1 /* Interface to C preprocessor macro tables for GDB. 2 Copyright (C) 2002, 2007, 2008, 2009 Free Software Foundation, Inc. 3 Contributed by Red Hat, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #ifndef MACROTAB_H 21 #define MACROTAB_H 22 23 struct obstack; 24 struct bcache; 25 26 /* How do we represent a source location? I mean, how should we 27 represent them within GDB; the user wants to use all sorts of 28 ambiguous abbreviations, like "break 32" and "break foo.c:32" 29 ("foo.c" may have been #included into several compilation units), 30 but what do we disambiguate those things to? 31 32 - Answer 1: "Filename and line number." (Or column number, if 33 you're picky.) That's not quite good enough. For example, the 34 same source file can be #included into several different 35 compilation units --- which #inclusion do you mean? 36 37 - Answer 2: "Compilation unit, filename, and line number." This is 38 a pretty good answer; GDB's `struct symtab_and_line' basically 39 embodies this representation. But it's still ambiguous; what if a 40 given compilation unit #includes the same file twice --- how can I 41 set a breakpoint on line 12 of the fifth #inclusion of "foo.c"? 42 43 - Answer 3: "Compilation unit, chain of #inclusions, and line 44 number." This is analogous to the way GCC reports errors in 45 #include files: 46 47 $ gcc -c base.c 48 In file included from header2.h:8, 49 from header1.h:3, 50 from base.c:5: 51 header3.h:1: parse error before ')' token 52 $ 53 54 GCC tells you exactly what path of #inclusions led you to the 55 problem. It gives you complete information, in a way that the 56 following would not: 57 58 $ gcc -c base.c 59 header3.h:1: parse error before ')' token 60 $ 61 62 Converting all of GDB to use this is a big task, and I'm not really 63 suggesting it should be a priority. But this module's whole 64 purpose is to maintain structures describing the macro expansion 65 process, so I think it's appropriate for us to take a little care 66 to do that in a complete fashion. 67 68 In this interface, the first line of a file is numbered 1, not 0. 69 This is the same convention the rest of GDB uses. */ 70 71 72 /* A table of all the macro definitions for a given compilation unit. */ 73 struct macro_table; 74 75 /* The definition of a single macro. */ 76 struct macro_definition; 77 78 /* A source file that participated in a compilation unit --- either a 79 main file, or an #included file. If a file is #included more than 80 once, the presence of the `included_from' and `included_at_line' 81 members means that we need to make one instance of this structure 82 for each #inclusion. Taken as a group, these structures form a 83 tree mapping the #inclusions that contributed to the compilation 84 unit, with the main source file as its root. 85 86 Beware --- not every source file mentioned in a compilation unit's 87 symtab structures will appear in the #inclusion tree! As of Oct 88 2002, GCC does record the effect of #line directives in the source 89 line info, but not in macro info. This means that GDB's symtabs 90 (built from the former, among other things) may mention filenames 91 that the #inclusion tree (built from the latter) doesn't have any 92 record of. See macroscope.c:sal_macro_scope for how to accomodate 93 this. 94 95 It's worth noting that libcpp has a simpler way of representing all 96 this, which we should consider switching to. It might even be 97 suitable for ordinary non-macro line number info. 98 99 Suppose you take your main source file, and after each line 100 containing an #include directive you insert the text of the 101 #included file. The result is a big file that pretty much 102 corresponds to the full text the compiler's going to see. There's 103 a one-to-one correspondence between lines in the big file and 104 per-inclusion lines in the source files. (Obviously, #include 105 directives that are #if'd out don't count. And you'll need to 106 append a newline to any file that doesn't end in one, to avoid 107 splicing the last #included line with the next line of the 108 #including file.) 109 110 Libcpp calls line numbers in this big imaginary file "logical line 111 numbers", and has a data structure called a "line map" that can map 112 logical line numbers onto actual source filenames and line numbers, 113 and also tell you the chain of #inclusions responsible for any 114 particular logical line number. Basically, this means you can pass 115 around a single line number and some kind of "compilation unit" 116 object and you get nice, unambiguous source code locations that 117 distinguish between multiple #inclusions of the same file, etc. 118 119 Pretty neat, huh? */ 120 121 struct macro_source_file 122 { 123 124 /* The macro table for the compilation unit this source location is 125 a part of. */ 126 struct macro_table *table; 127 128 /* A source file --- possibly a header file. */ 129 const char *filename; 130 131 /* The location we were #included from, or zero if we are the 132 compilation unit's main source file. */ 133 struct macro_source_file *included_by; 134 135 /* If `included_from' is non-zero, the line number in that source 136 file at which we were included. */ 137 int included_at_line; 138 139 /* Head of a linked list of the source files #included by this file; 140 our children in the #inclusion tree. This list is sorted by its 141 elements' `included_at_line' values, which are unique. (The 142 macro splay tree's ordering function needs this property.) */ 143 struct macro_source_file *includes; 144 145 /* The next file #included by our `included_from' file; our sibling 146 in the #inclusion tree. */ 147 struct macro_source_file *next_included; 148 }; 149 150 151 /* Create a new, empty macro table. Allocate it in OBSTACK, or use 152 xmalloc if OBSTACK is zero. Use BCACHE to store all macro names, 153 arguments, definitions, and anything else that might be the same 154 amongst compilation units in an executable file; if BCACHE is zero, 155 don't cache these things. 156 157 Note that, if either OBSTACK or BCACHE are non-zero, then removing 158 information from the table may leak memory. Neither obstacks nor 159 bcaches really allow you to remove information, so although we can 160 update the data structure to record the change, we can't free the 161 old data. At the moment, since we only provide obstacks and 162 bcaches for macro tables for symtabs, this isn't a problem; only 163 odd debugging information makes a definition and then deletes it at 164 the same source location (although 'gcc -DFOO -UFOO -DFOO=2' does 165 do that in GCC 4.1.2.). */ 166 struct macro_table *new_macro_table (struct obstack *obstack, 167 struct bcache *bcache); 168 169 170 /* Free TABLE, and any macro definitions, source file structures, 171 etc. it owns. This will raise an internal error if TABLE was 172 allocated on an obstack, or if it uses a bcache. */ 173 void free_macro_table (struct macro_table *table); 174 175 176 /* Set FILENAME as the main source file of TABLE. Return a source 177 file structure describing that file; if we record the #definition 178 of macros, or the #inclusion of other files into FILENAME, we'll 179 use that source file structure to indicate the context. 180 181 The "main source file" is the one that was given to the compiler; 182 all other source files that contributed to the compilation unit are 183 #included, directly or indirectly, from this one. 184 185 The macro table makes its own copy of FILENAME; the caller is 186 responsible for freeing FILENAME when it is no longer needed. */ 187 struct macro_source_file *macro_set_main (struct macro_table *table, 188 const char *filename); 189 190 191 /* Return the main source file of the macro table TABLE. */ 192 struct macro_source_file *macro_main (struct macro_table *table); 193 194 /* Mark the macro table TABLE so that macros defined in this table can 195 be redefined without error. Note that it invalid to call this if 196 TABLE is allocated on an obstack. */ 197 void macro_allow_redefinitions (struct macro_table *table); 198 199 200 /* Record a #inclusion. 201 Record in SOURCE's macro table that, at line number LINE in SOURCE, 202 we #included the file INCLUDED. Return a source file structure we 203 can use for symbols #defined or files #included into that. If we've 204 already created a source file structure for this #inclusion, return 205 the same structure we created last time. 206 207 The first line of the source file has a line number of 1, not 0. 208 209 The macro table makes its own copy of INCLUDED; the caller is 210 responsible for freeing INCLUDED when it is no longer needed. */ 211 struct macro_source_file *macro_include (struct macro_source_file *source, 212 int line, 213 const char *included); 214 215 216 /* Find any source file structure for a file named NAME, either 217 included into SOURCE, or SOURCE itself. Return zero if we have 218 none. NAME is only the final portion of the filename, not the full 219 path. e.g., `stdio.h', not `/usr/include/stdio.h'. If NAME 220 appears more than once in the inclusion tree, return the 221 least-nested inclusion --- the one closest to the main source file. */ 222 struct macro_source_file *(macro_lookup_inclusion 223 (struct macro_source_file *source, 224 const char *name)); 225 226 227 /* Record an object-like #definition (i.e., one with no parameter list). 228 Record in SOURCE's macro table that, at line number LINE in SOURCE, 229 we #defined a preprocessor symbol named NAME, whose replacement 230 string is REPLACEMENT. This function makes copies of NAME and 231 REPLACEMENT; the caller is responsible for freeing them. */ 232 void macro_define_object (struct macro_source_file *source, int line, 233 const char *name, const char *replacement); 234 235 236 /* Record an function-like #definition (i.e., one with a parameter list). 237 238 Record in SOURCE's macro table that, at line number LINE in SOURCE, 239 we #defined a preprocessor symbol named NAME, with ARGC arguments 240 whose names are given in ARGV, whose replacement string is REPLACEMENT. If 241 the macro takes a variable number of arguments, then ARGC should be 242 one greater than the number of named arguments, and ARGV[ARGC-1] 243 should be the string "...". This function makes its own copies of 244 NAME, ARGV, and REPLACEMENT; the caller is responsible for freeing 245 them. */ 246 void macro_define_function (struct macro_source_file *source, int line, 247 const char *name, int argc, const char **argv, 248 const char *replacement); 249 250 251 /* Record an #undefinition. 252 Record in SOURCE's macro table that, at line number LINE in SOURCE, 253 we removed the definition for the preprocessor symbol named NAME. */ 254 void macro_undef (struct macro_source_file *source, int line, 255 const char *name); 256 257 /* Different kinds of macro definitions. */ 258 enum macro_kind 259 { 260 macro_object_like, 261 macro_function_like 262 }; 263 264 265 /* A preprocessor symbol definition. */ 266 struct macro_definition 267 { 268 /* The table this definition lives in. */ 269 struct macro_table *table; 270 271 /* What kind of macro it is. */ 272 ENUM_BITFIELD (macro_kind) kind : 1; 273 274 /* If `kind' is `macro_function_like', the number of arguments it 275 takes, and their names. The names, and the array of pointers to 276 them, are in the table's bcache, if it has one. */ 277 int argc : 31; 278 const char * const *argv; 279 280 /* The replacement string (body) of the macro. This is in the 281 table's bcache, if it has one. */ 282 const char *replacement; 283 }; 284 285 286 /* Return a pointer to the macro definition for NAME in scope at line 287 number LINE of SOURCE. If LINE is -1, return the definition in 288 effect at the end of the file. The macro table owns the structure; 289 the caller need not free it. Return zero if NAME is not #defined 290 at that point. */ 291 struct macro_definition *(macro_lookup_definition 292 (struct macro_source_file *source, 293 int line, const char *name)); 294 295 296 /* Return the source location of the definition for NAME in scope at 297 line number LINE of SOURCE. Set *DEFINITION_LINE to the line 298 number of the definition, and return a source file structure for 299 the file. Return zero if NAME has no definition in scope at that 300 point, and leave *DEFINITION_LINE unchanged. */ 301 struct macro_source_file *(macro_definition_location 302 (struct macro_source_file *source, 303 int line, 304 const char *name, 305 int *definition_line)); 306 307 /* Callback function when walking a macro table. NAME is the name of 308 the macro, and DEFINITION is the definition. USER_DATA is an 309 arbitrary pointer which is passed by the caller to macro_for_each 310 or macro_for_each_in_scope. */ 311 typedef void (*macro_callback_fn) (const char *name, 312 const struct macro_definition *definition, 313 void *user_data); 314 315 /* Call the function FN for each macro in the macro table TABLE. 316 USER_DATA is passed, untranslated, to FN. */ 317 void macro_for_each (struct macro_table *table, macro_callback_fn fn, 318 void *user_data); 319 320 /* Call the function FN for each macro that is visible in a given 321 scope. The scope is represented by FILE and LINE. USER_DATA is 322 passed, untranslated, to FN. */ 323 void macro_for_each_in_scope (struct macro_source_file *file, int line, 324 macro_callback_fn fn, 325 void *user_data); 326 327 328 #endif /* MACROTAB_H */ 329