1 //===- EHPersonalities.cpp - Compute EH-related information ---------------===// 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 #include "llvm/IR/EHPersonalities.h" 10 #include "llvm/ADT/StringSwitch.h" 11 #include "llvm/IR/CFG.h" 12 #include "llvm/IR/Constants.h" 13 #include "llvm/IR/Function.h" 14 #include "llvm/IR/Instructions.h" 15 #include "llvm/IR/Module.h" 16 #include "llvm/Support/Debug.h" 17 #include "llvm/Support/raw_ostream.h" 18 #include "llvm/TargetParser/Triple.h" 19 using namespace llvm; 20 21 /// See if the given exception handling personality function is one that we 22 /// understand. If so, return a description of it; otherwise return Unknown. 23 EHPersonality llvm::classifyEHPersonality(const Value *Pers) { 24 const GlobalValue *F = 25 Pers ? dyn_cast<GlobalValue>(Pers->stripPointerCasts()) : nullptr; 26 if (!F || !F->getValueType() || !F->getValueType()->isFunctionTy()) 27 return EHPersonality::Unknown; 28 return StringSwitch<EHPersonality>(F->getName()) 29 .Case("__gnat_eh_personality", EHPersonality::GNU_Ada) 30 .Case("__gxx_personality_v0", EHPersonality::GNU_CXX) 31 .Case("__gxx_personality_seh0", EHPersonality::GNU_CXX) 32 .Case("__gxx_personality_sj0", EHPersonality::GNU_CXX_SjLj) 33 .Case("__gcc_personality_v0", EHPersonality::GNU_C) 34 .Case("__gcc_personality_seh0", EHPersonality::GNU_C) 35 .Case("__gcc_personality_sj0", EHPersonality::GNU_C_SjLj) 36 .Case("__objc_personality_v0", EHPersonality::GNU_ObjC) 37 .Case("_except_handler3", EHPersonality::MSVC_X86SEH) 38 .Case("_except_handler4", EHPersonality::MSVC_X86SEH) 39 .Case("__C_specific_handler", EHPersonality::MSVC_TableSEH) 40 .Case("__CxxFrameHandler3", EHPersonality::MSVC_CXX) 41 .Case("ProcessCLRException", EHPersonality::CoreCLR) 42 .Case("rust_eh_personality", EHPersonality::Rust) 43 .Case("__gxx_wasm_personality_v0", EHPersonality::Wasm_CXX) 44 .Case("__xlcxx_personality_v1", EHPersonality::XL_CXX) 45 .Default(EHPersonality::Unknown); 46 } 47 48 StringRef llvm::getEHPersonalityName(EHPersonality Pers) { 49 switch (Pers) { 50 case EHPersonality::GNU_Ada: 51 return "__gnat_eh_personality"; 52 case EHPersonality::GNU_CXX: 53 return "__gxx_personality_v0"; 54 case EHPersonality::GNU_CXX_SjLj: 55 return "__gxx_personality_sj0"; 56 case EHPersonality::GNU_C: 57 return "__gcc_personality_v0"; 58 case EHPersonality::GNU_C_SjLj: 59 return "__gcc_personality_sj0"; 60 case EHPersonality::GNU_ObjC: 61 return "__objc_personality_v0"; 62 case EHPersonality::MSVC_X86SEH: 63 return "_except_handler3"; 64 case EHPersonality::MSVC_TableSEH: 65 return "__C_specific_handler"; 66 case EHPersonality::MSVC_CXX: 67 return "__CxxFrameHandler3"; 68 case EHPersonality::CoreCLR: 69 return "ProcessCLRException"; 70 case EHPersonality::Rust: 71 return "rust_eh_personality"; 72 case EHPersonality::Wasm_CXX: 73 return "__gxx_wasm_personality_v0"; 74 case EHPersonality::XL_CXX: 75 return "__xlcxx_personality_v1"; 76 case EHPersonality::Unknown: 77 llvm_unreachable("Unknown EHPersonality!"); 78 } 79 80 llvm_unreachable("Invalid EHPersonality!"); 81 } 82 83 EHPersonality llvm::getDefaultEHPersonality(const Triple &T) { 84 if (T.isPS5()) 85 return EHPersonality::GNU_CXX; 86 else 87 return EHPersonality::GNU_C; 88 } 89 90 bool llvm::canSimplifyInvokeNoUnwind(const Function *F) { 91 EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn()); 92 // We can't simplify any invokes to nounwind functions if the personality 93 // function wants to catch asynch exceptions. The nounwind attribute only 94 // implies that the function does not throw synchronous exceptions. 95 96 // Cannot simplify CXX Personality under AsynchEH 97 const llvm::Module *M = (const llvm::Module *)F->getParent(); 98 bool EHa = M->getModuleFlag("eh-asynch"); 99 return !EHa && !isAsynchronousEHPersonality(Personality); 100 } 101 102 DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) { 103 SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist; 104 BasicBlock *EntryBlock = &F.getEntryBlock(); 105 DenseMap<BasicBlock *, ColorVector> BlockColors; 106 107 // Build up the color map, which maps each block to its set of 'colors'. 108 // For any block B the "colors" of B are the set of funclets F (possibly 109 // including a root "funclet" representing the main function) such that 110 // F will need to directly contain B or a copy of B (where the term "directly 111 // contain" is used to distinguish from being "transitively contained" in 112 // a nested funclet). 113 // 114 // Note: Despite not being a funclet in the truest sense, a catchswitch is 115 // considered to belong to its own funclet for the purposes of coloring. 116 117 DEBUG_WITH_TYPE("winehprepare-coloring", 118 dbgs() << "\nColoring funclets for " << F.getName() << "\n"); 119 120 Worklist.push_back({EntryBlock, EntryBlock}); 121 122 while (!Worklist.empty()) { 123 BasicBlock *Visiting; 124 BasicBlock *Color; 125 std::tie(Visiting, Color) = Worklist.pop_back_val(); 126 DEBUG_WITH_TYPE("winehprepare-coloring", 127 dbgs() << "Visiting " << Visiting->getName() << ", " 128 << Color->getName() << "\n"); 129 Instruction *VisitingHead = Visiting->getFirstNonPHI(); 130 if (VisitingHead->isEHPad()) { 131 // Mark this funclet head as a member of itself. 132 Color = Visiting; 133 } 134 // Note that this is a member of the given color. 135 ColorVector &Colors = BlockColors[Visiting]; 136 if (!is_contained(Colors, Color)) 137 Colors.push_back(Color); 138 else 139 continue; 140 141 DEBUG_WITH_TYPE("winehprepare-coloring", 142 dbgs() << " Assigned color \'" << Color->getName() 143 << "\' to block \'" << Visiting->getName() 144 << "\'.\n"); 145 146 BasicBlock *SuccColor = Color; 147 Instruction *Terminator = Visiting->getTerminator(); 148 if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) { 149 Value *ParentPad = CatchRet->getCatchSwitchParentPad(); 150 if (isa<ConstantTokenNone>(ParentPad)) 151 SuccColor = EntryBlock; 152 else 153 SuccColor = cast<Instruction>(ParentPad)->getParent(); 154 } 155 156 for (BasicBlock *Succ : successors(Visiting)) 157 Worklist.push_back({Succ, SuccColor}); 158 } 159 return BlockColors; 160 } 161