[mips][micromips] Fix overlaping FDEs error

When compiling static executable for micromips, CFI symbols
are incorrectly labeled as MICROMIPS, which cause
".eh_frame_hdr refers to overlapping FDEs." error.

This patch does not label CFI symbols as MICROMIPS, and FDEs do not
overlap anymore. This patch also exposes another bug, which is fixed
here: https://reviews.llvm.org/D52985

Differential Revision: https://reviews.llvm.org/D52987

llvm-svn: 344511

2 files changed, 24 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp
index 7b9a02503ce..21b01e85096 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp
@@ -15,6 +15,7 @@
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSymbolELF.h"
@@ -53,6 +54,22 @@ void MipsELFStreamer::EmitInstruction(const MCInst &Inst,
   createPendingLabelRelocs();
 }
 
+void MipsELFStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
+  Frame.Begin = getContext().createTempSymbol();
+  MCELFStreamer::EmitLabel(Frame.Begin);
+}
+
+MCSymbol *MipsELFStreamer::EmitCFILabel() {
+  MCSymbol *Label = getContext().createTempSymbol("cfi", true);
+  MCELFStreamer::EmitLabel(Label);
+  return Label;
+}
+
+void MipsELFStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
+  Frame.End = getContext().createTempSymbol();
+  MCELFStreamer::EmitLabel(Frame.End);
+}
+
 void MipsELFStreamer::createPendingLabelRelocs() {
   MipsTargetELFStreamer *ELFTargetStreamer =
       static_cast<MipsTargetELFStreamer *>(getTargetStreamer());
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
index d141f5d77c6..d140201494f 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
@@ -25,6 +25,7 @@ namespace llvm {
 class MCAsmBackend;
 class MCCodeEmitter;
 class MCContext;
+class MCDwarfFrameInfo;
 class MCSubtargetInfo;
 
 class MipsELFStreamer : public MCELFStreamer {
@@ -60,6 +61,12 @@ public:
   void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override;
   void EmitIntValue(uint64_t Value, unsigned Size) override;
 
+  // Overriding these functions allows us to avoid recording of these labels
+  // in EmitLabel and later marking them as microMIPS.
+  void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) override;
+  void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) override;
+  MCSymbol *EmitCFILabel() override;
+
   /// Emits all the option records stored up until the point it's called.
   void EmitMipsOptionRecords();