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goto_label_walker.cc
Go to the documentation of this file.00001 // $Id: goto_label_walker.cc,v 1.4 2003/08/07 23:13:44 pnav Exp $ 00002 // ---------------------------------------------------------------------- 00003 // 00004 // C-Breeze 00005 // C Compiler Framework 00006 // 00007 // Copyright (c) 2000 University of Texas at Austin 00008 // 00009 // Samuel Z. Guyer 00010 // Daniel A. Jimenez 00011 // Calvin Lin 00012 // 00013 // Permission is hereby granted, free of charge, to any person 00014 // obtaining a copy of this software and associated documentation 00015 // files (the "Software"), to deal in the Software without 00016 // restriction, including without limitation the rights to use, copy, 00017 // modify, merge, publish, distribute, sublicense, and/or sell copies 00018 // of the Software, and to permit persons to whom the Software is 00019 // furnished to do so, subject to the following conditions: 00020 // 00021 // The above copyright notice and this permission notice shall be 00022 // included in all copies or substantial portions of the Software. 00023 // 00024 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 00025 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 00026 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 00027 // NONINFRINGEMENT. IN NO EVENT SHALL THE UNIVERSITY OF TEXAS AT 00028 // AUSTIN BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 00029 // IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF 00030 // OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 00031 // THE SOFTWARE. 00032 // 00033 // We acknowledge the C-to-C Translator from MIT Laboratory for 00034 // Computer Science for inspiring parts of the C-Breeze design. 00035 // 00036 // ---------------------------------------------------------------------- 00037 00038 #include "c_breeze.h" 00039 #include "goto_label_walker.h" 00040 00041 // ------------------------------------------------------------ 00042 // Entry points 00043 // ------------------------------------------------------------ 00044 00045 void goto_label_walker::fixup(procNode * proc) 00046 { 00047 goto_label_walker g; 00048 00049 // -- Two passes: the first collects the labels... 00050 00051 proc->walk(g); 00052 g._have_labels = true; 00053 00054 // -- The second fixes the gotos... 00055 00056 proc->walk(g); 00057 00058 // -- Report any unused symbols... 00059 00060 g._labels.reset(); 00061 } 00062 00063 void goto_label_walker::fixup(unitNode * prog) 00064 { 00065 def_list & ds = prog->defs(); 00066 00067 for (def_list_p p = ds.begin(); p != ds.end(); ++p) 00068 if ((*p)->typ() == Proc) 00069 fixup((procNode *)(*p)); 00070 } 00071 00072 // ------------------------------------------------------------ 00073 // Handle labels 00074 // On the first pass, at a label we insert the label in the 00075 // table. 00076 // ------------------------------------------------------------ 00077 00078 void goto_label_walker::at_label(labelNode * the_label, Order ord) 00079 { 00080 if (! _have_labels) { 00081 00082 // -- Remove any old goto references... 00083 00084 the_label->references().clear(); 00085 00086 // -- Insert the label into the symbol table... 00087 00088 labelNode * orig = _labels.insert(the_label->name(), the_label); 00089 00090 if (orig) { 00091 CBZ::SyntaxError(the_label->coord(), 00092 string("multiple definitions of label `") + 00093 the_label->name() + string("'")); 00094 cerr << "\tPrevious definition: " << orig->coord() << endl; 00095 } 00096 } 00097 } 00098 00099 // ------------------------------------------------------------ 00100 // Handle gotos 00101 // On the second pass, we lookup the gotos and point them at 00102 // their labels. 00103 // ------------------------------------------------------------ 00104 00105 void goto_label_walker::at_goto(gotoNode * the_goto, Order ord) 00106 { 00107 if (_have_labels) { 00108 00109 // -- Try to find a matching label 00110 00111 labelNode * the_label = _labels.lookup(the_goto->name()); 00112 00113 if (! the_label) 00114 CBZ::SyntaxError(the_goto->coord(), 00115 string("undefined label `") + 00116 the_goto->name() + string("'")); 00117 else { 00118 00119 // -- Set the label field and add this "goto" to it's references 00120 00121 the_goto->label(the_label); 00122 the_label->references().push_back(the_goto); 00123 the_label->references().sort(); 00124 the_label->references().unique(); 00125 } 00126 } 00127 }