//===- 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.
//
// FIXME: This pass should transform alloca instructions in the called function
-// into malloc/free pairs! Or perhaps it should refuse to inline them!
+// into alloca/dealloca pairs! Or perhaps it should refuse to inline them!
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/Cloning.h"
-#include "llvm/Constant.h"
+#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/CallSite.h"
-#include "llvm/Transforms/Utils/Local.h"
+using namespace llvm;
-bool InlineFunction(CallInst *CI) { return InlineFunction(CallSite(CI)); }
-bool InlineFunction(InvokeInst *II) { return InlineFunction(CallSite(II)); }
+bool llvm::InlineFunction(CallInst *CI) { return InlineFunction(CallSite(CI)); }
+bool llvm::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
// exists in the instruction stream. Similiarly this will inline a recursive
// function by one level.
//
-bool InlineFunction(CallSite CS) {
+bool llvm::InlineFunction(CallSite CS) {
Instruction *TheCall = CS.getInstruction();
assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
"Instruction not in function!");
BasicBlock *OrigBB = TheCall->getParent();
Function *Caller = OrigBB->getParent();
- // 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();
-
- // 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");
-
- // 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(AfterCallBB));
- }
-
- // 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 (!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(), TheCall->getName(),
- AfterCallBB->begin());
-
- // Anything that used the result of the function call should now use the PHI
- // node as their operand.
- //
- TheCall->replaceAllUsesWith(PHI);
- }
-
// Get an iterator to the last basic block in the function, which will have
// the new function inlined after it.
//
Function::iterator LastBlock = &Caller->back();
- // Calculate the vector of arguments to pass into the function cloner...
- std::map<const Value*, Value*> ValueMap;
- assert(std::distance(CalledFunc->abegin(), CalledFunc->aend()) ==
- std::distance(CS.arg_begin(), CS.arg_end()) &&
- "No varargs calls can be inlined!");
-
- CallSite::arg_iterator AI = CS.arg_begin();
- for (Function::const_aiterator I = CalledFunc->abegin(), E=CalledFunc->aend();
- I != E; ++I, ++AI)
- ValueMap[I] = *AI;
-
- // 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...
+ // Make sure to capture all of the return instructions from the cloned
+ // function.
std::vector<ReturnInst*> Returns;
+ { // Scope to destroy ValueMap after cloning.
+ // Calculate the vector of arguments to pass into the function cloner...
+ std::map<const Value*, Value*> ValueMap;
+ assert(std::distance(CalledFunc->abegin(), CalledFunc->aend()) ==
+ std::distance(CS.arg_begin(), CS.arg_end()) &&
+ "No varargs calls can be inlined!");
+
+ CallSite::arg_iterator AI = CS.arg_begin();
+ for (Function::const_aiterator I = CalledFunc->abegin(),
+ E = CalledFunc->aend(); I != E; ++I, ++AI)
+ ValueMap[I] = *AI;
+
+ // Clone the entire body of the callee into the caller.
+ CloneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i");
+ }
- // Do all of the hard part of cloning the callee into the caller...
- CloneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i");
-
- // Loop over all of the return instructions, turning them into unconditional
- // branches to the merge point now...
- for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
- ReturnInst *RI = Returns[i];
- BasicBlock *BB = RI->getParent();
-
- // 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!");
- assert(RI->getReturnValue()->getType() == PHI->getType() &&
- "Ret value not consistent in function!");
- PHI->addIncoming(RI->getReturnValue(), BB);
- }
-
- // Delete the return instruction now
- BB->getInstList().erase(RI);
- }
-
- // Check to see if the PHI node only has one argument. This is a common
- // case resulting from there only being a single return instruction in the
- // function call. Because this is so common, eliminate the PHI node.
- //
- if (PHI && PHI->getNumIncomingValues() == 1) {
- PHI->replaceAllUsesWith(PHI->getIncomingValue(0));
- PHI->getParent()->getInstList().erase(PHI);
- }
-
- // 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 &&
- "splitBasicBlock broken!");
- Br->setOperand(0, ++LastBlock);
+ // Remember the first block that is newly cloned over.
+ Function::iterator FirstNewBlock = LastBlock; ++FirstNewBlock;
// If there are any alloca instructions in the block that used to be the entry
// block for the callee, move them to the entry block of the caller. First
// calculate which instruction they should be inserted before. We insert the
// instructions at the end of the current alloca list.
//
- if (isa<AllocaInst>(LastBlock->begin())) {
+ if (isa<AllocaInst>(FirstNewBlock->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)) {
- ++I; // Move to the next instruction
- LastBlock->getInstList().remove(AI);
- Caller->front().getInstList().insert(InsertPoint, AI);
- } else {
- ++I;
- }
+ for (BasicBlock::iterator I = FirstNewBlock->begin(),
+ E = FirstNewBlock->end(); I != E; )
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I++))
+ if (isa<Constant>(AI->getArraySize())) {
+ // Scan for the block of allocas that we can move over.
+ while (isa<AllocaInst>(I) &&
+ isa<Constant>(cast<AllocaInst>(I)->getArraySize()))
+ ++I;
+
+ // Transfer all of the allocas over in a block. Using splice means
+ // that they instructions aren't removed from the symbol table, then
+ // reinserted.
+ Caller->front().getInstList().splice(InsertPoint,
+ FirstNewBlock->getInstList(),
+ AI, I);
+ }
}
- // 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) {
+ // If we are inlining for an invoke instruction, we must make sure to rewrite
+ // any inlined 'unwind' instructions into branches to the invoke exception
+ // destination, and call instructions into invoke instructions.
+ if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
+ BasicBlock *InvokeDest = II->getUnwindDest();
+ std::vector<Value*> InvokeDestPHIValues;
+
+ // 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(); isa<PHINode>(I); ++I) {
+ PHINode *PN = cast<PHINode>(I);
+ // Save the value to use for this edge...
+ InvokeDestPHIValues.push_back(PN->getIncomingValueForBlock(OrigBB));
+ }
+
+ for (Function::iterator BB = FirstNewBlock, 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;
+ // Convert this function call into an invoke instruction... if it's
+ // not an intrinsic function call (which are known to not throw).
+ if (CI->getCalledFunction() &&
+ CI->getCalledFunction()->getIntrinsicID()) {
+ ++I;
+ } else {
+ // 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();
+ isa<PHINode>(I); ++I, ++i) {
+ PHINode *PN = cast<PHINode>(I);
+ PN->addIncoming(InvokeDestPHIValues[i], BB);
+ }
+
+ // This basic block is now complete, start scanning the next one.
+ break;
+ }
} else {
++I;
}
// 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.
- BranchInst *BI = new BranchInst(InvokeDest, UI);
+ 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();
+ isa<PHINode>(I); ++I, ++i) {
+ PHINode *PN = cast<PHINode>(I);
+ PN->addIncoming(InvokeDestPHIValues[i], BB);
+ }
}
}
// 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);
+ InvokeDest->removePredecessor(II->getParent());
+ }
+
+ // If we cloned in _exactly one_ basic block, and if that block ends in a
+ // return instruction, we splice the body of the inlined callee directly into
+ // the calling basic block.
+ if (Returns.size() == 1 && std::distance(FirstNewBlock, Caller->end()) == 1) {
+ // Move all of the instructions right before the call.
+ OrigBB->getInstList().splice(TheCall, FirstNewBlock->getInstList(),
+ FirstNewBlock->begin(), FirstNewBlock->end());
+ // Remove the cloned basic block.
+ Caller->getBasicBlockList().pop_back();
+
+ // If the call site was an invoke instruction, add a branch to the normal
+ // destination.
+ if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
+ new BranchInst(II->getNormalDest(), TheCall);
+
+ // If the return instruction returned a value, replace uses of the call with
+ // uses of the returned value.
+ if (!TheCall->use_empty())
+ TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
+
+ // Since we are now done with the Call/Invoke, we can delete it.
+ TheCall->getParent()->getInstList().erase(TheCall);
+
+ // Since we are now done with the return instruction, delete it also.
+ Returns[0]->getParent()->getInstList().erase(Returns[0]);
+
+ // We are now done with the inlining.
+ return true;
}
+
+ // Otherwise, we have the normal case, of more than one block to inline or
+ // multiple return sites.
+
+ // We want to clone the entire callee function into the hole between the
+ // "starter" and "ender" blocks. How we accomplish this depends on whether
+ // this is an invoke instruction or a call instruction.
+ BasicBlock *AfterCallBB;
+ if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
+
+ // 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()+".exit");
+
+ } 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()+".exit");
+ }
+
+ // 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 &&
+ "splitBasicBlock broken!");
+ Br->setOperand(0, FirstNewBlock);
+
+
// 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(AfterCallBB, Caller->getBasicBlockList(),
- LastBlock, Caller->end());
+ Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(),
+ FirstNewBlock, Caller->end());
+
+ // Handle all of the return instructions that we just cloned in, and eliminate
+ // any users of the original call/invoke instruction.
+ if (Returns.size() > 1) {
+ // The PHI node should go at the front of the new basic block to merge all
+ // possible incoming values.
+ //
+ PHINode *PHI = 0;
+ if (!TheCall->use_empty()) {
+ 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.
+ //
+ TheCall->replaceAllUsesWith(PHI);
+ }
+
+ // Loop over all of the return instructions, turning them into unconditional
+ // branches to the merge point now, and adding entries to the PHI node as
+ // appropriate.
+ for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
+ ReturnInst *RI = Returns[i];
+
+ if (PHI) {
+ assert(RI->getReturnValue() && "Ret should have value!");
+ assert(RI->getReturnValue()->getType() == PHI->getType() &&
+ "Ret value not consistent in function!");
+ PHI->addIncoming(RI->getReturnValue(), RI->getParent());
+ }
+
+ // Add a branch to the merge point where the PHI node lives if it exists.
+ new BranchInst(AfterCallBB, RI);
+
+ // Delete the return instruction now
+ RI->getParent()->getInstList().erase(RI);
+ }
+
+ } else if (!Returns.empty()) {
+ // Otherwise, if there is exactly one return value, just replace anything
+ // using the return value of the call with the computed value.
+ if (!TheCall->use_empty())
+ TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
+
+ // Splice the code from the return block into the block that it will return
+ // to, which contains the code that was after the call.
+ BasicBlock *ReturnBB = Returns[0]->getParent();
+ AfterCallBB->getInstList().splice(AfterCallBB->begin(),
+ ReturnBB->getInstList());
+
+ // Update PHI nodes that use the ReturnBB to use the AfterCallBB.
+ ReturnBB->replaceAllUsesWith(AfterCallBB);
+
+ // Delete the return instruction now and empty ReturnBB now.
+ Returns[0]->eraseFromParent();
+ ReturnBB->eraseFromParent();
+ } else if (!TheCall->use_empty()) {
+ // No returns, but something is using the return value of the call. Just
+ // nuke the result.
+ TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
+ }
+
+ // Since we are now done with the Call/Invoke, we can delete it.
+ TheCall->eraseFromParent();
// We should always be able to fold the entry block of the function into the
// single predecessor of the block...
assert(cast<BranchInst>(Br)->isUnconditional() && "splitBasicBlock broken!");
BasicBlock *CalleeEntry = cast<BranchInst>(Br)->getSuccessor(0);
- SimplifyCFG(CalleeEntry);
-
- // 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
- // 'AfterCallBB'. Check for this case, and eliminate the branch is possible.
- SimplifyCFG(AfterCallBB);
+
+ // Splice the code entry block into calling block, right before the
+ // unconditional branch.
+ OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());
+ CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes
+
+ // Remove the unconditional branch.
+ OrigBB->getInstList().erase(Br);
+
+ // Now we can remove the CalleeEntry block, which is now empty.
+ Caller->getBasicBlockList().erase(CalleeEntry);
return true;
}
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