1 /* Convert symbols from GDB to GCC
3 Copyright (C) 2014-2018 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
22 #include "compile-internal.h"
23 #include "compile-c.h"
25 #include "parser-defs.h"
30 #include "exceptions.h"
32 #include "dwarf2loc.h"
36 /* Object of this type are stored in the compiler's symbol_err_map. */
42 const struct symbol *sym;
44 /* The error message to emit. This is malloc'd and owned by the
50 /* Hash function for struct symbol_error. */
53 hash_symbol_error (const void *a)
55 const struct symbol_error *se = (const struct symbol_error *) a;
57 return htab_hash_pointer (se->sym);
60 /* Equality function for struct symbol_error. */
63 eq_symbol_error (const void *a, const void *b)
65 const struct symbol_error *sea = (const struct symbol_error *) a;
66 const struct symbol_error *seb = (const struct symbol_error *) b;
68 return sea->sym == seb->sym;
71 /* Deletion function for struct symbol_error. */
74 del_symbol_error (void *a)
76 struct symbol_error *se = (struct symbol_error *) a;
82 /* Associate SYMBOL with some error text. */
85 insert_symbol_error (htab_t hash, const struct symbol *sym, const char *text)
87 struct symbol_error e;
91 slot = htab_find_slot (hash, &e, INSERT);
94 struct symbol_error *e = XNEW (struct symbol_error);
97 e->message = xstrdup (text);
102 /* Emit the error message corresponding to SYM, if one exists, and
103 arrange for it not to be emitted again. */
106 error_symbol_once (struct compile_c_instance *context,
107 const struct symbol *sym)
109 struct symbol_error search;
110 struct symbol_error *err;
112 if (context->symbol_err_map == NULL)
116 err = (struct symbol_error *) htab_find (context->symbol_err_map, &search);
117 if (err == NULL || err->message == NULL)
120 gdb::unique_xmalloc_ptr<char> message (err->message);
122 error (_("%s"), message.get ());
127 /* Compute the name of the pointer representing a local symbol's
130 static gdb::unique_xmalloc_ptr<char>
131 c_symbol_substitution_name (struct symbol *sym)
133 return gdb::unique_xmalloc_ptr<char>
134 (concat ("__", SYMBOL_NATURAL_NAME (sym), "_ptr", (char *) NULL));
137 /* Convert a given symbol, SYM, to the compiler's representation.
138 CONTEXT is the compiler instance. IS_GLOBAL is true if the
139 symbol came from the global scope. IS_LOCAL is true if the symbol
140 came from a local scope. (Note that the two are not strictly
141 inverses because the symbol might have come from the static
145 convert_one_symbol (struct compile_c_instance *context,
146 struct block_symbol sym,
151 const char *filename = symbol_symtab (sym.symbol)->filename;
152 unsigned short line = SYMBOL_LINE (sym.symbol);
154 error_symbol_once (context, sym.symbol);
156 if (SYMBOL_CLASS (sym.symbol) == LOC_LABEL)
159 sym_type = convert_type (context, SYMBOL_TYPE (sym.symbol));
161 if (SYMBOL_DOMAIN (sym.symbol) == STRUCT_DOMAIN)
163 /* Binding a tag, so we don't need to build a decl. */
164 context->c_plugin->tagbind (SYMBOL_NATURAL_NAME (sym.symbol),
165 sym_type, filename, line);
170 enum gcc_c_symbol_kind kind;
172 gdb::unique_xmalloc_ptr<char> symbol_name;
174 switch (SYMBOL_CLASS (sym.symbol))
177 kind = GCC_C_SYMBOL_TYPEDEF;
181 kind = GCC_C_SYMBOL_LABEL;
182 addr = SYMBOL_VALUE_ADDRESS (sym.symbol);
186 kind = GCC_C_SYMBOL_FUNCTION;
187 addr = BLOCK_START (SYMBOL_BLOCK_VALUE (sym.symbol));
188 if (is_global && TYPE_GNU_IFUNC (SYMBOL_TYPE (sym.symbol)))
189 addr = gnu_ifunc_resolve_addr (target_gdbarch (), addr);
193 if (TYPE_CODE (SYMBOL_TYPE (sym.symbol)) == TYPE_CODE_ENUM)
195 /* Already handled by convert_enum. */
198 context->c_plugin->build_constant
199 (sym_type, SYMBOL_NATURAL_NAME (sym.symbol),
200 SYMBOL_VALUE (sym.symbol),
204 case LOC_CONST_BYTES:
205 error (_("Unsupported LOC_CONST_BYTES for symbol \"%s\"."),
206 SYMBOL_PRINT_NAME (sym.symbol));
209 internal_error (__FILE__, __LINE__, _("LOC_UNDEF found for \"%s\"."),
210 SYMBOL_PRINT_NAME (sym.symbol));
212 case LOC_COMMON_BLOCK:
213 error (_("Fortran common block is unsupported for compilation "
214 "evaluaton of symbol \"%s\"."),
215 SYMBOL_PRINT_NAME (sym.symbol));
217 case LOC_OPTIMIZED_OUT:
218 error (_("Symbol \"%s\" cannot be used for compilation evaluation "
219 "as it is optimized out."),
220 SYMBOL_PRINT_NAME (sym.symbol));
225 /* Probably TLS here. */
226 warning (_("Symbol \"%s\" is thread-local and currently can only "
227 "be referenced from the current thread in "
229 SYMBOL_PRINT_NAME (sym.symbol));
232 /* 'symbol_name' cannot be used here as that one is used only for
233 local variables from compile_dwarf_expr_to_c.
234 Global variables can be accessed by GCC only by their address, not
238 struct frame_info *frame = NULL;
240 if (symbol_read_needs_frame (sym.symbol))
242 frame = get_selected_frame (NULL);
244 error (_("Symbol \"%s\" cannot be used because "
245 "there is no selected frame"),
246 SYMBOL_PRINT_NAME (sym.symbol));
249 val = read_var_value (sym.symbol, sym.block, frame);
250 if (VALUE_LVAL (val) != lval_memory)
251 error (_("Symbol \"%s\" cannot be used for compilation "
252 "evaluation as its address has not been found."),
253 SYMBOL_PRINT_NAME (sym.symbol));
255 kind = GCC_C_SYMBOL_VARIABLE;
256 addr = value_address (val);
264 case LOC_REGPARM_ADDR:
267 kind = GCC_C_SYMBOL_VARIABLE;
268 symbol_name = c_symbol_substitution_name (sym.symbol);
272 kind = GCC_C_SYMBOL_VARIABLE;
273 addr = SYMBOL_VALUE_ADDRESS (sym.symbol);
276 case LOC_FINAL_VALUE:
278 gdb_assert_not_reached ("Unreachable case in convert_one_symbol.");
282 /* Don't emit local variable decls for a raw expression. */
283 if (context->base.scope != COMPILE_I_RAW_SCOPE
284 || symbol_name == NULL)
286 decl = context->c_plugin->build_decl
287 (SYMBOL_NATURAL_NAME (sym.symbol),
290 symbol_name.get (), addr,
293 context->c_plugin->bind (decl, is_global);
298 /* Convert a full symbol to its gcc form. CONTEXT is the compiler to
299 use, IDENTIFIER is the name of the symbol, SYM is the symbol
300 itself, and DOMAIN is the domain which was searched. */
303 convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
304 struct block_symbol sym, domain_enum domain)
306 const struct block *static_block;
309 /* If we found a symbol and it is not in the static or global
310 scope, then we should first convert any static or global scope
311 symbol of the same name. This lets this unusual case work:
317 // At this spot, evaluate "extern int x; x"
321 static_block = block_static_block (sym.block);
322 /* STATIC_BLOCK is NULL if FOUND_BLOCK is the global block. */
323 is_local_symbol = (sym.block != static_block && static_block != NULL);
326 struct block_symbol global_sym;
328 global_sym = lookup_symbol (identifier, NULL, domain, NULL);
329 /* If the outer symbol is in the static block, we ignore it, as
330 it cannot be referenced. */
331 if (global_sym.symbol != NULL
332 && global_sym.block != block_static_block (global_sym.block))
335 fprintf_unfiltered (gdb_stdlog,
336 "gcc_convert_symbol \"%s\": global symbol\n",
338 convert_one_symbol (context, global_sym, 1, 0);
343 fprintf_unfiltered (gdb_stdlog,
344 "gcc_convert_symbol \"%s\": local symbol\n",
346 convert_one_symbol (context, sym, 0, is_local_symbol);
349 /* Convert a minimal symbol to its gcc form. CONTEXT is the compiler
350 to use and BMSYM is the minimal symbol to convert. */
353 convert_symbol_bmsym (struct compile_c_instance *context,
354 struct bound_minimal_symbol bmsym)
356 struct minimal_symbol *msym = bmsym.minsym;
357 struct objfile *objfile = bmsym.objfile;
359 enum gcc_c_symbol_kind kind;
364 addr = MSYMBOL_VALUE_ADDRESS (objfile, msym);
366 /* Conversion copied from write_exp_msymbol. */
367 switch (MSYMBOL_TYPE (msym))
371 case mst_solib_trampoline:
372 type = objfile_type (objfile)->nodebug_text_symbol;
373 kind = GCC_C_SYMBOL_FUNCTION;
376 case mst_text_gnu_ifunc:
377 type = objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
378 kind = GCC_C_SYMBOL_FUNCTION;
379 addr = gnu_ifunc_resolve_addr (target_gdbarch (), addr);
386 type = objfile_type (objfile)->nodebug_data_symbol;
387 kind = GCC_C_SYMBOL_VARIABLE;
390 case mst_slot_got_plt:
391 type = objfile_type (objfile)->nodebug_got_plt_symbol;
392 kind = GCC_C_SYMBOL_FUNCTION;
396 type = objfile_type (objfile)->nodebug_unknown_symbol;
397 kind = GCC_C_SYMBOL_VARIABLE;
401 sym_type = convert_type (context, type);
402 decl = context->c_plugin->build_decl (MSYMBOL_NATURAL_NAME (msym),
403 kind, sym_type, NULL, addr,
405 context->c_plugin->bind (decl, 1 /* is_global */);
408 /* See compile-internal.h. */
411 gcc_convert_symbol (void *datum,
412 struct gcc_c_context *gcc_context,
413 enum gcc_c_oracle_request request,
414 const char *identifier)
416 struct compile_c_instance *context = (struct compile_c_instance *) datum;
422 case GCC_C_ORACLE_SYMBOL:
425 case GCC_C_ORACLE_TAG:
426 domain = STRUCT_DOMAIN;
428 case GCC_C_ORACLE_LABEL:
429 domain = LABEL_DOMAIN;
432 gdb_assert_not_reached ("Unrecognized oracle request.");
435 /* We can't allow exceptions to escape out of this callback. Safest
436 is to simply emit a gcc error. */
439 struct block_symbol sym;
441 sym = lookup_symbol (identifier, context->base.block, domain, NULL);
442 if (sym.symbol != NULL)
444 convert_symbol_sym (context, identifier, sym, domain);
447 else if (domain == VAR_DOMAIN)
449 struct bound_minimal_symbol bmsym;
451 bmsym = lookup_minimal_symbol (identifier, NULL, NULL);
452 if (bmsym.minsym != NULL)
454 convert_symbol_bmsym (context, bmsym);
460 CATCH (e, RETURN_MASK_ALL)
462 context->c_plugin->error (e.message);
466 if (compile_debug && !found)
467 fprintf_unfiltered (gdb_stdlog,
468 "gcc_convert_symbol \"%s\": lookup_symbol failed\n",
473 /* See compile-internal.h. */
476 gcc_symbol_address (void *datum, struct gcc_c_context *gcc_context,
477 const char *identifier)
479 struct compile_c_instance *context = (struct compile_c_instance *) datum;
480 gcc_address result = 0;
483 /* We can't allow exceptions to escape out of this callback. Safest
484 is to simply emit a gcc error. */
489 /* We only need global functions here. */
490 sym = lookup_symbol (identifier, NULL, VAR_DOMAIN, NULL).symbol;
491 if (sym != NULL && SYMBOL_CLASS (sym) == LOC_BLOCK)
494 fprintf_unfiltered (gdb_stdlog,
495 "gcc_symbol_address \"%s\": full symbol\n",
497 result = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
498 if (TYPE_GNU_IFUNC (SYMBOL_TYPE (sym)))
499 result = gnu_ifunc_resolve_addr (target_gdbarch (), result);
504 struct bound_minimal_symbol msym;
506 msym = lookup_bound_minimal_symbol (identifier);
507 if (msym.minsym != NULL)
510 fprintf_unfiltered (gdb_stdlog,
511 "gcc_symbol_address \"%s\": minimal "
514 result = BMSYMBOL_VALUE_ADDRESS (msym);
515 if (MSYMBOL_TYPE (msym.minsym) == mst_text_gnu_ifunc)
516 result = gnu_ifunc_resolve_addr (target_gdbarch (), result);
522 CATCH (e, RETURN_MASK_ERROR)
524 context->c_plugin->error (e.message);
528 if (compile_debug && !found)
529 fprintf_unfiltered (gdb_stdlog,
530 "gcc_symbol_address \"%s\": failed\n",
537 /* A hash function for symbol names. */
540 hash_symname (const void *a)
542 const struct symbol *sym = (const struct symbol *) a;
544 return htab_hash_string (SYMBOL_NATURAL_NAME (sym));
547 /* A comparison function for hash tables that just looks at symbol
551 eq_symname (const void *a, const void *b)
553 const struct symbol *syma = (const struct symbol *) a;
554 const struct symbol *symb = (const struct symbol *) b;
556 return strcmp (SYMBOL_NATURAL_NAME (syma), SYMBOL_NATURAL_NAME (symb)) == 0;
559 /* If a symbol with the same name as SYM is already in HASHTAB, return
560 1. Otherwise, add SYM to HASHTAB and return 0. */
563 symbol_seen (htab_t hashtab, struct symbol *sym)
567 slot = htab_find_slot (hashtab, sym, INSERT);
575 /* Generate C code to compute the length of a VLA. */
578 generate_vla_size (struct compile_c_instance *compiler,
580 struct gdbarch *gdbarch,
581 unsigned char *registers_used,
586 type = check_typedef (type);
588 if (TYPE_IS_REFERENCE (type))
589 type = check_typedef (TYPE_TARGET_TYPE (type));
591 switch (TYPE_CODE (type))
593 case TYPE_CODE_RANGE:
595 if (TYPE_HIGH_BOUND_KIND (type) == PROP_LOCEXPR
596 || TYPE_HIGH_BOUND_KIND (type) == PROP_LOCLIST)
598 const struct dynamic_prop *prop = &TYPE_RANGE_DATA (type)->high;
599 std::string name = c_get_range_decl_name (prop);
601 dwarf2_compile_property_to_c (stream, name.c_str (),
602 gdbarch, registers_used,
608 case TYPE_CODE_ARRAY:
609 generate_vla_size (compiler, stream, gdbarch, registers_used, pc,
610 TYPE_INDEX_TYPE (type), sym);
611 generate_vla_size (compiler, stream, gdbarch, registers_used, pc,
612 TYPE_TARGET_TYPE (type), sym);
615 case TYPE_CODE_UNION:
616 case TYPE_CODE_STRUCT:
620 for (i = 0; i < TYPE_NFIELDS (type); ++i)
621 if (!field_is_static (&TYPE_FIELD (type, i)))
622 generate_vla_size (compiler, stream, gdbarch, registers_used, pc,
623 TYPE_FIELD_TYPE (type, i), sym);
629 /* Generate C code to compute the address of SYM. */
632 generate_c_for_for_one_variable (struct compile_c_instance *compiler,
634 struct gdbarch *gdbarch,
635 unsigned char *registers_used,
642 if (is_dynamic_type (SYMBOL_TYPE (sym)))
644 /* We need to emit to a temporary buffer in case an error
645 occurs in the middle. */
646 string_file local_file;
648 generate_vla_size (compiler, local_file, gdbarch, registers_used, pc,
649 SYMBOL_TYPE (sym), sym);
651 stream.write (local_file.c_str (), local_file.size ());
654 if (SYMBOL_COMPUTED_OPS (sym) != NULL)
656 gdb::unique_xmalloc_ptr<char> generated_name
657 = c_symbol_substitution_name (sym);
658 /* We need to emit to a temporary buffer in case an error
659 occurs in the middle. */
660 string_file local_file;
662 SYMBOL_COMPUTED_OPS (sym)->generate_c_location (sym, local_file,
666 generated_name.get ());
667 stream.write (local_file.c_str (), local_file.size ());
671 switch (SYMBOL_CLASS (sym))
676 case LOC_REGPARM_ADDR:
678 error (_("Local symbol unhandled when generating C code."));
681 gdb_assert_not_reached (_("LOC_COMPUTED variable "
682 "missing a method."));
685 /* Nothing to do for all other cases, as they don't represent
692 CATCH (e, RETURN_MASK_ERROR)
694 if (compiler->symbol_err_map == NULL)
695 compiler->symbol_err_map = htab_create_alloc (10,
701 insert_symbol_error (compiler->symbol_err_map, sym, e.message);
706 /* See compile-c.h. */
708 gdb::unique_xmalloc_ptr<unsigned char>
709 generate_c_for_variable_locations (struct compile_c_instance *compiler,
711 struct gdbarch *gdbarch,
712 const struct block *block,
715 const struct block *static_block = block_static_block (block);
717 /* If we're already in the static or global block, there is nothing
719 if (static_block == NULL || block == static_block)
722 gdb::unique_xmalloc_ptr<unsigned char> registers_used
723 (XCNEWVEC (unsigned char, gdbarch_num_regs (gdbarch)));
725 /* Ensure that a given name is only entered once. This reflects the
726 reality of shadowing. */
727 htab_up symhash (htab_create_alloc (1, hash_symname, eq_symname, NULL,
733 struct block_iterator iter;
735 /* Iterate over symbols in this block, generating code to
736 compute the location of each local variable. */
737 for (sym = block_iterator_first (block, &iter);
739 sym = block_iterator_next (&iter))
741 if (!symbol_seen (symhash.get (), sym))
742 generate_c_for_for_one_variable (compiler, stream, gdbarch,
743 registers_used.get (), pc, sym);
746 /* If we just finished the outermost block of a function, we're
748 if (BLOCK_FUNCTION (block) != NULL)
750 block = BLOCK_SUPERBLOCK (block);
753 return registers_used;