#include "LLVMContextImpl.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallString.h"
+#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instructions.h"
-#include "llvm/IR/LeakDetector.h"
+#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
+#include "llvm/IR/Statepoint.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/IR/ValueSymbolTable.h"
#include "llvm/Support/Debug.h"
static inline Type *checkType(Type *Ty) {
assert(Ty && "Value defined with a null type: Error!");
- return const_cast<Type*>(Ty);
+ return Ty;
}
Value::Value(Type *ty, unsigned scid)
- : SubclassID(scid), HasValueHandle(0),
- SubclassOptionalData(0), SubclassData(0), VTy((Type*)checkType(ty)),
- UseList(nullptr), Name(nullptr) {
+ : VTy(checkType(ty)), UseList(nullptr), SubclassID(scid), HasValueHandle(0),
+ SubclassOptionalData(0), SubclassData(0), NumOperands(0) {
// FIXME: Why isn't this in the subclass gunk??
// Note, we cannot call isa<CallInst> before the CallInst has been
// constructed.
// Notify all ValueHandles (if present) that this value is going away.
if (HasValueHandle)
ValueHandleBase::ValueIsDeleted(this);
+ if (isUsedByMetadata())
+ ValueAsMetadata::handleDeletion(this);
#ifndef NDEBUG // Only in -g mode...
// Check to make sure that there are no uses of this value that are still
// If this value is named, destroy the name. This should not be in a symtab
// at this point.
- if (Name && SubclassID != MDStringVal)
- Name->Destroy();
+ destroyValueName();
+}
- // There should be no uses of this object anymore, remove it.
- LeakDetector::removeGarbageObject(this);
+void Value::destroyValueName() {
+ ValueName *Name = getValueName();
+ if (Name)
+ Name->Destroy();
+ setValueName(nullptr);
}
-/// hasNUses - Return true if this Value has exactly N users.
-///
bool Value::hasNUses(unsigned N) const {
const_use_iterator UI = use_begin(), E = use_end();
return UI == E;
}
-/// hasNUsesOrMore - Return true if this value has N users or more. This is
-/// logically equivalent to getNumUses() >= N.
-///
bool Value::hasNUsesOrMore(unsigned N) const {
const_use_iterator UI = use_begin(), E = use_end();
return true;
}
-/// isUsedInBasicBlock - Return true if this value is used in the specified
-/// basic block.
bool Value::isUsedInBasicBlock(const BasicBlock *BB) const {
// This can be computed either by scanning the instructions in BB, or by
// scanning the use list of this Value. Both lists can be very long, but
return false;
}
-
-/// getNumUses - This method computes the number of uses of this Value. This
-/// is a linear time operation. Use hasOneUse or hasNUses to check for specific
-/// values.
unsigned Value::getNumUses() const {
return (unsigned)std::distance(use_begin(), use_end());
}
} else if (Argument *A = dyn_cast<Argument>(V)) {
if (Function *P = A->getParent())
ST = &P->getValueSymbolTable();
- } else if (isa<MDString>(V))
- return true;
- else {
+ } else {
assert(isa<Constant>(V) && "Unknown value type!");
return true; // no name is setable for this.
}
// Make sure the empty string is still a C string. For historical reasons,
// some clients want to call .data() on the result and expect it to be null
// terminated.
- if (!Name) return StringRef("", 0);
- return Name->getKey();
+ if (!getValueName())
+ return StringRef("", 0);
+ return getValueName()->getKey();
}
void Value::setName(const Twine &NewName) {
- assert(SubclassID != MDStringVal &&
- "Cannot set the name of MDString with this method!");
-
// Fast path for common IRBuilder case of setName("") when there is no name.
if (NewName.isTriviallyEmpty() && !hasName())
return;
if (!ST) { // No symbol table to update? Just do the change.
if (NameRef.empty()) {
// Free the name for this value.
- Name->Destroy();
- Name = nullptr;
+ destroyValueName();
return;
}
- if (Name)
- Name->Destroy();
-
// NOTE: Could optimize for the case the name is shrinking to not deallocate
// then reallocated.
+ destroyValueName();
// Create the new name.
- Name = ValueName::Create(NameRef.begin(), NameRef.end());
- Name->setValue(this);
+ setValueName(ValueName::Create(NameRef));
+ getValueName()->setValue(this);
return;
}
// then reallocated.
if (hasName()) {
// Remove old name.
- ST->removeValueName(Name);
- Name->Destroy();
- Name = nullptr;
+ ST->removeValueName(getValueName());
+ destroyValueName();
if (NameRef.empty())
return;
}
// Name is changing to something new.
- Name = ST->createValueName(NameRef, this);
+ setValueName(ST->createValueName(NameRef, this));
}
-
-/// takeName - transfer the name from V to this value, setting V's name to
-/// empty. It is an error to call V->takeName(V).
void Value::takeName(Value *V) {
- assert(SubclassID != MDStringVal && "Cannot take the name of an MDString!");
-
ValueSymbolTable *ST = nullptr;
// If this value has a name, drop it.
if (hasName()) {
// Remove old name.
if (ST)
- ST->removeValueName(Name);
- Name->Destroy();
- Name = nullptr;
+ ST->removeValueName(getValueName());
+ destroyValueName();
}
// Now we know that this has no name.
// This works even if both values have no symtab yet.
if (ST == VST) {
// Take the name!
- Name = V->Name;
- V->Name = nullptr;
- Name->setValue(this);
+ setValueName(V->getValueName());
+ V->setValueName(nullptr);
+ getValueName()->setValue(this);
return;
}
// then reinsert it into ST.
if (VST)
- VST->removeValueName(V->Name);
- Name = V->Name;
- V->Name = nullptr;
- Name->setValue(this);
+ VST->removeValueName(V->getValueName());
+ setValueName(V->getValueName());
+ V->setValueName(nullptr);
+ getValueName()->setValue(this);
if (ST)
ST->reinsertValue(this);
}
-static GlobalObject &findReplacementForAliasUse(Value &C) {
- if (auto *GO = dyn_cast<GlobalObject>(&C))
- return *GO;
- if (auto *GA = dyn_cast<GlobalAlias>(&C))
- return *GA->getAliasee();
- auto *CE = cast<ConstantExpr>(&C);
- assert(CE->getOpcode() == Instruction::BitCast ||
- CE->getOpcode() == Instruction::GetElementPtr ||
- CE->getOpcode() == Instruction::AddrSpaceCast);
- if (CE->getOpcode() == Instruction::GetElementPtr)
- assert(cast<GEPOperator>(CE)->hasAllZeroIndices());
- return findReplacementForAliasUse(*CE->getOperand(0));
-}
-
-static void replaceAliasUseWith(Use &U, Value *New) {
- GlobalObject &Replacement = findReplacementForAliasUse(*New);
- assert(&cast<GlobalObject>(*U) != &Replacement &&
- "replaceAliasUseWith cannot form an alias cycle");
- U.set(&Replacement);
-}
-
#ifndef NDEBUG
-static bool contains(SmallPtrSet<ConstantExpr *, 4> &Cache, ConstantExpr *Expr,
+static bool contains(SmallPtrSetImpl<ConstantExpr *> &Cache, ConstantExpr *Expr,
Constant *C) {
- if (!Cache.insert(Expr))
+ if (!Cache.insert(Expr).second)
return false;
for (auto &O : Expr->operands()) {
// Notify all ValueHandles (if present) that this value is going away.
if (HasValueHandle)
ValueHandleBase::ValueIsRAUWd(this, New);
+ if (isUsedByMetadata())
+ ValueAsMetadata::handleRAUW(this, New);
while (!use_empty()) {
Use &U = *UseList;
// Must handle Constants specially, we cannot call replaceUsesOfWith on a
// constant because they are uniqued.
if (auto *C = dyn_cast<Constant>(U.getUser())) {
- if (isa<GlobalAlias>(C)) {
- replaceAliasUseWith(U, New);
- continue;
- }
if (!isa<GlobalValue>(C)) {
C->replaceUsesOfWithOnConstant(this, New, &U);
continue;
BB->replaceSuccessorsPhiUsesWith(cast<BasicBlock>(New));
}
+// Like replaceAllUsesWith except it does not handle constants or basic blocks.
+// This routine leaves uses within BB.
+void Value::replaceUsesOutsideBlock(Value *New, BasicBlock *BB) {
+ assert(New && "Value::replaceUsesOutsideBlock(<null>, BB) is invalid!");
+ assert(!contains(New, this) &&
+ "this->replaceUsesOutsideBlock(expr(this), BB) is NOT valid!");
+ assert(New->getType() == getType() &&
+ "replaceUses of value with new value of different type!");
+ assert(BB && "Basic block that may contain a use of 'New' must be defined\n");
+
+ use_iterator UI = use_begin(), E = use_end();
+ for (; UI != E;) {
+ Use &U = *UI;
+ ++UI;
+ auto *Usr = dyn_cast<Instruction>(U.getUser());
+ if (Usr && Usr->getParent() == BB)
+ continue;
+ U.set(New);
+ }
+ return;
+}
+
namespace {
// Various metrics for how much to strip off of pointers.
enum PointerStripKind {
return V;
}
assert(V->getType()->isPointerTy() && "Unexpected operand type!");
- } while (Visited.insert(V));
+ } while (Visited.insert(V).second);
return V;
}
return V;
Offset = GEPOffset;
V = GEP->getPointerOperand();
- } else if (Operator::getOpcode(V) == Instruction::BitCast) {
+ } else if (Operator::getOpcode(V) == Instruction::BitCast ||
+ Operator::getOpcode(V) == Instruction::AddrSpaceCast) {
V = cast<Operator>(V)->getOperand(0);
} else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
V = GA->getAliasee();
return V;
}
assert(V->getType()->isPointerTy() && "Unexpected operand type!");
- } while (Visited.insert(V));
+ } while (Visited.insert(V).second);
return V;
}
return stripPointerCastsAndOffsets<PSK_InBounds>(this);
}
-/// isDereferenceablePointer - Test if this value is always a pointer to
-/// allocated and suitably aligned memory for a simple load or store.
-static bool isDereferenceablePointer(const Value *V,
- SmallPtrSet<const Value *, 32> &Visited) {
+/// \brief Check if Value is always a dereferenceable pointer.
+///
+/// Test if V is always a pointer to allocated and suitably aligned memory for
+/// a simple load or store.
+static bool isDereferenceablePointer(const Value *V, const DataLayout *DL,
+ SmallPtrSetImpl<const Value *> &Visited) {
// Note that it is not safe to speculate into a malloc'd region because
// malloc may return null.
- // It's also not always safe to follow a bitcast, for example:
- // bitcast i8* (alloca i8) to i32*
- // would result in a 4-byte load from a 1-byte alloca. Some cases could
- // be handled using DataLayout to check sizes and alignments though.
// These are obviously ok.
if (isa<AllocaInst>(V)) return true;
+ // It's not always safe to follow a bitcast, for example:
+ // bitcast i8* (alloca i8) to i32*
+ // would result in a 4-byte load from a 1-byte alloca. However,
+ // if we're casting from a pointer from a type of larger size
+ // to a type of smaller size (or the same size), and the alignment
+ // is at least as large as for the resulting pointer type, then
+ // we can look through the bitcast.
+ if (DL)
+ if (const BitCastOperator *BC = dyn_cast<BitCastOperator>(V)) {
+ Type *STy = BC->getSrcTy()->getPointerElementType(),
+ *DTy = BC->getDestTy()->getPointerElementType();
+ if (STy->isSized() && DTy->isSized() &&
+ (DL->getTypeStoreSize(STy) >=
+ DL->getTypeStoreSize(DTy)) &&
+ (DL->getABITypeAlignment(STy) >=
+ DL->getABITypeAlignment(DTy)))
+ return isDereferenceablePointer(BC->getOperand(0), DL, Visited);
+ }
+
// Global variables which can't collapse to null are ok.
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
return !GV->hasExternalWeakLinkage();
- // byval arguments are ok.
- if (const Argument *A = dyn_cast<Argument>(V))
- return A->hasByValAttr();
+ // byval arguments are okay. Arguments specifically marked as
+ // dereferenceable are okay too.
+ if (const Argument *A = dyn_cast<Argument>(V)) {
+ if (A->hasByValAttr())
+ return true;
+ else if (uint64_t Bytes = A->getDereferenceableBytes()) {
+ Type *Ty = V->getType()->getPointerElementType();
+ if (Ty->isSized() && DL && DL->getTypeStoreSize(Ty) <= Bytes)
+ return true;
+ }
+
+ return false;
+ }
+
+ // Return values from call sites specifically marked as dereferenceable are
+ // also okay.
+ if (ImmutableCallSite CS = V) {
+ if (uint64_t Bytes = CS.getDereferenceableBytes(0)) {
+ Type *Ty = V->getType()->getPointerElementType();
+ if (Ty->isSized() && DL && DL->getTypeStoreSize(Ty) <= Bytes)
+ return true;
+ }
+ }
// For GEPs, determine if the indexing lands within the allocated object.
if (const GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
// Conservatively require that the base pointer be fully dereferenceable.
- if (!Visited.insert(GEP->getOperand(0)))
+ if (!Visited.insert(GEP->getOperand(0)).second)
return false;
- if (!isDereferenceablePointer(GEP->getOperand(0), Visited))
+ if (!isDereferenceablePointer(GEP->getOperand(0), DL, Visited))
return false;
// Check the indices.
gep_type_iterator GTI = gep_type_begin(GEP);
return true;
}
+ // For gc.relocate, look through relocations
+ if (const IntrinsicInst *I = dyn_cast<IntrinsicInst>(V))
+ if (I->getIntrinsicID() == Intrinsic::experimental_gc_relocate) {
+ GCRelocateOperands RelocateInst(I);
+ return isDereferenceablePointer(RelocateInst.derivedPtr(), DL, Visited);
+ }
+
+ if (const AddrSpaceCastInst *ASC = dyn_cast<AddrSpaceCastInst>(V))
+ return isDereferenceablePointer(ASC->getOperand(0), DL, Visited);
+
// If we don't know, assume the worst.
return false;
}
-/// isDereferenceablePointer - Test if this value is always a pointer to
-/// allocated and suitably aligned memory for a simple load or store.
-bool Value::isDereferenceablePointer() const {
+bool Value::isDereferenceablePointer(const DataLayout *DL) const {
+ // When dereferenceability information is provided by a dereferenceable
+ // attribute, we know exactly how many bytes are dereferenceable. If we can
+ // determine the exact offset to the attributed variable, we can use that
+ // information here.
+ Type *Ty = getType()->getPointerElementType();
+ if (Ty->isSized() && DL) {
+ APInt Offset(DL->getTypeStoreSizeInBits(getType()), 0);
+ const Value *BV = stripAndAccumulateInBoundsConstantOffsets(*DL, Offset);
+
+ APInt DerefBytes(Offset.getBitWidth(), 0);
+ if (const Argument *A = dyn_cast<Argument>(BV))
+ DerefBytes = A->getDereferenceableBytes();
+ else if (ImmutableCallSite CS = BV)
+ DerefBytes = CS.getDereferenceableBytes(0);
+
+ if (DerefBytes.getBoolValue() && Offset.isNonNegative()) {
+ if (DerefBytes.uge(Offset + DL->getTypeStoreSize(Ty)))
+ return true;
+ }
+ }
+
SmallPtrSet<const Value *, 32> Visited;
- return ::isDereferenceablePointer(this, Visited);
+ return ::isDereferenceablePointer(this, DL, Visited);
}
-/// DoPHITranslation - If this value is a PHI node with CurBB as its parent,
-/// return the value in the PHI node corresponding to PredBB. If not, return
-/// ourself. This is useful if you want to know the value something has in a
-/// predecessor block.
Value *Value::DoPHITranslation(const BasicBlock *CurBB,
const BasicBlock *PredBB) {
PHINode *PN = dyn_cast<PHINode>(this);
LLVMContext &Value::getContext() const { return VTy->getContext(); }
+void Value::reverseUseList() {
+ if (!UseList || !UseList->Next)
+ // No need to reverse 0 or 1 uses.
+ return;
+
+ Use *Head = UseList;
+ Use *Current = UseList->Next;
+ Head->Next = nullptr;
+ while (Current) {
+ Use *Next = Current->Next;
+ Current->Next = Head;
+ Head->setPrev(&Current->Next);
+ Head = Current;
+ Current = Next;
+ }
+ UseList = Head;
+ Head->setPrev(&UseList);
+}
+
//===----------------------------------------------------------------------===//
// ValueHandleBase Class
//===----------------------------------------------------------------------===//
-/// AddToExistingUseList - Add this ValueHandle to the use list for VP, where
-/// List is known to point into the existing use list.
void ValueHandleBase::AddToExistingUseList(ValueHandleBase **List) {
assert(List && "Handle list is null?");
setPrevPtr(List);
if (Next) {
Next->setPrevPtr(&Next);
- assert(VP.getPointer() == Next->VP.getPointer() && "Added to wrong list?");
+ assert(V == Next->V && "Added to wrong list?");
}
}
Next->setPrevPtr(&Next);
}
-/// AddToUseList - Add this ValueHandle to the use list for VP.
void ValueHandleBase::AddToUseList() {
- assert(VP.getPointer() && "Null pointer doesn't have a use list!");
+ assert(V && "Null pointer doesn't have a use list!");
- LLVMContextImpl *pImpl = VP.getPointer()->getContext().pImpl;
+ LLVMContextImpl *pImpl = V->getContext().pImpl;
- if (VP.getPointer()->HasValueHandle) {
+ if (V->HasValueHandle) {
// If this value already has a ValueHandle, then it must be in the
// ValueHandles map already.
- ValueHandleBase *&Entry = pImpl->ValueHandles[VP.getPointer()];
+ ValueHandleBase *&Entry = pImpl->ValueHandles[V];
assert(Entry && "Value doesn't have any handles?");
AddToExistingUseList(&Entry);
return;
DenseMap<Value*, ValueHandleBase*> &Handles = pImpl->ValueHandles;
const void *OldBucketPtr = Handles.getPointerIntoBucketsArray();
- ValueHandleBase *&Entry = Handles[VP.getPointer()];
+ ValueHandleBase *&Entry = Handles[V];
assert(!Entry && "Value really did already have handles?");
AddToExistingUseList(&Entry);
- VP.getPointer()->HasValueHandle = true;
+ V->HasValueHandle = true;
// If reallocation didn't happen or if this was the first insertion, don't
// walk the table.
// Okay, reallocation did happen. Fix the Prev Pointers.
for (DenseMap<Value*, ValueHandleBase*>::iterator I = Handles.begin(),
E = Handles.end(); I != E; ++I) {
- assert(I->second && I->first == I->second->VP.getPointer() &&
+ assert(I->second && I->first == I->second->V &&
"List invariant broken!");
I->second->setPrevPtr(&I->second);
}
}
-/// RemoveFromUseList - Remove this ValueHandle from its current use list.
void ValueHandleBase::RemoveFromUseList() {
- assert(VP.getPointer() && VP.getPointer()->HasValueHandle &&
+ assert(V && V->HasValueHandle &&
"Pointer doesn't have a use list!");
// Unlink this from its use list.
// If the Next pointer was null, then it is possible that this was the last
// ValueHandle watching VP. If so, delete its entry from the ValueHandles
// map.
- LLVMContextImpl *pImpl = VP.getPointer()->getContext().pImpl;
+ LLVMContextImpl *pImpl = V->getContext().pImpl;
DenseMap<Value*, ValueHandleBase*> &Handles = pImpl->ValueHandles;
if (Handles.isPointerIntoBucketsArray(PrevPtr)) {
- Handles.erase(VP.getPointer());
- VP.getPointer()->HasValueHandle = false;
+ Handles.erase(V);
+ V->HasValueHandle = false;
}
}
void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) {
assert(Old->HasValueHandle &&"Should only be called if ValueHandles present");
assert(Old != New && "Changing value into itself!");
+ assert(Old->getType() == New->getType() &&
+ "replaceAllUses of value with new value of different type!");
// Get the linked list base, which is guaranteed to exist since the
// HasValueHandle flag is set.