1 /* Parse expressions for GDB.
3 Copyright (C) 1986-2018 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 static expression_up parse_exp_in_context_1 (const char **, CORE_ADDR,
121 const struct block *, int,
124 /* Documented at it's declaration. */
127 innermost_block_tracker::update (const struct block *b,
128 innermost_block_tracker_types t)
130 if ((m_types & t) != 0
131 && (m_innermost_block == NULL
132 || contained_in (b, m_innermost_block)))
133 m_innermost_block = b;
136 /* Data structure for saving values of arglist_len for function calls whose
137 arguments contain other function calls. */
139 static std::vector<int> *funcall_chain;
141 /* Begin counting arguments for a function call,
142 saving the data about any containing call. */
147 funcall_chain->push_back (arglist_len);
151 /* Return the number of arguments in a function call just terminated,
152 and restore the data for the containing function call. */
157 int val = arglist_len;
158 arglist_len = funcall_chain->back ();
159 funcall_chain->pop_back ();
165 /* See definition in parser-defs.h. */
167 parser_state::parser_state (size_t initial_size,
168 const struct language_defn *lang,
169 struct gdbarch *gdbarch)
170 : expout_size (initial_size),
171 expout (XNEWVAR (expression,
173 + EXP_ELEM_TO_BYTES (expout_size)))),
176 expout->language_defn = lang;
177 expout->gdbarch = gdbarch;
181 parser_state::release ()
183 /* Record the actual number of expression elements, and then
184 reallocate the expression memory so that we free up any
187 expout->nelts = expout_ptr;
188 expout.reset (XRESIZEVAR (expression, expout.release (),
190 + EXP_ELEM_TO_BYTES (expout_ptr))));
192 return std::move (expout);
195 /* This page contains the functions for adding data to the struct expression
196 being constructed. */
198 /* Add one element to the end of the expression. */
200 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
201 a register through here. */
204 write_exp_elt (struct parser_state *ps, const union exp_element *expelt)
206 if (ps->expout_ptr >= ps->expout_size)
208 ps->expout_size *= 2;
209 ps->expout.reset (XRESIZEVAR (expression, ps->expout.release (),
211 + EXP_ELEM_TO_BYTES (ps->expout_size))));
213 ps->expout->elts[ps->expout_ptr++] = *expelt;
217 write_exp_elt_opcode (struct parser_state *ps, enum exp_opcode expelt)
219 union exp_element tmp;
221 memset (&tmp, 0, sizeof (union exp_element));
223 write_exp_elt (ps, &tmp);
227 write_exp_elt_sym (struct parser_state *ps, struct symbol *expelt)
229 union exp_element tmp;
231 memset (&tmp, 0, sizeof (union exp_element));
233 write_exp_elt (ps, &tmp);
237 write_exp_elt_msym (struct parser_state *ps, minimal_symbol *expelt)
239 union exp_element tmp;
241 memset (&tmp, 0, sizeof (union exp_element));
242 tmp.msymbol = expelt;
243 write_exp_elt (ps, &tmp);
247 write_exp_elt_block (struct parser_state *ps, const struct block *b)
249 union exp_element tmp;
251 memset (&tmp, 0, sizeof (union exp_element));
253 write_exp_elt (ps, &tmp);
257 write_exp_elt_objfile (struct parser_state *ps, struct objfile *objfile)
259 union exp_element tmp;
261 memset (&tmp, 0, sizeof (union exp_element));
262 tmp.objfile = objfile;
263 write_exp_elt (ps, &tmp);
267 write_exp_elt_longcst (struct parser_state *ps, LONGEST expelt)
269 union exp_element tmp;
271 memset (&tmp, 0, sizeof (union exp_element));
272 tmp.longconst = expelt;
273 write_exp_elt (ps, &tmp);
277 write_exp_elt_floatcst (struct parser_state *ps, const gdb_byte expelt[16])
279 union exp_element tmp;
282 for (index = 0; index < 16; index++)
283 tmp.floatconst[index] = expelt[index];
285 write_exp_elt (ps, &tmp);
289 write_exp_elt_type (struct parser_state *ps, struct type *expelt)
291 union exp_element tmp;
293 memset (&tmp, 0, sizeof (union exp_element));
295 write_exp_elt (ps, &tmp);
299 write_exp_elt_intern (struct parser_state *ps, struct internalvar *expelt)
301 union exp_element tmp;
303 memset (&tmp, 0, sizeof (union exp_element));
304 tmp.internalvar = expelt;
305 write_exp_elt (ps, &tmp);
308 /* Add a string constant to the end of the expression.
310 String constants are stored by first writing an expression element
311 that contains the length of the string, then stuffing the string
312 constant itself into however many expression elements are needed
313 to hold it, and then writing another expression element that contains
314 the length of the string. I.e. an expression element at each end of
315 the string records the string length, so you can skip over the
316 expression elements containing the actual string bytes from either
317 end of the string. Note that this also allows gdb to handle
318 strings with embedded null bytes, as is required for some languages.
320 Don't be fooled by the fact that the string is null byte terminated,
321 this is strictly for the convenience of debugging gdb itself.
322 Gdb does not depend up the string being null terminated, since the
323 actual length is recorded in expression elements at each end of the
324 string. The null byte is taken into consideration when computing how
325 many expression elements are required to hold the string constant, of
330 write_exp_string (struct parser_state *ps, struct stoken str)
332 int len = str.length;
336 /* Compute the number of expression elements required to hold the string
337 (including a null byte terminator), along with one expression element
338 at each end to record the actual string length (not including the
339 null byte terminator). */
341 lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);
343 increase_expout_size (ps, lenelt);
345 /* Write the leading length expression element (which advances the current
346 expression element index), then write the string constant followed by a
347 terminating null byte, and then write the trailing length expression
350 write_exp_elt_longcst (ps, (LONGEST) len);
351 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
352 memcpy (strdata, str.ptr, len);
353 *(strdata + len) = '\0';
354 ps->expout_ptr += lenelt - 2;
355 write_exp_elt_longcst (ps, (LONGEST) len);
358 /* Add a vector of string constants to the end of the expression.
360 This adds an OP_STRING operation, but encodes the contents
361 differently from write_exp_string. The language is expected to
362 handle evaluation of this expression itself.
364 After the usual OP_STRING header, TYPE is written into the
365 expression as a long constant. The interpretation of this field is
366 up to the language evaluator.
368 Next, each string in VEC is written. The length is written as a
369 long constant, followed by the contents of the string. */
372 write_exp_string_vector (struct parser_state *ps, int type,
373 struct stoken_vector *vec)
378 /* Compute the size. We compute the size in number of slots to
379 avoid issues with string padding. */
381 for (i = 0; i < vec->len; ++i)
383 /* One slot for the length of this element, plus the number of
384 slots needed for this string. */
385 n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
388 /* One more slot for the type of the string. */
391 /* Now compute a phony string length. */
392 len = EXP_ELEM_TO_BYTES (n_slots) - 1;
395 increase_expout_size (ps, n_slots);
397 write_exp_elt_opcode (ps, OP_STRING);
398 write_exp_elt_longcst (ps, len);
399 write_exp_elt_longcst (ps, type);
401 for (i = 0; i < vec->len; ++i)
403 write_exp_elt_longcst (ps, vec->tokens[i].length);
404 memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr,
405 vec->tokens[i].length);
406 ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
409 write_exp_elt_longcst (ps, len);
410 write_exp_elt_opcode (ps, OP_STRING);
413 /* Add a bitstring constant to the end of the expression.
415 Bitstring constants are stored by first writing an expression element
416 that contains the length of the bitstring (in bits), then stuffing the
417 bitstring constant itself into however many expression elements are
418 needed to hold it, and then writing another expression element that
419 contains the length of the bitstring. I.e. an expression element at
420 each end of the bitstring records the bitstring length, so you can skip
421 over the expression elements containing the actual bitstring bytes from
422 either end of the bitstring. */
425 write_exp_bitstring (struct parser_state *ps, struct stoken str)
427 int bits = str.length; /* length in bits */
428 int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
432 /* Compute the number of expression elements required to hold the bitstring,
433 along with one expression element at each end to record the actual
434 bitstring length in bits. */
436 lenelt = 2 + BYTES_TO_EXP_ELEM (len);
438 increase_expout_size (ps, lenelt);
440 /* Write the leading length expression element (which advances the current
441 expression element index), then write the bitstring constant, and then
442 write the trailing length expression element. */
444 write_exp_elt_longcst (ps, (LONGEST) bits);
445 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
446 memcpy (strdata, str.ptr, len);
447 ps->expout_ptr += lenelt - 2;
448 write_exp_elt_longcst (ps, (LONGEST) bits);
451 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
452 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
456 find_minsym_type_and_address (minimal_symbol *msymbol,
457 struct objfile *objfile,
458 CORE_ADDR *address_p)
460 bound_minimal_symbol bound_msym = {msymbol, objfile};
461 struct gdbarch *gdbarch = get_objfile_arch (objfile);
462 struct obj_section *section = MSYMBOL_OBJ_SECTION (objfile, msymbol);
463 enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
466 bool is_tls = (section != NULL
467 && section->the_bfd_section->flags & SEC_THREAD_LOCAL);
469 /* Addresses of TLS symbols are really offsets into a
470 per-objfile/per-thread storage block. */
471 CORE_ADDR addr = (is_tls
472 ? MSYMBOL_VALUE_RAW_ADDRESS (bound_msym.minsym)
473 : BMSYMBOL_VALUE_ADDRESS (bound_msym));
475 /* The minimal symbol might point to a function descriptor;
476 resolve it to the actual code address instead. */
477 pc = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, ¤t_target);
480 struct bound_minimal_symbol ifunc_msym = lookup_minimal_symbol_by_pc (pc);
482 /* In this case, assume we have a code symbol instead of
485 if (ifunc_msym.minsym != NULL
486 && MSYMBOL_TYPE (ifunc_msym.minsym) == mst_text_gnu_ifunc
487 && BMSYMBOL_VALUE_ADDRESS (ifunc_msym) == pc)
489 /* A function descriptor has been resolved but PC is still in the
490 STT_GNU_IFUNC resolver body (such as because inferior does not
491 run to be able to call it). */
493 type = mst_text_gnu_ifunc;
501 if (overlay_debugging)
502 addr = symbol_overlayed_address (addr, section);
506 /* Skip translation if caller does not need the address. */
507 if (address_p != NULL)
508 *address_p = target_translate_tls_address (objfile, addr);
509 return objfile_type (objfile)->nodebug_tls_symbol;
512 if (address_p != NULL)
519 case mst_solib_trampoline:
520 return objfile_type (objfile)->nodebug_text_symbol;
522 case mst_text_gnu_ifunc:
523 return objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
529 return objfile_type (objfile)->nodebug_data_symbol;
531 case mst_slot_got_plt:
532 return objfile_type (objfile)->nodebug_got_plt_symbol;
535 return objfile_type (objfile)->nodebug_unknown_symbol;
539 /* Add the appropriate elements for a minimal symbol to the end of
543 write_exp_msymbol (struct parser_state *ps,
544 struct bound_minimal_symbol bound_msym)
546 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
547 write_exp_elt_objfile (ps, bound_msym.objfile);
548 write_exp_elt_msym (ps, bound_msym.minsym);
549 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
552 /* Mark the current index as the starting location of a structure
553 expression. This is used when completing on field names. */
556 mark_struct_expression (struct parser_state *ps)
558 gdb_assert (parse_completion
559 && expout_tag_completion_type == TYPE_CODE_UNDEF);
560 expout_last_struct = ps->expout_ptr;
563 /* Indicate that the current parser invocation is completing a tag.
564 TAG is the type code of the tag, and PTR and LENGTH represent the
565 start of the tag name. */
568 mark_completion_tag (enum type_code tag, const char *ptr, int length)
570 gdb_assert (parse_completion
571 && expout_tag_completion_type == TYPE_CODE_UNDEF
572 && expout_completion_name == NULL
573 && expout_last_struct == -1);
574 gdb_assert (tag == TYPE_CODE_UNION
575 || tag == TYPE_CODE_STRUCT
576 || tag == TYPE_CODE_ENUM);
577 expout_tag_completion_type = tag;
578 expout_completion_name.reset (xstrndup (ptr, length));
582 /* Recognize tokens that start with '$'. These include:
584 $regname A native register name or a "standard
587 $variable A convenience variable with a name chosen
590 $digits Value history with index <digits>, starting
591 from the first value which has index 1.
593 $$digits Value history with index <digits> relative
594 to the last value. I.e. $$0 is the last
595 value, $$1 is the one previous to that, $$2
596 is the one previous to $$1, etc.
598 $ | $0 | $$0 The last value in the value history.
600 $$ An abbreviation for the second to the last
601 value in the value history, I.e. $$1 */
604 write_dollar_variable (struct parser_state *ps, struct stoken str)
606 struct block_symbol sym;
607 struct bound_minimal_symbol msym;
608 struct internalvar *isym = NULL;
610 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
611 and $$digits (equivalent to $<-digits> if you could type that). */
615 /* Double dollar means negate the number and add -1 as well.
616 Thus $$ alone means -1. */
617 if (str.length >= 2 && str.ptr[1] == '$')
624 /* Just dollars (one or two). */
628 /* Is the rest of the token digits? */
629 for (; i < str.length; i++)
630 if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
634 i = atoi (str.ptr + 1 + negate);
640 /* Handle tokens that refer to machine registers:
641 $ followed by a register name. */
642 i = user_reg_map_name_to_regnum (parse_gdbarch (ps),
643 str.ptr + 1, str.length - 1);
645 goto handle_register;
647 /* Any names starting with $ are probably debugger internal variables. */
649 isym = lookup_only_internalvar (copy_name (str) + 1);
652 write_exp_elt_opcode (ps, OP_INTERNALVAR);
653 write_exp_elt_intern (ps, isym);
654 write_exp_elt_opcode (ps, OP_INTERNALVAR);
658 /* On some systems, such as HP-UX and hppa-linux, certain system routines
659 have names beginning with $ or $$. Check for those, first. */
661 sym = lookup_symbol (copy_name (str), (struct block *) NULL,
665 write_exp_elt_opcode (ps, OP_VAR_VALUE);
666 write_exp_elt_block (ps, sym.block);
667 write_exp_elt_sym (ps, sym.symbol);
668 write_exp_elt_opcode (ps, OP_VAR_VALUE);
671 msym = lookup_bound_minimal_symbol (copy_name (str));
674 write_exp_msymbol (ps, msym);
678 /* Any other names are assumed to be debugger internal variables. */
680 write_exp_elt_opcode (ps, OP_INTERNALVAR);
681 write_exp_elt_intern (ps, create_internalvar (copy_name (str) + 1));
682 write_exp_elt_opcode (ps, OP_INTERNALVAR);
685 write_exp_elt_opcode (ps, OP_LAST);
686 write_exp_elt_longcst (ps, (LONGEST) i);
687 write_exp_elt_opcode (ps, OP_LAST);
690 write_exp_elt_opcode (ps, OP_REGISTER);
693 write_exp_string (ps, str);
694 write_exp_elt_opcode (ps, OP_REGISTER);
695 innermost_block.update (expression_context_block,
696 INNERMOST_BLOCK_FOR_REGISTERS);
702 find_template_name_end (const char *p)
705 int just_seen_right = 0;
706 int just_seen_colon = 0;
707 int just_seen_space = 0;
709 if (!p || (*p != '<'))
720 /* In future, may want to allow these?? */
723 depth++; /* start nested template */
724 if (just_seen_colon || just_seen_right || just_seen_space)
725 return 0; /* but not after : or :: or > or space */
728 if (just_seen_colon || just_seen_right)
729 return 0; /* end a (nested?) template */
730 just_seen_right = 1; /* but not after : or :: */
731 if (--depth == 0) /* also disallow >>, insist on > > */
732 return ++p; /* if outermost ended, return */
735 if (just_seen_space || (just_seen_colon > 1))
736 return 0; /* nested class spec coming up */
737 just_seen_colon++; /* we allow :: but not :::: */
742 if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
743 (*p >= 'A' && *p <= 'Z') ||
744 (*p >= '0' && *p <= '9') ||
745 (*p == '_') || (*p == ',') || /* commas for template args */
746 (*p == '&') || (*p == '*') || /* pointer and ref types */
747 (*p == '(') || (*p == ')') || /* function types */
748 (*p == '[') || (*p == ']'))) /* array types */
762 /* Return a null-terminated temporary copy of the name of a string token.
764 Tokens that refer to names do so with explicit pointer and length,
765 so they can share the storage that lexptr is parsing.
766 When it is necessary to pass a name to a function that expects
767 a null-terminated string, the substring is copied out
768 into a separate block of storage.
770 N.B. A single buffer is reused on each call. */
773 copy_name (struct stoken token)
775 /* A temporary buffer for identifiers, so we can null-terminate them.
776 We allocate this with xrealloc. parse_exp_1 used to allocate with
777 alloca, using the size of the whole expression as a conservative
778 estimate of the space needed. However, macro expansion can
779 introduce names longer than the original expression; there's no
780 practical way to know beforehand how large that might be. */
781 static char *namecopy;
782 static size_t namecopy_size;
784 /* Make sure there's enough space for the token. */
785 if (namecopy_size < token.length + 1)
787 namecopy_size = token.length + 1;
788 namecopy = (char *) xrealloc (namecopy, token.length + 1);
791 memcpy (namecopy, token.ptr, token.length);
792 namecopy[token.length] = 0;
798 /* See comments on parser-defs.h. */
801 prefixify_expression (struct expression *expr)
803 int len = sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts);
804 struct expression *temp;
805 int inpos = expr->nelts, outpos = 0;
807 temp = (struct expression *) alloca (len);
809 /* Copy the original expression into temp. */
810 memcpy (temp, expr, len);
812 return prefixify_subexp (temp, expr, inpos, outpos);
815 /* Return the number of exp_elements in the postfix subexpression
816 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
819 length_of_subexp (struct expression *expr, int endpos)
823 operator_length (expr, endpos, &oplen, &args);
827 oplen += length_of_subexp (expr, endpos - oplen);
834 /* Sets *OPLENP to the length of the operator whose (last) index is
835 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
839 operator_length (const struct expression *expr, int endpos, int *oplenp,
842 expr->language_defn->la_exp_desc->operator_length (expr, endpos,
846 /* Default value for operator_length in exp_descriptor vectors. */
849 operator_length_standard (const struct expression *expr, int endpos,
850 int *oplenp, int *argsp)
854 enum range_type range_type;
858 error (_("?error in operator_length_standard"));
860 i = (int) expr->elts[endpos - 1].opcode;
866 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
867 oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
873 case OP_VAR_MSYM_VALUE:
877 case OP_FUNC_STATIC_VAR:
878 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
879 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
887 case OP_VAR_ENTRY_VALUE:
897 case OP_F77_UNDETERMINED_ARGLIST:
899 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
903 oplen = 5 + longest_to_int (expr->elts[endpos - 2].longconst);
907 case OP_OBJC_MSGCALL: /* Objective C message (method) call. */
909 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
918 case UNOP_DYNAMIC_CAST:
919 case UNOP_REINTERPRET_CAST:
920 case UNOP_MEMVAL_TYPE:
948 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
949 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
954 case STRUCTOP_STRUCT:
961 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
962 NSString constant. */
963 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
965 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
966 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
971 args = longest_to_int (expr->elts[endpos - 2].longconst);
972 args -= longest_to_int (expr->elts[endpos - 3].longconst);
982 case MULTI_SUBSCRIPT:
984 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
987 case BINOP_ASSIGN_MODIFY:
999 range_type = (enum range_type)
1000 longest_to_int (expr->elts[endpos - 2].longconst);
1004 case LOW_BOUND_DEFAULT:
1005 case HIGH_BOUND_DEFAULT:
1008 case BOTH_BOUND_DEFAULT:
1011 case NONE_BOUND_DEFAULT:
1019 args = 1 + (i < (int) BINOP_END);
1026 /* Copy the subexpression ending just before index INEND in INEXPR
1027 into OUTEXPR, starting at index OUTBEG.
1028 In the process, convert it from suffix to prefix form.
1029 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1030 Otherwise, it returns the index of the subexpression which is the
1031 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1034 prefixify_subexp (struct expression *inexpr,
1035 struct expression *outexpr, int inend, int outbeg)
1043 operator_length (inexpr, inend, &oplen, &args);
1045 /* Copy the final operator itself, from the end of the input
1046 to the beginning of the output. */
1048 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1049 EXP_ELEM_TO_BYTES (oplen));
1052 if (expout_last_struct == inend)
1053 result = outbeg - oplen;
1055 /* Find the lengths of the arg subexpressions. */
1056 arglens = (int *) alloca (args * sizeof (int));
1057 for (i = args - 1; i >= 0; i--)
1059 oplen = length_of_subexp (inexpr, inend);
1064 /* Now copy each subexpression, preserving the order of
1065 the subexpressions, but prefixifying each one.
1066 In this loop, inend starts at the beginning of
1067 the expression this level is working on
1068 and marches forward over the arguments.
1069 outbeg does similarly in the output. */
1070 for (i = 0; i < args; i++)
1076 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1079 /* Return immediately. We probably have only parsed a
1080 partial expression, so we don't want to try to reverse
1081 the other operands. */
1090 /* Read an expression from the string *STRINGPTR points to,
1091 parse it, and return a pointer to a struct expression that we malloc.
1092 Use block BLOCK as the lexical context for variable names;
1093 if BLOCK is zero, use the block of the selected stack frame.
1094 Meanwhile, advance *STRINGPTR to point after the expression,
1095 at the first nonwhite character that is not part of the expression
1096 (possibly a null character).
1098 If COMMA is nonzero, stop if a comma is reached. */
1101 parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
1104 return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL);
1107 static expression_up
1108 parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
1109 const struct block *block,
1110 int comma, int void_context_p, int *out_subexp)
1112 return parse_exp_in_context_1 (stringptr, pc, block, comma,
1113 void_context_p, out_subexp);
1116 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1117 no value is expected from the expression.
1118 OUT_SUBEXP is set when attempting to complete a field name; in this
1119 case it is set to the index of the subexpression on the
1120 left-hand-side of the struct op. If not doing such completion, it
1121 is left untouched. */
1123 static expression_up
1124 parse_exp_in_context_1 (const char **stringptr, CORE_ADDR pc,
1125 const struct block *block,
1126 int comma, int void_context_p, int *out_subexp)
1128 const struct language_defn *lang = NULL;
1131 lexptr = *stringptr;
1135 type_stack.depth = 0;
1136 expout_last_struct = -1;
1137 expout_tag_completion_type = TYPE_CODE_UNDEF;
1138 expout_completion_name.reset ();
1140 comma_terminates = comma;
1142 if (lexptr == 0 || *lexptr == 0)
1143 error_no_arg (_("expression to compute"));
1145 std::vector<int> funcalls;
1146 scoped_restore save_funcall_chain = make_scoped_restore (&funcall_chain,
1149 expression_context_block = block;
1151 /* If no context specified, try using the current frame, if any. */
1152 if (!expression_context_block)
1153 expression_context_block = get_selected_block (&expression_context_pc);
1155 expression_context_pc = BLOCK_START (expression_context_block);
1157 expression_context_pc = pc;
1159 /* Fall back to using the current source static context, if any. */
1161 if (!expression_context_block)
1163 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1165 expression_context_block
1166 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
1168 if (expression_context_block)
1169 expression_context_pc = BLOCK_START (expression_context_block);
1172 if (language_mode == language_mode_auto && block != NULL)
1174 /* Find the language associated to the given context block.
1175 Default to the current language if it can not be determined.
1177 Note that using the language corresponding to the current frame
1178 can sometimes give unexpected results. For instance, this
1179 routine is often called several times during the inferior
1180 startup phase to re-parse breakpoint expressions after
1181 a new shared library has been loaded. The language associated
1182 to the current frame at this moment is not relevant for
1183 the breakpoint. Using it would therefore be silly, so it seems
1184 better to rely on the current language rather than relying on
1185 the current frame language to parse the expression. That's why
1186 we do the following language detection only if the context block
1187 has been specifically provided. */
1188 struct symbol *func = block_linkage_function (block);
1191 lang = language_def (SYMBOL_LANGUAGE (func));
1192 if (lang == NULL || lang->la_language == language_unknown)
1193 lang = current_language;
1196 lang = current_language;
1198 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1199 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1200 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1201 to the value matching SELECTED_FRAME as set by get_current_arch. */
1203 parser_state ps (10, lang, get_current_arch ());
1205 scoped_restore_current_language lang_saver;
1206 set_language (lang->la_language);
1210 if (lang->la_parser (&ps))
1211 lang->la_error (NULL);
1213 CATCH (except, RETURN_MASK_ALL)
1215 if (! parse_completion)
1216 throw_exception (except);
1220 /* We have to operate on an "expression *", due to la_post_parser,
1221 which explains this funny-looking double release. */
1222 expression_up result = ps.release ();
1224 /* Convert expression from postfix form as generated by yacc
1225 parser, to a prefix form. */
1227 if (expressiondebug)
1228 dump_raw_expression (result.get (), gdb_stdlog,
1229 "before conversion to prefix form");
1231 subexp = prefixify_expression (result.get ());
1233 *out_subexp = subexp;
1235 lang->la_post_parser (&result, void_context_p);
1237 if (expressiondebug)
1238 dump_prefix_expression (result.get (), gdb_stdlog);
1240 *stringptr = lexptr;
1244 /* Parse STRING as an expression, and complain if this fails
1245 to use up all of the contents of STRING. */
1248 parse_expression (const char *string)
1250 expression_up exp = parse_exp_1 (&string, 0, 0, 0);
1252 error (_("Junk after end of expression."));
1256 /* Same as parse_expression, but using the given language (LANG)
1257 to parse the expression. */
1260 parse_expression_with_language (const char *string, enum language lang)
1262 gdb::optional<scoped_restore_current_language> lang_saver;
1263 if (current_language->la_language != lang)
1265 lang_saver.emplace ();
1266 set_language (lang);
1269 return parse_expression (string);
1272 /* Parse STRING as an expression. If parsing ends in the middle of a
1273 field reference, return the type of the left-hand-side of the
1274 reference; furthermore, if the parsing ends in the field name,
1275 return the field name in *NAME. If the parsing ends in the middle
1276 of a field reference, but the reference is somehow invalid, throw
1277 an exception. In all other cases, return NULL. */
1280 parse_expression_for_completion (const char *string,
1281 gdb::unique_xmalloc_ptr<char> *name,
1282 enum type_code *code)
1290 parse_completion = 1;
1291 exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp);
1293 CATCH (except, RETURN_MASK_ERROR)
1295 /* Nothing, EXP remains NULL. */
1299 parse_completion = 0;
1303 if (expout_tag_completion_type != TYPE_CODE_UNDEF)
1305 *code = expout_tag_completion_type;
1306 *name = std::move (expout_completion_name);
1310 if (expout_last_struct == -1)
1313 const char *fieldname = extract_field_op (exp.get (), &subexp);
1314 if (fieldname == NULL)
1320 name->reset (xstrdup (fieldname));
1321 /* This might throw an exception. If so, we want to let it
1323 val = evaluate_subexpression_type (exp.get (), subexp);
1325 return value_type (val);
1328 /* A post-parser that does nothing. */
1331 null_post_parser (expression_up *exp, int void_context_p)
1335 /* Parse floating point value P of length LEN.
1336 Return false if invalid, true if valid.
1337 The successfully parsed number is stored in DATA in
1338 target format for floating-point type TYPE.
1340 NOTE: This accepts the floating point syntax that sscanf accepts. */
1343 parse_float (const char *p, int len,
1344 const struct type *type, gdb_byte *data)
1346 return target_float_from_string (data, type, std::string (p, len));
1349 /* Stuff for maintaining a stack of types. Currently just used by C, but
1350 probably useful for any language which declares its types "backwards". */
1352 /* Ensure that there are HOWMUCH open slots on the type stack STACK. */
1355 type_stack_reserve (struct type_stack *stack, int howmuch)
1357 if (stack->depth + howmuch >= stack->size)
1360 if (stack->size < howmuch)
1361 stack->size = howmuch;
1362 stack->elements = XRESIZEVEC (union type_stack_elt, stack->elements,
1367 /* Ensure that there is a single open slot in the global type stack. */
1370 check_type_stack_depth (void)
1372 type_stack_reserve (&type_stack, 1);
1375 /* A helper function for insert_type and insert_type_address_space.
1376 This does work of expanding the type stack and inserting the new
1377 element, ELEMENT, into the stack at location SLOT. */
1380 insert_into_type_stack (int slot, union type_stack_elt element)
1382 check_type_stack_depth ();
1384 if (slot < type_stack.depth)
1385 memmove (&type_stack.elements[slot + 1], &type_stack.elements[slot],
1386 (type_stack.depth - slot) * sizeof (union type_stack_elt));
1387 type_stack.elements[slot] = element;
1391 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1392 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1393 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1394 previous tp_pointer) if there is anything on the stack, or simply pushed
1395 if the stack is empty. Other values for TP are invalid. */
1398 insert_type (enum type_pieces tp)
1400 union type_stack_elt element;
1403 gdb_assert (tp == tp_pointer || tp == tp_reference
1404 || tp == tp_rvalue_reference || tp == tp_const
1405 || tp == tp_volatile);
1407 /* If there is anything on the stack (we know it will be a
1408 tp_pointer), insert the qualifier above it. Otherwise, simply
1409 push this on the top of the stack. */
1410 if (type_stack.depth && (tp == tp_const || tp == tp_volatile))
1416 insert_into_type_stack (slot, element);
1420 push_type (enum type_pieces tp)
1422 check_type_stack_depth ();
1423 type_stack.elements[type_stack.depth++].piece = tp;
1427 push_type_int (int n)
1429 check_type_stack_depth ();
1430 type_stack.elements[type_stack.depth++].int_val = n;
1433 /* Insert a tp_space_identifier and the corresponding address space
1434 value into the stack. STRING is the name of an address space, as
1435 recognized by address_space_name_to_int. If the stack is empty,
1436 the new elements are simply pushed. If the stack is not empty,
1437 this function assumes that the first item on the stack is a
1438 tp_pointer, and the new values are inserted above the first
1442 insert_type_address_space (struct parser_state *pstate, char *string)
1444 union type_stack_elt element;
1447 /* If there is anything on the stack (we know it will be a
1448 tp_pointer), insert the address space qualifier above it.
1449 Otherwise, simply push this on the top of the stack. */
1450 if (type_stack.depth)
1455 element.piece = tp_space_identifier;
1456 insert_into_type_stack (slot, element);
1457 element.int_val = address_space_name_to_int (parse_gdbarch (pstate),
1459 insert_into_type_stack (slot, element);
1465 if (type_stack.depth)
1466 return type_stack.elements[--type_stack.depth].piece;
1473 if (type_stack.depth)
1474 return type_stack.elements[--type_stack.depth].int_val;
1475 /* "Can't happen". */
1479 /* Pop a type list element from the global type stack. */
1481 static VEC (type_ptr) *
1484 gdb_assert (type_stack.depth);
1485 return type_stack.elements[--type_stack.depth].typelist_val;
1488 /* Pop a type_stack element from the global type stack. */
1490 static struct type_stack *
1491 pop_type_stack (void)
1493 gdb_assert (type_stack.depth);
1494 return type_stack.elements[--type_stack.depth].stack_val;
1497 /* Append the elements of the type stack FROM to the type stack TO.
1498 Always returns TO. */
1501 append_type_stack (struct type_stack *to, struct type_stack *from)
1503 type_stack_reserve (to, from->depth);
1505 memcpy (&to->elements[to->depth], &from->elements[0],
1506 from->depth * sizeof (union type_stack_elt));
1507 to->depth += from->depth;
1512 /* Push the type stack STACK as an element on the global type stack. */
1515 push_type_stack (struct type_stack *stack)
1517 check_type_stack_depth ();
1518 type_stack.elements[type_stack.depth++].stack_val = stack;
1519 push_type (tp_type_stack);
1522 /* Copy the global type stack into a newly allocated type stack and
1523 return it. The global stack is cleared. The returned type stack
1524 must be freed with type_stack_cleanup. */
1527 get_type_stack (void)
1529 struct type_stack *result = XNEW (struct type_stack);
1531 *result = type_stack;
1532 type_stack.depth = 0;
1533 type_stack.size = 0;
1534 type_stack.elements = NULL;
1539 /* A cleanup function that destroys a single type stack. */
1542 type_stack_cleanup (void *arg)
1544 struct type_stack *stack = (struct type_stack *) arg;
1546 xfree (stack->elements);
1550 /* Push a function type with arguments onto the global type stack.
1551 LIST holds the argument types. If the final item in LIST is NULL,
1552 then the function will be varargs. */
1555 push_typelist (VEC (type_ptr) *list)
1557 check_type_stack_depth ();
1558 type_stack.elements[type_stack.depth++].typelist_val = list;
1559 push_type (tp_function_with_arguments);
1562 /* Pop the type stack and return a type_instance_flags that
1563 corresponds the const/volatile qualifiers on the stack. This is
1564 called by the C++ parser when parsing methods types, and as such no
1565 other kind of type in the type stack is expected. */
1568 follow_type_instance_flags ()
1570 type_instance_flags flags = 0;
1573 switch (pop_type ())
1578 flags |= TYPE_INSTANCE_FLAG_CONST;
1581 flags |= TYPE_INSTANCE_FLAG_VOLATILE;
1584 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1589 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1590 as modified by all the stuff on the stack. */
1592 follow_types (struct type *follow_type)
1596 int make_volatile = 0;
1597 int make_addr_space = 0;
1601 switch (pop_type ())
1606 follow_type = make_cv_type (make_const,
1607 TYPE_VOLATILE (follow_type),
1610 follow_type = make_cv_type (TYPE_CONST (follow_type),
1613 if (make_addr_space)
1614 follow_type = make_type_with_address_space (follow_type,
1616 make_const = make_volatile = 0;
1617 make_addr_space = 0;
1625 case tp_space_identifier:
1626 make_addr_space = pop_type_int ();
1629 follow_type = lookup_pointer_type (follow_type);
1631 follow_type = make_cv_type (make_const,
1632 TYPE_VOLATILE (follow_type),
1635 follow_type = make_cv_type (TYPE_CONST (follow_type),
1638 if (make_addr_space)
1639 follow_type = make_type_with_address_space (follow_type,
1641 make_const = make_volatile = 0;
1642 make_addr_space = 0;
1645 follow_type = lookup_lvalue_reference_type (follow_type);
1646 goto process_reference;
1647 case tp_rvalue_reference:
1648 follow_type = lookup_rvalue_reference_type (follow_type);
1651 follow_type = make_cv_type (make_const,
1652 TYPE_VOLATILE (follow_type),
1655 follow_type = make_cv_type (TYPE_CONST (follow_type),
1658 if (make_addr_space)
1659 follow_type = make_type_with_address_space (follow_type,
1661 make_const = make_volatile = 0;
1662 make_addr_space = 0;
1665 array_size = pop_type_int ();
1666 /* FIXME-type-allocation: need a way to free this type when we are
1669 lookup_array_range_type (follow_type,
1670 0, array_size >= 0 ? array_size - 1 : 0);
1672 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type))
1676 /* FIXME-type-allocation: need a way to free this type when we are
1678 follow_type = lookup_function_type (follow_type);
1681 case tp_function_with_arguments:
1683 VEC (type_ptr) *args = pop_typelist ();
1686 = lookup_function_type_with_arguments (follow_type,
1687 VEC_length (type_ptr, args),
1688 VEC_address (type_ptr,
1690 VEC_free (type_ptr, args);
1696 struct type_stack *stack = pop_type_stack ();
1697 /* Sort of ugly, but not really much worse than the
1699 struct type_stack save = type_stack;
1701 type_stack = *stack;
1702 follow_type = follow_types (follow_type);
1703 gdb_assert (type_stack.depth == 0);
1709 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1714 /* This function avoids direct calls to fprintf
1715 in the parser generated debug code. */
1717 parser_fprintf (FILE *x, const char *y, ...)
1723 vfprintf_unfiltered (gdb_stderr, y, args);
1726 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1727 vfprintf_unfiltered (gdb_stderr, y, args);
1732 /* Implementation of the exp_descriptor method operator_check. */
1735 operator_check_standard (struct expression *exp, int pos,
1736 int (*objfile_func) (struct objfile *objfile,
1740 const union exp_element *const elts = exp->elts;
1741 struct type *type = NULL;
1742 struct objfile *objfile = NULL;
1744 /* Extended operators should have been already handled by exp_descriptor
1745 iterate method of its specific language. */
1746 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1748 /* Track the callers of write_exp_elt_type for this table. */
1750 switch (elts[pos].opcode)
1762 type = elts[pos + 1].type;
1767 LONGEST arg, nargs = elts[pos + 2].longconst;
1769 for (arg = 0; arg < nargs; arg++)
1771 struct type *type = elts[pos + 3 + arg].type;
1772 struct objfile *objfile = TYPE_OBJFILE (type);
1774 if (objfile && (*objfile_func) (objfile, data))
1782 const struct block *const block = elts[pos + 1].block;
1783 const struct symbol *const symbol = elts[pos + 2].symbol;
1785 /* Check objfile where the variable itself is placed.
1786 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1787 if ((*objfile_func) (symbol_objfile (symbol), data))
1790 /* Check objfile where is placed the code touching the variable. */
1791 objfile = lookup_objfile_from_block (block);
1793 type = SYMBOL_TYPE (symbol);
1796 case OP_VAR_MSYM_VALUE:
1797 objfile = elts[pos + 1].objfile;
1801 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1803 if (type && TYPE_OBJFILE (type)
1804 && (*objfile_func) (TYPE_OBJFILE (type), data))
1806 if (objfile && (*objfile_func) (objfile, data))
1812 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1813 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1814 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1815 returns non-zero value then (any other) non-zero value is immediately
1816 returned to the caller. Otherwise zero is returned after iterating
1817 through whole EXP. */
1820 exp_iterate (struct expression *exp,
1821 int (*objfile_func) (struct objfile *objfile, void *data),
1826 for (endpos = exp->nelts; endpos > 0; )
1828 int pos, args, oplen = 0;
1830 operator_length (exp, endpos, &oplen, &args);
1831 gdb_assert (oplen > 0);
1833 pos = endpos - oplen;
1834 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1835 objfile_func, data))
1844 /* Helper for exp_uses_objfile. */
1847 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1849 struct objfile *objfile = (struct objfile *) objfile_voidp;
1851 if (exp_objfile->separate_debug_objfile_backlink)
1852 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1854 return exp_objfile == objfile;
1857 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1858 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1862 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1864 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1866 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1869 /* See definition in parser-defs.h. */
1872 increase_expout_size (struct parser_state *ps, size_t lenelt)
1874 if ((ps->expout_ptr + lenelt) >= ps->expout_size)
1876 ps->expout_size = std::max (ps->expout_size * 2,
1877 ps->expout_ptr + lenelt + 10);
1878 ps->expout.reset (XRESIZEVAR (expression,
1879 ps->expout.release (),
1880 (sizeof (struct expression)
1881 + EXP_ELEM_TO_BYTES (ps->expout_size))));
1886 _initialize_parse (void)
1888 type_stack.size = 0;
1889 type_stack.depth = 0;
1890 type_stack.elements = NULL;
1892 add_setshow_zuinteger_cmd ("expression", class_maintenance,
1894 _("Set expression debugging."),
1895 _("Show expression debugging."),
1896 _("When non-zero, the internal representation "
1897 "of expressions will be printed."),
1899 show_expressiondebug,
1900 &setdebuglist, &showdebuglist);
1901 add_setshow_boolean_cmd ("parser", class_maintenance,
1903 _("Set parser debugging."),
1904 _("Show parser debugging."),
1905 _("When non-zero, expression parser "
1906 "tracing will be enabled."),
1909 &setdebuglist, &showdebuglist);