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dismantle-flatten.cc Go to the documentation of this file. // $Id: dismantle-flatten.cc,v 1.13 2003/08/07 23:13:43 pnav Exp $ // ---------------------------------------------------------------------- // // C-Breeze // C Compiler Framework // // Copyright (c) 2000 University of Texas at Austin // // Samuel Z. Guyer // Daniel A. Jimenez // Calvin Lin // Adam Brown // // 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. // // ---------------------------------------------------------------------- // // dismantle-flatten.cc // #include "c_breeze.h" #include "dismantle.h" #include <sstream> FlattenDismantle::FlattenDismantle(void): Changer(Both, Subtree, false), _new_body(NULL), _last_stmt(NULL), _vars() {} Node * FlattenDismantle::at_proc(procNode * the_proc, Order ord) { if ( ord == Preorder ) { _new_body = new blockNode(NULL, NULL); _last_stmt = NULL; assert(the_proc->decl()->type()->typ() == Func); decl_list & args = ((funcNode *) the_proc->decl()->type())->args(); for ( decl_list_p arg_decl = args.begin(); arg_decl != args.end(); arg_decl++ ) { _vars.insert((*arg_decl)->name()); } } else { // ord == Postorder // remove sections of code that are a label followed by a goto stmt_list_p next = _new_body->stmts().begin(); stmtNode *prev = NULL; while ( next != _new_body->stmts().end() ) { stmt_list_p curr = next; next++; if ( next != _new_body->stmts().end() && (*curr)->typ() == Label && (*next)->typ() == Goto ) { labelNode * the_label = (labelNode *) *curr; labelNode * new_label = ((gotoNode *) *next)->label(); goto_list_p next_goto = the_label->references().begin(); while ( next_goto != the_label->references().end() ) { gotoNode * curr_goto = *next_goto; next_goto++; curr_goto->label(new_label); } _new_body->stmts().erase(curr); // the Label curr = next; next++; if(prev && prev->typ() != Goto) { // keep the Goto. prev = *curr; } else { _new_body->stmts().erase(curr); // the Goto // prev remains unchanged. } } else prev = *curr; } the_proc->body(_new_body); } return the_proc; } Node * FlattenDismantle::at_decl(declNode * the_decl, Order ord) { if ( ord == Preorder ) { if ( the_decl->decl_location() == declNode::BLOCK ) { int next_num = 0; string base_name(the_decl->name()); bool changed_name = false; // ensure that we don't have another variable by this name in this proc while ( _vars.find(the_decl->name()) != _vars.end() ) { ostringstream ost; ost << base_name << next_num; the_decl->name(ost.str()); next_num++; changed_name = true; } if ( changed_name ) { // update all the idNodes that point to this decl for ( id_list_p p = the_decl->ref_list().begin(); p != the_decl->ref_list().end(); p++ ) { (*p)->name(the_decl->name()); } } _vars.insert(the_decl->name()); _new_body->decls().push_back(the_decl); } } return the_decl; } Node * FlattenDismantle::at_label(labelNode * the_label, Order ord) { // we only want to keep the label if some goto points to it if ( ord == Preorder && the_label->references().size() > 0 ) if ( _last_stmt && _last_stmt->typ() == Label ) { // if the last statment seen was also a label, just update all of the // gotoNode's that point to the_label to point to the last label goto_list_p next = the_label->references().begin(); while ( next != the_label->references().end() ) { gotoNode * curr = *next; next++; curr->label((labelNode *) _last_stmt); } } else { int next_num = 0; string base_name(the_label->name()); bool changed_name = false; // ensure that we don't have another label with this same name while ( _labels.find(the_label->name()) != _labels.end() ) { ostringstream ost; ost << base_name << next_num; the_label->name(ost.str()); next_num++; changed_name = true; } if (changed_name ) { // update all gotoNodes that point to this labelNode for ( goto_list_p p = the_label->references().begin(); p != the_label->references().end(); p++ ) { (*p)->name(the_label->name()); } } _labels.insert(the_label->name()); _new_body->stmts().push_back(the_label); _last_stmt = the_label; } return the_label; } Node * FlattenDismantle::at_threeAddr(threeAddrNode * the_3addr, Order ord) { if ( ord == Preorder ) { _new_body->stmts().push_back(the_3addr); _last_stmt = the_3addr; } return the_3addr; } // This also captures conditiongotoNodes. Node * FlattenDismantle::at_goto(gotoNode * the_goto, Order ord) { if ( ord == Preorder ) { // the second unconditional goto is unreachable, so remove it here if ( ! (_last_stmt && _last_stmt->typ() == Goto) ) { _new_body->stmts().push_back(the_goto); _last_stmt = the_goto; } } return the_goto; } Node * FlattenDismantle::at_return(returnNode * the_return, Order ord) { if ( ord == Preorder ) { _new_body->stmts().push_back(the_return); _last_stmt = the_return; } return the_return; } Node * FlattenDismantle::at_exprstmt(exprstmtNode * the_exprstmt, Order ord) { if ( ord == Preorder ) { if ( the_exprstmt->expr() ) { _new_body->stmts().push_back(the_exprstmt); _last_stmt = the_exprstmt; } } return the_exprstmt; }

Generated on August 27, 2003
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