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switchnode.cc Go to the documentation of this file. // $Id: switchnode.cc,v 1.3 2003/08/07 23:13:13 pnav Exp $ // ---------------------------------------------------------------------- // // C-Breeze // C Compiler Framework // // Copyright (c) 2000 University of Texas at Austin // // Samuel Z. Guyer // Daniel A. Jimenez // Calvin Lin // // Permission is hereby granted, free of charge, to any person // obtaining a copy of this software and associated documentation // files (the "Software"), to deal in the Software without // restriction, including without limitation the rights to use, copy, // modify, merge, publish, distribute, sublicense, and/or sell copies // of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be // included in all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND // NONINFRINGEMENT. IN NO EVENT SHALL THE UNIVERSITY OF TEXAS AT // AUSTIN BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER // IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF // OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // THE SOFTWARE. // // We acknowledge the C-to-C Translator from MIT Laboratory for // Computer Science for inspiring parts of the C-Breeze design. // // ---------------------------------------------------------------------- #include "c_breeze.h" // -------------------------------------------------------------------- // Constructors // -------------------------------------------------------------------- switchNode::switchNode(exprNode * expr, stmtNode * stmt, const Coord coord) : selectionNode(Switch, expr, stmt, coord), _cases(), _has_default(false) {} // ------------------------------------------------------------ // Walker // ------------------------------------------------------------ void switchNode::visit(Visitor * the_visitor) { the_visitor->at_switch(this); } void switchNode::walk(Walker & the_walker) { Walker::Order ord = the_walker.order(); if (ord == Walker::Preorder || ord == Walker::Both) the_walker.at_switch(this, Walker::Preorder); if (the_walker.depth() == Walker::Subtree) { // -- Visit the children if (expr()) expr()->walk(the_walker); if (stmt()) stmt()->walk(the_walker); } if (ord == Walker::Postorder || ord == Walker::Both) the_walker.at_switch(this, Walker::Postorder); } // ------------------------------------------------------------ // Dataflow // ------------------------------------------------------------ void switchNode::dataflow(FlowVal * v, FlowProblem & fp) { if (fp.forward()) { fp.flow_switch(v, this, FlowProblem::Entry); if (expr()) if (fp.basicblocks()) { fp.flow_basicblock(v, expr(), FlowProblem::Entry); fp.flow_basicblock(v, expr(), FlowProblem::Exit); } else expr()->dataflow(v, fp); // -- at_top holds flow values needed at cases at_top()->meet_and_diff(v, fp); // -- If no default, then flow can fall through if (! has_default()) at_exit()->meet_and_diff(v, fp); // -- Dataflow the cases (pushes break values into at_exit) // Note: control does not flow directly into switch body v->to_top(); if (stmt()) stmt()->dataflow(v, fp); // -- Get the flow values collected from breaks v->meet(at_exit()); fp.flow_switch(v, this, FlowProblem::Exit); } else { fp.flow_switch(v, this, FlowProblem::Exit); // -- at_exit holds values needed by breaks at_exit()->meet_and_diff(v, fp); // -- If no default, then flow can fall through if (! has_default()) at_top()->meet_and_diff(at_exit(), fp); // -- Dataflow the cases (push values in to at_top) if (stmt()) stmt()->dataflow(v, fp); // -- Get the flow values collected from the cases // Note: control does not flow directly into switch body v->to_top(); v->meet(at_top()); if (expr()) if (fp.basicblocks()) { fp.flow_basicblock(v, expr(), FlowProblem::Exit); fp.flow_basicblock(v, expr(), FlowProblem::Entry); } else expr()->dataflow(v, fp); fp.flow_switch(v, this, FlowProblem::Entry); } } // ------------------------------------------------------------ // Output // ------------------------------------------------------------ void switchNode::output_stmt(output_context & ct, Node * parent) { ct << "switch " << '('; if (expr()) expr()->output(ct, this); ct << ')'; ct.space(); if (stmt()) stmt()->output(ct, this); else ct << ';'; } // ------------------------------------------------------------ // Changer // ------------------------------------------------------------ Node * switchNode::change(Changer & the_changer, bool redispatch) { Changer::Order ord = the_changer.order(); switchNode * the_switch = this; if ((ord == Changer::Preorder || ord == Changer::Both) && ! redispatch) the_switch = (switchNode *) the_changer.at_switch(the_switch, Changer::Preorder); if (the_switch) { if (the_switch != this) return the_switch->change(the_changer, true); exprNode * old_expr = the_switch->expr(); if (old_expr) { exprNode * new_expr = (exprNode *) old_expr->change(the_changer); if (old_expr != new_expr) { //if (the_changer.delete_old()) //delete old_expr; the_switch->expr(new_expr); } } blockNode * old_stmt = the_switch->stmt(); if (old_stmt) { blockNode * new_stmt = (blockNode *) old_stmt->change(the_changer); if (old_stmt != new_stmt) { //if (the_changer.delete_old()) //delete old_stmt; the_switch->stmt(new_stmt); } } } if ((ord == Changer::Postorder || ord == Changer::Both) && ! redispatch) the_switch = (switchNode *) the_changer.at_switch(the_switch, Changer::Postorder); return the_switch; } // ------------------------------------------------------------ // Destructor // ------------------------------------------------------------ switchNode::~switchNode() { }

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