//===- 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!
-//
//===----------------------------------------------------------------------===//
#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/Analysis/CallGraph.h"
+#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/CallSite.h"
-#include "llvm/Transforms/Utils/Local.h"
+using namespace llvm;
+
+bool llvm::InlineFunction(CallInst *CI, CallGraph *CG, const TargetData *TD) {
+ return InlineFunction(CallSite(CI), CG, TD);
+}
+bool llvm::InlineFunction(InvokeInst *II, CallGraph *CG, const TargetData *TD) {
+ return InlineFunction(CallSite(II), CG, TD);
+}
+
+/// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls
+/// in the body of the inlined function into invokes and turn unwind
+/// instructions into branches to the invoke unwind dest.
+///
+/// II is the invoke instruction begin inlined. FirstNewBlock is the first
+/// block of the inlined code (the last block is the end of the function),
+/// and InlineCodeInfo is information about the code that got inlined.
+static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
+ ClonedCodeInfo &InlinedCodeInfo) {
+ BasicBlock *InvokeDest = II->getUnwindDest();
+ std::vector<Value*> InvokeDestPHIValues;
+
+ // If there are PHI nodes in the unwind destination block, we need to
+ // keep track of which values came into them from this invoke, then remove
+ // the entry for this block.
+ BasicBlock *InvokeBlock = II->getParent();
+ 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(InvokeBlock));
+ }
+
+ Function *Caller = FirstNewBlock->getParent();
+
+ // The inlined code is currently at the end of the function, scan from the
+ // start of the inlined code to its end, checking for stuff we need to
+ // rewrite.
+ if (InlinedCodeInfo.ContainsCalls || InlinedCodeInfo.ContainsUnwinds) {
+ for (Function::iterator BB = FirstNewBlock, E = Caller->end();
+ BB != E; ++BB) {
+ if (InlinedCodeInfo.ContainsCalls) {
+ for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ){
+ Instruction *I = BBI++;
+
+ // We only need to check for function calls: inlined invoke
+ // instructions require no special handling.
+ if (!isa<CallInst>(I)) continue;
+ CallInst *CI = cast<CallInst>(I);
+
+ // If this call cannot unwind, don't convert it to an invoke.
+ if (CI->doesNotThrow())
+ continue;
+
+ // 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.
+ SmallVector<Value*, 8> InvokeArgs(CI->op_begin()+1, CI->op_end());
+ InvokeInst *II =
+ new InvokeInst(CI->getCalledValue(), Split, InvokeDest,
+ InvokeArgs.begin(), InvokeArgs.end(),
+ CI->getName(), BB->getTerminator());
+ II->setCallingConv(CI->getCallingConv());
+ II->setParamAttrs(CI->getParamAttrs());
+
+ // 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;
+ }
+ }
+
+ 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();
+ isa<PHINode>(I); ++I, ++i) {
+ PHINode *PN = cast<PHINode>(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.
+ InvokeDest->removePredecessor(II->getParent());
+}
+
+/// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
+/// into the caller, update the specified callgraph to reflect the changes we
+/// made. Note that it's possible that not all code was copied over, so only
+/// some edges of the callgraph will be remain.
+static void UpdateCallGraphAfterInlining(const Function *Caller,
+ const Function *Callee,
+ Function::iterator FirstNewBlock,
+ DenseMap<const Value*, Value*> &ValueMap,
+ CallGraph &CG) {
+ // Update the call graph by deleting the edge from Callee to Caller
+ CallGraphNode *CalleeNode = CG[Callee];
+ CallGraphNode *CallerNode = CG[Caller];
+ CallerNode->removeCallEdgeTo(CalleeNode);
+
+ // Since we inlined some uninlined call sites in the callee into the caller,
+ // add edges from the caller to all of the callees of the callee.
+ for (CallGraphNode::iterator I = CalleeNode->begin(),
+ E = CalleeNode->end(); I != E; ++I) {
+ const Instruction *OrigCall = I->first.getInstruction();
+
+ DenseMap<const Value*, Value*>::iterator VMI = ValueMap.find(OrigCall);
+ // Only copy the edge if the call was inlined!
+ if (VMI != ValueMap.end() && VMI->second) {
+ // If the call was inlined, but then constant folded, there is no edge to
+ // add. Check for this case.
+ if (Instruction *NewCall = dyn_cast<Instruction>(VMI->second))
+ CallerNode->addCalledFunction(CallSite::get(NewCall), I->second);
+ }
+ }
+}
-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.
//
-// Note that this only does one level of inlining. For example, if the
-// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
+// Note that this only does one level of inlining. For example, if the
+// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
// exists in the instruction stream. Similiarly this will inline a recursive
// function by one level.
//
-bool InlineFunction(CallSite CS) {
+bool llvm::InlineFunction(CallSite CS, CallGraph *CG, const TargetData *TD) {
Instruction *TheCall = CS.getInstruction();
assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
"Instruction not in function!");
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->isDeclaration() || // call, or call to a vararg function!
CalledFunc->getFunctionType()->isVarArg()) return false;
- 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);
+ // If the call to the callee is a non-tail call, we must clear the 'tail'
+ // flags on any calls that we inline.
+ bool MustClearTailCallFlags =
+ isa<CallInst>(TheCall) && !cast<CallInst>(TheCall)->isTailCall();
- } 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 the call to the callee cannot throw, set the 'nounwind' flag on any
+ // calls that we inline.
+ bool MarkNoUnwind = CS.doesNotThrow();
- // 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());
+ BasicBlock *OrigBB = TheCall->getParent();
+ Function *Caller = OrigBB->getParent();
- // Anything that used the result of the function call should now use the PHI
- // node as their operand.
- //
- TheCall->replaceAllUsesWith(PHI);
+
+ // GC poses two hazards to inlining, which only occur when the callee has GC:
+ // 1. If the caller has no GC, then the callee's GC must be propagated to the
+ // caller.
+ // 2. If the caller has a differing GC, it is invalid to inline.
+ if (CalledFunc->hasCollector()) {
+ if (!Caller->hasCollector())
+ Caller->setCollector(CalledFunc->getCollector());
+ else if (CalledFunc->getCollector() != Caller->getCollector())
+ return false;
}
-
+
+
// 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;
-
- // 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);
+ ClonedCodeInfo InlinedFunctionInfo;
+ Function::iterator FirstNewBlock;
+
+ { // Scope to destroy ValueMap after cloning.
+ DenseMap<const Value*, Value*> ValueMap;
+
+ // Calculate the vector of arguments to pass into the function cloner, which
+ // matches up the formal to the actual argument values.
+ assert(std::distance(CalledFunc->arg_begin(), CalledFunc->arg_end()) ==
+ std::distance(CS.arg_begin(), CS.arg_end()) &&
+ "No varargs calls can be inlined!");
+ CallSite::arg_iterator AI = CS.arg_begin();
+ for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
+ E = CalledFunc->arg_end(); I != E; ++I, ++AI)
+ ValueMap[I] = *AI;
+
+ // We want the inliner to prune the code as it copies. We would LOVE to
+ // have no dead or constant instructions leftover after inlining occurs
+ // (which can happen, e.g., because an argument was constant), but we'll be
+ // happy with whatever the cloner can do.
+ CloneAndPruneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i",
+ &InlinedFunctionInfo, TD);
+
+ // Remember the first block that is newly cloned over.
+ FirstNewBlock = LastBlock; ++FirstNewBlock;
+
+ // Update the callgraph if requested.
+ if (CG)
+ UpdateCallGraphAfterInlining(Caller, CalledFunc, FirstNewBlock, ValueMap,
+ *CG);
}
-
- // 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);
-
+
// 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())) {
+ {
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++))
+ for (BasicBlock::iterator I = FirstNewBlock->begin(),
+ E = FirstNewBlock->end(); I != E; )
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I++)) {
+ // If the alloca is now dead, remove it. This often occurs due to code
+ // specialization.
+ if (AI->use_empty()) {
+ AI->eraseFromParent();
+ continue;
+ }
+
if (isa<Constant>(AI->getArraySize())) {
- LastBlock->getInstList().remove(AI);
- Caller->front().getInstList().insert(InsertPoint, AI);
+ // Scan for the block of allocas that we can move over, and move them
+ // all at once.
+ while (isa<AllocaInst>(I) &&
+ isa<Constant>(cast<AllocaInst>(I)->getArraySize()))
+ ++I;
+
+ // Transfer all of the allocas over in a block. Using splice means
+ // that the instructions aren't removed from the symbol table, then
+ // reinserted.
+ Caller->getEntryBlock().getInstList().splice(
+ InsertPoint,
+ FirstNewBlock->getInstList(),
+ AI, I);
+ }
+ }
+ }
+
+ // If the inlined code contained dynamic alloca instructions, wrap the inlined
+ // code with llvm.stacksave/llvm.stackrestore intrinsics.
+ if (InlinedFunctionInfo.ContainsDynamicAllocas) {
+ Module *M = Caller->getParent();
+ const Type *BytePtr = PointerType::getUnqual(Type::Int8Ty);
+ // Get the two intrinsics we care about.
+ Constant *StackSave, *StackRestore;
+ StackSave = M->getOrInsertFunction("llvm.stacksave", BytePtr, NULL);
+ StackRestore = M->getOrInsertFunction("llvm.stackrestore", Type::VoidTy,
+ BytePtr, NULL);
+
+ // If we are preserving the callgraph, add edges to the stacksave/restore
+ // functions for the calls we insert.
+ CallGraphNode *StackSaveCGN = 0, *StackRestoreCGN = 0, *CallerNode = 0;
+ if (CG) {
+ // We know that StackSave/StackRestore are Function*'s, because they are
+ // intrinsics which must have the right types.
+ StackSaveCGN = CG->getOrInsertFunction(cast<Function>(StackSave));
+ StackRestoreCGN = CG->getOrInsertFunction(cast<Function>(StackRestore));
+ CallerNode = (*CG)[Caller];
+ }
+
+ // Insert the llvm.stacksave.
+ CallInst *SavedPtr = new CallInst(StackSave, "savedstack",
+ FirstNewBlock->begin());
+ if (CG) CallerNode->addCalledFunction(SavedPtr, StackSaveCGN);
+
+ // Insert a call to llvm.stackrestore before any return instructions in the
+ // inlined function.
+ for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
+ CallInst *CI = new CallInst(StackRestore, SavedPtr, "", Returns[i]);
+ if (CG) CallerNode->addCalledFunction(CI, StackRestoreCGN);
+ }
+
+ // Count the number of StackRestore calls we insert.
+ unsigned NumStackRestores = Returns.size();
+
+ // If we are inlining an invoke instruction, insert restores before each
+ // unwind. These unwinds will be rewritten into branches later.
+ if (InlinedFunctionInfo.ContainsUnwinds && isa<InvokeInst>(TheCall)) {
+ for (Function::iterator BB = FirstNewBlock, E = Caller->end();
+ BB != E; ++BB)
+ if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
+ new CallInst(StackRestore, SavedPtr, "", UI);
+ ++NumStackRestores;
}
+ }
}
- // 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 we are inlining tail call instruction through a call site that isn't
+ // marked 'tail', we must remove the tail marker for any calls in the inlined
+ // code. Also, calls inlined through a 'nounwind' call site should be marked
+ // 'nounwind'.
+ if (InlinedFunctionInfo.ContainsCalls &&
+ (MustClearTailCallFlags || MarkNoUnwind)) {
+ for (Function::iterator BB = FirstNewBlock, E = Caller->end();
+ BB != E; ++BB)
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
if (CallInst *CI = dyn_cast<CallInst>(I)) {
- // Convert this function call into an invoke instruction...
+ if (MustClearTailCallFlags)
+ CI->setTailCall(false);
+ if (MarkNoUnwind)
+ CI->setDoesNotThrow();
+ }
+ }
- // 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());
+ // If we are inlining through a 'nounwind' call site then any inlined 'unwind'
+ // instructions are unreachable.
+ if (InlinedFunctionInfo.ContainsUnwinds && MarkNoUnwind)
+ for (Function::iterator BB = FirstNewBlock, E = Caller->end();
+ BB != E; ++BB) {
+ TerminatorInst *Term = BB->getTerminator();
+ if (isa<UnwindInst>(Term)) {
+ new UnreachableInst(Term);
+ BB->getInstList().erase(Term);
+ }
+ }
- // Make sure that anything using the call now uses the invoke!
- CI->replaceAllUsesWith(II);
+ // 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))
+ HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo);
+
+ // 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;
+ }
- // 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);
+ // Otherwise, we have the normal case, of more than one block to inline or
+ // multiple return sites.
- // This basic block is now complete, start scanning the next one.
- break;
- } else {
- ++I;
- }
- }
+ // 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)) {
- 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.
- BranchInst *BI = new BranchInst(InvokeDest, UI);
+ // Add an unconditional branch to make this look like the CallInst case...
+ BranchInst *NewBr = new BranchInst(II->getNormalDest(), TheCall);
- // Delete the unwind instruction!
- UI->getParent()->getInstList().pop_back();
- }
- }
+ // 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");
- // 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);
+ } 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);
+
+ // 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);
- // 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);
return true;
}
projects / oota-llvm.git / blobdiff