[Mlir-commits] [mlir] [mlir] Fix conflict of user defined reserved functions with internal prototypes (PR #123378)

[Christian Ulmann]

================
@@ -48,53 +48,74 @@ static constexpr llvm::StringRef kMemRefCopy = "memrefCopy";
 LLVM::LLVMFuncOp mlir::LLVM::lookupOrCreateFn(Operation *moduleOp,
                                               StringRef name,
                                               ArrayRef<Type> paramTypes,
-                                              Type resultType, bool isVarArg) {
+                                              Type resultType, bool isVarArg,
+                                              bool isReserved) {
   assert(moduleOp->hasTrait<OpTrait::SymbolTable>() &&
          "expected SymbolTable operation");
   auto func = llvm::dyn_cast_or_null<LLVM::LLVMFuncOp>(
       SymbolTable::lookupSymbolIn(moduleOp, name));
-  if (func)
+  auto funcT = LLVMFunctionType::get(resultType, paramTypes, isVarArg);
+  // Assert the signature of the found function is same as expected
+  if (func) {
+    if (funcT != func.getFunctionType()) {
+      if (isReserved) {
+        func.emitError("redefinition of reserved function '" + name +
+                       "' of different type ")
+            .append(func.getFunctionType())
+            .append(" is prohibited");
+        exit(0);
+      } else {
+        func.emitError("redefinition of function '" + name +
+                       "' of different type ")
+            .append(funcT)
+            .append(" is prohibited");
+        exit(0);
+      }
+    }
     return func;
+  }
   OpBuilder b(moduleOp->getRegion(0));
   return b.create<LLVM::LLVMFuncOp>(
       moduleOp->getLoc(), name,
       LLVM::LLVMFunctionType::get(resultType, paramTypes, isVarArg));
 }
 
 LLVM::LLVMFuncOp mlir::LLVM::lookupOrCreatePrintI64Fn(Operation *moduleOp) {
-  return lookupOrCreateFn(moduleOp, kPrintI64,
-                          IntegerType::get(moduleOp->getContext(), 64),
-                          LLVM::LLVMVoidType::get(moduleOp->getContext()));
+  return lookupOrCreateFn(
+      moduleOp, kPrintI64, IntegerType::get(moduleOp->getContext(), 64),
+      LLVM::LLVMVoidType::get(moduleOp->getContext()), false, true);
----------------
Dinistro wrote:

```suggestion
      LLVM::LLVMVoidType::get(moduleOp->getContext()), /*isVarArg=*/false, /*isReserved=*/true);
```
If we keep this as is, the boolean parameters should be prefixed by their names to avoid confusion.

https://github.com/llvm/llvm-project/pull/123378