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

1 files changed, 29 insertions, 31 deletions

diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp b/contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
index 57864e4..165b8ee 100644
--- a/contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
+++ b/contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
@@ -40,19 +40,12 @@ using namespace llvm;
 
 #define DEBUG_TYPE "asm-printer"
 
-namespace {
-  struct SrcMgrDiagInfo {
-    const MDNode *LocInfo;
-    LLVMContext::InlineAsmDiagHandlerTy DiagHandler;
-    void *DiagContext;
-  };
-}
-
 /// srcMgrDiagHandler - This callback is invoked when the SourceMgr for an
 /// inline asm has an error in it.  diagInfo is a pointer to the SrcMgrDiagInfo
 /// struct above.
 static void srcMgrDiagHandler(const SMDiagnostic &Diag, void *diagInfo) {
-  SrcMgrDiagInfo *DiagInfo = static_cast<SrcMgrDiagInfo *>(diagInfo);
+  AsmPrinter::SrcMgrDiagInfo *DiagInfo =
+      static_cast<AsmPrinter::SrcMgrDiagInfo *>(diagInfo);
   assert(DiagInfo && "Diagnostic context not passed down?");
 
   // If the inline asm had metadata associated with it, pull out a location
@@ -99,35 +92,34 @@ void AsmPrinter::EmitInlineAsm(StringRef Str, const MCSubtargetInfo &STI,
     return;
   }
 
-  SourceMgr SrcMgr;
-  SrcMgr.setIncludeDirs(MCOptions.IASSearchPaths);
+  if (!DiagInfo) {
+    DiagInfo = make_unique<SrcMgrDiagInfo>();
 
-  SrcMgrDiagInfo DiagInfo;
-
-  // If the current LLVMContext has an inline asm handler, set it in SourceMgr.
-  LLVMContext &LLVMCtx = MMI->getModule()->getContext();
-  bool HasDiagHandler = false;
-  if (LLVMCtx.getInlineAsmDiagnosticHandler() != nullptr) {
-    // If the source manager has an issue, we arrange for srcMgrDiagHandler
-    // to be invoked, getting DiagInfo passed into it.
-    DiagInfo.LocInfo = LocMDNode;
-    DiagInfo.DiagHandler = LLVMCtx.getInlineAsmDiagnosticHandler();
-    DiagInfo.DiagContext = LLVMCtx.getInlineAsmDiagnosticContext();
-    SrcMgr.setDiagHandler(srcMgrDiagHandler, &DiagInfo);
-    HasDiagHandler = true;
+    MCContext &Context = MMI->getContext();
+    Context.setInlineSourceManager(&DiagInfo->SrcMgr);
+
+    LLVMContext &LLVMCtx = MMI->getModule()->getContext();
+    if (LLVMCtx.getInlineAsmDiagnosticHandler()) {
+      DiagInfo->DiagHandler = LLVMCtx.getInlineAsmDiagnosticHandler();
+      DiagInfo->DiagContext = LLVMCtx.getInlineAsmDiagnosticContext();
+      DiagInfo->SrcMgr.setDiagHandler(srcMgrDiagHandler, DiagInfo.get());
+    }
   }
 
+  SourceMgr &SrcMgr = DiagInfo->SrcMgr;
+  SrcMgr.setIncludeDirs(MCOptions.IASSearchPaths);
+  DiagInfo->LocInfo = LocMDNode;
+
   std::unique_ptr<MemoryBuffer> Buffer;
-  if (isNullTerminated)
-    Buffer = MemoryBuffer::getMemBuffer(Str, "<inline asm>");
-  else
-    Buffer = MemoryBuffer::getMemBufferCopy(Str, "<inline asm>");
+  // The inline asm source manager will outlive Str, so make a copy of the
+  // string for SourceMgr to own.
+  Buffer = MemoryBuffer::getMemBufferCopy(Str, "<inline asm>");
 
   // Tell SrcMgr about this buffer, it takes ownership of the buffer.
-  SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
+  unsigned BufNum = SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
 
   std::unique_ptr<MCAsmParser> Parser(
-      createMCAsmParser(SrcMgr, OutContext, *OutStreamer, *MAI));
+      createMCAsmParser(SrcMgr, OutContext, *OutStreamer, *MAI, BufNum));
 
   // We create a new MCInstrInfo here since we might be at the module level
   // and not have a MachineFunction to initialize the TargetInstrInfo from and
@@ -151,7 +143,13 @@ void AsmPrinter::EmitInlineAsm(StringRef Str, const MCSubtargetInfo &STI,
   int Res = Parser->Run(/*NoInitialTextSection*/ true,
                         /*NoFinalize*/ true);
   emitInlineAsmEnd(STI, &TAP->getSTI());
-  if (Res && !HasDiagHandler)
+
+  // LocInfo cannot be used for error generation from the backend.
+  // FIXME: associate LocInfo with the SourceBuffer to improve backend
+  // messages.
+  DiagInfo->LocInfo = nullptr;
+
+  if (Res && !DiagInfo->DiagHandler)
     report_fatal_error("Error parsing inline asm\n");
 }