[Remarks] Allow the RemarkStreamer to be used directly with a stream

The filename in the RemarkStreamer should be optional to allow clients
to stream remarks to memory or to existing streams.

This introduces a new overload of `setupOptimizationRemarks`, and avoids
enforcing the presence of a filename at different places.

llvm-svn: 372195

3 files changed, 62 insertions, 19 deletions

diff --git a/llvm/include/llvm/IR/RemarkStreamer.h b/llvm/include/llvm/IR/RemarkStreamer.h
index 7b2fc95d15e..2abf6f99cb0 100644
--- a/llvm/include/llvm/IR/RemarkStreamer.h
+++ b/llvm/include/llvm/IR/RemarkStreamer.h
@@ -25,12 +25,12 @@
 namespace llvm {
 /// Streamer for remarks.
 class RemarkStreamer {
-  /// The filename that the remark diagnostics are emitted to.
-  const std::string Filename;
   /// The regex used to filter remarks based on the passes that emit them.
   Optional<Regex> PassFilter;
   /// The object used to serialize the remarks to a specific format.
   std::unique_ptr<remarks::RemarkSerializer> RemarkSerializer;
+  /// The filename that the remark diagnostics are emitted to.
+  const Optional<std::string> Filename;
 
   /// Convert diagnostics into remark objects.
   /// The lifetime of the members of the result is bound to the lifetime of
@@ -38,10 +38,12 @@ class RemarkStreamer {
   remarks::Remark toRemark(const DiagnosticInfoOptimizationBase &Diag);
 
 public:
-  RemarkStreamer(StringRef Filename,
-                 std::unique_ptr<remarks::RemarkSerializer> RemarkSerializer);
+  RemarkStreamer(std::unique_ptr<remarks::RemarkSerializer> RemarkSerializer,
+                 Optional<StringRef> Filename = None);
   /// Return the filename that the remark diagnostics are emitted to.
-  StringRef getFilename() const { return Filename; }
+  Optional<StringRef> getFilename() const {
+    return Filename ? Optional<StringRef>(*Filename) : None;
+  }
   /// Return stream that the remark diagnostics are emitted to.
   raw_ostream &getStream() { return RemarkSerializer->OS; }
   /// Return the serializer used for this stream.
@@ -84,13 +86,21 @@ struct RemarkSetupFormatError : RemarkSetupErrorInfo<RemarkSetupFormatError> {
   using RemarkSetupErrorInfo<RemarkSetupFormatError>::RemarkSetupErrorInfo;
 };
 
-/// Setup optimization remarks.
+/// Setup optimization remarks that output to a file.
 Expected<std::unique_ptr<ToolOutputFile>>
 setupOptimizationRemarks(LLVMContext &Context, StringRef RemarksFilename,
                          StringRef RemarksPasses, StringRef RemarksFormat,
                          bool RemarksWithHotness,
                          unsigned RemarksHotnessThreshold = 0);
 
+/// Setup optimization remarks that output directly to a raw_ostream.
+/// \p OS is managed by the caller and should be open for writing as long as \p
+/// Context is streaming remarks to it.
+Error setupOptimizationRemarks(LLVMContext &Context, raw_ostream &OS,
+                               StringRef RemarksPasses, StringRef RemarksFormat,
+                               bool RemarksWithHotness,
+                               unsigned RemarksHotnessThreshold = 0);
+
 } // end namespace llvm
 
 #endif // LLVM_IR_REMARKSTREAMER_H
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index ca223f78c16..20c50bb8a2a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1349,15 +1349,18 @@ void AsmPrinter::emitRemarksSection(Module &M) {
     return;
   remarks::RemarkSerializer &RemarkSerializer = RS->getSerializer();
 
-  StringRef FilenameRef = RS->getFilename();
-  SmallString<128> Filename = FilenameRef;
-  sys::fs::make_absolute(Filename);
-  assert(!Filename.empty() && "The filename can't be empty.");
+  Optional<SmallString<128>> Filename;
+  if (Optional<StringRef> FilenameRef = RS->getFilename()) {
+    Filename = *FilenameRef;
+    sys::fs::make_absolute(*Filename);
+    assert(!Filename->empty() && "The filename can't be empty.");
+  }
 
   std::string Buf;
   raw_string_ostream OS(Buf);
   std::unique_ptr<remarks::MetaSerializer> MetaSerializer =
-      RemarkSerializer.metaSerializer(OS, StringRef(Filename));
+      Filename ? RemarkSerializer.metaSerializer(OS, StringRef(*Filename))
+               : RemarkSerializer.metaSerializer(OS);
   MetaSerializer->emit();
 
   // Switch to the right section: .remarks/__remarks.
diff --git a/llvm/lib/IR/RemarkStreamer.cpp b/llvm/lib/IR/RemarkStreamer.cpp
index 73387ecbac1..8a70862de72 100644
--- a/llvm/lib/IR/RemarkStreamer.cpp
+++ b/llvm/lib/IR/RemarkStreamer.cpp
@@ -22,12 +22,10 @@
 using namespace llvm;
 
 RemarkStreamer::RemarkStreamer(
-    StringRef Filename,
-    std::unique_ptr<remarks::RemarkSerializer> RemarkSerializer)
-    : Filename(Filename), PassFilter(),
-      RemarkSerializer(std::move(RemarkSerializer)) {
-  assert(!Filename.empty() && "This needs to be a real filename.");
-}
+    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);
@@ -137,12 +135,13 @@ llvm::setupOptimizationRemarks(LLVMContext &Context, StringRef RemarksFilename,
     return make_error<RemarkSetupFormatError>(std::move(E));
 
   Expected<std::unique_ptr<remarks::RemarkSerializer>> RemarkSerializer =
-      remarks::createRemarkSerializer(*Format, remarks::SerializerMode::Separate, RemarksFile->os());
+      remarks::createRemarkSerializer(
+          *Format, remarks::SerializerMode::Separate, RemarksFile->os());
   if (Error E = RemarkSerializer.takeError())
     return make_error<RemarkSetupFormatError>(std::move(E));
 
   Context.setRemarkStreamer(std::make_unique<RemarkStreamer>(
-      RemarksFilename, std::move(*RemarkSerializer)));
+      std::move(*RemarkSerializer), RemarksFilename));
 
   if (!RemarksPasses.empty())
     if (Error E = Context.getRemarkStreamer()->setFilter(RemarksPasses))
@@ -150,3 +149,34 @@ llvm::setupOptimizationRemarks(LLVMContext &Context, StringRef RemarksFilename,
 
   return std::move(RemarksFile);
 }
+
+Error llvm::setupOptimizationRemarks(LLVMContext &Context, raw_ostream &OS,
+                                     StringRef RemarksPasses,
+                                     StringRef RemarksFormat,
+                                     bool RemarksWithHotness,
+                                     unsigned RemarksHotnessThreshold) {
+  if (RemarksWithHotness)
+    Context.setDiagnosticsHotnessRequested(true);
+
+  if (RemarksHotnessThreshold)
+    Context.setDiagnosticsHotnessThreshold(RemarksHotnessThreshold);
+
+  Expected<remarks::Format> Format = remarks::parseFormat(RemarksFormat);
+  if (Error E = Format.takeError())
+    return make_error<RemarkSetupFormatError>(std::move(E));
+
+  Expected<std::unique_ptr<remarks::RemarkSerializer>> RemarkSerializer =
+      remarks::createRemarkSerializer(*Format,
+                                      remarks::SerializerMode::Separate, OS);
+  if (Error E = RemarkSerializer.takeError())
+    return make_error<RemarkSetupFormatError>(std::move(E));
+
+  Context.setRemarkStreamer(
+      std::make_unique<RemarkStreamer>(std::move(*RemarkSerializer)));
+
+  if (!RemarksPasses.empty())
+    if (Error E = Context.getRemarkStreamer()->setFilter(RemarksPasses))
+      return make_error<RemarkSetupPatternError>(std::move(E));
+
+  return Error::success();
+}