IR: Disallow complicated function-local metadata
Disallow complex types of function-local metadata. The only valid
function-local metadata is an `MDNode` whose sole argument is a
non-metadata function-local value.
Part of PR21532.
llvm-svn: 223564
diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index 3a7c293..45d61a1 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -185,43 +185,20 @@
return nullptr;
}
-#ifndef NDEBUG
-static const Function *assertLocalFunction(const MDNode *N) {
- if (!N->isFunctionLocal()) return nullptr;
-
- // FIXME: This does not handle cyclic function local metadata.
- const Function *F = nullptr, *NewF = nullptr;
- for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
- if (Value *V = N->getOperand(i)) {
- if (MDNode *MD = dyn_cast<MDNode>(V))
- NewF = assertLocalFunction(MD);
- else
- NewF = getFunctionForValue(V);
- }
- if (!F)
- F = NewF;
- else
- assert((NewF == nullptr || F == NewF) &&
- "inconsistent function-local metadata");
- }
- return F;
-}
-#endif
-
// getFunction - If this metadata is function-local and recursively has a
// function-local operand, return the first such operand's parent function.
// Otherwise, return null. getFunction() should not be used for performance-
// critical code because it recursively visits all the MDNode's operands.
const Function *MDNode::getFunction() const {
-#ifndef NDEBUG
- return assertLocalFunction(this);
-#else
- if (!isFunctionLocal()) return nullptr;
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
- if (const Function *F = getFunctionForValue(getOperand(i)))
- return F;
- return nullptr;
-#endif
+ if (!isFunctionLocal())
+ return nullptr;
+ assert(getNumOperands() == 1 &&
+ "Expected one operand for function-local metadata");
+ assert(getOperand(0) &&
+ "Expected non-null operand for function-local metadata");
+ assert(!getOperand(0)->getType()->isMetadataTy() &&
+ "Expected non-metadata as operand of function-local metadata");
+ return getFunctionForValue(getOperand(0));
}
/// \brief Check if the Value would require a function-local MDNode.
@@ -260,6 +237,14 @@
break;
}
+ if (isFunctionLocal) {
+ assert(Vals.size() == 1 &&
+ "Expected exactly one operand for function-local metadata");
+ assert(Vals[0] && "Expected non-null operand for function-local metadata");
+ assert(!Vals[0]->getType()->isMetadataTy() &&
+ "Expected non-metadata as operand of function-local metadata");
+ }
+
// Coallocate space for the node and Operands together, then placement new.
GenericMDNode *N =
new (Vals.size()) GenericMDNode(Context, Vals, isFunctionLocal);
@@ -323,6 +308,8 @@
// Handle this case by implicitly dropping the MDNode reference to null.
// Likewise if the MDNode is function-local but for a different function.
if (To && isFunctionLocalValue(To)) {
+ assert(!To->getType()->isMetadataTy() &&
+ "Expected non-metadata as operand of function-local metadata");
if (!isFunctionLocal())
To = nullptr;
else {
@@ -338,6 +325,14 @@
if (From == To)
return;
+ // If this MDValue was previously function-local but no longer is, clear
+ // its function-local flag.
+ if (isFunctionLocal() && !(To && isFunctionLocalValue(To))) {
+ assert(getNumOperands() == 1 &&
+ "Expected function-local metadata to have exactly one operand");
+ setValueSubclassData(getSubclassDataFromValue() & ~FunctionLocalBit);
+ }
+
// If this node is already not being uniqued (because one of the operands
// already went to null), then there is nothing else to do here.
if (isNotUniqued()) {
@@ -377,22 +372,6 @@
N->Hash = Key.Hash;
Store.insert(N);
-
- // If this MDValue was previously function-local but no longer is, clear
- // its function-local flag.
- if (isFunctionLocal() && !isFunctionLocalValue(To)) {
- bool isStillFunctionLocal = false;
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- Value *V = getOperand(i);
- if (!V) continue;
- if (isFunctionLocalValue(V)) {
- isStillFunctionLocal = true;
- break;
- }
- }
- if (!isStillFunctionLocal)
- setValueSubclassData(getSubclassDataFromValue() & ~FunctionLocalBit);
- }
}
MDNode *MDNode::concatenate(MDNode *A, MDNode *B) {