forked from OSchip/llvm-project
103 lines
3.8 KiB
C++
103 lines
3.8 KiB
C++
//===- LibCallSemantics.cpp - Describe library semantics ------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements interfaces that can be used to describe language
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// specific runtime library interfaces (e.g. libc, libm, etc) to LLVM
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// optimizers.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/LibCallSemantics.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/IR/Function.h"
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using namespace llvm;
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/// This impl pointer in ~LibCallInfo is actually a StringMap. This
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/// helper does the cast.
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static StringMap<const LibCallFunctionInfo*> *getMap(void *Ptr) {
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return static_cast<StringMap<const LibCallFunctionInfo*> *>(Ptr);
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}
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LibCallInfo::~LibCallInfo() {
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delete getMap(Impl);
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}
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const LibCallLocationInfo &LibCallInfo::getLocationInfo(unsigned LocID) const {
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// Get location info on the first call.
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if (NumLocations == 0)
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NumLocations = getLocationInfo(Locations);
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assert(LocID < NumLocations && "Invalid location ID!");
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return Locations[LocID];
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}
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/// Return the LibCallFunctionInfo object corresponding to
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/// the specified function if we have it. If not, return null.
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const LibCallFunctionInfo *
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LibCallInfo::getFunctionInfo(const Function *F) const {
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StringMap<const LibCallFunctionInfo*> *Map = getMap(Impl);
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/// If this is the first time we are querying for this info, lazily construct
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/// the StringMap to index it.
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if (!Map) {
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Impl = Map = new StringMap<const LibCallFunctionInfo*>();
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const LibCallFunctionInfo *Array = getFunctionInfoArray();
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if (!Array) return nullptr;
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// We now have the array of entries. Populate the StringMap.
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for (unsigned i = 0; Array[i].Name; ++i)
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(*Map)[Array[i].Name] = Array+i;
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}
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// Look up this function in the string map.
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return Map->lookup(F->getName());
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}
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/// See if the given exception handling personality function is one that we
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/// understand. If so, return a description of it; otherwise return Unknown.
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EHPersonality llvm::classifyEHPersonality(Value *Pers) {
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Function *F = dyn_cast<Function>(Pers->stripPointerCasts());
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if (!F)
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return EHPersonality::Unknown;
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return StringSwitch<EHPersonality>(F->getName())
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.Case("__gnat_eh_personality", EHPersonality::GNU_Ada)
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.Case("__gxx_personality_v0", EHPersonality::GNU_CXX)
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.Case("__gcc_personality_v0", EHPersonality::GNU_C)
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.Case("__objc_personality_v0", EHPersonality::GNU_ObjC)
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.Case("__except_handler3", EHPersonality::MSVC_X86SEH)
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.Case("__except_handler4", EHPersonality::MSVC_X86SEH)
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.Case("__C_specific_handler", EHPersonality::MSVC_Win64SEH)
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.Case("__CxxFrameHandler3", EHPersonality::MSVC_CXX)
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.Default(EHPersonality::Unknown);
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}
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bool llvm::isAsynchronousEHPersonality(EHPersonality Pers) {
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// The two SEH personality functions can catch asynch exceptions. We assume
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// unknown personalities don't catch asynch exceptions.
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switch (Pers) {
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case EHPersonality::MSVC_X86SEH:
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case EHPersonality::MSVC_Win64SEH:
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return true;
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default: return false;
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}
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llvm_unreachable("invalid enum");
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}
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bool llvm::canSimplifyInvokeNoUnwind(const InvokeInst *II) {
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const LandingPadInst *LP = II->getLandingPadInst();
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EHPersonality Personality = classifyEHPersonality(LP->getPersonalityFn());
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// We can't simplify any invokes to nounwind functions if the personality
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// function wants to catch asynch exceptions. The nounwind attribute only
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// implies that the function does not throw synchronous exceptions.
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return !isAsynchronousEHPersonality(Personality);
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}
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