llvm-6502/lib/Transforms/Utils/LowerInvoke.cpp
Mark Seaborn 9bb9615e1f Remove LowerInvoke's obsolete "-enable-correct-eh-support" option
This option caused LowerInvoke to generate code using SJLJ-based
exception handling, but there is no code left that interprets the
jmp_buf stack that the resulting code maintained (llvm.sjljeh.jblist).
This option has been obsolete for a while, and replaced by
SjLjEHPrepare.

This leaves the default behaviour of LowerInvoke, which is to convert
invokes to calls.

Differential Revision: http://llvm-reviews.chandlerc.com/D3136

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204388 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-20 19:54:47 +00:00

80 lines
2.8 KiB
C++

//===- LowerInvoke.cpp - Eliminate Invoke instructions --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This transformation is designed for use by code generators which do not yet
// support stack unwinding. This pass converts 'invoke' instructions to 'call'
// instructions, so that any exception-handling 'landingpad' blocks become dead
// code (which can be removed by running the '-simplifycfg' pass afterwards).
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "lowerinvoke"
#include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
STATISTIC(NumInvokes, "Number of invokes replaced");
namespace {
class LowerInvoke : public FunctionPass {
public:
static char ID; // Pass identification, replacement for typeid
explicit LowerInvoke() : FunctionPass(ID) {
initializeLowerInvokePass(*PassRegistry::getPassRegistry());
}
bool runOnFunction(Function &F) override;
};
}
char LowerInvoke::ID = 0;
INITIALIZE_PASS(LowerInvoke, "lowerinvoke",
"Lower invoke and unwind, for unwindless code generators",
false, false)
char &llvm::LowerInvokePassID = LowerInvoke::ID;
// Public Interface To the LowerInvoke pass.
FunctionPass *llvm::createLowerInvokePass() {
return new LowerInvoke();
}
bool LowerInvoke::runOnFunction(Function &F) {
bool Changed = false;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
SmallVector<Value*,16> CallArgs(II->op_begin(), II->op_end() - 3);
// Insert a normal call instruction...
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
CallArgs, "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
NewCall->setDebugLoc(II->getDebugLoc());
II->replaceAllUsesWith(NewCall);
// Insert an unconditional branch to the normal destination.
BranchInst::Create(II->getNormalDest(), II);
// Remove any PHI node entries from the exception destination.
II->getUnwindDest()->removePredecessor(BB);
// Remove the invoke instruction now.
BB->getInstList().erase(II);
++NumInvokes; Changed = true;
}
return Changed;
}