[Remarks] Extend the RemarkStreamer to support other emitters

This extends the RemarkStreamer to allow for other emitters (e.g.
frontends, SIL, etc.) to emit remarks through a common interface.

See changes in llvm/docs/Remarks.rst for motivation and design choices.

Differential Revision: https://reviews.llvm.org/D73676

2 files changed, 73 insertions, 0 deletions

diff --git a/llvm/lib/Remarks/CMakeLists.txt b/llvm/lib/Remarks/CMakeLists.txt
index c0e67f6..c49d321 100644
--- a/llvm/lib/Remarks/CMakeLists.txt
+++ b/llvm/lib/Remarks/CMakeLists.txt
@@ -6,6 +6,7 @@ add_llvm_component_library(LLVMRemarks
   RemarkLinker.cpp
   RemarkParser.cpp
   RemarkSerializer.cpp
+  RemarkStreamer.cpp
   RemarkStringTable.cpp
   YAMLRemarkParser.cpp
   YAMLRemarkSerializer.cpp
diff --git a/llvm/lib/Remarks/RemarkStreamer.cpp b/llvm/lib/Remarks/RemarkStreamer.cpp
new file mode 100644
index 0000000..2f00b8e
--- /dev/null
+++ b/llvm/lib/Remarks/RemarkStreamer.cpp
@@ -0,0 +1,72 @@
+//===- llvm/Remarks/RemarkStreamer.cpp - Remark Streamer -*- C++ --------*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the implementation of the main remark streamer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Remarks/RemarkStreamer.h"
+#include "llvm/Support/CommandLine.h"
+
+using namespace llvm;
+using namespace llvm::remarks;
+
+static cl::opt<cl::boolOrDefault> EnableRemarksSection(
+    "remarks-section",
+    cl::desc(
+        "Emit a section containing remark diagnostics metadata. By default, "
+        "this is enabled for the following formats: yaml-strtab, bitstream."),
+    cl::init(cl::BOU_UNSET), cl::Hidden);
+
+RemarkStreamer::RemarkStreamer(
+    std::unique_ptr<remarks::RemarkSerializer> RemarkSerializer,
+    Optional<StringRef> FilenameIn)
+    : PassFilter(), RemarkSerializer(std::move(RemarkSerializer)),
+      Filename(FilenameIn ? Optional<std::string>(FilenameIn->str()) : None) {}
+
+Error RemarkStreamer::setFilter(StringRef Filter) {
+  Regex R = Regex(Filter);
+  std::string RegexError;
+  if (!R.isValid(RegexError))
+    return createStringError(std::make_error_code(std::errc::invalid_argument),
+                             RegexError.data());
+  PassFilter = std::move(R);
+  return Error::success();
+}
+
+bool RemarkStreamer::matchesFilter(StringRef Str) {
+  if (PassFilter)
+    return PassFilter->match(Str);
+  // No filter means all strings pass.
+  return true;
+}
+
+bool RemarkStreamer::needsSection() const {
+  if (EnableRemarksSection == cl::BOU_TRUE)
+    return true;
+
+  if (EnableRemarksSection == cl::BOU_FALSE)
+    return false;
+
+  assert(EnableRemarksSection == cl::BOU_UNSET);
+
+  // We only need a section if we're in separate mode.
+  if (RemarkSerializer->Mode != remarks::SerializerMode::Separate)
+    return false;
+
+  // Only some formats need a section:
+  // * bitstream
+  // * yaml-strtab
+  switch (RemarkSerializer->SerializerFormat) {
+  case remarks::Format::YAMLStrTab:
+  case remarks::Format::Bitstream:
+    return true;
+  default:
+    return false;
+  }
+}