Reject struct vardecls with modifiers.

These aren't allowed in GLSL, and typically don't make sense.

Change-Id: I0afca0df638590466922a809e91ef0be35b13ca8
Bug: skia:10765
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/324816
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>

gn/sksl_tests.gni

@@ -99,6 +99,7 @@ sksl_error_tests = [
   "$_tests/sksl/errors/InvalidAssignment.sksl",
   "$_tests/sksl/errors/InvalidOutParams.sksl",
   "$_tests/sksl/errors/InvalidUnary.sksl",
+  "$_tests/sksl/errors/ModifiersInStruct.sksl",
   "$_tests/sksl/errors/OpenArray.sksl",
   "$_tests/sksl/errors/ReturnDifferentType.sksl",
   "$_tests/sksl/errors/ReturnFromVoid.sksl",

src/sksl/SkSLParser.cpp

@@ -503,9 +503,18 @@ ASTNode::ID Parser::structDeclaration() {
             return ASTNode::ID::Invalid();
         }
         ASTNode& declsNode = getNode(decls);
+        Modifiers modifiers = declsNode.begin()->getModifiers();
+        if (modifiers.fFlags != Modifiers::kNo_Flag) {
+            String desc = modifiers.description();
+            desc.pop_back();  // remove trailing space
+            this->error(declsNode.fOffset,
+                        "modifier '" + desc + "' is not permitted on a struct field");
+        }
+
         const Symbol* symbol = fSymbols[(declsNode.begin() + 1)->getTypeData().fName];
-        SkASSERT(symbol && symbol->kind() == Symbol::Kind::kType);
-        const Type* type = (const Type*) symbol;
+        SkASSERT(symbol);
+        const Type* type = &symbol->as<Type>();
+
         for (auto iter = declsNode.begin() + 2; iter != declsNode.end(); ++iter) {
             ASTNode& var = *iter;
             ASTNode::VarData vd = var.getVarData();
@@ -521,7 +530,8 @@ ASTNode::ID Parser::structDeclaration() {
                         std::make_unique<Type>(typeName, Type::TypeKind::kArray, *type,
                                                (int)columns));
             }
-            fields.push_back(Type::Field(declsNode.begin()->getModifiers(), vd.fName, type));
+
+            fields.push_back(Type::Field(modifiers, vd.fName, type));
             if (vd.fSizeCount ? (var.begin() + (vd.fSizeCount - 1))->fNext : var.fFirstChild) {
                 this->error(declsNode.fOffset, "initializers are not permitted on struct fields");
             }

tests/sksl/errors/ModifiersInStruct.sksl

@@ -0,0 +1,7 @@
+struct S {
+    const float a;
+    uniform int b;
+    flat half4 c;
+    noperspective float4 d;
+    inout volatile restrict varying buffer coherent bool e;
+};

tests/sksl/errors/golden/ModifiersInStruct.glsl

@@ -0,0 +1,8 @@
+### Compilation failed:
+
+error: 1: modifier 'const' is not permitted on a struct field
+error: 1: modifier 'uniform' is not permitted on a struct field
+error: 1: modifier 'flat' is not permitted on a struct field
+error: 1: modifier 'noperspective' is not permitted on a struct field
+error: 1: modifier 'coherent volatile restrict buffer varying inout' is not permitted on a struct field
+5 errors