[llvm-profdata] Add more unit tests to check --output-size-limit feature when compression is enabled

[huangjd]

Summary

Add unit tests for ExtBinary format with compression. This patch doesn't imply there's a bug in the existing implementation,
but as a precaution that planned changes to SampleProfileReader may cause it to break.

[snehasish]

lgtm

llvm/unittests/tools/llvm-profdata/OutputSizeLimitTest.cpp

 /// The main testing routine. After rewriting profiles with size limit, check
 /// the following:
 /// 1. The file size of the new profile is within the size limit.
 /// 2. The new profile is a subset of the old profile, and the content of every
 /// sample in the new profile is unchanged.
 /// Note that even though by default samples with fewest total count are dropped
 /// first, this is not a requirement. Samples can be dropped by any order.
 static ExpectedErrorOr<void *> RunTest(StringRef Input, size_t SizeLimit,
-                                       SampleProfileFormat Format) {
+                                       SampleProfileFormat Format,
+                                       bool Compress = false) {
   // Read Input profile.
   auto FS = vfs::getRealFileSystem();
   LLVMContext Context;
   auto InputBuffer = MemoryBuffer::getMemBuffer(Input);
   DEF_VAR_RETURN_IF_ERROR(
       Reader, SampleProfileReader::create(InputBuffer, Context, *FS));
   RETURN_IF_ERROR(Reader->read());
   SampleProfileMap OldProfiles = Reader->getProfiles();
 
   // Rewrite it to a temp file with size limit.
   TempFile Temp("profile", "afdo", "", true);
   bool isEmpty = false;
   {
     DEF_VAR_RETURN_IF_ERROR(Writer,
                             SampleProfileWriter::create(Temp.path(), Format));
+    if (Compress)
+      Writer->setToCompressAllSections();
     std::error_code EC = Writer->writeWithSizeLimit(OldProfiles, SizeLimit);
     // too_large means no sample could be written because SizeLimit is too
     // small. Otherwise any other error code indicates unexpected failure.
     if (EC == sampleprof_error::too_large)
       isEmpty = true;
     else if (EC)
       return EC;
   }

 
 TEST(TestOutputSizeLimit, TestOutputSizeLimitText) {
   for (size_t OutputSizeLimit :
        {229, 228, 227, 213, 212, 211, 189, 188, 187, 186, 150})
     ASSERT_THAT_EXPECTED(
         RunTest(Input1, OutputSizeLimit, llvm::sampleprof::SPF_Text),
         Succeeded());
 }
+
+TEST(TestOutputSizeLimit, TestOutputSizeLimitExtBinaryCompressed) {
+  for (size_t OutputSizeLimit :
+       {507, 506, 505, 494, 493, 492, 483, 482, 481, 480})
+    ASSERT_THAT_EXPECTED(RunTest(Input1, OutputSizeLimit,
+                                 llvm::sampleprof::SPF_Ext_Binary, true),
+                         Succeeded());
+}