//===- InlineFunction.cpp - Code to perform function inlining -------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
//
// This file implements inlining of a function into a call site, resolving
// parameters and the return value as appropriate.
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Constant.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
-#include "llvm/iTerminators.h"
-#include "llvm/iPHINode.h"
-#include "llvm/iMemory.h"
-#include "llvm/iOther.h"
+#include "llvm/Instructions.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Support/CallSite.h"
#include "llvm/Transforms/Utils/Local.h"
+namespace llvm {
+
+bool InlineFunction(CallInst *CI) { return InlineFunction(CallSite(CI)); }
+bool InlineFunction(InvokeInst *II) { return InlineFunction(CallSite(II)); }
+
// InlineFunction - This function inlines the called function into the basic
// block of the caller. This returns false if it is not possible to inline this
// call. The program is still in a well defined state if this occurs though.
// exists in the instruction stream. Similiarly this will inline a recursive
// function by one level.
//
-bool InlineFunction(CallInst *CI) {
- assert(isa<CallInst>(CI) && "InlineFunction only works on CallInst nodes");
- assert(CI->getParent() && "Instruction not embedded in basic block!");
- assert(CI->getParent()->getParent() && "Instruction not in function!");
+bool InlineFunction(CallSite CS) {
+ Instruction *TheCall = CS.getInstruction();
+ assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
+ "Instruction not in function!");
- const Function *CalledFunc = CI->getCalledFunction();
+ const Function *CalledFunc = CS.getCalledFunction();
if (CalledFunc == 0 || // Can't inline external function or indirect
CalledFunc->isExternal() || // call, or call to a vararg function!
CalledFunc->getFunctionType()->isVarArg()) return false;
- BasicBlock *OrigBB = CI->getParent();
+ BasicBlock *OrigBB = TheCall->getParent();
Function *Caller = OrigBB->getParent();
- // Call splitBasicBlock - The original basic block now ends at the instruction
- // immediately before the call. The original basic block now ends with an
- // unconditional branch to NewBB, and NewBB starts with the call instruction.
- //
- BasicBlock *NewBB = OrigBB->splitBasicBlock(CI,
- CalledFunc->getName()+".entry");
- NewBB->setName(OrigBB->getName()+".split");
+ // We want to clone the entire callee function into the whole between the
+ // "starter" and "ender" blocks. How we accomplish this depends on whether
+ // this is an invoke instruction or a call instruction.
+
+ BasicBlock *InvokeDest = 0; // Exception handling destination
+ std::vector<Value*> InvokeDestPHIValues; // Values for PHI nodes in InvokeDest
+ BasicBlock *AfterCallBB;
+
+ if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
+ InvokeDest = II->getExceptionalDest();
- // Remove (unlink) the CallInst from the start of the new basic block.
- NewBB->getInstList().remove(CI);
+ // If there are PHI nodes in the exceptional destination block, we need to
+ // keep track of which values came into them from this invoke, then remove
+ // the entry for this block.
+ for (BasicBlock::iterator I = InvokeDest->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I) {
+ // Save the value to use for this edge...
+ InvokeDestPHIValues.push_back(PN->getIncomingValueForBlock(OrigBB));
+ }
+
+ // Add an unconditional branch to make this look like the CallInst case...
+ BranchInst *NewBr = new BranchInst(II->getNormalDest(), TheCall);
+
+ // Split the basic block. This guarantees that no PHI nodes will have to be
+ // updated due to new incoming edges, and make the invoke case more
+ // symmetric to the call case.
+ AfterCallBB = OrigBB->splitBasicBlock(NewBr,
+ CalledFunc->getName()+".entry");
+
+ // Remove (unlink) the InvokeInst from the function...
+ OrigBB->getInstList().remove(TheCall);
+
+ } else { // It's a call
+ // If this is a call instruction, we need to split the basic block that the
+ // call lives in.
+ //
+ AfterCallBB = OrigBB->splitBasicBlock(TheCall,
+ CalledFunc->getName()+".entry");
+ // Remove (unlink) the CallInst from the function...
+ AfterCallBB->getInstList().remove(TheCall);
+ }
// If we have a return value generated by this call, convert it into a PHI
// node that gets values from each of the old RET instructions in the original
// function.
//
PHINode *PHI = 0;
- if (!CI->use_empty()) {
+ if (!TheCall->use_empty()) {
// The PHI node should go at the front of the new basic block to merge all
// possible incoming values.
//
- PHI = new PHINode(CalledFunc->getReturnType(), CI->getName(),
- NewBB->begin());
+ PHI = new PHINode(CalledFunc->getReturnType(), TheCall->getName(),
+ AfterCallBB->begin());
// Anything that used the result of the function call should now use the PHI
// node as their operand.
//
- CI->replaceAllUsesWith(PHI);
+ TheCall->replaceAllUsesWith(PHI);
}
// Get an iterator to the last basic block in the function, which will have
// Calculate the vector of arguments to pass into the function cloner...
std::map<const Value*, Value*> ValueMap;
- assert((unsigned)std::distance(CalledFunc->abegin(), CalledFunc->aend()) ==
- CI->getNumOperands()-1 && "No varargs calls can be inlined yet!");
+ assert(std::distance(CalledFunc->abegin(), CalledFunc->aend()) ==
+ std::distance(CS.arg_begin(), CS.arg_end()) &&
+ "No varargs calls can be inlined!");
- unsigned i = 1;
+ CallSite::arg_iterator AI = CS.arg_begin();
for (Function::const_aiterator I = CalledFunc->abegin(), E=CalledFunc->aend();
- I != E; ++I, ++i)
- ValueMap[I] = CI->getOperand(i);
+ I != E; ++I, ++AI)
+ ValueMap[I] = *AI;
- // Since we are now done with the CallInst, we can delete it.
- delete CI;
+ // Since we are now done with the Call/Invoke, we can delete it.
+ delete TheCall;
// Make a vector to capture the return instructions in the cloned function...
std::vector<ReturnInst*> Returns;
- // Populate the value map with all of the globals in the program.
- Module &M = *Caller->getParent();
- for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
- ValueMap[I] = I;
- for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
- ValueMap[I] = I;
-
// Do all of the hard part of cloning the callee into the caller...
CloneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i");
ReturnInst *RI = Returns[i];
BasicBlock *BB = RI->getParent();
- // Add a branch to the merge point where the PHI node would live...
- new BranchInst(NewBB, RI);
+ // Add a branch to the merge point where the PHI node lives if it exists.
+ new BranchInst(AfterCallBB, RI);
if (PHI) { // The PHI node should include this value!
assert(RI->getReturnValue() && "Ret should have value!");
PHI->getParent()->getInstList().erase(PHI);
}
- // Change the branch that used to go to NewBB to branch to the first basic
- // block of the inlined function.
+ // Change the branch that used to go to AfterCallBB to branch to the first
+ // basic block of the inlined function.
//
TerminatorInst *Br = OrigBB->getTerminator();
assert(Br && Br->getOpcode() == Instruction::Br &&
// calculate which instruction they should be inserted before. We insert the
// instructions at the end of the current alloca list.
//
- BasicBlock::iterator InsertPoint = Caller->begin()->begin();
- while (isa<AllocaInst>(InsertPoint)) ++InsertPoint;
-
- for (BasicBlock::iterator I = LastBlock->begin(), E = LastBlock->end();
- I != E; )
- if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
- ++I; // Move to the next instruction
- LastBlock->getInstList().remove(AI);
- Caller->front().getInstList().insert(InsertPoint, AI);
-
- } else {
- ++I;
+ if (isa<AllocaInst>(LastBlock->begin())) {
+ BasicBlock::iterator InsertPoint = Caller->begin()->begin();
+ while (isa<AllocaInst>(InsertPoint)) ++InsertPoint;
+
+ for (BasicBlock::iterator I = LastBlock->begin(), E = LastBlock->end();
+ I != E; )
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I++))
+ if (isa<Constant>(AI->getArraySize())) {
+ LastBlock->getInstList().remove(AI);
+ Caller->front().getInstList().insert(InsertPoint, AI);
+ }
+ }
+
+ // If we just inlined a call due to an invoke instruction, scan the inlined
+ // function checking for function calls that should now be made into invoke
+ // instructions, and for unwind's which should be turned into branches.
+ if (InvokeDest) {
+ for (Function::iterator BB = LastBlock, E = Caller->end(); BB != E; ++BB) {
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
+ // We only need to check for function calls: inlined invoke instructions
+ // require no special handling...
+ if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ // Convert this function call into an invoke instruction...
+
+ // First, split the basic block...
+ BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
+
+ // Next, create the new invoke instruction, inserting it at the end
+ // of the old basic block.
+ InvokeInst *II =
+ new InvokeInst(CI->getCalledValue(), Split, InvokeDest,
+ std::vector<Value*>(CI->op_begin()+1, CI->op_end()),
+ CI->getName(), BB->getTerminator());
+
+ // Make sure that anything using the call now uses the invoke!
+ CI->replaceAllUsesWith(II);
+
+ // Delete the unconditional branch inserted by splitBasicBlock
+ BB->getInstList().pop_back();
+ Split->getInstList().pop_front(); // Delete the original call
+
+ // Update any PHI nodes in the exceptional block to indicate that
+ // there is now a new entry in them.
+ unsigned i = 0;
+ for (BasicBlock::iterator I = InvokeDest->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I, ++i)
+ PN->addIncoming(InvokeDestPHIValues[i], BB);
+
+ // This basic block is now complete, start scanning the next one.
+ break;
+ } else {
+ ++I;
+ }
+ }
+
+ if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
+ // An UnwindInst requires special handling when it gets inlined into an
+ // invoke site. Once this happens, we know that the unwind would cause
+ // a control transfer to the invoke exception destination, so we can
+ // transform it into a direct branch to the exception destination.
+ new BranchInst(InvokeDest, UI);
+
+ // Delete the unwind instruction!
+ UI->getParent()->getInstList().pop_back();
+
+ // Update any PHI nodes in the exceptional block to indicate that
+ // there is now a new entry in them.
+ unsigned i = 0;
+ for (BasicBlock::iterator I = InvokeDest->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I, ++i)
+ PN->addIncoming(InvokeDestPHIValues[i], BB);
+ }
}
+ // Now that everything is happy, we have one final detail. The PHI nodes in
+ // the exception destination block still have entries due to the original
+ // invoke instruction. Eliminate these entries (which might even delete the
+ // PHI node) now.
+ for (BasicBlock::iterator I = InvokeDest->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I)
+ PN->removeIncomingValue(AfterCallBB);
+ }
// Now that the function is correct, make it a little bit nicer. In
// particular, move the basic blocks inserted from the end of the function
// into the space made by splitting the source basic block.
//
- Caller->getBasicBlockList().splice(NewBB, Caller->getBasicBlockList(),
+ Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(),
LastBlock, Caller->end());
// We should always be able to fold the entry block of the function into the
// Okay, continue the CFG cleanup. It's often the case that there is only a
// single return instruction in the callee function. If this is the case,
- // then we have an unconditional branch from the return block to the 'NewBB'.
- // Check for this case, and eliminate the branch is possible.
- SimplifyCFG(NewBB);
+ // then we have an unconditional branch from the return block to the
+ // 'AfterCallBB'. Check for this case, and eliminate the branch is possible.
+ SimplifyCFG(AfterCallBB);
return true;
}
+
+} // End llvm namespace
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