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				https://github.com/c64scene-ar/llvm-6502.git
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	solution but it is a small step towards removing the horror that is TargetAsmInfo. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135237 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			259 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			259 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===- lib/MC/MCWin64EH.cpp - MCWin64EH implementation --------------------===//
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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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| #include "llvm/MC/MCWin64EH.h"
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| #include "llvm/MC/MCStreamer.h"
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| #include "llvm/MC/MCContext.h"
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| #include "llvm/MC/MCSymbol.h"
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| #include "llvm/MC/MCSectionCOFF.h"
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| #include "llvm/MC/MCExpr.h"
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| #include "llvm/Target/TargetAsmInfo.h"
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| 
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| namespace llvm {
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| 
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| // NOTE: All relocations generated here are 4-byte image-relative.
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| 
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| static uint8_t CountOfUnwindCodes(std::vector<MCWin64EHInstruction> &instArray){
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|   uint8_t count = 0;
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|   for (std::vector<MCWin64EHInstruction>::const_iterator I = instArray.begin(),
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|        E = instArray.end(); I != E; ++I) {
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|     switch (I->getOperation()) {
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|     case Win64EH::UOP_PushNonVol:
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|     case Win64EH::UOP_AllocSmall:
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|     case Win64EH::UOP_SetFPReg:
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|     case Win64EH::UOP_PushMachFrame:
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|       count += 1;
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|       break;
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|     case Win64EH::UOP_SaveNonVol:
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|     case Win64EH::UOP_SaveXMM128:
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|       count += 2;
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|       break;
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|     case Win64EH::UOP_SaveNonVolBig:
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|     case Win64EH::UOP_SaveXMM128Big:
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|       count += 3;
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|       break;
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|     case Win64EH::UOP_AllocLarge:
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|       if (I->getSize() > 512*1024-8)
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|         count += 3;
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|       else
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|         count += 2;
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|       break;
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|     }
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|   }
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|   return count;
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| }
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| 
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| static void EmitAbsDifference(MCStreamer &streamer, MCSymbol *lhs,
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|                               MCSymbol *rhs) {
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|   MCContext &context = streamer.getContext();
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|   const MCExpr *diff = MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(
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|                                                                   lhs, context),
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|                                                MCSymbolRefExpr::Create(
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|                                                                   rhs, context),
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|                                                context);
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|   streamer.EmitAbsValue(diff, 1);
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| 
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| }
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| 
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| static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
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|                            MCWin64EHInstruction &inst) {
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|   uint8_t b1, b2;
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|   uint16_t w;
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|   b2 = (inst.getOperation() & 0x0F);
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|   switch (inst.getOperation()) {
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|   case Win64EH::UOP_PushNonVol:
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|     EmitAbsDifference(streamer, inst.getLabel(), begin);
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|     b2 |= (inst.getRegister() & 0x0F) << 4;
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|     streamer.EmitIntValue(b2, 1);
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|     break;
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|   case Win64EH::UOP_AllocLarge:
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|     EmitAbsDifference(streamer, inst.getLabel(), begin);
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|     if (inst.getSize() > 512*1024-8) {
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|       b2 |= 0x10;
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|       streamer.EmitIntValue(b2, 1);
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|       w = inst.getSize() & 0xFFF8;
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|       streamer.EmitIntValue(w, 2);
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|       w = inst.getSize() >> 16;
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|     } else {
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|       streamer.EmitIntValue(b2, 1);
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|       w = inst.getSize() >> 3;
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|     }
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|     streamer.EmitIntValue(w, 2);
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|     break;
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|   case Win64EH::UOP_AllocSmall:
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|     b2 |= (((inst.getSize()-8) >> 3) & 0x0F) << 4;
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|     EmitAbsDifference(streamer, inst.getLabel(), begin);
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|     streamer.EmitIntValue(b2, 1);
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|     break;
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|   case Win64EH::UOP_SetFPReg:
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|     b1 = inst.getOffset() & 0xF0;
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|     streamer.EmitIntValue(b1, 1);
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|     streamer.EmitIntValue(b2, 1);
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|     break;
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|   case Win64EH::UOP_SaveNonVol:
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|   case Win64EH::UOP_SaveXMM128:
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|     b2 |= (inst.getRegister() & 0x0F) << 4;
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|     EmitAbsDifference(streamer, inst.getLabel(), begin);
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|     streamer.EmitIntValue(b2, 1);
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|     w = inst.getOffset() >> 3;
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|     if (inst.getOperation() == Win64EH::UOP_SaveXMM128)
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|       w >>= 1;
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|     streamer.EmitIntValue(w, 2);
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|     break;
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|   case Win64EH::UOP_SaveNonVolBig:
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|   case Win64EH::UOP_SaveXMM128Big:
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|     b2 |= (inst.getRegister() & 0x0F) << 4;
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|     EmitAbsDifference(streamer, inst.getLabel(), begin);
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|     streamer.EmitIntValue(b2, 1);
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|     if (inst.getOperation() == Win64EH::UOP_SaveXMM128Big)
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|       w = inst.getOffset() & 0xFFF0;
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|     else
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|       w = inst.getOffset() & 0xFFF8;
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|     streamer.EmitIntValue(w, 2);
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|     w = inst.getOffset() >> 16;
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|     streamer.EmitIntValue(w, 2);
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|     break;
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|   case Win64EH::UOP_PushMachFrame:
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|     if (inst.isPushCodeFrame())
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|       b2 |= 0x10;
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|     EmitAbsDifference(streamer, inst.getLabel(), begin);
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|     streamer.EmitIntValue(b2, 1);
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|     break;
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|   }
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| }
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| 
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| static void EmitRuntimeFunction(MCStreamer &streamer,
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|                                 const MCWin64EHUnwindInfo *info) {
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|   MCContext &context = streamer.getContext();
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| 
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|   streamer.EmitValueToAlignment(4);
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|   streamer.EmitValue(MCSymbolRefExpr::Create(info->Begin, context), 4);
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|   streamer.EmitValue(MCSymbolRefExpr::Create(info->End, context), 4);
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|   streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol, context), 4);
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| }
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| 
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| static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
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|   // If this UNWIND_INFO already has a symbol, it's already been emitted.
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|   if (info->Symbol) return;
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| 
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|   MCContext &context = streamer.getContext();
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|   streamer.EmitValueToAlignment(4);
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|   // Upper 3 bits are the version number (currently 1).
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|   uint8_t flags = 0x01;
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|   info->Symbol = context.CreateTempSymbol();
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|   streamer.EmitLabel(info->Symbol);
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| 
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|   if (info->ChainedParent)
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|     flags |= Win64EH::UNW_ChainInfo << 3;
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|   else {
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|     if (info->HandlesUnwind)
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|       flags |= Win64EH::UNW_TerminateHandler << 3;
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|     if (info->HandlesExceptions)
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|       flags |= Win64EH::UNW_ExceptionHandler << 3;
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|   }
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|   streamer.EmitIntValue(flags, 1);
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| 
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|   if (info->PrologEnd)
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|     EmitAbsDifference(streamer, info->PrologEnd, info->Begin);
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|   else
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|     streamer.EmitIntValue(0, 1);
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| 
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|   uint8_t numCodes = CountOfUnwindCodes(info->Instructions);
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|   streamer.EmitIntValue(numCodes, 1);
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| 
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|   uint8_t frame = 0;
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|   if (info->LastFrameInst >= 0) {
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|     MCWin64EHInstruction &frameInst = info->Instructions[info->LastFrameInst];
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|     assert(frameInst.getOperation() == Win64EH::UOP_SetFPReg);
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|     frame = (frameInst.getRegister() & 0x0F) |
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|             (frameInst.getOffset() & 0xF0);
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|   }
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|   streamer.EmitIntValue(frame, 1);
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| 
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|   // Emit unwind instructions (in reverse order).
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|   uint8_t numInst = info->Instructions.size();
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|   for (uint8_t c = 0; c < numInst; ++c) {
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|     MCWin64EHInstruction inst = info->Instructions.back();
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|     info->Instructions.pop_back();
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|     EmitUnwindCode(streamer, info->Begin, inst);
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|   }
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| 
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|   if (flags & (Win64EH::UNW_ChainInfo << 3))
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|     EmitRuntimeFunction(streamer, info->ChainedParent);
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|   else if (flags &
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|            ((Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler) << 3))
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|     streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
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|                        4);
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|   else if (numCodes < 2) {
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|     // The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not
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|     // a chained unwind info, if there is no handler, and if there are fewer
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|     // than 2 slots used in the unwind code array, we have to pad to 8 bytes.
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|     if (numCodes == 1)
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|       streamer.EmitIntValue(0, 2);
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|     else
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|       streamer.EmitIntValue(0, 4);
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|   }
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| }
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| 
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| StringRef MCWin64EHUnwindEmitter::GetSectionSuffix(const MCSymbol *func) {
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|   if (!func || !func->isInSection()) return "";
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|   const MCSection *section = &func->getSection();
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|   const MCSectionCOFF *COFFSection;
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|   if ((COFFSection = dyn_cast<MCSectionCOFF>(section))) {
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|     StringRef name = COFFSection->getSectionName();
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|     size_t dollar = name.find('$');
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|     size_t dot = name.find('.', 1);
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|     if (dollar == StringRef::npos && dot == StringRef::npos)
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|       return "";
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|     if (dot == StringRef::npos)
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|       return name.substr(dollar);
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|     if (dollar == StringRef::npos || dot < dollar)
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|       return name.substr(dot);
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|     return name.substr(dollar);
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|   }
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|   return "";
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| }
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| 
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| void MCWin64EHUnwindEmitter::EmitUnwindInfo(MCStreamer &streamer,
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|                                             MCWin64EHUnwindInfo *info) {
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|   // Switch sections (the static function above is meant to be called from
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|   // here and from Emit().
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|   MCContext &context = streamer.getContext();
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|   const TargetAsmInfo &TAI = context.getTargetAsmInfo();
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|   const MCSection *xdataSect =
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|     TAI.getWin64EHTableSection(GetSectionSuffix(info->Function));
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|   streamer.SwitchSection(xdataSect);
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| 
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|   llvm::EmitUnwindInfo(streamer, info);
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| }
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| 
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| void MCWin64EHUnwindEmitter::Emit(MCStreamer &streamer) {
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|   MCContext &context = streamer.getContext();
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|   // Emit the unwind info structs first.
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|   const TargetAsmInfo &TAI = context.getTargetAsmInfo();
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|   for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i) {
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|     MCWin64EHUnwindInfo &info = streamer.getW64UnwindInfo(i);
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|     const MCSection *xdataSect =
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|       TAI.getWin64EHTableSection(GetSectionSuffix(info.Function));
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|     streamer.SwitchSection(xdataSect);
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|     llvm::EmitUnwindInfo(streamer, &info);
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|   }
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|   // Now emit RUNTIME_FUNCTION entries.
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|   for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i) {
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|     MCWin64EHUnwindInfo &info = streamer.getW64UnwindInfo(i);
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|     const MCSection *pdataSect =
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|       TAI.getWin64EHFuncTableSection(GetSectionSuffix(info.Function));
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|     streamer.SwitchSection(pdataSect);
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|     EmitRuntimeFunction(streamer, &info);
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|   }
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| }
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| 
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| } // End of namespace llvm
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| 
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