Reland: [Remarks] Add an LLVM-bitstream-based remark serializer

Add a new serializer, using a binary format based on the LLVM bitstream
format.

This format provides a way to serialize the remarks in two modes:

1) Separate mode: the metadata is separate from the remark entries.
2) Standalone mode: the metadata and the remark entries are in the same
file.

The format contains:

* a meta block: container version, container type, string table,
external file path, remark version
* a remark block: type, remark name, pass name, function name, debug
file, debug line, debug column, hotness, arguments (key, value, debug
file, debug line, debug column)

A string table is required for this format, which will be dumped in the
meta block to be consumed before parsing the remark blocks.

On clang itself, we noticed a size reduction of 13.4x compared to YAML,
and a compile-time reduction of between 1.7% and 3.5% on CTMark.

Differential Revision: https://reviews.llvm.org/D63466

Original llvm-svn: 367364
Revert llvm-svn: 367370

llvm-svn: 367372

1 files changed, 48 insertions, 0 deletions

diff --git a/llvm/unittests/Remarks/BitstreamRemarksFormatTest.cpp b/llvm/unittests/Remarks/BitstreamRemarksFormatTest.cpp
new file mode 100644
index 00000000000..ea61691f4c8
--- /dev/null
+++ b/llvm/unittests/Remarks/BitstreamRemarksFormatTest.cpp
@@ -0,0 +1,48 @@
+//===- unittest/Support/BitstreamRemarksFormatTest.cpp - BitCodes tests ---===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Remarks/BitstreamRemarkContainer.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+// The goal for this test is to observe test failures and carefully update the
+// constants when they change.
+
+// This should not change over time.
+TEST(BitstreamRemarksFormat, Magic) {
+  EXPECT_EQ(remarks::ContainerMagic, "RMRK");
+}
+
+// This should be updated whenever any of the tests below are modified.
+TEST(BitstreamRemarksFormat, ContainerVersion) {
+  EXPECT_EQ(remarks::CurrentContainerVersion, 0UL);
+}
+
+// The values of the current blocks should not change over time.
+// When adding new blocks, make sure to append them to the enum.
+TEST(BitstreamRemarksFormat, BlockIDs) {
+  EXPECT_EQ(remarks::META_BLOCK_ID, 8);
+  EXPECT_EQ(remarks::REMARK_BLOCK_ID, 9);
+}
+
+// The values of the current records should not change over time.
+// When adding new records, make sure to append them to the enum.
+TEST(BitstreamRemarksFormat, RecordIDs) {
+  EXPECT_EQ(remarks::RECORD_FIRST, 1);
+  EXPECT_EQ(remarks::RECORD_META_CONTAINER_INFO, 1);
+  EXPECT_EQ(remarks::RECORD_META_REMARK_VERSION, 2);
+  EXPECT_EQ(remarks::RECORD_META_STRTAB, 3);
+  EXPECT_EQ(remarks::RECORD_META_EXTERNAL_FILE, 4);
+  EXPECT_EQ(remarks::RECORD_REMARK_HEADER, 5);
+  EXPECT_EQ(remarks::RECORD_REMARK_DEBUG_LOC, 6);
+  EXPECT_EQ(remarks::RECORD_REMARK_HOTNESS, 7);
+  EXPECT_EQ(remarks::RECORD_REMARK_ARG_WITH_DEBUGLOC, 8);
+  EXPECT_EQ(remarks::RECORD_REMARK_ARG_WITHOUT_DEBUGLOC, 9);
+  EXPECT_EQ(remarks::RECORD_LAST, 9);
+}