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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/Module.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineLocation.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/Target/Mangler.h"
#include "llvm/Target/TargetData.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"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
using namespace llvm;
DwarfCFIException::DwarfCFIException(AsmPrinter *A)
: DwarfException(A),
shouldEmitTable(false), shouldEmitMoves(false), shouldEmitTableModule(false)
{}
DwarfCFIException::~DwarfCFIException() {}
/// EndModule - Emit all exception information that should come after the
/// content.
void DwarfCFIException::EndModule() {
if (!Asm->MAI->isExceptionHandlingDwarf())
return;
if (!shouldEmitTableModule)
return;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
unsigned PerEncoding = TLOF.getPersonalityEncoding();
// Begin eh frame section.
Asm->OutStreamer.SwitchSection(TLOF.getEHFrameSection());
// 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) {
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("personality", i));
Asm->EmitReference(Personalities[i], PerEncoding);
}
}
/// BeginFunction - Gather pre-function exception information. Assumes it's
/// being emitted immediately after the function entry point.
void DwarfCFIException::BeginFunction(const MachineFunction *MF) {
shouldEmitTable = shouldEmitMoves = false;
// If any landing pads survive, we need an EH table.
shouldEmitTable = !MMI->getLandingPads().empty();
// See if we need frame move info.
shouldEmitMoves =
!Asm->MF->getFunction()->doesNotThrow() || UnwindTablesMandatory;
if (shouldEmitMoves || shouldEmitTable)
// Assumes in correct section after the entry point.
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
Asm->getFunctionNumber()));
shouldEmitTableModule |= shouldEmitTable;
if (shouldEmitMoves) {
const TargetFrameLowering *TFL = Asm->TM.getFrameLowering();
Asm->OutStreamer.EmitCFIStartProc();
// Indicate locations of general callee saved registers in frame.
std::vector<MachineMove> Moves;
TFL->getInitialFrameState(Moves);
Asm->EmitCFIFrameMoves(Moves);
Asm->EmitCFIFrameMoves(MMI->getFrameMoves());
}
if (!shouldEmitTable)
return;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
// Provide LSDA information.
unsigned LSDAEncoding = TLOF.getLSDAEncoding();
if (LSDAEncoding != dwarf::DW_EH_PE_omit)
Asm->OutStreamer.EmitCFILsda(Asm->GetTempSymbol("exception",
Asm->getFunctionNumber()),
LSDAEncoding);
// Indicate personality routine, if any.
unsigned PerEncoding = TLOF.getPersonalityEncoding();
if (PerEncoding != dwarf::DW_EH_PE_omit &&
MMI->getPersonalities()[MMI->getPersonalityIndex()])
Asm->OutStreamer.EmitCFIPersonality(Asm->GetTempSymbol("personality",
MMI->getPersonalityIndex()),
PerEncoding);
}
/// EndFunction - Gather and emit post-function exception information.
///
void DwarfCFIException::EndFunction() {
if (!shouldEmitMoves && !shouldEmitTable) return;
if (shouldEmitMoves)
Asm->OutStreamer.EmitCFIEndProc();
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
Asm->getFunctionNumber()));
// Map all labels and get rid of any dead landing pads.
MMI->TidyLandingPads();
if (shouldEmitTable)
EmitExceptionTable();
}
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