1 /* Parse expressions for GDB.
3 Copyright (C) 1986-2019 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 innermost_block_tracker 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 gdb::unique_xmalloc_ptr<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 innermost_block_tracker_types);
122 /* Documented at it's declaration. */
125 innermost_block_tracker::update (const struct block *b,
126 innermost_block_tracker_types t)
128 if ((m_types & t) != 0
129 && (m_innermost_block == NULL
130 || contained_in (b, m_innermost_block)))
131 m_innermost_block = b;
134 /* Data structure for saving values of arglist_len for function calls whose
135 arguments contain other function calls. */
137 static std::vector<int> *funcall_chain;
139 /* Begin counting arguments for a function call,
140 saving the data about any containing call. */
145 funcall_chain->push_back (arglist_len);
149 /* Return the number of arguments in a function call just terminated,
150 and restore the data for the containing function call. */
155 int val = arglist_len;
156 arglist_len = funcall_chain->back ();
157 funcall_chain->pop_back ();
163 /* See definition in parser-defs.h. */
165 parser_state::parser_state (size_t initial_size,
166 const struct language_defn *lang,
167 struct gdbarch *gdbarch)
168 : expout_size (initial_size),
169 expout (XNEWVAR (expression,
171 + EXP_ELEM_TO_BYTES (expout_size)))),
174 expout->language_defn = lang;
175 expout->gdbarch = gdbarch;
179 parser_state::release ()
181 /* Record the actual number of expression elements, and then
182 reallocate the expression memory so that we free up any
185 expout->nelts = expout_ptr;
186 expout.reset (XRESIZEVAR (expression, expout.release (),
188 + EXP_ELEM_TO_BYTES (expout_ptr))));
190 return std::move (expout);
193 /* This page contains the functions for adding data to the struct expression
194 being constructed. */
196 /* Add one element to the end of the expression. */
198 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
199 a register through here. */
202 write_exp_elt (struct parser_state *ps, const union exp_element *expelt)
204 if (ps->expout_ptr >= ps->expout_size)
206 ps->expout_size *= 2;
207 ps->expout.reset (XRESIZEVAR (expression, ps->expout.release (),
209 + EXP_ELEM_TO_BYTES (ps->expout_size))));
211 ps->expout->elts[ps->expout_ptr++] = *expelt;
215 write_exp_elt_opcode (struct parser_state *ps, enum exp_opcode expelt)
217 union exp_element tmp;
219 memset (&tmp, 0, sizeof (union exp_element));
221 write_exp_elt (ps, &tmp);
225 write_exp_elt_sym (struct parser_state *ps, struct symbol *expelt)
227 union exp_element tmp;
229 memset (&tmp, 0, sizeof (union exp_element));
231 write_exp_elt (ps, &tmp);
235 write_exp_elt_msym (struct parser_state *ps, minimal_symbol *expelt)
237 union exp_element tmp;
239 memset (&tmp, 0, sizeof (union exp_element));
240 tmp.msymbol = expelt;
241 write_exp_elt (ps, &tmp);
245 write_exp_elt_block (struct parser_state *ps, const struct block *b)
247 union exp_element tmp;
249 memset (&tmp, 0, sizeof (union exp_element));
251 write_exp_elt (ps, &tmp);
255 write_exp_elt_objfile (struct parser_state *ps, struct objfile *objfile)
257 union exp_element tmp;
259 memset (&tmp, 0, sizeof (union exp_element));
260 tmp.objfile = objfile;
261 write_exp_elt (ps, &tmp);
265 write_exp_elt_longcst (struct parser_state *ps, LONGEST expelt)
267 union exp_element tmp;
269 memset (&tmp, 0, sizeof (union exp_element));
270 tmp.longconst = expelt;
271 write_exp_elt (ps, &tmp);
275 write_exp_elt_floatcst (struct parser_state *ps, const gdb_byte expelt[16])
277 union exp_element tmp;
280 for (index = 0; index < 16; index++)
281 tmp.floatconst[index] = expelt[index];
283 write_exp_elt (ps, &tmp);
287 write_exp_elt_type (struct parser_state *ps, struct type *expelt)
289 union exp_element tmp;
291 memset (&tmp, 0, sizeof (union exp_element));
293 write_exp_elt (ps, &tmp);
297 write_exp_elt_intern (struct parser_state *ps, struct internalvar *expelt)
299 union exp_element tmp;
301 memset (&tmp, 0, sizeof (union exp_element));
302 tmp.internalvar = expelt;
303 write_exp_elt (ps, &tmp);
306 /* Add a string constant to the end of the expression.
308 String constants are stored by first writing an expression element
309 that contains the length of the string, then stuffing the string
310 constant itself into however many expression elements are needed
311 to hold it, and then writing another expression element that contains
312 the length of the string. I.e. an expression element at each end of
313 the string records the string length, so you can skip over the
314 expression elements containing the actual string bytes from either
315 end of the string. Note that this also allows gdb to handle
316 strings with embedded null bytes, as is required for some languages.
318 Don't be fooled by the fact that the string is null byte terminated,
319 this is strictly for the convenience of debugging gdb itself.
320 Gdb does not depend up the string being null terminated, since the
321 actual length is recorded in expression elements at each end of the
322 string. The null byte is taken into consideration when computing how
323 many expression elements are required to hold the string constant, of
328 write_exp_string (struct parser_state *ps, struct stoken str)
330 int len = str.length;
334 /* Compute the number of expression elements required to hold the string
335 (including a null byte terminator), along with one expression element
336 at each end to record the actual string length (not including the
337 null byte terminator). */
339 lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);
341 increase_expout_size (ps, lenelt);
343 /* Write the leading length expression element (which advances the current
344 expression element index), then write the string constant followed by a
345 terminating null byte, and then write the trailing length expression
348 write_exp_elt_longcst (ps, (LONGEST) len);
349 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
350 memcpy (strdata, str.ptr, len);
351 *(strdata + len) = '\0';
352 ps->expout_ptr += lenelt - 2;
353 write_exp_elt_longcst (ps, (LONGEST) len);
356 /* Add a vector of string constants to the end of the expression.
358 This adds an OP_STRING operation, but encodes the contents
359 differently from write_exp_string. The language is expected to
360 handle evaluation of this expression itself.
362 After the usual OP_STRING header, TYPE is written into the
363 expression as a long constant. The interpretation of this field is
364 up to the language evaluator.
366 Next, each string in VEC is written. The length is written as a
367 long constant, followed by the contents of the string. */
370 write_exp_string_vector (struct parser_state *ps, int type,
371 struct stoken_vector *vec)
376 /* Compute the size. We compute the size in number of slots to
377 avoid issues with string padding. */
379 for (i = 0; i < vec->len; ++i)
381 /* One slot for the length of this element, plus the number of
382 slots needed for this string. */
383 n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
386 /* One more slot for the type of the string. */
389 /* Now compute a phony string length. */
390 len = EXP_ELEM_TO_BYTES (n_slots) - 1;
393 increase_expout_size (ps, n_slots);
395 write_exp_elt_opcode (ps, OP_STRING);
396 write_exp_elt_longcst (ps, len);
397 write_exp_elt_longcst (ps, type);
399 for (i = 0; i < vec->len; ++i)
401 write_exp_elt_longcst (ps, vec->tokens[i].length);
402 memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr,
403 vec->tokens[i].length);
404 ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
407 write_exp_elt_longcst (ps, len);
408 write_exp_elt_opcode (ps, OP_STRING);
411 /* Add a bitstring constant to the end of the expression.
413 Bitstring constants are stored by first writing an expression element
414 that contains the length of the bitstring (in bits), then stuffing the
415 bitstring constant itself into however many expression elements are
416 needed to hold it, and then writing another expression element that
417 contains the length of the bitstring. I.e. an expression element at
418 each end of the bitstring records the bitstring length, so you can skip
419 over the expression elements containing the actual bitstring bytes from
420 either end of the bitstring. */
423 write_exp_bitstring (struct parser_state *ps, struct stoken str)
425 int bits = str.length; /* length in bits */
426 int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
430 /* Compute the number of expression elements required to hold the bitstring,
431 along with one expression element at each end to record the actual
432 bitstring length in bits. */
434 lenelt = 2 + BYTES_TO_EXP_ELEM (len);
436 increase_expout_size (ps, lenelt);
438 /* Write the leading length expression element (which advances the current
439 expression element index), then write the bitstring constant, and then
440 write the trailing length expression element. */
442 write_exp_elt_longcst (ps, (LONGEST) bits);
443 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
444 memcpy (strdata, str.ptr, len);
445 ps->expout_ptr += lenelt - 2;
446 write_exp_elt_longcst (ps, (LONGEST) bits);
449 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
450 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
454 find_minsym_type_and_address (minimal_symbol *msymbol,
455 struct objfile *objfile,
456 CORE_ADDR *address_p)
458 bound_minimal_symbol bound_msym = {msymbol, objfile};
459 struct obj_section *section = MSYMBOL_OBJ_SECTION (objfile, msymbol);
460 enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
462 bool is_tls = (section != NULL
463 && section->the_bfd_section->flags & SEC_THREAD_LOCAL);
465 /* The minimal symbol might point to a function descriptor;
466 resolve it to the actual code address instead. */
470 /* Addresses of TLS symbols are really offsets into a
471 per-objfile/per-thread storage block. */
472 addr = MSYMBOL_VALUE_RAW_ADDRESS (bound_msym.minsym);
474 else if (msymbol_is_function (objfile, msymbol, &addr))
476 if (addr != BMSYMBOL_VALUE_ADDRESS (bound_msym))
478 /* This means we resolved a function descriptor, and we now
479 have an address for a code/text symbol instead of a data
481 if (MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc)
482 type = mst_text_gnu_ifunc;
489 addr = BMSYMBOL_VALUE_ADDRESS (bound_msym);
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.reset (xstrndup (ptr, length));
572 /* Recognize tokens that start with '$'. These include:
574 $regname A native register name or a "standard
577 $variable A convenience variable with a name chosen
580 $digits Value history with index <digits>, starting
581 from the first value which has index 1.
583 $$digits Value history with index <digits> relative
584 to the last value. I.e. $$0 is the last
585 value, $$1 is the one previous to that, $$2
586 is the one previous to $$1, etc.
588 $ | $0 | $$0 The last value in the value history.
590 $$ An abbreviation for the second to the last
591 value in the value history, I.e. $$1 */
594 write_dollar_variable (struct parser_state *ps, struct stoken str)
596 struct block_symbol sym;
597 struct bound_minimal_symbol msym;
598 struct internalvar *isym = NULL;
600 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
601 and $$digits (equivalent to $<-digits> if you could type that). */
605 /* Double dollar means negate the number and add -1 as well.
606 Thus $$ alone means -1. */
607 if (str.length >= 2 && str.ptr[1] == '$')
614 /* Just dollars (one or two). */
618 /* Is the rest of the token digits? */
619 for (; i < str.length; i++)
620 if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
624 i = atoi (str.ptr + 1 + negate);
630 /* Handle tokens that refer to machine registers:
631 $ followed by a register name. */
632 i = user_reg_map_name_to_regnum (parse_gdbarch (ps),
633 str.ptr + 1, str.length - 1);
635 goto handle_register;
637 /* Any names starting with $ are probably debugger internal variables. */
639 isym = lookup_only_internalvar (copy_name (str) + 1);
642 write_exp_elt_opcode (ps, OP_INTERNALVAR);
643 write_exp_elt_intern (ps, isym);
644 write_exp_elt_opcode (ps, OP_INTERNALVAR);
648 /* On some systems, such as HP-UX and hppa-linux, certain system routines
649 have names beginning with $ or $$. Check for those, first. */
651 sym = lookup_symbol (copy_name (str), NULL, VAR_DOMAIN, NULL);
654 write_exp_elt_opcode (ps, OP_VAR_VALUE);
655 write_exp_elt_block (ps, sym.block);
656 write_exp_elt_sym (ps, sym.symbol);
657 write_exp_elt_opcode (ps, OP_VAR_VALUE);
660 msym = lookup_bound_minimal_symbol (copy_name (str));
663 write_exp_msymbol (ps, msym);
667 /* Any other names are assumed to be debugger internal variables. */
669 write_exp_elt_opcode (ps, OP_INTERNALVAR);
670 write_exp_elt_intern (ps, create_internalvar (copy_name (str) + 1));
671 write_exp_elt_opcode (ps, OP_INTERNALVAR);
674 write_exp_elt_opcode (ps, OP_LAST);
675 write_exp_elt_longcst (ps, (LONGEST) i);
676 write_exp_elt_opcode (ps, OP_LAST);
679 write_exp_elt_opcode (ps, OP_REGISTER);
682 write_exp_string (ps, str);
683 write_exp_elt_opcode (ps, OP_REGISTER);
684 innermost_block.update (expression_context_block,
685 INNERMOST_BLOCK_FOR_REGISTERS);
691 find_template_name_end (const char *p)
694 int just_seen_right = 0;
695 int just_seen_colon = 0;
696 int just_seen_space = 0;
698 if (!p || (*p != '<'))
709 /* In future, may want to allow these?? */
712 depth++; /* start nested template */
713 if (just_seen_colon || just_seen_right || just_seen_space)
714 return 0; /* but not after : or :: or > or space */
717 if (just_seen_colon || just_seen_right)
718 return 0; /* end a (nested?) template */
719 just_seen_right = 1; /* but not after : or :: */
720 if (--depth == 0) /* also disallow >>, insist on > > */
721 return ++p; /* if outermost ended, return */
724 if (just_seen_space || (just_seen_colon > 1))
725 return 0; /* nested class spec coming up */
726 just_seen_colon++; /* we allow :: but not :::: */
731 if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
732 (*p >= 'A' && *p <= 'Z') ||
733 (*p >= '0' && *p <= '9') ||
734 (*p == '_') || (*p == ',') || /* commas for template args */
735 (*p == '&') || (*p == '*') || /* pointer and ref types */
736 (*p == '(') || (*p == ')') || /* function types */
737 (*p == '[') || (*p == ']'))) /* array types */
751 /* Return a null-terminated temporary copy of the name of a string token.
753 Tokens that refer to names do so with explicit pointer and length,
754 so they can share the storage that lexptr is parsing.
755 When it is necessary to pass a name to a function that expects
756 a null-terminated string, the substring is copied out
757 into a separate block of storage.
759 N.B. A single buffer is reused on each call. */
762 copy_name (struct stoken token)
764 /* A temporary buffer for identifiers, so we can null-terminate them.
765 We allocate this with xrealloc. parse_exp_1 used to allocate with
766 alloca, using the size of the whole expression as a conservative
767 estimate of the space needed. However, macro expansion can
768 introduce names longer than the original expression; there's no
769 practical way to know beforehand how large that might be. */
770 static char *namecopy;
771 static size_t namecopy_size;
773 /* Make sure there's enough space for the token. */
774 if (namecopy_size < token.length + 1)
776 namecopy_size = token.length + 1;
777 namecopy = (char *) xrealloc (namecopy, token.length + 1);
780 memcpy (namecopy, token.ptr, token.length);
781 namecopy[token.length] = 0;
787 /* See comments on parser-defs.h. */
790 prefixify_expression (struct expression *expr)
792 gdb_assert (expr->nelts > 0);
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:
939 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
940 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
945 case STRUCTOP_STRUCT:
952 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
953 NSString constant. */
954 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
956 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
957 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
962 args = longest_to_int (expr->elts[endpos - 2].longconst);
963 args -= longest_to_int (expr->elts[endpos - 3].longconst);
973 case MULTI_SUBSCRIPT:
975 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
978 case BINOP_ASSIGN_MODIFY:
990 range_type = (enum range_type)
991 longest_to_int (expr->elts[endpos - 2].longconst);
995 case LOW_BOUND_DEFAULT:
996 case LOW_BOUND_DEFAULT_EXCLUSIVE:
997 case HIGH_BOUND_DEFAULT:
1000 case BOTH_BOUND_DEFAULT:
1003 case NONE_BOUND_DEFAULT:
1004 case NONE_BOUND_DEFAULT_EXCLUSIVE:
1012 args = 1 + (i < (int) BINOP_END);
1019 /* Copy the subexpression ending just before index INEND in INEXPR
1020 into OUTEXPR, starting at index OUTBEG.
1021 In the process, convert it from suffix to prefix form.
1022 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1023 Otherwise, it returns the index of the subexpression which is the
1024 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1027 prefixify_subexp (struct expression *inexpr,
1028 struct expression *outexpr, int inend, int outbeg)
1036 operator_length (inexpr, inend, &oplen, &args);
1038 /* Copy the final operator itself, from the end of the input
1039 to the beginning of the output. */
1041 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1042 EXP_ELEM_TO_BYTES (oplen));
1045 if (expout_last_struct == inend)
1046 result = outbeg - oplen;
1048 /* Find the lengths of the arg subexpressions. */
1049 arglens = (int *) alloca (args * sizeof (int));
1050 for (i = args - 1; i >= 0; i--)
1052 oplen = length_of_subexp (inexpr, inend);
1057 /* Now copy each subexpression, preserving the order of
1058 the subexpressions, but prefixifying each one.
1059 In this loop, inend starts at the beginning of
1060 the expression this level is working on
1061 and marches forward over the arguments.
1062 outbeg does similarly in the output. */
1063 for (i = 0; i < args; i++)
1069 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1072 /* Return immediately. We probably have only parsed a
1073 partial expression, so we don't want to try to reverse
1074 the other operands. */
1083 /* Read an expression from the string *STRINGPTR points to,
1084 parse it, and return a pointer to a struct expression that we malloc.
1085 Use block BLOCK as the lexical context for variable names;
1086 if BLOCK is zero, use the block of the selected stack frame.
1087 Meanwhile, advance *STRINGPTR to point after the expression,
1088 at the first nonwhite character that is not part of the expression
1089 (possibly a null character).
1091 If COMMA is nonzero, stop if a comma is reached. */
1094 parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
1095 int comma, innermost_block_tracker_types tracker_types)
1097 return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL,
1101 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1102 no value is expected from the expression.
1103 OUT_SUBEXP is set when attempting to complete a field name; in this
1104 case it is set to the index of the subexpression on the
1105 left-hand-side of the struct op. If not doing such completion, it
1106 is left untouched. */
1108 static expression_up
1109 parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
1110 const struct block *block,
1111 int comma, int void_context_p, int *out_subexp,
1112 innermost_block_tracker_types tracker_types)
1114 const struct language_defn *lang = NULL;
1117 lexptr = *stringptr;
1121 type_stack.elements.clear ();
1122 expout_last_struct = -1;
1123 expout_tag_completion_type = TYPE_CODE_UNDEF;
1124 expout_completion_name.reset ();
1125 innermost_block.reset (tracker_types);
1127 comma_terminates = comma;
1129 if (lexptr == 0 || *lexptr == 0)
1130 error_no_arg (_("expression to compute"));
1132 std::vector<int> funcalls;
1133 scoped_restore save_funcall_chain = make_scoped_restore (&funcall_chain,
1136 expression_context_block = block;
1138 /* If no context specified, try using the current frame, if any. */
1139 if (!expression_context_block)
1140 expression_context_block = get_selected_block (&expression_context_pc);
1142 expression_context_pc = BLOCK_ENTRY_PC (expression_context_block);
1144 expression_context_pc = pc;
1146 /* Fall back to using the current source static context, if any. */
1148 if (!expression_context_block)
1150 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1152 expression_context_block
1153 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
1155 if (expression_context_block)
1156 expression_context_pc = BLOCK_ENTRY_PC (expression_context_block);
1159 if (language_mode == language_mode_auto && block != NULL)
1161 /* Find the language associated to the given context block.
1162 Default to the current language if it can not be determined.
1164 Note that using the language corresponding to the current frame
1165 can sometimes give unexpected results. For instance, this
1166 routine is often called several times during the inferior
1167 startup phase to re-parse breakpoint expressions after
1168 a new shared library has been loaded. The language associated
1169 to the current frame at this moment is not relevant for
1170 the breakpoint. Using it would therefore be silly, so it seems
1171 better to rely on the current language rather than relying on
1172 the current frame language to parse the expression. That's why
1173 we do the following language detection only if the context block
1174 has been specifically provided. */
1175 struct symbol *func = block_linkage_function (block);
1178 lang = language_def (SYMBOL_LANGUAGE (func));
1179 if (lang == NULL || lang->la_language == language_unknown)
1180 lang = current_language;
1183 lang = current_language;
1185 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1186 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1187 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1188 to the value matching SELECTED_FRAME as set by get_current_arch. */
1190 parser_state ps (10, lang, get_current_arch ());
1192 scoped_restore_current_language lang_saver;
1193 set_language (lang->la_language);
1197 lang->la_parser (&ps);
1199 CATCH (except, RETURN_MASK_ALL)
1201 /* If parsing for completion, allow this to succeed; but if no
1202 expression elements have been written, then there's nothing
1204 if (! parse_completion || ps.expout_ptr == 0)
1205 throw_exception (except);
1209 /* We have to operate on an "expression *", due to la_post_parser,
1210 which explains this funny-looking double release. */
1211 expression_up result = ps.release ();
1213 /* Convert expression from postfix form as generated by yacc
1214 parser, to a prefix form. */
1216 if (expressiondebug)
1217 dump_raw_expression (result.get (), gdb_stdlog,
1218 "before conversion to prefix form");
1220 subexp = prefixify_expression (result.get ());
1222 *out_subexp = subexp;
1224 lang->la_post_parser (&result, void_context_p);
1226 if (expressiondebug)
1227 dump_prefix_expression (result.get (), gdb_stdlog);
1229 *stringptr = lexptr;
1233 /* Parse STRING as an expression, and complain if this fails
1234 to use up all of the contents of STRING. */
1237 parse_expression (const char *string)
1239 expression_up exp = parse_exp_1 (&string, 0, 0, 0);
1241 error (_("Junk after end of expression."));
1245 /* Same as parse_expression, but using the given language (LANG)
1246 to parse the expression. */
1249 parse_expression_with_language (const char *string, enum language lang)
1251 gdb::optional<scoped_restore_current_language> lang_saver;
1252 if (current_language->la_language != lang)
1254 lang_saver.emplace ();
1255 set_language (lang);
1258 return parse_expression (string);
1261 /* Parse STRING as an expression. If parsing ends in the middle of a
1262 field reference, return the type of the left-hand-side of the
1263 reference; furthermore, if the parsing ends in the field name,
1264 return the field name in *NAME. If the parsing ends in the middle
1265 of a field reference, but the reference is somehow invalid, throw
1266 an exception. In all other cases, return NULL. */
1269 parse_expression_for_completion (const char *string,
1270 gdb::unique_xmalloc_ptr<char> *name,
1271 enum type_code *code)
1279 parse_completion = 1;
1280 exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp,
1281 INNERMOST_BLOCK_FOR_SYMBOLS);
1283 CATCH (except, RETURN_MASK_ERROR)
1285 /* Nothing, EXP remains NULL. */
1289 parse_completion = 0;
1293 if (expout_tag_completion_type != TYPE_CODE_UNDEF)
1295 *code = expout_tag_completion_type;
1296 *name = std::move (expout_completion_name);
1300 if (expout_last_struct == -1)
1303 const char *fieldname = extract_field_op (exp.get (), &subexp);
1304 if (fieldname == NULL)
1310 name->reset (xstrdup (fieldname));
1311 /* This might throw an exception. If so, we want to let it
1313 val = evaluate_subexpression_type (exp.get (), subexp);
1315 return value_type (val);
1318 /* A post-parser that does nothing. */
1321 null_post_parser (expression_up *exp, int void_context_p)
1325 /* Parse floating point value P of length LEN.
1326 Return false if invalid, true if valid.
1327 The successfully parsed number is stored in DATA in
1328 target format for floating-point type TYPE.
1330 NOTE: This accepts the floating point syntax that sscanf accepts. */
1333 parse_float (const char *p, int len,
1334 const struct type *type, gdb_byte *data)
1336 return target_float_from_string (data, type, std::string (p, len));
1339 /* Stuff for maintaining a stack of types. Currently just used by C, but
1340 probably useful for any language which declares its types "backwards". */
1342 /* A helper function for insert_type and insert_type_address_space.
1343 This does work of expanding the type stack and inserting the new
1344 element, ELEMENT, into the stack at location SLOT. */
1347 insert_into_type_stack (int slot, union type_stack_elt element)
1349 gdb_assert (slot <= type_stack.elements.size ());
1350 type_stack.elements.insert (type_stack.elements.begin () + slot, element);
1353 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1354 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1355 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1356 previous tp_pointer) if there is anything on the stack, or simply pushed
1357 if the stack is empty. Other values for TP are invalid. */
1360 insert_type (enum type_pieces tp)
1362 union type_stack_elt element;
1365 gdb_assert (tp == tp_pointer || tp == tp_reference
1366 || tp == tp_rvalue_reference || tp == tp_const
1367 || tp == tp_volatile);
1369 /* If there is anything on the stack (we know it will be a
1370 tp_pointer), insert the qualifier above it. Otherwise, simply
1371 push this on the top of the stack. */
1372 if (!type_stack.elements.empty () && (tp == tp_const || tp == tp_volatile))
1378 insert_into_type_stack (slot, element);
1382 push_type (enum type_pieces tp)
1386 type_stack.elements.push_back (elt);
1390 push_type_int (int n)
1394 type_stack.elements.push_back (elt);
1397 /* Insert a tp_space_identifier and the corresponding address space
1398 value into the stack. STRING is the name of an address space, as
1399 recognized by address_space_name_to_int. If the stack is empty,
1400 the new elements are simply pushed. If the stack is not empty,
1401 this function assumes that the first item on the stack is a
1402 tp_pointer, and the new values are inserted above the first
1406 insert_type_address_space (struct parser_state *pstate, char *string)
1408 union type_stack_elt element;
1411 /* If there is anything on the stack (we know it will be a
1412 tp_pointer), insert the address space qualifier above it.
1413 Otherwise, simply push this on the top of the stack. */
1414 if (!type_stack.elements.empty ())
1419 element.piece = tp_space_identifier;
1420 insert_into_type_stack (slot, element);
1421 element.int_val = address_space_name_to_int (parse_gdbarch (pstate),
1423 insert_into_type_stack (slot, element);
1429 if (!type_stack.elements.empty ())
1431 type_stack_elt elt = type_stack.elements.back ();
1432 type_stack.elements.pop_back ();
1441 if (!type_stack.elements.empty ())
1443 type_stack_elt elt = type_stack.elements.back ();
1444 type_stack.elements.pop_back ();
1447 /* "Can't happen". */
1451 /* Pop a type list element from the global type stack. */
1453 static std::vector<struct type *> *
1456 gdb_assert (!type_stack.elements.empty ());
1457 type_stack_elt elt = type_stack.elements.back ();
1458 type_stack.elements.pop_back ();
1459 return elt.typelist_val;
1462 /* Pop a type_stack element from the global type stack. */
1464 static struct type_stack *
1465 pop_type_stack (void)
1467 gdb_assert (!type_stack.elements.empty ());
1468 type_stack_elt elt = type_stack.elements.back ();
1469 type_stack.elements.pop_back ();
1470 return elt.stack_val;
1473 /* Append the elements of the type stack FROM to the type stack TO.
1474 Always returns TO. */
1477 append_type_stack (struct type_stack *to, struct type_stack *from)
1479 to->elements.insert (to->elements.end (), from->elements.begin (),
1480 from->elements.end ());
1484 /* Push the type stack STACK as an element on the global type stack. */
1487 push_type_stack (struct type_stack *stack)
1490 elt.stack_val = stack;
1491 type_stack.elements.push_back (elt);
1492 push_type (tp_type_stack);
1495 /* Copy the global type stack into a newly allocated type stack and
1496 return it. The global stack is cleared. The returned type stack
1497 must be freed with delete. */
1500 get_type_stack (void)
1502 struct type_stack *result = new struct type_stack (std::move (type_stack));
1503 type_stack.elements.clear ();
1507 /* Push a function type with arguments onto the global type stack.
1508 LIST holds the argument types. If the final item in LIST is NULL,
1509 then the function will be varargs. */
1512 push_typelist (std::vector<struct type *> *list)
1515 elt.typelist_val = list;
1516 type_stack.elements.push_back (elt);
1517 push_type (tp_function_with_arguments);
1520 /* Pop the type stack and return a type_instance_flags that
1521 corresponds the const/volatile qualifiers on the stack. This is
1522 called by the C++ parser when parsing methods types, and as such no
1523 other kind of type in the type stack is expected. */
1526 follow_type_instance_flags ()
1528 type_instance_flags flags = 0;
1531 switch (pop_type ())
1536 flags |= TYPE_INSTANCE_FLAG_CONST;
1539 flags |= TYPE_INSTANCE_FLAG_VOLATILE;
1542 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1547 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1548 as modified by all the stuff on the stack. */
1550 follow_types (struct type *follow_type)
1554 int make_volatile = 0;
1555 int make_addr_space = 0;
1559 switch (pop_type ())
1564 follow_type = make_cv_type (make_const,
1565 TYPE_VOLATILE (follow_type),
1568 follow_type = make_cv_type (TYPE_CONST (follow_type),
1571 if (make_addr_space)
1572 follow_type = make_type_with_address_space (follow_type,
1574 make_const = make_volatile = 0;
1575 make_addr_space = 0;
1583 case tp_space_identifier:
1584 make_addr_space = pop_type_int ();
1587 follow_type = lookup_pointer_type (follow_type);
1589 follow_type = make_cv_type (make_const,
1590 TYPE_VOLATILE (follow_type),
1593 follow_type = make_cv_type (TYPE_CONST (follow_type),
1596 if (make_addr_space)
1597 follow_type = make_type_with_address_space (follow_type,
1599 make_const = make_volatile = 0;
1600 make_addr_space = 0;
1603 follow_type = lookup_lvalue_reference_type (follow_type);
1604 goto process_reference;
1605 case tp_rvalue_reference:
1606 follow_type = lookup_rvalue_reference_type (follow_type);
1609 follow_type = make_cv_type (make_const,
1610 TYPE_VOLATILE (follow_type),
1613 follow_type = make_cv_type (TYPE_CONST (follow_type),
1616 if (make_addr_space)
1617 follow_type = make_type_with_address_space (follow_type,
1619 make_const = make_volatile = 0;
1620 make_addr_space = 0;
1623 array_size = pop_type_int ();
1624 /* FIXME-type-allocation: need a way to free this type when we are
1627 lookup_array_range_type (follow_type,
1628 0, array_size >= 0 ? array_size - 1 : 0);
1630 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type))
1634 /* FIXME-type-allocation: need a way to free this type when we are
1636 follow_type = lookup_function_type (follow_type);
1639 case tp_function_with_arguments:
1641 std::vector<struct type *> *args = pop_typelist ();
1644 = lookup_function_type_with_arguments (follow_type,
1652 struct type_stack *stack = pop_type_stack ();
1653 /* Sort of ugly, but not really much worse than the
1655 struct type_stack save = type_stack;
1657 type_stack = *stack;
1658 follow_type = follow_types (follow_type);
1659 gdb_assert (type_stack.elements.empty ());
1665 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1670 /* This function avoids direct calls to fprintf
1671 in the parser generated debug code. */
1673 parser_fprintf (FILE *x, const char *y, ...)
1679 vfprintf_unfiltered (gdb_stderr, y, args);
1682 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1683 vfprintf_unfiltered (gdb_stderr, y, args);
1688 /* Implementation of the exp_descriptor method operator_check. */
1691 operator_check_standard (struct expression *exp, int pos,
1692 int (*objfile_func) (struct objfile *objfile,
1696 const union exp_element *const elts = exp->elts;
1697 struct type *type = NULL;
1698 struct objfile *objfile = NULL;
1700 /* Extended operators should have been already handled by exp_descriptor
1701 iterate method of its specific language. */
1702 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1704 /* Track the callers of write_exp_elt_type for this table. */
1706 switch (elts[pos].opcode)
1718 type = elts[pos + 1].type;
1723 LONGEST arg, nargs = elts[pos + 2].longconst;
1725 for (arg = 0; arg < nargs; arg++)
1727 struct type *inst_type = elts[pos + 3 + arg].type;
1728 struct objfile *inst_objfile = TYPE_OBJFILE (inst_type);
1730 if (inst_objfile && (*objfile_func) (inst_objfile, data))
1738 const struct block *const block = elts[pos + 1].block;
1739 const struct symbol *const symbol = elts[pos + 2].symbol;
1741 /* Check objfile where the variable itself is placed.
1742 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1743 if ((*objfile_func) (symbol_objfile (symbol), data))
1746 /* Check objfile where is placed the code touching the variable. */
1747 objfile = lookup_objfile_from_block (block);
1749 type = SYMBOL_TYPE (symbol);
1752 case OP_VAR_MSYM_VALUE:
1753 objfile = elts[pos + 1].objfile;
1757 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1759 if (type && TYPE_OBJFILE (type)
1760 && (*objfile_func) (TYPE_OBJFILE (type), data))
1762 if (objfile && (*objfile_func) (objfile, data))
1768 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1769 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1770 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1771 returns non-zero value then (any other) non-zero value is immediately
1772 returned to the caller. Otherwise zero is returned after iterating
1773 through whole EXP. */
1776 exp_iterate (struct expression *exp,
1777 int (*objfile_func) (struct objfile *objfile, void *data),
1782 for (endpos = exp->nelts; endpos > 0; )
1784 int pos, args, oplen = 0;
1786 operator_length (exp, endpos, &oplen, &args);
1787 gdb_assert (oplen > 0);
1789 pos = endpos - oplen;
1790 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1791 objfile_func, data))
1800 /* Helper for exp_uses_objfile. */
1803 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1805 struct objfile *objfile = (struct objfile *) objfile_voidp;
1807 if (exp_objfile->separate_debug_objfile_backlink)
1808 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1810 return exp_objfile == objfile;
1813 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1814 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1818 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1820 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1822 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1825 /* See definition in parser-defs.h. */
1828 increase_expout_size (struct parser_state *ps, size_t lenelt)
1830 if ((ps->expout_ptr + lenelt) >= ps->expout_size)
1832 ps->expout_size = std::max (ps->expout_size * 2,
1833 ps->expout_ptr + lenelt + 10);
1834 ps->expout.reset (XRESIZEVAR (expression,
1835 ps->expout.release (),
1836 (sizeof (struct expression)
1837 + EXP_ELEM_TO_BYTES (ps->expout_size))));
1842 _initialize_parse (void)
1844 add_setshow_zuinteger_cmd ("expression", class_maintenance,
1846 _("Set expression debugging."),
1847 _("Show expression debugging."),
1848 _("When non-zero, the internal representation "
1849 "of expressions will be printed."),
1851 show_expressiondebug,
1852 &setdebuglist, &showdebuglist);
1853 add_setshow_boolean_cmd ("parser", class_maintenance,
1855 _("Set parser debugging."),
1856 _("Show parser debugging."),
1857 _("When non-zero, expression parser "
1858 "tracing will be enabled."),
1861 &setdebuglist, &showdebuglist);