//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/Cloning.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Instructions.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/GlobalVariable.h"
-#include "llvm/Function.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Support/CFG.h"
-#include "llvm/Transforms/Utils/ValueMapper.h"
-#include "llvm/Analysis/ConstantFolding.h"
-#include "llvm/Analysis/DebugInfo.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/ValueMapper.h"
#include <map>
+#include <set>
using namespace llvm;
// CloneBasicBlock - See comments in Cloning.h
BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
- DenseMap<const Value*, Value*> &ValueMap,
- const char *NameSuffix, Function *F,
+ ValueToValueMapTy &VMap,
+ const Twine &NameSuffix, Function *F,
ClonedCodeInfo *CodeInfo) {
BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
if (II->hasName())
NewInst->setName(II->getName()+NameSuffix);
NewBB->getInstList().push_back(NewInst);
- ValueMap[II] = NewInst; // Add instruction map to value.
+ VMap[II] = NewInst; // Add instruction map to value.
hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
if (CodeInfo) {
CodeInfo->ContainsCalls |= hasCalls;
- CodeInfo->ContainsUnwinds |= isa<UnwindInst>(BB->getTerminator());
CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
BB != &BB->getParent()->getEntryBlock();
}
// Clone OldFunc into NewFunc, transforming the old arguments into references to
-// ArgMap values.
+// VMap values.
//
void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
- DenseMap<const Value*, Value*> &ValueMap,
+ ValueToValueMapTy &VMap,
+ bool ModuleLevelChanges,
SmallVectorImpl<ReturnInst*> &Returns,
- const char *NameSuffix, ClonedCodeInfo *CodeInfo) {
+ const char *NameSuffix, ClonedCodeInfo *CodeInfo,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
assert(NameSuffix && "NameSuffix cannot be null!");
#ifndef NDEBUG
for (Function::const_arg_iterator I = OldFunc->arg_begin(),
E = OldFunc->arg_end(); I != E; ++I)
- assert(ValueMap.count(I) && "No mapping from source argument specified!");
+ assert(VMap.count(I) && "No mapping from source argument specified!");
#endif
- // Clone any attributes.
- if (NewFunc->arg_size() == OldFunc->arg_size())
- NewFunc->copyAttributesFrom(OldFunc);
- else {
- //Some arguments were deleted with the ValueMap. Copy arguments one by one
- for (Function::const_arg_iterator I = OldFunc->arg_begin(),
- E = OldFunc->arg_end(); I != E; ++I)
- if (Argument* Anew = dyn_cast<Argument>(ValueMap[I]))
- Anew->addAttr( OldFunc->getAttributes()
- .getParamAttributes(I->getArgNo() + 1));
- NewFunc->setAttributes(NewFunc->getAttributes()
- .addAttr(0, OldFunc->getAttributes()
- .getRetAttributes()));
- NewFunc->setAttributes(NewFunc->getAttributes()
- .addAttr(~0, OldFunc->getAttributes()
- .getFnAttributes()));
+ // Copy all attributes other than those stored in the AttributeSet. We need
+ // to remap the parameter indices of the AttributeSet.
+ AttributeSet NewAttrs = NewFunc->getAttributes();
+ NewFunc->copyAttributesFrom(OldFunc);
+ NewFunc->setAttributes(NewAttrs);
+
+ AttributeSet OldAttrs = OldFunc->getAttributes();
+ // Clone any argument attributes that are present in the VMap.
+ for (const Argument &OldArg : OldFunc->args())
+ if (Argument *NewArg = dyn_cast<Argument>(VMap[&OldArg])) {
+ AttributeSet attrs =
+ OldAttrs.getParamAttributes(OldArg.getArgNo() + 1);
+ if (attrs.getNumSlots() > 0)
+ NewArg->addAttr(attrs);
+ }
- }
+ NewFunc->setAttributes(
+ NewFunc->getAttributes()
+ .addAttributes(NewFunc->getContext(), AttributeSet::ReturnIndex,
+ OldAttrs.getRetAttributes())
+ .addAttributes(NewFunc->getContext(), AttributeSet::FunctionIndex,
+ OldAttrs.getFnAttributes()));
// Loop over all of the basic blocks in the function, cloning them as
// appropriate. Note that we save BE this way in order to handle cloning of
const BasicBlock &BB = *BI;
// Create a new basic block and copy instructions into it!
- BasicBlock *CBB = CloneBasicBlock(&BB, ValueMap, NameSuffix, NewFunc,
- CodeInfo);
- ValueMap[&BB] = CBB; // Add basic block mapping.
+ BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo);
+
+ // Add basic block mapping.
+ VMap[&BB] = CBB;
+
+ // It is only legal to clone a function if a block address within that
+ // function is never referenced outside of the function. Given that, we
+ // want to map block addresses from the old function to block addresses in
+ // the clone. (This is different from the generic ValueMapper
+ // implementation, which generates an invalid blockaddress when
+ // cloning a function.)
+ if (BB.hasAddressTaken()) {
+ Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
+ const_cast<BasicBlock*>(&BB));
+ VMap[OldBBAddr] = BlockAddress::get(NewFunc, CBB);
+ }
+ // Note return instructions for the caller.
if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
Returns.push_back(RI);
}
// Loop over all of the instructions in the function, fixing up operand
- // references as we go. This uses ValueMap to do all the hard work.
- //
- for (Function::iterator BB = cast<BasicBlock>(ValueMap[OldFunc->begin()]),
+ // references as we go. This uses VMap to do all the hard work.
+ for (Function::iterator BB = cast<BasicBlock>(VMap[OldFunc->begin()]),
BE = NewFunc->end(); BB != BE; ++BB)
// Loop over all instructions, fixing each one as we find it...
for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II)
- RemapInstruction(II, ValueMap);
+ RemapInstruction(II, VMap,
+ ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
+ TypeMapper, Materializer);
+}
+
+// Find the MDNode which corresponds to the DISubprogram data that described F.
+static MDNode* FindSubprogram(const Function *F, DebugInfoFinder &Finder) {
+ for (DISubprogram Subprogram : Finder.subprograms()) {
+ if (Subprogram.describes(F)) return Subprogram;
+ }
+ return nullptr;
+}
+
+// Add an operand to an existing MDNode. The new operand will be added at the
+// back of the operand list.
+static void AddOperand(MDNode *Node, Value *Operand) {
+ SmallVector<Value*, 16> Operands;
+ for (unsigned i = 0; i < Node->getNumOperands(); i++) {
+ Operands.push_back(Node->getOperand(i));
+ }
+ Operands.push_back(Operand);
+ MDNode *NewNode = MDNode::get(Node->getContext(), Operands);
+ Node->replaceAllUsesWith(NewNode);
+}
+
+// Clone the module-level debug info associated with OldFunc. The cloned data
+// will point to NewFunc instead.
+static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
+ ValueToValueMapTy &VMap) {
+ DebugInfoFinder Finder;
+ Finder.processModule(*OldFunc->getParent());
+
+ const MDNode *OldSubprogramMDNode = FindSubprogram(OldFunc, Finder);
+ if (!OldSubprogramMDNode) return;
+
+ // Ensure that OldFunc appears in the map.
+ // (if it's already there it must point to NewFunc anyway)
+ VMap[OldFunc] = NewFunc;
+ DISubprogram NewSubprogram(MapValue(OldSubprogramMDNode, VMap));
+
+ for (DICompileUnit CU : Finder.compile_units()) {
+ DIArray Subprograms(CU.getSubprograms());
+
+ // If the compile unit's function list contains the old function, it should
+ // also contain the new one.
+ for (unsigned i = 0; i < Subprograms.getNumElements(); i++) {
+ if ((MDNode*)Subprograms.getElement(i) == OldSubprogramMDNode) {
+ AddOperand(Subprograms, NewSubprogram);
+ }
+ }
+ }
}
/// CloneFunction - Return a copy of the specified function, but without
/// embedding the function into another module. Also, any references specified
-/// in the ValueMap are changed to refer to their mapped value instead of the
-/// original one. If any of the arguments to the function are in the ValueMap,
-/// the arguments are deleted from the resultant function. The ValueMap is
+/// in the VMap are changed to refer to their mapped value instead of the
+/// original one. If any of the arguments to the function are in the VMap,
+/// the arguments are deleted from the resultant function. The VMap is
/// updated to include mappings from all of the instructions and basicblocks in
/// the function from their old to new values.
///
-Function *llvm::CloneFunction(const Function *F,
- DenseMap<const Value*, Value*> &ValueMap,
+Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap,
+ bool ModuleLevelChanges,
ClonedCodeInfo *CodeInfo) {
- std::vector<const Type*> ArgTypes;
+ std::vector<Type*> ArgTypes;
// The user might be deleting arguments to the function by specifying them in
- // the ValueMap. If so, we need to not add the arguments to the arg ty vector
+ // the VMap. If so, we need to not add the arguments to the arg ty vector
//
for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
I != E; ++I)
- if (ValueMap.count(I) == 0) // Haven't mapped the argument to anything yet?
+ if (VMap.count(I) == 0) // Haven't mapped the argument to anything yet?
ArgTypes.push_back(I->getType());
// Create a new function type...
Function::arg_iterator DestI = NewF->arg_begin();
for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
I != E; ++I)
- if (ValueMap.count(I) == 0) { // Is this argument preserved?
+ if (VMap.count(I) == 0) { // Is this argument preserved?
DestI->setName(I->getName()); // Copy the name over...
- ValueMap[I] = DestI++; // Add mapping to ValueMap
+ VMap[I] = DestI++; // Add mapping to VMap
}
+ if (ModuleLevelChanges)
+ CloneDebugInfoMetadata(NewF, F, VMap);
+
SmallVector<ReturnInst*, 8> Returns; // Ignore returns cloned.
- CloneFunctionInto(NewF, F, ValueMap, Returns, "", CodeInfo);
+ CloneFunctionInto(NewF, F, VMap, ModuleLevelChanges, Returns, "", CodeInfo);
return NewF;
}
struct PruningFunctionCloner {
Function *NewFunc;
const Function *OldFunc;
- DenseMap<const Value*, Value*> &ValueMap;
- SmallVectorImpl<ReturnInst*> &Returns;
+ ValueToValueMapTy &VMap;
+ bool ModuleLevelChanges;
const char *NameSuffix;
ClonedCodeInfo *CodeInfo;
- const TargetData *TD;
- Value *DbgFnStart;
+ const DataLayout *DL;
public:
PruningFunctionCloner(Function *newFunc, const Function *oldFunc,
- DenseMap<const Value*, Value*> &valueMap,
- SmallVectorImpl<ReturnInst*> &returns,
+ ValueToValueMapTy &valueMap,
+ bool moduleLevelChanges,
const char *nameSuffix,
ClonedCodeInfo *codeInfo,
- const TargetData *td)
- : NewFunc(newFunc), OldFunc(oldFunc), ValueMap(valueMap), Returns(returns),
- NameSuffix(nameSuffix), CodeInfo(codeInfo), TD(td), DbgFnStart(NULL) {
+ const DataLayout *DL)
+ : NewFunc(newFunc), OldFunc(oldFunc),
+ VMap(valueMap), ModuleLevelChanges(moduleLevelChanges),
+ NameSuffix(nameSuffix), CodeInfo(codeInfo), DL(DL) {
}
- /// CloneBlock - The specified block is found to be reachable, clone it and
- /// anything that it can reach.
+ /// CloneBlock - The specified block is found to be reachable, so clone it
+ /// into NewBB.
+ /// ToClone is the vector of actually cloned blocks.
+ /// OrigBBs is the set of all blocks reacheable from the entry block.
+ /// It contains the block candidates and makes sure each block
+ /// is cloned at most once.
void CloneBlock(const BasicBlock *BB,
- std::vector<const BasicBlock*> &ToClone);
-
- public:
- /// ConstantFoldMappedInstruction - Constant fold the specified instruction,
- /// mapping its operands through ValueMap if they are available.
- Constant *ConstantFoldMappedInstruction(const Instruction *I);
+ BasicBlock *NewBB,
+ std::vector<const BasicBlock *> &ToClone,
+ std::set<const BasicBlock *> &OrigBBs);
};
}
-/// CloneBlock - The specified block is found to be reachable, clone it and
-/// anything that it can reach.
+/// CloneBlock - The specified block is found to be reachable, so clone it
+/// into NewBB.
+/// ToClone is the vector of actually cloned blocks.
+/// OrigBBs is the set of all blocks reacheable from the entry block.
+/// It contains the block candidates and makes sure each block
+/// is cloned at most once.
void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
- std::vector<const BasicBlock*> &ToClone){
- Value *&BBEntry = ValueMap[BB];
-
- // Have we already cloned this block?
- if (BBEntry) return;
+ BasicBlock *NewBB,
+ std::vector<const BasicBlock *> &ToClone,
+ std::set<const BasicBlock *> &OrigBBs) {
+ // Remove BB from list of blocks to clone.
+ // When it was not in the list, it has been cloned already, so
+ // don't clone again.
+ if (!OrigBBs.erase(BB)) return;
+
// Nope, clone it now.
- BasicBlock *NewBB;
- BBEntry = NewBB = BasicBlock::Create(BB->getContext());
- if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
// loop doesn't include the terminator.
for (BasicBlock::const_iterator II = BB->begin(), IE = --BB->end();
II != IE; ++II) {
- // If this instruction constant folds, don't bother cloning the instruction,
- // instead, just add the constant to the value map.
- if (Constant *C = ConstantFoldMappedInstruction(II)) {
- ValueMap[II] = C;
- continue;
- }
+ Instruction *NewInst = II->clone();
- // Do not clone llvm.dbg.region.end. It will be adjusted by the inliner.
- if (const DbgFuncStartInst *DFSI = dyn_cast<DbgFuncStartInst>(II)) {
- if (DbgFnStart == NULL) {
- DISubprogram SP(DFSI->getSubprogram());
- if (SP.describes(BB->getParent()))
- DbgFnStart = DFSI->getSubprogram();
- }
- }
- if (const DbgRegionEndInst *DREIS = dyn_cast<DbgRegionEndInst>(II)) {
- if (DREIS->getContext() == DbgFnStart)
+ // Eagerly remap operands to the newly cloned instruction, except for PHI
+ // nodes for which we defer processing until we update the CFG.
+ if (!isa<PHINode>(NewInst)) {
+ RemapInstruction(NewInst, VMap,
+ ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
+
+ // If we can simplify this instruction to some other value, simply add
+ // a mapping to that value rather than inserting a new instruction into
+ // the basic block.
+ if (Value *V = SimplifyInstruction(NewInst, DL)) {
+ // On the off-chance that this simplifies to an instruction in the old
+ // function, map it back into the new function.
+ if (Value *MappedV = VMap.lookup(V))
+ V = MappedV;
+
+ VMap[II] = V;
+ delete NewInst;
continue;
+ }
}
-
- Instruction *NewInst = II->clone();
+
if (II->hasName())
NewInst->setName(II->getName()+NameSuffix);
+ VMap[II] = NewInst; // Add instruction map to value.
NewBB->getInstList().push_back(NewInst);
- ValueMap[II] = NewInst; // Add instruction map to value.
-
hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
if (isa<ConstantInt>(AI->getArraySize()))
// If the condition was a known constant in the callee...
ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition());
// Or is a known constant in the caller...
- if (Cond == 0)
- Cond = dyn_cast_or_null<ConstantInt>(ValueMap[BI->getCondition()]);
+ if (!Cond) {
+ Value *V = VMap[BI->getCondition()];
+ Cond = dyn_cast_or_null<ConstantInt>(V);
+ }
// Constant fold to uncond branch!
if (Cond) {
BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue());
- ValueMap[OldTI] = BranchInst::Create(Dest, NewBB);
+ VMap[OldTI] = BranchInst::Create(Dest, NewBB);
ToClone.push_back(Dest);
TerminatorDone = true;
}
} else if (const SwitchInst *SI = dyn_cast<SwitchInst>(OldTI)) {
// If switching on a value known constant in the caller.
ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition());
- if (Cond == 0) // Or known constant after constant prop in the callee...
- Cond = dyn_cast_or_null<ConstantInt>(ValueMap[SI->getCondition()]);
+ if (!Cond) { // Or known constant after constant prop in the callee...
+ Value *V = VMap[SI->getCondition()];
+ Cond = dyn_cast_or_null<ConstantInt>(V);
+ }
if (Cond) { // Constant fold to uncond branch!
- BasicBlock *Dest = SI->getSuccessor(SI->findCaseValue(Cond));
- ValueMap[OldTI] = BranchInst::Create(Dest, NewBB);
+ SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond);
+ BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
+ VMap[OldTI] = BranchInst::Create(Dest, NewBB);
ToClone.push_back(Dest);
TerminatorDone = true;
}
if (OldTI->hasName())
NewInst->setName(OldTI->getName()+NameSuffix);
NewBB->getInstList().push_back(NewInst);
- ValueMap[OldTI] = NewInst; // Add instruction map to value.
+ VMap[OldTI] = NewInst; // Add instruction map to value.
// Recursively clone any reachable successor blocks.
const TerminatorInst *TI = BB->getTerminator();
if (CodeInfo) {
CodeInfo->ContainsCalls |= hasCalls;
- CodeInfo->ContainsUnwinds |= isa<UnwindInst>(OldTI);
CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
BB != &BB->getParent()->front();
}
-
- if (ReturnInst *RI = dyn_cast<ReturnInst>(NewBB->getTerminator()))
- Returns.push_back(RI);
-}
-
-/// ConstantFoldMappedInstruction - Constant fold the specified instruction,
-/// mapping its operands through ValueMap if they are available.
-Constant *PruningFunctionCloner::
-ConstantFoldMappedInstruction(const Instruction *I) {
- SmallVector<Constant*, 8> Ops;
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
- if (Constant *Op = dyn_cast_or_null<Constant>(MapValue(I->getOperand(i),
- ValueMap)))
- Ops.push_back(Op);
- else
- return 0; // All operands not constant!
-
- if (const CmpInst *CI = dyn_cast<CmpInst>(I))
- return ConstantFoldCompareInstOperands(CI->getPredicate(), Ops[0], Ops[1],
- TD);
-
- if (const LoadInst *LI = dyn_cast<LoadInst>(I))
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0]))
- if (!LI->isVolatile() && CE->getOpcode() == Instruction::GetElementPtr)
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(CE->getOperand(0)))
- if (GV->isConstant() && GV->hasDefinitiveInitializer())
- return ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(),
- CE);
-
- return ConstantFoldInstOperands(I->getOpcode(), I->getType(), &Ops[0],
- Ops.size(), TD);
-}
-
-static MDNode *UpdateInlinedAtInfo(MDNode *InsnMD, MDNode *TheCallMD,
- LLVMContext &Context) {
- DILocation ILoc(InsnMD);
- if (ILoc.isNull()) return InsnMD;
-
- DILocation CallLoc(TheCallMD);
- if (CallLoc.isNull()) return InsnMD;
-
- DILocation OrigLocation = ILoc.getOrigLocation();
- MDNode *NewLoc = TheCallMD;
- if (!OrigLocation.isNull())
- NewLoc = UpdateInlinedAtInfo(OrigLocation.getNode(), TheCallMD, Context);
-
- SmallVector<Value *, 4> MDVs;
- MDVs.push_back(InsnMD->getElement(0)); // Line
- MDVs.push_back(InsnMD->getElement(1)); // Col
- MDVs.push_back(InsnMD->getElement(2)); // Scope
- MDVs.push_back(NewLoc);
- return MDNode::get(Context, MDVs.data(), MDVs.size());
}
/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
/// dead. Since this doesn't produce an exact copy of the input, it can't be
/// used for things like CloneFunction or CloneModule.
void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
- DenseMap<const Value*, Value*> &ValueMap,
+ ValueToValueMapTy &VMap,
+ bool ModuleLevelChanges,
SmallVectorImpl<ReturnInst*> &Returns,
const char *NameSuffix,
ClonedCodeInfo *CodeInfo,
- const TargetData *TD,
+ const DataLayout *DL,
Instruction *TheCall) {
assert(NameSuffix && "NameSuffix cannot be null!");
-
+
#ifndef NDEBUG
for (Function::const_arg_iterator II = OldFunc->arg_begin(),
E = OldFunc->arg_end(); II != E; ++II)
- assert(ValueMap.count(II) && "No mapping from source argument specified!");
+ assert(VMap.count(II) && "No mapping from source argument specified!");
#endif
- PruningFunctionCloner PFC(NewFunc, OldFunc, ValueMap, Returns,
- NameSuffix, CodeInfo, TD);
+ PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
+ NameSuffix, CodeInfo, DL);
- // Clone the entry block, and anything recursively reachable from it.
+ // Since all BB address references need to be known before block-by-block
+ // processing, we need to create all reachable blocks before processing
+ // them for instruction cloning and pruning. Some of these blocks may
+ // be removed due to later pruning.
std::vector<const BasicBlock*> CloneWorklist;
+ //
+ // OrigBBs consists of all blocks reachable from the entry
+ // block.
+ // This list will be pruned down by the CloneFunction() due to two
+ // two optimizations:
+ // First, when a conditional branch target is known at compile-time,
+ // only the actual branch destination block needs to be cloned.
+ // Second, when a switch statement target is known at compile-time,
+ // only the actual case statement needs to be cloned.
+ std::set<const BasicBlock *> OrigBBs;
+
CloneWorklist.push_back(&OldFunc->getEntryBlock());
while (!CloneWorklist.empty()) {
const BasicBlock *BB = CloneWorklist.back();
CloneWorklist.pop_back();
- PFC.CloneBlock(BB, CloneWorklist);
+
+ // Don't revisit blocks.
+ if (VMap.count(BB))
+ continue;
+
+ BasicBlock *NewBB = BasicBlock::Create(BB->getContext());
+ if (BB->hasName())
+ NewBB->setName(BB->getName() + NameSuffix);
+
+ // It is legal to clone a function when a block address within that
+ // function is never escapes outside of the function. Given that, we
+ // want to map block addresses from the old function to block addresses in
+ // the clone. (This is different from the generic ValueMapper
+ // implementation, which generates an invalid block address when
+ // cloning a function.)
+ // Note the current escape address does not catch all legal cases: even
+ // when all block addresses taken are local and the function has the
+ // always_inline attribute due to the indirect branch inlining is
+ // suppressed.
+ // Note that we don't need to fix the mapping for unreachable blocks;
+ // the default mapping there is safe.
+ if (BB->hasAddressTaken()) {
+ Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
+ const_cast<BasicBlock*>(BB));
+ VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
+ }
+
+ OrigBBs.insert(BB);
+ VMap[BB] = NewBB;
+ // Iterate over all possible successors and add them to the CloneWorklist.
+ const TerminatorInst *Term = BB->getTerminator();
+ for (unsigned i = 0, e = Term->getNumSuccessors(); i != e; ++i) {
+ BasicBlock *Succ = Term->getSuccessor(i);
+ CloneWorklist.push_back(Succ);
+ }
}
-
+
+ // Now, fill only the reachable blocks with the cloned contents
+ // of the originals.
+ assert(CloneWorklist.empty() && "Dirty worklist before re-use\n");
+ CloneWorklist.push_back(&OldFunc->getEntryBlock());
+ while (!CloneWorklist.empty()) {
+ const BasicBlock *BB = CloneWorklist.back();
+ CloneWorklist.pop_back();
+ PFC.CloneBlock(BB, cast<BasicBlock>(VMap[BB]), CloneWorklist,
+ OrigBBs);
+ }
+
+ // FIXME: Delete BB's that were created but have been pruned.
+ // Actual cloning may have found pruning opportunities since
+ // branch or switch statement target may have been known at compile-time.
+ // Alternatively we could write a routine CloneFunction and add a) a
+ // parameter to actually do the cloning and b) a return parameter that
+ // gives a list of blocks that need to be cloned also. Then we could
+ // call CloneFunction when we collect the blocks to clone, but suppress
+ // cloning. And then actually *do* the cloning in the while loop above. Then
+ // the cleanup here would become redundant, and so would be the OrigBBs.
+ for (std::set<const BasicBlock *>::iterator Oi = OrigBBs.begin(),
+ Oe = OrigBBs.end(); Oi != Oe; ++Oi) {
+ const BasicBlock *Orig = *Oi;
+ BasicBlock *NewBB = cast<BasicBlock>(VMap[Orig]);
+ delete NewBB;
+ VMap[Orig] = 0;
+ }
+
// Loop over all of the basic blocks in the old function. If the block was
// reachable, we have cloned it and the old block is now in the value map:
// insert it into the new function in the right order. If not, ignore it.
SmallVector<const PHINode*, 16> PHIToResolve;
for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
BI != BE; ++BI) {
- BasicBlock *NewBB = cast_or_null<BasicBlock>(ValueMap[BI]);
- if (NewBB == 0) continue; // Dead block.
+ Value *V = VMap[BI];
+ BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
+ if (!NewBB)
+ continue; // Dead block.
// Add the new block to the new function.
NewFunc->getBasicBlockList().push_back(NewBB);
-
- // Loop over all of the instructions in the block, fixing up operand
- // references as we go. This uses ValueMap to do all the hard work.
- //
- BasicBlock::iterator I = NewBB->begin();
-
- LLVMContext &Context = OldFunc->getContext();
- unsigned DbgKind = Context.getMetadata().getMDKind("dbg");
- MDNode *TheCallMD = NULL;
- SmallVector<Value *, 4> MDVs;
- if (TheCall && TheCall->hasMetadata())
- TheCallMD = Context.getMetadata().getMD(DbgKind, TheCall);
-
+
// Handle PHI nodes specially, as we have to remove references to dead
// blocks.
- if (PHINode *PN = dyn_cast<PHINode>(I)) {
- // Skip over all PHI nodes, remembering them for later.
- BasicBlock::const_iterator OldI = BI->begin();
- for (; (PN = dyn_cast<PHINode>(I)); ++I, ++OldI) {
- if (I->hasMetadata())
- if (TheCallMD) {
- if (MDNode *IMD = Context.getMetadata().getMD(DbgKind, I)) {
- MDNode *NewMD = UpdateInlinedAtInfo(IMD, TheCallMD, Context);
- Context.getMetadata().addMD(DbgKind, NewMD, I);
- }
- } else
- // The cloned instruction has dbg info but the call instruction
- // does not have dbg info. Remove dbg info from cloned instruction.
- Context.getMetadata().removeMD(DbgKind, I);
- PHIToResolve.push_back(cast<PHINode>(OldI));
- }
- }
-
- // Otherwise, remap the rest of the instructions normally.
- for (; I != NewBB->end(); ++I) {
- if (I->hasMetadata())
- if (TheCallMD) {
- if (MDNode *IMD = Context.getMetadata().getMD(DbgKind, I)) {
- MDNode *NewMD = UpdateInlinedAtInfo(IMD, TheCallMD, Context);
- Context.getMetadata().addMD(DbgKind, NewMD, I);
- }
- } else
- // The cloned instruction has dbg info but the call instruction
- // does not have dbg info. Remove dbg info from cloned instruction.
- Context.getMetadata().removeMD(DbgKind, I);
-
- RemapInstruction(I, ValueMap);
- }
+ for (BasicBlock::const_iterator I = BI->begin(), E = BI->end(); I != E; ++I)
+ if (const PHINode *PN = dyn_cast<PHINode>(I))
+ PHIToResolve.push_back(PN);
+ else
+ break;
+
+ // Finally, remap the terminator instructions, as those can't be remapped
+ // until all BBs are mapped.
+ RemapInstruction(NewBB->getTerminator(), VMap,
+ ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
}
// Defer PHI resolution until rest of function is resolved, PHI resolution
const PHINode *OPN = PHIToResolve[phino];
unsigned NumPreds = OPN->getNumIncomingValues();
const BasicBlock *OldBB = OPN->getParent();
- BasicBlock *NewBB = cast<BasicBlock>(ValueMap[OldBB]);
+ BasicBlock *NewBB = cast<BasicBlock>(VMap[OldBB]);
// Map operands for blocks that are live and remove operands for blocks
// that are dead.
for (; phino != PHIToResolve.size() &&
PHIToResolve[phino]->getParent() == OldBB; ++phino) {
OPN = PHIToResolve[phino];
- PHINode *PN = cast<PHINode>(ValueMap[OPN]);
+ PHINode *PN = cast<PHINode>(VMap[OPN]);
for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
- if (BasicBlock *MappedBlock =
- cast_or_null<BasicBlock>(ValueMap[PN->getIncomingBlock(pred)])) {
+ Value *V = VMap[PN->getIncomingBlock(pred)];
+ if (BasicBlock *MappedBlock = cast_or_null<BasicBlock>(V)) {
Value *InVal = MapValue(PN->getIncomingValue(pred),
- ValueMap);
+ VMap,
+ ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
assert(InVal && "Unknown input value?");
PN->setIncomingValue(pred, InVal);
PN->setIncomingBlock(pred, MappedBlock);
while ((PN = dyn_cast<PHINode>(I++))) {
Value *NV = UndefValue::get(PN->getType());
PN->replaceAllUsesWith(NV);
- assert(ValueMap[OldI] == PN && "ValueMap mismatch");
- ValueMap[OldI] = NV;
+ assert(VMap[OldI] == PN && "VMap mismatch");
+ VMap[OldI] = NV;
PN->eraseFromParent();
++OldI;
}
}
- // NOTE: We cannot eliminate single entry phi nodes here, because of
- // ValueMap. Single entry phi nodes can have multiple ValueMap entries
- // pointing at them. Thus, deleting one would require scanning the ValueMap
- // to update any entries in it that would require that. This would be
- // really slow.
}
-
+
+ // Make a second pass over the PHINodes now that all of them have been
+ // remapped into the new function, simplifying the PHINode and performing any
+ // recursive simplifications exposed. This will transparently update the
+ // WeakVH in the VMap. Notably, we rely on that so that if we coalesce
+ // two PHINodes, the iteration over the old PHIs remains valid, and the
+ // mapping will just map us to the new node (which may not even be a PHI
+ // node).
+ for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx)
+ if (PHINode *PN = dyn_cast<PHINode>(VMap[PHIToResolve[Idx]]))
+ recursivelySimplifyInstruction(PN, DL);
+
// Now that the inlined function body has been fully constructed, go through
// and zap unconditional fall-through branches. This happen all the time when
// specializing code: code specialization turns conditional branches into
// uncond branches, and this code folds them.
- Function::iterator I = cast<BasicBlock>(ValueMap[&OldFunc->getEntryBlock()]);
+ Function::iterator Begin = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]);
+ Function::iterator I = Begin;
while (I != NewFunc->end()) {
+ // Check if this block has become dead during inlining or other
+ // simplifications. Note that the first block will appear dead, as it has
+ // not yet been wired up properly.
+ if (I != Begin && (pred_begin(I) == pred_end(I) ||
+ I->getSinglePredecessor() == I)) {
+ BasicBlock *DeadBB = I++;
+ DeleteDeadBlock(DeadBB);
+ continue;
+ }
+
+ // We need to simplify conditional branches and switches with a constant
+ // operand. We try to prune these out when cloning, but if the
+ // simplification required looking through PHI nodes, those are only
+ // available after forming the full basic block. That may leave some here,
+ // and we still want to prune the dead code as early as possible.
+ ConstantFoldTerminator(I);
+
BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
if (!BI || BI->isConditional()) { ++I; continue; }
- // Note that we can't eliminate uncond branches if the destination has
- // single-entry PHI nodes. Eliminating the single-entry phi nodes would
- // require scanning the ValueMap to update any entries that point to the phi
- // node.
BasicBlock *Dest = BI->getSuccessor(0);
- if (!Dest->getSinglePredecessor() || isa<PHINode>(Dest->begin())) {
+ if (!Dest->getSinglePredecessor()) {
++I; continue;
}
-
+
+ // We shouldn't be able to get single-entry PHI nodes here, as instsimplify
+ // above should have zapped all of them..
+ assert(!isa<PHINode>(Dest->begin()));
+
// We know all single-entry PHI nodes in the inlined function have been
// removed, so we just need to splice the blocks.
BI->eraseFromParent();
- // Move all the instructions in the succ to the pred.
- I->getInstList().splice(I->end(), Dest->getInstList());
-
// Make all PHI nodes that referred to Dest now refer to I as their source.
Dest->replaceAllUsesWith(I);
+ // Move all the instructions in the succ to the pred.
+ I->getInstList().splice(I->end(), Dest->getInstList());
+
// Remove the dest block.
Dest->eraseFromParent();
// Do not increment I, iteratively merge all things this block branches to.
}
+
+ // Make a final pass over the basic blocks from theh old function to gather
+ // any return instructions which survived folding. We have to do this here
+ // because we can iteratively remove and merge returns above.
+ for (Function::iterator I = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]),
+ E = NewFunc->end();
+ I != E; ++I)
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator()))
+ Returns.push_back(RI);
}
projects / oota-llvm.git / blobdiff