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//===-- 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 Function *Per = 
      dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()); 
  const MCSymbol *PerSym = Asm->TM.getSymbol(Per); 
 
  emitExceptionInfoTable(LSDALabel, PerSym); 
} 
 
} // End of namespace llvm