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 */
47 #include "target-float.h"
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 int prefixify_subexp (struct expression *, struct expression *, int,
117 static expression_up parse_exp_in_context (const char **, CORE_ADDR,
118 const struct block *, int,
120 static expression_up parse_exp_in_context_1 (const char **, CORE_ADDR,
121 const struct block *, int,
124 /* Data structure for saving values of arglist_len for function calls whose
125 arguments contain other function calls. */
127 static std::vector<int> *funcall_chain;
129 /* Begin counting arguments for a function call,
130 saving the data about any containing call. */
135 funcall_chain->push_back (arglist_len);
139 /* Return the number of arguments in a function call just terminated,
140 and restore the data for the containing function call. */
145 int val = arglist_len;
146 arglist_len = funcall_chain->back ();
147 funcall_chain->pop_back ();
153 /* See definition in parser-defs.h. */
156 initialize_expout (struct parser_state *ps, size_t initial_size,
157 const struct language_defn *lang,
158 struct gdbarch *gdbarch)
160 ps->expout_size = initial_size;
163 = (struct expression *) xmalloc (sizeof (struct expression)
164 + EXP_ELEM_TO_BYTES (ps->expout_size));
165 ps->expout->language_defn = lang;
166 ps->expout->gdbarch = gdbarch;
169 /* See definition in parser-defs.h. */
172 reallocate_expout (struct parser_state *ps)
174 /* Record the actual number of expression elements, and then
175 reallocate the expression memory so that we free up any
178 ps->expout->nelts = ps->expout_ptr;
179 ps->expout = (struct expression *)
180 xrealloc (ps->expout,
181 sizeof (struct expression)
182 + EXP_ELEM_TO_BYTES (ps->expout_ptr));
185 /* This page contains the functions for adding data to the struct expression
186 being constructed. */
188 /* Add one element to the end of the expression. */
190 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
191 a register through here. */
194 write_exp_elt (struct parser_state *ps, const union exp_element *expelt)
196 if (ps->expout_ptr >= ps->expout_size)
198 ps->expout_size *= 2;
199 ps->expout = (struct expression *)
200 xrealloc (ps->expout, sizeof (struct expression)
201 + EXP_ELEM_TO_BYTES (ps->expout_size));
203 ps->expout->elts[ps->expout_ptr++] = *expelt;
207 write_exp_elt_opcode (struct parser_state *ps, enum exp_opcode expelt)
209 union exp_element tmp;
211 memset (&tmp, 0, sizeof (union exp_element));
213 write_exp_elt (ps, &tmp);
217 write_exp_elt_sym (struct parser_state *ps, struct symbol *expelt)
219 union exp_element tmp;
221 memset (&tmp, 0, sizeof (union exp_element));
223 write_exp_elt (ps, &tmp);
227 write_exp_elt_msym (struct parser_state *ps, minimal_symbol *expelt)
229 union exp_element tmp;
231 memset (&tmp, 0, sizeof (union exp_element));
232 tmp.msymbol = expelt;
233 write_exp_elt (ps, &tmp);
237 write_exp_elt_block (struct parser_state *ps, const struct block *b)
239 union exp_element tmp;
241 memset (&tmp, 0, sizeof (union exp_element));
243 write_exp_elt (ps, &tmp);
247 write_exp_elt_objfile (struct parser_state *ps, struct objfile *objfile)
249 union exp_element tmp;
251 memset (&tmp, 0, sizeof (union exp_element));
252 tmp.objfile = objfile;
253 write_exp_elt (ps, &tmp);
257 write_exp_elt_longcst (struct parser_state *ps, LONGEST expelt)
259 union exp_element tmp;
261 memset (&tmp, 0, sizeof (union exp_element));
262 tmp.longconst = expelt;
263 write_exp_elt (ps, &tmp);
267 write_exp_elt_floatcst (struct parser_state *ps, const gdb_byte expelt[16])
269 union exp_element tmp;
272 for (index = 0; index < 16; index++)
273 tmp.floatconst[index] = expelt[index];
275 write_exp_elt (ps, &tmp);
279 write_exp_elt_type (struct parser_state *ps, struct type *expelt)
281 union exp_element tmp;
283 memset (&tmp, 0, sizeof (union exp_element));
285 write_exp_elt (ps, &tmp);
289 write_exp_elt_intern (struct parser_state *ps, struct internalvar *expelt)
291 union exp_element tmp;
293 memset (&tmp, 0, sizeof (union exp_element));
294 tmp.internalvar = expelt;
295 write_exp_elt (ps, &tmp);
298 /* Add a string constant to the end of the expression.
300 String constants are stored by first writing an expression element
301 that contains the length of the string, then stuffing the string
302 constant itself into however many expression elements are needed
303 to hold it, and then writing another expression element that contains
304 the length of the string. I.e. an expression element at each end of
305 the string records the string length, so you can skip over the
306 expression elements containing the actual string bytes from either
307 end of the string. Note that this also allows gdb to handle
308 strings with embedded null bytes, as is required for some languages.
310 Don't be fooled by the fact that the string is null byte terminated,
311 this is strictly for the convenience of debugging gdb itself.
312 Gdb does not depend up the string being null terminated, since the
313 actual length is recorded in expression elements at each end of the
314 string. The null byte is taken into consideration when computing how
315 many expression elements are required to hold the string constant, of
320 write_exp_string (struct parser_state *ps, struct stoken str)
322 int len = str.length;
326 /* Compute the number of expression elements required to hold the string
327 (including a null byte terminator), along with one expression element
328 at each end to record the actual string length (not including the
329 null byte terminator). */
331 lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);
333 increase_expout_size (ps, lenelt);
335 /* Write the leading length expression element (which advances the current
336 expression element index), then write the string constant followed by a
337 terminating null byte, and then write the trailing length expression
340 write_exp_elt_longcst (ps, (LONGEST) len);
341 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
342 memcpy (strdata, str.ptr, len);
343 *(strdata + len) = '\0';
344 ps->expout_ptr += lenelt - 2;
345 write_exp_elt_longcst (ps, (LONGEST) len);
348 /* Add a vector of string constants to the end of the expression.
350 This adds an OP_STRING operation, but encodes the contents
351 differently from write_exp_string. The language is expected to
352 handle evaluation of this expression itself.
354 After the usual OP_STRING header, TYPE is written into the
355 expression as a long constant. The interpretation of this field is
356 up to the language evaluator.
358 Next, each string in VEC is written. The length is written as a
359 long constant, followed by the contents of the string. */
362 write_exp_string_vector (struct parser_state *ps, int type,
363 struct stoken_vector *vec)
368 /* Compute the size. We compute the size in number of slots to
369 avoid issues with string padding. */
371 for (i = 0; i < vec->len; ++i)
373 /* One slot for the length of this element, plus the number of
374 slots needed for this string. */
375 n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
378 /* One more slot for the type of the string. */
381 /* Now compute a phony string length. */
382 len = EXP_ELEM_TO_BYTES (n_slots) - 1;
385 increase_expout_size (ps, n_slots);
387 write_exp_elt_opcode (ps, OP_STRING);
388 write_exp_elt_longcst (ps, len);
389 write_exp_elt_longcst (ps, type);
391 for (i = 0; i < vec->len; ++i)
393 write_exp_elt_longcst (ps, vec->tokens[i].length);
394 memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr,
395 vec->tokens[i].length);
396 ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
399 write_exp_elt_longcst (ps, len);
400 write_exp_elt_opcode (ps, OP_STRING);
403 /* Add a bitstring constant to the end of the expression.
405 Bitstring constants are stored by first writing an expression element
406 that contains the length of the bitstring (in bits), then stuffing the
407 bitstring constant itself into however many expression elements are
408 needed to hold it, and then writing another expression element that
409 contains the length of the bitstring. I.e. an expression element at
410 each end of the bitstring records the bitstring length, so you can skip
411 over the expression elements containing the actual bitstring bytes from
412 either end of the bitstring. */
415 write_exp_bitstring (struct parser_state *ps, struct stoken str)
417 int bits = str.length; /* length in bits */
418 int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
422 /* Compute the number of expression elements required to hold the bitstring,
423 along with one expression element at each end to record the actual
424 bitstring length in bits. */
426 lenelt = 2 + BYTES_TO_EXP_ELEM (len);
428 increase_expout_size (ps, lenelt);
430 /* Write the leading length expression element (which advances the current
431 expression element index), then write the bitstring constant, and then
432 write the trailing length expression element. */
434 write_exp_elt_longcst (ps, (LONGEST) bits);
435 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
436 memcpy (strdata, str.ptr, len);
437 ps->expout_ptr += lenelt - 2;
438 write_exp_elt_longcst (ps, (LONGEST) bits);
441 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
442 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
446 find_minsym_type_and_address (minimal_symbol *msymbol,
447 struct objfile *objfile,
448 CORE_ADDR *address_p)
450 bound_minimal_symbol bound_msym = {msymbol, objfile};
451 struct gdbarch *gdbarch = get_objfile_arch (objfile);
452 struct obj_section *section = MSYMBOL_OBJ_SECTION (objfile, msymbol);
453 enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
456 bool is_tls = (section != NULL
457 && section->the_bfd_section->flags & SEC_THREAD_LOCAL);
459 /* Addresses of TLS symbols are really offsets into a
460 per-objfile/per-thread storage block. */
461 CORE_ADDR addr = (is_tls
462 ? MSYMBOL_VALUE_RAW_ADDRESS (bound_msym.minsym)
463 : BMSYMBOL_VALUE_ADDRESS (bound_msym));
465 /* The minimal symbol might point to a function descriptor;
466 resolve it to the actual code address instead. */
467 pc = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, ¤t_target);
470 struct bound_minimal_symbol ifunc_msym = lookup_minimal_symbol_by_pc (pc);
472 /* In this case, assume we have a code symbol instead of
475 if (ifunc_msym.minsym != NULL
476 && MSYMBOL_TYPE (ifunc_msym.minsym) == mst_text_gnu_ifunc
477 && BMSYMBOL_VALUE_ADDRESS (ifunc_msym) == pc)
479 /* A function descriptor has been resolved but PC is still in the
480 STT_GNU_IFUNC resolver body (such as because inferior does not
481 run to be able to call it). */
483 type = mst_text_gnu_ifunc;
491 if (overlay_debugging)
492 addr = symbol_overlayed_address (addr, section);
496 /* Skip translation if caller does not need the address. */
497 if (address_p != NULL)
498 *address_p = target_translate_tls_address (objfile, addr);
499 return objfile_type (objfile)->nodebug_tls_symbol;
502 if (address_p != NULL)
509 case mst_solib_trampoline:
510 return objfile_type (objfile)->nodebug_text_symbol;
512 case mst_text_gnu_ifunc:
513 return objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
519 return objfile_type (objfile)->nodebug_data_symbol;
521 case mst_slot_got_plt:
522 return objfile_type (objfile)->nodebug_got_plt_symbol;
525 return objfile_type (objfile)->nodebug_unknown_symbol;
529 /* Add the appropriate elements for a minimal symbol to the end of
533 write_exp_msymbol (struct parser_state *ps,
534 struct bound_minimal_symbol bound_msym)
536 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
537 write_exp_elt_objfile (ps, bound_msym.objfile);
538 write_exp_elt_msym (ps, bound_msym.minsym);
539 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
542 /* Mark the current index as the starting location of a structure
543 expression. This is used when completing on field names. */
546 mark_struct_expression (struct parser_state *ps)
548 gdb_assert (parse_completion
549 && expout_tag_completion_type == TYPE_CODE_UNDEF);
550 expout_last_struct = ps->expout_ptr;
553 /* Indicate that the current parser invocation is completing a tag.
554 TAG is the type code of the tag, and PTR and LENGTH represent the
555 start of the tag name. */
558 mark_completion_tag (enum type_code tag, const char *ptr, int length)
560 gdb_assert (parse_completion
561 && expout_tag_completion_type == TYPE_CODE_UNDEF
562 && expout_completion_name == NULL
563 && expout_last_struct == -1);
564 gdb_assert (tag == TYPE_CODE_UNION
565 || tag == TYPE_CODE_STRUCT
566 || tag == TYPE_CODE_ENUM);
567 expout_tag_completion_type = tag;
568 expout_completion_name = (char *) xmalloc (length + 1);
569 memcpy (expout_completion_name, ptr, length);
570 expout_completion_name[length] = '\0';
574 /* Recognize tokens that start with '$'. These include:
576 $regname A native register name or a "standard
579 $variable A convenience variable with a name chosen
582 $digits Value history with index <digits>, starting
583 from the first value which has index 1.
585 $$digits Value history with index <digits> relative
586 to the last value. I.e. $$0 is the last
587 value, $$1 is the one previous to that, $$2
588 is the one previous to $$1, etc.
590 $ | $0 | $$0 The last value in the value history.
592 $$ An abbreviation for the second to the last
593 value in the value history, I.e. $$1 */
596 write_dollar_variable (struct parser_state *ps, struct stoken str)
598 struct block_symbol sym;
599 struct bound_minimal_symbol msym;
600 struct internalvar *isym = NULL;
602 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
603 and $$digits (equivalent to $<-digits> if you could type that). */
607 /* Double dollar means negate the number and add -1 as well.
608 Thus $$ alone means -1. */
609 if (str.length >= 2 && str.ptr[1] == '$')
616 /* Just dollars (one or two). */
620 /* Is the rest of the token digits? */
621 for (; i < str.length; i++)
622 if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
626 i = atoi (str.ptr + 1 + negate);
632 /* Handle tokens that refer to machine registers:
633 $ followed by a register name. */
634 i = user_reg_map_name_to_regnum (parse_gdbarch (ps),
635 str.ptr + 1, str.length - 1);
637 goto handle_register;
639 /* Any names starting with $ are probably debugger internal variables. */
641 isym = lookup_only_internalvar (copy_name (str) + 1);
644 write_exp_elt_opcode (ps, OP_INTERNALVAR);
645 write_exp_elt_intern (ps, isym);
646 write_exp_elt_opcode (ps, OP_INTERNALVAR);
650 /* On some systems, such as HP-UX and hppa-linux, certain system routines
651 have names beginning with $ or $$. Check for those, first. */
653 sym = lookup_symbol (copy_name (str), (struct block *) NULL,
657 write_exp_elt_opcode (ps, OP_VAR_VALUE);
658 write_exp_elt_block (ps, sym.block);
659 write_exp_elt_sym (ps, sym.symbol);
660 write_exp_elt_opcode (ps, OP_VAR_VALUE);
663 msym = lookup_bound_minimal_symbol (copy_name (str));
666 write_exp_msymbol (ps, msym);
670 /* Any other names are assumed to be debugger internal variables. */
672 write_exp_elt_opcode (ps, OP_INTERNALVAR);
673 write_exp_elt_intern (ps, create_internalvar (copy_name (str) + 1));
674 write_exp_elt_opcode (ps, OP_INTERNALVAR);
677 write_exp_elt_opcode (ps, OP_LAST);
678 write_exp_elt_longcst (ps, (LONGEST) i);
679 write_exp_elt_opcode (ps, OP_LAST);
682 write_exp_elt_opcode (ps, OP_REGISTER);
685 write_exp_string (ps, str);
686 write_exp_elt_opcode (ps, OP_REGISTER);
692 find_template_name_end (const char *p)
695 int just_seen_right = 0;
696 int just_seen_colon = 0;
697 int just_seen_space = 0;
699 if (!p || (*p != '<'))
710 /* In future, may want to allow these?? */
713 depth++; /* start nested template */
714 if (just_seen_colon || just_seen_right || just_seen_space)
715 return 0; /* but not after : or :: or > or space */
718 if (just_seen_colon || just_seen_right)
719 return 0; /* end a (nested?) template */
720 just_seen_right = 1; /* but not after : or :: */
721 if (--depth == 0) /* also disallow >>, insist on > > */
722 return ++p; /* if outermost ended, return */
725 if (just_seen_space || (just_seen_colon > 1))
726 return 0; /* nested class spec coming up */
727 just_seen_colon++; /* we allow :: but not :::: */
732 if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
733 (*p >= 'A' && *p <= 'Z') ||
734 (*p >= '0' && *p <= '9') ||
735 (*p == '_') || (*p == ',') || /* commas for template args */
736 (*p == '&') || (*p == '*') || /* pointer and ref types */
737 (*p == '(') || (*p == ')') || /* function types */
738 (*p == '[') || (*p == ']'))) /* array types */
752 /* Return a null-terminated temporary copy of the name of a string token.
754 Tokens that refer to names do so with explicit pointer and length,
755 so they can share the storage that lexptr is parsing.
756 When it is necessary to pass a name to a function that expects
757 a null-terminated string, the substring is copied out
758 into a separate block of storage.
760 N.B. A single buffer is reused on each call. */
763 copy_name (struct stoken token)
765 /* A temporary buffer for identifiers, so we can null-terminate them.
766 We allocate this with xrealloc. parse_exp_1 used to allocate with
767 alloca, using the size of the whole expression as a conservative
768 estimate of the space needed. However, macro expansion can
769 introduce names longer than the original expression; there's no
770 practical way to know beforehand how large that might be. */
771 static char *namecopy;
772 static size_t namecopy_size;
774 /* Make sure there's enough space for the token. */
775 if (namecopy_size < token.length + 1)
777 namecopy_size = token.length + 1;
778 namecopy = (char *) xrealloc (namecopy, token.length + 1);
781 memcpy (namecopy, token.ptr, token.length);
782 namecopy[token.length] = 0;
788 /* See comments on parser-defs.h. */
791 prefixify_expression (struct expression *expr)
793 int len = sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts);
794 struct expression *temp;
795 int inpos = expr->nelts, outpos = 0;
797 temp = (struct expression *) alloca (len);
799 /* Copy the original expression into temp. */
800 memcpy (temp, expr, len);
802 return prefixify_subexp (temp, expr, inpos, outpos);
805 /* Return the number of exp_elements in the postfix subexpression
806 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
809 length_of_subexp (struct expression *expr, int endpos)
813 operator_length (expr, endpos, &oplen, &args);
817 oplen += length_of_subexp (expr, endpos - oplen);
824 /* Sets *OPLENP to the length of the operator whose (last) index is
825 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
829 operator_length (const struct expression *expr, int endpos, int *oplenp,
832 expr->language_defn->la_exp_desc->operator_length (expr, endpos,
836 /* Default value for operator_length in exp_descriptor vectors. */
839 operator_length_standard (const struct expression *expr, int endpos,
840 int *oplenp, int *argsp)
844 enum range_type range_type;
848 error (_("?error in operator_length_standard"));
850 i = (int) expr->elts[endpos - 1].opcode;
856 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
857 oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
863 case OP_VAR_MSYM_VALUE:
867 case OP_FUNC_STATIC_VAR:
868 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
869 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
877 case OP_VAR_ENTRY_VALUE:
887 case OP_F77_UNDETERMINED_ARGLIST:
889 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
893 oplen = 5 + longest_to_int (expr->elts[endpos - 2].longconst);
897 case OP_OBJC_MSGCALL: /* Objective C message (method) call. */
899 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
908 case UNOP_DYNAMIC_CAST:
909 case UNOP_REINTERPRET_CAST:
910 case UNOP_MEMVAL_TYPE:
938 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
939 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
944 case STRUCTOP_STRUCT:
951 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
952 NSString constant. */
953 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
955 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
956 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
961 args = longest_to_int (expr->elts[endpos - 2].longconst);
962 args -= longest_to_int (expr->elts[endpos - 3].longconst);
972 case MULTI_SUBSCRIPT:
974 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
977 case BINOP_ASSIGN_MODIFY:
989 range_type = (enum range_type)
990 longest_to_int (expr->elts[endpos - 2].longconst);
994 case LOW_BOUND_DEFAULT:
995 case HIGH_BOUND_DEFAULT:
998 case BOTH_BOUND_DEFAULT:
1001 case NONE_BOUND_DEFAULT:
1009 args = 1 + (i < (int) BINOP_END);
1016 /* Copy the subexpression ending just before index INEND in INEXPR
1017 into OUTEXPR, starting at index OUTBEG.
1018 In the process, convert it from suffix to prefix form.
1019 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1020 Otherwise, it returns the index of the subexpression which is the
1021 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1024 prefixify_subexp (struct expression *inexpr,
1025 struct expression *outexpr, int inend, int outbeg)
1033 operator_length (inexpr, inend, &oplen, &args);
1035 /* Copy the final operator itself, from the end of the input
1036 to the beginning of the output. */
1038 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1039 EXP_ELEM_TO_BYTES (oplen));
1042 if (expout_last_struct == inend)
1043 result = outbeg - oplen;
1045 /* Find the lengths of the arg subexpressions. */
1046 arglens = (int *) alloca (args * sizeof (int));
1047 for (i = args - 1; i >= 0; i--)
1049 oplen = length_of_subexp (inexpr, inend);
1054 /* Now copy each subexpression, preserving the order of
1055 the subexpressions, but prefixifying each one.
1056 In this loop, inend starts at the beginning of
1057 the expression this level is working on
1058 and marches forward over the arguments.
1059 outbeg does similarly in the output. */
1060 for (i = 0; i < args; i++)
1066 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1069 /* Return immediately. We probably have only parsed a
1070 partial expression, so we don't want to try to reverse
1071 the other operands. */
1080 /* Read an expression from the string *STRINGPTR points to,
1081 parse it, and return a pointer to a struct expression that we malloc.
1082 Use block BLOCK as the lexical context for variable names;
1083 if BLOCK is zero, use the block of the selected stack frame.
1084 Meanwhile, advance *STRINGPTR to point after the expression,
1085 at the first nonwhite character that is not part of the expression
1086 (possibly a null character).
1088 If COMMA is nonzero, stop if a comma is reached. */
1091 parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
1094 return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL);
1097 static expression_up
1098 parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
1099 const struct block *block,
1100 int comma, int void_context_p, int *out_subexp)
1102 return parse_exp_in_context_1 (stringptr, pc, block, comma,
1103 void_context_p, out_subexp);
1106 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1107 no value is expected from the expression.
1108 OUT_SUBEXP is set when attempting to complete a field name; in this
1109 case it is set to the index of the subexpression on the
1110 left-hand-side of the struct op. If not doing such completion, it
1111 is left untouched. */
1113 static expression_up
1114 parse_exp_in_context_1 (const char **stringptr, CORE_ADDR pc,
1115 const struct block *block,
1116 int comma, int void_context_p, int *out_subexp)
1118 const struct language_defn *lang = NULL;
1119 struct parser_state ps;
1122 lexptr = *stringptr;
1126 type_stack.depth = 0;
1127 expout_last_struct = -1;
1128 expout_tag_completion_type = TYPE_CODE_UNDEF;
1129 xfree (expout_completion_name);
1130 expout_completion_name = NULL;
1132 comma_terminates = comma;
1134 if (lexptr == 0 || *lexptr == 0)
1135 error_no_arg (_("expression to compute"));
1137 std::vector<int> funcalls;
1138 scoped_restore save_funcall_chain = make_scoped_restore (&funcall_chain,
1141 expression_context_block = block;
1143 /* If no context specified, try using the current frame, if any. */
1144 if (!expression_context_block)
1145 expression_context_block = get_selected_block (&expression_context_pc);
1147 expression_context_pc = BLOCK_START (expression_context_block);
1149 expression_context_pc = pc;
1151 /* Fall back to using the current source static context, if any. */
1153 if (!expression_context_block)
1155 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1157 expression_context_block
1158 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
1160 if (expression_context_block)
1161 expression_context_pc = BLOCK_START (expression_context_block);
1164 if (language_mode == language_mode_auto && block != NULL)
1166 /* Find the language associated to the given context block.
1167 Default to the current language if it can not be determined.
1169 Note that using the language corresponding to the current frame
1170 can sometimes give unexpected results. For instance, this
1171 routine is often called several times during the inferior
1172 startup phase to re-parse breakpoint expressions after
1173 a new shared library has been loaded. The language associated
1174 to the current frame at this moment is not relevant for
1175 the breakpoint. Using it would therefore be silly, so it seems
1176 better to rely on the current language rather than relying on
1177 the current frame language to parse the expression. That's why
1178 we do the following language detection only if the context block
1179 has been specifically provided. */
1180 struct symbol *func = block_linkage_function (block);
1183 lang = language_def (SYMBOL_LANGUAGE (func));
1184 if (lang == NULL || lang->la_language == language_unknown)
1185 lang = current_language;
1188 lang = current_language;
1190 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1191 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1192 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1193 to the value matching SELECTED_FRAME as set by get_current_arch. */
1195 initialize_expout (&ps, 10, lang, get_current_arch ());
1197 scoped_restore_current_language lang_saver;
1198 set_language (lang->la_language);
1202 if (lang->la_parser (&ps))
1203 lang->la_error (NULL);
1205 CATCH (except, RETURN_MASK_ALL)
1207 if (! parse_completion)
1210 throw_exception (except);
1215 reallocate_expout (&ps);
1217 /* Convert expression from postfix form as generated by yacc
1218 parser, to a prefix form. */
1220 if (expressiondebug)
1221 dump_raw_expression (ps.expout, gdb_stdlog,
1222 "before conversion to prefix form");
1224 subexp = prefixify_expression (ps.expout);
1226 *out_subexp = subexp;
1228 lang->la_post_parser (&ps.expout, void_context_p);
1230 if (expressiondebug)
1231 dump_prefix_expression (ps.expout, gdb_stdlog);
1233 *stringptr = lexptr;
1234 return expression_up (ps.expout);
1237 /* Parse STRING as an expression, and complain if this fails
1238 to use up all of the contents of STRING. */
1241 parse_expression (const char *string)
1243 expression_up exp = parse_exp_1 (&string, 0, 0, 0);
1245 error (_("Junk after end of expression."));
1249 /* Same as parse_expression, but using the given language (LANG)
1250 to parse the expression. */
1253 parse_expression_with_language (const char *string, enum language lang)
1255 gdb::optional<scoped_restore_current_language> lang_saver;
1256 if (current_language->la_language != lang)
1258 lang_saver.emplace ();
1259 set_language (lang);
1262 return parse_expression (string);
1265 /* Parse STRING as an expression. If parsing ends in the middle of a
1266 field reference, return the type of the left-hand-side of the
1267 reference; furthermore, if the parsing ends in the field name,
1268 return the field name in *NAME. If the parsing ends in the middle
1269 of a field reference, but the reference is somehow invalid, throw
1270 an exception. In all other cases, return NULL. Returned non-NULL
1271 *NAME must be freed by the caller. */
1274 parse_expression_for_completion (const char *string, char **name,
1275 enum type_code *code)
1283 parse_completion = 1;
1284 exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp);
1286 CATCH (except, RETURN_MASK_ERROR)
1288 /* Nothing, EXP remains NULL. */
1292 parse_completion = 0;
1296 if (expout_tag_completion_type != TYPE_CODE_UNDEF)
1298 *code = expout_tag_completion_type;
1299 *name = expout_completion_name;
1300 expout_completion_name = NULL;
1304 if (expout_last_struct == -1)
1307 *name = extract_field_op (exp.get (), &subexp);
1311 /* This might throw an exception. If so, we want to let it
1313 val = evaluate_subexpression_type (exp.get (), subexp);
1314 /* (*NAME) is a part of the EXP memory block freed below. */
1315 *name = xstrdup (*name);
1317 return value_type (val);
1320 /* A post-parser that does nothing. */
1323 null_post_parser (struct expression **exp, int void_context_p)
1327 /* Parse floating point value P of length LEN.
1328 Return false if invalid, true if valid.
1329 The successfully parsed number is stored in DATA in
1330 target format for floating-point type TYPE.
1332 NOTE: This accepts the floating point syntax that sscanf accepts. */
1335 parse_float (const char *p, int len,
1336 const struct type *type, gdb_byte *data)
1338 return target_float_from_string (data, type, std::string (p, len));
1341 /* Stuff for maintaining a stack of types. Currently just used by C, but
1342 probably useful for any language which declares its types "backwards". */
1344 /* Ensure that there are HOWMUCH open slots on the type stack STACK. */
1347 type_stack_reserve (struct type_stack *stack, int howmuch)
1349 if (stack->depth + howmuch >= stack->size)
1352 if (stack->size < howmuch)
1353 stack->size = howmuch;
1354 stack->elements = XRESIZEVEC (union type_stack_elt, stack->elements,
1359 /* Ensure that there is a single open slot in the global type stack. */
1362 check_type_stack_depth (void)
1364 type_stack_reserve (&type_stack, 1);
1367 /* A helper function for insert_type and insert_type_address_space.
1368 This does work of expanding the type stack and inserting the new
1369 element, ELEMENT, into the stack at location SLOT. */
1372 insert_into_type_stack (int slot, union type_stack_elt element)
1374 check_type_stack_depth ();
1376 if (slot < type_stack.depth)
1377 memmove (&type_stack.elements[slot + 1], &type_stack.elements[slot],
1378 (type_stack.depth - slot) * sizeof (union type_stack_elt));
1379 type_stack.elements[slot] = element;
1383 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1384 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1385 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1386 previous tp_pointer) if there is anything on the stack, or simply pushed
1387 if the stack is empty. Other values for TP are invalid. */
1390 insert_type (enum type_pieces tp)
1392 union type_stack_elt element;
1395 gdb_assert (tp == tp_pointer || tp == tp_reference
1396 || tp == tp_rvalue_reference || tp == tp_const
1397 || tp == tp_volatile);
1399 /* If there is anything on the stack (we know it will be a
1400 tp_pointer), insert the qualifier above it. Otherwise, simply
1401 push this on the top of the stack. */
1402 if (type_stack.depth && (tp == tp_const || tp == tp_volatile))
1408 insert_into_type_stack (slot, element);
1412 push_type (enum type_pieces tp)
1414 check_type_stack_depth ();
1415 type_stack.elements[type_stack.depth++].piece = tp;
1419 push_type_int (int n)
1421 check_type_stack_depth ();
1422 type_stack.elements[type_stack.depth++].int_val = n;
1425 /* Insert a tp_space_identifier and the corresponding address space
1426 value into the stack. STRING is the name of an address space, as
1427 recognized by address_space_name_to_int. If the stack is empty,
1428 the new elements are simply pushed. If the stack is not empty,
1429 this function assumes that the first item on the stack is a
1430 tp_pointer, and the new values are inserted above the first
1434 insert_type_address_space (struct parser_state *pstate, char *string)
1436 union type_stack_elt element;
1439 /* If there is anything on the stack (we know it will be a
1440 tp_pointer), insert the address space qualifier above it.
1441 Otherwise, simply push this on the top of the stack. */
1442 if (type_stack.depth)
1447 element.piece = tp_space_identifier;
1448 insert_into_type_stack (slot, element);
1449 element.int_val = address_space_name_to_int (parse_gdbarch (pstate),
1451 insert_into_type_stack (slot, element);
1457 if (type_stack.depth)
1458 return type_stack.elements[--type_stack.depth].piece;
1465 if (type_stack.depth)
1466 return type_stack.elements[--type_stack.depth].int_val;
1467 /* "Can't happen". */
1471 /* Pop a type list element from the global type stack. */
1473 static VEC (type_ptr) *
1476 gdb_assert (type_stack.depth);
1477 return type_stack.elements[--type_stack.depth].typelist_val;
1480 /* Pop a type_stack element from the global type stack. */
1482 static struct type_stack *
1483 pop_type_stack (void)
1485 gdb_assert (type_stack.depth);
1486 return type_stack.elements[--type_stack.depth].stack_val;
1489 /* Append the elements of the type stack FROM to the type stack TO.
1490 Always returns TO. */
1493 append_type_stack (struct type_stack *to, struct type_stack *from)
1495 type_stack_reserve (to, from->depth);
1497 memcpy (&to->elements[to->depth], &from->elements[0],
1498 from->depth * sizeof (union type_stack_elt));
1499 to->depth += from->depth;
1504 /* Push the type stack STACK as an element on the global type stack. */
1507 push_type_stack (struct type_stack *stack)
1509 check_type_stack_depth ();
1510 type_stack.elements[type_stack.depth++].stack_val = stack;
1511 push_type (tp_type_stack);
1514 /* Copy the global type stack into a newly allocated type stack and
1515 return it. The global stack is cleared. The returned type stack
1516 must be freed with type_stack_cleanup. */
1519 get_type_stack (void)
1521 struct type_stack *result = XNEW (struct type_stack);
1523 *result = type_stack;
1524 type_stack.depth = 0;
1525 type_stack.size = 0;
1526 type_stack.elements = NULL;
1531 /* A cleanup function that destroys a single type stack. */
1534 type_stack_cleanup (void *arg)
1536 struct type_stack *stack = (struct type_stack *) arg;
1538 xfree (stack->elements);
1542 /* Push a function type with arguments onto the global type stack.
1543 LIST holds the argument types. If the final item in LIST is NULL,
1544 then the function will be varargs. */
1547 push_typelist (VEC (type_ptr) *list)
1549 check_type_stack_depth ();
1550 type_stack.elements[type_stack.depth++].typelist_val = list;
1551 push_type (tp_function_with_arguments);
1554 /* Pop the type stack and return a type_instance_flags that
1555 corresponds the const/volatile qualifiers on the stack. This is
1556 called by the C++ parser when parsing methods types, and as such no
1557 other kind of type in the type stack is expected. */
1560 follow_type_instance_flags ()
1562 type_instance_flags flags = 0;
1565 switch (pop_type ())
1570 flags |= TYPE_INSTANCE_FLAG_CONST;
1573 flags |= TYPE_INSTANCE_FLAG_VOLATILE;
1576 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1581 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1582 as modified by all the stuff on the stack. */
1584 follow_types (struct type *follow_type)
1588 int make_volatile = 0;
1589 int make_addr_space = 0;
1593 switch (pop_type ())
1598 follow_type = make_cv_type (make_const,
1599 TYPE_VOLATILE (follow_type),
1602 follow_type = make_cv_type (TYPE_CONST (follow_type),
1605 if (make_addr_space)
1606 follow_type = make_type_with_address_space (follow_type,
1608 make_const = make_volatile = 0;
1609 make_addr_space = 0;
1617 case tp_space_identifier:
1618 make_addr_space = pop_type_int ();
1621 follow_type = lookup_pointer_type (follow_type);
1623 follow_type = make_cv_type (make_const,
1624 TYPE_VOLATILE (follow_type),
1627 follow_type = make_cv_type (TYPE_CONST (follow_type),
1630 if (make_addr_space)
1631 follow_type = make_type_with_address_space (follow_type,
1633 make_const = make_volatile = 0;
1634 make_addr_space = 0;
1637 follow_type = lookup_lvalue_reference_type (follow_type);
1638 goto process_reference;
1639 case tp_rvalue_reference:
1640 follow_type = lookup_rvalue_reference_type (follow_type);
1643 follow_type = make_cv_type (make_const,
1644 TYPE_VOLATILE (follow_type),
1647 follow_type = make_cv_type (TYPE_CONST (follow_type),
1650 if (make_addr_space)
1651 follow_type = make_type_with_address_space (follow_type,
1653 make_const = make_volatile = 0;
1654 make_addr_space = 0;
1657 array_size = pop_type_int ();
1658 /* FIXME-type-allocation: need a way to free this type when we are
1661 lookup_array_range_type (follow_type,
1662 0, array_size >= 0 ? array_size - 1 : 0);
1664 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type))
1668 /* FIXME-type-allocation: need a way to free this type when we are
1670 follow_type = lookup_function_type (follow_type);
1673 case tp_function_with_arguments:
1675 VEC (type_ptr) *args = pop_typelist ();
1678 = lookup_function_type_with_arguments (follow_type,
1679 VEC_length (type_ptr, args),
1680 VEC_address (type_ptr,
1682 VEC_free (type_ptr, args);
1688 struct type_stack *stack = pop_type_stack ();
1689 /* Sort of ugly, but not really much worse than the
1691 struct type_stack save = type_stack;
1693 type_stack = *stack;
1694 follow_type = follow_types (follow_type);
1695 gdb_assert (type_stack.depth == 0);
1701 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1706 /* This function avoids direct calls to fprintf
1707 in the parser generated debug code. */
1709 parser_fprintf (FILE *x, const char *y, ...)
1715 vfprintf_unfiltered (gdb_stderr, y, args);
1718 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1719 vfprintf_unfiltered (gdb_stderr, y, args);
1724 /* Implementation of the exp_descriptor method operator_check. */
1727 operator_check_standard (struct expression *exp, int pos,
1728 int (*objfile_func) (struct objfile *objfile,
1732 const union exp_element *const elts = exp->elts;
1733 struct type *type = NULL;
1734 struct objfile *objfile = NULL;
1736 /* Extended operators should have been already handled by exp_descriptor
1737 iterate method of its specific language. */
1738 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1740 /* Track the callers of write_exp_elt_type for this table. */
1742 switch (elts[pos].opcode)
1754 type = elts[pos + 1].type;
1759 LONGEST arg, nargs = elts[pos + 2].longconst;
1761 for (arg = 0; arg < nargs; arg++)
1763 struct type *type = elts[pos + 3 + arg].type;
1764 struct objfile *objfile = TYPE_OBJFILE (type);
1766 if (objfile && (*objfile_func) (objfile, data))
1774 const struct block *const block = elts[pos + 1].block;
1775 const struct symbol *const symbol = elts[pos + 2].symbol;
1777 /* Check objfile where the variable itself is placed.
1778 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1779 if ((*objfile_func) (symbol_objfile (symbol), data))
1782 /* Check objfile where is placed the code touching the variable. */
1783 objfile = lookup_objfile_from_block (block);
1785 type = SYMBOL_TYPE (symbol);
1788 case OP_VAR_MSYM_VALUE:
1789 objfile = elts[pos + 1].objfile;
1793 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1795 if (type && TYPE_OBJFILE (type)
1796 && (*objfile_func) (TYPE_OBJFILE (type), data))
1798 if (objfile && (*objfile_func) (objfile, data))
1804 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1805 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1806 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1807 returns non-zero value then (any other) non-zero value is immediately
1808 returned to the caller. Otherwise zero is returned after iterating
1809 through whole EXP. */
1812 exp_iterate (struct expression *exp,
1813 int (*objfile_func) (struct objfile *objfile, void *data),
1818 for (endpos = exp->nelts; endpos > 0; )
1820 int pos, args, oplen = 0;
1822 operator_length (exp, endpos, &oplen, &args);
1823 gdb_assert (oplen > 0);
1825 pos = endpos - oplen;
1826 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1827 objfile_func, data))
1836 /* Helper for exp_uses_objfile. */
1839 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1841 struct objfile *objfile = (struct objfile *) objfile_voidp;
1843 if (exp_objfile->separate_debug_objfile_backlink)
1844 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1846 return exp_objfile == objfile;
1849 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1850 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1854 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1856 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1858 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1861 /* See definition in parser-defs.h. */
1864 increase_expout_size (struct parser_state *ps, size_t lenelt)
1866 if ((ps->expout_ptr + lenelt) >= ps->expout_size)
1868 ps->expout_size = std::max (ps->expout_size * 2,
1869 ps->expout_ptr + lenelt + 10);
1870 ps->expout = (struct expression *)
1871 xrealloc (ps->expout, (sizeof (struct expression)
1872 + EXP_ELEM_TO_BYTES (ps->expout_size)));
1877 _initialize_parse (void)
1879 type_stack.size = 0;
1880 type_stack.depth = 0;
1881 type_stack.elements = NULL;
1883 add_setshow_zuinteger_cmd ("expression", class_maintenance,
1885 _("Set expression debugging."),
1886 _("Show expression debugging."),
1887 _("When non-zero, the internal representation "
1888 "of expressions will be printed."),
1890 show_expressiondebug,
1891 &setdebuglist, &showdebuglist);
1892 add_setshow_boolean_cmd ("parser", class_maintenance,
1894 _("Set parser debugging."),
1895 _("Show parser debugging."),
1896 _("When non-zero, expression parser "
1897 "tracing will be enabled."),
1900 &setdebuglist, &showdebuglist);