[mlir][EmitC] Disallow string attributes as initial values (#75310)

Author: Simon Camphausen

mlir/lib/Dialect/EmitC/IR/EmitC.cpp

@@ -50,6 +50,32 @@ void mlir::emitc::buildTerminatedBody(OpBuilder &builder, Location loc) {
   builder.create<emitc::YieldOp>(loc);
 }
 
+/// Check that the type of the initial value is compatible with the operations
+/// result type.
+static LogicalResult verifyInitializationAttribute(Operation *op,
+                                                   Attribute value) {
+  assert(op->getNumResults() == 1 && "operation must have 1 result");
+
+  if (llvm::isa<emitc::OpaqueAttr>(value))
+    return success();
+
+  if (llvm::isa<StringAttr>(value))
+    return op->emitOpError()
+           << "string attributes are not supported, use #emitc.opaque instead";
+
+  Type resultType = op->getResult(0).getType();
+  Type attrType = cast<TypedAttr>(value).getType();
+
+  if (resultType != attrType)
+    return op->emitOpError()
+           << "requires attribute to either be an #emitc.opaque attribute or "
+              "it's type ("
+           << attrType << ") to match the op's result type (" << resultType
+           << ")";
+
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // AddOp
 //===----------------------------------------------------------------------===//
@@ -169,21 +195,14 @@ LogicalResult emitc::CallOpaqueOp::verify() {
 // ConstantOp
 //===----------------------------------------------------------------------===//
 
-/// The constant op requires that the attribute's type matches the return type.
 LogicalResult emitc::ConstantOp::verify() {
-  if (llvm::isa<emitc::OpaqueAttr>(getValueAttr()))
-    return success();
-
-  // Value must not be empty
-  StringAttr strAttr = llvm::dyn_cast<StringAttr>(getValueAttr());
-  if (strAttr && strAttr.empty())
-    return emitOpError() << "value must not be empty";
-
-  auto value = cast<TypedAttr>(getValueAttr());
-  Type type = getType();
-  if (!llvm::isa<NoneType>(value.getType()) && type != value.getType())
-    return emitOpError() << "requires attribute's type (" << value.getType()
-                         << ") to match op's return type (" << type << ")";
+  Attribute value = getValueAttr();
+  if (failed(verifyInitializationAttribute(getOperation(), value)))
+    return failure();
+  if (auto opaqueValue = llvm::dyn_cast<emitc::OpaqueAttr>(value)) {
+    if (opaqueValue.getValue().empty())
+      return emitOpError() << "value must not be empty";
+  }
   return success();
 }
 
@@ -561,17 +580,8 @@ LogicalResult SubOp::verify() {
 // VariableOp
 //===----------------------------------------------------------------------===//
 
-/// The variable op requires that the attribute's type matches the return type.
 LogicalResult emitc::VariableOp::verify() {
-  if (llvm::isa<emitc::OpaqueAttr>(getValueAttr()))
-    return success();
-
-  auto value = cast<TypedAttr>(getValueAttr());
-  Type type = getType();
-  if (!llvm::isa<NoneType>(value.getType()) && type != value.getType())
-    return emitOpError() << "requires attribute's type (" << value.getType()
-                         << ") to match op's return type (" << type << ")";
-  return success();
+  return verifyInitializationAttribute(getOperation(), getValueAttr());
 }
 
 //===----------------------------------------------------------------------===//

mlir/test/Dialect/EmitC/invalid_ops.mlir

@@ -1,24 +1,32 @@
 // RUN: mlir-opt %s -split-input-file -verify-diagnostics
 
+func.func @const_attribute_str() {
+    // expected-error @+1 {{'emitc.constant' op string attributes are not supported, use #emitc.opaque instead}}                 
+    %c0 = "emitc.constant"(){value = "NULL"} : () -> !emitc.ptr<i32>
+    return
+}
+
+// -----
+
 func.func @const_attribute_return_type_1() {
-    // expected-error @+1 {{'emitc.constant' op requires attribute's type ('i64') to match op's return type ('i32')}}
+    // expected-error @+1 {{'emitc.constant' op requires attribute to either be an #emitc.opaque attribute or it's type ('i64') to match the op's result type ('i32')}}
     %c0 = "emitc.constant"(){value = 42: i64} : () -> i32
     return
 }
 
 // -----
 
 func.func @const_attribute_return_type_2() {
-    // expected-error @+1 {{'emitc.constant' op requires attribute's type ('!emitc.opaque<"char">') to match op's return type ('!emitc.opaque<"mychar">')}}
-    %c0 = "emitc.constant"(){value = "CHAR_MIN" : !emitc.opaque<"char">} : () -> !emitc.opaque<"mychar">
+    // expected-error @+1 {{'emitc.constant' op attribute 'value' failed to satisfy constraint: An opaque attribute or TypedAttr instance}}
+    %c0 = "emitc.constant"(){value = unit} : () -> i32
     return
 }
 
 // -----
 
 func.func @empty_constant() {
     // expected-error @+1 {{'emitc.constant' op value must not be empty}}
-    %c0 = "emitc.constant"(){value = ""} : () -> i32
+    %c0 = "emitc.constant"(){value = #emitc.opaque<"">} : () -> i32
     return
 }
 
@@ -98,16 +106,16 @@ func.func @illegal_operand() {
 // -----
 
 func.func @var_attribute_return_type_1() {
-    // expected-error @+1 {{'emitc.variable' op requires attribute's type ('i64') to match op's return type ('i32')}}
+    // expected-error @+1 {{'emitc.variable' op requires attribute to either be an #emitc.opaque attribute or it's type ('i64') to match the op's result type ('i32')}}
     %c0 = "emitc.variable"(){value = 42: i64} : () -> i32
     return
 }
 
 // -----
 
 func.func @var_attribute_return_type_2() {
-    // expected-error @+1 {{'emitc.variable' op requires attribute's type ('!emitc.ptr<i64>') to match op's return type ('!emitc.ptr<i32>')}}
-    %c0 = "emitc.variable"(){value = "nullptr" : !emitc.ptr<i64>} : () -> !emitc.ptr<i32>
+    // expected-error @+1 {{'emitc.variable' op attribute 'value' failed to satisfy constraint: An opaque attribute or TypedAttr instance}}
+    %c0 = "emitc.variable"(){value = unit} : () -> i32
     return
 }
 

mlir/test/Target/Cpp/const.mlir

@@ -2,7 +2,7 @@
 // RUN: mlir-translate -mlir-to-cpp -declare-variables-at-top %s | FileCheck %s -check-prefix=CPP-DECLTOP
 
 func.func @emitc_constant() {
-  %c0 = "emitc.constant"(){value = #emitc.opaque<"">} : () -> i32
+  %c0 = "emitc.constant"(){value = #emitc.opaque<"INT_MAX">} : () -> i32
   %c1 = "emitc.constant"(){value = 42 : i32} : () -> i32
   %c2 = "emitc.constant"(){value = -1 : i32} : () -> i32
   %c3 = "emitc.constant"(){value = -1 : si8} : () -> si8
@@ -11,7 +11,7 @@ func.func @emitc_constant() {
   return
 }
 // CPP-DEFAULT: void emitc_constant() {
-// CPP-DEFAULT-NEXT: int32_t [[V0:[^ ]*]];
+// CPP-DEFAULT-NEXT: int32_t [[V0:[^ ]*]] = INT_MAX;
 // CPP-DEFAULT-NEXT: int32_t [[V1:[^ ]*]] = 42;
 // CPP-DEFAULT-NEXT: int32_t [[V2:[^ ]*]] = -1;
 // CPP-DEFAULT-NEXT: int8_t [[V3:[^ ]*]] = -1;
@@ -25,7 +25,7 @@ func.func @emitc_constant() {
 // CPP-DECLTOP-NEXT: int8_t [[V3:[^ ]*]];
 // CPP-DECLTOP-NEXT: uint8_t [[V4:[^ ]*]];
 // CPP-DECLTOP-NEXT: char [[V5:[^ ]*]];
-// CPP-DECLTOP-NEXT: ;
+// CPP-DECLTOP-NEXT: [[V0]] = INT_MAX;
 // CPP-DECLTOP-NEXT: [[V1]] = 42;
 // CPP-DECLTOP-NEXT: [[V2]] = -1;
 // CPP-DECLTOP-NEXT: [[V3]] = -1;