Add lint checks for function attributes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105009 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 91 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.