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