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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/DataLayout.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/Module.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/Mangler.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)
: DwarfException(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);
if (!Asm->MAI->isExceptionHandlingDwarf())
return;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
unsigned PerEncoding = TLOF.getPersonalityEncoding();
if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel)
return;
// Emit references to all used personality functions
bool AtLeastOne = false;
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->Mang->getSymbol(Personalities[i]);
TLOF.emitPersonalityValue(Asm->OutStreamer, Asm->TM, Sym);
AtLeastOne = true;
}
if (AtLeastOne && !TLOF.isFunctionEHFrameSymbolPrivate()) {
// This is a temporary hack to keep sections in the same order they
// were before. This lets us produce bit identical outputs while
// transitioning to CFI.
Asm->OutStreamer.SwitchSection(
const_cast<TargetLoweringObjectFile&>(TLOF).getEHFrameSection());
}
}
/// 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->getPersonalities()[MMI->getPersonalityIndex()];
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();
// Indicate personality routine, if any.
if (!shouldEmitPersonality)
return;
const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang, MMI);
Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
Asm->OutStreamer.EmitDebugLabel
(Asm->GetTempSymbol("eh_func_begin",
Asm->getFunctionNumber()));
// 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() {
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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