93 lines · cpp
1//===-- CodeGen/AsmPrinter/AIXException.cpp - AIX Exception Impl ----------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file contains support for writing AIX exception info into asm files.10//11//===----------------------------------------------------------------------===//12 13#include "DwarfException.h"14#include "llvm/CodeGen/AsmPrinter.h"15#include "llvm/CodeGen/MachineModuleInfo.h"16#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"17#include "llvm/IR/Module.h"18#include "llvm/MC/MCSectionXCOFF.h"19#include "llvm/MC/MCStreamer.h"20#include "llvm/Target/TargetLoweringObjectFile.h"21#include "llvm/Target/TargetMachine.h"22 23using namespace llvm;24 25AIXException::AIXException(AsmPrinter *A) : EHStreamer(A) {}26 27void AIXException::emitExceptionInfoTable(const MCSymbol *LSDA,28 const MCSymbol *PerSym) {29 // Generate EH Info Table.30 // The EH Info Table, aka, 'compat unwind section' on AIX, have the following31 // format: struct eh_info_t {32 // unsigned version; /* EH info verion 0 */33 // #if defined(__64BIT__)34 // char _pad[4]; /* padding */35 // #endif36 // unsigned long lsda; /* Pointer to LSDA */37 // unsigned long personality; /* Pointer to the personality routine */38 // }39 40 auto *EHInfo = static_cast<MCSectionXCOFF *>(41 Asm->getObjFileLowering().getCompactUnwindSection());42 if (Asm->TM.getFunctionSections()) {43 // If option -ffunction-sections is on, append the function name to the44 // name of EH Info Table csect so that each function has its own EH Info45 // Table csect. This helps the linker to garbage-collect EH info of unused46 // functions.47 SmallString<128> NameStr = EHInfo->getName();48 raw_svector_ostream(NameStr) << '.' << Asm->MF->getFunction().getName();49 EHInfo = Asm->OutContext.getXCOFFSection(NameStr, EHInfo->getKind(),50 EHInfo->getCsectProp());51 }52 Asm->OutStreamer->switchSection(EHInfo);53 MCSymbol *EHInfoLabel =54 TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(Asm->MF);55 Asm->OutStreamer->emitLabel(EHInfoLabel);56 57 // Version number.58 Asm->emitInt32(0);59 60 const DataLayout &DL = MMI->getModule()->getDataLayout();61 const unsigned PointerSize = DL.getPointerSize();62 63 // Add necessary paddings in 64 bit mode.64 Asm->OutStreamer->emitValueToAlignment(Align(PointerSize));65 66 // LSDA location.67 Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(LSDA, Asm->OutContext),68 PointerSize);69 70 // Personality routine.71 Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(PerSym, Asm->OutContext),72 PointerSize);73}74 75void AIXException::endFunction(const MachineFunction *MF) {76 // There is no easy way to access register information in `AIXException`77 // class. when ShouldEmitEHBlock is false and VRs are saved, A dumy eh info78 // table are emitted in PPCAIXAsmPrinter::emitFunctionBodyEnd.79 if (!TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock(MF))80 return;81 82 const MCSymbol *LSDALabel = emitExceptionTable();83 84 const Function &F = MF->getFunction();85 assert(F.hasPersonalityFn() &&86 "Landingpads are presented, but no personality routine is found.");87 const auto *Per =88 cast<GlobalValue>(F.getPersonalityFn()->stripPointerCasts());89 const MCSymbol *PerSym = Asm->TM.getSymbol(Per);90 91 emitExceptionInfoTable(LSDALabel, PerSym);92}93