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 ARMException(AsmPrinter * A)22ARMException::ARMException(AsmPrinter *A) : EHStreamer(A) {} 23 24 ARMException::~ARMException() = default; 25 getTargetStreamer()26ARMTargetStreamer &ARMException::getTargetStreamer() { 27 MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer(); 28 return static_cast<ARMTargetStreamer &>(TS); 29 } 30 beginFunction(const MachineFunction * MF)31void 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 markFunctionEnd()51void ARMException::markFunctionEnd() { 52 if (shouldEmitCFI) 53 Asm->OutStreamer->emitCFIEndProc(); 54 } 55 56 /// endFunction - Gather and emit post-function exception information. 57 /// endFunction(const MachineFunction * MF)58void ARMException::endFunction(const MachineFunction *MF) { 59 ARMTargetStreamer &ATS = getTargetStreamer(); 60 const Function &F = MF->getFunction(); 61 const Function *Per = nullptr; 62 if (F.hasPersonalityFn()) 63 Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()); 64 bool forceEmitPersonality = 65 F.hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) && 66 F.needsUnwindTableEntry(); 67 bool shouldEmitPersonality = forceEmitPersonality || 68 !MF->getLandingPads().empty(); 69 if (!Asm->MF->getFunction().needsUnwindTableEntry() && 70 !shouldEmitPersonality) 71 ATS.emitCantUnwind(); 72 else if (shouldEmitPersonality) { 73 // Emit references to personality. 74 if (Per) { 75 MCSymbol *PerSym = Asm->getSymbol(Per); 76 ATS.emitPersonality(PerSym); 77 } 78 79 // Emit .handlerdata directive. 80 ATS.emitHandlerData(); 81 82 // Emit actual exception table 83 emitExceptionTable(); 84 } 85 86 if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM) 87 ATS.emitFnEnd(); 88 } 89 emitTypeInfos(unsigned TTypeEncoding,MCSymbol * TTBaseLabel)90void ARMException::emitTypeInfos(unsigned TTypeEncoding, 91 MCSymbol *TTBaseLabel) { 92 const MachineFunction *MF = Asm->MF; 93 const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos(); 94 const std::vector<unsigned> &FilterIds = MF->getFilterIds(); 95 96 bool VerboseAsm = Asm->OutStreamer->isVerboseAsm(); 97 98 int Entry = 0; 99 // Emit the Catch TypeInfos. 100 if (VerboseAsm && !TypeInfos.empty()) { 101 Asm->OutStreamer->AddComment(">> Catch TypeInfos <<"); 102 Asm->OutStreamer->addBlankLine(); 103 Entry = TypeInfos.size(); 104 } 105 106 for (const GlobalValue *GV : reverse(TypeInfos)) { 107 if (VerboseAsm) 108 Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--)); 109 Asm->emitTTypeReference(GV, TTypeEncoding); 110 } 111 112 Asm->OutStreamer->emitLabel(TTBaseLabel); 113 114 // Emit the Exception Specifications. 115 if (VerboseAsm && !FilterIds.empty()) { 116 Asm->OutStreamer->AddComment(">> Filter TypeInfos <<"); 117 Asm->OutStreamer->addBlankLine(); 118 Entry = 0; 119 } 120 for (std::vector<unsigned>::const_iterator 121 I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) { 122 unsigned TypeID = *I; 123 if (VerboseAsm) { 124 --Entry; 125 if (TypeID != 0) 126 Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry)); 127 } 128 129 Asm->emitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]), 130 TTypeEncoding); 131 } 132 } 133