text: //===-- CodeGen/AsmPrinter/AIXException.cpp - AIX Exception Impl ----------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  // This file contains support for writing AIX exception info into asm files.
  //
  //===----------------------------------------------------------------------===//
  
  #include "DwarfException.h"
  #include "llvm/CodeGen/AsmPrinter.h"
  #include "llvm/CodeGen/MachineModuleInfo.h"
  #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
  #include "llvm/MC/MCSectionXCOFF.h"
  #include "llvm/MC/MCStreamer.h"
  #include "llvm/Target/TargetLoweringObjectFile.h"
  #include "llvm/Target/TargetMachine.h"
  
  namespace llvm {
  
  AIXException::AIXException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {}
  
  void AIXException::emitExceptionInfoTable(const MCSymbol *LSDA,
                                            const MCSymbol *PerSym) {
    // Generate EH Info Table.
    // The EH Info Table, aka, 'compat unwind section' on AIX, have the following
    // format: struct eh_info_t {
    //   unsigned version;           /* EH info verion 0 */
    // #if defined(__64BIT__)
    //   char _pad[4];               /* padding */
    // #endif
    //   unsigned long lsda;         /* Pointer to LSDA */
    //   unsigned long personality;  /* Pointer to the personality routine */
    //   }
  
    Asm->OutStreamer->SwitchSection(
        Asm->getObjFileLowering().getCompactUnwindSection());
    MCSymbol *EHInfoLabel =
        TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(Asm->MF);
    Asm->OutStreamer->emitLabel(EHInfoLabel);
  
    // Version number.
    Asm->emitInt32(0);
  
    const DataLayout &DL = MMI->getModule()->getDataLayout();
    const unsigned PointerSize = DL.getPointerSize();
  
    // Add necessary paddings in 64 bit mode.
    Asm->OutStreamer->emitValueToAlignment(PointerSize);
  
    // LSDA location.
    Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(LSDA, Asm->OutContext),
                                PointerSize);
  
    // Personality routine.
    Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(PerSym, Asm->OutContext),
                                PointerSize);
  }
  
  void AIXException::endFunction(const MachineFunction *MF) {
    if (!TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock(MF))
      return;
  
    const MCSymbol *LSDALabel = emitExceptionTable();
  
    const Function &F = MF->getFunction();
    assert(F.hasPersonalityFn() &&
           "Landingpads are presented, but no personality routine is found.");
    const GlobalValue *Per =
        dyn_cast<GlobalValue>(F.getPersonalityFn()->stripPointerCasts());
    const MCSymbol *PerSym = Asm->TM.getSymbol(Per);
  
    emitExceptionInfoTable(LSDALabel, PerSym);
  }
  
  } // End of namespace llvm
  