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Chris Lattner8bce9882002-11-19 22:04:49 +00001//===- CloneFunction.cpp - Clone a function into another function ---------===//
Misha Brukmanb1c93172005-04-21 23:48:37 +00002//
John Criswell482202a2003-10-20 19:43:21 +00003// The LLVM Compiler Infrastructure
4//
Chris Lattnerf3ebc3f2007-12-29 20:36:04 +00005// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
Misha Brukmanb1c93172005-04-21 23:48:37 +00007//
John Criswell482202a2003-10-20 19:43:21 +00008//===----------------------------------------------------------------------===//
Chris Lattner8bce9882002-11-19 22:04:49 +00009//
10// This file implements the CloneFunctionInto interface, which is used as the
11// low-level function cloner. This is used by the CloneFunction and function
12// inliner to do the dirty work of copying the body of a function around.
13//
14//===----------------------------------------------------------------------===//
Chris Lattner16bfdb52002-03-29 19:03:54 +000015
Chris Lattner16667512002-11-19 20:59:41 +000016#include "llvm/Transforms/Utils/Cloning.h"
Chandler Carruthed0881b2012-12-03 16:50:05 +000017#include "llvm/ADT/SmallVector.h"
18#include "llvm/Analysis/ConstantFolding.h"
19#include "llvm/Analysis/InstructionSimplify.h"
Chandler Carruth1305dc32014-03-04 11:45:46 +000020#include "llvm/IR/CFG.h"
Chandler Carruth9fb823b2013-01-02 11:36:10 +000021#include "llvm/IR/Constants.h"
Chandler Carruth9a4c9e52014-03-06 00:46:21 +000022#include "llvm/IR/DebugInfo.h"
Chandler Carruth9fb823b2013-01-02 11:36:10 +000023#include "llvm/IR/DerivedTypes.h"
24#include "llvm/IR/Function.h"
25#include "llvm/IR/GlobalVariable.h"
26#include "llvm/IR/Instructions.h"
27#include "llvm/IR/IntrinsicInst.h"
28#include "llvm/IR/LLVMContext.h"
29#include "llvm/IR/Metadata.h"
Alon Mishne07d949f2014-03-12 14:42:51 +000030#include "llvm/IR/Module.h"
Chandler Carruth772c88b2012-03-28 08:38:27 +000031#include "llvm/Transforms/Utils/BasicBlockUtils.h"
32#include "llvm/Transforms/Utils/Local.h"
Dan Gohmana2095032010-08-24 18:50:07 +000033#include "llvm/Transforms/Utils/ValueMapper.h"
Chris Lattner1bfc7ab2007-02-03 00:08:31 +000034#include <map>
Chris Lattnerdf3c3422004-01-09 06:12:26 +000035using namespace llvm;
Brian Gaeke960707c2003-11-11 22:41:34 +000036
Sanjay Patelabf70232015-03-10 18:41:22 +000037/// See comments in Cloning.h.
Chris Lattnerdf3c3422004-01-09 06:12:26 +000038BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
Devang Pateld8dedee2010-06-24 00:00:42 +000039 ValueToValueMapTy &VMap,
Benjamin Kramer1266d462010-01-27 19:58:47 +000040 const Twine &NameSuffix, Function *F,
Chris Lattneredad1282006-01-13 18:39:17 +000041 ClonedCodeInfo *CodeInfo) {
Owen Anderson55f1c092009-08-13 21:58:54 +000042 BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
Chris Lattnere9f42322003-04-18 03:50:09 +000043 if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
44
Chris Lattneredad1282006-01-13 18:39:17 +000045 bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
46
47 // Loop over all instructions, and copy them over.
Chris Lattnere9f42322003-04-18 03:50:09 +000048 for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
49 II != IE; ++II) {
Nick Lewycky42fb7452009-09-27 07:38:41 +000050 Instruction *NewInst = II->clone();
Chris Lattnere9f42322003-04-18 03:50:09 +000051 if (II->hasName())
52 NewInst->setName(II->getName()+NameSuffix);
53 NewBB->getInstList().push_back(NewInst);
Devang Patelb8f11de2010-06-23 23:55:51 +000054 VMap[II] = NewInst; // Add instruction map to value.
Chris Lattneredad1282006-01-13 18:39:17 +000055
Dale Johannesen900aaa32009-03-10 22:20:02 +000056 hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
Chris Lattneredad1282006-01-13 18:39:17 +000057 if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
58 if (isa<ConstantInt>(AI->getArraySize()))
59 hasStaticAllocas = true;
60 else
61 hasDynamicAllocas = true;
62 }
63 }
64
65 if (CodeInfo) {
66 CodeInfo->ContainsCalls |= hasCalls;
Chris Lattneredad1282006-01-13 18:39:17 +000067 CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
68 CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
Dan Gohmandcb291f2007-03-22 16:38:57 +000069 BB != &BB->getParent()->getEntryBlock();
Chris Lattnere9f42322003-04-18 03:50:09 +000070 }
71 return NewBB;
72}
73
Chris Lattner16bfdb52002-03-29 19:03:54 +000074// Clone OldFunc into NewFunc, transforming the old arguments into references to
Dan Gohmanca26f792010-08-26 15:41:53 +000075// VMap values.
Chris Lattner16bfdb52002-03-29 19:03:54 +000076//
Chris Lattnerdf3c3422004-01-09 06:12:26 +000077void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
Devang Pateld8dedee2010-06-24 00:00:42 +000078 ValueToValueMapTy &VMap,
Dan Gohmanca26f792010-08-26 15:41:53 +000079 bool ModuleLevelChanges,
Chris Lattnerd84dbb32009-08-27 04:02:30 +000080 SmallVectorImpl<ReturnInst*> &Returns,
Mon P Wang5d44a432011-12-23 02:18:32 +000081 const char *NameSuffix, ClonedCodeInfo *CodeInfo,
James Molloyf6f121e2013-05-28 15:17:05 +000082 ValueMapTypeRemapper *TypeMapper,
83 ValueMaterializer *Materializer) {
Chris Lattnerb1120052002-11-19 21:54:07 +000084 assert(NameSuffix && "NameSuffix cannot be null!");
Misha Brukmanb1c93172005-04-21 23:48:37 +000085
Chris Lattnerc3626182002-11-19 22:54:01 +000086#ifndef NDEBUG
Chris Lattneredad1282006-01-13 18:39:17 +000087 for (Function::const_arg_iterator I = OldFunc->arg_begin(),
88 E = OldFunc->arg_end(); I != E; ++I)
Devang Patelb8f11de2010-06-23 23:55:51 +000089 assert(VMap.count(I) && "No mapping from source argument specified!");
Chris Lattnerc3626182002-11-19 22:54:01 +000090#endif
Chris Lattner16bfdb52002-03-29 19:03:54 +000091
Reid Kleckner23798a92014-03-26 22:26:35 +000092 // Copy all attributes other than those stored in the AttributeSet. We need
93 // to remap the parameter indices of the AttributeSet.
94 AttributeSet NewAttrs = NewFunc->getAttributes();
95 NewFunc->copyAttributesFrom(OldFunc);
96 NewFunc->setAttributes(NewAttrs);
97
Joey Gouly81259292013-04-10 10:37:38 +000098 AttributeSet OldAttrs = OldFunc->getAttributes();
99 // Clone any argument attributes that are present in the VMap.
Reid Kleckner23798a92014-03-26 22:26:35 +0000100 for (const Argument &OldArg : OldFunc->args())
101 if (Argument *NewArg = dyn_cast<Argument>(VMap[&OldArg])) {
Joey Gouly81259292013-04-10 10:37:38 +0000102 AttributeSet attrs =
Reid Kleckner23798a92014-03-26 22:26:35 +0000103 OldAttrs.getParamAttributes(OldArg.getArgNo() + 1);
Joey Gouly81259292013-04-10 10:37:38 +0000104 if (attrs.getNumSlots() > 0)
Reid Kleckner23798a92014-03-26 22:26:35 +0000105 NewArg->addAttr(attrs);
Joey Gouly81259292013-04-10 10:37:38 +0000106 }
Andrew Lenharth5aa1cc42008-10-07 18:08:38 +0000107
Reid Kleckner23798a92014-03-26 22:26:35 +0000108 NewFunc->setAttributes(
109 NewFunc->getAttributes()
110 .addAttributes(NewFunc->getContext(), AttributeSet::ReturnIndex,
111 OldAttrs.getRetAttributes())
112 .addAttributes(NewFunc->getContext(), AttributeSet::FunctionIndex,
113 OldAttrs.getFnAttributes()));
Anton Korobeynikovd38b3fb2008-03-23 16:03:00 +0000114
Chris Lattner16bfdb52002-03-29 19:03:54 +0000115 // Loop over all of the basic blocks in the function, cloning them as
Chris Lattnerb1120052002-11-19 21:54:07 +0000116 // appropriate. Note that we save BE this way in order to handle cloning of
117 // recursive functions into themselves.
Chris Lattner16bfdb52002-03-29 19:03:54 +0000118 //
119 for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
120 BI != BE; ++BI) {
Chris Lattnerfda72b12002-06-25 16:12:52 +0000121 const BasicBlock &BB = *BI;
Misha Brukmanb1c93172005-04-21 23:48:37 +0000122
Chris Lattnere9f42322003-04-18 03:50:09 +0000123 // Create a new basic block and copy instructions into it!
Chris Lattner43f8d162011-01-08 08:15:20 +0000124 BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo);
Chris Lattner16bfdb52002-03-29 19:03:54 +0000125
Eli Friedman688db1d2011-10-21 20:45:19 +0000126 // Add basic block mapping.
127 VMap[&BB] = CBB;
128
129 // It is only legal to clone a function if a block address within that
130 // function is never referenced outside of the function. Given that, we
131 // want to map block addresses from the old function to block addresses in
132 // the clone. (This is different from the generic ValueMapper
133 // implementation, which generates an invalid blockaddress when
134 // cloning a function.)
135 if (BB.hasAddressTaken()) {
136 Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
137 const_cast<BasicBlock*>(&BB));
138 VMap[OldBBAddr] = BlockAddress::get(NewFunc, CBB);
139 }
140
141 // Note return instructions for the caller.
Chris Lattnerb1120052002-11-19 21:54:07 +0000142 if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
143 Returns.push_back(RI);
Chris Lattner16bfdb52002-03-29 19:03:54 +0000144 }
145
Misha Brukmanb1c93172005-04-21 23:48:37 +0000146 // Loop over all of the instructions in the function, fixing up operand
Devang Patelb8f11de2010-06-23 23:55:51 +0000147 // references as we go. This uses VMap to do all the hard work.
Devang Patelb8f11de2010-06-23 23:55:51 +0000148 for (Function::iterator BB = cast<BasicBlock>(VMap[OldFunc->begin()]),
Nick Lewycky4d43d3c2008-04-25 16:53:59 +0000149 BE = NewFunc->end(); BB != BE; ++BB)
Chris Lattner16bfdb52002-03-29 19:03:54 +0000150 // Loop over all instructions, fixing each one as we find it...
Chris Lattner39ad6f22004-02-04 21:44:26 +0000151 for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II)
Chris Lattner43f8d162011-01-08 08:15:20 +0000152 RemapInstruction(II, VMap,
Mon P Wang5d44a432011-12-23 02:18:32 +0000153 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
James Molloyf6f121e2013-05-28 15:17:05 +0000154 TypeMapper, Materializer);
Chris Lattner16bfdb52002-03-29 19:03:54 +0000155}
Chris Lattnerfb311d22002-11-19 23:12:22 +0000156
Alon Mishne07d949f2014-03-12 14:42:51 +0000157// Find the MDNode which corresponds to the DISubprogram data that described F.
158static MDNode* FindSubprogram(const Function *F, DebugInfoFinder &Finder) {
Alon Mishnead312152014-03-18 09:41:07 +0000159 for (DISubprogram Subprogram : Finder.subprograms()) {
Alon Mishne07d949f2014-03-12 14:42:51 +0000160 if (Subprogram.describes(F)) return Subprogram;
161 }
Craig Topperf40110f2014-04-25 05:29:35 +0000162 return nullptr;
Alon Mishne07d949f2014-03-12 14:42:51 +0000163}
164
165// Add an operand to an existing MDNode. The new operand will be added at the
166// back of the operand list.
Duncan P. N. Exon Smith5bf8fef2014-12-09 18:38:53 +0000167static void AddOperand(DICompileUnit CU, DIArray SPs, Metadata *NewSP) {
168 SmallVector<Metadata *, 16> NewSPs;
Duncan P. N. Exon Smithb2362112014-12-06 00:48:17 +0000169 NewSPs.reserve(SPs->getNumOperands() + 1);
170 for (unsigned I = 0, E = SPs->getNumOperands(); I != E; ++I)
171 NewSPs.push_back(SPs->getOperand(I));
172 NewSPs.push_back(NewSP);
173 CU.replaceSubprograms(DIArray(MDNode::get(CU->getContext(), NewSPs)));
Alon Mishne07d949f2014-03-12 14:42:51 +0000174}
175
176// Clone the module-level debug info associated with OldFunc. The cloned data
177// will point to NewFunc instead.
178static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
179 ValueToValueMapTy &VMap) {
180 DebugInfoFinder Finder;
181 Finder.processModule(*OldFunc->getParent());
182
183 const MDNode *OldSubprogramMDNode = FindSubprogram(OldFunc, Finder);
184 if (!OldSubprogramMDNode) return;
185
186 // Ensure that OldFunc appears in the map.
187 // (if it's already there it must point to NewFunc anyway)
188 VMap[OldFunc] = NewFunc;
Duncan P. N. Exon Smith6186fb22015-04-06 23:27:00 +0000189 DISubprogram NewSubprogram =
190 cast<MDSubprogram>(MapMetadata(OldSubprogramMDNode, VMap));
Alon Mishne07d949f2014-03-12 14:42:51 +0000191
Alon Mishnead312152014-03-18 09:41:07 +0000192 for (DICompileUnit CU : Finder.compile_units()) {
Alon Mishne07d949f2014-03-12 14:42:51 +0000193 DIArray Subprograms(CU.getSubprograms());
194
195 // If the compile unit's function list contains the old function, it should
196 // also contain the new one.
197 for (unsigned i = 0; i < Subprograms.getNumElements(); i++) {
198 if ((MDNode*)Subprograms.getElement(i) == OldSubprogramMDNode) {
Duncan P. N. Exon Smithb13f7d22014-12-06 00:48:13 +0000199 AddOperand(CU, Subprograms, NewSubprogram);
200 break;
Alon Mishne07d949f2014-03-12 14:42:51 +0000201 }
202 }
203 }
204}
205
Sanjay Patelabf70232015-03-10 18:41:22 +0000206/// Return a copy of the specified function, but without
Chris Lattnerfb311d22002-11-19 23:12:22 +0000207/// embedding the function into another module. Also, any references specified
Devang Patelb8f11de2010-06-23 23:55:51 +0000208/// in the VMap are changed to refer to their mapped value instead of the
209/// original one. If any of the arguments to the function are in the VMap,
210/// the arguments are deleted from the resultant function. The VMap is
Chris Lattnerfb311d22002-11-19 23:12:22 +0000211/// updated to include mappings from all of the instructions and basicblocks in
212/// the function from their old to new values.
213///
Chris Lattner43f8d162011-01-08 08:15:20 +0000214Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap,
Dan Gohmanca26f792010-08-26 15:41:53 +0000215 bool ModuleLevelChanges,
Chris Lattneredad1282006-01-13 18:39:17 +0000216 ClonedCodeInfo *CodeInfo) {
Jay Foadb804a2b2011-07-12 14:06:48 +0000217 std::vector<Type*> ArgTypes;
Chris Lattnerfb311d22002-11-19 23:12:22 +0000218
219 // The user might be deleting arguments to the function by specifying them in
Devang Patelb8f11de2010-06-23 23:55:51 +0000220 // the VMap. If so, we need to not add the arguments to the arg ty vector
Chris Lattnerfb311d22002-11-19 23:12:22 +0000221 //
Chris Lattneredad1282006-01-13 18:39:17 +0000222 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
223 I != E; ++I)
Devang Patelb8f11de2010-06-23 23:55:51 +0000224 if (VMap.count(I) == 0) // Haven't mapped the argument to anything yet?
Chris Lattnerfb311d22002-11-19 23:12:22 +0000225 ArgTypes.push_back(I->getType());
226
227 // Create a new function type...
Owen Anderson4056ca92009-07-29 22:17:13 +0000228 FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(),
Chris Lattnerfb311d22002-11-19 23:12:22 +0000229 ArgTypes, F->getFunctionType()->isVarArg());
230
231 // Create the new function...
Gabor Greife9ecc682008-04-06 20:25:17 +0000232 Function *NewF = Function::Create(FTy, F->getLinkage(), F->getName());
Misha Brukmanb1c93172005-04-21 23:48:37 +0000233
Chris Lattnerfb311d22002-11-19 23:12:22 +0000234 // Loop over the arguments, copying the names of the mapped arguments over...
Chris Lattner531f9e92005-03-15 04:54:21 +0000235 Function::arg_iterator DestI = NewF->arg_begin();
Chris Lattneredad1282006-01-13 18:39:17 +0000236 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
237 I != E; ++I)
Devang Patelb8f11de2010-06-23 23:55:51 +0000238 if (VMap.count(I) == 0) { // Is this argument preserved?
Chris Lattnerfb311d22002-11-19 23:12:22 +0000239 DestI->setName(I->getName()); // Copy the name over...
Devang Patelb8f11de2010-06-23 23:55:51 +0000240 VMap[I] = DestI++; // Add mapping to VMap
Chris Lattnerfb311d22002-11-19 23:12:22 +0000241 }
242
Alon Mishne07d949f2014-03-12 14:42:51 +0000243 if (ModuleLevelChanges)
244 CloneDebugInfoMetadata(NewF, F, VMap);
245
Chris Lattnerd84dbb32009-08-27 04:02:30 +0000246 SmallVector<ReturnInst*, 8> Returns; // Ignore returns cloned.
Dan Gohmanca26f792010-08-26 15:41:53 +0000247 CloneFunctionInto(NewF, F, VMap, ModuleLevelChanges, Returns, "", CodeInfo);
Misha Brukmanb1c93172005-04-21 23:48:37 +0000248 return NewF;
Chris Lattnerfb311d22002-11-19 23:12:22 +0000249}
Brian Gaeke960707c2003-11-11 22:41:34 +0000250
Chris Lattner3df13f42006-05-27 01:22:24 +0000251
252
253namespace {
Sanjay Patelabf70232015-03-10 18:41:22 +0000254 /// This is a private class used to implement CloneAndPruneFunctionInto.
Nick Lewycky02d5f772009-10-25 06:33:48 +0000255 struct PruningFunctionCloner {
Chris Lattner3df13f42006-05-27 01:22:24 +0000256 Function *NewFunc;
257 const Function *OldFunc;
Devang Pateld8dedee2010-06-24 00:00:42 +0000258 ValueToValueMapTy &VMap;
Dan Gohmanca26f792010-08-26 15:41:53 +0000259 bool ModuleLevelChanges;
Chris Lattner3df13f42006-05-27 01:22:24 +0000260 const char *NameSuffix;
261 ClonedCodeInfo *CodeInfo;
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000262 CloningDirector *Director;
Andrew Kaylorf22fe4a2015-02-23 20:01:56 +0000263 ValueMapTypeRemapper *TypeMapper;
264 ValueMaterializer *Materializer;
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000265
Chris Lattner3df13f42006-05-27 01:22:24 +0000266 public:
267 PruningFunctionCloner(Function *newFunc, const Function *oldFunc,
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000268 ValueToValueMapTy &valueMap, bool moduleLevelChanges,
269 const char *nameSuffix, ClonedCodeInfo *codeInfo,
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000270 CloningDirector *Director)
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000271 : NewFunc(newFunc), OldFunc(oldFunc), VMap(valueMap),
272 ModuleLevelChanges(moduleLevelChanges), NameSuffix(nameSuffix),
273 CodeInfo(codeInfo), Director(Director) {
Andrew Kaylorf22fe4a2015-02-23 20:01:56 +0000274 // These are optional components. The Director may return null.
275 if (Director) {
276 TypeMapper = Director->getTypeRemapper();
277 Materializer = Director->getValueMaterializer();
278 } else {
279 TypeMapper = nullptr;
280 Materializer = nullptr;
281 }
Chris Lattner3df13f42006-05-27 01:22:24 +0000282 }
283
Sanjay Patelabf70232015-03-10 18:41:22 +0000284 /// The specified block is found to be reachable, clone it and
Eric Christophera5ec9252014-05-19 16:04:10 +0000285 /// anything that it can reach.
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000286 void CloneBlock(const BasicBlock *BB,
287 BasicBlock::const_iterator StartingInst,
Eric Christophera5ec9252014-05-19 16:04:10 +0000288 std::vector<const BasicBlock*> &ToClone);
Chris Lattner3df13f42006-05-27 01:22:24 +0000289 };
290}
291
Sanjay Patelabf70232015-03-10 18:41:22 +0000292/// The specified block is found to be reachable, clone it and
Eric Christophera5ec9252014-05-19 16:04:10 +0000293/// anything that it can reach.
Chris Lattner4bd8cda2007-03-02 03:11:20 +0000294void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000295 BasicBlock::const_iterator StartingInst,
Eric Christophera5ec9252014-05-19 16:04:10 +0000296 std::vector<const BasicBlock*> &ToClone){
297 WeakVH &BBEntry = VMap[BB];
Gerolf Hoflehner1da7cbd2014-04-26 05:43:41 +0000298
Eric Christophera5ec9252014-05-19 16:04:10 +0000299 // Have we already cloned this block?
300 if (BBEntry) return;
301
Gerolf Hoflehner3282af12014-04-30 22:05:02 +0000302 // Nope, clone it now.
Eric Christophera5ec9252014-05-19 16:04:10 +0000303 BasicBlock *NewBB;
304 BBEntry = NewBB = BasicBlock::Create(BB->getContext());
305 if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
306
307 // It is only legal to clone a function if a block address within that
308 // function is never referenced outside of the function. Given that, we
309 // want to map block addresses from the old function to block addresses in
310 // the clone. (This is different from the generic ValueMapper
311 // implementation, which generates an invalid blockaddress when
312 // cloning a function.)
313 //
314 // Note that we don't need to fix the mapping for unreachable blocks;
315 // the default mapping there is safe.
316 if (BB->hasAddressTaken()) {
317 Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
318 const_cast<BasicBlock*>(BB));
319 VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
320 }
Eli Friedman688db1d2011-10-21 20:45:19 +0000321
Chris Lattner3df13f42006-05-27 01:22:24 +0000322 bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000323
Chris Lattner3df13f42006-05-27 01:22:24 +0000324 // Loop over all instructions, and copy them over, DCE'ing as we go. This
325 // loop doesn't include the terminator.
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000326 for (BasicBlock::const_iterator II = StartingInst, IE = --BB->end();
Chris Lattner3df13f42006-05-27 01:22:24 +0000327 II != IE; ++II) {
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000328 // If the "Director" remaps the instruction, don't clone it.
329 if (Director) {
330 CloningDirector::CloningAction Action
331 = Director->handleInstruction(VMap, II, NewBB);
332 // If the cloning director says stop, we want to stop everything, not
333 // just break out of the loop (which would cause the terminator to be
334 // cloned). The cloning director is responsible for inserting a proper
335 // terminator into the new basic block in this case.
336 if (Action == CloningDirector::StopCloningBB)
337 return;
338 // If the cloning director says skip, continue to the next instruction.
339 // In this case, the cloning director is responsible for mapping the
340 // skipped instruction to some value that is defined in the new
341 // basic block.
342 if (Action == CloningDirector::SkipInstruction)
343 continue;
344 }
345
Chandler Carruth21211992012-03-25 04:03:40 +0000346 Instruction *NewInst = II->clone();
347
348 // Eagerly remap operands to the newly cloned instruction, except for PHI
349 // nodes for which we defer processing until we update the CFG.
350 if (!isa<PHINode>(NewInst)) {
351 RemapInstruction(NewInst, VMap,
Andrew Kaylorf22fe4a2015-02-23 20:01:56 +0000352 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
353 TypeMapper, Materializer);
Chandler Carruth21211992012-03-25 04:03:40 +0000354
355 // If we can simplify this instruction to some other value, simply add
356 // a mapping to that value rather than inserting a new instruction into
357 // the basic block.
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000358 if (Value *V =
359 SimplifyInstruction(NewInst, BB->getModule()->getDataLayout())) {
Chandler Carruth21211992012-03-25 04:03:40 +0000360 // On the off-chance that this simplifies to an instruction in the old
361 // function, map it back into the new function.
362 if (Value *MappedV = VMap.lookup(V))
363 V = MappedV;
364
365 VMap[II] = V;
366 delete NewInst;
367 continue;
368 }
Chris Lattner3df13f42006-05-27 01:22:24 +0000369 }
Devang Patel4bed3562009-02-10 07:48:18 +0000370
Chris Lattner3df13f42006-05-27 01:22:24 +0000371 if (II->hasName())
372 NewInst->setName(II->getName()+NameSuffix);
Devang Patelb8f11de2010-06-23 23:55:51 +0000373 VMap[II] = NewInst; // Add instruction map to value.
Chandler Carruth21211992012-03-25 04:03:40 +0000374 NewBB->getInstList().push_back(NewInst);
Dale Johannesen900aaa32009-03-10 22:20:02 +0000375 hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
Chris Lattner3df13f42006-05-27 01:22:24 +0000376 if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
377 if (isa<ConstantInt>(AI->getArraySize()))
378 hasStaticAllocas = true;
379 else
380 hasDynamicAllocas = true;
381 }
382 }
383
Chris Lattnercc340c02006-06-01 19:19:23 +0000384 // Finally, clone over the terminator.
385 const TerminatorInst *OldTI = BB->getTerminator();
386 bool TerminatorDone = false;
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000387 if (Director) {
388 CloningDirector::CloningAction Action
389 = Director->handleInstruction(VMap, OldTI, NewBB);
390 // If the cloning director says stop, we want to stop everything, not
391 // just break out of the loop (which would cause the terminator to be
392 // cloned). The cloning director is responsible for inserting a proper
393 // terminator into the new basic block in this case.
394 if (Action == CloningDirector::StopCloningBB)
395 return;
Andrew Kaylor6b67d422015-03-11 23:22:06 +0000396 if (Action == CloningDirector::CloneSuccessors) {
397 // If the director says to skip with a terminate instruction, we still
398 // need to clone this block's successors.
399 const TerminatorInst *TI = BB->getTerminator();
400 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
401 ToClone.push_back(TI->getSuccessor(i));
402 return;
403 }
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000404 assert(Action != CloningDirector::SkipInstruction &&
405 "SkipInstruction is not valid for terminators.");
406 }
Chris Lattnercc340c02006-06-01 19:19:23 +0000407 if (const BranchInst *BI = dyn_cast<BranchInst>(OldTI)) {
408 if (BI->isConditional()) {
409 // If the condition was a known constant in the callee...
Zhou Sheng75b871f2007-01-11 12:24:14 +0000410 ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition());
411 // Or is a known constant in the caller...
Craig Topperf40110f2014-04-25 05:29:35 +0000412 if (!Cond) {
Rafael Espindolac2240ad2010-10-13 02:08:17 +0000413 Value *V = VMap[BI->getCondition()];
414 Cond = dyn_cast_or_null<ConstantInt>(V);
415 }
Zhou Sheng75b871f2007-01-11 12:24:14 +0000416
417 // Constant fold to uncond branch!
418 if (Cond) {
Reid Spencercddc9df2007-01-12 04:24:46 +0000419 BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue());
Devang Patelb8f11de2010-06-23 23:55:51 +0000420 VMap[OldTI] = BranchInst::Create(Dest, NewBB);
Chris Lattner4bd8cda2007-03-02 03:11:20 +0000421 ToClone.push_back(Dest);
Chris Lattnercc340c02006-06-01 19:19:23 +0000422 TerminatorDone = true;
423 }
424 }
425 } else if (const SwitchInst *SI = dyn_cast<SwitchInst>(OldTI)) {
426 // If switching on a value known constant in the caller.
427 ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition());
Craig Topperf40110f2014-04-25 05:29:35 +0000428 if (!Cond) { // Or known constant after constant prop in the callee...
Rafael Espindolac2240ad2010-10-13 02:08:17 +0000429 Value *V = VMap[SI->getCondition()];
430 Cond = dyn_cast_or_null<ConstantInt>(V);
431 }
Chris Lattnercc340c02006-06-01 19:19:23 +0000432 if (Cond) { // Constant fold to uncond branch!
Stepan Dyatkovskiy5b648af2012-03-08 07:06:20 +0000433 SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond);
434 BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
Devang Patelb8f11de2010-06-23 23:55:51 +0000435 VMap[OldTI] = BranchInst::Create(Dest, NewBB);
Chris Lattner4bd8cda2007-03-02 03:11:20 +0000436 ToClone.push_back(Dest);
Chris Lattnercc340c02006-06-01 19:19:23 +0000437 TerminatorDone = true;
438 }
439 }
440
441 if (!TerminatorDone) {
Nick Lewycky42fb7452009-09-27 07:38:41 +0000442 Instruction *NewInst = OldTI->clone();
Chris Lattnercc340c02006-06-01 19:19:23 +0000443 if (OldTI->hasName())
444 NewInst->setName(OldTI->getName()+NameSuffix);
445 NewBB->getInstList().push_back(NewInst);
Devang Patelb8f11de2010-06-23 23:55:51 +0000446 VMap[OldTI] = NewInst; // Add instruction map to value.
Chris Lattnercc340c02006-06-01 19:19:23 +0000447
448 // Recursively clone any reachable successor blocks.
449 const TerminatorInst *TI = BB->getTerminator();
450 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
Chris Lattner4bd8cda2007-03-02 03:11:20 +0000451 ToClone.push_back(TI->getSuccessor(i));
Chris Lattnercc340c02006-06-01 19:19:23 +0000452 }
453
Chris Lattner3df13f42006-05-27 01:22:24 +0000454 if (CodeInfo) {
455 CodeInfo->ContainsCalls |= hasCalls;
Chris Lattner3df13f42006-05-27 01:22:24 +0000456 CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
457 CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
458 BB != &BB->getParent()->front();
459 }
Chris Lattner3df13f42006-05-27 01:22:24 +0000460}
461
Sanjay Patelabf70232015-03-10 18:41:22 +0000462/// This works like CloneAndPruneFunctionInto, except that it does not clone the
463/// entire function. Instead it starts at an instruction provided by the caller
464/// and copies (and prunes) only the code reachable from that instruction.
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000465void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
466 const Instruction *StartingInst,
Devang Pateld8dedee2010-06-24 00:00:42 +0000467 ValueToValueMapTy &VMap,
Dan Gohmanca26f792010-08-26 15:41:53 +0000468 bool ModuleLevelChanges,
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000469 SmallVectorImpl<ReturnInst *> &Returns,
Chris Lattner3df13f42006-05-27 01:22:24 +0000470 const char *NameSuffix,
Chris Lattnerad84a732007-01-30 23:22:39 +0000471 ClonedCodeInfo *CodeInfo,
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000472 CloningDirector *Director) {
Chris Lattner3df13f42006-05-27 01:22:24 +0000473 assert(NameSuffix && "NameSuffix cannot be null!");
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000474
Andrew Kaylorf22fe4a2015-02-23 20:01:56 +0000475 ValueMapTypeRemapper *TypeMapper = nullptr;
476 ValueMaterializer *Materializer = nullptr;
477
478 if (Director) {
479 TypeMapper = Director->getTypeRemapper();
480 Materializer = Director->getValueMaterializer();
481 }
482
Chris Lattner3df13f42006-05-27 01:22:24 +0000483#ifndef NDEBUG
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000484 // If the cloning starts at the begining of the function, verify that
485 // the function arguments are mapped.
486 if (!StartingInst)
487 for (Function::const_arg_iterator II = OldFunc->arg_begin(),
488 E = OldFunc->arg_end(); II != E; ++II)
489 assert(VMap.count(II) && "No mapping from source argument specified!");
Chris Lattner3df13f42006-05-27 01:22:24 +0000490#endif
Duncan Sandsdd7daee2008-05-26 19:58:59 +0000491
Dan Gohmanca26f792010-08-26 15:41:53 +0000492 PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000493 NameSuffix, CodeInfo, Director);
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000494 const BasicBlock *StartingBB;
495 if (StartingInst)
496 StartingBB = StartingInst->getParent();
497 else {
498 StartingBB = &OldFunc->getEntryBlock();
499 StartingInst = StartingBB->begin();
500 }
Chris Lattner3df13f42006-05-27 01:22:24 +0000501
Eric Christophera5ec9252014-05-19 16:04:10 +0000502 // Clone the entry block, and anything recursively reachable from it.
Chris Lattner4bd8cda2007-03-02 03:11:20 +0000503 std::vector<const BasicBlock*> CloneWorklist;
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000504 PFC.CloneBlock(StartingBB, StartingInst, CloneWorklist);
Chris Lattner4bd8cda2007-03-02 03:11:20 +0000505 while (!CloneWorklist.empty()) {
506 const BasicBlock *BB = CloneWorklist.back();
507 CloneWorklist.pop_back();
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000508 PFC.CloneBlock(BB, BB->begin(), CloneWorklist);
Chris Lattner4bd8cda2007-03-02 03:11:20 +0000509 }
Eric Christophera5ec9252014-05-19 16:04:10 +0000510
Chris Lattner3df13f42006-05-27 01:22:24 +0000511 // Loop over all of the basic blocks in the old function. If the block was
512 // reachable, we have cloned it and the old block is now in the value map:
513 // insert it into the new function in the right order. If not, ignore it.
514 //
Chris Lattnercc340c02006-06-01 19:19:23 +0000515 // Defer PHI resolution until rest of function is resolved.
Chris Lattnerd84dbb32009-08-27 04:02:30 +0000516 SmallVector<const PHINode*, 16> PHIToResolve;
Chris Lattner3df13f42006-05-27 01:22:24 +0000517 for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
518 BI != BE; ++BI) {
Rafael Espindolac2240ad2010-10-13 02:08:17 +0000519 Value *V = VMap[BI];
520 BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
Eric Christophera5ec9252014-05-19 16:04:10 +0000521 if (!NewBB) continue; // Dead block.
Chris Lattnercc340c02006-06-01 19:19:23 +0000522
Chris Lattner3df13f42006-05-27 01:22:24 +0000523 // Add the new block to the new function.
524 NewFunc->getBasicBlockList().push_back(NewBB);
Devang Patelf6eeaeb2009-11-10 23:06:00 +0000525
Chris Lattner3df13f42006-05-27 01:22:24 +0000526 // Handle PHI nodes specially, as we have to remove references to dead
527 // blocks.
Andrew Kaylor3170e562015-03-20 21:42:54 +0000528 for (BasicBlock::const_iterator I = BI->begin(), E = BI->end(); I != E; ++I) {
529 // PHI nodes may have been remapped to non-PHI nodes by the caller or
530 // during the cloning process.
531 if (const PHINode *PN = dyn_cast<PHINode>(I)) {
532 if (isa<PHINode>(VMap[PN]))
533 PHIToResolve.push_back(PN);
534 else
535 break;
536 } else {
Chandler Carruth21211992012-03-25 04:03:40 +0000537 break;
Andrew Kaylor3170e562015-03-20 21:42:54 +0000538 }
539 }
Chandler Carruth21211992012-03-25 04:03:40 +0000540
541 // Finally, remap the terminator instructions, as those can't be remapped
542 // until all BBs are mapped.
543 RemapInstruction(NewBB->getTerminator(), VMap,
Andrew Kaylorf22fe4a2015-02-23 20:01:56 +0000544 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
545 TypeMapper, Materializer);
Chris Lattner3df13f42006-05-27 01:22:24 +0000546 }
Chris Lattnercc340c02006-06-01 19:19:23 +0000547
548 // Defer PHI resolution until rest of function is resolved, PHI resolution
549 // requires the CFG to be up-to-date.
550 for (unsigned phino = 0, e = PHIToResolve.size(); phino != e; ) {
551 const PHINode *OPN = PHIToResolve[phino];
Chris Lattnercc340c02006-06-01 19:19:23 +0000552 unsigned NumPreds = OPN->getNumIncomingValues();
Chris Lattnercc340c02006-06-01 19:19:23 +0000553 const BasicBlock *OldBB = OPN->getParent();
Devang Patelb8f11de2010-06-23 23:55:51 +0000554 BasicBlock *NewBB = cast<BasicBlock>(VMap[OldBB]);
Chris Lattnercc340c02006-06-01 19:19:23 +0000555
556 // Map operands for blocks that are live and remove operands for blocks
557 // that are dead.
558 for (; phino != PHIToResolve.size() &&
559 PHIToResolve[phino]->getParent() == OldBB; ++phino) {
560 OPN = PHIToResolve[phino];
Devang Patelb8f11de2010-06-23 23:55:51 +0000561 PHINode *PN = cast<PHINode>(VMap[OPN]);
Chris Lattnercc340c02006-06-01 19:19:23 +0000562 for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
Rafael Espindolac2240ad2010-10-13 02:08:17 +0000563 Value *V = VMap[PN->getIncomingBlock(pred)];
Chris Lattner43f8d162011-01-08 08:15:20 +0000564 if (BasicBlock *MappedBlock = cast_or_null<BasicBlock>(V)) {
Owen Andersone70b6372009-07-05 22:41:43 +0000565 Value *InVal = MapValue(PN->getIncomingValue(pred),
Chris Lattner43f8d162011-01-08 08:15:20 +0000566 VMap,
567 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
Chris Lattnercc340c02006-06-01 19:19:23 +0000568 assert(InVal && "Unknown input value?");
569 PN->setIncomingValue(pred, InVal);
570 PN->setIncomingBlock(pred, MappedBlock);
571 } else {
572 PN->removeIncomingValue(pred, false);
573 --pred, --e; // Revisit the next entry.
574 }
575 }
576 }
577
578 // The loop above has removed PHI entries for those blocks that are dead
579 // and has updated others. However, if a block is live (i.e. copied over)
580 // but its terminator has been changed to not go to this block, then our
581 // phi nodes will have invalid entries. Update the PHI nodes in this
582 // case.
583 PHINode *PN = cast<PHINode>(NewBB->begin());
584 NumPreds = std::distance(pred_begin(NewBB), pred_end(NewBB));
585 if (NumPreds != PN->getNumIncomingValues()) {
586 assert(NumPreds < PN->getNumIncomingValues());
587 // Count how many times each predecessor comes to this block.
588 std::map<BasicBlock*, unsigned> PredCount;
Duncan P. N. Exon Smith6c990152014-07-21 17:06:51 +0000589 for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB);
590 PI != E; ++PI)
591 --PredCount[*PI];
Chris Lattnercc340c02006-06-01 19:19:23 +0000592
593 // Figure out how many entries to remove from each PHI.
594 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
595 ++PredCount[PN->getIncomingBlock(i)];
596
597 // At this point, the excess predecessor entries are positive in the
598 // map. Loop over all of the PHIs and remove excess predecessor
599 // entries.
600 BasicBlock::iterator I = NewBB->begin();
601 for (; (PN = dyn_cast<PHINode>(I)); ++I) {
602 for (std::map<BasicBlock*, unsigned>::iterator PCI =PredCount.begin(),
603 E = PredCount.end(); PCI != E; ++PCI) {
604 BasicBlock *Pred = PCI->first;
605 for (unsigned NumToRemove = PCI->second; NumToRemove; --NumToRemove)
606 PN->removeIncomingValue(Pred, false);
607 }
608 }
609 }
610
611 // If the loops above have made these phi nodes have 0 or 1 operand,
612 // replace them with undef or the input value. We must do this for
613 // correctness, because 0-operand phis are not valid.
614 PN = cast<PHINode>(NewBB->begin());
615 if (PN->getNumIncomingValues() == 0) {
616 BasicBlock::iterator I = NewBB->begin();
617 BasicBlock::const_iterator OldI = OldBB->begin();
618 while ((PN = dyn_cast<PHINode>(I++))) {
Owen Andersonb292b8c2009-07-30 23:03:37 +0000619 Value *NV = UndefValue::get(PN->getType());
Chris Lattnercc340c02006-06-01 19:19:23 +0000620 PN->replaceAllUsesWith(NV);
Devang Patelb8f11de2010-06-23 23:55:51 +0000621 assert(VMap[OldI] == PN && "VMap mismatch");
622 VMap[OldI] = NV;
Chris Lattnercc340c02006-06-01 19:19:23 +0000623 PN->eraseFromParent();
624 ++OldI;
625 }
Chris Lattnercc340c02006-06-01 19:19:23 +0000626 }
627 }
Chandler Carruthef82cf52012-03-25 10:34:54 +0000628
629 // Make a second pass over the PHINodes now that all of them have been
630 // remapped into the new function, simplifying the PHINode and performing any
631 // recursive simplifications exposed. This will transparently update the
Chandler Carruth772c88b2012-03-28 08:38:27 +0000632 // WeakVH in the VMap. Notably, we rely on that so that if we coalesce
Chandler Carruthef82cf52012-03-25 10:34:54 +0000633 // two PHINodes, the iteration over the old PHIs remains valid, and the
634 // mapping will just map us to the new node (which may not even be a PHI
635 // node).
636 for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx)
637 if (PHINode *PN = dyn_cast<PHINode>(VMap[PHIToResolve[Idx]]))
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000638 recursivelySimplifyInstruction(PN);
Chandler Carruthef82cf52012-03-25 10:34:54 +0000639
Chris Lattner237ccf22006-09-13 21:27:00 +0000640 // Now that the inlined function body has been fully constructed, go through
Sanjay Patel51bd9422015-03-10 18:37:05 +0000641 // and zap unconditional fall-through branches. This happens all the time when
Chris Lattner237ccf22006-09-13 21:27:00 +0000642 // specializing code: code specialization turns conditional branches into
643 // uncond branches, and this code folds them.
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000644 Function::iterator Begin = cast<BasicBlock>(VMap[StartingBB]);
Chandler Carruth772c88b2012-03-28 08:38:27 +0000645 Function::iterator I = Begin;
Chris Lattner237ccf22006-09-13 21:27:00 +0000646 while (I != NewFunc->end()) {
Chandler Carruth772c88b2012-03-28 08:38:27 +0000647 // Check if this block has become dead during inlining or other
648 // simplifications. Note that the first block will appear dead, as it has
649 // not yet been wired up properly.
650 if (I != Begin && (pred_begin(I) == pred_end(I) ||
651 I->getSinglePredecessor() == I)) {
652 BasicBlock *DeadBB = I++;
653 DeleteDeadBlock(DeadBB);
654 continue;
655 }
656
657 // We need to simplify conditional branches and switches with a constant
658 // operand. We try to prune these out when cloning, but if the
659 // simplification required looking through PHI nodes, those are only
660 // available after forming the full basic block. That may leave some here,
661 // and we still want to prune the dead code as early as possible.
662 ConstantFoldTerminator(I);
663
Chris Lattner237ccf22006-09-13 21:27:00 +0000664 BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
665 if (!BI || BI->isConditional()) { ++I; continue; }
666
667 BasicBlock *Dest = BI->getSuccessor(0);
Chandler Carruthef82cf52012-03-25 10:34:54 +0000668 if (!Dest->getSinglePredecessor()) {
Chris Lattnerce494222007-02-01 18:48:38 +0000669 ++I; continue;
670 }
Chandler Carruthef82cf52012-03-25 10:34:54 +0000671
672 // We shouldn't be able to get single-entry PHI nodes here, as instsimplify
673 // above should have zapped all of them..
674 assert(!isa<PHINode>(Dest->begin()));
675
Chris Lattner237ccf22006-09-13 21:27:00 +0000676 // We know all single-entry PHI nodes in the inlined function have been
677 // removed, so we just need to splice the blocks.
678 BI->eraseFromParent();
679
Eric Christopher96513122011-06-23 06:24:52 +0000680 // Make all PHI nodes that referred to Dest now refer to I as their source.
681 Dest->replaceAllUsesWith(I);
682
Jay Foad61ea0e42011-06-23 09:09:15 +0000683 // Move all the instructions in the succ to the pred.
684 I->getInstList().splice(I->end(), Dest->getInstList());
685
Chris Lattner237ccf22006-09-13 21:27:00 +0000686 // Remove the dest block.
687 Dest->eraseFromParent();
688
689 // Do not increment I, iteratively merge all things this block branches to.
690 }
Chandler Carruth49da9332012-04-06 17:21:31 +0000691
Sanjay Patel51bd9422015-03-10 18:37:05 +0000692 // Make a final pass over the basic blocks from the old function to gather
Chandler Carruth49da9332012-04-06 17:21:31 +0000693 // any return instructions which survived folding. We have to do this here
694 // because we can iteratively remove and merge returns above.
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000695 for (Function::iterator I = cast<BasicBlock>(VMap[StartingBB]),
Chandler Carruth49da9332012-04-06 17:21:31 +0000696 E = NewFunc->end();
697 I != E; ++I)
698 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator()))
699 Returns.push_back(RI);
Chris Lattner3df13f42006-05-27 01:22:24 +0000700}
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000701
702
Sanjay Patelabf70232015-03-10 18:41:22 +0000703/// This works exactly like CloneFunctionInto,
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000704/// except that it does some simple constant prop and DCE on the fly. The
705/// effect of this is to copy significantly less code in cases where (for
706/// example) a function call with constant arguments is inlined, and those
707/// constant arguments cause a significant amount of code in the callee to be
708/// dead. Since this doesn't produce an exact copy of the input, it can't be
709/// used for things like CloneFunction or CloneModule.
710void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
711 ValueToValueMapTy &VMap,
712 bool ModuleLevelChanges,
713 SmallVectorImpl<ReturnInst*> &Returns,
714 const char *NameSuffix,
715 ClonedCodeInfo *CodeInfo,
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000716 Instruction *TheCall) {
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000717 CloneAndPruneIntoFromInst(NewFunc, OldFunc, OldFunc->front().begin(), VMap,
718 ModuleLevelChanges, Returns, NameSuffix, CodeInfo,
719 nullptr);
Andrew Kaylor527c5dc2015-02-18 18:31:51 +0000720}