[SampleFDO] Add FunctionOffsetTable in compact binary format profile.

The patch saves a function offset table which maps function name index to the
offset of its function profile to the start of the binary profile. By using
the function offset table, for those function profiles which will not be used
when compiling a module, the profile reader does't have to read them. For
profile size around 10~20M, it saves ~10% compile time.

Differential Revision: https://reviews.llvm.org/D51863

llvm-svn: 342283

1 files changed, 14 insertions, 6 deletions

diff --git a/llvm/unittests/ProfileData/SampleProfTest.cpp b/llvm/unittests/ProfileData/SampleProfTest.cpp
index 3ebfd0e500f..6c669445a2b 100644
--- a/llvm/unittests/ProfileData/SampleProfTest.cpp
+++ b/llvm/unittests/ProfileData/SampleProfTest.cpp
@@ -36,14 +36,17 @@ static ::testing::AssertionResult NoError(std::error_code EC) {
 namespace {
 
 struct SampleProfTest : ::testing::Test {
-  std::string Data;
   LLVMContext Context;
+  std::string Profile;
   std::unique_ptr<raw_ostream> OS;
   std::unique_ptr<SampleProfileWriter> Writer;
   std::unique_ptr<SampleProfileReader> Reader;
+  std::error_code EC;
 
   SampleProfTest()
-      : Data(), OS(new raw_string_ostream(Data)), Writer(), Reader() {}
+      : Profile("profile"),
+        OS(new raw_fd_ostream(Profile, EC, sys::fs::F_None)), Writer(),
+        Reader() {}
 
   void createWriter(SampleProfileFormat Format) {
     auto WriterOrErr = SampleProfileWriter::create(OS, Format);
@@ -51,10 +54,11 @@ struct SampleProfTest : ::testing::Test {
     Writer = std::move(WriterOrErr.get());
   }
 
-  void readProfile(std::unique_ptr<MemoryBuffer> &Profile) {
+  void readProfile(const Module &M) {
     auto ReaderOrErr = SampleProfileReader::create(Profile, Context);
     ASSERT_TRUE(NoError(ReaderOrErr.getError()));
     Reader = std::move(ReaderOrErr.get());
+    Reader->collectFuncsToUse(M);
   }
 
   void testRoundTrip(SampleProfileFormat Format) {
@@ -83,6 +87,12 @@ struct SampleProfTest : ::testing::Test {
     BarSamples.addCalledTargetSamples(1, 0, MconstructName, 1000);
     BarSamples.addCalledTargetSamples(1, 0, StringviewName, 437);
 
+    Module M("my_module", Context);
+    FunctionType *fn_type =
+        FunctionType::get(Type::getVoidTy(Context), {}, false);
+    M.getOrInsertFunction(FooName, fn_type);
+    M.getOrInsertFunction(BarName, fn_type);
+
     StringMap<FunctionSamples> Profiles;
     Profiles[FooName] = std::move(FooSamples);
     Profiles[BarName] = std::move(BarSamples);
@@ -93,8 +103,7 @@ struct SampleProfTest : ::testing::Test {
 
     Writer->getOutputStream().flush();
 
-    auto Profile = MemoryBuffer::getMemBufferCopy(Data);
-    readProfile(Profile);
+    readProfile(M);
 
     EC = Reader->read();
     ASSERT_TRUE(NoError(EC));
@@ -164,7 +173,6 @@ struct SampleProfTest : ::testing::Test {
     delete PS;
 
     // Test that summary can be attached to and read back from module.
-    Module M("my_module", Context);
     M.setProfileSummary(MD);
     MD = M.getProfileSummary();
     ASSERT_TRUE(MD);