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llvm/lib/Transforms/Utils/InlineFunction.cpp
Chandler Carruth 06cb8ed006 Move llvm/Support/IRBuilder.h -> llvm/IRBuilder.h 
This was always part of the VMCore library out of necessity -- it deals
entirely in the IR. The .cpp file in fact was already part of the VMCore
library. This is just a mechanical move.

I've tried to go through and re-apply the coding standard's preferred
header sort, but at 40-ish files, I may have gotten some wrong. Please
let me know if so.

I'll be committing the corresponding updates to Clang and Polly, and
Duncan has DragonEgg.

Thanks to Bill and Eric for giving the green light for this bit of cleanup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159421 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-29 12:38:19 +00:00

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//===- InlineFunction.cpp - Code to perform function inlining -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file 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/Attributes.h"
#include "llvm/Constants.h"
#include "llvm/DebugInfo.h"
#include "llvm/DerivedTypes.h"
#include "llvm/IRBuilder.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Intrinsics.h"
#include "llvm/Module.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI,
bool InsertLifetime) {
return InlineFunction(CallSite(CI), IFI, InsertLifetime);
}
bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
bool InsertLifetime) {
return InlineFunction(CallSite(II), IFI, InsertLifetime);
}
namespace {
/// A class for recording information about inlining through an invoke.
class InvokeInliningInfo {
BasicBlock *OuterResumeDest; ///< Destination of the invoke's unwind.
BasicBlock *InnerResumeDest; ///< Destination for the callee's resume.
LandingPadInst *CallerLPad; ///< LandingPadInst associated with the invoke.
PHINode *InnerEHValuesPHI; ///< PHI for EH values from landingpad insts.
SmallVector<Value*, 8> UnwindDestPHIValues;
public:
InvokeInliningInfo(InvokeInst *II)
: OuterResumeDest(II->getUnwindDest()), InnerResumeDest(0),
CallerLPad(0), InnerEHValuesPHI(0) {
// If there are PHI nodes in the unwind destination block, we need to keep
// track of which values came into them from the invoke before removing
// the edge from this block.
llvm::BasicBlock *InvokeBB = II->getParent();
BasicBlock::iterator I = OuterResumeDest->begin();
for (; isa<PHINode>(I); ++I) {
// Save the value to use for this edge.
PHINode *PHI = cast<PHINode>(I);
UnwindDestPHIValues.push_back(PHI->getIncomingValueForBlock(InvokeBB));
}
CallerLPad = cast<LandingPadInst>(I);
}
/// getOuterResumeDest - The outer unwind destination is the target of
/// unwind edges introduced for calls within the inlined function.
BasicBlock *getOuterResumeDest() const {
return OuterResumeDest;
}
BasicBlock *getInnerResumeDest();
LandingPadInst *getLandingPadInst() const { return CallerLPad; }
/// forwardResume - Forward the 'resume' instruction to the caller's landing
/// pad block. When the landing pad block has only one predecessor, this is
/// a simple branch. When there is more than one predecessor, we need to
/// split the landing pad block after the landingpad instruction and jump
/// to there.
void forwardResume(ResumeInst *RI);
/// addIncomingPHIValuesFor - Add incoming-PHI values to the unwind
/// destination block for the given basic block, using the values for the
/// original invoke's source block.
void addIncomingPHIValuesFor(BasicBlock *BB) const {
addIncomingPHIValuesForInto(BB, OuterResumeDest);
}
void addIncomingPHIValuesForInto(BasicBlock *src, BasicBlock *dest) const {
BasicBlock::iterator I = dest->begin();
for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
PHINode *phi = cast<PHINode>(I);
phi->addIncoming(UnwindDestPHIValues[i], src);
}
}
};
}
/// getInnerResumeDest - Get or create a target for the branch from ResumeInsts.
BasicBlock *InvokeInliningInfo::getInnerResumeDest() {
if (InnerResumeDest) return InnerResumeDest;
// Split the landing pad.
BasicBlock::iterator SplitPoint = CallerLPad; ++SplitPoint;
InnerResumeDest =
OuterResumeDest->splitBasicBlock(SplitPoint,
OuterResumeDest->getName() + ".body");
// The number of incoming edges we expect to the inner landing pad.
const unsigned PHICapacity = 2;
// Create corresponding new PHIs for all the PHIs in the outer landing pad.
BasicBlock::iterator InsertPoint = InnerResumeDest->begin();
BasicBlock::iterator I = OuterResumeDest->begin();
for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
PHINode *OuterPHI = cast<PHINode>(I);
PHINode *InnerPHI = PHINode::Create(OuterPHI->getType(), PHICapacity,
OuterPHI->getName() + ".lpad-body",
InsertPoint);
OuterPHI->replaceAllUsesWith(InnerPHI);
InnerPHI->addIncoming(OuterPHI, OuterResumeDest);
}
// Create a PHI for the exception values.
InnerEHValuesPHI = PHINode::Create(CallerLPad->getType(), PHICapacity,
"eh.lpad-body", InsertPoint);
CallerLPad->replaceAllUsesWith(InnerEHValuesPHI);
InnerEHValuesPHI->addIncoming(CallerLPad, OuterResumeDest);
// All done.
return InnerResumeDest;
}
/// forwardResume - Forward the 'resume' instruction to the caller's landing pad
/// block. When the landing pad block has only one predecessor, this is a simple
/// branch. When there is more than one predecessor, we need to split the
/// landing pad block after the landingpad instruction and jump to there.
void InvokeInliningInfo::forwardResume(ResumeInst *RI) {
BasicBlock *Dest = getInnerResumeDest();
BasicBlock *Src = RI->getParent();
BranchInst::Create(Dest, Src);
// Update the PHIs in the destination. They were inserted in an order which
// makes this work.
addIncomingPHIValuesForInto(Src, Dest);
InnerEHValuesPHI->addIncoming(RI->getOperand(0), Src);
RI->eraseFromParent();
}
/// HandleCallsInBlockInlinedThroughInvoke - When we inline a basic block into
/// an invoke, we have to turn all of the calls that can throw into
/// invokes. This function analyze BB to see if there are any calls, and if so,
/// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI
/// nodes in that block with the values specified in InvokeDestPHIValues.
///
/// Returns true to indicate that the next block should be skipped.
static bool HandleCallsInBlockInlinedThroughInvoke(BasicBlock *BB,
InvokeInliningInfo &Invoke) {
LandingPadInst *LPI = Invoke.getLandingPadInst();
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
Instruction *I = BBI++;
if (LandingPadInst *L = dyn_cast<LandingPadInst>(I)) {
unsigned NumClauses = LPI->getNumClauses();
L->reserveClauses(NumClauses);
for (unsigned i = 0; i != NumClauses; ++i)
L->addClause(LPI->getClause(i));
}
// We only need to check for function calls: inlined invoke
// instructions require no special handling.
CallInst *CI = dyn_cast<CallInst>(I);
// If this call cannot unwind, don't convert it to an invoke.
if (!CI || CI->doesNotThrow())
continue;
// Convert this function call into an invoke instruction. First, split the
// basic block.
BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
// Delete the unconditional branch inserted by splitBasicBlock
BB->getInstList().pop_back();
// Create the new invoke instruction.
ImmutableCallSite CS(CI);
SmallVector<Value*, 8> InvokeArgs(CS.arg_begin(), CS.arg_end());
InvokeInst *II = InvokeInst::Create(CI->getCalledValue(), Split,
Invoke.getOuterResumeDest(),
InvokeArgs, CI->getName(), BB);
II->setCallingConv(CI->getCallingConv());
II->setAttributes(CI->getAttributes());
// Make sure that anything using the call now uses the invoke! This also
// updates the CallGraph if present, because it uses a WeakVH.
CI->replaceAllUsesWith(II);
// Delete the original call
Split->getInstList().pop_front();
// Update any PHI nodes in the exceptional block to indicate that there is
// now a new entry in them.
Invoke.addIncomingPHIValuesFor(BB);
return false;
}
return false;
}
/// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls
/// in the body of the inlined function into invokes.
///
/// II is the invoke instruction being 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();
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 the code doesn't have calls or unwinds, we know there is
// nothing to rewrite.
if (!InlinedCodeInfo.ContainsCalls) {
// 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());
return;
}
InvokeInliningInfo Invoke(II);
for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E; ++BB){
if (InlinedCodeInfo.ContainsCalls)
if (HandleCallsInBlockInlinedThroughInvoke(BB, Invoke)) {
// Honor a request to skip the next block.
++BB;
continue;
}
if (ResumeInst *RI = dyn_cast<ResumeInst>(BB->getTerminator()))
Invoke.forwardResume(RI);
}
// 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 may remain.
static void UpdateCallGraphAfterInlining(CallSite CS,
Function::iterator FirstNewBlock,
ValueToValueMapTy &VMap,
InlineFunctionInfo &IFI) {
CallGraph &CG = *IFI.CG;
const Function *Caller = CS.getInstruction()->getParent()->getParent();
const Function *Callee = CS.getCalledFunction();
CallGraphNode *CalleeNode = CG[Callee];
CallGraphNode *CallerNode = CG[Caller];
// 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.
CallGraphNode::iterator I = CalleeNode->begin(), E = CalleeNode->end();
// Consider the case where CalleeNode == CallerNode.
CallGraphNode::CalledFunctionsVector CallCache;
if (CalleeNode == CallerNode) {
CallCache.assign(I, E);
I = CallCache.begin();
E = CallCache.end();
}
for (; I != E; ++I) {
const Value *OrigCall = I->first;
ValueToValueMapTy::iterator VMI = VMap.find(OrigCall);
// Only copy the edge if the call was inlined!
if (VMI == VMap.end() || VMI->second == 0)
continue;
// If the call was inlined, but then constant folded, there is no edge to
// add. Check for this case.
Instruction *NewCall = dyn_cast<Instruction>(VMI->second);
if (NewCall == 0) continue;
// Remember that this call site got inlined for the client of
// InlineFunction.
IFI.InlinedCalls.push_back(NewCall);
// It's possible that inlining the callsite will cause it to go from an
// indirect to a direct call by resolving a function pointer. If this
// happens, set the callee of the new call site to a more precise
// destination. This can also happen if the call graph node of the caller
// was just unnecessarily imprecise.
if (I->second->getFunction() == 0)
if (Function *F = CallSite(NewCall).getCalledFunction()) {
// Indirect call site resolved to direct call.
CallerNode->addCalledFunction(CallSite(NewCall), CG[F]);
continue;
}
CallerNode->addCalledFunction(CallSite(NewCall), I->second);
}
// Update the call graph by deleting the edge from Callee to Caller. We must
// do this after the loop above in case Caller and Callee are the same.
CallerNode->removeCallEdgeFor(CS);
}
/// HandleByValArgument - When inlining a call site that has a byval argument,
/// we have to make the implicit memcpy explicit by adding it.
static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
const Function *CalledFunc,
InlineFunctionInfo &IFI,
unsigned ByValAlignment) {
Type *AggTy = cast<PointerType>(Arg->getType())->getElementType();
// If the called function is readonly, then it could not mutate the caller's
// copy of the byval'd memory. In this case, it is safe to elide the copy and
// temporary.
if (CalledFunc->onlyReadsMemory()) {
// If the byval argument has a specified alignment that is greater than the
// passed in pointer, then we either have to round up the input pointer or
// give up on this transformation.
if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
return Arg;
// If the pointer is already known to be sufficiently aligned, or if we can
// round it up to a larger alignment, then we don't need a temporary.
if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
IFI.TD) >= ByValAlignment)
return Arg;
// Otherwise, we have to make a memcpy to get a safe alignment. This is bad
// for code quality, but rarely happens and is required for correctness.
}
LLVMContext &Context = Arg->getContext();
Type *VoidPtrTy = Type::getInt8PtrTy(Context);
// Create the alloca. If we have TargetData, use nice alignment.
unsigned Align = 1;
if (IFI.TD)
Align = IFI.TD->getPrefTypeAlignment(AggTy);
// If the byval had an alignment specified, we *must* use at least that
// alignment, as it is required by the byval argument (and uses of the
// pointer inside the callee).
Align = std::max(Align, ByValAlignment);
Function *Caller = TheCall->getParent()->getParent();
Value *NewAlloca = new AllocaInst(AggTy, 0, Align, Arg->getName(),
&*Caller->begin()->begin());
// Emit a memcpy.
Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
Intrinsic::memcpy,
Tys);
Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
Value *SrcCast = new BitCastInst(Arg, VoidPtrTy, "tmp", TheCall);
Value *Size;
if (IFI.TD == 0)
Size = ConstantExpr::getSizeOf(AggTy);
else
Size = ConstantInt::get(Type::getInt64Ty(Context),
IFI.TD->getTypeStoreSize(AggTy));
// Always generate a memcpy of alignment 1 here because we don't know
// the alignment of the src pointer. Other optimizations can infer
// better alignment.
Value *CallArgs[] = {
DestCast, SrcCast, Size,
ConstantInt::get(Type::getInt32Ty(Context), 1),
ConstantInt::getFalse(Context) // isVolatile
};
IRBuilder<>(TheCall).CreateCall(MemCpyFn, CallArgs);
// Uses of the argument in the function should use our new alloca
// instead.
return NewAlloca;
}
// isUsedByLifetimeMarker - Check whether this Value is used by a lifetime
// intrinsic.
static bool isUsedByLifetimeMarker(Value *V) {
for (Value::use_iterator UI = V->use_begin(), UE = V->use_end(); UI != UE;
++UI) {
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*UI)) {
switch (II->getIntrinsicID()) {
default: break;
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end:
return true;
}
}
}
return false;
}
// hasLifetimeMarkers - Check whether the given alloca already has
// lifetime.start or lifetime.end intrinsics.
static bool hasLifetimeMarkers(AllocaInst *AI) {
Type *Int8PtrTy = Type::getInt8PtrTy(AI->getType()->getContext());
if (AI->getType() == Int8PtrTy)
return isUsedByLifetimeMarker(AI);
// Do a scan to find all the casts to i8*.
for (Value::use_iterator I = AI->use_begin(), E = AI->use_end(); I != E;
++I) {
if (I->getType() != Int8PtrTy) continue;
if (I->stripPointerCasts() != AI) continue;
if (isUsedByLifetimeMarker(*I))
return true;
}
return false;
}
/// updateInlinedAtInfo - Helper function used by fixupLineNumbers to
/// recursively update InlinedAtEntry of a DebugLoc.
static DebugLoc updateInlinedAtInfo(const DebugLoc &DL,
const DebugLoc &InlinedAtDL,
LLVMContext &Ctx) {
if (MDNode *IA = DL.getInlinedAt(Ctx)) {
DebugLoc NewInlinedAtDL
= updateInlinedAtInfo(DebugLoc::getFromDILocation(IA), InlinedAtDL, Ctx);
return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx),
NewInlinedAtDL.getAsMDNode(Ctx));
}
return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx),
InlinedAtDL.getAsMDNode(Ctx));
}
/// fixupLineNumbers - Update inlined instructions' line numbers to
/// to encode location where these instructions are inlined.
static void fixupLineNumbers(Function *Fn, Function::iterator FI,
Instruction *TheCall) {
DebugLoc TheCallDL = TheCall->getDebugLoc();
if (TheCallDL.isUnknown())
return;
for (; FI != Fn->end(); ++FI) {
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
BI != BE; ++BI) {
DebugLoc DL = BI->getDebugLoc();
if (!DL.isUnknown()) {
BI->setDebugLoc(updateInlinedAtInfo(DL, TheCallDL, BI->getContext()));
if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(BI)) {
LLVMContext &Ctx = BI->getContext();
MDNode *InlinedAt = BI->getDebugLoc().getInlinedAt(Ctx);
DVI->setOperand(2, createInlinedVariable(DVI->getVariable(),
InlinedAt, Ctx));
}
}
}
}
}
/// 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
/// exists in the instruction stream. Similarly this will inline a recursive
/// function by one level.
bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
bool InsertLifetime) {
Instruction *TheCall = CS.getInstruction();
assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
"Instruction not in function!");
// If IFI has any state in it, zap it before we fill it in.
IFI.reset();
const Function *CalledFunc = CS.getCalledFunction();
if (CalledFunc == 0 || // Can't inline external function or indirect
CalledFunc->isDeclaration() || // call, or call to a vararg function!
CalledFunc->getFunctionType()->isVarArg()) return false;
// If the call to the callee is not a tail call, we must clear the 'tail'
// flags on any calls that we inline.
bool MustClearTailCallFlags =
!(isa<CallInst>(TheCall) && cast<CallInst>(TheCall)->isTailCall());
// If the call to the callee cannot throw, set the 'nounwind' flag on any
// calls that we inline.
bool MarkNoUnwind = CS.doesNotThrow();
BasicBlock *OrigBB = TheCall->getParent();
Function *Caller = OrigBB->getParent();
// 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->hasGC()) {
if (!Caller->hasGC())
Caller->setGC(CalledFunc->getGC());
else if (CalledFunc->getGC() != Caller->getGC())
return false;
}
// Get the personality function from the callee if it contains a landing pad.
Value *CalleePersonality = 0;
for (Function::const_iterator I = CalledFunc->begin(), E = CalledFunc->end();
I != E; ++I)
if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
const BasicBlock *BB = II->getUnwindDest();
const LandingPadInst *LP = BB->getLandingPadInst();
CalleePersonality = LP->getPersonalityFn();
break;
}
// Find the personality function used by the landing pads of the caller. If it
// exists, then check to see that it matches the personality function used in
// the callee.
if (CalleePersonality) {
for (Function::const_iterator I = Caller->begin(), E = Caller->end();
I != E; ++I)
if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
const BasicBlock *BB = II->getUnwindDest();
const LandingPadInst *LP = BB->getLandingPadInst();
// If the personality functions match, then we can perform the
// inlining. Otherwise, we can't inline.
// TODO: This isn't 100% true. Some personality functions are proper
// supersets of others and can be used in place of the other.
if (LP->getPersonalityFn() != CalleePersonality)
return false;
break;
}
}
// 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();
// Make sure to capture all of the return instructions from the cloned
// function.
SmallVector<ReturnInst*, 8> Returns;
ClonedCodeInfo InlinedFunctionInfo;
Function::iterator FirstNewBlock;
{ // Scope to destroy VMap after cloning.
ValueToValueMapTy VMap;
assert(CalledFunc->arg_size() == CS.arg_size() &&
"No varargs calls can be inlined!");
// Calculate the vector of arguments to pass into the function cloner, which
// matches up the formal to the actual argument values.
CallSite::arg_iterator AI = CS.arg_begin();
unsigned ArgNo = 0;
for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
Value *ActualArg = *AI;
// When byval arguments actually inlined, we need to make the copy implied
// by them explicit. However, we don't do this if the callee is readonly
// or readnone, because the copy would be unneeded: the callee doesn't
// modify the struct.
if (CS.isByValArgument(ArgNo)) {
ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
CalledFunc->getParamAlignment(ArgNo+1));
// Calls that we inline may use the new alloca, so we need to clear
// their 'tail' flags if HandleByValArgument introduced a new alloca and
// the callee has calls.
MustClearTailCallFlags |= ActualArg != *AI;
}
VMap[I] = ActualArg;
}
// 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, VMap,
/*ModuleLevelChanges=*/false, Returns, ".i",
&InlinedFunctionInfo, IFI.TD, TheCall);
// Remember the first block that is newly cloned over.
FirstNewBlock = LastBlock; ++FirstNewBlock;
// Update the callgraph if requested.
if (IFI.CG)
UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);
// Update inlined instructions' line number information.
fixupLineNumbers(Caller, FirstNewBlock, TheCall);
}
// 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.
{
BasicBlock::iterator InsertPoint = Caller->begin()->begin();
for (BasicBlock::iterator I = FirstNewBlock->begin(),
E = FirstNewBlock->end(); I != E; ) {
AllocaInst *AI = dyn_cast<AllocaInst>(I++);
if (AI == 0) continue;
// 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()))
continue;
// Keep track of the static allocas that we inline into the caller.
IFI.StaticAllocas.push_back(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())) {
IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
++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);
}
}
// Leave lifetime markers for the static alloca's, scoping them to the
// function we just inlined.
if (InsertLifetime && !IFI.StaticAllocas.empty()) {
IRBuilder<> builder(FirstNewBlock->begin());
for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
AllocaInst *AI = IFI.StaticAllocas[ai];
// If the alloca is already scoped to something smaller than the whole
// function then there's no need to add redundant, less accurate markers.
if (hasLifetimeMarkers(AI))
continue;
builder.CreateLifetimeStart(AI);
for (unsigned ri = 0, re = Returns.size(); ri != re; ++ri) {
IRBuilder<> builder(Returns[ri]);
builder.CreateLifetimeEnd(AI);
}
}
}
// 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();
// Get the two intrinsics we care about.
Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore);
// Insert the llvm.stacksave.
CallInst *SavedPtr = IRBuilder<>(FirstNewBlock, FirstNewBlock->begin())
.CreateCall(StackSave, "savedstack");
// Insert a call to llvm.stackrestore before any return instructions in the
// inlined function.
for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
IRBuilder<>(Returns[i]).CreateCall(StackRestore, SavedPtr);
}
}
// 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)) {
if (MustClearTailCallFlags)
CI->setTailCall(false);
if (MarkNoUnwind)
CI->setDoesNotThrow();
}
}
// If we are inlining for an invoke instruction, we must make sure to rewrite
// any 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))
BranchInst::Create(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()) {
ReturnInst *R = Returns[0];
if (TheCall == R->getReturnValue())
TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
else
TheCall->replaceAllUsesWith(R->getReturnValue());
}
// Since we are now done with the Call/Invoke, we can delete it.
TheCall->eraseFromParent();
// Since we are now done with the return instruction, delete it also.
Returns[0]->eraseFromParent();
// 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 = BranchInst::Create(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(),
FirstNewBlock, Caller->end());
// Handle all of the return instructions that we just cloned in, and eliminate
// any users of the original call/invoke instruction.
Type *RTy = CalledFunc->getReturnType();
PHINode *PHI = 0;
if (Returns.size() > 1) {
// The PHI node should go at the front of the new basic block to merge all
// possible incoming values.
if (!TheCall->use_empty()) {
PHI = PHINode::Create(RTy, Returns.size(), 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 adding entries to the PHI node
// as appropriate.
if (PHI) {
for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
ReturnInst *RI = Returns[i];
assert(RI->getReturnValue()->getType() == PHI->getType() &&
"Ret value not consistent in function!");
PHI->addIncoming(RI->getReturnValue(), RI->getParent());
}
}
// Add a branch to the merge points and remove return instructions.
for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
ReturnInst *RI = Returns[i];
BranchInst::Create(AfterCallBB, RI);
RI->eraseFromParent();
}
} 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()) {
if (TheCall == Returns[0]->getReturnValue())
TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
else
TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
}
// Update PHI nodes that use the ReturnBB to use the AfterCallBB.
BasicBlock *ReturnBB = Returns[0]->getParent();
ReturnBB->replaceAllUsesWith(AfterCallBB);
// Splice the code from the return block into the block that it will return
// to, which contains the code that was after the call.
AfterCallBB->getInstList().splice(AfterCallBB->begin(),
ReturnBB->getInstList());
// 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);
// Splice the code entry block into calling block, right before the
// unconditional branch.
CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes
OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());
// Remove the unconditional branch.
OrigBB->getInstList().erase(Br);
// Now we can remove the CalleeEntry block, which is now empty.
Caller->getBasicBlockList().erase(CalleeEntry);
// If we inserted a phi node, check to see if it has a single value (e.g. all
// the entries are the same or undef). If so, remove the PHI so it doesn't
// block other optimizations.
if (PHI) {
if (Value *V = SimplifyInstruction(PHI, IFI.TD)) {
PHI->replaceAllUsesWith(V);
PHI->eraseFromParent();
}
}
return true;
}
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