// chain. For example:
// A[i][0] != A[j][1] iff (&A[0][1]-&A[0][0] >= std::max(G1S, G2S))
//
+ // We have to be careful here about array accesses. In particular, consider:
+ // A[1][0] vs A[0][i]
+ // In this case, we don't *know* that the array will be accessed in bounds:
+ // the index could even be negative. Because of this, we have to
+ // conservatively *give up* and return may alias. We disregard differing
+ // array subscripts that are followed by a variable index without going
+ // through a struct.
+ //
unsigned SizeMax = std::max(G1S, G2S);
if (SizeMax == ~0U) return MayAlias; // Avoid frivolous work.
GEP1Ops[FirstConstantOper] = G1OC;
GEP2Ops[FirstConstantOper] = G2OC;
}
-
+
if (G1OC != G2OC) {
+ // Handle the "be careful" case above: if this is an array
+ // subscript, scan for a subsequent variable array index.
+ if (isa<ArrayType>(BasePtr1Ty)) {
+ const Type *NextTy =cast<ArrayType>(BasePtr1Ty)->getElementType();
+ bool isBadCase = false;
+
+ for (unsigned Idx = FirstConstantOper+1;
+ Idx != MinOperands && isa<ArrayType>(NextTy); ++Idx) {
+ const Value *V1 = GEP1Ops[Idx], *V2 = GEP2Ops[Idx];
+ if (!isa<Constant>(V1) || !isa<Constant>(V2)) {
+ isBadCase = true;
+ break;
+ }
+ NextTy = cast<ArrayType>(NextTy)->getElementType();
+ }
+
+ if (isBadCase) G1OC = 0;
+ }
+
// Make sure they are comparable (ie, not constant expressions), and
// make sure the GEP with the smaller leading constant is GEP1.
- Constant *Compare = ConstantExpr::getSetGT(G1OC, G2OC);
- if (ConstantBool *CV = dyn_cast<ConstantBool>(Compare)) {
- if (CV->getValue()) // If they are comparable and G2 > G1
- std::swap(GEP1Ops, GEP2Ops); // Make GEP1 < GEP2
- break;
+ if (G1OC) {
+ Constant *Compare = ConstantExpr::getSetGT(G1OC, G2OC);
+ if (ConstantBool *CV = dyn_cast<ConstantBool>(Compare)) {
+ if (CV->getValue()) // If they are comparable and G2 > G1
+ std::swap(GEP1Ops, GEP2Ops); // Make GEP1 < GEP2
+ break;
+ }
}
}
}
// than the first constant index of GEP2.
// Advance BasePtr[12]Ty over this first differing constant operand.
- BasePtr2Ty = cast<CompositeType>(BasePtr1Ty)->getTypeAtIndex(GEP2Ops[FirstConstantOper]);
- BasePtr1Ty = cast<CompositeType>(BasePtr1Ty)->getTypeAtIndex(GEP1Ops[FirstConstantOper]);
+ BasePtr2Ty = cast<CompositeType>(BasePtr1Ty)->
+ getTypeAtIndex(GEP2Ops[FirstConstantOper]);
+ BasePtr1Ty = cast<CompositeType>(BasePtr1Ty)->
+ getTypeAtIndex(GEP1Ops[FirstConstantOper]);
// We are going to be using TargetData::getIndexedOffset to determine the
// offset that each of the GEP's is reaching. To do this, we have to convert
// all variable references to constant references. To do this, we convert the
- // initial equal sequence of variables into constant zeros to start with.
- for (unsigned i = 0; i != FirstConstantOper; ++i)
- if (!isa<ConstantInt>(GEP1Ops[i]) || !isa<ConstantInt>(GEP2Ops[i]))
+ // initial sequence of array subscripts into constant zeros to start with.
+ const Type *ZeroIdxTy = GEPPointerTy;
+ for (unsigned i = 0; i != FirstConstantOper; ++i) {
+ if (!isa<StructType>(ZeroIdxTy))
GEP1Ops[i] = GEP2Ops[i] = Constant::getNullValue(Type::UIntTy);
+ if (const CompositeType *CT = dyn_cast<CompositeType>(ZeroIdxTy))
+ ZeroIdxTy = CT->getTypeAtIndex(GEP1Ops[i]);
+ }
+
// We know that GEP1Ops[FirstConstantOper] & GEP2Ops[FirstConstantOper] are ok
// Loop over the rest of the operands...
// Note that this list cannot contain libm functions (such as acos and sqrt)
// that set errno on a domain or other error.
-static const char *DoesntAccessMemoryTable[] = {
- // LLVM intrinsics:
- "llvm.frameaddress", "llvm.returnaddress", "llvm.readport",
- "llvm.isunordered", "llvm.sqrt", "llvm.ctpop", "llvm.ctlz", "llvm.cttz",
-
+static const char *DoesntAccessMemoryFns[] = {
"abs", "labs", "llabs", "imaxabs", "fabs", "fabsf", "fabsl",
"trunc", "truncf", "truncl", "ldexp",
"hypot",
"sin", "sinf", "sinl",
"tan", "tanf", "tanl", "tanh", "tanhf", "tanhl",
+
+ "floor", "floorf", "floorl", "ceil", "ceilf", "ceill",
// ctype.h
"isalnum", "isalpha", "iscntrl", "isdigit", "isgraph", "islower", "isprint"
"__signbit", "__signbitf", "__signbitl",
};
-static const unsigned DAMTableSize =
- sizeof(DoesntAccessMemoryTable)/sizeof(DoesntAccessMemoryTable[0]);
-static const char *OnlyReadsMemoryTable[] = {
+static const char *OnlyReadsMemoryFns[] = {
"atoi", "atol", "atof", "atoll", "atoq", "a64l",
"bcmp", "memcmp", "memchr", "memrchr", "wmemcmp", "wmemchr",
"feof_unlocked", "ferror_unlocked", "fileno_unlocked"
};
-static const unsigned ORMTableSize =
- sizeof(OnlyReadsMemoryTable)/sizeof(OnlyReadsMemoryTable[0]);
-
AliasAnalysis::ModRefBehavior
BasicAliasAnalysis::getModRefBehavior(Function *F, CallSite CS,
std::vector<PointerAccessInfo> *Info) {
if (!F->isExternal()) return UnknownModRefBehavior;
+ static std::vector<const char*> NoMemoryTable, OnlyReadsMemoryTable;
+
static bool Initialized = false;
if (!Initialized) {
+ NoMemoryTable.insert(NoMemoryTable.end(),
+ DoesntAccessMemoryFns,
+ DoesntAccessMemoryFns+
+ sizeof(DoesntAccessMemoryFns)/sizeof(DoesntAccessMemoryFns[0]));
+
+ OnlyReadsMemoryTable.insert(OnlyReadsMemoryTable.end(),
+ OnlyReadsMemoryFns,
+ OnlyReadsMemoryFns+
+ sizeof(OnlyReadsMemoryFns)/sizeof(OnlyReadsMemoryFns[0]));
+#define GET_MODREF_BEHAVIOR
+#include "llvm/Intrinsics.gen"
+#undef GET_MODREF_BEHAVIOR
+
// Sort the table the first time through.
- std::sort(DoesntAccessMemoryTable, DoesntAccessMemoryTable+DAMTableSize,
- StringCompare());
- std::sort(OnlyReadsMemoryTable, OnlyReadsMemoryTable+ORMTableSize,
+ std::sort(NoMemoryTable.begin(), NoMemoryTable.end(), StringCompare());
+ std::sort(OnlyReadsMemoryTable.begin(), OnlyReadsMemoryTable.end(),
StringCompare());
Initialized = true;
}
- const char **Ptr = std::lower_bound(DoesntAccessMemoryTable,
- DoesntAccessMemoryTable+DAMTableSize,
- F->getName().c_str(), StringCompare());
- if (Ptr != DoesntAccessMemoryTable+DAMTableSize && *Ptr == F->getName())
+ std::vector<const char*>::iterator Ptr =
+ std::lower_bound(NoMemoryTable.begin(), NoMemoryTable.end(),
+ F->getName().c_str(), StringCompare());
+ if (Ptr != NoMemoryTable.end() && *Ptr == F->getName())
return DoesNotAccessMemory;
- Ptr = std::lower_bound(OnlyReadsMemoryTable,
- OnlyReadsMemoryTable+ORMTableSize,
+ Ptr = std::lower_bound(OnlyReadsMemoryTable.begin(),
+ OnlyReadsMemoryTable.end(),
F->getName().c_str(), StringCompare());
- if (Ptr != OnlyReadsMemoryTable+ORMTableSize && *Ptr == F->getName())
+ if (Ptr != OnlyReadsMemoryTable.end() && *Ptr == F->getName())
return OnlyReadsMemory;
return UnknownModRefBehavior;
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