[MLIR] Better message for FuncOp type mismatch

[stephenneuendorffer]

Summary

Previously the actual types were not shown, which makes the message
difficult to grok in the context of long lowering chains. Also, it
appears that there were no actual tests for this.

[jurahul]

Should we do the same for result types as well?

[stephenneuendorffer]

In D88318#2295924, @jurahul wrote:

Should we do the same for result types as well?

Probably. It looks like theres alot of overlap between std::call and spirv::call and probably others. I suspect that all the 'FunctionLike' checking should be factored out.

[jurahul]

Agreed. I was initially going to suggest CallOpInterface (for the operand type checking) to cover even more cases, but realized that for CallOpInterface does not guaranteed that operand and callee argument type will be same, so that's not the place. We can actually factor out a checker to check that the given 2 type ranges are identical (same number and same types) and use that for operand & result checks for CallOp and other places as well.

[stephenneuendorffer]

I'll land this. @jurahul are you able to look at the refactoring part?

mlir/lib/Dialect/StandardOps/IR/Ops.cpp

static LogicalResult verify(CallOp op) {
 
   // Verify that the operand and result types match the callee.
   auto fnType = fn.getType();
   if (fnType.getNumInputs() != op.getNumOperands())
     return op.emitOpError("incorrect number of operands for callee");
 
   for (unsigned i = 0, e = fnType.getNumInputs(); i != e; ++i)
     if (op.getOperand(i).getType() != fnType.getInput(i))
-      return op.emitOpError("operand type mismatch");
+      return op.emitOpError(
+                 "operand type mismatch: expected operand type ")
+             << fnType.getInput(i) << ", but provided "
+             << op.getOperand(i).getType() << " for operand number "
+             << i;
  
   if (fnType.getNumResults() != op.getNumResults())
     return op.emitOpError("incorrect number of results for callee");
 
   for (unsigned i = 0, e = fnType.getNumResults(); i != e; ++i)
     if (op.getResult(i).getType() != fnType.getResult(i))
       return op.emitOpError("result type mismatch");
 
   return success();

mlir/test/IR/operand.mlir

 
 // -----
 
 func @error_in_second_variadic_operand(%arg0: tensor<f32>, %arg1: f32) {
   // expected-error @+1 {{operand #3 must be tensor of any type}}
   "test.mixed_normal_variadic_operand"(%arg0, %arg0, %arg0, %arg1, %arg0) : (tensor<f32>, tensor<f32>, tensor<f32>, f32, tensor<f32>) -> ()
   return
 }
+
+// -----
+
+func @testfunc(%arg0: i32) {
+  return
+}
+func @invalid_call_operandtype() {
+  %0 = constant 0.0 : f32
+  // expected-error @+1 {{operand type mismatch: expected operand type 'i32', but provided 'f32' for operand number 0}}
+  call @testfunc(%0) : (f32) -> ()
+  return
+}