1 //===- LibCallSemantics.cpp - Describe library semantics ------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements interfaces that can be used to describe language 11 // specific runtime library interfaces (e.g. libc, libm, etc) to LLVM 12 // optimizers. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "llvm/Analysis/LibCallSemantics.h" 17 #include "llvm/ADT/StringMap.h" 18 #include "llvm/ADT/StringSwitch.h" 19 #include "llvm/IR/Function.h" 20 using namespace llvm; 21 22 /// This impl pointer in ~LibCallInfo is actually a StringMap. This 23 /// helper does the cast. 24 static StringMap<const LibCallFunctionInfo*> *getMap(void *Ptr) { 25 return static_cast<StringMap<const LibCallFunctionInfo*> *>(Ptr); 26 } 27 28 LibCallInfo::~LibCallInfo() { 29 delete getMap(Impl); 30 } 31 32 const LibCallLocationInfo &LibCallInfo::getLocationInfo(unsigned LocID) const { 33 // Get location info on the first call. 34 if (NumLocations == 0) 35 NumLocations = getLocationInfo(Locations); 36 37 assert(LocID < NumLocations && "Invalid location ID!"); 38 return Locations[LocID]; 39 } 40 41 42 /// Return the LibCallFunctionInfo object corresponding to 43 /// the specified function if we have it. If not, return null. 44 const LibCallFunctionInfo * 45 LibCallInfo::getFunctionInfo(const Function *F) const { 46 StringMap<const LibCallFunctionInfo*> *Map = getMap(Impl); 47 48 /// If this is the first time we are querying for this info, lazily construct 49 /// the StringMap to index it. 50 if (!Map) { 51 Impl = Map = new StringMap<const LibCallFunctionInfo*>(); 52 53 const LibCallFunctionInfo *Array = getFunctionInfoArray(); 54 if (!Array) return nullptr; 55 56 // We now have the array of entries. Populate the StringMap. 57 for (unsigned i = 0; Array[i].Name; ++i) 58 (*Map)[Array[i].Name] = Array+i; 59 } 60 61 // Look up this function in the string map. 62 return Map->lookup(F->getName()); 63 } 64 65 /// See if the given exception handling personality function is one that we 66 /// understand. If so, return a description of it; otherwise return Unknown. 67 EHPersonality llvm::classifyEHPersonality(const Value *Pers) { 68 const Function *F = dyn_cast<Function>(Pers->stripPointerCasts()); 69 if (!F) 70 return EHPersonality::Unknown; 71 return StringSwitch<EHPersonality>(F->getName()) 72 .Case("__gnat_eh_personality", EHPersonality::GNU_Ada) 73 .Case("__gxx_personality_v0", EHPersonality::GNU_CXX) 74 .Case("__gcc_personality_v0", EHPersonality::GNU_C) 75 .Case("__objc_personality_v0", EHPersonality::GNU_ObjC) 76 .Case("__except_handler3", EHPersonality::MSVC_X86SEH) 77 .Case("__except_handler4", EHPersonality::MSVC_X86SEH) 78 .Case("__C_specific_handler", EHPersonality::MSVC_Win64SEH) 79 .Case("__CxxFrameHandler3", EHPersonality::MSVC_CXX) 80 .Default(EHPersonality::Unknown); 81 } 82 83 bool llvm::canSimplifyInvokeNoUnwind(const InvokeInst *II) { 84 const LandingPadInst *LP = II->getLandingPadInst(); 85 EHPersonality Personality = classifyEHPersonality(LP->getPersonalityFn()); 86 // We can't simplify any invokes to nounwind functions if the personality 87 // function wants to catch asynch exceptions. The nounwind attribute only 88 // implies that the function does not throw synchronous exceptions. 89 return !isAsynchronousEHPersonality(Personality); 90 } 91
