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https://github.com/c64scene-ar/llvm-6502.git
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adcb2d1636
This makes the opcode an opaque value (unsigned int) rather than the enumeration. This permits the use of target specific operands. Split out the generic type into a MCWinEH header and add a supporting MCWin64EH::Instruction to abstract out the selection of the opcode and construction of the actual instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213221 91177308-0d34-0410-b5e6-96231b3b80d8
292 lines
10 KiB
C++
292 lines
10 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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#include "llvm/MC/MCWin64EH.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectFileInfo.h"
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#include "llvm/MC/MCSectionCOFF.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/Support/Win64EH.h"
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namespace llvm {
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// NOTE: All relocations generated here are 4-byte image-relative.
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static uint8_t CountOfUnwindCodes(std::vector<WinEH::Instruction> &Insns) {
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uint8_t Count = 0;
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for (const auto &I : Insns) {
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switch (static_cast<Win64EH::UnwindOpcodes>(I.Operation)) {
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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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Count += (I.Offset > 512 * 1024 - 8) ? 3 : 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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static void EmitAbsDifference(MCStreamer &Streamer, const MCSymbol *LHS,
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const MCSymbol *RHS) {
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MCContext &Context = Streamer.getContext();
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const MCExpr *Diff =
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MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(LHS, Context),
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MCSymbolRefExpr::Create(RHS, Context), Context);
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Streamer.EmitAbsValue(Diff, 1);
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}
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static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
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WinEH::Instruction &inst) {
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uint8_t b2;
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uint16_t w;
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b2 = (inst.Operation & 0x0F);
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switch (static_cast<Win64EH::UnwindOpcodes>(inst.Operation)) {
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case Win64EH::UOP_PushNonVol:
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EmitAbsDifference(streamer, inst.Label, begin);
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b2 |= (inst.Register & 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.Label, begin);
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if (inst.Offset > 512 * 1024 - 8) {
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b2 |= 0x10;
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streamer.EmitIntValue(b2, 1);
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w = inst.Offset & 0xFFF8;
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streamer.EmitIntValue(w, 2);
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w = inst.Offset >> 16;
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} else {
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streamer.EmitIntValue(b2, 1);
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w = inst.Offset >> 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.Offset - 8) >> 3) & 0x0F) << 4;
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EmitAbsDifference(streamer, inst.Label, 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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EmitAbsDifference(streamer, inst.Label, begin);
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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.Register & 0x0F) << 4;
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EmitAbsDifference(streamer, inst.Label, begin);
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streamer.EmitIntValue(b2, 1);
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w = inst.Offset >> 3;
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if (inst.Operation == 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.Register & 0x0F) << 4;
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EmitAbsDifference(streamer, inst.Label, begin);
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streamer.EmitIntValue(b2, 1);
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if (inst.Operation == Win64EH::UOP_SaveXMM128Big)
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w = inst.Offset & 0xFFF0;
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else
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w = inst.Offset & 0xFFF8;
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streamer.EmitIntValue(w, 2);
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w = inst.Offset >> 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.Offset == 1)
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b2 |= 0x10;
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EmitAbsDifference(streamer, inst.Label, 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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static void EmitSymbolRefWithOfs(MCStreamer &streamer,
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const MCSymbol *Base,
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const MCSymbol *Other) {
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MCContext &Context = streamer.getContext();
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const MCSymbolRefExpr *BaseRef = MCSymbolRefExpr::Create(Base, Context);
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const MCSymbolRefExpr *OtherRef = MCSymbolRefExpr::Create(Other, Context);
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const MCExpr *Ofs = MCBinaryExpr::CreateSub(OtherRef, BaseRef, Context);
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const MCSymbolRefExpr *BaseRefRel = MCSymbolRefExpr::Create(Base,
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MCSymbolRefExpr::VK_COFF_IMGREL32,
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Context);
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streamer.EmitValue(MCBinaryExpr::CreateAdd(BaseRefRel, Ofs, Context), 4);
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}
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static void EmitRuntimeFunction(MCStreamer &streamer,
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const MCWinFrameInfo *info) {
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MCContext &context = streamer.getContext();
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streamer.EmitValueToAlignment(4);
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EmitSymbolRefWithOfs(streamer, info->Function, info->Begin);
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EmitSymbolRefWithOfs(streamer, info->Function, info->End);
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streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol,
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MCSymbolRefExpr::VK_COFF_IMGREL32,
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context), 4);
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}
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static void EmitUnwindInfo(MCStreamer &streamer, MCWinFrameInfo *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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MCContext &context = streamer.getContext();
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streamer.EmitValueToAlignment(4);
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info->Symbol = context.CreateTempSymbol();
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streamer.EmitLabel(info->Symbol);
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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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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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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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uint8_t numCodes = CountOfUnwindCodes(info->Instructions);
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streamer.EmitIntValue(numCodes, 1);
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uint8_t frame = 0;
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if (info->LastFrameInst >= 0) {
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WinEH::Instruction &frameInst = info->Instructions[info->LastFrameInst];
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assert(frameInst.Operation == Win64EH::UOP_SetFPReg);
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frame = (frameInst.Register & 0x0F) | (frameInst.Offset & 0xF0);
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}
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streamer.EmitIntValue(frame, 1);
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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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WinEH::Instruction 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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// For alignment purposes, the instruction array will always have an even
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// number of entries, with the final entry potentially unused (in which case
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// the array will be one longer than indicated by the count of unwind codes
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// field).
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if (numCodes & 1) {
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streamer.EmitIntValue(0, 2);
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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,
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MCSymbolRefExpr::VK_COFF_IMGREL32,
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context), 4);
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else if (numCodes == 0) {
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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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streamer.EmitIntValue(0, 4);
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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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static const MCSection *getWin64EHTableSection(StringRef suffix,
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MCContext &context) {
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if (suffix == "")
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return context.getObjectFileInfo()->getXDataSection();
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return context.getCOFFSection((".xdata"+suffix).str(),
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COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
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COFF::IMAGE_SCN_MEM_READ,
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SectionKind::getDataRel());
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}
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static const MCSection *getWin64EHFuncTableSection(StringRef suffix,
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MCContext &context) {
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if (suffix == "")
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return context.getObjectFileInfo()->getPDataSection();
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return context.getCOFFSection((".pdata"+suffix).str(),
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COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
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COFF::IMAGE_SCN_MEM_READ,
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SectionKind::getDataRel());
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}
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void MCWin64EHUnwindEmitter::EmitUnwindInfo(MCStreamer &streamer,
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MCWinFrameInfo *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 MCSection *xdataSect =
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getWin64EHTableSection(GetSectionSuffix(info->Function), context);
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streamer.SwitchSection(xdataSect);
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llvm::EmitUnwindInfo(streamer, info);
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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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for (const auto &CFI : Streamer.getWinFrameInfos()) {
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const MCSection *XData =
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getWin64EHTableSection(GetSectionSuffix(CFI->Function), Context);
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Streamer.SwitchSection(XData);
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EmitUnwindInfo(Streamer, CFI);
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}
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// Now emit RUNTIME_FUNCTION entries.
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for (const auto &CFI : Streamer.getWinFrameInfos()) {
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const MCSection *PData =
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getWin64EHFuncTableSection(GetSectionSuffix(CFI->Function), Context);
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Streamer.SwitchSection(PData);
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EmitRuntimeFunction(Streamer, CFI);
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}
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}
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} // End of namespace llvm
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