Zachary Anderson
103881d01c
i.e. #ifndef VM_WHATEVER -> #ifndef RUNTIME_VM_WHATEVER This lets us remove a hack from the PRESUBMIT.py script that existed for reasons that are no longer valid, and sets us up to add some presubmit checks for the GN build. R=asiva@google.com, rmacnak@google.com Review URL: https://codereview.chromium.org/2450713004 .
81 lines
2.4 KiB
C++
81 lines
2.4 KiB
C++
// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef RUNTIME_VM_AST_TRANSFORMER_H_
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#define RUNTIME_VM_AST_TRANSFORMER_H_
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#include "platform/assert.h"
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#include "vm/ast.h"
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namespace dart {
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class Thread;
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// Translate an AstNode containing an expression (that itself contains one or
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// more awaits) into a sequential representation where subexpressions are
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// evaluated sequentially into intermediates. Those intermediates are stored
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// within a context.
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//
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// This allows a function to be suspended and resumed from within evaluating an
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// expression. The evaluation is split among a so-called preamble and the
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// evaluation of the resulting expression (which is only a single load).
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//
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// Example (minimalistic):
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//
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// var a = (await bar()) + foo();
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//
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// This translates to a premable similar to:
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//
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// var t_1, t_2, t_3, t_4; // All stored in a context.
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// t_1 = bar();
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// :result_param = t_1;
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// <continuation logic>
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// t_2 = :result_param;
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// t_3 = foo();
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// t_4 = t_2.operator+(t_3);
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//
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// and a resulting expression of a load of t_4.
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//
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class AwaitTransformer : public AstNodeVisitor {
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public:
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AwaitTransformer(SequenceNode* preamble, LocalScope* async_temp_scope);
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#define DECLARE_VISIT(BaseName) \
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virtual void Visit##BaseName##Node(BaseName##Node* node);
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FOR_EACH_NODE(DECLARE_VISIT)
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#undef DECLARE_VISIT
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AstNode* Transform(AstNode* expr);
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private:
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LocalVariable* EnsureCurrentTempVar();
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LocalVariable* AddNewTempVarToPreamble(AstNode* node,
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TokenPosition token_pos);
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LoadLocalNode* MakeName(AstNode* node);
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ArgumentListNode* TransformArguments(ArgumentListNode* node);
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AstNode* LazyTransform(const Token::Kind kind,
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AstNode* new_left,
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AstNode* right);
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LocalScope* ChainNewScope(LocalScope* parent);
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LocalVariable* GetVariableInScope(LocalScope* scope, const String& symbol);
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void NextTempVar() { temp_cnt_++; }
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Thread* thread() const { return thread_; }
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SequenceNode* preamble_;
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int32_t temp_cnt_;
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AstNode* result_;
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LocalScope* async_temp_scope_;
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Thread* thread_;
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DISALLOW_COPY_AND_ASSIGN(AwaitTransformer);
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};
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} // namespace dart
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#endif // RUNTIME_VM_AST_TRANSFORMER_H_
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