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Chris Lattner6c2e2e52002-11-19 22:04:49 +00001//===- CloneFunction.cpp - Clone a function into another function ---------===//
Misha Brukmanfd939082005-04-21 23:48:37 +00002//
John Criswellb576c942003-10-20 19:43:21 +00003// The LLVM Compiler Infrastructure
4//
Chris Lattner4ee451d2007-12-29 20:36:04 +00005// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
Misha Brukmanfd939082005-04-21 23:48:37 +00007//
John Criswellb576c942003-10-20 19:43:21 +00008//===----------------------------------------------------------------------===//
Chris Lattner6c2e2e52002-11-19 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 Lattnerfa703a42002-03-29 19:03:54 +000015
Chris Lattner309f1932002-11-19 20:59:41 +000016#include "llvm/Transforms/Utils/Cloning.h"
Chandler Carruthd04a8d42012-12-03 16:50:05 +000017#include "llvm/ADT/SmallVector.h"
18#include "llvm/Analysis/ConstantFolding.h"
19#include "llvm/Analysis/InstructionSimplify.h"
Bill Wendling0bcbd1d2012-06-28 00:05:13 +000020#include "llvm/DebugInfo.h"
Chandler Carruth0b8c9a82013-01-02 11:36:10 +000021#include "llvm/IR/Constants.h"
22#include "llvm/IR/DerivedTypes.h"
23#include "llvm/IR/Function.h"
24#include "llvm/IR/GlobalVariable.h"
25#include "llvm/IR/Instructions.h"
26#include "llvm/IR/IntrinsicInst.h"
27#include "llvm/IR/LLVMContext.h"
28#include "llvm/IR/Metadata.h"
Chris Lattner35033ef2006-06-01 19:19:23 +000029#include "llvm/Support/CFG.h"
Chandler Carruthafff3302012-03-28 08:38:27 +000030#include "llvm/Transforms/Utils/BasicBlockUtils.h"
31#include "llvm/Transforms/Utils/Local.h"
Dan Gohman05ea54e2010-08-24 18:50:07 +000032#include "llvm/Transforms/Utils/ValueMapper.h"
Chris Lattner5e665f52007-02-03 00:08:31 +000033#include <map>
Chris Lattnerf7703df2004-01-09 06:12:26 +000034using namespace llvm;
Brian Gaeked0fde302003-11-11 22:41:34 +000035
Chris Lattner17d145d2003-04-18 03:50:09 +000036// CloneBasicBlock - See comments in Cloning.h
Chris Lattnerf7703df2004-01-09 06:12:26 +000037BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
Devang Patel774cca72010-06-24 00:00:42 +000038 ValueToValueMapTy &VMap,
Benjamin Kramer5deb57c2010-01-27 19:58:47 +000039 const Twine &NameSuffix, Function *F,
Chris Lattnera4c29d22006-01-13 18:39:17 +000040 ClonedCodeInfo *CodeInfo) {
Owen Anderson1d0be152009-08-13 21:58:54 +000041 BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
Chris Lattner17d145d2003-04-18 03:50:09 +000042 if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
43
Chris Lattnera4c29d22006-01-13 18:39:17 +000044 bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
45
46 // Loop over all instructions, and copy them over.
Chris Lattner17d145d2003-04-18 03:50:09 +000047 for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
48 II != IE; ++II) {
Nick Lewycky67760642009-09-27 07:38:41 +000049 Instruction *NewInst = II->clone();
Chris Lattner17d145d2003-04-18 03:50:09 +000050 if (II->hasName())
51 NewInst->setName(II->getName()+NameSuffix);
52 NewBB->getInstList().push_back(NewInst);
Devang Patel29d3dd82010-06-23 23:55:51 +000053 VMap[II] = NewInst; // Add instruction map to value.
Chris Lattnera4c29d22006-01-13 18:39:17 +000054
Dale Johannesen8aa90fe2009-03-10 22:20:02 +000055 hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
Chris Lattnera4c29d22006-01-13 18:39:17 +000056 if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
57 if (isa<ConstantInt>(AI->getArraySize()))
58 hasStaticAllocas = true;
59 else
60 hasDynamicAllocas = true;
61 }
62 }
63
64 if (CodeInfo) {
65 CodeInfo->ContainsCalls |= hasCalls;
Chris Lattnera4c29d22006-01-13 18:39:17 +000066 CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
67 CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
Dan Gohmanecb7a772007-03-22 16:38:57 +000068 BB != &BB->getParent()->getEntryBlock();
Chris Lattner17d145d2003-04-18 03:50:09 +000069 }
70 return NewBB;
71}
72
Chris Lattnerfa703a42002-03-29 19:03:54 +000073// Clone OldFunc into NewFunc, transforming the old arguments into references to
Dan Gohman6cb8c232010-08-26 15:41:53 +000074// VMap values.
Chris Lattnerfa703a42002-03-29 19:03:54 +000075//
Chris Lattnerf7703df2004-01-09 06:12:26 +000076void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
Devang Patel774cca72010-06-24 00:00:42 +000077 ValueToValueMapTy &VMap,
Dan Gohman6cb8c232010-08-26 15:41:53 +000078 bool ModuleLevelChanges,
Chris Lattnerec1bea02009-08-27 04:02:30 +000079 SmallVectorImpl<ReturnInst*> &Returns,
Mon P Wangd24397a2011-12-23 02:18:32 +000080 const char *NameSuffix, ClonedCodeInfo *CodeInfo,
James Molloya84a83b2013-05-28 15:17:05 +000081 ValueMapTypeRemapper *TypeMapper,
82 ValueMaterializer *Materializer) {
Chris Lattnerdcd80402002-11-19 21:54:07 +000083 assert(NameSuffix && "NameSuffix cannot be null!");
Misha Brukmanfd939082005-04-21 23:48:37 +000084
Chris Lattnerd1801552002-11-19 22:54:01 +000085#ifndef NDEBUG
Chris Lattnera4c29d22006-01-13 18:39:17 +000086 for (Function::const_arg_iterator I = OldFunc->arg_begin(),
87 E = OldFunc->arg_end(); I != E; ++I)
Devang Patel29d3dd82010-06-23 23:55:51 +000088 assert(VMap.count(I) && "No mapping from source argument specified!");
Chris Lattnerd1801552002-11-19 22:54:01 +000089#endif
Chris Lattnerfa703a42002-03-29 19:03:54 +000090
Joey Gouly0f57a982013-04-10 10:37:38 +000091 AttributeSet OldAttrs = OldFunc->getAttributes();
92 // Clone any argument attributes that are present in the VMap.
93 for (Function::const_arg_iterator I = OldFunc->arg_begin(),
94 E = OldFunc->arg_end();
95 I != E; ++I)
96 if (Argument *Anew = dyn_cast<Argument>(VMap[I])) {
97 AttributeSet attrs =
98 OldAttrs.getParamAttributes(I->getArgNo() + 1);
99 if (attrs.getNumSlots() > 0)
100 Anew->addAttr(attrs);
101 }
Andrew Lenharth82cf32e2008-10-07 18:08:38 +0000102
Joey Gouly0f57a982013-04-10 10:37:38 +0000103 NewFunc->setAttributes(NewFunc->getAttributes()
104 .addAttributes(NewFunc->getContext(),
105 AttributeSet::ReturnIndex,
106 OldAttrs.getRetAttributes()));
107 NewFunc->setAttributes(NewFunc->getAttributes()
108 .addAttributes(NewFunc->getContext(),
109 AttributeSet::FunctionIndex,
110 OldAttrs.getFnAttributes()));
Anton Korobeynikov9e49f1b2008-03-23 16:03:00 +0000111
Chris Lattnerfa703a42002-03-29 19:03:54 +0000112 // Loop over all of the basic blocks in the function, cloning them as
Chris Lattnerdcd80402002-11-19 21:54:07 +0000113 // appropriate. Note that we save BE this way in order to handle cloning of
114 // recursive functions into themselves.
Chris Lattnerfa703a42002-03-29 19:03:54 +0000115 //
116 for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
117 BI != BE; ++BI) {
Chris Lattner18961502002-06-25 16:12:52 +0000118 const BasicBlock &BB = *BI;
Misha Brukmanfd939082005-04-21 23:48:37 +0000119
Chris Lattner17d145d2003-04-18 03:50:09 +0000120 // Create a new basic block and copy instructions into it!
Chris Lattnerb5fa5fc2011-01-08 08:15:20 +0000121 BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo);
Chris Lattnerfa703a42002-03-29 19:03:54 +0000122
Eli Friedman4090e1c2011-10-21 20:45:19 +0000123 // Add basic block mapping.
124 VMap[&BB] = CBB;
125
126 // It is only legal to clone a function if a block address within that
127 // function is never referenced outside of the function. Given that, we
128 // want to map block addresses from the old function to block addresses in
129 // the clone. (This is different from the generic ValueMapper
130 // implementation, which generates an invalid blockaddress when
131 // cloning a function.)
132 if (BB.hasAddressTaken()) {
133 Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
134 const_cast<BasicBlock*>(&BB));
135 VMap[OldBBAddr] = BlockAddress::get(NewFunc, CBB);
136 }
137
138 // Note return instructions for the caller.
Chris Lattnerdcd80402002-11-19 21:54:07 +0000139 if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
140 Returns.push_back(RI);
Chris Lattnerfa703a42002-03-29 19:03:54 +0000141 }
142
Misha Brukmanfd939082005-04-21 23:48:37 +0000143 // Loop over all of the instructions in the function, fixing up operand
Devang Patel29d3dd82010-06-23 23:55:51 +0000144 // references as we go. This uses VMap to do all the hard work.
Devang Patel29d3dd82010-06-23 23:55:51 +0000145 for (Function::iterator BB = cast<BasicBlock>(VMap[OldFunc->begin()]),
Nick Lewycky280a6e62008-04-25 16:53:59 +0000146 BE = NewFunc->end(); BB != BE; ++BB)
Chris Lattnerfa703a42002-03-29 19:03:54 +0000147 // Loop over all instructions, fixing each one as we find it...
Chris Lattnera33ceaa2004-02-04 21:44:26 +0000148 for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II)
Chris Lattnerb5fa5fc2011-01-08 08:15:20 +0000149 RemapInstruction(II, VMap,
Mon P Wangd24397a2011-12-23 02:18:32 +0000150 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
James Molloya84a83b2013-05-28 15:17:05 +0000151 TypeMapper, Materializer);
Chris Lattnerfa703a42002-03-29 19:03:54 +0000152}
Chris Lattner5a8932f2002-11-19 23:12:22 +0000153
154/// CloneFunction - Return a copy of the specified function, but without
155/// embedding the function into another module. Also, any references specified
Devang Patel29d3dd82010-06-23 23:55:51 +0000156/// in the VMap are changed to refer to their mapped value instead of the
157/// original one. If any of the arguments to the function are in the VMap,
158/// the arguments are deleted from the resultant function. The VMap is
Chris Lattner5a8932f2002-11-19 23:12:22 +0000159/// updated to include mappings from all of the instructions and basicblocks in
160/// the function from their old to new values.
161///
Chris Lattnerb5fa5fc2011-01-08 08:15:20 +0000162Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap,
Dan Gohman6cb8c232010-08-26 15:41:53 +0000163 bool ModuleLevelChanges,
Chris Lattnera4c29d22006-01-13 18:39:17 +0000164 ClonedCodeInfo *CodeInfo) {
Jay Foad5fdd6c82011-07-12 14:06:48 +0000165 std::vector<Type*> ArgTypes;
Chris Lattner5a8932f2002-11-19 23:12:22 +0000166
167 // The user might be deleting arguments to the function by specifying them in
Devang Patel29d3dd82010-06-23 23:55:51 +0000168 // the VMap. If so, we need to not add the arguments to the arg ty vector
Chris Lattner5a8932f2002-11-19 23:12:22 +0000169 //
Chris Lattnera4c29d22006-01-13 18:39:17 +0000170 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
171 I != E; ++I)
Devang Patel29d3dd82010-06-23 23:55:51 +0000172 if (VMap.count(I) == 0) // Haven't mapped the argument to anything yet?
Chris Lattner5a8932f2002-11-19 23:12:22 +0000173 ArgTypes.push_back(I->getType());
174
175 // Create a new function type...
Owen Andersondebcb012009-07-29 22:17:13 +0000176 FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(),
Chris Lattner5a8932f2002-11-19 23:12:22 +0000177 ArgTypes, F->getFunctionType()->isVarArg());
178
179 // Create the new function...
Gabor Greif051a9502008-04-06 20:25:17 +0000180 Function *NewF = Function::Create(FTy, F->getLinkage(), F->getName());
Misha Brukmanfd939082005-04-21 23:48:37 +0000181
Chris Lattner5a8932f2002-11-19 23:12:22 +0000182 // Loop over the arguments, copying the names of the mapped arguments over...
Chris Lattnere4d5c442005-03-15 04:54:21 +0000183 Function::arg_iterator DestI = NewF->arg_begin();
Chris Lattnera4c29d22006-01-13 18:39:17 +0000184 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
185 I != E; ++I)
Devang Patel29d3dd82010-06-23 23:55:51 +0000186 if (VMap.count(I) == 0) { // Is this argument preserved?
Chris Lattner5a8932f2002-11-19 23:12:22 +0000187 DestI->setName(I->getName()); // Copy the name over...
Devang Patel29d3dd82010-06-23 23:55:51 +0000188 VMap[I] = DestI++; // Add mapping to VMap
Chris Lattner5a8932f2002-11-19 23:12:22 +0000189 }
190
Chris Lattnerec1bea02009-08-27 04:02:30 +0000191 SmallVector<ReturnInst*, 8> Returns; // Ignore returns cloned.
Dan Gohman6cb8c232010-08-26 15:41:53 +0000192 CloneFunctionInto(NewF, F, VMap, ModuleLevelChanges, Returns, "", CodeInfo);
Misha Brukmanfd939082005-04-21 23:48:37 +0000193 return NewF;
Chris Lattner5a8932f2002-11-19 23:12:22 +0000194}
Brian Gaeked0fde302003-11-11 22:41:34 +0000195
Chris Lattner83f03bf2006-05-27 01:22:24 +0000196
197
198namespace {
199 /// PruningFunctionCloner - This class is a private class used to implement
200 /// the CloneAndPruneFunctionInto method.
Nick Lewycky6726b6d2009-10-25 06:33:48 +0000201 struct PruningFunctionCloner {
Chris Lattner83f03bf2006-05-27 01:22:24 +0000202 Function *NewFunc;
203 const Function *OldFunc;
Devang Patel774cca72010-06-24 00:00:42 +0000204 ValueToValueMapTy &VMap;
Dan Gohman6cb8c232010-08-26 15:41:53 +0000205 bool ModuleLevelChanges;
Chris Lattner83f03bf2006-05-27 01:22:24 +0000206 const char *NameSuffix;
207 ClonedCodeInfo *CodeInfo;
Micah Villmow3574eca2012-10-08 16:38:25 +0000208 const DataLayout *TD;
Chris Lattner83f03bf2006-05-27 01:22:24 +0000209 public:
210 PruningFunctionCloner(Function *newFunc, const Function *oldFunc,
Devang Patel774cca72010-06-24 00:00:42 +0000211 ValueToValueMapTy &valueMap,
Dan Gohman6cb8c232010-08-26 15:41:53 +0000212 bool moduleLevelChanges,
Chris Lattner83f03bf2006-05-27 01:22:24 +0000213 const char *nameSuffix,
Chris Lattner1dfdf822007-01-30 23:22:39 +0000214 ClonedCodeInfo *codeInfo,
Micah Villmow3574eca2012-10-08 16:38:25 +0000215 const DataLayout *td)
Dan Gohman6cb8c232010-08-26 15:41:53 +0000216 : NewFunc(newFunc), OldFunc(oldFunc),
217 VMap(valueMap), ModuleLevelChanges(moduleLevelChanges),
Chandler Carruth6bbab862012-04-06 01:11:52 +0000218 NameSuffix(nameSuffix), CodeInfo(codeInfo), TD(td) {
Chris Lattner83f03bf2006-05-27 01:22:24 +0000219 }
220
221 /// CloneBlock - The specified block is found to be reachable, clone it and
222 /// anything that it can reach.
Chris Lattner67ef2412007-03-02 03:11:20 +0000223 void CloneBlock(const BasicBlock *BB,
224 std::vector<const BasicBlock*> &ToClone);
Chris Lattner83f03bf2006-05-27 01:22:24 +0000225 };
226}
227
228/// CloneBlock - The specified block is found to be reachable, clone it and
229/// anything that it can reach.
Chris Lattner67ef2412007-03-02 03:11:20 +0000230void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
231 std::vector<const BasicBlock*> &ToClone){
Chandler Carruthafff3302012-03-28 08:38:27 +0000232 WeakVH &BBEntry = VMap[BB];
Chris Lattner83f03bf2006-05-27 01:22:24 +0000233
234 // Have we already cloned this block?
235 if (BBEntry) return;
236
237 // Nope, clone it now.
238 BasicBlock *NewBB;
Owen Anderson1d0be152009-08-13 21:58:54 +0000239 BBEntry = NewBB = BasicBlock::Create(BB->getContext());
Chris Lattner83f03bf2006-05-27 01:22:24 +0000240 if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
241
Eli Friedman4090e1c2011-10-21 20:45:19 +0000242 // It is only legal to clone a function if a block address within that
243 // function is never referenced outside of the function. Given that, we
244 // want to map block addresses from the old function to block addresses in
245 // the clone. (This is different from the generic ValueMapper
246 // implementation, which generates an invalid blockaddress when
247 // cloning a function.)
248 //
249 // Note that we don't need to fix the mapping for unreachable blocks;
250 // the default mapping there is safe.
251 if (BB->hasAddressTaken()) {
252 Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
253 const_cast<BasicBlock*>(BB));
254 VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
255 }
256
257
Chris Lattner83f03bf2006-05-27 01:22:24 +0000258 bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
259
260 // Loop over all instructions, and copy them over, DCE'ing as we go. This
261 // loop doesn't include the terminator.
Chris Lattner35033ef2006-06-01 19:19:23 +0000262 for (BasicBlock::const_iterator II = BB->begin(), IE = --BB->end();
Chris Lattner83f03bf2006-05-27 01:22:24 +0000263 II != IE; ++II) {
Chandler Carruthd54f9a42012-03-25 04:03:40 +0000264 Instruction *NewInst = II->clone();
265
266 // Eagerly remap operands to the newly cloned instruction, except for PHI
267 // nodes for which we defer processing until we update the CFG.
268 if (!isa<PHINode>(NewInst)) {
269 RemapInstruction(NewInst, VMap,
270 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
271
272 // If we can simplify this instruction to some other value, simply add
273 // a mapping to that value rather than inserting a new instruction into
274 // the basic block.
275 if (Value *V = SimplifyInstruction(NewInst, TD)) {
276 // On the off-chance that this simplifies to an instruction in the old
277 // function, map it back into the new function.
278 if (Value *MappedV = VMap.lookup(V))
279 V = MappedV;
280
281 VMap[II] = V;
282 delete NewInst;
283 continue;
284 }
Chris Lattner83f03bf2006-05-27 01:22:24 +0000285 }
Devang Patelf66d7b52009-02-10 07:48:18 +0000286
Chris Lattner83f03bf2006-05-27 01:22:24 +0000287 if (II->hasName())
288 NewInst->setName(II->getName()+NameSuffix);
Devang Patel29d3dd82010-06-23 23:55:51 +0000289 VMap[II] = NewInst; // Add instruction map to value.
Chandler Carruthd54f9a42012-03-25 04:03:40 +0000290 NewBB->getInstList().push_back(NewInst);
Dale Johannesen8aa90fe2009-03-10 22:20:02 +0000291 hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
Chris Lattner83f03bf2006-05-27 01:22:24 +0000292 if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
293 if (isa<ConstantInt>(AI->getArraySize()))
294 hasStaticAllocas = true;
295 else
296 hasDynamicAllocas = true;
297 }
298 }
299
Chris Lattner35033ef2006-06-01 19:19:23 +0000300 // Finally, clone over the terminator.
301 const TerminatorInst *OldTI = BB->getTerminator();
302 bool TerminatorDone = false;
303 if (const BranchInst *BI = dyn_cast<BranchInst>(OldTI)) {
304 if (BI->isConditional()) {
305 // If the condition was a known constant in the callee...
Zhou Sheng6b6b6ef2007-01-11 12:24:14 +0000306 ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition());
307 // Or is a known constant in the caller...
Rafael Espindola6688c4a2010-10-13 02:08:17 +0000308 if (Cond == 0) {
309 Value *V = VMap[BI->getCondition()];
310 Cond = dyn_cast_or_null<ConstantInt>(V);
311 }
Zhou Sheng6b6b6ef2007-01-11 12:24:14 +0000312
313 // Constant fold to uncond branch!
314 if (Cond) {
Reid Spencer579dca12007-01-12 04:24:46 +0000315 BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue());
Devang Patel29d3dd82010-06-23 23:55:51 +0000316 VMap[OldTI] = BranchInst::Create(Dest, NewBB);
Chris Lattner67ef2412007-03-02 03:11:20 +0000317 ToClone.push_back(Dest);
Chris Lattner35033ef2006-06-01 19:19:23 +0000318 TerminatorDone = true;
319 }
320 }
321 } else if (const SwitchInst *SI = dyn_cast<SwitchInst>(OldTI)) {
322 // If switching on a value known constant in the caller.
323 ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition());
Rafael Espindola6688c4a2010-10-13 02:08:17 +0000324 if (Cond == 0) { // Or known constant after constant prop in the callee...
325 Value *V = VMap[SI->getCondition()];
326 Cond = dyn_cast_or_null<ConstantInt>(V);
327 }
Chris Lattner35033ef2006-06-01 19:19:23 +0000328 if (Cond) { // Constant fold to uncond branch!
Stepan Dyatkovskiyc10fa6c2012-03-08 07:06:20 +0000329 SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond);
330 BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
Devang Patel29d3dd82010-06-23 23:55:51 +0000331 VMap[OldTI] = BranchInst::Create(Dest, NewBB);
Chris Lattner67ef2412007-03-02 03:11:20 +0000332 ToClone.push_back(Dest);
Chris Lattner35033ef2006-06-01 19:19:23 +0000333 TerminatorDone = true;
334 }
335 }
336
337 if (!TerminatorDone) {
Nick Lewycky67760642009-09-27 07:38:41 +0000338 Instruction *NewInst = OldTI->clone();
Chris Lattner35033ef2006-06-01 19:19:23 +0000339 if (OldTI->hasName())
340 NewInst->setName(OldTI->getName()+NameSuffix);
341 NewBB->getInstList().push_back(NewInst);
Devang Patel29d3dd82010-06-23 23:55:51 +0000342 VMap[OldTI] = NewInst; // Add instruction map to value.
Chris Lattner35033ef2006-06-01 19:19:23 +0000343
344 // Recursively clone any reachable successor blocks.
345 const TerminatorInst *TI = BB->getTerminator();
346 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
Chris Lattner67ef2412007-03-02 03:11:20 +0000347 ToClone.push_back(TI->getSuccessor(i));
Chris Lattner35033ef2006-06-01 19:19:23 +0000348 }
349
Chris Lattner83f03bf2006-05-27 01:22:24 +0000350 if (CodeInfo) {
351 CodeInfo->ContainsCalls |= hasCalls;
Chris Lattner83f03bf2006-05-27 01:22:24 +0000352 CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
353 CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
354 BB != &BB->getParent()->front();
355 }
Chris Lattner83f03bf2006-05-27 01:22:24 +0000356}
357
Chris Lattner83f03bf2006-05-27 01:22:24 +0000358/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
359/// except that it does some simple constant prop and DCE on the fly. The
360/// effect of this is to copy significantly less code in cases where (for
361/// example) a function call with constant arguments is inlined, and those
362/// constant arguments cause a significant amount of code in the callee to be
Duncan Sandsdc024672007-11-27 13:23:08 +0000363/// dead. Since this doesn't produce an exact copy of the input, it can't be
Chris Lattner83f03bf2006-05-27 01:22:24 +0000364/// used for things like CloneFunction or CloneModule.
365void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
Devang Patel774cca72010-06-24 00:00:42 +0000366 ValueToValueMapTy &VMap,
Dan Gohman6cb8c232010-08-26 15:41:53 +0000367 bool ModuleLevelChanges,
Chris Lattnerec1bea02009-08-27 04:02:30 +0000368 SmallVectorImpl<ReturnInst*> &Returns,
Chris Lattner83f03bf2006-05-27 01:22:24 +0000369 const char *NameSuffix,
Chris Lattner1dfdf822007-01-30 23:22:39 +0000370 ClonedCodeInfo *CodeInfo,
Micah Villmow3574eca2012-10-08 16:38:25 +0000371 const DataLayout *TD,
Devang Patel53bb5c92009-11-10 23:06:00 +0000372 Instruction *TheCall) {
Chris Lattner83f03bf2006-05-27 01:22:24 +0000373 assert(NameSuffix && "NameSuffix cannot be null!");
374
375#ifndef NDEBUG
Jeff Cohend41b30d2006-11-05 19:31:28 +0000376 for (Function::const_arg_iterator II = OldFunc->arg_begin(),
377 E = OldFunc->arg_end(); II != E; ++II)
Devang Patel29d3dd82010-06-23 23:55:51 +0000378 assert(VMap.count(II) && "No mapping from source argument specified!");
Chris Lattner83f03bf2006-05-27 01:22:24 +0000379#endif
Duncan Sands28c3cff2008-05-26 19:58:59 +0000380
Dan Gohman6cb8c232010-08-26 15:41:53 +0000381 PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
Chandler Carruth6bbab862012-04-06 01:11:52 +0000382 NameSuffix, CodeInfo, TD);
Chris Lattner83f03bf2006-05-27 01:22:24 +0000383
384 // Clone the entry block, and anything recursively reachable from it.
Chris Lattner67ef2412007-03-02 03:11:20 +0000385 std::vector<const BasicBlock*> CloneWorklist;
386 CloneWorklist.push_back(&OldFunc->getEntryBlock());
387 while (!CloneWorklist.empty()) {
388 const BasicBlock *BB = CloneWorklist.back();
389 CloneWorklist.pop_back();
390 PFC.CloneBlock(BB, CloneWorklist);
391 }
Chris Lattner83f03bf2006-05-27 01:22:24 +0000392
393 // Loop over all of the basic blocks in the old function. If the block was
394 // reachable, we have cloned it and the old block is now in the value map:
395 // insert it into the new function in the right order. If not, ignore it.
396 //
Chris Lattner35033ef2006-06-01 19:19:23 +0000397 // Defer PHI resolution until rest of function is resolved.
Chris Lattnerec1bea02009-08-27 04:02:30 +0000398 SmallVector<const PHINode*, 16> PHIToResolve;
Chris Lattner83f03bf2006-05-27 01:22:24 +0000399 for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
400 BI != BE; ++BI) {
Rafael Espindola6688c4a2010-10-13 02:08:17 +0000401 Value *V = VMap[BI];
402 BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
Chris Lattner83f03bf2006-05-27 01:22:24 +0000403 if (NewBB == 0) continue; // Dead block.
Chris Lattner35033ef2006-06-01 19:19:23 +0000404
Chris Lattner83f03bf2006-05-27 01:22:24 +0000405 // Add the new block to the new function.
406 NewFunc->getBasicBlockList().push_back(NewBB);
Devang Patel53bb5c92009-11-10 23:06:00 +0000407
Chris Lattner83f03bf2006-05-27 01:22:24 +0000408 // Handle PHI nodes specially, as we have to remove references to dead
409 // blocks.
Chandler Carruthd54f9a42012-03-25 04:03:40 +0000410 for (BasicBlock::const_iterator I = BI->begin(), E = BI->end(); I != E; ++I)
411 if (const PHINode *PN = dyn_cast<PHINode>(I))
412 PHIToResolve.push_back(PN);
413 else
414 break;
415
416 // Finally, remap the terminator instructions, as those can't be remapped
417 // until all BBs are mapped.
418 RemapInstruction(NewBB->getTerminator(), VMap,
419 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
Chris Lattner83f03bf2006-05-27 01:22:24 +0000420 }
Chris Lattner35033ef2006-06-01 19:19:23 +0000421
422 // Defer PHI resolution until rest of function is resolved, PHI resolution
423 // requires the CFG to be up-to-date.
424 for (unsigned phino = 0, e = PHIToResolve.size(); phino != e; ) {
425 const PHINode *OPN = PHIToResolve[phino];
Chris Lattner35033ef2006-06-01 19:19:23 +0000426 unsigned NumPreds = OPN->getNumIncomingValues();
Chris Lattner35033ef2006-06-01 19:19:23 +0000427 const BasicBlock *OldBB = OPN->getParent();
Devang Patel29d3dd82010-06-23 23:55:51 +0000428 BasicBlock *NewBB = cast<BasicBlock>(VMap[OldBB]);
Chris Lattner35033ef2006-06-01 19:19:23 +0000429
430 // Map operands for blocks that are live and remove operands for blocks
431 // that are dead.
432 for (; phino != PHIToResolve.size() &&
433 PHIToResolve[phino]->getParent() == OldBB; ++phino) {
434 OPN = PHIToResolve[phino];
Devang Patel29d3dd82010-06-23 23:55:51 +0000435 PHINode *PN = cast<PHINode>(VMap[OPN]);
Chris Lattner35033ef2006-06-01 19:19:23 +0000436 for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
Rafael Espindola6688c4a2010-10-13 02:08:17 +0000437 Value *V = VMap[PN->getIncomingBlock(pred)];
Chris Lattnerb5fa5fc2011-01-08 08:15:20 +0000438 if (BasicBlock *MappedBlock = cast_or_null<BasicBlock>(V)) {
Owen Anderson0a205a42009-07-05 22:41:43 +0000439 Value *InVal = MapValue(PN->getIncomingValue(pred),
Chris Lattnerb5fa5fc2011-01-08 08:15:20 +0000440 VMap,
441 ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
Chris Lattner35033ef2006-06-01 19:19:23 +0000442 assert(InVal && "Unknown input value?");
443 PN->setIncomingValue(pred, InVal);
444 PN->setIncomingBlock(pred, MappedBlock);
445 } else {
446 PN->removeIncomingValue(pred, false);
447 --pred, --e; // Revisit the next entry.
448 }
449 }
450 }
451
452 // The loop above has removed PHI entries for those blocks that are dead
453 // and has updated others. However, if a block is live (i.e. copied over)
454 // but its terminator has been changed to not go to this block, then our
455 // phi nodes will have invalid entries. Update the PHI nodes in this
456 // case.
457 PHINode *PN = cast<PHINode>(NewBB->begin());
458 NumPreds = std::distance(pred_begin(NewBB), pred_end(NewBB));
459 if (NumPreds != PN->getNumIncomingValues()) {
460 assert(NumPreds < PN->getNumIncomingValues());
461 // Count how many times each predecessor comes to this block.
462 std::map<BasicBlock*, unsigned> PredCount;
463 for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB);
464 PI != E; ++PI)
465 --PredCount[*PI];
466
467 // Figure out how many entries to remove from each PHI.
468 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
469 ++PredCount[PN->getIncomingBlock(i)];
470
471 // At this point, the excess predecessor entries are positive in the
472 // map. Loop over all of the PHIs and remove excess predecessor
473 // entries.
474 BasicBlock::iterator I = NewBB->begin();
475 for (; (PN = dyn_cast<PHINode>(I)); ++I) {
476 for (std::map<BasicBlock*, unsigned>::iterator PCI =PredCount.begin(),
477 E = PredCount.end(); PCI != E; ++PCI) {
478 BasicBlock *Pred = PCI->first;
479 for (unsigned NumToRemove = PCI->second; NumToRemove; --NumToRemove)
480 PN->removeIncomingValue(Pred, false);
481 }
482 }
483 }
484
485 // If the loops above have made these phi nodes have 0 or 1 operand,
486 // replace them with undef or the input value. We must do this for
487 // correctness, because 0-operand phis are not valid.
488 PN = cast<PHINode>(NewBB->begin());
489 if (PN->getNumIncomingValues() == 0) {
490 BasicBlock::iterator I = NewBB->begin();
491 BasicBlock::const_iterator OldI = OldBB->begin();
492 while ((PN = dyn_cast<PHINode>(I++))) {
Owen Anderson9e9a0d52009-07-30 23:03:37 +0000493 Value *NV = UndefValue::get(PN->getType());
Chris Lattner35033ef2006-06-01 19:19:23 +0000494 PN->replaceAllUsesWith(NV);
Devang Patel29d3dd82010-06-23 23:55:51 +0000495 assert(VMap[OldI] == PN && "VMap mismatch");
496 VMap[OldI] = NV;
Chris Lattner35033ef2006-06-01 19:19:23 +0000497 PN->eraseFromParent();
498 ++OldI;
499 }
Chris Lattner35033ef2006-06-01 19:19:23 +0000500 }
501 }
Chandler Carruthf8c8a9c2012-03-25 10:34:54 +0000502
503 // Make a second pass over the PHINodes now that all of them have been
504 // remapped into the new function, simplifying the PHINode and performing any
505 // recursive simplifications exposed. This will transparently update the
Chandler Carruthafff3302012-03-28 08:38:27 +0000506 // WeakVH in the VMap. Notably, we rely on that so that if we coalesce
Chandler Carruthf8c8a9c2012-03-25 10:34:54 +0000507 // two PHINodes, the iteration over the old PHIs remains valid, and the
508 // mapping will just map us to the new node (which may not even be a PHI
509 // node).
510 for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx)
511 if (PHINode *PN = dyn_cast<PHINode>(VMap[PHIToResolve[Idx]]))
512 recursivelySimplifyInstruction(PN, TD);
513
Chris Lattnera4646b62006-09-13 21:27:00 +0000514 // Now that the inlined function body has been fully constructed, go through
515 // and zap unconditional fall-through branches. This happen all the time when
516 // specializing code: code specialization turns conditional branches into
517 // uncond branches, and this code folds them.
Chandler Carruthafff3302012-03-28 08:38:27 +0000518 Function::iterator Begin = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]);
519 Function::iterator I = Begin;
Chris Lattnera4646b62006-09-13 21:27:00 +0000520 while (I != NewFunc->end()) {
Chandler Carruthafff3302012-03-28 08:38:27 +0000521 // Check if this block has become dead during inlining or other
522 // simplifications. Note that the first block will appear dead, as it has
523 // not yet been wired up properly.
524 if (I != Begin && (pred_begin(I) == pred_end(I) ||
525 I->getSinglePredecessor() == I)) {
526 BasicBlock *DeadBB = I++;
527 DeleteDeadBlock(DeadBB);
528 continue;
529 }
530
531 // We need to simplify conditional branches and switches with a constant
532 // operand. We try to prune these out when cloning, but if the
533 // simplification required looking through PHI nodes, those are only
534 // available after forming the full basic block. That may leave some here,
535 // and we still want to prune the dead code as early as possible.
536 ConstantFoldTerminator(I);
537
Chris Lattnera4646b62006-09-13 21:27:00 +0000538 BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
539 if (!BI || BI->isConditional()) { ++I; continue; }
540
541 BasicBlock *Dest = BI->getSuccessor(0);
Chandler Carruthf8c8a9c2012-03-25 10:34:54 +0000542 if (!Dest->getSinglePredecessor()) {
Chris Lattner8e8eda72007-02-01 18:48:38 +0000543 ++I; continue;
544 }
Chandler Carruthf8c8a9c2012-03-25 10:34:54 +0000545
546 // We shouldn't be able to get single-entry PHI nodes here, as instsimplify
547 // above should have zapped all of them..
548 assert(!isa<PHINode>(Dest->begin()));
549
Chris Lattnera4646b62006-09-13 21:27:00 +0000550 // We know all single-entry PHI nodes in the inlined function have been
551 // removed, so we just need to splice the blocks.
552 BI->eraseFromParent();
553
Eric Christophere59fbc02011-06-23 06:24:52 +0000554 // Make all PHI nodes that referred to Dest now refer to I as their source.
555 Dest->replaceAllUsesWith(I);
556
Jay Foad95c3e482011-06-23 09:09:15 +0000557 // Move all the instructions in the succ to the pred.
558 I->getInstList().splice(I->end(), Dest->getInstList());
559
Chris Lattnera4646b62006-09-13 21:27:00 +0000560 // Remove the dest block.
561 Dest->eraseFromParent();
562
563 // Do not increment I, iteratively merge all things this block branches to.
564 }
Chandler Carruth9ceebb72012-04-06 17:21:31 +0000565
566 // Make a final pass over the basic blocks from theh old function to gather
567 // any return instructions which survived folding. We have to do this here
568 // because we can iteratively remove and merge returns above.
569 for (Function::iterator I = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]),
570 E = NewFunc->end();
571 I != E; ++I)
572 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator()))
573 Returns.push_back(RI);
Chris Lattner83f03bf2006-05-27 01:22:24 +0000574}