1 //===- InlineFunction.cpp - Code to perform function inlining -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements inlining of a function into a call site, resolving
11 // parameters and the return value as appropriate.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Transforms/Utils/Cloning.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/LLVMContext.h"
19 #include "llvm/Module.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/IntrinsicInst.h"
22 #include "llvm/Intrinsics.h"
23 #include "llvm/Attributes.h"
24 #include "llvm/Analysis/CallGraph.h"
25 #include "llvm/Analysis/DebugInfo.h"
26 #include "llvm/Target/TargetData.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include "llvm/ADT/StringExtras.h"
29 #include "llvm/Support/CallSite.h"
32 bool llvm::InlineFunction(CallInst
*CI
, CallGraph
*CG
, const TargetData
*TD
,
33 SmallVectorImpl
<AllocaInst
*> *StaticAllocas
) {
34 return InlineFunction(CallSite(CI
), CG
, TD
, StaticAllocas
);
36 bool llvm::InlineFunction(InvokeInst
*II
, CallGraph
*CG
, const TargetData
*TD
,
37 SmallVectorImpl
<AllocaInst
*> *StaticAllocas
) {
38 return InlineFunction(CallSite(II
), CG
, TD
, StaticAllocas
);
42 /// HandleCallsInBlockInlinedThroughInvoke - When we inline a basic block into
43 /// an invoke, we have to turn all of the calls that can throw into
44 /// invokes. This function analyze BB to see if there are any calls, and if so,
45 /// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI
46 /// nodes in that block with the values specified in InvokeDestPHIValues.
48 static void HandleCallsInBlockInlinedThroughInvoke(BasicBlock
*BB
,
49 BasicBlock
*InvokeDest
,
50 const SmallVectorImpl
<Value
*> &InvokeDestPHIValues
) {
51 for (BasicBlock::iterator BBI
= BB
->begin(), E
= BB
->end(); BBI
!= E
; ) {
52 Instruction
*I
= BBI
++;
54 // We only need to check for function calls: inlined invoke
55 // instructions require no special handling.
56 CallInst
*CI
= dyn_cast
<CallInst
>(I
);
57 if (CI
== 0) continue;
59 // If this call cannot unwind, don't convert it to an invoke.
60 if (CI
->doesNotThrow())
63 // Convert this function call into an invoke instruction.
64 // First, split the basic block.
65 BasicBlock
*Split
= BB
->splitBasicBlock(CI
, CI
->getName()+".noexc");
67 // Next, create the new invoke instruction, inserting it at the end
68 // of the old basic block.
69 SmallVector
<Value
*, 8> InvokeArgs(CI
->op_begin()+1, CI
->op_end());
71 InvokeInst::Create(CI
->getCalledValue(), Split
, InvokeDest
,
72 InvokeArgs
.begin(), InvokeArgs
.end(),
73 CI
->getName(), BB
->getTerminator());
74 II
->setCallingConv(CI
->getCallingConv());
75 II
->setAttributes(CI
->getAttributes());
77 // Make sure that anything using the call now uses the invoke! This also
78 // updates the CallGraph if present.
79 CI
->replaceAllUsesWith(II
);
81 // Delete the unconditional branch inserted by splitBasicBlock
82 BB
->getInstList().pop_back();
83 Split
->getInstList().pop_front(); // Delete the original call
85 // Update any PHI nodes in the exceptional block to indicate that
86 // there is now a new entry in them.
88 for (BasicBlock::iterator I
= InvokeDest
->begin();
89 isa
<PHINode
>(I
); ++I
, ++i
)
90 cast
<PHINode
>(I
)->addIncoming(InvokeDestPHIValues
[i
], BB
);
92 // This basic block is now complete, the caller will continue scanning the
99 /// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls
100 /// in the body of the inlined function into invokes and turn unwind
101 /// instructions into branches to the invoke unwind dest.
103 /// II is the invoke instruction being inlined. FirstNewBlock is the first
104 /// block of the inlined code (the last block is the end of the function),
105 /// and InlineCodeInfo is information about the code that got inlined.
106 static void HandleInlinedInvoke(InvokeInst
*II
, BasicBlock
*FirstNewBlock
,
107 ClonedCodeInfo
&InlinedCodeInfo
) {
108 BasicBlock
*InvokeDest
= II
->getUnwindDest();
109 SmallVector
<Value
*, 8> InvokeDestPHIValues
;
111 // If there are PHI nodes in the unwind destination block, we need to
112 // keep track of which values came into them from this invoke, then remove
113 // the entry for this block.
114 BasicBlock
*InvokeBlock
= II
->getParent();
115 for (BasicBlock::iterator I
= InvokeDest
->begin(); isa
<PHINode
>(I
); ++I
) {
116 PHINode
*PN
= cast
<PHINode
>(I
);
117 // Save the value to use for this edge.
118 InvokeDestPHIValues
.push_back(PN
->getIncomingValueForBlock(InvokeBlock
));
121 Function
*Caller
= FirstNewBlock
->getParent();
123 // The inlined code is currently at the end of the function, scan from the
124 // start of the inlined code to its end, checking for stuff we need to
125 // rewrite. If the code doesn't have calls or unwinds, we know there is
126 // nothing to rewrite.
127 if (!InlinedCodeInfo
.ContainsCalls
&& !InlinedCodeInfo
.ContainsUnwinds
) {
128 // Now that everything is happy, we have one final detail. The PHI nodes in
129 // the exception destination block still have entries due to the original
130 // invoke instruction. Eliminate these entries (which might even delete the
132 InvokeDest
->removePredecessor(II
->getParent());
136 for (Function::iterator BB
= FirstNewBlock
, E
= Caller
->end(); BB
!= E
; ++BB
){
137 if (InlinedCodeInfo
.ContainsCalls
)
138 HandleCallsInBlockInlinedThroughInvoke(BB
, InvokeDest
,
139 InvokeDestPHIValues
);
141 if (UnwindInst
*UI
= dyn_cast
<UnwindInst
>(BB
->getTerminator())) {
142 // An UnwindInst requires special handling when it gets inlined into an
143 // invoke site. Once this happens, we know that the unwind would cause
144 // a control transfer to the invoke exception destination, so we can
145 // transform it into a direct branch to the exception destination.
146 BranchInst::Create(InvokeDest
, UI
);
148 // Delete the unwind instruction!
149 UI
->eraseFromParent();
151 // Update any PHI nodes in the exceptional block to indicate that
152 // there is now a new entry in them.
154 for (BasicBlock::iterator I
= InvokeDest
->begin();
155 isa
<PHINode
>(I
); ++I
, ++i
) {
156 PHINode
*PN
= cast
<PHINode
>(I
);
157 PN
->addIncoming(InvokeDestPHIValues
[i
], BB
);
162 // Now that everything is happy, we have one final detail. The PHI nodes in
163 // the exception destination block still have entries due to the original
164 // invoke instruction. Eliminate these entries (which might even delete the
166 InvokeDest
->removePredecessor(II
->getParent());
169 /// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
170 /// into the caller, update the specified callgraph to reflect the changes we
171 /// made. Note that it's possible that not all code was copied over, so only
172 /// some edges of the callgraph may remain.
173 static void UpdateCallGraphAfterInlining(CallSite CS
,
174 Function::iterator FirstNewBlock
,
175 DenseMap
<const Value
*, Value
*> &ValueMap
,
177 const Function
*Caller
= CS
.getInstruction()->getParent()->getParent();
178 const Function
*Callee
= CS
.getCalledFunction();
179 CallGraphNode
*CalleeNode
= CG
[Callee
];
180 CallGraphNode
*CallerNode
= CG
[Caller
];
182 // Since we inlined some uninlined call sites in the callee into the caller,
183 // add edges from the caller to all of the callees of the callee.
184 CallGraphNode::iterator I
= CalleeNode
->begin(), E
= CalleeNode
->end();
186 // Consider the case where CalleeNode == CallerNode.
187 CallGraphNode::CalledFunctionsVector CallCache
;
188 if (CalleeNode
== CallerNode
) {
189 CallCache
.assign(I
, E
);
190 I
= CallCache
.begin();
194 for (; I
!= E
; ++I
) {
195 const Value
*OrigCall
= I
->first
;
197 DenseMap
<const Value
*, Value
*>::iterator VMI
= ValueMap
.find(OrigCall
);
198 // Only copy the edge if the call was inlined!
199 if (VMI
== ValueMap
.end() || VMI
->second
== 0)
202 // If the call was inlined, but then constant folded, there is no edge to
203 // add. Check for this case.
204 if (Instruction
*NewCall
= dyn_cast
<Instruction
>(VMI
->second
))
205 CallerNode
->addCalledFunction(CallSite::get(NewCall
), I
->second
);
208 // Update the call graph by deleting the edge from Callee to Caller. We must
209 // do this after the loop above in case Caller and Callee are the same.
210 CallerNode
->removeCallEdgeFor(CS
);
213 /// findFnRegionEndMarker - This is a utility routine that is used by
214 /// InlineFunction. Return llvm.dbg.region.end intrinsic that corresponds
215 /// to the llvm.dbg.func.start of the function F. Otherwise return NULL.
217 static const DbgRegionEndInst
*findFnRegionEndMarker(const Function
*F
) {
219 MDNode
*FnStart
= NULL
;
220 const DbgRegionEndInst
*FnEnd
= NULL
;
221 for (Function::const_iterator FI
= F
->begin(), FE
=F
->end(); FI
!= FE
; ++FI
)
222 for (BasicBlock::const_iterator BI
= FI
->begin(), BE
= FI
->end(); BI
!= BE
;
224 if (FnStart
== NULL
) {
225 if (const DbgFuncStartInst
*FSI
= dyn_cast
<DbgFuncStartInst
>(BI
)) {
226 DISubprogram
SP(FSI
->getSubprogram());
227 assert (SP
.isNull() == false && "Invalid llvm.dbg.func.start");
229 FnStart
= SP
.getNode();
234 if (const DbgRegionEndInst
*REI
= dyn_cast
<DbgRegionEndInst
>(BI
))
235 if (REI
->getContext() == FnStart
)
241 // InlineFunction - This function inlines the called function into the basic
242 // block of the caller. This returns false if it is not possible to inline this
243 // call. The program is still in a well defined state if this occurs though.
245 // Note that this only does one level of inlining. For example, if the
246 // instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
247 // exists in the instruction stream. Similiarly this will inline a recursive
248 // function by one level.
250 bool llvm::InlineFunction(CallSite CS
, CallGraph
*CG
, const TargetData
*TD
,
251 SmallVectorImpl
<AllocaInst
*> *StaticAllocas
) {
252 Instruction
*TheCall
= CS
.getInstruction();
253 LLVMContext
&Context
= TheCall
->getContext();
254 assert(TheCall
->getParent() && TheCall
->getParent()->getParent() &&
255 "Instruction not in function!");
257 const Function
*CalledFunc
= CS
.getCalledFunction();
258 if (CalledFunc
== 0 || // Can't inline external function or indirect
259 CalledFunc
->isDeclaration() || // call, or call to a vararg function!
260 CalledFunc
->getFunctionType()->isVarArg()) return false;
263 // If the call to the callee is not a tail call, we must clear the 'tail'
264 // flags on any calls that we inline.
265 bool MustClearTailCallFlags
=
266 !(isa
<CallInst
>(TheCall
) && cast
<CallInst
>(TheCall
)->isTailCall());
268 // If the call to the callee cannot throw, set the 'nounwind' flag on any
269 // calls that we inline.
270 bool MarkNoUnwind
= CS
.doesNotThrow();
272 BasicBlock
*OrigBB
= TheCall
->getParent();
273 Function
*Caller
= OrigBB
->getParent();
275 // GC poses two hazards to inlining, which only occur when the callee has GC:
276 // 1. If the caller has no GC, then the callee's GC must be propagated to the
278 // 2. If the caller has a differing GC, it is invalid to inline.
279 if (CalledFunc
->hasGC()) {
280 if (!Caller
->hasGC())
281 Caller
->setGC(CalledFunc
->getGC());
282 else if (CalledFunc
->getGC() != Caller
->getGC())
286 // Get an iterator to the last basic block in the function, which will have
287 // the new function inlined after it.
289 Function::iterator LastBlock
= &Caller
->back();
291 // Make sure to capture all of the return instructions from the cloned
293 SmallVector
<ReturnInst
*, 8> Returns
;
294 ClonedCodeInfo InlinedFunctionInfo
;
295 Function::iterator FirstNewBlock
;
297 { // Scope to destroy ValueMap after cloning.
298 DenseMap
<const Value
*, Value
*> ValueMap
;
300 assert(CalledFunc
->arg_size() == CS
.arg_size() &&
301 "No varargs calls can be inlined!");
303 // Calculate the vector of arguments to pass into the function cloner, which
304 // matches up the formal to the actual argument values.
305 CallSite::arg_iterator AI
= CS
.arg_begin();
307 for (Function::const_arg_iterator I
= CalledFunc
->arg_begin(),
308 E
= CalledFunc
->arg_end(); I
!= E
; ++I
, ++AI
, ++ArgNo
) {
309 Value
*ActualArg
= *AI
;
311 // When byval arguments actually inlined, we need to make the copy implied
312 // by them explicit. However, we don't do this if the callee is readonly
313 // or readnone, because the copy would be unneeded: the callee doesn't
314 // modify the struct.
315 if (CalledFunc
->paramHasAttr(ArgNo
+1, Attribute::ByVal
) &&
316 !CalledFunc
->onlyReadsMemory()) {
317 const Type
*AggTy
= cast
<PointerType
>(I
->getType())->getElementType();
318 const Type
*VoidPtrTy
=
319 PointerType::getUnqual(Type::getInt8Ty(Context
));
321 // Create the alloca. If we have TargetData, use nice alignment.
323 if (TD
) Align
= TD
->getPrefTypeAlignment(AggTy
);
324 Value
*NewAlloca
= new AllocaInst(AggTy
, 0, Align
,
326 &*Caller
->begin()->begin());
328 const Type
*Tys
[] = { Type::getInt64Ty(Context
) };
329 Function
*MemCpyFn
= Intrinsic::getDeclaration(Caller
->getParent(),
332 Value
*DestCast
= new BitCastInst(NewAlloca
, VoidPtrTy
, "tmp", TheCall
);
333 Value
*SrcCast
= new BitCastInst(*AI
, VoidPtrTy
, "tmp", TheCall
);
337 Size
= ConstantExpr::getSizeOf(AggTy
);
339 Size
= ConstantInt::get(Type::getInt64Ty(Context
),
340 TD
->getTypeStoreSize(AggTy
));
342 // Always generate a memcpy of alignment 1 here because we don't know
343 // the alignment of the src pointer. Other optimizations can infer
345 Value
*CallArgs
[] = {
346 DestCast
, SrcCast
, Size
,
347 ConstantInt::get(Type::getInt32Ty(Context
), 1)
349 CallInst
*TheMemCpy
=
350 CallInst::Create(MemCpyFn
, CallArgs
, CallArgs
+4, "", TheCall
);
352 // If we have a call graph, update it.
354 CallGraphNode
*MemCpyCGN
= CG
->getOrInsertFunction(MemCpyFn
);
355 CallGraphNode
*CallerNode
= (*CG
)[Caller
];
356 CallerNode
->addCalledFunction(TheMemCpy
, MemCpyCGN
);
359 // Uses of the argument in the function should use our new alloca
361 ActualArg
= NewAlloca
;
364 ValueMap
[I
] = ActualArg
;
367 // Adjust llvm.dbg.region.end. If the CalledFunc has region end
368 // marker then clone that marker after next stop point at the
369 // call site. The function body cloner does not clone original
370 // region end marker from the CalledFunc. This will ensure that
371 // inlined function's scope ends at the right place.
372 if (const DbgRegionEndInst
*DREI
= findFnRegionEndMarker(CalledFunc
)) {
373 for (BasicBlock::iterator BI
= TheCall
, BE
= TheCall
->getParent()->end();
375 if (DbgStopPointInst
*DSPI
= dyn_cast
<DbgStopPointInst
>(BI
)) {
376 if (DbgRegionEndInst
*NewDREI
=
377 dyn_cast
<DbgRegionEndInst
>(DREI
->clone(Context
)))
378 NewDREI
->insertAfter(DSPI
);
384 // We want the inliner to prune the code as it copies. We would LOVE to
385 // have no dead or constant instructions leftover after inlining occurs
386 // (which can happen, e.g., because an argument was constant), but we'll be
387 // happy with whatever the cloner can do.
388 CloneAndPruneFunctionInto(Caller
, CalledFunc
, ValueMap
, Returns
, ".i",
389 &InlinedFunctionInfo
, TD
);
391 // Remember the first block that is newly cloned over.
392 FirstNewBlock
= LastBlock
; ++FirstNewBlock
;
394 // Update the callgraph if requested.
396 UpdateCallGraphAfterInlining(CS
, FirstNewBlock
, ValueMap
, *CG
);
399 // If there are any alloca instructions in the block that used to be the entry
400 // block for the callee, move them to the entry block of the caller. First
401 // calculate which instruction they should be inserted before. We insert the
402 // instructions at the end of the current alloca list.
405 BasicBlock::iterator InsertPoint
= Caller
->begin()->begin();
406 for (BasicBlock::iterator I
= FirstNewBlock
->begin(),
407 E
= FirstNewBlock
->end(); I
!= E
; ) {
408 AllocaInst
*AI
= dyn_cast
<AllocaInst
>(I
++);
409 if (AI
== 0) continue;
411 // If the alloca is now dead, remove it. This often occurs due to code
413 if (AI
->use_empty()) {
414 AI
->eraseFromParent();
418 if (!isa
<Constant
>(AI
->getArraySize()))
421 // Keep track of the static allocas that we inline into the caller if the
422 // StaticAllocas pointer is non-null.
423 if (StaticAllocas
) StaticAllocas
->push_back(AI
);
425 // Scan for the block of allocas that we can move over, and move them
427 while (isa
<AllocaInst
>(I
) &&
428 isa
<Constant
>(cast
<AllocaInst
>(I
)->getArraySize())) {
429 if (StaticAllocas
) StaticAllocas
->push_back(cast
<AllocaInst
>(I
));
433 // Transfer all of the allocas over in a block. Using splice means
434 // that the instructions aren't removed from the symbol table, then
436 Caller
->getEntryBlock().getInstList().splice(InsertPoint
,
437 FirstNewBlock
->getInstList(),
442 // If the inlined code contained dynamic alloca instructions, wrap the inlined
443 // code with llvm.stacksave/llvm.stackrestore intrinsics.
444 if (InlinedFunctionInfo
.ContainsDynamicAllocas
) {
445 Module
*M
= Caller
->getParent();
446 // Get the two intrinsics we care about.
447 Constant
*StackSave
, *StackRestore
;
448 StackSave
= Intrinsic::getDeclaration(M
, Intrinsic::stacksave
);
449 StackRestore
= Intrinsic::getDeclaration(M
, Intrinsic::stackrestore
);
451 // If we are preserving the callgraph, add edges to the stacksave/restore
452 // functions for the calls we insert.
453 CallGraphNode
*StackSaveCGN
= 0, *StackRestoreCGN
= 0, *CallerNode
= 0;
455 // We know that StackSave/StackRestore are Function*'s, because they are
456 // intrinsics which must have the right types.
457 StackSaveCGN
= CG
->getOrInsertFunction(cast
<Function
>(StackSave
));
458 StackRestoreCGN
= CG
->getOrInsertFunction(cast
<Function
>(StackRestore
));
459 CallerNode
= (*CG
)[Caller
];
462 // Insert the llvm.stacksave.
463 CallInst
*SavedPtr
= CallInst::Create(StackSave
, "savedstack",
464 FirstNewBlock
->begin());
465 if (CG
) CallerNode
->addCalledFunction(SavedPtr
, StackSaveCGN
);
467 // Insert a call to llvm.stackrestore before any return instructions in the
469 for (unsigned i
= 0, e
= Returns
.size(); i
!= e
; ++i
) {
470 CallInst
*CI
= CallInst::Create(StackRestore
, SavedPtr
, "", Returns
[i
]);
471 if (CG
) CallerNode
->addCalledFunction(CI
, StackRestoreCGN
);
474 // Count the number of StackRestore calls we insert.
475 unsigned NumStackRestores
= Returns
.size();
477 // If we are inlining an invoke instruction, insert restores before each
478 // unwind. These unwinds will be rewritten into branches later.
479 if (InlinedFunctionInfo
.ContainsUnwinds
&& isa
<InvokeInst
>(TheCall
)) {
480 for (Function::iterator BB
= FirstNewBlock
, E
= Caller
->end();
482 if (UnwindInst
*UI
= dyn_cast
<UnwindInst
>(BB
->getTerminator())) {
483 CallInst::Create(StackRestore
, SavedPtr
, "", UI
);
489 // If we are inlining tail call instruction through a call site that isn't
490 // marked 'tail', we must remove the tail marker for any calls in the inlined
491 // code. Also, calls inlined through a 'nounwind' call site should be marked
493 if (InlinedFunctionInfo
.ContainsCalls
&&
494 (MustClearTailCallFlags
|| MarkNoUnwind
)) {
495 for (Function::iterator BB
= FirstNewBlock
, E
= Caller
->end();
497 for (BasicBlock::iterator I
= BB
->begin(), E
= BB
->end(); I
!= E
; ++I
)
498 if (CallInst
*CI
= dyn_cast
<CallInst
>(I
)) {
499 if (MustClearTailCallFlags
)
500 CI
->setTailCall(false);
502 CI
->setDoesNotThrow();
506 // If we are inlining through a 'nounwind' call site then any inlined 'unwind'
507 // instructions are unreachable.
508 if (InlinedFunctionInfo
.ContainsUnwinds
&& MarkNoUnwind
)
509 for (Function::iterator BB
= FirstNewBlock
, E
= Caller
->end();
511 TerminatorInst
*Term
= BB
->getTerminator();
512 if (isa
<UnwindInst
>(Term
)) {
513 new UnreachableInst(Context
, Term
);
514 BB
->getInstList().erase(Term
);
518 // If we are inlining for an invoke instruction, we must make sure to rewrite
519 // any inlined 'unwind' instructions into branches to the invoke exception
520 // destination, and call instructions into invoke instructions.
521 if (InvokeInst
*II
= dyn_cast
<InvokeInst
>(TheCall
))
522 HandleInlinedInvoke(II
, FirstNewBlock
, InlinedFunctionInfo
);
524 // If we cloned in _exactly one_ basic block, and if that block ends in a
525 // return instruction, we splice the body of the inlined callee directly into
526 // the calling basic block.
527 if (Returns
.size() == 1 && std::distance(FirstNewBlock
, Caller
->end()) == 1) {
528 // Move all of the instructions right before the call.
529 OrigBB
->getInstList().splice(TheCall
, FirstNewBlock
->getInstList(),
530 FirstNewBlock
->begin(), FirstNewBlock
->end());
531 // Remove the cloned basic block.
532 Caller
->getBasicBlockList().pop_back();
534 // If the call site was an invoke instruction, add a branch to the normal
536 if (InvokeInst
*II
= dyn_cast
<InvokeInst
>(TheCall
))
537 BranchInst::Create(II
->getNormalDest(), TheCall
);
539 // If the return instruction returned a value, replace uses of the call with
540 // uses of the returned value.
541 if (!TheCall
->use_empty()) {
542 ReturnInst
*R
= Returns
[0];
543 if (TheCall
== R
->getReturnValue())
544 TheCall
->replaceAllUsesWith(UndefValue::get(TheCall
->getType()));
546 TheCall
->replaceAllUsesWith(R
->getReturnValue());
548 // Since we are now done with the Call/Invoke, we can delete it.
549 TheCall
->eraseFromParent();
551 // Since we are now done with the return instruction, delete it also.
552 Returns
[0]->eraseFromParent();
554 // We are now done with the inlining.
558 // Otherwise, we have the normal case, of more than one block to inline or
559 // multiple return sites.
561 // We want to clone the entire callee function into the hole between the
562 // "starter" and "ender" blocks. How we accomplish this depends on whether
563 // this is an invoke instruction or a call instruction.
564 BasicBlock
*AfterCallBB
;
565 if (InvokeInst
*II
= dyn_cast
<InvokeInst
>(TheCall
)) {
567 // Add an unconditional branch to make this look like the CallInst case...
568 BranchInst
*NewBr
= BranchInst::Create(II
->getNormalDest(), TheCall
);
570 // Split the basic block. This guarantees that no PHI nodes will have to be
571 // updated due to new incoming edges, and make the invoke case more
572 // symmetric to the call case.
573 AfterCallBB
= OrigBB
->splitBasicBlock(NewBr
,
574 CalledFunc
->getName()+".exit");
576 } else { // It's a call
577 // If this is a call instruction, we need to split the basic block that
578 // the call lives in.
580 AfterCallBB
= OrigBB
->splitBasicBlock(TheCall
,
581 CalledFunc
->getName()+".exit");
584 // Change the branch that used to go to AfterCallBB to branch to the first
585 // basic block of the inlined function.
587 TerminatorInst
*Br
= OrigBB
->getTerminator();
588 assert(Br
&& Br
->getOpcode() == Instruction::Br
&&
589 "splitBasicBlock broken!");
590 Br
->setOperand(0, FirstNewBlock
);
593 // Now that the function is correct, make it a little bit nicer. In
594 // particular, move the basic blocks inserted from the end of the function
595 // into the space made by splitting the source basic block.
596 Caller
->getBasicBlockList().splice(AfterCallBB
, Caller
->getBasicBlockList(),
597 FirstNewBlock
, Caller
->end());
599 // Handle all of the return instructions that we just cloned in, and eliminate
600 // any users of the original call/invoke instruction.
601 const Type
*RTy
= CalledFunc
->getReturnType();
603 if (Returns
.size() > 1) {
604 // The PHI node should go at the front of the new basic block to merge all
605 // possible incoming values.
607 if (!TheCall
->use_empty()) {
608 PHI
= PHINode::Create(RTy
, TheCall
->getName(),
609 AfterCallBB
->begin());
610 // Anything that used the result of the function call should now use the
611 // PHI node as their operand.
612 TheCall
->replaceAllUsesWith(PHI
);
615 // Loop over all of the return instructions adding entries to the PHI node
618 for (unsigned i
= 0, e
= Returns
.size(); i
!= e
; ++i
) {
619 ReturnInst
*RI
= Returns
[i
];
620 assert(RI
->getReturnValue()->getType() == PHI
->getType() &&
621 "Ret value not consistent in function!");
622 PHI
->addIncoming(RI
->getReturnValue(), RI
->getParent());
626 // Add a branch to the merge points and remove return instructions.
627 for (unsigned i
= 0, e
= Returns
.size(); i
!= e
; ++i
) {
628 ReturnInst
*RI
= Returns
[i
];
629 BranchInst::Create(AfterCallBB
, RI
);
630 RI
->eraseFromParent();
632 } else if (!Returns
.empty()) {
633 // Otherwise, if there is exactly one return value, just replace anything
634 // using the return value of the call with the computed value.
635 if (!TheCall
->use_empty()) {
636 if (TheCall
== Returns
[0]->getReturnValue())
637 TheCall
->replaceAllUsesWith(UndefValue::get(TheCall
->getType()));
639 TheCall
->replaceAllUsesWith(Returns
[0]->getReturnValue());
642 // Splice the code from the return block into the block that it will return
643 // to, which contains the code that was after the call.
644 BasicBlock
*ReturnBB
= Returns
[0]->getParent();
645 AfterCallBB
->getInstList().splice(AfterCallBB
->begin(),
646 ReturnBB
->getInstList());
648 // Update PHI nodes that use the ReturnBB to use the AfterCallBB.
649 ReturnBB
->replaceAllUsesWith(AfterCallBB
);
651 // Delete the return instruction now and empty ReturnBB now.
652 Returns
[0]->eraseFromParent();
653 ReturnBB
->eraseFromParent();
654 } else if (!TheCall
->use_empty()) {
655 // No returns, but something is using the return value of the call. Just
657 TheCall
->replaceAllUsesWith(UndefValue::get(TheCall
->getType()));
660 // Since we are now done with the Call/Invoke, we can delete it.
661 TheCall
->eraseFromParent();
663 // We should always be able to fold the entry block of the function into the
664 // single predecessor of the block...
665 assert(cast
<BranchInst
>(Br
)->isUnconditional() && "splitBasicBlock broken!");
666 BasicBlock
*CalleeEntry
= cast
<BranchInst
>(Br
)->getSuccessor(0);
668 // Splice the code entry block into calling block, right before the
669 // unconditional branch.
670 OrigBB
->getInstList().splice(Br
, CalleeEntry
->getInstList());
671 CalleeEntry
->replaceAllUsesWith(OrigBB
); // Update PHI nodes
673 // Remove the unconditional branch.
674 OrigBB
->getInstList().erase(Br
);
676 // Now we can remove the CalleeEntry block, which is now empty.
677 Caller
->getBasicBlockList().erase(CalleeEntry
);