forked from OSchip/llvm-project
97 lines
2.9 KiB
C++
97 lines
2.9 KiB
C++
|
//===- EscapeEnumerator.cpp -----------------------------------------------===//
|
||
|
|
//
|
||
|
|
// The LLVM Compiler Infrastructure
|
||
|
|
//
|
||
|
|
// This file is distributed under the University of Illinois Open Source
|
||
|
|
// License. See LICENSE.TXT for details.
|
||
|
|
//
|
||
|
|
//===----------------------------------------------------------------------===//
|
||
|
|
//
|
||
|
|
// Defines a helper class that enumerates all possible exits from a function,
|
||
|
|
// including exception handling.
|
||
|
|
//
|
||
|
|
//===----------------------------------------------------------------------===//
|
||
|
|
|
||
|
|
#include "llvm/Transforms/Utils/EscapeEnumerator.h"
|
||
|
|
#include "llvm/Analysis/EHPersonalities.h"
|
||
|
|
#include "llvm/IR/CallSite.h"
|
||
|
|
#include "llvm/IR/Module.h"
|
||
|
|
#include "llvm/Transforms/Utils/Local.h"
|
||
|
|
using namespace llvm;
|
||
|
|
|
||
|
|
static Constant *getDefaultPersonalityFn(Module *M) {
|
||
|
|
LLVMContext &C = M->getContext();
|
||
|
|
Triple T(M->getTargetTriple());
|
||
|
|
EHPersonality Pers = getDefaultEHPersonality(T);
|
||
|
|
return M->getOrInsertFunction(getEHPersonalityName(Pers),
|
||
|
|
FunctionType::get(Type::getInt32Ty(C), true));
|
||
|
|
}
|
||
|
|
|
||
|
|
IRBuilder<> *EscapeEnumerator::Next() {
|
||
|
|
if (Done)
|
||
|
|
return nullptr;
|
||
|
|
|
||
|
|
// Find all 'return', 'resume', and 'unwind' instructions.
|
||
|
|
while (StateBB != StateE) {
|
||
|
|
BasicBlock *CurBB = &*StateBB++;
|
||
|
|
|
||
|
|
// Branches and invokes do not escape, only unwind, resume, and return
|
||
|
|
// do.
|
||
|
|
TerminatorInst *TI = CurBB->getTerminator();
|
||
|
|
if (!isa<ReturnInst>(TI) && !isa<ResumeInst>(TI))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
Builder.SetInsertPoint(TI);
|
||
|
|
return &Builder;
|
||
|
|
}
|
||
|
|
|
||
|
|
Done = true;
|
||
|
|
|
||
|
|
if (!HandleExceptions)
|
||
|
|
return nullptr;
|
||
|
|
|
||
|
|
if (F.doesNotThrow())
|
||
|
|
return nullptr;
|
||
|
|
|
||
|
|
// Find all 'call' instructions that may throw.
|
||
|
|
SmallVector<Instruction *, 16> Calls;
|
||
|
|
for (BasicBlock &BB : F)
|
||
|
|
for (Instruction &II : BB)
|
||
|
|
if (CallInst *CI = dyn_cast<CallInst>(&II))
|
||
|
|
if (!CI->doesNotThrow())
|
||
|
|
Calls.push_back(CI);
|
||
|
|
|
||
|
|
if (Calls.empty())
|
||
|
|
return nullptr;
|
||
|
|
|
||
|
|
// Create a cleanup block.
|
||
|
|
LLVMContext &C = F.getContext();
|
||
|
|
BasicBlock *CleanupBB = BasicBlock::Create(C, CleanupBBName, &F);
|
||
|
|
Type *ExnTy =
|
||
|
|
StructType::get(Type::getInt8PtrTy(C), Type::getInt32Ty(C), nullptr);
|
||
|
|
if (!F.hasPersonalityFn()) {
|
||
|
|
Constant *PersFn = getDefaultPersonalityFn(F.getParent());
|
||
|
|
F.setPersonalityFn(PersFn);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (isFuncletEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) {
|
||
|
|
report_fatal_error("Funclet EH not supported");
|
||
|
|
}
|
||
|
|
|
||
|
|
LandingPadInst *LPad =
|
||
|
|
LandingPadInst::Create(ExnTy, 1, "cleanup.lpad", CleanupBB);
|
||
|
|
LPad->setCleanup(true);
|
||
|
|
ResumeInst *RI = ResumeInst::Create(LPad, CleanupBB);
|
||
|
|
|
||
|
|
// Transform the 'call' instructions into 'invoke's branching to the
|
||
|
|
// cleanup block. Go in reverse order to make prettier BB names.
|
||
|
|
SmallVector<Value *, 16> Args;
|
||
|
|
for (unsigned I = Calls.size(); I != 0;) {
|
||
|
|
CallInst *CI = cast<CallInst>(Calls[--I]);
|
||
|
|
changeToInvokeAndSplitBasicBlock(CI, CleanupBB);
|
||
|
|
}
|
||
|
|
|
||
|
|
Builder.SetInsertPoint(RI);
|
||
|
|
return &Builder;
|
||
|
|
}
|