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//===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing DWARF exception info into asm files.
//
//===----------------------------------------------------------------------===//
#include "DwarfException.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
DwarfCFIException::DwarfCFIException(AsmPrinter *A)
: EHStreamer(A), shouldEmitPersonality(false), shouldEmitLSDA(false),
shouldEmitMoves(false), moveTypeModule(AsmPrinter::CFI_M_None) {}
DwarfCFIException::~DwarfCFIException() {}
/// endModule - Emit all exception information that should come after the
/// content.
void DwarfCFIException::endModule() {
if (moveTypeModule == AsmPrinter::CFI_M_Debug)
Asm->OutStreamer.EmitCFISections(false, true);
// SjLj uses this pass and it doesn't need this info.
if (!Asm->MAI->usesCFIForEH())
return;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
unsigned PerEncoding = TLOF.getPersonalityEncoding();
if ((PerEncoding & 0x80) != dwarf::DW_EH_PE_indirect)
return;
// Emit references to all used personality functions
const std::vector<const Function*> &Personalities = MMI->getPersonalities();
for (size_t i = 0, e = Personalities.size(); i != e; ++i) {
if (!Personalities[i])
continue;
MCSymbol *Sym = Asm->getSymbol(Personalities[i]);
TLOF.emitPersonalityValue(Asm->OutStreamer, Asm->TM, Sym);
}
}
/// beginFunction - Gather pre-function exception information. Assumes it's
/// being emitted immediately after the function entry point.
void DwarfCFIException::beginFunction(const MachineFunction *MF) {
shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
// If any landing pads survive, we need an EH table.
bool hasLandingPads = !MMI->getLandingPads().empty();
// See if we need frame move info.
AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
if (MoveType == AsmPrinter::CFI_M_EH ||
(MoveType == AsmPrinter::CFI_M_Debug &&
moveTypeModule == AsmPrinter::CFI_M_None))
moveTypeModule = MoveType;
shouldEmitMoves = MoveType != AsmPrinter::CFI_M_None;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
unsigned PerEncoding = TLOF.getPersonalityEncoding();
const Function *Per = MMI->getPersonality();
shouldEmitPersonality = hasLandingPads &&
PerEncoding != dwarf::DW_EH_PE_omit && Per;
unsigned LSDAEncoding = TLOF.getLSDAEncoding();
shouldEmitLSDA = shouldEmitPersonality &&
LSDAEncoding != dwarf::DW_EH_PE_omit;
if (!shouldEmitPersonality && !shouldEmitMoves)
return;
Asm->OutStreamer.EmitCFIStartProc(/*IsSimple=*/false);
// Indicate personality routine, if any.
if (!shouldEmitPersonality)
return;
const MCSymbol *Sym =
TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
MCSymbol *EHBegin =
Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
if (Asm->MAI->useAssignmentForEHBegin()) {
MCContext &Ctx = Asm->OutContext;
MCSymbol *CurPos = Ctx.CreateTempSymbol();
Asm->OutStreamer.EmitLabel(CurPos);
Asm->OutStreamer.EmitAssignment(EHBegin,
MCSymbolRefExpr::Create(CurPos, Ctx));
} else {
Asm->OutStreamer.EmitLabel(EHBegin);
}
// Provide LSDA information.
if (!shouldEmitLSDA)
return;
Asm->OutStreamer.EmitCFILsda(Asm->GetTempSymbol("exception",
Asm->getFunctionNumber()),
LSDAEncoding);
}
/// endFunction - Gather and emit post-function exception information.
///
void DwarfCFIException::endFunction(const MachineFunction *) {
if (!shouldEmitPersonality && !shouldEmitMoves)
return;
Asm->OutStreamer.EmitCFIEndProc();
if (!shouldEmitPersonality)
return;
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
Asm->getFunctionNumber()));
// Map all labels and get rid of any dead landing pads.
MMI->TidyLandingPads();
emitExceptionTable();
}
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