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/DataLayout.h" 18 #include "llvm/IR/Mangler.h" 19 #include "llvm/IR/Module.h" 20 #include "llvm/MC/MCAsmInfo.h" 21 #include "llvm/MC/MCExpr.h" 22 #include "llvm/MC/MCSection.h" 23 #include "llvm/MC/MCStreamer.h" 24 #include "llvm/MC/MCSymbol.h" 25 #include "llvm/Support/FormattedStream.h" 26 #include "llvm/Target/TargetOptions.h" 27 using namespace llvm; 28 29 ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {} 30 31 ARMException::~ARMException() {} 32 33 ARMTargetStreamer &ARMException::getTargetStreamer() { 34 MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer(); 35 return static_cast<ARMTargetStreamer &>(TS); 36 } 37 38 void ARMException::beginFunction(const MachineFunction *MF) { 39 if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM) 40 getTargetStreamer().emitFnStart(); 41 // See if we need call frame info. 42 AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves(); 43 assert(MoveType != AsmPrinter::CFI_M_EH && 44 "non-EH CFI not yet supported in prologue with EHABI lowering"); 45 46 if (MoveType == AsmPrinter::CFI_M_Debug) { 47 if (!hasEmittedCFISections) { 48 if (Asm->needsOnlyDebugCFIMoves()) 49 Asm->OutStreamer->EmitCFISections(false, true); 50 hasEmittedCFISections = true; 51 } 52 53 shouldEmitCFI = true; 54 Asm->OutStreamer->EmitCFIStartProc(false); 55 } 56 } 57 58 /// endFunction - Gather and emit post-function exception information. 59 /// 60 void ARMException::endFunction(const MachineFunction *MF) { 61 ARMTargetStreamer &ATS = getTargetStreamer(); 62 const Function &F = MF->getFunction(); 63 const Function *Per = nullptr; 64 if (F.hasPersonalityFn()) 65 Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()); 66 bool forceEmitPersonality = 67 F.hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) && 68 F.needsUnwindTableEntry(); 69 bool shouldEmitPersonality = forceEmitPersonality || 70 !MF->getLandingPads().empty(); 71 if (!Asm->MF->getFunction().needsUnwindTableEntry() && 72 !shouldEmitPersonality) 73 ATS.emitCantUnwind(); 74 else if (shouldEmitPersonality) { 75 // Emit references to personality. 76 if (Per) { 77 MCSymbol *PerSym = Asm->getSymbol(Per); 78 Asm->OutStreamer->EmitSymbolAttribute(PerSym, MCSA_Global); 79 ATS.emitPersonality(PerSym); 80 } 81 82 // Emit .handlerdata directive. 83 ATS.emitHandlerData(); 84 85 // Emit actual exception table 86 emitExceptionTable(); 87 } 88 89 if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM) 90 ATS.emitFnEnd(); 91 } 92 93 void ARMException::emitTypeInfos(unsigned TTypeEncoding, 94 MCSymbol *TTBaseLabel) { 95 const MachineFunction *MF = Asm->MF; 96 const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos(); 97 const std::vector<unsigned> &FilterIds = MF->getFilterIds(); 98 99 bool VerboseAsm = Asm->OutStreamer->isVerboseAsm(); 100 101 int Entry = 0; 102 // Emit the Catch TypeInfos. 103 if (VerboseAsm && !TypeInfos.empty()) { 104 Asm->OutStreamer->AddComment(">> Catch TypeInfos <<"); 105 Asm->OutStreamer->AddBlankLine(); 106 Entry = TypeInfos.size(); 107 } 108 109 for (const GlobalValue *GV : reverse(TypeInfos)) { 110 if (VerboseAsm) 111 Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--)); 112 Asm->EmitTTypeReference(GV, TTypeEncoding); 113 } 114 115 Asm->OutStreamer->EmitLabel(TTBaseLabel); 116 117 // Emit the Exception Specifications. 118 if (VerboseAsm && !FilterIds.empty()) { 119 Asm->OutStreamer->AddComment(">> Filter TypeInfos <<"); 120 Asm->OutStreamer->AddBlankLine(); 121 Entry = 0; 122 } 123 for (std::vector<unsigned>::const_iterator 124 I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) { 125 unsigned TypeID = *I; 126 if (VerboseAsm) { 127 --Entry; 128 if (TypeID != 0) 129 Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry)); 130 } 131 132 Asm->EmitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]), 133 TTypeEncoding); 134 } 135 } 136