1 | /* Exception Handling interface routines. |
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2 | Copyright (C) 1996, 1997 Free Software Foundation, Inc. |
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3 | Contributed by Mike Stump <mrs@cygnus.com>. |
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4 | |
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5 | This file is part of GNU CC. |
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6 | |
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7 | GNU CC is free software; you can redistribute it and/or modify |
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8 | it under the terms of the GNU General Public License as published by |
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9 | the Free Software Foundation; either version 2, or (at your option) |
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10 | any later version. |
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11 | |
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12 | GNU CC is distributed in the hope that it will be useful, |
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13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | GNU General Public License for more details. |
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16 | |
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17 | You should have received a copy of the GNU General Public License |
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18 | along with GNU CC; see the file COPYING. If not, write to |
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19 | the Free Software Foundation, 59 Temple Place - Suite 330, |
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20 | Boston, MA 02111-1307, USA. */ |
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21 | |
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22 | |
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23 | #ifndef GET_CODE |
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24 | #define rtx int * |
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25 | #endif |
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26 | |
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27 | #ifdef TREE_CODE |
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28 | |
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29 | /* A stack of labels. CHAIN points to the next entry in the stack. */ |
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30 | |
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31 | struct label_node { |
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32 | union { |
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33 | rtx rlabel; |
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34 | tree tlabel; |
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35 | } u; |
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36 | struct label_node *chain; |
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37 | }; |
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38 | |
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39 | /* An eh_entry is used to describe one exception handling region. |
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40 | |
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41 | OUTER_CONTEXT is the label used for rethrowing into the outer context. |
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42 | |
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43 | EXCEPTION_HANDLER_LABEL is the label corresponding to the handler |
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44 | for this region. |
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45 | |
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46 | FINALIZATION is the tree codes for the handler, or is NULL_TREE if |
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47 | one hasn't been generated yet, or is integer_zero_node to mark the |
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48 | end of a group of try blocks. */ |
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49 | |
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50 | struct eh_entry { |
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51 | rtx outer_context; |
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52 | rtx exception_handler_label; |
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53 | |
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54 | tree finalization; |
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55 | }; |
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56 | |
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57 | /* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next |
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58 | entry in the list, or is NULL if this is the last entry. */ |
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59 | |
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60 | struct eh_node { |
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61 | struct eh_entry *entry; |
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62 | struct eh_node *chain; |
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63 | }; |
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64 | |
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65 | /* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is |
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66 | NULL if the stack is empty. */ |
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67 | |
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68 | struct eh_stack { |
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69 | struct eh_node *top; |
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70 | }; |
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71 | |
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72 | /* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the |
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73 | end (the latest entry). HEAD and TAIL are NULL if the queue is |
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74 | empty. */ |
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75 | |
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76 | struct eh_queue { |
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77 | struct eh_node *head; |
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78 | struct eh_node *tail; |
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79 | }; |
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80 | |
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81 | |
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82 | /* Start an exception handling region. All instructions emitted after |
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83 | this point are considered to be part of the region until |
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84 | expand_eh_region_end () is invoked. */ |
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85 | |
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86 | extern void expand_eh_region_start PROTO((void)); |
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87 | |
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88 | /* Just like expand_eh_region_start, except if a cleanup action is |
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89 | entered on the cleanup chain, the TREE_PURPOSE of the element put |
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90 | on the chain is DECL. DECL should be the associated VAR_DECL, if |
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91 | any, otherwise it should be NULL_TREE. */ |
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92 | |
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93 | extern void expand_eh_region_start_for_decl PROTO((tree)); |
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94 | |
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95 | /* Start an exception handling region for the given cleanup action. |
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96 | All instructions emitted after this point are considered to be part |
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97 | of the region until expand_eh_region_end () is invoked. CLEANUP is |
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98 | the cleanup action to perform. The return value is true if the |
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99 | exception region was optimized away. If that case, |
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100 | expand_eh_region_end does not need to be called for this cleanup, |
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101 | nor should it be. |
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102 | |
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103 | This routine notices one particular common case in C++ code |
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104 | generation, and optimizes it so as to not need the exception |
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105 | region. */ |
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106 | |
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107 | extern int expand_eh_region_start_tree PROTO((tree, tree)); |
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108 | |
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109 | /* End an exception handling region. The information about the region |
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110 | is found on the top of ehstack. |
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111 | |
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112 | HANDLER is either the cleanup for the exception region, or if we're |
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113 | marking the end of a try block, HANDLER is integer_zero_node. |
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114 | |
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115 | HANDLER will be transformed to rtl when expand_leftover_cleanups () |
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116 | is invoked. */ |
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117 | |
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118 | extern void expand_eh_region_end PROTO((tree)); |
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119 | |
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120 | /* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL |
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121 | should be set; the other must be NULL. */ |
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122 | |
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123 | extern void push_label_entry PROTO((struct label_node **labelstack, rtx rlabel, tree tlabel)); |
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124 | |
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125 | /* Pop the topmost entry from LABELSTACK and return its value as an |
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126 | rtx node. If LABELSTACK is empty, return NULL. */ |
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127 | |
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128 | extern rtx pop_label_entry PROTO((struct label_node **labelstack)); |
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129 | |
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130 | /* Return the topmost entry of LABELSTACK as a tree node, or return |
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131 | NULL_TREE if LABELSTACK is empty. */ |
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132 | |
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133 | extern tree top_label_entry PROTO((struct label_node **labelstack)); |
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134 | |
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135 | /* A set of insns for the catch clauses in the current function. They |
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136 | will be emitted at the end of the current function. */ |
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137 | |
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138 | extern rtx catch_clauses; |
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139 | |
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140 | #endif |
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141 | |
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142 | /* Toplevel initialization for EH. */ |
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143 | |
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144 | extern void init_eh PROTO((void)); |
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145 | |
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146 | /* Initialization for the per-function EH data. */ |
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147 | |
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148 | extern void init_eh_for_function PROTO((void)); |
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149 | |
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150 | /* Adds an EH table entry for EH entry number N. Called from |
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151 | final_scan_insn for NOTE_INSN_EH_REGION_BEG. */ |
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152 | |
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153 | extern void add_eh_table_entry PROTO((int n)); |
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154 | |
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155 | /* Returns a non-zero value if we need to output an exception table. */ |
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156 | |
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157 | extern int exception_table_p PROTO((void)); |
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158 | |
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159 | /* Outputs the exception table if we have one. */ |
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160 | |
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161 | extern void output_exception_table PROTO((void)); |
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162 | |
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163 | /* Given a return address in ADDR, determine the address we should use |
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164 | to find the corresponding EH region. */ |
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165 | |
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166 | extern rtx eh_outer_context PROTO((rtx addr)); |
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167 | |
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168 | /* Called at the start of a block of try statements for which there is |
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169 | a supplied catch handler. */ |
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170 | |
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171 | extern void expand_start_try_stmts PROTO((void)); |
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172 | |
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173 | /* Called at the start of a block of catch statements. It terminates the |
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174 | previous set of try statements. */ |
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175 | |
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176 | extern void expand_start_all_catch PROTO((void)); |
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177 | |
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178 | /* Called at the end of a block of catch statements. */ |
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179 | |
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180 | extern void expand_end_all_catch PROTO((void)); |
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181 | |
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182 | #ifdef TREE_CODE |
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183 | /* Create a new exception region and add the handler for the region |
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184 | onto a list. These regions will be ended (and their handlers |
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185 | emitted) when end_protect_partials is invoked. */ |
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186 | |
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187 | extern void add_partial_entry PROTO((tree handler)); |
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188 | #endif |
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189 | |
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190 | /* End all of the pending exception regions that have handlers added with |
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191 | push_protect_entry (). */ |
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192 | |
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193 | extern void end_protect_partials PROTO((void)); |
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194 | |
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195 | /* An internal throw with a direct CONTEXT we want to throw |
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196 | from. CONTEXT must be a label. */ |
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197 | |
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198 | extern void expand_internal_throw PROTO((rtx context)); |
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199 | |
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200 | /* Called from expand_exception_blocks and expand_end_catch_block to |
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201 | expand and pending handlers. */ |
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202 | |
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203 | extern void expand_leftover_cleanups PROTO((void)); |
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204 | |
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205 | /* If necessary, emit insns for the start of per-function unwinder for |
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206 | the current function. */ |
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207 | |
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208 | extern void emit_unwinder PROTO((void)); |
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209 | |
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210 | /* If necessary, emit insns for the end of the per-function unwinder |
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211 | for the current function. */ |
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212 | |
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213 | extern void end_eh_unwinder PROTO((void)); |
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214 | |
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215 | /* Builds a list of handler labels and puts them in the global |
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216 | variable exception_handler_labels. */ |
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217 | |
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218 | extern void find_exception_handler_labels PROTO((void)); |
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219 | |
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220 | /* Performs sanity checking on the check_exception_handler_labels |
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221 | list. */ |
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222 | |
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223 | extern void check_exception_handler_labels PROTO((void)); |
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224 | |
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225 | /* A stack used to keep track of the label used to resume normal program |
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226 | flow out of the current exception handler region. */ |
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227 | |
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228 | extern struct label_node *caught_return_label_stack; |
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229 | |
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230 | /* Keeps track of the label used as the context of a throw to rethrow an |
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231 | exception to the outer exception region. */ |
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232 | |
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233 | extern struct label_node *outer_context_label_stack; |
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234 | |
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235 | /* A random area used for purposes elsewhere. */ |
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236 | |
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237 | extern struct label_node *false_label_stack; |
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238 | |
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239 | /* A list of labels used for exception handlers. It is created by |
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240 | find_exception_handler_labels for the optimization passes. */ |
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241 | |
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242 | extern rtx exception_handler_labels; |
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243 | |
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244 | /* The rtx for the saved PC value. */ |
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245 | |
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246 | extern rtx eh_saved_pc_rtx; |
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247 | |
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248 | /* Performs optimizations for exception handling, such as removing |
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249 | unnecessary exception regions. Invoked from jump_optimize (). */ |
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250 | |
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251 | extern void exception_optimize PROTO((void)); |
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252 | |
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253 | /* Get the dynamic handler chain. */ |
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254 | extern rtx get_dynamic_handler_chain PROTO((void)); |
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255 | |
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256 | /* Get the dynamic cleanup chain. */ |
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257 | extern rtx get_dynamic_cleanup_chain PROTO((void)); |
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258 | |
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259 | /* Throw an exception. */ |
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260 | |
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261 | extern void emit_throw PROTO((void)); |
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262 | |
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263 | /* One to use setjmp/longjmp method of generating code. */ |
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264 | |
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265 | extern int exceptions_via_longjmp; |
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266 | |
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267 | /* One to enable asynchronous exception support. */ |
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268 | |
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269 | extern int asynchronous_exceptions; |
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270 | |
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271 | /* One to protect cleanup actions with a handler that calls |
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272 | __terminate, zero otherwise. */ |
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273 | |
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274 | extern int protect_cleanup_actions_with_terminate; |
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275 | |
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276 | #ifdef TREE_CODE |
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277 | extern tree protect_with_terminate PROTO((tree)); |
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278 | #endif |
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279 | |
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280 | /* Various hooks for the DWARF 2 __throw routine. */ |
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281 | |
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282 | void expand_builtin_unwind_init PROTO((void)); |
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283 | rtx expand_builtin_dwarf_fp_regnum PROTO((void)); |
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284 | rtx expand_builtin_eh_stub PROTO((void)); |
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285 | #ifdef TREE_CODE |
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286 | rtx expand_builtin_frob_return_addr PROTO((tree)); |
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287 | rtx expand_builtin_extract_return_addr PROTO((tree)); |
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288 | void expand_builtin_set_return_addr_reg PROTO((tree)); |
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289 | void expand_builtin_set_eh_regs PROTO((tree, tree)); |
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290 | rtx expand_builtin_dwarf_reg_size PROTO((tree, rtx)); |
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291 | #endif |
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