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-exception 6 // 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/MC/MCSectionXCOFF.h" 18 #include "llvm/MC/MCStreamer.h" 19 #include "llvm/Target/TargetLoweringObjectFile.h" 20 #include "llvm/Target/TargetMachine.h" 21 22 namespace llvm { 23 24 AIXException::AIXException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {} 25 26 void AIXException::emitExceptionInfoTable(const MCSymbol *LSDA, 27 const MCSymbol *PerSym) { 28 // Generate EH Info Table. 29 // The EH Info Table, aka, 'compat unwind section' on AIX, have the following 30 // format: struct eh_info_t { 31 // unsigned version; /* EH info verion 0 */ 32 // #if defined(__64BIT__) 33 // char _pad[4]; /* padding */ 34 // #endif 35 // unsigned long lsda; /* Pointer to LSDA */ 36 // unsigned long personality; /* Pointer to the personality routine */ 37 // } 38 39 Asm->OutStreamer->SwitchSection( 40 Asm->getObjFileLowering().getCompactUnwindSection()); 41 MCSymbol *EHInfoLabel = 42 TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(Asm->MF); 43 Asm->OutStreamer->emitLabel(EHInfoLabel); 44 45 // Version number. 46 Asm->emitInt32(0); 47 48 const DataLayout &DL = MMI->getModule()->getDataLayout(); 49 const unsigned PointerSize = DL.getPointerSize(); 50 51 // Add necessary paddings in 64 bit mode. 52 Asm->OutStreamer->emitValueToAlignment(PointerSize); 53 54 // LSDA location. 55 Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(LSDA, Asm->OutContext), 56 PointerSize); 57 58 // Personality routine. 59 Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(PerSym, Asm->OutContext), 60 PointerSize); 61 } 62 63 void AIXException::endFunction(const MachineFunction *MF) { 64 if (!TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock(MF)) 65 return; 66 67 const MCSymbol *LSDALabel = emitExceptionTable(); 68 69 const Function &F = MF->getFunction(); 70 assert(F.hasPersonalityFn() && 71 "Landingpads are presented, but no personality routine is found."); 72 const Function *Per = 73 dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()); 74 const MCSymbol *PerSym = Asm->TM.getSymbol(Per); 75 76 emitExceptionInfoTable(LSDALabel, PerSym); 77 } 78 79 } // End of namespace llvm 80