Remove sem::AccessControl

In preparation for implementing
https://github.com/gpuweb/gpuweb/issues/1604, this change removes the
sem::AccessControl node. Instead, the ast::AccessControl::Access enum is
now on the sem::StorageTexture class, as well as on sem::Variable. For
sem::Variable, the field is set when the variable's type is either a
storage buffer or a storage texture.

Bug: tint:802
Change-Id: Id479af36b401d067b015027923f4e715f5f69f25
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/51020
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>

src/ast/access_control.cc

@@ -37,6 +37,9 @@ AccessControl::~AccessControl() = default;
 std::string AccessControl::type_name() const {
   std::string name = "__access_control_";
   switch (access_) {
+    case ast::AccessControl::kInvalid:
+      name += "invalid";
+      break;
     case ast::AccessControl::kReadOnly:
       name += "read_only";
       break;
@@ -54,6 +57,9 @@ std::string AccessControl::FriendlyName(const SymbolTable& symbols) const {
   std::ostringstream out;
   out << "[[access(";
   switch (access_) {
+    case ast::AccessControl::kInvalid:
+      out << "invalid";
+      break;
     case ast::AccessControl::kReadOnly:
       out << "read";
       break;
@@ -77,6 +83,10 @@ AccessControl* AccessControl::Clone(CloneContext* ctx) const {
 
 std::ostream& operator<<(std::ostream& out, AccessControl::Access access) {
   switch (access) {
+    case ast::AccessControl::kInvalid: {
+      out << "invalid";
+      break;
+    }
     case ast::AccessControl::kReadOnly: {
       out << "read_only";
       break;

src/ast/access_control.h

@@ -28,8 +28,11 @@ class AccessControl : public Castable<AccessControl, Type> {
  public:
   /// The access control settings
   enum Access {
+    /// Invalid
+    // TODO(crbug.com/tint/805): Remove this.
+    kInvalid = -1,
     /// Read only
-    kReadOnly = 0,
+    kReadOnly,
     /// Write only
     kWriteOnly,
     /// Read write

src/ast/intrinsic_texture_helper_test.cc

@@ -14,7 +14,6 @@
 
 #include "src/ast/intrinsic_texture_helper_test.h"
 
-#include "src/sem/access_control_type.h"
 #include "src/sem/depth_texture_type.h"
 #include "src/sem/multisampled_texture_type.h"
 #include "src/sem/sampled_texture_type.h"
@@ -173,7 +172,7 @@ ast::Variable* TextureOverloadCase::buildTextureVariable(
 
     case ast::intrinsic::test::TextureKind::kStorage: {
       auto st = b->ty.storage_texture(texture_dimension, image_format);
-      auto ac = b->ty.access(access_control, st);
+      auto* ac = b->ty.access(access_control, st);
       return b->Global("texture", ac, ast::StorageClass::kNone, nullptr, decos);
     }
   }

src/ast/variable.cc

@@ -27,7 +27,7 @@ Variable::Variable(ProgramID program_id,
                    const Source& source,
                    const Symbol& sym,
                    StorageClass declared_storage_class,
-                   ast::Type* type,
+                   const ast::Type* type,
                    bool is_const,
                    Expression* constructor,
                    DecorationList decorations)

src/ast/variable.h

@@ -109,7 +109,7 @@ class Variable : public Castable<Variable, Node> {
            const Source& source,
            const Symbol& sym,
            StorageClass declared_storage_class,
-           ast::Type* type,
+           const ast::Type* type,
            bool is_const,
            Expression* constructor,
            DecorationList decorations);
@@ -122,7 +122,7 @@ class Variable : public Castable<Variable, Node> {
   const Symbol& symbol() const { return symbol_; }
 
   /// @returns the variable type
-  ast::Type* type() const { return type_; }
+  ast::Type* type() const { return const_cast<ast::Type*>(type_); }
 
   /// @returns the declared storage class
   StorageClass declared_storage_class() const {
@@ -177,7 +177,7 @@ class Variable : public Castable<Variable, Node> {
 
   Symbol const symbol_;
   // The value type if a const or formal paramter, and the store type if a var
-  ast::Type* const type_;
+  ast::Type const* const type_;
   bool const is_const_;
   Expression* const constructor_;
   DecorationList const decorations_;