2
+# Counter Values:
+1
+0
+
+main
+# Func Hash:
+0
+# Num Counters:
+1
+# Counter Values:
+1
+
diff --git a/llvm/test/tools/llvm-cov/lit.local.cfg b/llvm/test/tools/llvm-cov/lit.local.cfg
index 05aef8645e4..8b6fe62772f 100644
--- a/llvm/test/tools/llvm-cov/lit.local.cfg
+++ b/llvm/test/tools/llvm-cov/lit.local.cfg
@@ -1 +1 @@
-config.suffixes = ['.test', '.m', '.cpp', '.c']
+config.suffixes = ['.test', '.m', '.cpp', '.c', '.h']
diff --git a/llvm/test/tools/llvm-cov/prevent_false_instantiations.h b/llvm/test/tools/llvm-cov/prevent_false_instantiations.h
new file mode 100644
index 00000000000..667ebde6d16
--- /dev/null
+++ b/llvm/test/tools/llvm-cov/prevent_false_instantiations.h
@@ -0,0 +1,10 @@
+// Checks that function instantiations don't go to a wrong file.
+
+// CHECK-NOT: {{_Z5func[1,2]v}}
+
+// RUN: llvm-profdata merge %S/Inputs/prevent_false_instantiations.proftext -o %t.profdata
+// RUN: llvm-cov show %S/Inputs/prevent_false_instantiations.covmapping -instr-profile %t.profdata -filename-equivalence %s | FileCheck %s
+
+#define DO_SOMETHING() \
+  do {                 \
+  } while (0)
diff --git a/llvm/unittests/ProfileData/CoverageMappingTest.cpp b/llvm/unittests/ProfileData/CoverageMappingTest.cpp
index f199cc7a2b2..6535d68dadc 100644
--- a/llvm/unittests/ProfileData/CoverageMappingTest.cpp
+++ b/llvm/unittests/ProfileData/CoverageMappingTest.cpp
@@ -454,6 +454,44 @@ TEST_P(MaybeSparseCoverageMappingTest, strip_unknown_filename_prefix) {
   ASSERT_EQ("func", Names[0]);
 }
 
+TEST_P(MaybeSparseCoverageMappingTest, dont_detect_false_instantiations) {
+  InstrProfRecord Record1("foo", 0x1234, {10});
+  InstrProfRecord Record2("bar", 0x2345, {20});
+  ProfileWriter.addRecord(std::move(Record1));
+  ProfileWriter.addRecord(std::move(Record2));
+
+  startFunction("foo", 0x1234);
+  addCMR(Counter::getCounter(0), "expanded", 1, 1, 1, 10);
+  addExpansionCMR("main", "expanded", 4, 1, 4, 5);
+
+  startFunction("bar", 0x2345);
+  addCMR(Counter::getCounter(0), "expanded", 1, 1, 1, 10);
+  addExpansionCMR("main", "expanded", 9, 1, 9, 5);
+
+  loadCoverageMapping();
+
+  std::vector<const FunctionRecord *> Instantiations =
+      LoadedCoverage->getInstantiations("expanded");
+  ASSERT_TRUE(Instantiations.empty());
+}
+
+TEST_P(MaybeSparseCoverageMappingTest, load_coverage_for_expanded_file) {
+  InstrProfRecord Record("func", 0x1234, {10});
+  ProfileWriter.addRecord(std::move(Record));
+
+  startFunction("func", 0x1234);
+  addCMR(Counter::getCounter(0), "expanded", 1, 1, 1, 10);
+  addExpansionCMR("main", "expanded", 4, 1, 4, 5);
+
+  loadCoverageMapping();
+
+  CoverageData Data = LoadedCoverage->getCoverageForFile("expanded");
+  std::vector<CoverageSegment> Segments(Data.begin(), Data.end());
+  ASSERT_EQ(2U, Segments.size());
+  EXPECT_EQ(CoverageSegment(1, 1, 10, true), Segments[0]);
+  EXPECT_EQ(CoverageSegment(1, 10, false), Segments[1]);
+}
+
 INSTANTIATE_TEST_CASE_P(MaybeSparse, MaybeSparseCoverageMappingTest,
                         ::testing::Bool());