Rewrite the function-local validation logic for MDNodes (most of r91708).

Among other benefits, this doesn't leak the SmallPtrSet, has the verifier
code in the verifier pass, actually does the verification at the end,
and is considerably simpler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92217 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Metadata.h

@@ -27,7 +27,6 @@ class LLVMContext;
 class Module;
 class MetadataContextImpl;
 template <typename T> class SmallVectorImpl;
-template<class PtrType, unsigned SmallSize> class SmallPtrSet;
 
 //===----------------------------------------------------------------------===//
 // MetadataBase  - A base class for MDNode, MDString and NamedMDNode.
@@ -91,16 +90,19 @@ class MDNodeElement;
 /// MDNode is always unnamed.
 class MDNode : public MetadataBase, public FoldingSetNode {
   MDNode(const MDNode &);                // DO NOT IMPLEMENT
-
+  void operator=(const MDNode &);        // DO NOT IMPLEMENT
   friend class MDNodeElement;
-  
-  static const unsigned short FunctionLocalBit = 1;
-  
-  // Replace each instance of F from the element list of this node with T.
-  void replaceElement(Value *F, Value *T);
 
   MDNodeElement *Operands;
   unsigned NumOperands;
+  
+  // Subclass data enums.
+  enum {
+    FunctionLocalBit = 1
+  };
+  
+  // Replace each instance of F from the element list of this node with T.
+  void replaceElement(Value *F, Value *T);
 
 protected:
   explicit MDNode(LLVMContext &C, Value *const *Vals, unsigned NumVals,
@@ -125,13 +127,6 @@ public:
   ///       refer to function-local IR.
   bool isFunctionLocal() const { return SubclassData & FunctionLocalBit; }
 
-  /// getLocalFunction - Return false if MDNode's recursive function-localness
-  /// is invalid (local to more than one function).  Return true otherwise.
-  /// If MDNode has one function to which it is local, set LocalFunction to that
-  /// function.
-  bool getLocalFunction(Function *LocalFunction,
-                        SmallPtrSet<MDNode *, 32> *VisitedMDNodes = NULL);
-
   /// Profile - calculate a unique identifier for this MDNode to collapse
   /// duplicates
   void Profile(FoldingSetNodeID &ID) const;

lib/VMCore/Metadata.cpp

@@ -188,46 +188,6 @@ void MDNode::replaceElement(Value *From, Value *To) {
   }
 }
 
-// getLocalFunction - Return false if MDNode's recursive function-localness is
-// invalid (local to more than one function).  Return true otherwise. If MDNode
-// has one function to which it is local, set LocalFunction to that function.
-bool MDNode::getLocalFunction(Function *LocalFunction,
-                              SmallPtrSet<MDNode *, 32> *VisitedMDNodes) {
-  if (!isFunctionLocal())
-    return true;
-    
-  if (!VisitedMDNodes)
-    VisitedMDNodes = new SmallPtrSet<MDNode *, 32>();
-    
-  if (!VisitedMDNodes->insert(this))
-    // MDNode has already been visited, nothing to do.
-    return true;
-
-  for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
-    Value *V = getElement(i);
-    if (!V) continue;
-
-    Function *LocalFunctionTemp = NULL;
-    if (Instruction *I = dyn_cast<Instruction>(V))
-      LocalFunctionTemp = I->getParent()->getParent();
-    else if (MDNode *MD = dyn_cast<MDNode>(V))
-      if (!MD->getLocalFunction(LocalFunctionTemp, VisitedMDNodes))
-        // This MDNode's operand is function-locally invalid or local to a
-        // different function.
-        return false;
-
-    if (LocalFunctionTemp) {
-      if (!LocalFunction)
-        LocalFunction = LocalFunctionTemp;
-      else if (LocalFunction != LocalFunctionTemp)
-        // This MDNode contains operands that are local to different functions.
-        return false;
-    }
-  }
-    
-  return true;
-}
-
 //===----------------------------------------------------------------------===//
 // NamedMDNode implementation.
 //

lib/VMCore/Verifier.cpp

@@ -329,6 +329,8 @@ namespace {
                           int VT, unsigned ArgNo, std::string &Suffix);
     void VerifyIntrinsicPrototype(Intrinsic::ID ID, Function *F,
                                   unsigned RetNum, unsigned ParamNum, ...);
+    void VerifyFunctionLocalMetadata(MDNode *N, Function *F,
+                                     SmallPtrSet<MDNode *, 32> &Visited);
     void VerifyParameterAttrs(Attributes Attrs, const Type *Ty,
                               bool isReturnValue, const Value *V);
     void VerifyFunctionAttrs(const FunctionType *FT, const AttrListPtr &Attrs,
@@ -1526,6 +1528,38 @@ void Verifier::VerifyType(const Type *Ty) {
   }
 }
 
+/// VerifyFunctionLocalMetadata - Verify that the specified MDNode is local to
+/// specified Function.
+void Verifier::VerifyFunctionLocalMetadata(MDNode *N, Function *F,
+                                           SmallPtrSet<MDNode *, 32> &Visited) {
+  assert(N->isFunctionLocal() && "Should only be called on function-local MD");
+
+  // Only visit each node once.
+  if (!Visited.insert(N))
+    return;
+  
+  for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
+    Value *V = N->getElement(i);
+    if (!V) continue;
+    
+    Function *ActualF = 0;
+    if (Instruction *I = dyn_cast<Instruction>(V))
+      ActualF = I->getParent()->getParent();
+    else if (BasicBlock *BB = dyn_cast<BasicBlock>(V))
+      ActualF = BB->getParent();
+    else if (Argument *A = dyn_cast<Argument>(V))
+      ActualF = A->getParent();
+    else if (MDNode *MD = dyn_cast<MDNode>(V))
+      if (MD->isFunctionLocal())
+        VerifyFunctionLocalMetadata(MD, F, Visited);
+
+    // If this was an instruction, bb, or argument, verify that it is in the
+    // function that we expect.
+    Assert1(ActualF == 0 || ActualF == F,
+            "function-local metadata used in wrong function", N);
+  }
+}
+
 // Flags used by TableGen to mark intrinsic parameters with the
 // LLVMExtendedElementVectorType and LLVMTruncatedElementVectorType classes.
 static const unsigned ExtendedElementVectorType = 0x40000000;
@@ -1542,14 +1576,13 @@ void Verifier::visitIntrinsicFunctionCall(Intrinsic::ID ID, CallInst &CI) {
 #include "llvm/Intrinsics.gen"
 #undef GET_INTRINSIC_VERIFIER
 
+  // If the intrinsic takes MDNode arguments, verify that they are either global
+  // or are local to *this* function.
   for (unsigned i = 0, e = CI.getNumOperands(); i != e; ++i)
     if (MDNode *MD = dyn_cast<MDNode>(CI.getOperand(i))) {
-      Function* LocalFunction = NULL;
-      Assert1(MD && MD->getLocalFunction(LocalFunction),
-              "invalid function-local metadata", &CI);
-      if (LocalFunction)
-        Assert1(LocalFunction == CI.getParent()->getParent(),
-                "function-local metadata used in wrong function", &CI);
+      if (!MD->isFunctionLocal()) continue;
+      SmallPtrSet<MDNode *, 32> Visited;
+      VerifyFunctionLocalMetadata(MD, CI.getParent()->getParent(), Visited);
     }
 
   switch (ID) {