MFC r317458:

Pull in r294458 from upstream llvm trunk (by Sanne Wouda):

  [Assembler] Enable nicer diagnostics for inline assembly.

  Fixed test.

  Summary:
  Enables source location in diagnostic messages from the backend.
  This is after parsing, during finalization.  This requires the
  SourceMgr, the inline assembly string buffer, and DiagInfo to still
  be alive after EmitInlineAsm returns.

  This patch creates a single SourceMgr for inline assembly inside the
  AsmPrinter.  MCContext gets a pointer to this SourceMgr.  Using one
  SourceMgr per call to EmitInlineAsm would make it difficult for
  MCContext to figure out in which SourceMgr the SMLoc is located,
  while a single SourceMgr can figure it out if it has multiple
  buffers.

  The Str argument to EmitInlineAsm is copied into a buffer and owned
  by the inline asm SourceMgr.  This ensures that DiagHandlers won't
  print garbage.  (Clang emits a "note: instantiated into assembly
  here", which refers to this string.)

  The AsmParser gets destroyed before finalization, which means that
  the DiagHandlers the AsmParser installs into the SourceMgr will be
  stale.  Restore the saved DiagHandlers.

  Since now we're using just one SourceMgr for multiple inline asm
  strings, we need to tell the AsmParser which buffer it needs to parse
  currently.  Hand a buffer id -- returned from SourceMgr::
  AddNewSourceBuffer -- to the AsmParser.

  Reviewers: rnk, grosbach, compnerd, rengolin, rovka, anemet

  Reviewed By: rnk

  Subscribers: llvm-commits

  Differential Revision: https://reviews.llvm.org/D29441

This improves error reporting for some inline assembly constructs that
clang does not approve of: instead of crashing with a "fatal backend
error", it will now show a normal error message, and point out the
location of the problematic assembly.

Reported by:	mmel

2 files changed, 18 insertions, 11 deletions

diff --git a/contrib/llvm/lib/MC/MCContext.cpp b/contrib/llvm/lib/MC/MCContext.cpp
index 4798991..9d2fac2 100644
--- a/contrib/llvm/lib/MC/MCContext.cpp
+++ b/contrib/llvm/lib/MC/MCContext.cpp
@@ -510,13 +510,15 @@ CodeViewContext &MCContext::getCVContext() {
 void MCContext::reportError(SMLoc Loc, const Twine &Msg) {
   HadError = true;
 
-  // If we have a source manager use it. Otherwise just use the generic
-  // report_fatal_error().
-  if (!SrcMgr)
+  // If we have a source manager use it. Otherwise, try using the inline source
+  // manager.
+  // If that fails, use the generic report_fatal_error().
+  if (SrcMgr)
+    SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
+  else if (InlineSrcMgr)
+    InlineSrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
+  else
     report_fatal_error(Msg, false);
-
-  // Use the source manager to print the message.
-  SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
 }
 
 void MCContext::reportFatalError(SMLoc Loc, const Twine &Msg) {
diff --git a/contrib/llvm/lib/MC/MCParser/AsmParser.cpp b/contrib/llvm/lib/MC/MCParser/AsmParser.cpp
index da54155..fd40baa 100644
--- a/contrib/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/contrib/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -209,7 +209,7 @@ private:
 
 public:
   AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
-            const MCAsmInfo &MAI);
+            const MCAsmInfo &MAI, unsigned CB);
   ~AsmParser() override;
 
   bool Run(bool NoInitialTextSection, bool NoFinalize = false) override;
@@ -572,9 +572,9 @@ extern MCAsmParserExtension *createCOFFAsmParser();
 enum { DEFAULT_ADDRSPACE = 0 };
 
 AsmParser::AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
-                     const MCAsmInfo &MAI)
+                     const MCAsmInfo &MAI, unsigned CB = 0)
     : Lexer(MAI), Ctx(Ctx), Out(Out), MAI(MAI), SrcMgr(SM),
-      PlatformParser(nullptr), CurBuffer(SM.getMainFileID()),
+      PlatformParser(nullptr), CurBuffer(CB ? CB : SM.getMainFileID()),
       MacrosEnabledFlag(true), CppHashInfo(), AssemblerDialect(~0U),
       IsDarwin(false), ParsingInlineAsm(false) {
   HadError = false;
@@ -608,6 +608,10 @@ AsmParser::AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
 AsmParser::~AsmParser() {
   assert((HadError || ActiveMacros.empty()) &&
          "Unexpected active macro instantiation!");
+
+  // Restore the saved diagnostics handler and context for use during
+  // finalization.
+  SrcMgr.setDiagHandler(SavedDiagHandler, SavedDiagContext);
 }
 
 void AsmParser::printMacroInstantiations() {
@@ -5518,6 +5522,7 @@ bool parseAssignmentExpression(StringRef Name, bool allow_redef,
 
 /// \brief Create an MCAsmParser instance.
 MCAsmParser *llvm::createMCAsmParser(SourceMgr &SM, MCContext &C,
-                                     MCStreamer &Out, const MCAsmInfo &MAI) {
-  return new AsmParser(SM, C, Out, MAI);
+                                     MCStreamer &Out, const MCAsmInfo &MAI,
+                                     unsigned CB) {
+  return new AsmParser(SM, C, Out, MAI, CB);
 }