//===----------------------------------------------------------------------===//
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CaptureTracking.h"
-#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(const AtomicCmpXchgInst *CX, const Location &Loc) {
// Acquire/Release cmpxchg has properties that matter for arbitrary addresses.
- if (CX->getOrdering() > Monotonic)
+ if (CX->getSuccessOrdering() > Monotonic)
return ModRef;
// If the cmpxchg address does not alias the location, it does not access it.
}
namespace {
- // Conservatively return true. Return false, if there is a single path
- // starting from "From" and the path does not reach "To".
- static bool hasPath(const BasicBlock *From, const BasicBlock *To) {
- const unsigned MaxCheck = 5;
- const BasicBlock *Current = From;
- for (unsigned I = 0; I < MaxCheck; I++) {
- unsigned NumSuccs = Current->getTerminator()->getNumSuccessors();
- if (NumSuccs > 1)
- return true;
- if (NumSuccs == 0)
- return false;
- Current = Current->getTerminator()->getSuccessor(0);
- if (Current == To)
- return true;
- }
- return true;
- }
-
/// Only find pointer captures which happen before the given instruction. Uses
/// the dominator tree to determine whether one instruction is before another.
/// Only support the case where the Value is defined in the same basic block
CapturesBefore(const Instruction *I, DominatorTree *DT)
: BeforeHere(I), DT(DT), Captured(false) {}
- void tooManyUses() { Captured = true; }
+ void tooManyUses() override { Captured = true; }
- bool shouldExplore(Use *U) {
+ bool shouldExplore(const Use *U) override {
Instruction *I = cast<Instruction>(U->getUser());
BasicBlock *BB = I->getParent();
// We explore this usage only if the usage can reach "BeforeHere".
// there is no need to explore the use if BeforeHere dominates use.
// Check whether there is a path from I to BeforeHere.
if (BeforeHere != I && DT->dominates(BeforeHere, I) &&
- !hasPath(BB, BeforeHere->getParent()))
+ !isPotentiallyReachable(I, BeforeHere, DT))
return false;
return true;
}
- bool captured(Use *U) {
+ bool captured(const Use *U) override {
Instruction *I = cast<Instruction>(U->getUser());
BasicBlock *BB = I->getParent();
// Same logic as in shouldExplore.
if (BeforeHere != I && !DT->isReachableFromEntry(BB))
return false;
if (BeforeHere != I && DT->dominates(BeforeHere, I) &&
- !hasPath(BB, BeforeHere->getParent()))
+ !isPotentiallyReachable(I, BeforeHere, DT))
return false;
Captured = true;
return true;
AliasAnalysis::callCapturesBefore(const Instruction *I,
const AliasAnalysis::Location &MemLoc,
DominatorTree *DT) {
- if (!DT || !TD) return AliasAnalysis::ModRef;
+ if (!DT || !DL) return AliasAnalysis::ModRef;
- const Value *Object = GetUnderlyingObject(MemLoc.Ptr, TD);
+ const Value *Object = GetUnderlyingObject(MemLoc.Ptr, DL);
if (!isIdentifiedObject(Object) || isa<GlobalValue>(Object) ||
isa<Constant>(Object))
return AliasAnalysis::ModRef;
return AliasAnalysis::ModRef;
unsigned ArgNo = 0;
+ AliasAnalysis::ModRefResult R = AliasAnalysis::NoModRef;
for (ImmutableCallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
CI != CE; ++CI, ++ArgNo) {
// Only look at the no-capture or byval pointer arguments. If this
// is impossible to alias the pointer we're checking. If not, we have to
// assume that the call could touch the pointer, even though it doesn't
// escape.
- if (!isNoAlias(AliasAnalysis::Location(*CI),
- AliasAnalysis::Location(Object))) {
- return AliasAnalysis::ModRef;
+ if (isNoAlias(AliasAnalysis::Location(*CI),
+ AliasAnalysis::Location(Object)))
+ continue;
+ if (CS.doesNotAccessMemory(ArgNo))
+ continue;
+ if (CS.onlyReadsMemory(ArgNo)) {
+ R = AliasAnalysis::Ref;
+ continue;
}
+ return AliasAnalysis::ModRef;
}
- return AliasAnalysis::NoModRef;
+ return R;
}
// AliasAnalysis destructor: DO NOT move this to the header file for
/// AliasAnalysis interface before any other methods are called.
///
void AliasAnalysis::InitializeAliasAnalysis(Pass *P) {
- TD = P->getAnalysisIfAvailable<DataLayout>();
+ DataLayoutPass *DLP = P->getAnalysisIfAvailable<DataLayoutPass>();
+ DL = DLP ? &DLP->getDataLayout() : nullptr;
TLI = P->getAnalysisIfAvailable<TargetLibraryInfo>();
AA = &P->getAnalysis<AliasAnalysis>();
}
/// if known, or a conservative value otherwise.
///
uint64_t AliasAnalysis::getTypeStoreSize(Type *Ty) {
- return TD ? TD->getTypeStoreSize(Ty) : UnknownSize;
+ return DL ? DL->getTypeStoreSize(Ty) : UnknownSize;
}
/// canBasicBlockModify - Return true if it is possible for execution of the
return false;
}
+/// isNoAliasArgument - Return true if this is an argument with the noalias
+/// attribute.
+bool llvm::isNoAliasArgument(const Value *V)
+{
+ if (const Argument *A = dyn_cast<Argument>(V))
+ return A->hasNoAliasAttr();
+ return false;
+}
+
/// isIdentifiedObject - Return true if this pointer refers to a distinct and
/// identifiable object. This returns true for:
/// Global Variables and Functions (but not Global Aliases)
return A->hasNoAliasAttr() || A->hasByValAttr();
return false;
}
-
-/// isKnownNonNull - Return true if we know that the specified value is never
-/// null.
-bool llvm::isKnownNonNull(const Value *V) {
- // Alloca never returns null, malloc might.
- if (isa<AllocaInst>(V)) return true;
-
- // A byval argument is never null.
- if (const Argument *A = dyn_cast<Argument>(V))
- return A->hasByValAttr();
-
- // Global values are not null unless extern weak.
- if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
- return !GV->hasExternalWeakLinkage();
- return false;
-}
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