//===----------------------------------------------------------------------===//
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
// Useful predicates
//===----------------------------------------------------------------------===//
-// Determine if an AllocationInst instruction escapes from the function it is
-// contained in. If it does not escape, there is no way for another function to
-// mod/ref it. We do this by looking at its uses and determining if the uses
-// can escape (recursively).
-static bool AddressMightEscape(const Value *V) {
- for (Value::use_const_iterator UI = V->use_begin(), E = V->use_end();
- UI != E; ++UI) {
- const Instruction *I = cast<Instruction>(*UI);
- switch (I->getOpcode()) {
- case Instruction::Load:
- break; //next use.
- case Instruction::Store:
- if (I->getOperand(0) == V)
- return true; // Escapes if the pointer is stored.
- break; // next use.
- case Instruction::GetElementPtr:
- if (AddressMightEscape(I))
- return true;
- break; // next use.
- case Instruction::BitCast:
- if (AddressMightEscape(I))
- return true;
- break; // next use
- case Instruction::Ret:
- // If returned, the address will escape to calling functions, but no
- // callees could modify it.
- break; // next use
- case Instruction::Call:
- // If the call is to a few known safe intrinsics, we know that it does
- // not escape.
- // TODO: Eventually just check the 'nocapture' attribute.
- if (!isa<MemIntrinsic>(I))
- return true;
- break; // next use
- default:
- return true;
- }
- }
- return false;
-}
-
static const User *isGEP(const Value *V) {
if (isa<GetElementPtrInst>(V) ||
(isa<ConstantExpr>(V) &&
return V;
}
-/// isNoAliasCall - Return true if this pointer is returned by a noalias
-/// function.
-static bool isNoAliasCall(const Value *V) {
- if (isa<CallInst>(V) || isa<InvokeInst>(V))
- return CallSite(const_cast<Instruction*>(cast<Instruction>(V)))
- .paramHasAttr(0, Attribute::NoAlias);
- return false;
-}
-
-/// isIdentifiedObject - Return true if this pointer refers to a distinct and
-/// identifiable object. This returns true for:
-/// Global Variables and Functions
-/// Allocas and Mallocs
-/// ByVal and NoAlias Arguments
-/// NoAlias returns
-///
-static bool isIdentifiedObject(const Value *V) {
- if (isa<GlobalValue>(V) || isa<AllocationInst>(V) || isNoAliasCall(V))
- return true;
- if (const Argument *A = dyn_cast<Argument>(V))
- return A->hasNoAliasAttr() || A->hasByValAttr();
- return false;
-}
-
/// isKnownNonNull - Return true if we know that the specified value is never
/// null.
static bool isKnownNonNull(const Value *V) {
static bool isNonEscapingLocalObject(const Value *V) {
// If this is a local allocation, check to see if it escapes.
if (isa<AllocationInst>(V) || isNoAliasCall(V))
- return !AddressMightEscape(V);
-
+ return !PointerMayBeCaptured(V, false);
+
// If this is an argument that corresponds to a byval or noalias argument,
- // it can't escape either.
+ // then it has not escaped before entering the function. Check if it escapes
+ // inside the function.
if (const Argument *A = dyn_cast<Argument>(V))
- if (A->hasByValAttr() || A->hasNoAliasAttr())
- return !AddressMightEscape(V);
+ if (A->hasByValAttr() || A->hasNoAliasAttr()) {
+ // Don't bother analyzing arguments already known not to escape.
+ if (A->hasNoCaptureAttr())
+ return true;
+ return !PointerMayBeCaptured(V, false);
+ }
return false;
}
}
if (AccessTy->isSized())
- return TD.getABITypeSize(AccessTy) < Size;
+ return TD.getTypePaddedSize(AccessTy) < Size;
return false;
}
return MayAlias;
}
- virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS,
- std::vector<PointerAccessInfo> *Info) {
- return UnknownModRefBehavior;
- }
-
virtual void getArgumentAccesses(Function *F, CallSite CS,
std::vector<PointerAccessInfo> &Info) {
assert(0 && "This method may not be called on this function!");
ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
ModRefResult getModRefInfo(CallSite CS1, CallSite CS2);
-
+
/// hasNoModRefInfoForCalls - We can provide mod/ref information against
/// non-escaping allocations.
virtual bool hasNoModRefInfoForCalls() const { return false; }
return false;
}
+
// getModRefInfo - Check to see if the specified callsite can clobber the
// specified memory object. Since we only look at local properties of this
// function, we really can't say much about this query. We do, however, use
// If the pointer is to a locally allocated object that does not escape,
// then the call can not mod/ref the pointer unless the call takes the
// argument without capturing it.
- if (isNonEscapingLocalObject(Object)) {
+ if (isNonEscapingLocalObject(Object) && CS.getInstruction() != Object) {
bool passedAsArg = false;
// TODO: Eventually only check 'nocapture' arguments.
for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
// non-escaping local object, then we know the object couldn't escape to a
// point where the call could return it.
if ((isa<CallInst>(O1) || isa<InvokeInst>(O1)) &&
- isNonEscapingLocalObject(O2))
+ isNonEscapingLocalObject(O2) && O1 != O2)
return NoAlias;
if ((isa<CallInst>(O2) || isa<InvokeInst>(O2)) &&
- isNonEscapingLocalObject(O1))
+ isNonEscapingLocalObject(O1) && O1 != O2)
return NoAlias;
// If we have two gep instructions with must-alias'ing base pointers, figure
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