Cleanup the AST code by removing unused parts and get rid of the...

src/flow-graph.h

-// Copyright 2010 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-//       copyright notice, this list of conditions and the following
-//       disclaimer in the documentation and/or other materials provided
-//       with the distribution.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#ifndef V8_FLOW_GRAPH_H_
-#define V8_FLOW_GRAPH_H_
-
-#include "v8.h"
-
-#include "data-flow.h"
-#include "zone.h"
-
-namespace v8 {
-namespace internal {
-
-// The nodes of a flow graph are basic blocks.  Basic blocks consist of
-// instructions represented as pointers to AST nodes in the order that they
-// would be visited by the code generator.  A block can have arbitrarily many
-// (even zero) predecessors and up to two successors.  Blocks with multiple
-// predecessors are "join nodes" and blocks with multiple successors are
-// "branch nodes".  A block can be both a branch and a join node.
-//
-// Flow graphs are in edge split form: a branch node is never the
-// predecessor of a merge node.  Empty basic blocks are inserted to maintain
-// edge split form.
-class BasicBlock: public ZoneObject {
- public:
-  // Construct a basic block with a given predecessor.  NULL indicates no
-  // predecessor or that the predecessor will be set later.
-  explicit BasicBlock(BasicBlock* predecessor)
-      : predecessors_(2),
-        instructions_(8),
-        left_successor_(NULL),
-        right_successor_(NULL),
-        mark_(false) {
-    if (predecessor != NULL) AddPredecessor(predecessor);
-  }
-
-  bool HasPredecessor() { return !predecessors_.is_empty(); }
-  bool HasSuccessor() { return left_successor_ != NULL; }
-
-  // Add a given basic block as a predecessor of this block.  This function
-  // also adds this block as a successor of the given block.
-  void AddPredecessor(BasicBlock* predecessor) {
-    ASSERT(predecessor != NULL);
-    predecessors_.Add(predecessor);
-    predecessor->AddSuccessor(this);
-  }
-
-  // Add an instruction to the end of this block.  The block must be "open"
-  // by not having a successor yet.
-  void AddInstruction(AstNode* instruction) {
-    ASSERT(!HasSuccessor() && instruction != NULL);
-    instructions_.Add(instruction);
-  }
-
-  // Perform a depth-first traversal of graph rooted at this node,
-  // accumulating pre- and postorder traversal orders.  Visited nodes are
-  // marked with mark.
-  void BuildTraversalOrder(ZoneList<BasicBlock*>* preorder,
-                           ZoneList<BasicBlock*>* postorder,
-                           bool mark);
-  bool GetMark() { return mark_; }
-
-#ifdef DEBUG
-  // In debug mode, blocks are numbered in reverse postorder to help with
-  // printing.
-  int number() { return number_; }
-  void set_number(int n) { number_ = n; }
-
-  // Print a basic block, given the number of the first instruction.
-  // Returns the next number after the number of the last instruction.
-  int PrintAsText(int instruction_number);
-#endif
-
- private:
-  // Add a given basic block as successor to this block.  This function does
-  // not add this block as a predecessor of the given block so as to avoid
-  // circularity.
-  void AddSuccessor(BasicBlock* successor) {
-    ASSERT(right_successor_ == NULL && successor != NULL);
-    if (HasSuccessor()) {
-      right_successor_ = successor;
-    } else {
-      left_successor_ = successor;
-    }
-  }
-
-  ZoneList<BasicBlock*> predecessors_;
-  ZoneList<AstNode*> instructions_;
-  BasicBlock* left_successor_;
-  BasicBlock* right_successor_;
-
-  // Support for graph traversal.  Before traversal, all nodes in the graph
-  // have the same mark (true or false).  Traversal marks already-visited
-  // nodes with the opposite mark.  After traversal, all nodes again have
-  // the same mark.  Traversal of the same graph is not reentrant.
-  bool mark_;
-
-#ifdef DEBUG
-  int number_;
-#endif
-
-  DISALLOW_COPY_AND_ASSIGN(BasicBlock);
-};
-
-
-// A flow graph has distinguished entry and exit blocks.  The entry block is
-// the only one with no predecessors and the exit block is the only one with
-// no successors.
-class FlowGraph: public ZoneObject {
- public:
-  FlowGraph(BasicBlock* entry, BasicBlock* exit)
-      : entry_(entry), exit_(exit), preorder_(8), postorder_(8) {
-  }
-
-  ZoneList<BasicBlock*>* preorder() { return &preorder_; }
-  ZoneList<BasicBlock*>* postorder() { return &postorder_; }
-
-#ifdef DEBUG
-  void PrintAsText(Handle<String> name);
-#endif
-
- private:
-  BasicBlock* entry_;
-  BasicBlock* exit_;
-  ZoneList<BasicBlock*> preorder_;
-  ZoneList<BasicBlock*> postorder_;
-};
-
-
-// The flow graph builder walks the AST adding reachable AST nodes to the
-// flow graph as instructions.  It remembers the entry and exit nodes of the
-// graph, and keeps a pointer to the current block being constructed.
-class FlowGraphBuilder: public AstVisitor {
- public:
-  FlowGraphBuilder() {}
-
-  FlowGraph* Build(FunctionLiteral* lit);
-
- private:
-  // AST node visit functions.
-#define DECLARE_VISIT(type) virtual void Visit##type(type* node);
-  AST_NODE_LIST(DECLARE_VISIT)
-#undef DECLARE_VISIT
-
-  BasicBlock* entry_;
-  BasicBlock* exit_;
-  BasicBlock* current_;
-
-  DISALLOW_COPY_AND_ASSIGN(FlowGraphBuilder);
-};
-
-
-} }  // namespace v8::internal
-
-#endif  // V8_FLOW_GRAPH_H_