#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"
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), Name(nullptr), SubclassID(scid),
+ HasValueHandle(0), SubclassOptionalData(0), SubclassData(0) {
// FIXME: Why isn't this in the subclass gunk??
// Note, we cannot call isa<CallInst> before the CallInst has been
// constructed.
// then reallocated.
// Create the new name.
- Name = ValueName::Create(NameRef.begin(), NameRef.end());
+ Name = ValueName::Create(NameRef);
Name->setValue(this);
return;
}
}
#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))
return false;
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();
/// 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) {
+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 BitCastInst* BC = dyn_cast<BitCastInst>(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)))
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;
}
+ 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,
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
//===----------------------------------------------------------------------===//
projects / oota-llvm.git / blobdiff