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	This reverts commit 0037b6bcbc874aa1b93d7ce3ad8dba3753ee2d9d (r237827). David Blaikie suggested some alternatives to this which are better. Reverting to apply a better solution later. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237849 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			302 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			302 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===-- AsmPrinterDwarf.cpp - AsmPrinter Dwarf Support --------------------===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file implements the Dwarf emissions parts of AsmPrinter.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "ByteStreamer.h"
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| #include "DwarfDebug.h"
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| #include "DwarfExpression.h"
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| #include "llvm/ADT/Twine.h"
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| #include "llvm/CodeGen/AsmPrinter.h"
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| #include "llvm/CodeGen/DIE.h"
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| #include "llvm/CodeGen/MachineFunction.h"
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| #include "llvm/CodeGen/MachineModuleInfo.h"
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| #include "llvm/IR/DataLayout.h"
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| #include "llvm/MC/MCAsmInfo.h"
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| #include "llvm/MC/MCRegisterInfo.h"
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| #include "llvm/MC/MCSection.h"
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| #include "llvm/MC/MCStreamer.h"
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| #include "llvm/MC/MCSymbol.h"
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| #include "llvm/MC/MachineLocation.h"
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| #include "llvm/Support/Dwarf.h"
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| #include "llvm/Support/ErrorHandling.h"
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| #include "llvm/Target/TargetLoweringObjectFile.h"
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| #include "llvm/Target/TargetMachine.h"
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| #include "llvm/Target/TargetSubtargetInfo.h"
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| using namespace llvm;
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| 
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| #define DEBUG_TYPE "asm-printer"
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| 
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| //===----------------------------------------------------------------------===//
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| // Dwarf Emission Helper Routines
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| //===----------------------------------------------------------------------===//
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| 
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| /// EmitSLEB128 - emit the specified signed leb128 value.
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| void AsmPrinter::EmitSLEB128(int64_t Value, const char *Desc) const {
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|   if (isVerbose() && Desc)
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|     OutStreamer->AddComment(Desc);
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| 
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|   OutStreamer->EmitSLEB128IntValue(Value);
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| }
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| 
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| /// EmitULEB128 - emit the specified signed leb128 value.
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| void AsmPrinter::EmitULEB128(uint64_t Value, const char *Desc,
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|                              unsigned PadTo) const {
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|   if (isVerbose() && Desc)
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|     OutStreamer->AddComment(Desc);
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| 
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|   OutStreamer->EmitULEB128IntValue(Value, PadTo);
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| }
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| 
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| /// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value.
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| void AsmPrinter::EmitCFAByte(unsigned Val) const {
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|   if (isVerbose()) {
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|     if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset + 64)
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|       OutStreamer->AddComment("DW_CFA_offset + Reg (" +
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|                               Twine(Val - dwarf::DW_CFA_offset) + ")");
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|     else
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|       OutStreamer->AddComment(dwarf::CallFrameString(Val));
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|   }
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|   OutStreamer->EmitIntValue(Val, 1);
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| }
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| 
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| static const char *DecodeDWARFEncoding(unsigned Encoding) {
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|   switch (Encoding) {
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|   case dwarf::DW_EH_PE_absptr:
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|     return "absptr";
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|   case dwarf::DW_EH_PE_omit:
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|     return "omit";
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|   case dwarf::DW_EH_PE_pcrel:
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|     return "pcrel";
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|   case dwarf::DW_EH_PE_udata4:
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|     return "udata4";
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|   case dwarf::DW_EH_PE_udata8:
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|     return "udata8";
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|   case dwarf::DW_EH_PE_sdata4:
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|     return "sdata4";
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|   case dwarf::DW_EH_PE_sdata8:
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|     return "sdata8";
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|   case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
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|     return "pcrel udata4";
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|   case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
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|     return "pcrel sdata4";
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|   case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
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|     return "pcrel udata8";
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|   case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
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|     return "pcrel sdata8";
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|   case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4
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|       :
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|     return "indirect pcrel udata4";
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|   case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
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|       :
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|     return "indirect pcrel sdata4";
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|   case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8
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|       :
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|     return "indirect pcrel udata8";
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|   case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8
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|       :
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|     return "indirect pcrel sdata8";
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|   }
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| 
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|   return "<unknown encoding>";
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| }
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| 
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| /// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an
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| /// encoding.  If verbose assembly output is enabled, we output comments
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| /// describing the encoding.  Desc is an optional string saying what the
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| /// encoding is specifying (e.g. "LSDA").
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| void AsmPrinter::EmitEncodingByte(unsigned Val, const char *Desc) const {
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|   if (isVerbose()) {
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|     if (Desc)
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|       OutStreamer->AddComment(Twine(Desc) + " Encoding = " +
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|                               Twine(DecodeDWARFEncoding(Val)));
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|     else
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|       OutStreamer->AddComment(Twine("Encoding = ") + DecodeDWARFEncoding(Val));
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|   }
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| 
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|   OutStreamer->EmitIntValue(Val, 1);
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| }
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| 
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| /// GetSizeOfEncodedValue - Return the size of the encoding in bytes.
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| unsigned AsmPrinter::GetSizeOfEncodedValue(unsigned Encoding) const {
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|   if (Encoding == dwarf::DW_EH_PE_omit)
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|     return 0;
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| 
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|   switch (Encoding & 0x07) {
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|   default:
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|     llvm_unreachable("Invalid encoded value.");
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|   case dwarf::DW_EH_PE_absptr:
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|     return TM.getDataLayout()->getPointerSize();
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|   case dwarf::DW_EH_PE_udata2:
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|     return 2;
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|   case dwarf::DW_EH_PE_udata4:
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|     return 4;
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|   case dwarf::DW_EH_PE_udata8:
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|     return 8;
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|   }
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| }
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| 
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| void AsmPrinter::EmitTTypeReference(const GlobalValue *GV,
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|                                     unsigned Encoding) const {
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|   if (GV) {
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|     const TargetLoweringObjectFile &TLOF = getObjFileLowering();
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| 
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|     const MCExpr *Exp =
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|         TLOF.getTTypeGlobalReference(GV, Encoding, *Mang, TM, MMI,
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|                                      *OutStreamer);
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|     OutStreamer->EmitValue(Exp, GetSizeOfEncodedValue(Encoding));
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|   } else
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|     OutStreamer->EmitIntValue(0, GetSizeOfEncodedValue(Encoding));
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| }
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| 
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| /// EmitSectionOffset - Emit the 4-byte offset of Label from the start of its
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| /// section.  This can be done with a special directive if the target supports
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| /// it (e.g. cygwin) or by emitting it as an offset from a label at the start
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| /// of the section.
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| ///
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| /// SectionLabel is a temporary label emitted at the start of the section that
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| /// Label lives in.
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| void AsmPrinter::emitSectionOffset(const MCSymbol *Label) const {
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|   // On COFF targets, we have to emit the special .secrel32 directive.
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|   if (MAI->needsDwarfSectionOffsetDirective()) {
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|     OutStreamer->EmitCOFFSecRel32(Label);
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|     return;
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|   }
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| 
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|   // If the format uses relocations with dwarf, refer to the symbol directly.
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|   if (MAI->doesDwarfUseRelocationsAcrossSections()) {
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|     OutStreamer->EmitSymbolValue(Label, 4);
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|     return;
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|   }
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| 
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|   // Otherwise, emit it as a label difference from the start of the section.
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|   EmitLabelDifference(Label, Label->getSection().getBeginSymbol(), 4);
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| }
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| 
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| /// EmitDwarfRegOp - Emit dwarf register operation.
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| void AsmPrinter::EmitDwarfRegOp(ByteStreamer &Streamer,
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|                                 const MachineLocation &MLoc) const {
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|   DebugLocDwarfExpression Expr(*MF->getSubtarget().getRegisterInfo(),
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|                                getDwarfDebug()->getDwarfVersion(), Streamer);
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|   const MCRegisterInfo *MRI = MMI->getContext().getRegisterInfo();
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|   int Reg = MRI->getDwarfRegNum(MLoc.getReg(), false);
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|   if (Reg < 0) {
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|     // We assume that pointers are always in an addressable register.
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|     if (MLoc.isIndirect())
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|       // FIXME: We have no reasonable way of handling errors in here. The
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|       // caller might be in the middle of a dwarf expression. We should
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|       // probably assert that Reg >= 0 once debug info generation is more
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|       // mature.
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|       return Expr.EmitOp(dwarf::DW_OP_nop,
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|                          "nop (could not find a dwarf register number)");
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| 
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|     // Attempt to find a valid super- or sub-register.
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|     if (!Expr.AddMachineRegPiece(MLoc.getReg()))
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|       Expr.EmitOp(dwarf::DW_OP_nop,
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|                   "nop (could not find a dwarf register number)");
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|     return;
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|   }
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| 
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|   if (MLoc.isIndirect())
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|     Expr.AddRegIndirect(Reg, MLoc.getOffset());
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|   else
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|     Expr.AddReg(Reg);
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| }
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| 
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| //===----------------------------------------------------------------------===//
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| // Dwarf Lowering Routines
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| //===----------------------------------------------------------------------===//
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| 
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| void AsmPrinter::emitCFIInstruction(const MCCFIInstruction &Inst) const {
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|   switch (Inst.getOperation()) {
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|   default:
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|     llvm_unreachable("Unexpected instruction");
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|   case MCCFIInstruction::OpDefCfaOffset:
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|     OutStreamer->EmitCFIDefCfaOffset(Inst.getOffset());
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|     break;
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|   case MCCFIInstruction::OpDefCfa:
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|     OutStreamer->EmitCFIDefCfa(Inst.getRegister(), Inst.getOffset());
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|     break;
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|   case MCCFIInstruction::OpDefCfaRegister:
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|     OutStreamer->EmitCFIDefCfaRegister(Inst.getRegister());
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|     break;
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|   case MCCFIInstruction::OpOffset:
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|     OutStreamer->EmitCFIOffset(Inst.getRegister(), Inst.getOffset());
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|     break;
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|   case MCCFIInstruction::OpRegister:
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|     OutStreamer->EmitCFIRegister(Inst.getRegister(), Inst.getRegister2());
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|     break;
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|   case MCCFIInstruction::OpWindowSave:
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|     OutStreamer->EmitCFIWindowSave();
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|     break;
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|   case MCCFIInstruction::OpSameValue:
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|     OutStreamer->EmitCFISameValue(Inst.getRegister());
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|     break;
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|   }
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| }
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| 
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| void AsmPrinter::emitDwarfDIE(const DIE &Die) const {
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|   // Get the abbreviation for this DIE.
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|   const DIEAbbrev &Abbrev = Die.getAbbrev();
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| 
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|   // Emit the code (index) for the abbreviation.
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|   if (isVerbose())
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|     OutStreamer->AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
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|                             "] 0x" + Twine::utohexstr(Die.getOffset()) +
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|                             ":0x" + Twine::utohexstr(Die.getSize()) + " " +
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|                             dwarf::TagString(Abbrev.getTag()));
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|   EmitULEB128(Abbrev.getNumber());
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| 
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|   const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
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|   const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
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| 
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|   // Emit the DIE attribute values.
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|   for (unsigned i = 0, N = Values.size(); i < N; ++i) {
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|     dwarf::Attribute Attr = AbbrevData[i].getAttribute();
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|     dwarf::Form Form = AbbrevData[i].getForm();
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|     assert(Form && "Too many attributes for DIE (check abbreviation)");
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| 
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|     if (isVerbose()) {
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|       OutStreamer->AddComment(dwarf::AttributeString(Attr));
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|       if (Attr == dwarf::DW_AT_accessibility)
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|         OutStreamer->AddComment(dwarf::AccessibilityString(
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|             cast<DIEInteger>(Values[i])->getValue()));
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|     }
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| 
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|     // Emit an attribute using the defined form.
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|     Values[i]->EmitValue(this, Form);
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|   }
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| 
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|   // Emit the DIE children if any.
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|   if (Abbrev.hasChildren()) {
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|     for (auto &Child : Die.getChildren())
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|       emitDwarfDIE(*Child);
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| 
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|     OutStreamer->AddComment("End Of Children Mark");
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|     EmitInt8(0);
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|   }
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| }
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| 
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| void
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| AsmPrinter::emitDwarfAbbrevs(const std::vector<DIEAbbrev *>& Abbrevs) const {
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|   // For each abbrevation.
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|   for (const DIEAbbrev *Abbrev : Abbrevs) {
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|     // Emit the abbrevations code (base 1 index.)
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|     EmitULEB128(Abbrev->getNumber(), "Abbreviation Code");
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| 
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|     // Emit the abbreviations data.
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|     Abbrev->Emit(this);
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|   }
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| 
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|   // Mark end of abbreviations.
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|   EmitULEB128(0, "EOM(3)");
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| }
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