diff options
Diffstat (limited to 'contrib/llvm/lib/Transforms/IPO/GlobalOpt.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/IPO/GlobalOpt.cpp | 629 |
1 files changed, 390 insertions, 239 deletions
diff --git a/contrib/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/contrib/llvm/lib/Transforms/IPO/GlobalOpt.cpp index 5ffe15d..fd77369 100644 --- a/contrib/llvm/lib/Transforms/IPO/GlobalOpt.cpp +++ b/contrib/llvm/lib/Transforms/IPO/GlobalOpt.cpp @@ -28,6 +28,7 @@ #include "llvm/IR/Constants.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/Dominators.h" #include "llvm/IR/GetElementPtrTypeIterator.h" #include "llvm/IR/Instructions.h" #include "llvm/IR/IntrinsicInst.h" @@ -54,7 +55,6 @@ STATISTIC(NumSRA , "Number of aggregate globals broken into scalars"); STATISTIC(NumHeapSRA , "Number of heap objects SRA'd"); STATISTIC(NumSubstitute,"Number of globals with initializers stored into them"); STATISTIC(NumDeleted , "Number of globals deleted"); -STATISTIC(NumFnDeleted , "Number of functions deleted"); STATISTIC(NumGlobUses , "Number of global uses devirtualized"); STATISTIC(NumLocalized , "Number of globals localized"); STATISTIC(NumShrunkToBool , "Number of global vars shrunk to booleans"); @@ -69,6 +69,7 @@ namespace { struct GlobalOpt : public ModulePass { void getAnalysisUsage(AnalysisUsage &AU) const override { AU.addRequired<TargetLibraryInfoWrapperPass>(); + AU.addRequired<DominatorTreeWrapperPass>(); } static char ID; // Pass identification, replacement for typeid GlobalOpt() : ModulePass(ID) { @@ -81,11 +82,14 @@ namespace { bool OptimizeFunctions(Module &M); bool OptimizeGlobalVars(Module &M); bool OptimizeGlobalAliases(Module &M); - bool ProcessGlobal(GlobalVariable *GV,Module::global_iterator &GVI); - bool ProcessInternalGlobal(GlobalVariable *GV,Module::global_iterator &GVI, - const GlobalStatus &GS); + bool deleteIfDead(GlobalValue &GV); + bool processGlobal(GlobalValue &GV); + bool processInternalGlobal(GlobalVariable *GV, const GlobalStatus &GS); bool OptimizeEmptyGlobalCXXDtors(Function *CXAAtExitFn); + bool isPointerValueDeadOnEntryToFunction(const Function *F, + GlobalValue *GV); + TargetLibraryInfo *TLI; SmallSet<const Comdat *, 8> NotDiscardableComdats; }; @@ -95,13 +99,14 @@ char GlobalOpt::ID = 0; INITIALIZE_PASS_BEGIN(GlobalOpt, "globalopt", "Global Variable Optimizer", false, false) INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass) +INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) INITIALIZE_PASS_END(GlobalOpt, "globalopt", "Global Variable Optimizer", false, false) ModulePass *llvm::createGlobalOptimizerPass() { return new GlobalOpt(); } -/// isLeakCheckerRoot - Is this global variable possibly used by a leak checker -/// as a root? If so, we might not really want to eliminate the stores to it. +/// Is this global variable possibly used by a leak checker as a root? If so, +/// we might not really want to eliminate the stores to it. static bool isLeakCheckerRoot(GlobalVariable *GV) { // A global variable is a root if it is a pointer, or could plausibly contain // a pointer. There are two challenges; one is that we could have a struct @@ -176,10 +181,9 @@ static bool IsSafeComputationToRemove(Value *V, const TargetLibraryInfo *TLI) { } while (1); } -/// CleanupPointerRootUsers - This GV is a pointer root. Loop over all users -/// of the global and clean up any that obviously don't assign the global a -/// value that isn't dynamically allocated. -/// +/// This GV is a pointer root. Loop over all users of the global and clean up +/// any that obviously don't assign the global a value that isn't dynamically +/// allocated. static bool CleanupPointerRootUsers(GlobalVariable *GV, const TargetLibraryInfo *TLI) { // A brief explanation of leak checkers. The goal is to find bugs where @@ -263,10 +267,9 @@ static bool CleanupPointerRootUsers(GlobalVariable *GV, return Changed; } -/// CleanupConstantGlobalUsers - We just marked GV constant. Loop over all -/// users of the global, cleaning up the obvious ones. This is largely just a -/// quick scan over the use list to clean up the easy and obvious cruft. This -/// returns true if it made a change. +/// We just marked GV constant. Loop over all users of the global, cleaning up +/// the obvious ones. This is largely just a quick scan over the use list to +/// clean up the easy and obvious cruft. This returns true if it made a change. static bool CleanupConstantGlobalUsers(Value *V, Constant *Init, const DataLayout &DL, TargetLibraryInfo *TLI) { @@ -353,8 +356,8 @@ static bool CleanupConstantGlobalUsers(Value *V, Constant *Init, return Changed; } -/// isSafeSROAElementUse - Return true if the specified instruction is a safe -/// user of a derived expression from a global that we want to SROA. +/// Return true if the specified instruction is a safe user of a derived +/// expression from a global that we want to SROA. static bool isSafeSROAElementUse(Value *V) { // We might have a dead and dangling constant hanging off of here. if (Constant *C = dyn_cast<Constant>(V)) @@ -385,9 +388,8 @@ static bool isSafeSROAElementUse(Value *V) { } -/// IsUserOfGlobalSafeForSRA - U is a direct user of the specified global value. -/// Look at it and its uses and decide whether it is safe to SROA this global. -/// +/// U is a direct user of the specified global value. Look at it and its uses +/// and decide whether it is safe to SROA this global. static bool IsUserOfGlobalSafeForSRA(User *U, GlobalValue *GV) { // The user of the global must be a GEP Inst or a ConstantExpr GEP. if (!isa<GetElementPtrInst>(U) && @@ -452,9 +454,8 @@ static bool IsUserOfGlobalSafeForSRA(User *U, GlobalValue *GV) { return true; } -/// GlobalUsersSafeToSRA - Look at all uses of the global and decide whether it -/// is safe for us to perform this transformation. -/// +/// Look at all uses of the global and decide whether it is safe for us to +/// perform this transformation. static bool GlobalUsersSafeToSRA(GlobalValue *GV) { for (User *U : GV->users()) if (!IsUserOfGlobalSafeForSRA(U, GV)) @@ -464,10 +465,10 @@ static bool GlobalUsersSafeToSRA(GlobalValue *GV) { } -/// SRAGlobal - Perform scalar replacement of aggregates on the specified global -/// variable. This opens the door for other optimizations by exposing the -/// behavior of the program in a more fine-grained way. We have determined that -/// this transformation is safe already. We return the first global variable we +/// Perform scalar replacement of aggregates on the specified global variable. +/// This opens the door for other optimizations by exposing the behavior of the +/// program in a more fine-grained way. We have determined that this +/// transformation is safe already. We return the first global variable we /// insert so that the caller can reprocess it. static GlobalVariable *SRAGlobal(GlobalVariable *GV, const DataLayout &DL) { // Make sure this global only has simple uses that we can SRA. @@ -497,7 +498,8 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const DataLayout &DL) { In, GV->getName()+"."+Twine(i), GV->getThreadLocalMode(), GV->getType()->getAddressSpace()); - Globals.insert(GV, NGV); + NGV->setExternallyInitialized(GV->isExternallyInitialized()); + Globals.push_back(NGV); NewGlobals.push_back(NGV); // Calculate the known alignment of the field. If the original aggregate @@ -530,7 +532,8 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const DataLayout &DL) { In, GV->getName()+"."+Twine(i), GV->getThreadLocalMode(), GV->getType()->getAddressSpace()); - Globals.insert(GV, NGV); + NGV->setExternallyInitialized(GV->isExternallyInitialized()); + Globals.push_back(NGV); NewGlobals.push_back(NGV); // Calculate the known alignment of the field. If the original aggregate @@ -545,7 +548,7 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const DataLayout &DL) { if (NewGlobals.empty()) return nullptr; - DEBUG(dbgs() << "PERFORMING GLOBAL SRA ON: " << *GV); + DEBUG(dbgs() << "PERFORMING GLOBAL SRA ON: " << *GV << "\n"); Constant *NullInt =Constant::getNullValue(Type::getInt32Ty(GV->getContext())); @@ -610,9 +613,9 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const DataLayout &DL) { return FirstGlobal != NewGlobals.size() ? NewGlobals[FirstGlobal] : nullptr; } -/// AllUsesOfValueWillTrapIfNull - Return true if all users of the specified -/// value will trap if the value is dynamically null. PHIs keeps track of any -/// phi nodes we've seen to avoid reprocessing them. +/// Return true if all users of the specified value will trap if the value is +/// dynamically null. PHIs keeps track of any phi nodes we've seen to avoid +/// reprocessing them. static bool AllUsesOfValueWillTrapIfNull(const Value *V, SmallPtrSetImpl<const PHINode*> &PHIs) { for (const User *U : V->users()) @@ -653,9 +656,9 @@ static bool AllUsesOfValueWillTrapIfNull(const Value *V, return true; } -/// AllUsesOfLoadedValueWillTrapIfNull - Return true if all uses of any loads -/// from GV will trap if the loaded value is null. Note that this also permits -/// comparisons of the loaded value against null, as a special case. +/// Return true if all uses of any loads from GV will trap if the loaded value +/// is null. Note that this also permits comparisons of the loaded value +/// against null, as a special case. static bool AllUsesOfLoadedValueWillTrapIfNull(const GlobalVariable *GV) { for (const User *U : GV->users()) if (const LoadInst *LI = dyn_cast<LoadInst>(U)) { @@ -735,10 +738,10 @@ static bool OptimizeAwayTrappingUsesOfValue(Value *V, Constant *NewV) { } -/// OptimizeAwayTrappingUsesOfLoads - The specified global has only one non-null -/// value stored into it. If there are uses of the loaded value that would trap -/// if the loaded value is dynamically null, then we know that they cannot be -/// reachable with a null optimize away the load. +/// The specified global has only one non-null value stored into it. If there +/// are uses of the loaded value that would trap if the loaded value is +/// dynamically null, then we know that they cannot be reachable with a null +/// optimize away the load. static bool OptimizeAwayTrappingUsesOfLoads(GlobalVariable *GV, Constant *LV, const DataLayout &DL, TargetLibraryInfo *TLI) { @@ -778,7 +781,7 @@ static bool OptimizeAwayTrappingUsesOfLoads(GlobalVariable *GV, Constant *LV, } if (Changed) { - DEBUG(dbgs() << "OPTIMIZED LOADS FROM STORED ONCE POINTER: " << *GV); + DEBUG(dbgs() << "OPTIMIZED LOADS FROM STORED ONCE POINTER: " << *GV << "\n"); ++NumGlobUses; } @@ -801,8 +804,8 @@ static bool OptimizeAwayTrappingUsesOfLoads(GlobalVariable *GV, Constant *LV, return Changed; } -/// ConstantPropUsersOf - Walk the use list of V, constant folding all of the -/// instructions that are foldable. +/// Walk the use list of V, constant folding all of the instructions that are +/// foldable. static void ConstantPropUsersOf(Value *V, const DataLayout &DL, TargetLibraryInfo *TLI) { for (Value::user_iterator UI = V->user_begin(), E = V->user_end(); UI != E; ) @@ -818,11 +821,11 @@ static void ConstantPropUsersOf(Value *V, const DataLayout &DL, } } -/// OptimizeGlobalAddressOfMalloc - This function takes the specified global -/// variable, and transforms the program as if it always contained the result of -/// the specified malloc. Because it is always the result of the specified -/// malloc, there is no reason to actually DO the malloc. Instead, turn the -/// malloc into a global, and any loads of GV as uses of the new global. +/// This function takes the specified global variable, and transforms the +/// program as if it always contained the result of the specified malloc. +/// Because it is always the result of the specified malloc, there is no reason +/// to actually DO the malloc. Instead, turn the malloc into a global, and any +/// loads of GV as uses of the new global. static GlobalVariable * OptimizeGlobalAddressOfMalloc(GlobalVariable *GV, CallInst *CI, Type *AllocTy, ConstantInt *NElements, const DataLayout &DL, @@ -838,13 +841,10 @@ OptimizeGlobalAddressOfMalloc(GlobalVariable *GV, CallInst *CI, Type *AllocTy, // Create the new global variable. The contents of the malloc'd memory is // undefined, so initialize with an undef value. - GlobalVariable *NewGV = new GlobalVariable(*GV->getParent(), - GlobalType, false, - GlobalValue::InternalLinkage, - UndefValue::get(GlobalType), - GV->getName()+".body", - GV, - GV->getThreadLocalMode()); + GlobalVariable *NewGV = new GlobalVariable( + *GV->getParent(), GlobalType, false, GlobalValue::InternalLinkage, + UndefValue::get(GlobalType), GV->getName() + ".body", nullptr, + GV->getThreadLocalMode()); // If there are bitcast users of the malloc (which is typical, usually we have // a malloc + bitcast) then replace them with uses of the new global. Update @@ -935,7 +935,7 @@ OptimizeGlobalAddressOfMalloc(GlobalVariable *GV, CallInst *CI, Type *AllocTy, cast<StoreInst>(InitBool->user_back())->eraseFromParent(); delete InitBool; } else - GV->getParent()->getGlobalList().insert(GV, InitBool); + GV->getParent()->getGlobalList().insert(GV->getIterator(), InitBool); // Now the GV is dead, nuke it and the malloc.. GV->eraseFromParent(); @@ -951,10 +951,9 @@ OptimizeGlobalAddressOfMalloc(GlobalVariable *GV, CallInst *CI, Type *AllocTy, return NewGV; } -/// ValueIsOnlyUsedLocallyOrStoredToOneGlobal - Scan the use-list of V checking -/// to make sure that there are no complex uses of V. We permit simple things -/// like dereferencing the pointer, but not storing through the address, unless -/// it is to the specified global. +/// Scan the use-list of V checking to make sure that there are no complex uses +/// of V. We permit simple things like dereferencing the pointer, but not +/// storing through the address, unless it is to the specified global. static bool ValueIsOnlyUsedLocallyOrStoredToOneGlobal(const Instruction *V, const GlobalVariable *GV, SmallPtrSetImpl<const PHINode*> &PHIs) { @@ -998,10 +997,9 @@ static bool ValueIsOnlyUsedLocallyOrStoredToOneGlobal(const Instruction *V, return true; } -/// ReplaceUsesOfMallocWithGlobal - The Alloc pointer is stored into GV -/// somewhere. Transform all uses of the allocation into loads from the -/// global and uses of the resultant pointer. Further, delete the store into -/// GV. This assumes that these value pass the +/// The Alloc pointer is stored into GV somewhere. Transform all uses of the +/// allocation into loads from the global and uses of the resultant pointer. +/// Further, delete the store into GV. This assumes that these value pass the /// 'ValueIsOnlyUsedLocallyOrStoredToOneGlobal' predicate. static void ReplaceUsesOfMallocWithGlobal(Instruction *Alloc, GlobalVariable *GV) { @@ -1043,9 +1041,9 @@ static void ReplaceUsesOfMallocWithGlobal(Instruction *Alloc, } } -/// LoadUsesSimpleEnoughForHeapSRA - Verify that all uses of V (a load, or a phi -/// of a load) are simple enough to perform heap SRA on. This permits GEP's -/// that index through the array and struct field, icmps of null, and PHIs. +/// Verify that all uses of V (a load, or a phi of a load) are simple enough to +/// perform heap SRA on. This permits GEP's that index through the array and +/// struct field, icmps of null, and PHIs. static bool LoadUsesSimpleEnoughForHeapSRA(const Value *V, SmallPtrSetImpl<const PHINode*> &LoadUsingPHIs, SmallPtrSetImpl<const PHINode*> &LoadUsingPHIsPerLoad) { @@ -1096,8 +1094,8 @@ static bool LoadUsesSimpleEnoughForHeapSRA(const Value *V, } -/// AllGlobalLoadUsesSimpleEnoughForHeapSRA - If all users of values loaded from -/// GV are simple enough to perform HeapSRA, return true. +/// If all users of values loaded from GV are simple enough to perform HeapSRA, +/// return true. static bool AllGlobalLoadUsesSimpleEnoughForHeapSRA(const GlobalVariable *GV, Instruction *StoredVal) { SmallPtrSet<const PHINode*, 32> LoadUsingPHIs; @@ -1186,8 +1184,8 @@ static Value *GetHeapSROAValue(Value *V, unsigned FieldNo, return FieldVals[FieldNo] = Result; } -/// RewriteHeapSROALoadUser - Given a load instruction and a value derived from -/// the load, rewrite the derived value to use the HeapSRoA'd load. +/// Given a load instruction and a value derived from the load, rewrite the +/// derived value to use the HeapSRoA'd load. static void RewriteHeapSROALoadUser(Instruction *LoadUser, DenseMap<Value*, std::vector<Value*> > &InsertedScalarizedValues, std::vector<std::pair<PHINode*, unsigned> > &PHIsToRewrite) { @@ -1248,10 +1246,9 @@ static void RewriteHeapSROALoadUser(Instruction *LoadUser, } } -/// RewriteUsesOfLoadForHeapSRoA - We are performing Heap SRoA on a global. Ptr -/// is a value loaded from the global. Eliminate all uses of Ptr, making them -/// use FieldGlobals instead. All uses of loaded values satisfy -/// AllGlobalLoadUsesSimpleEnoughForHeapSRA. +/// We are performing Heap SRoA on a global. Ptr is a value loaded from the +/// global. Eliminate all uses of Ptr, making them use FieldGlobals instead. +/// All uses of loaded values satisfy AllGlobalLoadUsesSimpleEnoughForHeapSRA. static void RewriteUsesOfLoadForHeapSRoA(LoadInst *Load, DenseMap<Value*, std::vector<Value*> > &InsertedScalarizedValues, std::vector<std::pair<PHINode*, unsigned> > &PHIsToRewrite) { @@ -1266,8 +1263,8 @@ static void RewriteUsesOfLoadForHeapSRoA(LoadInst *Load, } } -/// PerformHeapAllocSRoA - CI is an allocation of an array of structures. Break -/// it up into multiple allocations of arrays of the fields. +/// CI is an allocation of an array of structures. Break it up into multiple +/// allocations of arrays of the fields. static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV, CallInst *CI, Value *NElems, const DataLayout &DL, const TargetLibraryInfo *TLI) { @@ -1291,12 +1288,10 @@ static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV, CallInst *CI, Type *FieldTy = STy->getElementType(FieldNo); PointerType *PFieldTy = PointerType::get(FieldTy, AS); - GlobalVariable *NGV = - new GlobalVariable(*GV->getParent(), - PFieldTy, false, GlobalValue::InternalLinkage, - Constant::getNullValue(PFieldTy), - GV->getName() + ".f" + Twine(FieldNo), GV, - GV->getThreadLocalMode()); + GlobalVariable *NGV = new GlobalVariable( + *GV->getParent(), PFieldTy, false, GlobalValue::InternalLinkage, + Constant::getNullValue(PFieldTy), GV->getName() + ".f" + Twine(FieldNo), + nullptr, GV->getThreadLocalMode()); FieldGlobals.push_back(NGV); unsigned TypeSize = DL.getTypeAllocSize(FieldTy); @@ -1336,7 +1331,8 @@ static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV, CallInst *CI, // Split the basic block at the old malloc. BasicBlock *OrigBB = CI->getParent(); - BasicBlock *ContBB = OrigBB->splitBasicBlock(CI, "malloc_cont"); + BasicBlock *ContBB = + OrigBB->splitBasicBlock(CI->getIterator(), "malloc_cont"); // Create the block to check the first condition. Put all these blocks at the // end of the function as they are unlikely to be executed. @@ -1376,9 +1372,8 @@ static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV, CallInst *CI, // CI is no longer needed, remove it. CI->eraseFromParent(); - /// InsertedScalarizedLoads - As we process loads, if we can't immediately - /// update all uses of the load, keep track of what scalarized loads are - /// inserted for a given load. + /// As we process loads, if we can't immediately update all uses of the load, + /// keep track of what scalarized loads are inserted for a given load. DenseMap<Value*, std::vector<Value*> > InsertedScalarizedValues; InsertedScalarizedValues[GV] = FieldGlobals; @@ -1454,13 +1449,11 @@ static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV, CallInst *CI, return cast<GlobalVariable>(FieldGlobals[0]); } -/// TryToOptimizeStoreOfMallocToGlobal - This function is called when we see a -/// pointer global variable with a single value stored it that is a malloc or -/// cast of malloc. -static bool TryToOptimizeStoreOfMallocToGlobal(GlobalVariable *GV, CallInst *CI, +/// This function is called when we see a pointer global variable with a single +/// value stored it that is a malloc or cast of malloc. +static bool tryToOptimizeStoreOfMallocToGlobal(GlobalVariable *GV, CallInst *CI, Type *AllocTy, AtomicOrdering Ordering, - Module::global_iterator &GVI, const DataLayout &DL, TargetLibraryInfo *TLI) { // If this is a malloc of an abstract type, don't touch it. @@ -1499,7 +1492,7 @@ static bool TryToOptimizeStoreOfMallocToGlobal(GlobalVariable *GV, CallInst *CI, // (2048 bytes currently), as we don't want to introduce a 16M global or // something. if (NElements->getZExtValue() * DL.getTypeAllocSize(AllocTy) < 2048) { - GVI = OptimizeGlobalAddressOfMalloc(GV, CI, AllocTy, NElements, DL, TLI); + OptimizeGlobalAddressOfMalloc(GV, CI, AllocTy, NElements, DL, TLI); return true; } @@ -1544,19 +1537,18 @@ static bool TryToOptimizeStoreOfMallocToGlobal(GlobalVariable *GV, CallInst *CI, CI = cast<CallInst>(Malloc); } - GVI = PerformHeapAllocSRoA(GV, CI, getMallocArraySize(CI, DL, TLI, true), - DL, TLI); + PerformHeapAllocSRoA(GV, CI, getMallocArraySize(CI, DL, TLI, true), DL, + TLI); return true; } return false; } -// OptimizeOnceStoredGlobal - Try to optimize globals based on the knowledge -// that only one value (besides its initializer) is ever stored to the global. -static bool OptimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal, +// Try to optimize globals based on the knowledge that only one value (besides +// its initializer) is ever stored to the global. +static bool optimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal, AtomicOrdering Ordering, - Module::global_iterator &GVI, const DataLayout &DL, TargetLibraryInfo *TLI) { // Ignore no-op GEPs and bitcasts. @@ -1577,9 +1569,8 @@ static bool OptimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal, return true; } else if (CallInst *CI = extractMallocCall(StoredOnceVal, TLI)) { Type *MallocType = getMallocAllocatedType(CI, TLI); - if (MallocType && - TryToOptimizeStoreOfMallocToGlobal(GV, CI, MallocType, Ordering, GVI, - DL, TLI)) + if (MallocType && tryToOptimizeStoreOfMallocToGlobal(GV, CI, MallocType, + Ordering, DL, TLI)) return true; } } @@ -1587,10 +1578,10 @@ static bool OptimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal, return false; } -/// TryToShrinkGlobalToBoolean - At this point, we have learned that the only -/// two values ever stored into GV are its initializer and OtherVal. See if we -/// can shrink the global into a boolean and select between the two values -/// whenever it is used. This exposes the values to other scalar optimizations. +/// At this point, we have learned that the only two values ever stored into GV +/// are its initializer and OtherVal. See if we can shrink the global into a +/// boolean and select between the two values whenever it is used. This exposes +/// the values to other scalar optimizations. static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { Type *GVElType = GV->getType()->getElementType(); @@ -1610,7 +1601,7 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { if (!isa<LoadInst>(U) && !isa<StoreInst>(U)) return false; - DEBUG(dbgs() << " *** SHRINKING TO BOOL: " << *GV); + DEBUG(dbgs() << " *** SHRINKING TO BOOL: " << *GV << "\n"); // Create the new global, initializing it to false. GlobalVariable *NewGV = new GlobalVariable(Type::getInt1Ty(GV->getContext()), @@ -1620,7 +1611,7 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { GV->getName()+".b", GV->getThreadLocalMode(), GV->getType()->getAddressSpace()); - GV->getParent()->getGlobalList().insert(GV, NewGV); + GV->getParent()->getGlobalList().insert(GV->getIterator(), NewGV); Constant *InitVal = GV->getInitializer(); assert(InitVal->getType() != Type::getInt1Ty(GV->getContext()) && @@ -1688,61 +1679,213 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { return true; } +bool GlobalOpt::deleteIfDead(GlobalValue &GV) { + GV.removeDeadConstantUsers(); -/// ProcessGlobal - Analyze the specified global variable and optimize it if -/// possible. If we make a change, return true. -bool GlobalOpt::ProcessGlobal(GlobalVariable *GV, - Module::global_iterator &GVI) { - // Do more involved optimizations if the global is internal. - GV->removeDeadConstantUsers(); + if (!GV.isDiscardableIfUnused()) + return false; - if (GV->use_empty()) { - DEBUG(dbgs() << "GLOBAL DEAD: " << *GV); - GV->eraseFromParent(); - ++NumDeleted; - return true; - } + if (const Comdat *C = GV.getComdat()) + if (!GV.hasLocalLinkage() && NotDiscardableComdats.count(C)) + return false; - if (!GV->hasLocalLinkage()) + bool Dead; + if (auto *F = dyn_cast<Function>(&GV)) + Dead = F->isDefTriviallyDead(); + else + Dead = GV.use_empty(); + if (!Dead) + return false; + + DEBUG(dbgs() << "GLOBAL DEAD: " << GV << "\n"); + GV.eraseFromParent(); + ++NumDeleted; + return true; +} + +/// Analyze the specified global variable and optimize it if possible. If we +/// make a change, return true. +bool GlobalOpt::processGlobal(GlobalValue &GV) { + // Do more involved optimizations if the global is internal. + if (!GV.hasLocalLinkage()) return false; GlobalStatus GS; - if (GlobalStatus::analyzeGlobal(GV, GS)) + if (GlobalStatus::analyzeGlobal(&GV, GS)) return false; - if (!GS.IsCompared && !GV->hasUnnamedAddr()) { - GV->setUnnamedAddr(true); + bool Changed = false; + if (!GS.IsCompared && !GV.hasUnnamedAddr()) { + GV.setUnnamedAddr(true); NumUnnamed++; + Changed = true; } - if (GV->isConstant() || !GV->hasInitializer()) + auto *GVar = dyn_cast<GlobalVariable>(&GV); + if (!GVar) + return Changed; + + if (GVar->isConstant() || !GVar->hasInitializer()) + return Changed; + + return processInternalGlobal(GVar, GS) || Changed; +} + +bool GlobalOpt::isPointerValueDeadOnEntryToFunction(const Function *F, GlobalValue *GV) { + // Find all uses of GV. We expect them all to be in F, and if we can't + // identify any of the uses we bail out. + // + // On each of these uses, identify if the memory that GV points to is + // used/required/live at the start of the function. If it is not, for example + // if the first thing the function does is store to the GV, the GV can + // possibly be demoted. + // + // We don't do an exhaustive search for memory operations - simply look + // through bitcasts as they're quite common and benign. + const DataLayout &DL = GV->getParent()->getDataLayout(); + SmallVector<LoadInst *, 4> Loads; + SmallVector<StoreInst *, 4> Stores; + for (auto *U : GV->users()) { + if (Operator::getOpcode(U) == Instruction::BitCast) { + for (auto *UU : U->users()) { + if (auto *LI = dyn_cast<LoadInst>(UU)) + Loads.push_back(LI); + else if (auto *SI = dyn_cast<StoreInst>(UU)) + Stores.push_back(SI); + else + return false; + } + continue; + } + + Instruction *I = dyn_cast<Instruction>(U); + if (!I) + return false; + assert(I->getParent()->getParent() == F); + + if (auto *LI = dyn_cast<LoadInst>(I)) + Loads.push_back(LI); + else if (auto *SI = dyn_cast<StoreInst>(I)) + Stores.push_back(SI); + else + return false; + } + + // We have identified all uses of GV into loads and stores. Now check if all + // of them are known not to depend on the value of the global at the function + // entry point. We do this by ensuring that every load is dominated by at + // least one store. + auto &DT = getAnalysis<DominatorTreeWrapperPass>(*const_cast<Function *>(F)) + .getDomTree(); + + // The below check is quadratic. Check we're not going to do too many tests. + // FIXME: Even though this will always have worst-case quadratic time, we + // could put effort into minimizing the average time by putting stores that + // have been shown to dominate at least one load at the beginning of the + // Stores array, making subsequent dominance checks more likely to succeed + // early. + // + // The threshold here is fairly large because global->local demotion is a + // very powerful optimization should it fire. + const unsigned Threshold = 100; + if (Loads.size() * Stores.size() > Threshold) return false; - return ProcessInternalGlobal(GV, GVI, GS); + for (auto *L : Loads) { + auto *LTy = L->getType(); + if (!std::any_of(Stores.begin(), Stores.end(), [&](StoreInst *S) { + auto *STy = S->getValueOperand()->getType(); + // The load is only dominated by the store if DomTree says so + // and the number of bits loaded in L is less than or equal to + // the number of bits stored in S. + return DT.dominates(S, L) && + DL.getTypeStoreSize(LTy) <= DL.getTypeStoreSize(STy); + })) + return false; + } + // All loads have known dependences inside F, so the global can be localized. + return true; +} + +/// C may have non-instruction users. Can all of those users be turned into +/// instructions? +static bool allNonInstructionUsersCanBeMadeInstructions(Constant *C) { + // We don't do this exhaustively. The most common pattern that we really need + // to care about is a constant GEP or constant bitcast - so just looking + // through one single ConstantExpr. + // + // The set of constants that this function returns true for must be able to be + // handled by makeAllConstantUsesInstructions. + for (auto *U : C->users()) { + if (isa<Instruction>(U)) + continue; + if (!isa<ConstantExpr>(U)) + // Non instruction, non-constantexpr user; cannot convert this. + return false; + for (auto *UU : U->users()) + if (!isa<Instruction>(UU)) + // A constantexpr used by another constant. We don't try and recurse any + // further but just bail out at this point. + return false; + } + + return true; +} + +/// C may have non-instruction users, and +/// allNonInstructionUsersCanBeMadeInstructions has returned true. Convert the +/// non-instruction users to instructions. +static void makeAllConstantUsesInstructions(Constant *C) { + SmallVector<ConstantExpr*,4> Users; + for (auto *U : C->users()) { + if (isa<ConstantExpr>(U)) + Users.push_back(cast<ConstantExpr>(U)); + else + // We should never get here; allNonInstructionUsersCanBeMadeInstructions + // should not have returned true for C. + assert( + isa<Instruction>(U) && + "Can't transform non-constantexpr non-instruction to instruction!"); + } + + SmallVector<Value*,4> UUsers; + for (auto *U : Users) { + UUsers.clear(); + for (auto *UU : U->users()) + UUsers.push_back(UU); + for (auto *UU : UUsers) { + Instruction *UI = cast<Instruction>(UU); + Instruction *NewU = U->getAsInstruction(); + NewU->insertBefore(UI); + UI->replaceUsesOfWith(U, NewU); + } + U->dropAllReferences(); + } } -/// ProcessInternalGlobal - Analyze the specified global variable and optimize +/// Analyze the specified global variable and optimize /// it if possible. If we make a change, return true. -bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, - Module::global_iterator &GVI, +bool GlobalOpt::processInternalGlobal(GlobalVariable *GV, const GlobalStatus &GS) { auto &DL = GV->getParent()->getDataLayout(); - // If this is a first class global and has only one accessing function - // and this function is main (which we know is not recursive), we replace - // the global with a local alloca in this function. + // If this is a first class global and has only one accessing function and + // this function is non-recursive, we replace the global with a local alloca + // in this function. // // NOTE: It doesn't make sense to promote non-single-value types since we // are just replacing static memory to stack memory. // // If the global is in different address space, don't bring it to stack. if (!GS.HasMultipleAccessingFunctions && - GS.AccessingFunction && !GS.HasNonInstructionUser && + GS.AccessingFunction && GV->getType()->getElementType()->isSingleValueType() && - GS.AccessingFunction->getName() == "main" && - GS.AccessingFunction->hasExternalLinkage() && - GV->getType()->getAddressSpace() == 0) { - DEBUG(dbgs() << "LOCALIZING GLOBAL: " << *GV); + GV->getType()->getAddressSpace() == 0 && + !GV->isExternallyInitialized() && + allNonInstructionUsersCanBeMadeInstructions(GV) && + GS.AccessingFunction->doesNotRecurse() && + isPointerValueDeadOnEntryToFunction(GS.AccessingFunction, GV) ) { + DEBUG(dbgs() << "LOCALIZING GLOBAL: " << *GV << "\n"); Instruction &FirstI = const_cast<Instruction&>(*GS.AccessingFunction ->getEntryBlock().begin()); Type *ElemTy = GV->getType()->getElementType(); @@ -1752,6 +1895,8 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, if (!isa<UndefValue>(GV->getInitializer())) new StoreInst(GV->getInitializer(), Alloca, &FirstI); + makeAllConstantUsesInstructions(GV); + GV->replaceAllUsesWith(Alloca); GV->eraseFromParent(); ++NumLocalized; @@ -1761,7 +1906,7 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, // If the global is never loaded (but may be stored to), it is dead. // Delete it now. if (!GS.IsLoaded) { - DEBUG(dbgs() << "GLOBAL NEVER LOADED: " << *GV); + DEBUG(dbgs() << "GLOBAL NEVER LOADED: " << *GV << "\n"); bool Changed; if (isLeakCheckerRoot(GV)) { @@ -1800,11 +1945,9 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, return true; } else if (!GV->getInitializer()->getType()->isSingleValueType()) { const DataLayout &DL = GV->getParent()->getDataLayout(); - if (GlobalVariable *FirstNewGV = SRAGlobal(GV, DL)) { - GVI = FirstNewGV; // Don't skip the newly produced globals! + if (SRAGlobal(GV, DL)) return true; - } - } else if (GS.StoredType == GlobalStatus::StoredOnce) { + } else if (GS.StoredType == GlobalStatus::StoredOnce && GS.StoredOnceValue) { // If the initial value for the global was an undef value, and if only // one other value was stored into it, we can just change the // initializer to be the stored value, then delete all stores to the @@ -1822,8 +1965,6 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, << "simplify all users and delete global!\n"); GV->eraseFromParent(); ++NumDeleted; - } else { - GVI = GV; } ++NumSubstitute; return true; @@ -1831,8 +1972,7 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, // Try to optimize globals based on the knowledge that only one value // (besides its initializer) is ever stored to the global. - if (OptimizeOnceStoredGlobal(GV, GS.StoredOnceValue, GS.Ordering, GVI, - DL, TLI)) + if (optimizeOnceStoredGlobal(GV, GS.StoredOnceValue, GS.Ordering, DL, TLI)) return true; // Otherwise, if the global was not a boolean, we can shrink it to be a @@ -1850,8 +1990,8 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, return false; } -/// ChangeCalleesToFastCall - Walk all of the direct calls of the specified -/// function, changing them to FastCC. +/// Walk all of the direct calls of the specified function, changing them to +/// FastCC. static void ChangeCalleesToFastCall(Function *F) { for (User *U : F->users()) { if (isa<BlockAddress>(U)) @@ -1898,38 +2038,38 @@ bool GlobalOpt::OptimizeFunctions(Module &M) { bool Changed = false; // Optimize functions. for (Module::iterator FI = M.begin(), E = M.end(); FI != E; ) { - Function *F = FI++; + Function *F = &*FI++; // Functions without names cannot be referenced outside this module. if (!F->hasName() && !F->isDeclaration() && !F->hasLocalLinkage()) F->setLinkage(GlobalValue::InternalLinkage); - const Comdat *C = F->getComdat(); - bool inComdat = C && NotDiscardableComdats.count(C); - F->removeDeadConstantUsers(); - if ((!inComdat || F->hasLocalLinkage()) && F->isDefTriviallyDead()) { - F->eraseFromParent(); + if (deleteIfDead(*F)) { Changed = true; - ++NumFnDeleted; - } else if (F->hasLocalLinkage()) { - if (isProfitableToMakeFastCC(F) && !F->isVarArg() && - !F->hasAddressTaken()) { - // If this function has a calling convention worth changing, is not a - // varargs function, and is only called directly, promote it to use the - // Fast calling convention. - F->setCallingConv(CallingConv::Fast); - ChangeCalleesToFastCall(F); - ++NumFastCallFns; - Changed = true; - } + continue; + } - if (F->getAttributes().hasAttrSomewhere(Attribute::Nest) && - !F->hasAddressTaken()) { - // The function is not used by a trampoline intrinsic, so it is safe - // to remove the 'nest' attribute. - RemoveNestAttribute(F); - ++NumNestRemoved; - Changed = true; - } + Changed |= processGlobal(*F); + + if (!F->hasLocalLinkage()) + continue; + if (isProfitableToMakeFastCC(F) && !F->isVarArg() && + !F->hasAddressTaken()) { + // If this function has a calling convention worth changing, is not a + // varargs function, and is only called directly, promote it to use the + // Fast calling convention. + F->setCallingConv(CallingConv::Fast); + ChangeCalleesToFastCall(F); + ++NumFastCallFns; + Changed = true; + } + + if (F->getAttributes().hasAttrSomewhere(Attribute::Nest) && + !F->hasAddressTaken()) { + // The function is not used by a trampoline intrinsic, so it is safe + // to remove the 'nest' attribute. + RemoveNestAttribute(F); + ++NumNestRemoved; + Changed = true; } } return Changed; @@ -1940,7 +2080,7 @@ bool GlobalOpt::OptimizeGlobalVars(Module &M) { for (Module::global_iterator GVI = M.global_begin(), E = M.global_end(); GVI != E; ) { - GlobalVariable *GV = GVI++; + GlobalVariable *GV = &*GVI++; // Global variables without names cannot be referenced outside this module. if (!GV->hasName() && !GV->isDeclaration() && !GV->hasLocalLinkage()) GV->setLinkage(GlobalValue::InternalLinkage); @@ -1953,12 +2093,12 @@ bool GlobalOpt::OptimizeGlobalVars(Module &M) { GV->setInitializer(New); } - if (GV->isDiscardableIfUnused()) { - if (const Comdat *C = GV->getComdat()) - if (NotDiscardableComdats.count(C) && !GV->hasLocalLinkage()) - continue; - Changed |= ProcessGlobal(GV, GVI); + if (deleteIfDead(*GV)) { + Changed = true; + continue; } + + Changed |= processGlobal(*GV); } return Changed; } @@ -1968,8 +2108,8 @@ isSimpleEnoughValueToCommit(Constant *C, SmallPtrSetImpl<Constant *> &SimpleConstants, const DataLayout &DL); -/// isSimpleEnoughValueToCommit - Return true if the specified constant can be -/// handled by the code generator. We don't want to generate something like: +/// Return true if the specified constant can be handled by the code generator. +/// We don't want to generate something like: /// void *X = &X/42; /// because the code generator doesn't have a relocation that can handle that. /// @@ -2044,11 +2184,11 @@ isSimpleEnoughValueToCommit(Constant *C, } -/// isSimpleEnoughPointerToCommit - Return true if this constant is simple -/// enough for us to understand. In particular, if it is a cast to anything -/// other than from one pointer type to another pointer type, we punt. -/// We basically just support direct accesses to globals and GEP's of -/// globals. This should be kept up to date with CommitValueTo. +/// Return true if this constant is simple enough for us to understand. In +/// particular, if it is a cast to anything other than from one pointer type to +/// another pointer type, we punt. We basically just support direct accesses to +/// globals and GEP's of globals. This should be kept up to date with +/// CommitValueTo. static bool isSimpleEnoughPointerToCommit(Constant *C) { // Conservatively, avoid aggregate types. This is because we don't // want to worry about them partially overlapping other stores. @@ -2095,9 +2235,9 @@ static bool isSimpleEnoughPointerToCommit(Constant *C) { return false; } -/// EvaluateStoreInto - Evaluate a piece of a constantexpr store into a global -/// initializer. This returns 'Init' modified to reflect 'Val' stored into it. -/// At this point, the GEP operands of Addr [0, OpNo) have been stepped into. +/// Evaluate a piece of a constantexpr store into a global initializer. This +/// returns 'Init' modified to reflect 'Val' stored into it. At this point, the +/// GEP operands of Addr [0, OpNo) have been stepped into. static Constant *EvaluateStoreInto(Constant *Init, Constant *Val, ConstantExpr *Addr, unsigned OpNo) { // Base case of the recursion. @@ -2144,7 +2284,7 @@ static Constant *EvaluateStoreInto(Constant *Init, Constant *Val, return ConstantVector::get(Elts); } -/// CommitValueTo - We have decided that Addr (which satisfies the predicate +/// We have decided that Addr (which satisfies the predicate /// isSimpleEnoughPointerToCommit) should get Val as its value. Make it happen. static void CommitValueTo(Constant *Val, Constant *Addr) { if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) { @@ -2160,10 +2300,10 @@ static void CommitValueTo(Constant *Val, Constant *Addr) { namespace { -/// Evaluator - This class evaluates LLVM IR, producing the Constant -/// representing each SSA instruction. Changes to global variables are stored -/// in a mapping that can be iterated over after the evaluation is complete. -/// Once an evaluation call fails, the evaluation object should not be reused. +/// This class evaluates LLVM IR, producing the Constant representing each SSA +/// instruction. Changes to global variables are stored in a mapping that can +/// be iterated over after the evaluation is complete. Once an evaluation call +/// fails, the evaluation object should not be reused. class Evaluator { public: Evaluator(const DataLayout &DL, const TargetLibraryInfo *TLI) @@ -2180,15 +2320,15 @@ public: Tmp->replaceAllUsesWith(Constant::getNullValue(Tmp->getType())); } - /// EvaluateFunction - Evaluate a call to function F, returning true if - /// successful, false if we can't evaluate it. ActualArgs contains the formal - /// arguments for the function. + /// Evaluate a call to function F, returning true if successful, false if we + /// can't evaluate it. ActualArgs contains the formal arguments for the + /// function. bool EvaluateFunction(Function *F, Constant *&RetVal, const SmallVectorImpl<Constant*> &ActualArgs); - /// EvaluateBlock - Evaluate all instructions in block BB, returning true if - /// successful, false if we can't evaluate it. NewBB returns the next BB that - /// control flows into, or null upon return. + /// Evaluate all instructions in block BB, returning true if successful, false + /// if we can't evaluate it. NewBB returns the next BB that control flows + /// into, or null upon return. bool EvaluateBlock(BasicBlock::iterator CurInst, BasicBlock *&NextBB); Constant *getVal(Value *V) { @@ -2213,32 +2353,31 @@ public: private: Constant *ComputeLoadResult(Constant *P); - /// ValueStack - As we compute SSA register values, we store their contents - /// here. The back of the deque contains the current function and the stack - /// contains the values in the calling frames. + /// As we compute SSA register values, we store their contents here. The back + /// of the deque contains the current function and the stack contains the + /// values in the calling frames. std::deque<DenseMap<Value*, Constant*>> ValueStack; - /// CallStack - This is used to detect recursion. In pathological situations - /// we could hit exponential behavior, but at least there is nothing - /// unbounded. + /// This is used to detect recursion. In pathological situations we could hit + /// exponential behavior, but at least there is nothing unbounded. SmallVector<Function*, 4> CallStack; - /// MutatedMemory - For each store we execute, we update this map. Loads - /// check this to get the most up-to-date value. If evaluation is successful, - /// this state is committed to the process. + /// For each store we execute, we update this map. Loads check this to get + /// the most up-to-date value. If evaluation is successful, this state is + /// committed to the process. DenseMap<Constant*, Constant*> MutatedMemory; - /// AllocaTmps - To 'execute' an alloca, we create a temporary global variable - /// to represent its body. This vector is needed so we can delete the - /// temporary globals when we are done. + /// To 'execute' an alloca, we create a temporary global variable to represent + /// its body. This vector is needed so we can delete the temporary globals + /// when we are done. SmallVector<std::unique_ptr<GlobalVariable>, 32> AllocaTmps; - /// Invariants - These global variables have been marked invariant by the - /// static constructor. + /// These global variables have been marked invariant by the static + /// constructor. SmallPtrSet<GlobalVariable*, 8> Invariants; - /// SimpleConstants - These are constants we have checked and know to be - /// simple enough to live in a static initializer of a global. + /// These are constants we have checked and know to be simple enough to live + /// in a static initializer of a global. SmallPtrSet<Constant*, 8> SimpleConstants; const DataLayout &DL; @@ -2247,9 +2386,8 @@ private: } // anonymous namespace -/// ComputeLoadResult - Return the value that would be computed by a load from -/// P after the stores reflected by 'memory' have been performed. If we can't -/// decide, return null. +/// Return the value that would be computed by a load from P after the stores +/// reflected by 'memory' have been performed. If we can't decide, return null. Constant *Evaluator::ComputeLoadResult(Constant *P) { // If this memory location has been recently stored, use the stored value: it // is the most up-to-date. @@ -2275,9 +2413,9 @@ Constant *Evaluator::ComputeLoadResult(Constant *P) { return nullptr; // don't know how to evaluate. } -/// EvaluateBlock - Evaluate all instructions in block BB, returning true if -/// successful, false if we can't evaluate it. NewBB returns the next BB that -/// control flows into, or null upon return. +/// Evaluate all instructions in block BB, returning true if successful, false +/// if we can't evaluate it. NewBB returns the next BB that control flows into, +/// or null upon return. bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst, BasicBlock *&NextBB) { // This is the main evaluation loop. @@ -2438,7 +2576,7 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst, InstResult = AllocaTmps.back().get(); DEBUG(dbgs() << "Found an alloca. Result: " << *InstResult << "\n"); } else if (isa<CallInst>(CurInst) || isa<InvokeInst>(CurInst)) { - CallSite CS(CurInst); + CallSite CS(&*CurInst); // Debug info can safely be ignored here. if (isa<DbgInfoIntrinsic>(CS.getInstruction())) { @@ -2504,6 +2642,10 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst, // Continue even if we do nothing. ++CurInst; continue; + } else if (II->getIntrinsicID() == Intrinsic::assume) { + DEBUG(dbgs() << "Skipping assume intrinsic.\n"); + ++CurInst; + continue; } DEBUG(dbgs() << "Unknown intrinsic. Can not evaluate.\n"); @@ -2600,7 +2742,7 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst, if (ConstantExpr *CE = dyn_cast<ConstantExpr>(InstResult)) InstResult = ConstantFoldConstantExpression(CE, DL, TLI); - setVal(CurInst, InstResult); + setVal(&*CurInst, InstResult); } // If we just processed an invoke, we finished evaluating the block. @@ -2615,9 +2757,9 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst, } } -/// EvaluateFunction - Evaluate a call to function F, returning true if -/// successful, false if we can't evaluate it. ActualArgs contains the formal -/// arguments for the function. +/// Evaluate a call to function F, returning true if successful, false if we +/// can't evaluate it. ActualArgs contains the formal arguments for the +/// function. bool Evaluator::EvaluateFunction(Function *F, Constant *&RetVal, const SmallVectorImpl<Constant*> &ActualArgs) { // Check to see if this function is already executing (recursion). If so, @@ -2631,7 +2773,7 @@ bool Evaluator::EvaluateFunction(Function *F, Constant *&RetVal, unsigned ArgNo = 0; for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end(); AI != E; ++AI, ++ArgNo) - setVal(AI, ActualArgs[ArgNo]); + setVal(&*AI, ActualArgs[ArgNo]); // ExecutedBlocks - We only handle non-looping, non-recursive code. As such, // we can only evaluate any one basic block at most once. This set keeps @@ -2639,7 +2781,7 @@ bool Evaluator::EvaluateFunction(Function *F, Constant *&RetVal, SmallPtrSet<BasicBlock*, 32> ExecutedBlocks; // CurBB - The current basic block we're evaluating. - BasicBlock *CurBB = F->begin(); + BasicBlock *CurBB = &F->front(); BasicBlock::iterator CurInst = CurBB->begin(); @@ -2679,8 +2821,8 @@ bool Evaluator::EvaluateFunction(Function *F, Constant *&RetVal, } } -/// EvaluateStaticConstructor - Evaluate static constructors in the function, if -/// we can. Return true if we can, false otherwise. +/// Evaluate static constructors in the function, if we can. Return true if we +/// can, false otherwise. static bool EvaluateStaticConstructor(Function *F, const DataLayout &DL, const TargetLibraryInfo *TLI) { // Call the function. @@ -2708,7 +2850,8 @@ static bool EvaluateStaticConstructor(Function *F, const DataLayout &DL, } static int compareNames(Constant *const *A, Constant *const *B) { - return (*A)->getName().compare((*B)->getName()); + return (*A)->stripPointerCasts()->getName().compare( + (*B)->stripPointerCasts()->getName()); } static void setUsedInitializer(GlobalVariable &V, @@ -2742,7 +2885,7 @@ static void setUsedInitializer(GlobalVariable &V, } namespace { -/// \brief An easy to access representation of llvm.used and llvm.compiler.used. +/// An easy to access representation of llvm.used and llvm.compiler.used. class LLVMUsed { SmallPtrSet<GlobalValue *, 8> Used; SmallPtrSet<GlobalValue *, 8> CompilerUsed; @@ -2861,10 +3004,17 @@ bool GlobalOpt::OptimizeGlobalAliases(Module &M) { for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end(); I != E;) { - Module::alias_iterator J = I++; + GlobalAlias *J = &*I++; + // Aliases without names cannot be referenced outside this module. if (!J->hasName() && !J->isDeclaration() && !J->hasLocalLinkage()) J->setLinkage(GlobalValue::InternalLinkage); + + if (deleteIfDead(*J)) { + Changed = true; + continue; + } + // If the aliasee may change at link time, nothing can be done - bail out. if (J->mayBeOverridden()) continue; @@ -2889,15 +3039,15 @@ bool GlobalOpt::OptimizeGlobalAliases(Module &M) { if (RenameTarget) { // Give the aliasee the name, linkage and other attributes of the alias. - Target->takeName(J); + Target->takeName(&*J); Target->setLinkage(J->getLinkage()); Target->setVisibility(J->getVisibility()); Target->setDLLStorageClass(J->getDLLStorageClass()); - if (Used.usedErase(J)) + if (Used.usedErase(&*J)) Used.usedInsert(Target); - if (Used.compilerUsedErase(J)) + if (Used.compilerUsedErase(&*J)) Used.compilerUsedInsert(Target); } else if (mayHaveOtherReferences(*J, Used)) continue; @@ -2936,8 +3086,8 @@ static Function *FindCXAAtExit(Module &M, TargetLibraryInfo *TLI) { return Fn; } -/// cxxDtorIsEmpty - Returns whether the given function is an empty C++ -/// destructor and can therefore be eliminated. +/// Returns whether the given function is an empty C++ destructor and can +/// therefore be eliminated. /// Note that we assume that other optimization passes have already simplified /// the code so we only look for a function with a single basic block, where /// the only allowed instructions are 'ret', 'call' to an empty C++ dtor and @@ -3081,3 +3231,4 @@ bool GlobalOpt::runOnModule(Module &M) { return Changed; } + |
