1 /* Parse expressions for GDB.
3 Copyright (C) 1986-2017 Free Software Foundation, Inc.
5 Modified from expread.y by the Department of Computer Science at the
6 State University of New York at Buffalo, 1991.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 /* Parse an expression from text in a string,
24 and return the result as a struct expression pointer.
25 That structure contains arithmetic operations in reverse polish,
26 with constants represented by operations that are followed by special data.
27 See expression.h for the details of the format.
28 What is important here is that it can be built up sequentially
29 during the process of parsing; the lower levels of the tree always
30 come first in the result. */
34 #include "arch-utils.h"
38 #include "expression.h"
43 #include "parser-defs.h"
45 #include "symfile.h" /* for overlay functions */
51 #include "user-regs.h"
53 #include "common/gdb_optional.h"
55 /* Standard set of definitions for printing, dumping, prefixifying,
56 * and evaluating expressions. */
58 const struct exp_descriptor exp_descriptor_standard =
60 print_subexp_standard,
61 operator_length_standard,
62 operator_check_standard,
64 dump_subexp_body_standard,
65 evaluate_subexp_standard
68 /* Global variables declared in parser-defs.h (and commented there). */
69 const struct block *expression_context_block;
70 CORE_ADDR expression_context_pc;
71 const struct block *innermost_block;
73 static struct type_stack type_stack;
75 const char *prev_lexptr;
79 /* True if parsing an expression to attempt completion. */
82 /* The index of the last struct expression directly before a '.' or
83 '->'. This is set when parsing and is only used when completing a
84 field name. It is -1 if no dereference operation was found. */
85 static int expout_last_struct = -1;
87 /* If we are completing a tagged type name, this will be nonzero. */
88 static enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;
90 /* The token for tagged type name completion. */
91 static char *expout_completion_name;
94 static unsigned int expressiondebug = 0;
96 show_expressiondebug (struct ui_file *file, int from_tty,
97 struct cmd_list_element *c, const char *value)
99 fprintf_filtered (file, _("Expression debugging is %s.\n"), value);
103 /* Non-zero if an expression parser should set yydebug. */
107 show_parserdebug (struct ui_file *file, int from_tty,
108 struct cmd_list_element *c, const char *value)
110 fprintf_filtered (file, _("Parser debugging is %s.\n"), value);
114 static void free_funcalls (void *ignore);
116 static int prefixify_subexp (struct expression *, struct expression *, int,
119 static expression_up parse_exp_in_context (const char **, CORE_ADDR,
120 const struct block *, int,
122 static expression_up parse_exp_in_context_1 (const char **, CORE_ADDR,
123 const struct block *, int,
126 void _initialize_parse (void);
128 /* Data structure for saving values of arglist_len for function calls whose
129 arguments contain other function calls. */
133 struct funcall *next;
137 static struct funcall *funcall_chain;
139 /* Begin counting arguments for a function call,
140 saving the data about any containing call. */
145 struct funcall *newobj;
147 newobj = XNEW (struct funcall);
148 newobj->next = funcall_chain;
149 newobj->arglist_len = arglist_len;
151 funcall_chain = newobj;
154 /* Return the number of arguments in a function call just terminated,
155 and restore the data for the containing function call. */
160 int val = arglist_len;
161 struct funcall *call = funcall_chain;
163 funcall_chain = call->next;
164 arglist_len = call->arglist_len;
169 /* Free everything in the funcall chain.
170 Used when there is an error inside parsing. */
173 free_funcalls (void *ignore)
175 struct funcall *call, *next;
177 for (call = funcall_chain; call; call = next)
185 /* See definition in parser-defs.h. */
188 initialize_expout (struct parser_state *ps, size_t initial_size,
189 const struct language_defn *lang,
190 struct gdbarch *gdbarch)
192 ps->expout_size = initial_size;
195 = (struct expression *) xmalloc (sizeof (struct expression)
196 + EXP_ELEM_TO_BYTES (ps->expout_size));
197 ps->expout->language_defn = lang;
198 ps->expout->gdbarch = gdbarch;
201 /* See definition in parser-defs.h. */
204 reallocate_expout (struct parser_state *ps)
206 /* Record the actual number of expression elements, and then
207 reallocate the expression memory so that we free up any
210 ps->expout->nelts = ps->expout_ptr;
211 ps->expout = (struct expression *)
212 xrealloc (ps->expout,
213 sizeof (struct expression)
214 + EXP_ELEM_TO_BYTES (ps->expout_ptr));
217 /* This page contains the functions for adding data to the struct expression
218 being constructed. */
220 /* Add one element to the end of the expression. */
222 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
223 a register through here. */
226 write_exp_elt (struct parser_state *ps, const union exp_element *expelt)
228 if (ps->expout_ptr >= ps->expout_size)
230 ps->expout_size *= 2;
231 ps->expout = (struct expression *)
232 xrealloc (ps->expout, sizeof (struct expression)
233 + EXP_ELEM_TO_BYTES (ps->expout_size));
235 ps->expout->elts[ps->expout_ptr++] = *expelt;
239 write_exp_elt_opcode (struct parser_state *ps, enum exp_opcode expelt)
241 union exp_element tmp;
243 memset (&tmp, 0, sizeof (union exp_element));
245 write_exp_elt (ps, &tmp);
249 write_exp_elt_sym (struct parser_state *ps, struct symbol *expelt)
251 union exp_element tmp;
253 memset (&tmp, 0, sizeof (union exp_element));
255 write_exp_elt (ps, &tmp);
259 write_exp_elt_msym (struct parser_state *ps, minimal_symbol *expelt)
261 union exp_element tmp;
263 memset (&tmp, 0, sizeof (union exp_element));
264 tmp.msymbol = expelt;
265 write_exp_elt (ps, &tmp);
269 write_exp_elt_block (struct parser_state *ps, const struct block *b)
271 union exp_element tmp;
273 memset (&tmp, 0, sizeof (union exp_element));
275 write_exp_elt (ps, &tmp);
279 write_exp_elt_objfile (struct parser_state *ps, struct objfile *objfile)
281 union exp_element tmp;
283 memset (&tmp, 0, sizeof (union exp_element));
284 tmp.objfile = objfile;
285 write_exp_elt (ps, &tmp);
289 write_exp_elt_longcst (struct parser_state *ps, LONGEST expelt)
291 union exp_element tmp;
293 memset (&tmp, 0, sizeof (union exp_element));
294 tmp.longconst = expelt;
295 write_exp_elt (ps, &tmp);
299 write_exp_elt_dblcst (struct parser_state *ps, DOUBLEST expelt)
301 union exp_element tmp;
303 memset (&tmp, 0, sizeof (union exp_element));
304 tmp.doubleconst = expelt;
305 write_exp_elt (ps, &tmp);
309 write_exp_elt_decfloatcst (struct parser_state *ps, gdb_byte expelt[16])
311 union exp_element tmp;
314 for (index = 0; index < 16; index++)
315 tmp.decfloatconst[index] = expelt[index];
317 write_exp_elt (ps, &tmp);
321 write_exp_elt_type (struct parser_state *ps, struct type *expelt)
323 union exp_element tmp;
325 memset (&tmp, 0, sizeof (union exp_element));
327 write_exp_elt (ps, &tmp);
331 write_exp_elt_intern (struct parser_state *ps, struct internalvar *expelt)
333 union exp_element tmp;
335 memset (&tmp, 0, sizeof (union exp_element));
336 tmp.internalvar = expelt;
337 write_exp_elt (ps, &tmp);
340 /* Add a string constant to the end of the expression.
342 String constants are stored by first writing an expression element
343 that contains the length of the string, then stuffing the string
344 constant itself into however many expression elements are needed
345 to hold it, and then writing another expression element that contains
346 the length of the string. I.e. an expression element at each end of
347 the string records the string length, so you can skip over the
348 expression elements containing the actual string bytes from either
349 end of the string. Note that this also allows gdb to handle
350 strings with embedded null bytes, as is required for some languages.
352 Don't be fooled by the fact that the string is null byte terminated,
353 this is strictly for the convenience of debugging gdb itself.
354 Gdb does not depend up the string being null terminated, since the
355 actual length is recorded in expression elements at each end of the
356 string. The null byte is taken into consideration when computing how
357 many expression elements are required to hold the string constant, of
362 write_exp_string (struct parser_state *ps, struct stoken str)
364 int len = str.length;
368 /* Compute the number of expression elements required to hold the string
369 (including a null byte terminator), along with one expression element
370 at each end to record the actual string length (not including the
371 null byte terminator). */
373 lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);
375 increase_expout_size (ps, lenelt);
377 /* Write the leading length expression element (which advances the current
378 expression element index), then write the string constant followed by a
379 terminating null byte, and then write the trailing length expression
382 write_exp_elt_longcst (ps, (LONGEST) len);
383 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
384 memcpy (strdata, str.ptr, len);
385 *(strdata + len) = '\0';
386 ps->expout_ptr += lenelt - 2;
387 write_exp_elt_longcst (ps, (LONGEST) len);
390 /* Add a vector of string constants to the end of the expression.
392 This adds an OP_STRING operation, but encodes the contents
393 differently from write_exp_string. The language is expected to
394 handle evaluation of this expression itself.
396 After the usual OP_STRING header, TYPE is written into the
397 expression as a long constant. The interpretation of this field is
398 up to the language evaluator.
400 Next, each string in VEC is written. The length is written as a
401 long constant, followed by the contents of the string. */
404 write_exp_string_vector (struct parser_state *ps, int type,
405 struct stoken_vector *vec)
410 /* Compute the size. We compute the size in number of slots to
411 avoid issues with string padding. */
413 for (i = 0; i < vec->len; ++i)
415 /* One slot for the length of this element, plus the number of
416 slots needed for this string. */
417 n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
420 /* One more slot for the type of the string. */
423 /* Now compute a phony string length. */
424 len = EXP_ELEM_TO_BYTES (n_slots) - 1;
427 increase_expout_size (ps, n_slots);
429 write_exp_elt_opcode (ps, OP_STRING);
430 write_exp_elt_longcst (ps, len);
431 write_exp_elt_longcst (ps, type);
433 for (i = 0; i < vec->len; ++i)
435 write_exp_elt_longcst (ps, vec->tokens[i].length);
436 memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr,
437 vec->tokens[i].length);
438 ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
441 write_exp_elt_longcst (ps, len);
442 write_exp_elt_opcode (ps, OP_STRING);
445 /* Add a bitstring constant to the end of the expression.
447 Bitstring constants are stored by first writing an expression element
448 that contains the length of the bitstring (in bits), then stuffing the
449 bitstring constant itself into however many expression elements are
450 needed to hold it, and then writing another expression element that
451 contains the length of the bitstring. I.e. an expression element at
452 each end of the bitstring records the bitstring length, so you can skip
453 over the expression elements containing the actual bitstring bytes from
454 either end of the bitstring. */
457 write_exp_bitstring (struct parser_state *ps, struct stoken str)
459 int bits = str.length; /* length in bits */
460 int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
464 /* Compute the number of expression elements required to hold the bitstring,
465 along with one expression element at each end to record the actual
466 bitstring length in bits. */
468 lenelt = 2 + BYTES_TO_EXP_ELEM (len);
470 increase_expout_size (ps, lenelt);
472 /* Write the leading length expression element (which advances the current
473 expression element index), then write the bitstring constant, and then
474 write the trailing length expression element. */
476 write_exp_elt_longcst (ps, (LONGEST) bits);
477 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
478 memcpy (strdata, str.ptr, len);
479 ps->expout_ptr += lenelt - 2;
480 write_exp_elt_longcst (ps, (LONGEST) bits);
483 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
484 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
488 find_minsym_type_and_address (minimal_symbol *msymbol,
489 struct objfile *objfile,
490 CORE_ADDR *address_p)
492 bound_minimal_symbol bound_msym = {msymbol, objfile};
493 struct gdbarch *gdbarch = get_objfile_arch (objfile);
494 CORE_ADDR addr = BMSYMBOL_VALUE_ADDRESS (bound_msym);
495 struct obj_section *section = MSYMBOL_OBJ_SECTION (objfile, msymbol);
496 enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
499 /* The minimal symbol might point to a function descriptor;
500 resolve it to the actual code address instead. */
501 pc = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, ¤t_target);
504 struct bound_minimal_symbol ifunc_msym = lookup_minimal_symbol_by_pc (pc);
506 /* In this case, assume we have a code symbol instead of
509 if (ifunc_msym.minsym != NULL
510 && MSYMBOL_TYPE (ifunc_msym.minsym) == mst_text_gnu_ifunc
511 && BMSYMBOL_VALUE_ADDRESS (ifunc_msym) == pc)
513 /* A function descriptor has been resolved but PC is still in the
514 STT_GNU_IFUNC resolver body (such as because inferior does not
515 run to be able to call it). */
517 type = mst_text_gnu_ifunc;
525 if (overlay_debugging)
526 addr = symbol_overlayed_address (addr, section);
528 if (section && section->the_bfd_section->flags & SEC_THREAD_LOCAL)
530 /* Skip translation if caller does not need the address. */
531 if (address_p != NULL)
532 *address_p = target_translate_tls_address (objfile, addr);
533 return objfile_type (objfile)->nodebug_tls_symbol;
536 if (address_p != NULL)
539 struct type *the_type;
545 case mst_solib_trampoline:
546 return objfile_type (objfile)->nodebug_text_symbol;
548 case mst_text_gnu_ifunc:
549 return objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
555 return objfile_type (objfile)->nodebug_data_symbol;
557 case mst_slot_got_plt:
558 return objfile_type (objfile)->nodebug_got_plt_symbol;
561 return objfile_type (objfile)->nodebug_unknown_symbol;
565 /* Add the appropriate elements for a minimal symbol to the end of
569 write_exp_msymbol (struct parser_state *ps,
570 struct bound_minimal_symbol bound_msym)
572 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
573 write_exp_elt_objfile (ps, bound_msym.objfile);
574 write_exp_elt_msym (ps, bound_msym.minsym);
575 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
578 /* Mark the current index as the starting location of a structure
579 expression. This is used when completing on field names. */
582 mark_struct_expression (struct parser_state *ps)
584 gdb_assert (parse_completion
585 && expout_tag_completion_type == TYPE_CODE_UNDEF);
586 expout_last_struct = ps->expout_ptr;
589 /* Indicate that the current parser invocation is completing a tag.
590 TAG is the type code of the tag, and PTR and LENGTH represent the
591 start of the tag name. */
594 mark_completion_tag (enum type_code tag, const char *ptr, int length)
596 gdb_assert (parse_completion
597 && expout_tag_completion_type == TYPE_CODE_UNDEF
598 && expout_completion_name == NULL
599 && expout_last_struct == -1);
600 gdb_assert (tag == TYPE_CODE_UNION
601 || tag == TYPE_CODE_STRUCT
602 || tag == TYPE_CODE_ENUM);
603 expout_tag_completion_type = tag;
604 expout_completion_name = (char *) xmalloc (length + 1);
605 memcpy (expout_completion_name, ptr, length);
606 expout_completion_name[length] = '\0';
610 /* Recognize tokens that start with '$'. These include:
612 $regname A native register name or a "standard
615 $variable A convenience variable with a name chosen
618 $digits Value history with index <digits>, starting
619 from the first value which has index 1.
621 $$digits Value history with index <digits> relative
622 to the last value. I.e. $$0 is the last
623 value, $$1 is the one previous to that, $$2
624 is the one previous to $$1, etc.
626 $ | $0 | $$0 The last value in the value history.
628 $$ An abbreviation for the second to the last
629 value in the value history, I.e. $$1 */
632 write_dollar_variable (struct parser_state *ps, struct stoken str)
634 struct block_symbol sym;
635 struct bound_minimal_symbol msym;
636 struct internalvar *isym = NULL;
638 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
639 and $$digits (equivalent to $<-digits> if you could type that). */
643 /* Double dollar means negate the number and add -1 as well.
644 Thus $$ alone means -1. */
645 if (str.length >= 2 && str.ptr[1] == '$')
652 /* Just dollars (one or two). */
656 /* Is the rest of the token digits? */
657 for (; i < str.length; i++)
658 if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
662 i = atoi (str.ptr + 1 + negate);
668 /* Handle tokens that refer to machine registers:
669 $ followed by a register name. */
670 i = user_reg_map_name_to_regnum (parse_gdbarch (ps),
671 str.ptr + 1, str.length - 1);
673 goto handle_register;
675 /* Any names starting with $ are probably debugger internal variables. */
677 isym = lookup_only_internalvar (copy_name (str) + 1);
680 write_exp_elt_opcode (ps, OP_INTERNALVAR);
681 write_exp_elt_intern (ps, isym);
682 write_exp_elt_opcode (ps, OP_INTERNALVAR);
686 /* On some systems, such as HP-UX and hppa-linux, certain system routines
687 have names beginning with $ or $$. Check for those, first. */
689 sym = lookup_symbol (copy_name (str), (struct block *) NULL,
693 write_exp_elt_opcode (ps, OP_VAR_VALUE);
694 write_exp_elt_block (ps, sym.block);
695 write_exp_elt_sym (ps, sym.symbol);
696 write_exp_elt_opcode (ps, OP_VAR_VALUE);
699 msym = lookup_bound_minimal_symbol (copy_name (str));
702 write_exp_msymbol (ps, msym);
706 /* Any other names are assumed to be debugger internal variables. */
708 write_exp_elt_opcode (ps, OP_INTERNALVAR);
709 write_exp_elt_intern (ps, create_internalvar (copy_name (str) + 1));
710 write_exp_elt_opcode (ps, OP_INTERNALVAR);
713 write_exp_elt_opcode (ps, OP_LAST);
714 write_exp_elt_longcst (ps, (LONGEST) i);
715 write_exp_elt_opcode (ps, OP_LAST);
718 write_exp_elt_opcode (ps, OP_REGISTER);
721 write_exp_string (ps, str);
722 write_exp_elt_opcode (ps, OP_REGISTER);
728 find_template_name_end (const char *p)
731 int just_seen_right = 0;
732 int just_seen_colon = 0;
733 int just_seen_space = 0;
735 if (!p || (*p != '<'))
746 /* In future, may want to allow these?? */
749 depth++; /* start nested template */
750 if (just_seen_colon || just_seen_right || just_seen_space)
751 return 0; /* but not after : or :: or > or space */
754 if (just_seen_colon || just_seen_right)
755 return 0; /* end a (nested?) template */
756 just_seen_right = 1; /* but not after : or :: */
757 if (--depth == 0) /* also disallow >>, insist on > > */
758 return ++p; /* if outermost ended, return */
761 if (just_seen_space || (just_seen_colon > 1))
762 return 0; /* nested class spec coming up */
763 just_seen_colon++; /* we allow :: but not :::: */
768 if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
769 (*p >= 'A' && *p <= 'Z') ||
770 (*p >= '0' && *p <= '9') ||
771 (*p == '_') || (*p == ',') || /* commas for template args */
772 (*p == '&') || (*p == '*') || /* pointer and ref types */
773 (*p == '(') || (*p == ')') || /* function types */
774 (*p == '[') || (*p == ']'))) /* array types */
788 /* Return a null-terminated temporary copy of the name of a string token.
790 Tokens that refer to names do so with explicit pointer and length,
791 so they can share the storage that lexptr is parsing.
792 When it is necessary to pass a name to a function that expects
793 a null-terminated string, the substring is copied out
794 into a separate block of storage.
796 N.B. A single buffer is reused on each call. */
799 copy_name (struct stoken token)
801 /* A temporary buffer for identifiers, so we can null-terminate them.
802 We allocate this with xrealloc. parse_exp_1 used to allocate with
803 alloca, using the size of the whole expression as a conservative
804 estimate of the space needed. However, macro expansion can
805 introduce names longer than the original expression; there's no
806 practical way to know beforehand how large that might be. */
807 static char *namecopy;
808 static size_t namecopy_size;
810 /* Make sure there's enough space for the token. */
811 if (namecopy_size < token.length + 1)
813 namecopy_size = token.length + 1;
814 namecopy = (char *) xrealloc (namecopy, token.length + 1);
817 memcpy (namecopy, token.ptr, token.length);
818 namecopy[token.length] = 0;
824 /* See comments on parser-defs.h. */
827 prefixify_expression (struct expression *expr)
829 int len = sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts);
830 struct expression *temp;
831 int inpos = expr->nelts, outpos = 0;
833 temp = (struct expression *) alloca (len);
835 /* Copy the original expression into temp. */
836 memcpy (temp, expr, len);
838 return prefixify_subexp (temp, expr, inpos, outpos);
841 /* Return the number of exp_elements in the postfix subexpression
842 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
845 length_of_subexp (struct expression *expr, int endpos)
849 operator_length (expr, endpos, &oplen, &args);
853 oplen += length_of_subexp (expr, endpos - oplen);
860 /* Sets *OPLENP to the length of the operator whose (last) index is
861 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
865 operator_length (const struct expression *expr, int endpos, int *oplenp,
868 expr->language_defn->la_exp_desc->operator_length (expr, endpos,
872 /* Default value for operator_length in exp_descriptor vectors. */
875 operator_length_standard (const struct expression *expr, int endpos,
876 int *oplenp, int *argsp)
880 enum range_type range_type;
884 error (_("?error in operator_length_standard"));
886 i = (int) expr->elts[endpos - 1].opcode;
892 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
893 oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
900 case OP_VAR_MSYM_VALUE:
908 case OP_VAR_ENTRY_VALUE:
918 case OP_F77_UNDETERMINED_ARGLIST:
920 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
924 oplen = 4 + longest_to_int (expr->elts[endpos - 2].longconst);
928 case OP_OBJC_MSGCALL: /* Objective C message (method) call. */
930 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
939 case UNOP_DYNAMIC_CAST:
940 case UNOP_REINTERPRET_CAST:
941 case UNOP_MEMVAL_TYPE:
969 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
970 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
975 case STRUCTOP_STRUCT:
982 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
983 NSString constant. */
984 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
986 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
987 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
992 args = longest_to_int (expr->elts[endpos - 2].longconst);
993 args -= longest_to_int (expr->elts[endpos - 3].longconst);
1003 case MULTI_SUBSCRIPT:
1005 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
1008 case BINOP_ASSIGN_MODIFY:
1020 range_type = (enum range_type)
1021 longest_to_int (expr->elts[endpos - 2].longconst);
1025 case LOW_BOUND_DEFAULT:
1026 case HIGH_BOUND_DEFAULT:
1029 case BOTH_BOUND_DEFAULT:
1032 case NONE_BOUND_DEFAULT:
1040 args = 1 + (i < (int) BINOP_END);
1047 /* Copy the subexpression ending just before index INEND in INEXPR
1048 into OUTEXPR, starting at index OUTBEG.
1049 In the process, convert it from suffix to prefix form.
1050 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1051 Otherwise, it returns the index of the subexpression which is the
1052 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1055 prefixify_subexp (struct expression *inexpr,
1056 struct expression *outexpr, int inend, int outbeg)
1064 operator_length (inexpr, inend, &oplen, &args);
1066 /* Copy the final operator itself, from the end of the input
1067 to the beginning of the output. */
1069 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1070 EXP_ELEM_TO_BYTES (oplen));
1073 if (expout_last_struct == inend)
1074 result = outbeg - oplen;
1076 /* Find the lengths of the arg subexpressions. */
1077 arglens = (int *) alloca (args * sizeof (int));
1078 for (i = args - 1; i >= 0; i--)
1080 oplen = length_of_subexp (inexpr, inend);
1085 /* Now copy each subexpression, preserving the order of
1086 the subexpressions, but prefixifying each one.
1087 In this loop, inend starts at the beginning of
1088 the expression this level is working on
1089 and marches forward over the arguments.
1090 outbeg does similarly in the output. */
1091 for (i = 0; i < args; i++)
1097 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1100 /* Return immediately. We probably have only parsed a
1101 partial expression, so we don't want to try to reverse
1102 the other operands. */
1111 /* Read an expression from the string *STRINGPTR points to,
1112 parse it, and return a pointer to a struct expression that we malloc.
1113 Use block BLOCK as the lexical context for variable names;
1114 if BLOCK is zero, use the block of the selected stack frame.
1115 Meanwhile, advance *STRINGPTR to point after the expression,
1116 at the first nonwhite character that is not part of the expression
1117 (possibly a null character).
1119 If COMMA is nonzero, stop if a comma is reached. */
1122 parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
1125 return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL);
1128 static expression_up
1129 parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
1130 const struct block *block,
1131 int comma, int void_context_p, int *out_subexp)
1133 return parse_exp_in_context_1 (stringptr, pc, block, comma,
1134 void_context_p, out_subexp);
1137 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1138 no value is expected from the expression.
1139 OUT_SUBEXP is set when attempting to complete a field name; in this
1140 case it is set to the index of the subexpression on the
1141 left-hand-side of the struct op. If not doing such completion, it
1142 is left untouched. */
1144 static expression_up
1145 parse_exp_in_context_1 (const char **stringptr, CORE_ADDR pc,
1146 const struct block *block,
1147 int comma, int void_context_p, int *out_subexp)
1149 struct cleanup *old_chain;
1150 const struct language_defn *lang = NULL;
1151 struct parser_state ps;
1154 lexptr = *stringptr;
1158 type_stack.depth = 0;
1159 expout_last_struct = -1;
1160 expout_tag_completion_type = TYPE_CODE_UNDEF;
1161 xfree (expout_completion_name);
1162 expout_completion_name = NULL;
1164 comma_terminates = comma;
1166 if (lexptr == 0 || *lexptr == 0)
1167 error_no_arg (_("expression to compute"));
1169 old_chain = make_cleanup (free_funcalls, 0 /*ignore*/);
1172 expression_context_block = block;
1174 /* If no context specified, try using the current frame, if any. */
1175 if (!expression_context_block)
1176 expression_context_block = get_selected_block (&expression_context_pc);
1178 expression_context_pc = BLOCK_START (expression_context_block);
1180 expression_context_pc = pc;
1182 /* Fall back to using the current source static context, if any. */
1184 if (!expression_context_block)
1186 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1188 expression_context_block
1189 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
1191 if (expression_context_block)
1192 expression_context_pc = BLOCK_START (expression_context_block);
1195 if (language_mode == language_mode_auto && block != NULL)
1197 /* Find the language associated to the given context block.
1198 Default to the current language if it can not be determined.
1200 Note that using the language corresponding to the current frame
1201 can sometimes give unexpected results. For instance, this
1202 routine is often called several times during the inferior
1203 startup phase to re-parse breakpoint expressions after
1204 a new shared library has been loaded. The language associated
1205 to the current frame at this moment is not relevant for
1206 the breakpoint. Using it would therefore be silly, so it seems
1207 better to rely on the current language rather than relying on
1208 the current frame language to parse the expression. That's why
1209 we do the following language detection only if the context block
1210 has been specifically provided. */
1211 struct symbol *func = block_linkage_function (block);
1214 lang = language_def (SYMBOL_LANGUAGE (func));
1215 if (lang == NULL || lang->la_language == language_unknown)
1216 lang = current_language;
1219 lang = current_language;
1221 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1222 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1223 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1224 to the value matching SELECTED_FRAME as set by get_current_arch. */
1226 initialize_expout (&ps, 10, lang, get_current_arch ());
1228 scoped_restore_current_language lang_saver;
1229 set_language (lang->la_language);
1233 if (lang->la_parser (&ps))
1234 lang->la_error (NULL);
1236 CATCH (except, RETURN_MASK_ALL)
1238 if (! parse_completion)
1241 throw_exception (except);
1246 reallocate_expout (&ps);
1248 /* Convert expression from postfix form as generated by yacc
1249 parser, to a prefix form. */
1251 if (expressiondebug)
1252 dump_raw_expression (ps.expout, gdb_stdlog,
1253 "before conversion to prefix form");
1255 subexp = prefixify_expression (ps.expout);
1257 *out_subexp = subexp;
1259 lang->la_post_parser (&ps.expout, void_context_p);
1261 if (expressiondebug)
1262 dump_prefix_expression (ps.expout, gdb_stdlog);
1264 discard_cleanups (old_chain);
1266 *stringptr = lexptr;
1267 return expression_up (ps.expout);
1270 /* Parse STRING as an expression, and complain if this fails
1271 to use up all of the contents of STRING. */
1274 parse_expression (const char *string)
1276 expression_up exp = parse_exp_1 (&string, 0, 0, 0);
1278 error (_("Junk after end of expression."));
1282 /* Same as parse_expression, but using the given language (LANG)
1283 to parse the expression. */
1286 parse_expression_with_language (const char *string, enum language lang)
1288 gdb::optional<scoped_restore_current_language> lang_saver;
1289 if (current_language->la_language != lang)
1291 lang_saver.emplace ();
1292 set_language (lang);
1295 return parse_expression (string);
1298 /* Parse STRING as an expression. If parsing ends in the middle of a
1299 field reference, return the type of the left-hand-side of the
1300 reference; furthermore, if the parsing ends in the field name,
1301 return the field name in *NAME. If the parsing ends in the middle
1302 of a field reference, but the reference is somehow invalid, throw
1303 an exception. In all other cases, return NULL. Returned non-NULL
1304 *NAME must be freed by the caller. */
1307 parse_expression_for_completion (const char *string, char **name,
1308 enum type_code *code)
1316 parse_completion = 1;
1317 exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp);
1319 CATCH (except, RETURN_MASK_ERROR)
1321 /* Nothing, EXP remains NULL. */
1325 parse_completion = 0;
1329 if (expout_tag_completion_type != TYPE_CODE_UNDEF)
1331 *code = expout_tag_completion_type;
1332 *name = expout_completion_name;
1333 expout_completion_name = NULL;
1337 if (expout_last_struct == -1)
1340 *name = extract_field_op (exp.get (), &subexp);
1344 /* This might throw an exception. If so, we want to let it
1346 val = evaluate_subexpression_type (exp.get (), subexp);
1347 /* (*NAME) is a part of the EXP memory block freed below. */
1348 *name = xstrdup (*name);
1350 return value_type (val);
1353 /* A post-parser that does nothing. */
1356 null_post_parser (struct expression **exp, int void_context_p)
1360 /* Parse floating point value P of length LEN.
1361 Return 0 (false) if invalid, 1 (true) if valid.
1362 The successfully parsed number is stored in D.
1363 *SUFFIX points to the suffix of the number in P.
1365 NOTE: This accepts the floating point syntax that sscanf accepts. */
1368 parse_float (const char *p, int len, DOUBLEST *d, const char **suffix)
1373 copy = (char *) xmalloc (len + 1);
1374 memcpy (copy, p, len);
1377 num = sscanf (copy, "%" DOUBLEST_SCAN_FORMAT "%n", d, &n);
1380 /* The sscanf man page suggests not making any assumptions on the effect
1381 of %n on the result, so we don't.
1382 That is why we simply test num == 0. */
1390 /* Parse floating point value P of length LEN, using the C syntax for floats.
1391 Return 0 (false) if invalid, 1 (true) if valid.
1392 The successfully parsed number is stored in *D.
1393 Its type is taken from builtin_type (gdbarch) and is stored in *T. */
1396 parse_c_float (struct gdbarch *gdbarch, const char *p, int len,
1397 DOUBLEST *d, struct type **t)
1401 const struct builtin_type *builtin_types = builtin_type (gdbarch);
1403 if (! parse_float (p, len, d, &suffix))
1406 suffix_len = p + len - suffix;
1408 if (suffix_len == 0)
1409 *t = builtin_types->builtin_double;
1410 else if (suffix_len == 1)
1412 /* Handle suffixes: 'f' for float, 'l' for long double. */
1413 if (tolower (*suffix) == 'f')
1414 *t = builtin_types->builtin_float;
1415 else if (tolower (*suffix) == 'l')
1416 *t = builtin_types->builtin_long_double;
1426 /* Stuff for maintaining a stack of types. Currently just used by C, but
1427 probably useful for any language which declares its types "backwards". */
1429 /* Ensure that there are HOWMUCH open slots on the type stack STACK. */
1432 type_stack_reserve (struct type_stack *stack, int howmuch)
1434 if (stack->depth + howmuch >= stack->size)
1437 if (stack->size < howmuch)
1438 stack->size = howmuch;
1439 stack->elements = XRESIZEVEC (union type_stack_elt, stack->elements,
1444 /* Ensure that there is a single open slot in the global type stack. */
1447 check_type_stack_depth (void)
1449 type_stack_reserve (&type_stack, 1);
1452 /* A helper function for insert_type and insert_type_address_space.
1453 This does work of expanding the type stack and inserting the new
1454 element, ELEMENT, into the stack at location SLOT. */
1457 insert_into_type_stack (int slot, union type_stack_elt element)
1459 check_type_stack_depth ();
1461 if (slot < type_stack.depth)
1462 memmove (&type_stack.elements[slot + 1], &type_stack.elements[slot],
1463 (type_stack.depth - slot) * sizeof (union type_stack_elt));
1464 type_stack.elements[slot] = element;
1468 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1469 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1470 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1471 previous tp_pointer) if there is anything on the stack, or simply pushed
1472 if the stack is empty. Other values for TP are invalid. */
1475 insert_type (enum type_pieces tp)
1477 union type_stack_elt element;
1480 gdb_assert (tp == tp_pointer || tp == tp_reference
1481 || tp == tp_rvalue_reference || tp == tp_const
1482 || tp == tp_volatile);
1484 /* If there is anything on the stack (we know it will be a
1485 tp_pointer), insert the qualifier above it. Otherwise, simply
1486 push this on the top of the stack. */
1487 if (type_stack.depth && (tp == tp_const || tp == tp_volatile))
1493 insert_into_type_stack (slot, element);
1497 push_type (enum type_pieces tp)
1499 check_type_stack_depth ();
1500 type_stack.elements[type_stack.depth++].piece = tp;
1504 push_type_int (int n)
1506 check_type_stack_depth ();
1507 type_stack.elements[type_stack.depth++].int_val = n;
1510 /* Insert a tp_space_identifier and the corresponding address space
1511 value into the stack. STRING is the name of an address space, as
1512 recognized by address_space_name_to_int. If the stack is empty,
1513 the new elements are simply pushed. If the stack is not empty,
1514 this function assumes that the first item on the stack is a
1515 tp_pointer, and the new values are inserted above the first
1519 insert_type_address_space (struct parser_state *pstate, char *string)
1521 union type_stack_elt element;
1524 /* If there is anything on the stack (we know it will be a
1525 tp_pointer), insert the address space qualifier above it.
1526 Otherwise, simply push this on the top of the stack. */
1527 if (type_stack.depth)
1532 element.piece = tp_space_identifier;
1533 insert_into_type_stack (slot, element);
1534 element.int_val = address_space_name_to_int (parse_gdbarch (pstate),
1536 insert_into_type_stack (slot, element);
1542 if (type_stack.depth)
1543 return type_stack.elements[--type_stack.depth].piece;
1550 if (type_stack.depth)
1551 return type_stack.elements[--type_stack.depth].int_val;
1552 /* "Can't happen". */
1556 /* Pop a type list element from the global type stack. */
1558 static VEC (type_ptr) *
1561 gdb_assert (type_stack.depth);
1562 return type_stack.elements[--type_stack.depth].typelist_val;
1565 /* Pop a type_stack element from the global type stack. */
1567 static struct type_stack *
1568 pop_type_stack (void)
1570 gdb_assert (type_stack.depth);
1571 return type_stack.elements[--type_stack.depth].stack_val;
1574 /* Append the elements of the type stack FROM to the type stack TO.
1575 Always returns TO. */
1578 append_type_stack (struct type_stack *to, struct type_stack *from)
1580 type_stack_reserve (to, from->depth);
1582 memcpy (&to->elements[to->depth], &from->elements[0],
1583 from->depth * sizeof (union type_stack_elt));
1584 to->depth += from->depth;
1589 /* Push the type stack STACK as an element on the global type stack. */
1592 push_type_stack (struct type_stack *stack)
1594 check_type_stack_depth ();
1595 type_stack.elements[type_stack.depth++].stack_val = stack;
1596 push_type (tp_type_stack);
1599 /* Copy the global type stack into a newly allocated type stack and
1600 return it. The global stack is cleared. The returned type stack
1601 must be freed with type_stack_cleanup. */
1604 get_type_stack (void)
1606 struct type_stack *result = XNEW (struct type_stack);
1608 *result = type_stack;
1609 type_stack.depth = 0;
1610 type_stack.size = 0;
1611 type_stack.elements = NULL;
1616 /* A cleanup function that destroys a single type stack. */
1619 type_stack_cleanup (void *arg)
1621 struct type_stack *stack = (struct type_stack *) arg;
1623 xfree (stack->elements);
1627 /* Push a function type with arguments onto the global type stack.
1628 LIST holds the argument types. If the final item in LIST is NULL,
1629 then the function will be varargs. */
1632 push_typelist (VEC (type_ptr) *list)
1634 check_type_stack_depth ();
1635 type_stack.elements[type_stack.depth++].typelist_val = list;
1636 push_type (tp_function_with_arguments);
1639 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1640 as modified by all the stuff on the stack. */
1642 follow_types (struct type *follow_type)
1646 int make_volatile = 0;
1647 int make_addr_space = 0;
1651 switch (pop_type ())
1656 follow_type = make_cv_type (make_const,
1657 TYPE_VOLATILE (follow_type),
1660 follow_type = make_cv_type (TYPE_CONST (follow_type),
1663 if (make_addr_space)
1664 follow_type = make_type_with_address_space (follow_type,
1666 make_const = make_volatile = 0;
1667 make_addr_space = 0;
1675 case tp_space_identifier:
1676 make_addr_space = pop_type_int ();
1679 follow_type = lookup_pointer_type (follow_type);
1681 follow_type = make_cv_type (make_const,
1682 TYPE_VOLATILE (follow_type),
1685 follow_type = make_cv_type (TYPE_CONST (follow_type),
1688 if (make_addr_space)
1689 follow_type = make_type_with_address_space (follow_type,
1691 make_const = make_volatile = 0;
1692 make_addr_space = 0;
1695 follow_type = lookup_lvalue_reference_type (follow_type);
1696 goto process_reference;
1697 case tp_rvalue_reference:
1698 follow_type = lookup_rvalue_reference_type (follow_type);
1701 follow_type = make_cv_type (make_const,
1702 TYPE_VOLATILE (follow_type),
1705 follow_type = make_cv_type (TYPE_CONST (follow_type),
1708 if (make_addr_space)
1709 follow_type = make_type_with_address_space (follow_type,
1711 make_const = make_volatile = 0;
1712 make_addr_space = 0;
1715 array_size = pop_type_int ();
1716 /* FIXME-type-allocation: need a way to free this type when we are
1719 lookup_array_range_type (follow_type,
1720 0, array_size >= 0 ? array_size - 1 : 0);
1722 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type))
1726 /* FIXME-type-allocation: need a way to free this type when we are
1728 follow_type = lookup_function_type (follow_type);
1731 case tp_function_with_arguments:
1733 VEC (type_ptr) *args = pop_typelist ();
1736 = lookup_function_type_with_arguments (follow_type,
1737 VEC_length (type_ptr, args),
1738 VEC_address (type_ptr,
1740 VEC_free (type_ptr, args);
1746 struct type_stack *stack = pop_type_stack ();
1747 /* Sort of ugly, but not really much worse than the
1749 struct type_stack save = type_stack;
1751 type_stack = *stack;
1752 follow_type = follow_types (follow_type);
1753 gdb_assert (type_stack.depth == 0);
1759 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1764 /* This function avoids direct calls to fprintf
1765 in the parser generated debug code. */
1767 parser_fprintf (FILE *x, const char *y, ...)
1773 vfprintf_unfiltered (gdb_stderr, y, args);
1776 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1777 vfprintf_unfiltered (gdb_stderr, y, args);
1782 /* Implementation of the exp_descriptor method operator_check. */
1785 operator_check_standard (struct expression *exp, int pos,
1786 int (*objfile_func) (struct objfile *objfile,
1790 const union exp_element *const elts = exp->elts;
1791 struct type *type = NULL;
1792 struct objfile *objfile = NULL;
1794 /* Extended operators should have been already handled by exp_descriptor
1795 iterate method of its specific language. */
1796 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1798 /* Track the callers of write_exp_elt_type for this table. */
1800 switch (elts[pos].opcode)
1813 type = elts[pos + 1].type;
1818 LONGEST arg, nargs = elts[pos + 1].longconst;
1820 for (arg = 0; arg < nargs; arg++)
1822 struct type *type = elts[pos + 2 + arg].type;
1823 struct objfile *objfile = TYPE_OBJFILE (type);
1825 if (objfile && (*objfile_func) (objfile, data))
1833 const struct block *const block = elts[pos + 1].block;
1834 const struct symbol *const symbol = elts[pos + 2].symbol;
1836 /* Check objfile where the variable itself is placed.
1837 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1838 if ((*objfile_func) (symbol_objfile (symbol), data))
1841 /* Check objfile where is placed the code touching the variable. */
1842 objfile = lookup_objfile_from_block (block);
1844 type = SYMBOL_TYPE (symbol);
1847 case OP_VAR_MSYM_VALUE:
1848 objfile = elts[pos + 1].objfile;
1852 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1854 if (type && TYPE_OBJFILE (type)
1855 && (*objfile_func) (TYPE_OBJFILE (type), data))
1857 if (objfile && (*objfile_func) (objfile, data))
1863 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1864 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1865 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1866 returns non-zero value then (any other) non-zero value is immediately
1867 returned to the caller. Otherwise zero is returned after iterating
1868 through whole EXP. */
1871 exp_iterate (struct expression *exp,
1872 int (*objfile_func) (struct objfile *objfile, void *data),
1877 for (endpos = exp->nelts; endpos > 0; )
1879 int pos, args, oplen = 0;
1881 operator_length (exp, endpos, &oplen, &args);
1882 gdb_assert (oplen > 0);
1884 pos = endpos - oplen;
1885 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1886 objfile_func, data))
1895 /* Helper for exp_uses_objfile. */
1898 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1900 struct objfile *objfile = (struct objfile *) objfile_voidp;
1902 if (exp_objfile->separate_debug_objfile_backlink)
1903 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1905 return exp_objfile == objfile;
1908 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1909 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1913 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1915 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1917 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1920 /* See definition in parser-defs.h. */
1923 increase_expout_size (struct parser_state *ps, size_t lenelt)
1925 if ((ps->expout_ptr + lenelt) >= ps->expout_size)
1927 ps->expout_size = std::max (ps->expout_size * 2,
1928 ps->expout_ptr + lenelt + 10);
1929 ps->expout = (struct expression *)
1930 xrealloc (ps->expout, (sizeof (struct expression)
1931 + EXP_ELEM_TO_BYTES (ps->expout_size)));
1936 _initialize_parse (void)
1938 type_stack.size = 0;
1939 type_stack.depth = 0;
1940 type_stack.elements = NULL;
1942 add_setshow_zuinteger_cmd ("expression", class_maintenance,
1944 _("Set expression debugging."),
1945 _("Show expression debugging."),
1946 _("When non-zero, the internal representation "
1947 "of expressions will be printed."),
1949 show_expressiondebug,
1950 &setdebuglist, &showdebuglist);
1951 add_setshow_boolean_cmd ("parser", class_maintenance,
1953 _("Set parser debugging."),
1954 _("Show parser debugging."),
1955 _("When non-zero, expression parser "
1956 "tracing will be enabled."),
1959 &setdebuglist, &showdebuglist);