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:
953 case UNOP_MEMVAL_TLS:
974 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
975 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
980 case STRUCTOP_STRUCT:
987 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
988 NSString constant. */
989 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
991 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
992 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
997 args = longest_to_int (expr->elts[endpos - 2].longconst);
998 args -= longest_to_int (expr->elts[endpos - 3].longconst);
1008 case MULTI_SUBSCRIPT:
1010 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
1013 case BINOP_ASSIGN_MODIFY:
1025 range_type = (enum range_type)
1026 longest_to_int (expr->elts[endpos - 2].longconst);
1030 case LOW_BOUND_DEFAULT:
1031 case HIGH_BOUND_DEFAULT:
1034 case BOTH_BOUND_DEFAULT:
1037 case NONE_BOUND_DEFAULT:
1045 args = 1 + (i < (int) BINOP_END);
1052 /* Copy the subexpression ending just before index INEND in INEXPR
1053 into OUTEXPR, starting at index OUTBEG.
1054 In the process, convert it from suffix to prefix form.
1055 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1056 Otherwise, it returns the index of the subexpression which is the
1057 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1060 prefixify_subexp (struct expression *inexpr,
1061 struct expression *outexpr, int inend, int outbeg)
1069 operator_length (inexpr, inend, &oplen, &args);
1071 /* Copy the final operator itself, from the end of the input
1072 to the beginning of the output. */
1074 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1075 EXP_ELEM_TO_BYTES (oplen));
1078 if (expout_last_struct == inend)
1079 result = outbeg - oplen;
1081 /* Find the lengths of the arg subexpressions. */
1082 arglens = (int *) alloca (args * sizeof (int));
1083 for (i = args - 1; i >= 0; i--)
1085 oplen = length_of_subexp (inexpr, inend);
1090 /* Now copy each subexpression, preserving the order of
1091 the subexpressions, but prefixifying each one.
1092 In this loop, inend starts at the beginning of
1093 the expression this level is working on
1094 and marches forward over the arguments.
1095 outbeg does similarly in the output. */
1096 for (i = 0; i < args; i++)
1102 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1105 /* Return immediately. We probably have only parsed a
1106 partial expression, so we don't want to try to reverse
1107 the other operands. */
1116 /* Read an expression from the string *STRINGPTR points to,
1117 parse it, and return a pointer to a struct expression that we malloc.
1118 Use block BLOCK as the lexical context for variable names;
1119 if BLOCK is zero, use the block of the selected stack frame.
1120 Meanwhile, advance *STRINGPTR to point after the expression,
1121 at the first nonwhite character that is not part of the expression
1122 (possibly a null character).
1124 If COMMA is nonzero, stop if a comma is reached. */
1127 parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
1130 return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL);
1133 static expression_up
1134 parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
1135 const struct block *block,
1136 int comma, int void_context_p, int *out_subexp)
1138 return parse_exp_in_context_1 (stringptr, pc, block, comma,
1139 void_context_p, out_subexp);
1142 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1143 no value is expected from the expression.
1144 OUT_SUBEXP is set when attempting to complete a field name; in this
1145 case it is set to the index of the subexpression on the
1146 left-hand-side of the struct op. If not doing such completion, it
1147 is left untouched. */
1149 static expression_up
1150 parse_exp_in_context_1 (const char **stringptr, CORE_ADDR pc,
1151 const struct block *block,
1152 int comma, int void_context_p, int *out_subexp)
1154 struct cleanup *old_chain;
1155 const struct language_defn *lang = NULL;
1156 struct parser_state ps;
1159 lexptr = *stringptr;
1163 type_stack.depth = 0;
1164 expout_last_struct = -1;
1165 expout_tag_completion_type = TYPE_CODE_UNDEF;
1166 xfree (expout_completion_name);
1167 expout_completion_name = NULL;
1169 comma_terminates = comma;
1171 if (lexptr == 0 || *lexptr == 0)
1172 error_no_arg (_("expression to compute"));
1174 old_chain = make_cleanup (free_funcalls, 0 /*ignore*/);
1177 expression_context_block = block;
1179 /* If no context specified, try using the current frame, if any. */
1180 if (!expression_context_block)
1181 expression_context_block = get_selected_block (&expression_context_pc);
1183 expression_context_pc = BLOCK_START (expression_context_block);
1185 expression_context_pc = pc;
1187 /* Fall back to using the current source static context, if any. */
1189 if (!expression_context_block)
1191 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1193 expression_context_block
1194 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
1196 if (expression_context_block)
1197 expression_context_pc = BLOCK_START (expression_context_block);
1200 if (language_mode == language_mode_auto && block != NULL)
1202 /* Find the language associated to the given context block.
1203 Default to the current language if it can not be determined.
1205 Note that using the language corresponding to the current frame
1206 can sometimes give unexpected results. For instance, this
1207 routine is often called several times during the inferior
1208 startup phase to re-parse breakpoint expressions after
1209 a new shared library has been loaded. The language associated
1210 to the current frame at this moment is not relevant for
1211 the breakpoint. Using it would therefore be silly, so it seems
1212 better to rely on the current language rather than relying on
1213 the current frame language to parse the expression. That's why
1214 we do the following language detection only if the context block
1215 has been specifically provided. */
1216 struct symbol *func = block_linkage_function (block);
1219 lang = language_def (SYMBOL_LANGUAGE (func));
1220 if (lang == NULL || lang->la_language == language_unknown)
1221 lang = current_language;
1224 lang = current_language;
1226 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1227 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1228 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1229 to the value matching SELECTED_FRAME as set by get_current_arch. */
1231 initialize_expout (&ps, 10, lang, get_current_arch ());
1233 scoped_restore_current_language lang_saver;
1234 set_language (lang->la_language);
1238 if (lang->la_parser (&ps))
1239 lang->la_error (NULL);
1241 CATCH (except, RETURN_MASK_ALL)
1243 if (! parse_completion)
1246 throw_exception (except);
1251 reallocate_expout (&ps);
1253 /* Convert expression from postfix form as generated by yacc
1254 parser, to a prefix form. */
1256 if (expressiondebug)
1257 dump_raw_expression (ps.expout, gdb_stdlog,
1258 "before conversion to prefix form");
1260 subexp = prefixify_expression (ps.expout);
1262 *out_subexp = subexp;
1264 lang->la_post_parser (&ps.expout, void_context_p);
1266 if (expressiondebug)
1267 dump_prefix_expression (ps.expout, gdb_stdlog);
1269 discard_cleanups (old_chain);
1271 *stringptr = lexptr;
1272 return expression_up (ps.expout);
1275 /* Parse STRING as an expression, and complain if this fails
1276 to use up all of the contents of STRING. */
1279 parse_expression (const char *string)
1281 expression_up exp = parse_exp_1 (&string, 0, 0, 0);
1283 error (_("Junk after end of expression."));
1287 /* Same as parse_expression, but using the given language (LANG)
1288 to parse the expression. */
1291 parse_expression_with_language (const char *string, enum language lang)
1293 gdb::optional<scoped_restore_current_language> lang_saver;
1294 if (current_language->la_language != lang)
1296 lang_saver.emplace ();
1297 set_language (lang);
1300 return parse_expression (string);
1303 /* Parse STRING as an expression. If parsing ends in the middle of a
1304 field reference, return the type of the left-hand-side of the
1305 reference; furthermore, if the parsing ends in the field name,
1306 return the field name in *NAME. If the parsing ends in the middle
1307 of a field reference, but the reference is somehow invalid, throw
1308 an exception. In all other cases, return NULL. Returned non-NULL
1309 *NAME must be freed by the caller. */
1312 parse_expression_for_completion (const char *string, char **name,
1313 enum type_code *code)
1321 parse_completion = 1;
1322 exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp);
1324 CATCH (except, RETURN_MASK_ERROR)
1326 /* Nothing, EXP remains NULL. */
1330 parse_completion = 0;
1334 if (expout_tag_completion_type != TYPE_CODE_UNDEF)
1336 *code = expout_tag_completion_type;
1337 *name = expout_completion_name;
1338 expout_completion_name = NULL;
1342 if (expout_last_struct == -1)
1345 *name = extract_field_op (exp.get (), &subexp);
1349 /* This might throw an exception. If so, we want to let it
1351 val = evaluate_subexpression_type (exp.get (), subexp);
1352 /* (*NAME) is a part of the EXP memory block freed below. */
1353 *name = xstrdup (*name);
1355 return value_type (val);
1358 /* A post-parser that does nothing. */
1361 null_post_parser (struct expression **exp, int void_context_p)
1365 /* Parse floating point value P of length LEN.
1366 Return 0 (false) if invalid, 1 (true) if valid.
1367 The successfully parsed number is stored in D.
1368 *SUFFIX points to the suffix of the number in P.
1370 NOTE: This accepts the floating point syntax that sscanf accepts. */
1373 parse_float (const char *p, int len, DOUBLEST *d, const char **suffix)
1378 copy = (char *) xmalloc (len + 1);
1379 memcpy (copy, p, len);
1382 num = sscanf (copy, "%" DOUBLEST_SCAN_FORMAT "%n", d, &n);
1385 /* The sscanf man page suggests not making any assumptions on the effect
1386 of %n on the result, so we don't.
1387 That is why we simply test num == 0. */
1395 /* Parse floating point value P of length LEN, using the C syntax for floats.
1396 Return 0 (false) if invalid, 1 (true) if valid.
1397 The successfully parsed number is stored in *D.
1398 Its type is taken from builtin_type (gdbarch) and is stored in *T. */
1401 parse_c_float (struct gdbarch *gdbarch, const char *p, int len,
1402 DOUBLEST *d, struct type **t)
1406 const struct builtin_type *builtin_types = builtin_type (gdbarch);
1408 if (! parse_float (p, len, d, &suffix))
1411 suffix_len = p + len - suffix;
1413 if (suffix_len == 0)
1414 *t = builtin_types->builtin_double;
1415 else if (suffix_len == 1)
1417 /* Handle suffixes: 'f' for float, 'l' for long double. */
1418 if (tolower (*suffix) == 'f')
1419 *t = builtin_types->builtin_float;
1420 else if (tolower (*suffix) == 'l')
1421 *t = builtin_types->builtin_long_double;
1431 /* Stuff for maintaining a stack of types. Currently just used by C, but
1432 probably useful for any language which declares its types "backwards". */
1434 /* Ensure that there are HOWMUCH open slots on the type stack STACK. */
1437 type_stack_reserve (struct type_stack *stack, int howmuch)
1439 if (stack->depth + howmuch >= stack->size)
1442 if (stack->size < howmuch)
1443 stack->size = howmuch;
1444 stack->elements = XRESIZEVEC (union type_stack_elt, stack->elements,
1449 /* Ensure that there is a single open slot in the global type stack. */
1452 check_type_stack_depth (void)
1454 type_stack_reserve (&type_stack, 1);
1457 /* A helper function for insert_type and insert_type_address_space.
1458 This does work of expanding the type stack and inserting the new
1459 element, ELEMENT, into the stack at location SLOT. */
1462 insert_into_type_stack (int slot, union type_stack_elt element)
1464 check_type_stack_depth ();
1466 if (slot < type_stack.depth)
1467 memmove (&type_stack.elements[slot + 1], &type_stack.elements[slot],
1468 (type_stack.depth - slot) * sizeof (union type_stack_elt));
1469 type_stack.elements[slot] = element;
1473 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1474 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1475 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1476 previous tp_pointer) if there is anything on the stack, or simply pushed
1477 if the stack is empty. Other values for TP are invalid. */
1480 insert_type (enum type_pieces tp)
1482 union type_stack_elt element;
1485 gdb_assert (tp == tp_pointer || tp == tp_reference
1486 || tp == tp_rvalue_reference || tp == tp_const
1487 || tp == tp_volatile);
1489 /* If there is anything on the stack (we know it will be a
1490 tp_pointer), insert the qualifier above it. Otherwise, simply
1491 push this on the top of the stack. */
1492 if (type_stack.depth && (tp == tp_const || tp == tp_volatile))
1498 insert_into_type_stack (slot, element);
1502 push_type (enum type_pieces tp)
1504 check_type_stack_depth ();
1505 type_stack.elements[type_stack.depth++].piece = tp;
1509 push_type_int (int n)
1511 check_type_stack_depth ();
1512 type_stack.elements[type_stack.depth++].int_val = n;
1515 /* Insert a tp_space_identifier and the corresponding address space
1516 value into the stack. STRING is the name of an address space, as
1517 recognized by address_space_name_to_int. If the stack is empty,
1518 the new elements are simply pushed. If the stack is not empty,
1519 this function assumes that the first item on the stack is a
1520 tp_pointer, and the new values are inserted above the first
1524 insert_type_address_space (struct parser_state *pstate, char *string)
1526 union type_stack_elt element;
1529 /* If there is anything on the stack (we know it will be a
1530 tp_pointer), insert the address space qualifier above it.
1531 Otherwise, simply push this on the top of the stack. */
1532 if (type_stack.depth)
1537 element.piece = tp_space_identifier;
1538 insert_into_type_stack (slot, element);
1539 element.int_val = address_space_name_to_int (parse_gdbarch (pstate),
1541 insert_into_type_stack (slot, element);
1547 if (type_stack.depth)
1548 return type_stack.elements[--type_stack.depth].piece;
1555 if (type_stack.depth)
1556 return type_stack.elements[--type_stack.depth].int_val;
1557 /* "Can't happen". */
1561 /* Pop a type list element from the global type stack. */
1563 static VEC (type_ptr) *
1566 gdb_assert (type_stack.depth);
1567 return type_stack.elements[--type_stack.depth].typelist_val;
1570 /* Pop a type_stack element from the global type stack. */
1572 static struct type_stack *
1573 pop_type_stack (void)
1575 gdb_assert (type_stack.depth);
1576 return type_stack.elements[--type_stack.depth].stack_val;
1579 /* Append the elements of the type stack FROM to the type stack TO.
1580 Always returns TO. */
1583 append_type_stack (struct type_stack *to, struct type_stack *from)
1585 type_stack_reserve (to, from->depth);
1587 memcpy (&to->elements[to->depth], &from->elements[0],
1588 from->depth * sizeof (union type_stack_elt));
1589 to->depth += from->depth;
1594 /* Push the type stack STACK as an element on the global type stack. */
1597 push_type_stack (struct type_stack *stack)
1599 check_type_stack_depth ();
1600 type_stack.elements[type_stack.depth++].stack_val = stack;
1601 push_type (tp_type_stack);
1604 /* Copy the global type stack into a newly allocated type stack and
1605 return it. The global stack is cleared. The returned type stack
1606 must be freed with type_stack_cleanup. */
1609 get_type_stack (void)
1611 struct type_stack *result = XNEW (struct type_stack);
1613 *result = type_stack;
1614 type_stack.depth = 0;
1615 type_stack.size = 0;
1616 type_stack.elements = NULL;
1621 /* A cleanup function that destroys a single type stack. */
1624 type_stack_cleanup (void *arg)
1626 struct type_stack *stack = (struct type_stack *) arg;
1628 xfree (stack->elements);
1632 /* Push a function type with arguments onto the global type stack.
1633 LIST holds the argument types. If the final item in LIST is NULL,
1634 then the function will be varargs. */
1637 push_typelist (VEC (type_ptr) *list)
1639 check_type_stack_depth ();
1640 type_stack.elements[type_stack.depth++].typelist_val = list;
1641 push_type (tp_function_with_arguments);
1644 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1645 as modified by all the stuff on the stack. */
1647 follow_types (struct type *follow_type)
1651 int make_volatile = 0;
1652 int make_addr_space = 0;
1656 switch (pop_type ())
1661 follow_type = make_cv_type (make_const,
1662 TYPE_VOLATILE (follow_type),
1665 follow_type = make_cv_type (TYPE_CONST (follow_type),
1668 if (make_addr_space)
1669 follow_type = make_type_with_address_space (follow_type,
1671 make_const = make_volatile = 0;
1672 make_addr_space = 0;
1680 case tp_space_identifier:
1681 make_addr_space = pop_type_int ();
1684 follow_type = lookup_pointer_type (follow_type);
1686 follow_type = make_cv_type (make_const,
1687 TYPE_VOLATILE (follow_type),
1690 follow_type = make_cv_type (TYPE_CONST (follow_type),
1693 if (make_addr_space)
1694 follow_type = make_type_with_address_space (follow_type,
1696 make_const = make_volatile = 0;
1697 make_addr_space = 0;
1700 follow_type = lookup_lvalue_reference_type (follow_type);
1701 goto process_reference;
1702 case tp_rvalue_reference:
1703 follow_type = lookup_rvalue_reference_type (follow_type);
1706 follow_type = make_cv_type (make_const,
1707 TYPE_VOLATILE (follow_type),
1710 follow_type = make_cv_type (TYPE_CONST (follow_type),
1713 if (make_addr_space)
1714 follow_type = make_type_with_address_space (follow_type,
1716 make_const = make_volatile = 0;
1717 make_addr_space = 0;
1720 array_size = pop_type_int ();
1721 /* FIXME-type-allocation: need a way to free this type when we are
1724 lookup_array_range_type (follow_type,
1725 0, array_size >= 0 ? array_size - 1 : 0);
1727 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type))
1731 /* FIXME-type-allocation: need a way to free this type when we are
1733 follow_type = lookup_function_type (follow_type);
1736 case tp_function_with_arguments:
1738 VEC (type_ptr) *args = pop_typelist ();
1741 = lookup_function_type_with_arguments (follow_type,
1742 VEC_length (type_ptr, args),
1743 VEC_address (type_ptr,
1745 VEC_free (type_ptr, args);
1751 struct type_stack *stack = pop_type_stack ();
1752 /* Sort of ugly, but not really much worse than the
1754 struct type_stack save = type_stack;
1756 type_stack = *stack;
1757 follow_type = follow_types (follow_type);
1758 gdb_assert (type_stack.depth == 0);
1764 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1769 /* This function avoids direct calls to fprintf
1770 in the parser generated debug code. */
1772 parser_fprintf (FILE *x, const char *y, ...)
1778 vfprintf_unfiltered (gdb_stderr, y, args);
1781 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1782 vfprintf_unfiltered (gdb_stderr, y, args);
1787 /* Implementation of the exp_descriptor method operator_check. */
1790 operator_check_standard (struct expression *exp, int pos,
1791 int (*objfile_func) (struct objfile *objfile,
1795 const union exp_element *const elts = exp->elts;
1796 struct type *type = NULL;
1797 struct objfile *objfile = NULL;
1799 /* Extended operators should have been already handled by exp_descriptor
1800 iterate method of its specific language. */
1801 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1803 /* Track the callers of write_exp_elt_type for this table. */
1805 switch (elts[pos].opcode)
1818 type = elts[pos + 1].type;
1823 LONGEST arg, nargs = elts[pos + 1].longconst;
1825 for (arg = 0; arg < nargs; arg++)
1827 struct type *type = elts[pos + 2 + arg].type;
1828 struct objfile *objfile = TYPE_OBJFILE (type);
1830 if (objfile && (*objfile_func) (objfile, data))
1836 case UNOP_MEMVAL_TLS:
1837 objfile = elts[pos + 1].objfile;
1838 type = elts[pos + 2].type;
1843 const struct block *const block = elts[pos + 1].block;
1844 const struct symbol *const symbol = elts[pos + 2].symbol;
1846 /* Check objfile where the variable itself is placed.
1847 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1848 if ((*objfile_func) (symbol_objfile (symbol), data))
1851 /* Check objfile where is placed the code touching the variable. */
1852 objfile = lookup_objfile_from_block (block);
1854 type = SYMBOL_TYPE (symbol);
1857 case OP_VAR_MSYM_VALUE:
1858 objfile = elts[pos + 1].objfile;
1862 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1864 if (type && TYPE_OBJFILE (type)
1865 && (*objfile_func) (TYPE_OBJFILE (type), data))
1867 if (objfile && (*objfile_func) (objfile, data))
1873 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1874 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1875 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1876 returns non-zero value then (any other) non-zero value is immediately
1877 returned to the caller. Otherwise zero is returned after iterating
1878 through whole EXP. */
1881 exp_iterate (struct expression *exp,
1882 int (*objfile_func) (struct objfile *objfile, void *data),
1887 for (endpos = exp->nelts; endpos > 0; )
1889 int pos, args, oplen = 0;
1891 operator_length (exp, endpos, &oplen, &args);
1892 gdb_assert (oplen > 0);
1894 pos = endpos - oplen;
1895 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1896 objfile_func, data))
1905 /* Helper for exp_uses_objfile. */
1908 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1910 struct objfile *objfile = (struct objfile *) objfile_voidp;
1912 if (exp_objfile->separate_debug_objfile_backlink)
1913 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1915 return exp_objfile == objfile;
1918 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1919 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1923 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1925 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1927 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1930 /* See definition in parser-defs.h. */
1933 increase_expout_size (struct parser_state *ps, size_t lenelt)
1935 if ((ps->expout_ptr + lenelt) >= ps->expout_size)
1937 ps->expout_size = std::max (ps->expout_size * 2,
1938 ps->expout_ptr + lenelt + 10);
1939 ps->expout = (struct expression *)
1940 xrealloc (ps->expout, (sizeof (struct expression)
1941 + EXP_ELEM_TO_BYTES (ps->expout_size)));
1946 _initialize_parse (void)
1948 type_stack.size = 0;
1949 type_stack.depth = 0;
1950 type_stack.elements = NULL;
1952 add_setshow_zuinteger_cmd ("expression", class_maintenance,
1954 _("Set expression debugging."),
1955 _("Show expression debugging."),
1956 _("When non-zero, the internal representation "
1957 "of expressions will be printed."),
1959 show_expressiondebug,
1960 &setdebuglist, &showdebuglist);
1961 add_setshow_boolean_cmd ("parser", class_maintenance,
1963 _("Set parser debugging."),
1964 _("Show parser debugging."),
1965 _("When non-zero, expression parser "
1966 "tracing will be enabled."),
1969 &setdebuglist, &showdebuglist);