tint: Add ast::Identifier

An identifier node that is not an expression.

Will be used by:
* CallExpression
* DiagnosticControl
* IdentifierExpression
* MemberAccessorExpression
* TypeName

Bug: tint:1257
Bug: tint:1810
Change-Id: I1de719d8c570992fed08789c35ca6c4409789520
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/118340
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: James Price <jrprice@google.com>

src/tint/BUILD.gn

@@ -278,6 +278,7 @@ libtint_source_set("libtint_syntax_tree_src") {
     "ast/group_attribute.h",
     "ast/i32.h",
     "ast/id_attribute.h",
+    "ast/identifier.h",
     "ast/identifier_expression.h",
     "ast/if_statement.h",
     "ast/increment_decrement_statement.h",
@@ -623,6 +624,8 @@ libtint_source_set("libtint_ast_src") {
     "ast/i32.h",
     "ast/id_attribute.cc",
     "ast/id_attribute.h",
+    "ast/identifier.cc",
+    "ast/identifier.h",
     "ast/identifier_expression.cc",
     "ast/identifier_expression.h",
     "ast/if_statement.cc",
@@ -1328,6 +1331,7 @@ if (tint_build_unittests) {
       "ast/i32_test.cc",
       "ast/id_attribute_test.cc",
       "ast/identifier_expression_test.cc",
+      "ast/identifier_test.cc",
       "ast/if_statement_test.cc",
       "ast/increment_decrement_statement_test.cc",
       "ast/index_accessor_expression_test.cc",

src/tint/CMakeLists.txt

@@ -156,6 +156,8 @@ list(APPEND TINT_LIB_SRCS
   ast/i32.h
   ast/id_attribute.cc
   ast/id_attribute.h
+  ast/identifier.cc
+  ast/identifier.h
   ast/identifier_expression.cc
   ast/identifier_expression.h
   ast/if_statement.cc
@@ -850,6 +852,7 @@ if(TINT_BUILD_TESTS)
     ast/group_attribute_test.cc
     ast/i32_test.cc
     ast/id_attribute_test.cc
+    ast/identifier_test.cc
     ast/identifier_expression_test.cc
     ast/if_statement_test.cc
     ast/increment_decrement_statement_test.cc

src/tint/ast/identifier.cc

@@ -0,0 +1,40 @@
+// Copyright 2023 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "src/tint/ast/identifier.h"
+
+#include "src/tint/program_builder.h"
+
+TINT_INSTANTIATE_TYPEINFO(tint::ast::Identifier);
+
+namespace tint::ast {
+
+Identifier::Identifier(ProgramID pid, NodeID nid, const Source& src, Symbol sym)
+    : Base(pid, nid, src), symbol(sym) {
+    TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(AST, symbol, program_id);
+    TINT_ASSERT(AST, symbol.IsValid());
+}
+
+Identifier::Identifier(Identifier&&) = default;
+
+Identifier::~Identifier() = default;
+
+const Identifier* Identifier::Clone(CloneContext* ctx) const {
+    // Clone arguments outside of create() call to have deterministic ordering
+    auto src = ctx->Clone(source);
+    auto sym = ctx->Clone(symbol);
+    return ctx->dst->create<Identifier>(src, sym);
+}
+
+}  // namespace tint::ast

src/tint/ast/identifier.h

@@ -0,0 +1,47 @@
+// Copyright 2023 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_TINT_AST_IDENTIFIER_H_
+#define SRC_TINT_AST_IDENTIFIER_H_
+
+#include "src/tint/ast/node.h"
+
+namespace tint::ast {
+
+/// An identifier
+class Identifier final : public Castable<Identifier, ast::Node> {
+  public:
+    /// Constructor
+    /// @param pid the identifier of the program that owns this node
+    /// @param nid the unique node identifier
+    /// @param src the source of this node
+    /// @param sym the symbol for the identifier
+    Identifier(ProgramID pid, NodeID nid, const Source& src, Symbol sym);
+    /// Move constructor
+    Identifier(Identifier&&);
+    ~Identifier() override;
+
+    /// Clones this node and all transitive child nodes using the `CloneContext`
+    /// `ctx`.
+    /// @param ctx the clone context
+    /// @return the newly cloned node
+    const Identifier* Clone(CloneContext* ctx) const override;
+
+    /// The symbol for the identifier
+    const Symbol symbol;
+};
+
+}  // namespace tint::ast
+
+#endif  // SRC_TINT_AST_IDENTIFIER_H_

src/tint/ast/identifier_test.cc

@@ -0,0 +1,62 @@
+// Copyright 2023 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "gtest/gtest-spi.h"
+#include "src/tint/ast/test_helper.h"
+
+namespace tint::ast {
+namespace {
+
+using IdentifierTest = TestHelper;
+
+TEST_F(IdentifierTest, Creation) {
+    auto* i = Ident("ident");
+    EXPECT_EQ(i->symbol, Symbol(1, ID()));
+}
+
+TEST_F(IdentifierTest, Creation_WithSource) {
+    auto* i = Ident(Source{{20, 2}}, "ident");
+    EXPECT_EQ(i->symbol, Symbol(1, ID()));
+
+    auto src = i->source;
+    EXPECT_EQ(src.range.begin.line, 20u);
+    EXPECT_EQ(src.range.begin.column, 2u);
+}
+
+TEST_F(IdentifierTest, IsIdentifier) {
+    auto* i = Ident("ident");
+    EXPECT_TRUE(i->Is<Identifier>());
+}
+
+TEST_F(IdentifierTest, Assert_InvalidSymbol) {
+    EXPECT_FATAL_FAILURE(
+        {
+            ProgramBuilder b;
+            b.Ident("");
+        },
+        "internal compiler error");
+}
+
+TEST_F(IdentifierTest, Assert_DifferentProgramID_Symbol) {
+    EXPECT_FATAL_FAILURE(
+        {
+            ProgramBuilder b1;
+            ProgramBuilder b2;
+            b1.Ident(b2.Sym("b2"));
+        },
+        "internal compiler error");
+}
+
+}  // namespace
+}  // namespace tint::ast

src/tint/program_builder.h

@@ -54,6 +54,7 @@
 #include "src/tint/ast/for_loop_statement.h"
 #include "src/tint/ast/i32.h"
 #include "src/tint/ast/id_attribute.h"
+#include "src/tint/ast/identifier.h"
 #include "src/tint/ast/if_statement.h"
 #include "src/tint/ast/increment_decrement_statement.h"
 #include "src/tint/ast/index_accessor_expression.h"
@@ -1147,6 +1148,21 @@ class ProgramBuilder {
     /// @return `sym`
     Symbol Sym(Symbol sym) { return sym; }
 
+    /// @param source the source information
+    /// @param identifier the identifier symbol
+    /// @return an ast::Identifier with the given symbol
+    template <typename IDENTIFIER>
+    const ast::Identifier* Ident(const Source& source, IDENTIFIER&& identifier) {
+        return create<ast::Identifier>(source, Sym(std::forward<IDENTIFIER>(identifier)));
+    }
+
+    /// @param identifier the identifier symbol
+    /// @return an ast::Identifier with the given symbol
+    template <typename IDENTIFIER>
+    const ast::Identifier* Ident(IDENTIFIER&& identifier) {
+        return create<ast::Identifier>(Sym(std::forward<IDENTIFIER>(identifier)));
+    }
+
     /// @param expr the expression
     /// @return expr
     template <typename T>