1 // Copyright 2020 The Tint Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #ifndef SRC_TRANSFORM_BOUND_ARRAY_ACCESSORS_TRANSFORM_H_
16 #define SRC_TRANSFORM_BOUND_ARRAY_ACCESSORS_TRANSFORM_H_
17 
18 #include <string>
19 
20 #include "src/ast/array_accessor_expression.h"
21 #include "src/ast/expression.h"
22 #include "src/ast/module.h"
23 #include "src/ast/statement.h"
24 #include "src/context.h"
25 #include "src/scope_stack.h"
26 #include "src/transform/transformer.h"
27 
28 namespace tint {
29 namespace transform {
30 
31 /// This transformer is responsible for clamping all array accesses to be within
32 /// the bounds of the array. Any access before the start of the array will clamp
33 /// to zero and any access past the end of the array will clamp to
34 /// (array length - 1).
35 class BoundArrayAccessorsTransform : public Transformer {
36  public:
37   /// Constructor
38   /// @param ctx the Tint context object
39   /// @param mod the module transform
40   explicit BoundArrayAccessorsTransform(Context* ctx, ast::Module* mod);
41   ~BoundArrayAccessorsTransform() override;
42 
43   /// @returns true if the transformation was successful
44   bool Run() override;
45 
46  private:
47   bool ProcessStatement(ast::Statement* stmt);
48   bool ProcessExpression(ast::Expression* expr);
49   bool ProcessArrayAccessor(ast::ArrayAccessorExpression* expr);
50   bool ProcessAccessExpression(ast::ArrayAccessorExpression* expr,
51                                uint32_t size);
52 
53   ScopeStack<ast::Variable*> scope_stack_;
54 };
55 
56 }  // namespace transform
57 }  // namespace tint
58 
59 #endif  // SRC_TRANSFORM_BOUND_ARRAY_ACCESSORS_TRANSFORM_H_
60