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-rw-r--r--lib/Analysis/Lint.cpp121
-rw-r--r--test/Other/lint.ll17
2 files changed, 108 insertions, 30 deletions
diff --git a/lib/Analysis/Lint.cpp b/lib/Analysis/Lint.cpp
index 91929be346..1e836af1c5 100644
--- a/lib/Analysis/Lint.cpp
+++ b/lib/Analysis/Lint.cpp
@@ -68,7 +68,8 @@ namespace {
void visitFunction(Function &F);
void visitCallSite(CallSite CS);
- void visitMemoryReference(Instruction &I, Value *Ptr, unsigned Align,
+ void visitMemoryReference(Instruction &I, Value *Ptr,
+ unsigned Size, unsigned Align,
const Type *Ty, unsigned Flags);
void visitCallInst(CallInst &I);
@@ -205,7 +206,7 @@ void Lint::visitCallSite(CallSite CS) {
Instruction &I = *CS.getInstruction();
Value *Callee = CS.getCalledValue();
- visitMemoryReference(I, Callee, 0, 0, MemRef::Callee);
+ visitMemoryReference(I, Callee, ~0u, 0, 0, MemRef::Callee);
if (Function *F = dyn_cast<Function>(findValue(Callee, /*OffsetOk=*/false))) {
Assert1(CS.getCallingConv() == F->getCallingConv(),
@@ -214,20 +215,45 @@ void Lint::visitCallSite(CallSite CS) {
const FunctionType *FT = F->getFunctionType();
unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin());
+ std::vector<Value *> NoAliasVals;
Assert1(FT->isVarArg() ?
FT->getNumParams() <= NumActualArgs :
FT->getNumParams() == NumActualArgs,
"Undefined behavior: Call argument count mismatches callee "
"argument count", &I);
-
- // TODO: Check argument types (in case the callee was casted)
- // TODO: Check ABI-significant attributes.
-
- // TODO: Check noalias attribute.
+ // Check argument types (in case the callee was casted) and attributes.
+ Function::arg_iterator PI = F->arg_begin(), PE = F->arg_end();
+ CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+ for (; AI != AE; ++AI) {
+ Value *Actual = *AI;
+ if (PI != PE) {
+ Argument *Formal = PI++;
+ Assert1(Formal->getType() == Actual->getType(),
+ "Undefined behavior: Call argument type mismatches "
+ "callee parameter type", &I);
+ if (Formal->hasNoAliasAttr() && Actual->getType()->isPointerTy())
+ NoAliasVals.push_back(Actual);
+ if (Formal->hasStructRetAttr() && Actual->getType()->isPointerTy()) {
+ const Type *Ty =
+ cast<PointerType>(Formal->getType())->getElementType();
+ visitMemoryReference(I, Actual, AA->getTypeStoreSize(Ty),
+ TD ? TD->getABITypeAlignment(Ty) : 0,
+ Ty, MemRef::Read | MemRef::Write);
+ }
+ }
+ }
- // TODO: Check sret attribute.
+ // Check that the noalias arguments don't overlap. The AliasAnalysis API
+ // isn't expressive enough for what we really want to do. Known partial
+ // overlap is not distinguished from the case where nothing is known.
+ for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+ AI != AE; ++AI)
+ for (std::vector<Value *>::iterator J = NoAliasVals.begin(),
+ E = NoAliasVals.end(); J != E; ++J)
+ Assert1(AA->alias(*J, ~0u, *AI, ~0u) != AliasAnalysis::MustAlias,
+ "Unusual: noalias argument aliases another argument", &I);
}
if (CS.isCall() && cast<CallInst>(CS.getInstruction())->isTailCall())
@@ -248,9 +274,10 @@ void Lint::visitCallSite(CallSite CS) {
case Intrinsic::memcpy: {
MemCpyInst *MCI = cast<MemCpyInst>(&I);
- visitMemoryReference(I, MCI->getDest(), MCI->getAlignment(), 0,
+ // TODO: If the size is known, use it.
+ visitMemoryReference(I, MCI->getDest(), ~0u, MCI->getAlignment(), 0,
MemRef::Write);
- visitMemoryReference(I, MCI->getSource(), MCI->getAlignment(), 0,
+ visitMemoryReference(I, MCI->getSource(), ~0u, MCI->getAlignment(), 0,
MemRef::Read);
// Check that the memcpy arguments don't overlap. The AliasAnalysis API
@@ -269,15 +296,17 @@ void Lint::visitCallSite(CallSite CS) {
}
case Intrinsic::memmove: {
MemMoveInst *MMI = cast<MemMoveInst>(&I);
- visitMemoryReference(I, MMI->getDest(), MMI->getAlignment(), 0,
+ // TODO: If the size is known, use it.
+ visitMemoryReference(I, MMI->getDest(), ~0u, MMI->getAlignment(), 0,
MemRef::Write);
- visitMemoryReference(I, MMI->getSource(), MMI->getAlignment(), 0,
+ visitMemoryReference(I, MMI->getSource(), ~0u, MMI->getAlignment(), 0,
MemRef::Read);
break;
}
case Intrinsic::memset: {
MemSetInst *MSI = cast<MemSetInst>(&I);
- visitMemoryReference(I, MSI->getDest(), MSI->getAlignment(), 0,
+ // TODO: If the size is known, use it.
+ visitMemoryReference(I, MSI->getDest(), ~0u, MSI->getAlignment(), 0,
MemRef::Write);
break;
}
@@ -287,15 +316,15 @@ void Lint::visitCallSite(CallSite CS) {
"Undefined behavior: va_start called in a non-varargs function",
&I);
- visitMemoryReference(I, CS.getArgument(0), 0, 0,
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
break;
case Intrinsic::vacopy:
- visitMemoryReference(I, CS.getArgument(0), 0, 0, MemRef::Write);
- visitMemoryReference(I, CS.getArgument(1), 0, 0, MemRef::Read);
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0, MemRef::Write);
+ visitMemoryReference(I, CS.getArgument(1), ~0u, 0, 0, MemRef::Read);
break;
case Intrinsic::vaend:
- visitMemoryReference(I, CS.getArgument(0), 0, 0,
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
break;
@@ -303,7 +332,7 @@ void Lint::visitCallSite(CallSite CS) {
// Stackrestore doesn't read or write memory, but it sets the
// stack pointer, which the compiler may read from or write to
// at any time, so check it for both readability and writeability.
- visitMemoryReference(I, CS.getArgument(0), 0, 0,
+ visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
break;
}
@@ -330,15 +359,26 @@ void Lint::visitReturnInst(ReturnInst &I) {
}
}
-// TODO: Add a length argument and check that the reference is in bounds
+// TODO: Check that the reference is in bounds.
void Lint::visitMemoryReference(Instruction &I,
- Value *Ptr, unsigned Align, const Type *Ty,
- unsigned Flags) {
+ Value *Ptr, unsigned Size, unsigned Align,
+ const Type *Ty, unsigned Flags) {
+ // If no memory is being referenced, it doesn't matter if the pointer
+ // is valid.
+ if (Size == 0)
+ return;
+
Value *UnderlyingObject = findValue(Ptr, /*OffsetOk=*/true);
Assert1(!isa<ConstantPointerNull>(UnderlyingObject),
"Undefined behavior: Null pointer dereference", &I);
Assert1(!isa<UndefValue>(UnderlyingObject),
"Undefined behavior: Undef pointer dereference", &I);
+ Assert1(!isa<ConstantInt>(UnderlyingObject) ||
+ !cast<ConstantInt>(UnderlyingObject)->isAllOnesValue(),
+ "Unusual: All-ones pointer dereference", &I);
+ Assert1(!isa<ConstantInt>(UnderlyingObject) ||
+ !cast<ConstantInt>(UnderlyingObject)->isOne(),
+ "Unusual: Address one pointer dereference", &I);
if (Flags & MemRef::Write) {
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(UnderlyingObject))
@@ -379,13 +419,16 @@ void Lint::visitMemoryReference(Instruction &I,
}
void Lint::visitLoadInst(LoadInst &I) {
- visitMemoryReference(I, I.getPointerOperand(), I.getAlignment(), I.getType(),
- MemRef::Read);
+ visitMemoryReference(I, I.getPointerOperand(),
+ AA->getTypeStoreSize(I.getType()), I.getAlignment(),
+ I.getType(), MemRef::Read);
}
void Lint::visitStoreInst(StoreInst &I) {
- visitMemoryReference(I, I.getPointerOperand(), I.getAlignment(),
- I.getOperand(0)->getType(), MemRef::Write);
+ visitMemoryReference(I, I.getPointerOperand(),
+ AA->getTypeStoreSize(I.getOperand(0)->getType()),
+ I.getAlignment(),
+ I.getOperand(0)->getType(), MemRef::Write);
}
void Lint::visitXor(BinaryOperator &I) {
@@ -460,12 +503,12 @@ void Lint::visitAllocaInst(AllocaInst &I) {
}
void Lint::visitVAArgInst(VAArgInst &I) {
- visitMemoryReference(I, I.getOperand(0), 0, 0,
+ visitMemoryReference(I, I.getOperand(0), ~0u, 0, 0,
MemRef::Read | MemRef::Write);
}
void Lint::visitIndirectBrInst(IndirectBrInst &I) {
- visitMemoryReference(I, I.getAddress(), 0, 0, MemRef::Branchee);
+ visitMemoryReference(I, I.getAddress(), ~0u, 0, 0, MemRef::Branchee);
}
void Lint::visitExtractElementInst(ExtractElementInst &I) {
@@ -513,6 +556,7 @@ Value *Lint::findValueImpl(Value *V, bool OffsetOk,
// TODO: Look through sext or zext cast, when the result is known to
// be interpreted as signed or unsigned, respectively.
+ // TODO: Look through eliminable cast pairs.
// TODO: Look through calls with unique return values.
// TODO: Look through vector insert/extract/shuffle.
V = OffsetOk ? V->getUnderlyingObject() : V->stripPointerCasts();
@@ -530,19 +574,36 @@ Value *Lint::findValueImpl(Value *V, bool OffsetOk,
if (!BB) break;
BBI = BB->end();
}
+ } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ if (Value *W = PN->hasConstantValue(DT))
+ return findValueImpl(W, OffsetOk, Visited);
} else if (CastInst *CI = dyn_cast<CastInst>(V)) {
if (CI->isNoopCast(TD ? TD->getIntPtrType(V->getContext()) :
Type::getInt64Ty(V->getContext())))
return findValueImpl(CI->getOperand(0), OffsetOk, Visited);
- } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
- if (Value *W = PN->hasConstantValue(DT))
- return findValueImpl(W, OffsetOk, Visited);
} else if (ExtractValueInst *Ex = dyn_cast<ExtractValueInst>(V)) {
if (Value *W = FindInsertedValue(Ex->getAggregateOperand(),
Ex->idx_begin(),
Ex->idx_end()))
if (W != V)
return findValueImpl(W, OffsetOk, Visited);
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ // Same as above, but for ConstantExpr instead of Instruction.
+ if (Instruction::isCast(CE->getOpcode())) {
+ if (CastInst::isNoopCast(Instruction::CastOps(CE->getOpcode()),
+ CE->getOperand(0)->getType(),
+ CE->getType(),
+ TD ? TD->getIntPtrType(V->getContext()) :
+ Type::getInt64Ty(V->getContext())))
+ return findValueImpl(CE->getOperand(0), OffsetOk, Visited);
+ } else if (CE->getOpcode() == Instruction::ExtractValue) {
+ const SmallVector<unsigned, 4> &Indices = CE->getIndices();
+ if (Value *W = FindInsertedValue(CE->getOperand(0),
+ Indices.begin(),
+ Indices.end()))
+ if (W != V)
+ return findValueImpl(W, OffsetOk, Visited);
+ }
}
// As a last resort, try SimplifyInstruction or constant folding.
diff --git a/test/Other/lint.ll b/test/Other/lint.ll
index bed3dba3a5..9a10abf3c7 100644
--- a/test/Other/lint.ll
+++ b/test/Other/lint.ll
@@ -4,6 +4,9 @@ target datalayout = "e-p:64:64:64"
declare fastcc void @bar()
declare void @llvm.stackrestore(i8*)
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
+declare void @has_sret(i8* sret %p)
+declare void @has_noaliases(i32* noalias %p, i32* %q)
+declare void @one_arg(i32)
@CG = constant i32 7
@@ -18,6 +21,10 @@ define i32 @foo() noreturn {
store i32 0, i32* undef
; CHECK: Undef pointer dereference
%u = load i32* undef
+; CHECK: All-ones pointer dereference
+ store i32 0, i32* inttoptr (i64 -1 to i32*)
+; CHECK: Address one pointer dereference
+ store i32 0, i32* inttoptr (i64 1 to i32*)
; CHECK: Memory reference address is misaligned
%x = inttoptr i32 1 to i32*
load i32* %x, align 4
@@ -54,6 +61,16 @@ define i32 @foo() noreturn {
call void()* bitcast (i8* blockaddress(@foo, %next) to void()*)()
; CHECK: Undefined behavior: Null pointer dereference
call void @llvm.stackrestore(i8* null)
+; CHECK: Undefined behavior: Null pointer dereference
+ call void @has_sret(i8* null)
+; CHECK: Unusual: noalias argument aliases another argument
+ call void @has_noaliases(i32* @CG, i32* @CG)
+; CHECK: Call argument count mismatches callee argument count
+ call void (i32, i32)* bitcast (void (i32)* @one_arg to void (i32, i32)*)(i32 0, i32 0)
+; CHECK: Call argument count mismatches callee argument count
+ call void ()* bitcast (void (i32)* @one_arg to void ()*)()
+; CHECK: Call argument type mismatches callee parameter type
+ call void (float)* bitcast (void (i32)* @one_arg to void (float)*)(float 0.0)
; CHECK: Write to read-only memory
call void @llvm.memcpy.p0i8.p0i8.i64(i8* bitcast (i32* @CG to i8*), i8* bitcast (i32* @CG to i8*), i64 1, i32 1, i1 0)
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-02-19 23:38:46 +0000