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//===- lib/MC/MCWin64EH.cpp - MCWin64EH implementation --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCWin64EH.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/Target/TargetAsmInfo.h"
namespace llvm {
// NOTE: All relocations generated here are 4-byte image-relative.
static uint8_t CountOfUnwindCodes(std::vector<MCWin64EHInstruction> &instArray){
uint8_t count = 0;
for (std::vector<MCWin64EHInstruction>::const_iterator I = instArray.begin(),
E = instArray.end(); I != E; ++I) {
switch (I->getOperation()) {
case Win64EH::UOP_PushNonVol:
case Win64EH::UOP_AllocSmall:
case Win64EH::UOP_SetFPReg:
case Win64EH::UOP_PushMachFrame:
count += 1;
case Win64EH::UOP_SaveNonVol:
case Win64EH::UOP_SaveXMM128:
count += 2;
case Win64EH::UOP_SaveNonVolBig:
case Win64EH::UOP_SaveXMM128Big:
count += 3;
case Win64EH::UOP_AllocLarge:
if (I->getSize() > 512*1024-8)
count += 3;
else
count += 2;
}
}
return count;
}
static void EmitUnwindCode(MCStreamer &streamer, MCWin64EHInstruction &inst) {
uint8_t b1, b2;
uint16_t w;
b2 = (inst.getOperation() & 0x0F) << 4;
switch (inst.getOperation()) {
case Win64EH::UOP_PushNonVol:
streamer.EmitIntValue(0, 1);
b2 |= inst.getRegister() & 0x0F;
streamer.EmitIntValue(b2, 1);
break;
case Win64EH::UOP_AllocLarge:
streamer.EmitIntValue(0, 1);
if (inst.getSize() > 512*1024-8) {
b2 |= 1;
streamer.EmitIntValue(b2, 1);
w = inst.getSize() & 0xFFF8;
streamer.EmitIntValue(w, 2);
w = inst.getSize() >> 16;
} else {
streamer.EmitIntValue(b2, 1);
w = inst.getSize() >> 3;
}
streamer.EmitIntValue(w, 2);
break;
case Win64EH::UOP_AllocSmall:
b2 |= (inst.getSize() >> 3) & 0x0F;
streamer.EmitIntValue(0, 1);
streamer.EmitIntValue(b2, 1);
break;
case Win64EH::UOP_SetFPReg:
b1 = inst.getOffset() & 0xF0;
streamer.EmitIntValue(b1, 1);
streamer.EmitIntValue(b2, 1);
break;
case Win64EH::UOP_SaveNonVol:
case Win64EH::UOP_SaveXMM128:
b2 |= inst.getRegister() & 0x0F;
streamer.EmitIntValue(0, 1);
streamer.EmitIntValue(b2, 1);
w = inst.getOffset() >> 3;
if (inst.getOperation() == Win64EH::UOP_SaveXMM128)
w >>= 1;
streamer.EmitIntValue(w, 2);
break;
case Win64EH::UOP_SaveNonVolBig:
case Win64EH::UOP_SaveXMM128Big:
b2 |= inst.getRegister() & 0x0F;
streamer.EmitIntValue(0, 1);
streamer.EmitIntValue(b2, 1);
if (inst.getOperation() == Win64EH::UOP_SaveXMM128Big)
w = inst.getOffset() & 0xFFF0;
else
w = inst.getOffset() & 0xFFF8;
streamer.EmitIntValue(w, 2);
w = inst.getOffset() >> 16;
streamer.EmitIntValue(w, 2);
break;
case Win64EH::UOP_PushMachFrame:
if (inst.isPushCodeFrame())
b2 |= 1;
streamer.EmitIntValue(0, 1);
streamer.EmitIntValue(b2, 1);
break;
}
}
static void EmitRuntimeFunction(MCStreamer &streamer,
const MCWin64EHUnwindInfo *info) {
MCContext &context = streamer.getContext();
streamer.EmitValue(MCSymbolRefExpr::Create(info->Begin, context), 4);
streamer.EmitValue(MCSymbolRefExpr::Create(info->End, context), 4);
streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol, context), 4);
}
static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
// If this UNWIND_INFO already has a symbol, it's already been emitted.
if (info->Symbol) return;
MCContext &context = streamer.getContext();
// Upper 3 bits are the version number (currently 1).
uint8_t flags = 0x20;
info->Symbol = context.CreateTempSymbol();
streamer.EmitLabel(info->Symbol);
if (info->ChainedParent)
flags |= Win64EH::UNW_ChainInfo;
else {
if (info->HandlesUnwind)
flags |= Win64EH::UNW_TerminateHandler;
if (info->HandlesExceptions)
flags |= Win64EH::UNW_ExceptionHandler;
}
streamer.EmitIntValue(flags, 1);
// Build up the prolog size expression.
const MCExpr *prologSize = MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(
info->PrologEnd, context),
MCSymbolRefExpr::Create(
info->Begin, context),
context);
streamer.EmitAbsValue(prologSize, 1);
uint8_t numCodes = CountOfUnwindCodes(info->Instructions);
streamer.EmitIntValue(numCodes, 1);
uint8_t frame = 0;
if (info->LastFrameInst >= 0) {
MCWin64EHInstruction &frameInst = info->Instructions[info->LastFrameInst];
assert(frameInst.getOperation() == Win64EH::UOP_SetFPReg);
frame = ((frameInst.getRegister() & 0x0F) << 4) |
((frameInst.getOffset() >> 4) & 0x0F);
}
streamer.EmitIntValue(frame, 1);
// Emit unwind instructions (in reverse order).
uint8_t numInst = info->Instructions.size();
for (uint8_t c = 0; c < numInst; ++c) {
MCWin64EHInstruction inst = info->Instructions.back();
info->Instructions.pop_back();
EmitUnwindCode(streamer, inst);
}
if (flags & Win64EH::UNW_ChainInfo)
EmitRuntimeFunction(streamer, info->ChainedParent);
else if (flags &(Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler))
streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
4);
}
void MCWin64EHUnwindEmitter::EmitUnwindInfo(MCStreamer &streamer,
MCWin64EHUnwindInfo *info) {
// Switch sections (the static function above is meant to be called from
// here and from Emit().
MCContext &context = streamer.getContext();
const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
const MCSection *xdataSect = asmInfo.getWin64EHTableSection();
streamer.SwitchSection(xdataSect);
llvm::EmitUnwindInfo(streamer, info);
}
void MCWin64EHUnwindEmitter::Emit(MCStreamer &streamer) {
MCContext &context = streamer.getContext();
// Emit the unwind info structs first.
const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
const MCSection *xdataSect = asmInfo.getWin64EHTableSection();
streamer.SwitchSection(xdataSect);
for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i)
llvm::EmitUnwindInfo(streamer, &streamer.getW64UnwindInfo(i));
// Now emit RUNTIME_FUNCTION entries.
const MCSection *pdataSect = asmInfo.getWin64EHFuncTableSection();
streamer.SwitchSection(pdataSect);
for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i)
EmitRuntimeFunction(streamer, &streamer.getW64UnwindInfo(i));
}
} // End of namespace llvm
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