[Remarks] Add parser for bitstream remarks

The bitstream remark serializer landed in r367372.

This adds a bitstream remark parser that parser bitstream remark files
to llvm::remarks::Remark objects through the RemarkParser interface.

A few interesting things to point out:

* There are parsing helpers to parse the different types of blocks
* The main parsing helper allows us to parse remark metadata and open an
external file containing the encoded remarks
* This adds a dependency from the Remarks library to the BitstreamReader
library
* The testing strategy is to create a remark entry through YAML, parse
it, serialize it to bitstream, parse that back and compare the objects.
* There are close to no tests for malformed bitstream remarks, due to
the lack of textual format for the bitstream format.
* This adds a new C API for parsing bitstream remarks:
LLVMRemarkParserCreateBitstream.
* This bumps the REMARKS_API_VERSION to 1.

Differential Revision: https://reviews.llvm.org/D67134

llvm-svn: 371429

1 files changed, 16 insertions, 1 deletions

diff --git a/llvm/include/llvm-c/Remarks.h b/llvm/include/llvm-c/Remarks.h
index 88eb5120c57..5444aebddd6 100644
--- a/llvm/include/llvm-c/Remarks.h
+++ b/llvm/include/llvm-c/Remarks.h
@@ -30,7 +30,8 @@ extern "C" {
  * @{
  */
 
-#define REMARKS_API_VERSION 0
+// 0 -> 1: Bitstream remarks support.
+#define REMARKS_API_VERSION 1
 
 /**
  * The type of the emitted remark.
@@ -241,6 +242,20 @@ extern LLVMRemarkParserRef LLVMRemarkParserCreateYAML(const void *Buf,
                                                       uint64_t Size);
 
 /**
+ * Creates a remark parser that can be used to parse the buffer located in \p
+ * Buf of size \p Size bytes.
+ *
+ * \p Buf cannot be `NULL`.
+ *
+ * This function should be paired with LLVMRemarkParserDispose() to avoid
+ * leaking resources.
+ *
+ * \since REMARKS_API_VERSION=1
+ */
+extern LLVMRemarkParserRef LLVMRemarkParserCreateBitstream(const void *Buf,
+                                                           uint64_t Size);
+
+/**
  * Returns the next remark in the file.
  *
  * The value pointed to by the return value needs to be disposed using a call to