EHPersonalities.cpp
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//===- EHPersonalities.cpp - Compute EH-related information ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
/// See if the given exception handling personality function is one that we
/// understand. If so, return a description of it; otherwise return Unknown.
EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
const Function *F =
Pers ? dyn_cast<Function>(Pers->stripPointerCasts()) : nullptr;
if (!F)
return EHPersonality::Unknown;
return StringSwitch<EHPersonality>(F->getName())
.Case("__gnat_eh_personality", EHPersonality::GNU_Ada)
.Case("__gxx_personality_v0", EHPersonality::GNU_CXX)
.Case("__gxx_personality_seh0", EHPersonality::GNU_CXX)
.Case("__gxx_personality_sj0", EHPersonality::GNU_CXX_SjLj)
.Case("__gcc_personality_v0", EHPersonality::GNU_C)
.Case("__gcc_personality_seh0", EHPersonality::GNU_C)
.Case("__gcc_personality_sj0", EHPersonality::GNU_C_SjLj)
.Case("__objc_personality_v0", EHPersonality::GNU_ObjC)
.Case("_except_handler3", EHPersonality::MSVC_X86SEH)
.Case("_except_handler4", EHPersonality::MSVC_X86SEH)
.Case("__C_specific_handler", EHPersonality::MSVC_Win64SEH)
.Case("__CxxFrameHandler3", EHPersonality::MSVC_CXX)
.Case("ProcessCLRException", EHPersonality::CoreCLR)
.Case("rust_eh_personality", EHPersonality::Rust)
.Case("__gxx_wasm_personality_v0", EHPersonality::Wasm_CXX)
.Default(EHPersonality::Unknown);
}
StringRef llvm::getEHPersonalityName(EHPersonality Pers) {
switch (Pers) {
case EHPersonality::GNU_Ada: return "__gnat_eh_personality";
case EHPersonality::GNU_CXX: return "__gxx_personality_v0";
case EHPersonality::GNU_CXX_SjLj: return "__gxx_personality_sj0";
case EHPersonality::GNU_C: return "__gcc_personality_v0";
case EHPersonality::GNU_C_SjLj: return "__gcc_personality_sj0";
case EHPersonality::GNU_ObjC: return "__objc_personality_v0";
case EHPersonality::MSVC_X86SEH: return "_except_handler3";
case EHPersonality::MSVC_Win64SEH: return "__C_specific_handler";
case EHPersonality::MSVC_CXX: return "__CxxFrameHandler3";
case EHPersonality::CoreCLR: return "ProcessCLRException";
case EHPersonality::Rust: return "rust_eh_personality";
case EHPersonality::Wasm_CXX: return "__gxx_wasm_personality_v0";
case EHPersonality::Unknown: llvm_unreachable("Unknown EHPersonality!");
}
llvm_unreachable("Invalid EHPersonality!");
}
EHPersonality llvm::getDefaultEHPersonality(const Triple &T) {
return EHPersonality::GNU_C;
}
bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
// We can't simplify any invokes to nounwind functions if the personality
// function wants to catch asynch exceptions. The nounwind attribute only
// implies that the function does not throw synchronous exceptions.
return !isAsynchronousEHPersonality(Personality);
}
DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
BasicBlock *EntryBlock = &F.getEntryBlock();
DenseMap<BasicBlock *, ColorVector> BlockColors;
// Build up the color map, which maps each block to its set of 'colors'.
// For any block B the "colors" of B are the set of funclets F (possibly
// including a root "funclet" representing the main function) such that
// F will need to directly contain B or a copy of B (where the term "directly
// contain" is used to distinguish from being "transitively contained" in
// a nested funclet).
//
// Note: Despite not being a funclet in the truest sense, a catchswitch is
// considered to belong to its own funclet for the purposes of coloring.
DEBUG_WITH_TYPE("winehprepare-coloring", dbgs() << "\nColoring funclets for "
<< F.getName() << "\n");
Worklist.push_back({EntryBlock, EntryBlock});
while (!Worklist.empty()) {
BasicBlock *Visiting;
BasicBlock *Color;
std::tie(Visiting, Color) = Worklist.pop_back_val();
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << "Visiting " << Visiting->getName() << ", "
<< Color->getName() << "\n");
Instruction *VisitingHead = Visiting->getFirstNonPHI();
if (VisitingHead->isEHPad()) {
// Mark this funclet head as a member of itself.
Color = Visiting;
}
// Note that this is a member of the given color.
ColorVector &Colors = BlockColors[Visiting];
if (!is_contained(Colors, Color))
Colors.push_back(Color);
else
continue;
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << " Assigned color \'" << Color->getName()
<< "\' to block \'" << Visiting->getName()
<< "\'.\n");
BasicBlock *SuccColor = Color;
Instruction *Terminator = Visiting->getTerminator();
if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
Value *ParentPad = CatchRet->getCatchSwitchParentPad();
if (isa<ConstantTokenNone>(ParentPad))
SuccColor = EntryBlock;
else
SuccColor = cast<Instruction>(ParentPad)->getParent();
}
for (BasicBlock *Succ : successors(Visiting))
Worklist.push_back({Succ, SuccColor});
}
return BlockColors;
}