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 .Case("__zos_cxx_personality_v2", EHPersonality::ZOS_CXX) 46 .Default(EHPersonality::Unknown); 47 } 48 49 StringRef llvm::getEHPersonalityName(EHPersonality Pers) { 50 switch (Pers) { 51 case EHPersonality::GNU_Ada: 52 return "__gnat_eh_personality"; 53 case EHPersonality::GNU_CXX: 54 return "__gxx_personality_v0"; 55 case EHPersonality::GNU_CXX_SjLj: 56 return "__gxx_personality_sj0"; 57 case EHPersonality::GNU_C: 58 return "__gcc_personality_v0"; 59 case EHPersonality::GNU_C_SjLj: 60 return "__gcc_personality_sj0"; 61 case EHPersonality::GNU_ObjC: 62 return "__objc_personality_v0"; 63 case EHPersonality::MSVC_X86SEH: 64 return "_except_handler3"; 65 case EHPersonality::MSVC_TableSEH: 66 return "__C_specific_handler"; 67 case EHPersonality::MSVC_CXX: 68 return "__CxxFrameHandler3"; 69 case EHPersonality::CoreCLR: 70 return "ProcessCLRException"; 71 case EHPersonality::Rust: 72 return "rust_eh_personality"; 73 case EHPersonality::Wasm_CXX: 74 return "__gxx_wasm_personality_v0"; 75 case EHPersonality::XL_CXX: 76 return "__xlcxx_personality_v1"; 77 case EHPersonality::ZOS_CXX: 78 return "__zos_cxx_personality_v2"; 79 case EHPersonality::Unknown: 80 llvm_unreachable("Unknown EHPersonality!"); 81 } 82 83 llvm_unreachable("Invalid EHPersonality!"); 84 } 85 86 EHPersonality llvm::getDefaultEHPersonality(const Triple &T) { 87 if (T.isPS5()) 88 return EHPersonality::GNU_CXX; 89 else 90 return EHPersonality::GNU_C; 91 } 92 93 bool llvm::canSimplifyInvokeNoUnwind(const Function *F) { 94 EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn()); 95 // We can't simplify any invokes to nounwind functions if the personality 96 // function wants to catch asynch exceptions. The nounwind attribute only 97 // implies that the function does not throw synchronous exceptions. 98 99 // Cannot simplify CXX Personality under AsynchEH 100 const llvm::Module *M = (const llvm::Module *)F->getParent(); 101 bool EHa = M->getModuleFlag("eh-asynch"); 102 return !EHa && !isAsynchronousEHPersonality(Personality); 103 } 104 105 DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) { 106 SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist; 107 BasicBlock *EntryBlock = &F.getEntryBlock(); 108 DenseMap<BasicBlock *, ColorVector> BlockColors; 109 110 // Build up the color map, which maps each block to its set of 'colors'. 111 // For any block B the "colors" of B are the set of funclets F (possibly 112 // including a root "funclet" representing the main function) such that 113 // F will need to directly contain B or a copy of B (where the term "directly 114 // contain" is used to distinguish from being "transitively contained" in 115 // a nested funclet). 116 // 117 // Note: Despite not being a funclet in the truest sense, a catchswitch is 118 // considered to belong to its own funclet for the purposes of coloring. 119 120 DEBUG_WITH_TYPE("win-eh-prepare-coloring", 121 dbgs() << "\nColoring funclets for " << F.getName() << "\n"); 122 123 Worklist.push_back({EntryBlock, EntryBlock}); 124 125 while (!Worklist.empty()) { 126 BasicBlock *Visiting; 127 BasicBlock *Color; 128 std::tie(Visiting, Color) = Worklist.pop_back_val(); 129 DEBUG_WITH_TYPE("win-eh-prepare-coloring", 130 dbgs() << "Visiting " << Visiting->getName() << ", " 131 << Color->getName() << "\n"); 132 Instruction *VisitingHead = Visiting->getFirstNonPHI(); 133 if (VisitingHead->isEHPad()) { 134 // Mark this funclet head as a member of itself. 135 Color = Visiting; 136 } 137 // Note that this is a member of the given color. 138 ColorVector &Colors = BlockColors[Visiting]; 139 if (!is_contained(Colors, Color)) 140 Colors.push_back(Color); 141 else 142 continue; 143 144 DEBUG_WITH_TYPE("win-eh-prepare-coloring", 145 dbgs() << " Assigned color \'" << Color->getName() 146 << "\' to block \'" << Visiting->getName() 147 << "\'.\n"); 148 149 BasicBlock *SuccColor = Color; 150 Instruction *Terminator = Visiting->getTerminator(); 151 if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) { 152 Value *ParentPad = CatchRet->getCatchSwitchParentPad(); 153 if (isa<ConstantTokenNone>(ParentPad)) 154 SuccColor = EntryBlock; 155 else 156 SuccColor = cast<Instruction>(ParentPad)->getParent(); 157 } 158 159 for (BasicBlock *Succ : successors(Visiting)) 160 Worklist.push_back({Succ, SuccColor}); 161 } 162 return BlockColors; 163 } 164