1 //===-- CodeGen/AsmPrinter/ARMException.cpp - ARM EHABI 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 DWARF exception info into asm files. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "DwarfException.h" 14 #include "llvm/ADT/Twine.h" 15 #include "llvm/CodeGen/AsmPrinter.h" 16 #include "llvm/CodeGen/MachineFunction.h" 17 #include "llvm/IR/Function.h" 18 #include "llvm/MC/MCAsmInfo.h" 19 #include "llvm/MC/MCStreamer.h" 20 using namespace llvm; 21 22 ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {} 23 24 ARMException::~ARMException() = default; 25 26 ARMTargetStreamer &ARMException::getTargetStreamer() { 27 MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer(); 28 return static_cast<ARMTargetStreamer &>(TS); 29 } 30 31 void ARMException::beginFunction(const MachineFunction *MF) { 32 if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM) 33 getTargetStreamer().emitFnStart(); 34 // See if we need call frame info. 35 AsmPrinter::CFISection CFISecType = Asm->getFunctionCFISectionType(*MF); 36 assert(CFISecType != AsmPrinter::CFISection::EH && 37 "non-EH CFI not yet supported in prologue with EHABI lowering"); 38 39 if (CFISecType == AsmPrinter::CFISection::Debug) { 40 if (!hasEmittedCFISections) { 41 if (Asm->getModuleCFISectionType() == AsmPrinter::CFISection::Debug) 42 Asm->OutStreamer->emitCFISections(false, true); 43 hasEmittedCFISections = true; 44 } 45 46 shouldEmitCFI = true; 47 Asm->OutStreamer->emitCFIStartProc(false); 48 } 49 } 50 51 /// endFunction - Gather and emit post-function exception information. 52 /// 53 void ARMException::endFunction(const MachineFunction *MF) { 54 ARMTargetStreamer &ATS = getTargetStreamer(); 55 const Function &F = MF->getFunction(); 56 const Function *Per = nullptr; 57 if (F.hasPersonalityFn()) 58 Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()); 59 bool forceEmitPersonality = 60 F.hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) && 61 F.needsUnwindTableEntry(); 62 bool shouldEmitPersonality = forceEmitPersonality || 63 !MF->getLandingPads().empty(); 64 if (!Asm->MF->getFunction().needsUnwindTableEntry() && 65 !shouldEmitPersonality) 66 ATS.emitCantUnwind(); 67 else if (shouldEmitPersonality) { 68 // Emit references to personality. 69 if (Per) { 70 MCSymbol *PerSym = Asm->getSymbol(Per); 71 ATS.emitPersonality(PerSym); 72 } 73 74 // Emit .handlerdata directive. 75 ATS.emitHandlerData(); 76 77 // Emit actual exception table 78 emitExceptionTable(); 79 } 80 81 if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM) 82 ATS.emitFnEnd(); 83 } 84 85 void ARMException::emitTypeInfos(unsigned TTypeEncoding, 86 MCSymbol *TTBaseLabel) { 87 const MachineFunction *MF = Asm->MF; 88 const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos(); 89 const std::vector<unsigned> &FilterIds = MF->getFilterIds(); 90 91 bool VerboseAsm = Asm->OutStreamer->isVerboseAsm(); 92 93 int Entry = 0; 94 // Emit the Catch TypeInfos. 95 if (VerboseAsm && !TypeInfos.empty()) { 96 Asm->OutStreamer->AddComment(">> Catch TypeInfos <<"); 97 Asm->OutStreamer->addBlankLine(); 98 Entry = TypeInfos.size(); 99 } 100 101 for (const GlobalValue *GV : reverse(TypeInfos)) { 102 if (VerboseAsm) 103 Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--)); 104 Asm->emitTTypeReference(GV, TTypeEncoding); 105 } 106 107 Asm->OutStreamer->emitLabel(TTBaseLabel); 108 109 // Emit the Exception Specifications. 110 if (VerboseAsm && !FilterIds.empty()) { 111 Asm->OutStreamer->AddComment(">> Filter TypeInfos <<"); 112 Asm->OutStreamer->addBlankLine(); 113 Entry = 0; 114 } 115 for (std::vector<unsigned>::const_iterator 116 I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) { 117 unsigned TypeID = *I; 118 if (VerboseAsm) { 119 --Entry; 120 if (TypeID != 0) 121 Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry)); 122 } 123 124 Asm->emitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]), 125 TTypeEncoding); 126 } 127 } 128