forked from OSchip/llvm-project
165 lines
5.4 KiB
C++
165 lines
5.4 KiB
C++
//===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
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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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//
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// This file contains support for writing DWARF exception info into asm files.
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//
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//===----------------------------------------------------------------------===//
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#include "DwarfException.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Mangler.h"
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#include "llvm/IR/Module.h"
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#include "llvm/MC/MCAsmInfo.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/MCSection.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/MC/MachineLocation.h"
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#include "llvm/Support/Dwarf.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/FormattedStream.h"
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#include "llvm/Target/TargetFrameLowering.h"
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#include "llvm/Target/TargetLoweringObjectFile.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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using namespace llvm;
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DwarfCFIExceptionBase::DwarfCFIExceptionBase(AsmPrinter *A)
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: EHStreamer(A), shouldEmitCFI(false) {}
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void DwarfCFIExceptionBase::markFunctionEnd() {
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if (shouldEmitCFI)
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Asm->OutStreamer->EmitCFIEndProc();
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if (MMI->getLandingPads().empty())
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return;
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// Map all labels and get rid of any dead landing pads.
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MMI->TidyLandingPads();
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}
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DwarfCFIException::DwarfCFIException(AsmPrinter *A)
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: DwarfCFIExceptionBase(A), shouldEmitPersonality(false),
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shouldEmitLSDA(false), shouldEmitMoves(false),
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moveTypeModule(AsmPrinter::CFI_M_None) {}
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DwarfCFIException::~DwarfCFIException() {}
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/// endModule - Emit all exception information that should come after the
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/// content.
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void DwarfCFIException::endModule() {
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if (moveTypeModule == AsmPrinter::CFI_M_Debug)
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Asm->OutStreamer->EmitCFISections(false, true);
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// SjLj uses this pass and it doesn't need this info.
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if (!Asm->MAI->usesCFIForEH())
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return;
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const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
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unsigned PerEncoding = TLOF.getPersonalityEncoding();
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if ((PerEncoding & 0x80) != dwarf::DW_EH_PE_indirect)
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return;
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// Emit references to all used personality functions
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const std::vector<const Function*> &Personalities = MMI->getPersonalities();
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for (size_t i = 0, e = Personalities.size(); i != e; ++i) {
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if (!Personalities[i])
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continue;
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MCSymbol *Sym = Asm->getSymbol(Personalities[i]);
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TLOF.emitPersonalityValue(*Asm->OutStreamer, Asm->getDataLayout(), Sym);
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}
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}
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void DwarfCFIException::beginFunction(const MachineFunction *MF) {
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shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
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const Function *F = MF->getFunction();
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// If any landing pads survive, we need an EH table.
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bool hasLandingPads = !MMI->getLandingPads().empty();
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// See if we need frame move info.
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AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
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if (MoveType == AsmPrinter::CFI_M_EH ||
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(MoveType == AsmPrinter::CFI_M_Debug &&
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moveTypeModule == AsmPrinter::CFI_M_None))
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moveTypeModule = MoveType;
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shouldEmitMoves = MoveType != AsmPrinter::CFI_M_None;
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const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
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unsigned PerEncoding = TLOF.getPersonalityEncoding();
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const Function *Per = nullptr;
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if (F->hasPersonalityFn())
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Per = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
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assert(!MMI->getPersonality() || Per == MMI->getPersonality());
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// Emit a personality function even when there are no landing pads
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bool forceEmitPersonality =
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// ...if a personality function is explicitly specified
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F->hasPersonalityFn() &&
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// ... and it's not known to be a noop in the absence of invokes
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!isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
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// ... and we're not explicitly asked not to emit it
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F->needsUnwindTableEntry();
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shouldEmitPersonality =
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(forceEmitPersonality ||
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(hasLandingPads && PerEncoding != dwarf::DW_EH_PE_omit)) &&
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Per;
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unsigned LSDAEncoding = TLOF.getLSDAEncoding();
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shouldEmitLSDA = shouldEmitPersonality &&
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LSDAEncoding != dwarf::DW_EH_PE_omit;
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shouldEmitCFI = shouldEmitPersonality || shouldEmitMoves;
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if (!shouldEmitCFI)
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return;
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Asm->OutStreamer->EmitCFIStartProc(/*IsSimple=*/false);
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// Indicate personality routine, if any.
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if (!shouldEmitPersonality)
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return;
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// If we are forced to emit this personality, make sure to record
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// it because it might not appear in any landingpad
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if (forceEmitPersonality)
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MMI->addPersonality(Per);
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const MCSymbol *Sym =
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TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
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Asm->OutStreamer->EmitCFIPersonality(Sym, PerEncoding);
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// Provide LSDA information.
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if (!shouldEmitLSDA)
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return;
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Asm->OutStreamer->EmitCFILsda(Asm->getCurExceptionSym(), LSDAEncoding);
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}
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/// endFunction - Gather and emit post-function exception information.
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///
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void DwarfCFIException::endFunction(const MachineFunction *) {
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if (!shouldEmitPersonality)
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return;
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emitExceptionTable();
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}
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