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 innermost_block_tracker innermost_block;
70 static struct type_stack type_stack;
72 /* True if parsing an expression to attempt completion. */
75 /* The index of the last struct expression directly before a '.' or
76 '->'. This is set when parsing and is only used when completing a
77 field name. It is -1 if no dereference operation was found. */
78 static int expout_last_struct = -1;
80 /* If we are completing a tagged type name, this will be nonzero. */
81 static enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;
83 /* The token for tagged type name completion. */
84 static gdb::unique_xmalloc_ptr<char> expout_completion_name;
87 static unsigned int expressiondebug = 0;
89 show_expressiondebug (struct ui_file *file, int from_tty,
90 struct cmd_list_element *c, const char *value)
92 fprintf_filtered (file, _("Expression debugging is %s.\n"), value);
96 /* Non-zero if an expression parser should set yydebug. */
100 show_parserdebug (struct ui_file *file, int from_tty,
101 struct cmd_list_element *c, const char *value)
103 fprintf_filtered (file, _("Parser debugging is %s.\n"), value);
107 static int prefixify_subexp (struct expression *, struct expression *, int,
110 static expression_up parse_exp_in_context (const char **, CORE_ADDR,
111 const struct block *, int,
113 innermost_block_tracker_types);
115 static void increase_expout_size (struct expr_builder *ps, size_t lenelt);
118 /* Documented at it's declaration. */
121 innermost_block_tracker::update (const struct block *b,
122 innermost_block_tracker_types t)
124 if ((m_types & t) != 0
125 && (m_innermost_block == NULL
126 || contained_in (b, m_innermost_block)))
127 m_innermost_block = b;
132 /* See definition in parser-defs.h. */
134 expr_builder::expr_builder (const struct language_defn *lang,
135 struct gdbarch *gdbarch)
137 expout (XNEWVAR (expression,
139 + EXP_ELEM_TO_BYTES (expout_size)))),
142 expout->language_defn = lang;
143 expout->gdbarch = gdbarch;
147 expr_builder::release ()
149 /* Record the actual number of expression elements, and then
150 reallocate the expression memory so that we free up any
153 expout->nelts = expout_ptr;
154 expout.reset (XRESIZEVAR (expression, expout.release (),
156 + EXP_ELEM_TO_BYTES (expout_ptr))));
158 return std::move (expout);
161 /* This page contains the functions for adding data to the struct expression
162 being constructed. */
164 /* Add one element to the end of the expression. */
166 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
167 a register through here. */
170 write_exp_elt (struct expr_builder *ps, const union exp_element *expelt)
172 if (ps->expout_ptr >= ps->expout_size)
174 ps->expout_size *= 2;
175 ps->expout.reset (XRESIZEVAR (expression, ps->expout.release (),
177 + EXP_ELEM_TO_BYTES (ps->expout_size))));
179 ps->expout->elts[ps->expout_ptr++] = *expelt;
183 write_exp_elt_opcode (struct expr_builder *ps, enum exp_opcode expelt)
185 union exp_element tmp;
187 memset (&tmp, 0, sizeof (union exp_element));
189 write_exp_elt (ps, &tmp);
193 write_exp_elt_sym (struct expr_builder *ps, struct symbol *expelt)
195 union exp_element tmp;
197 memset (&tmp, 0, sizeof (union exp_element));
199 write_exp_elt (ps, &tmp);
203 write_exp_elt_msym (struct expr_builder *ps, minimal_symbol *expelt)
205 union exp_element tmp;
207 memset (&tmp, 0, sizeof (union exp_element));
208 tmp.msymbol = expelt;
209 write_exp_elt (ps, &tmp);
213 write_exp_elt_block (struct expr_builder *ps, const struct block *b)
215 union exp_element tmp;
217 memset (&tmp, 0, sizeof (union exp_element));
219 write_exp_elt (ps, &tmp);
223 write_exp_elt_objfile (struct expr_builder *ps, struct objfile *objfile)
225 union exp_element tmp;
227 memset (&tmp, 0, sizeof (union exp_element));
228 tmp.objfile = objfile;
229 write_exp_elt (ps, &tmp);
233 write_exp_elt_longcst (struct expr_builder *ps, LONGEST expelt)
235 union exp_element tmp;
237 memset (&tmp, 0, sizeof (union exp_element));
238 tmp.longconst = expelt;
239 write_exp_elt (ps, &tmp);
243 write_exp_elt_floatcst (struct expr_builder *ps, const gdb_byte expelt[16])
245 union exp_element tmp;
248 for (index = 0; index < 16; index++)
249 tmp.floatconst[index] = expelt[index];
251 write_exp_elt (ps, &tmp);
255 write_exp_elt_type (struct expr_builder *ps, struct type *expelt)
257 union exp_element tmp;
259 memset (&tmp, 0, sizeof (union exp_element));
261 write_exp_elt (ps, &tmp);
265 write_exp_elt_intern (struct expr_builder *ps, struct internalvar *expelt)
267 union exp_element tmp;
269 memset (&tmp, 0, sizeof (union exp_element));
270 tmp.internalvar = expelt;
271 write_exp_elt (ps, &tmp);
274 /* Add a string constant to the end of the expression.
276 String constants are stored by first writing an expression element
277 that contains the length of the string, then stuffing the string
278 constant itself into however many expression elements are needed
279 to hold it, and then writing another expression element that contains
280 the length of the string. I.e. an expression element at each end of
281 the string records the string length, so you can skip over the
282 expression elements containing the actual string bytes from either
283 end of the string. Note that this also allows gdb to handle
284 strings with embedded null bytes, as is required for some languages.
286 Don't be fooled by the fact that the string is null byte terminated,
287 this is strictly for the convenience of debugging gdb itself.
288 Gdb does not depend up the string being null terminated, since the
289 actual length is recorded in expression elements at each end of the
290 string. The null byte is taken into consideration when computing how
291 many expression elements are required to hold the string constant, of
296 write_exp_string (struct expr_builder *ps, struct stoken str)
298 int len = str.length;
302 /* Compute the number of expression elements required to hold the string
303 (including a null byte terminator), along with one expression element
304 at each end to record the actual string length (not including the
305 null byte terminator). */
307 lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);
309 increase_expout_size (ps, lenelt);
311 /* Write the leading length expression element (which advances the current
312 expression element index), then write the string constant followed by a
313 terminating null byte, and then write the trailing length expression
316 write_exp_elt_longcst (ps, (LONGEST) len);
317 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
318 memcpy (strdata, str.ptr, len);
319 *(strdata + len) = '\0';
320 ps->expout_ptr += lenelt - 2;
321 write_exp_elt_longcst (ps, (LONGEST) len);
324 /* Add a vector of string constants to the end of the expression.
326 This adds an OP_STRING operation, but encodes the contents
327 differently from write_exp_string. The language is expected to
328 handle evaluation of this expression itself.
330 After the usual OP_STRING header, TYPE is written into the
331 expression as a long constant. The interpretation of this field is
332 up to the language evaluator.
334 Next, each string in VEC is written. The length is written as a
335 long constant, followed by the contents of the string. */
338 write_exp_string_vector (struct expr_builder *ps, int type,
339 struct stoken_vector *vec)
344 /* Compute the size. We compute the size in number of slots to
345 avoid issues with string padding. */
347 for (i = 0; i < vec->len; ++i)
349 /* One slot for the length of this element, plus the number of
350 slots needed for this string. */
351 n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
354 /* One more slot for the type of the string. */
357 /* Now compute a phony string length. */
358 len = EXP_ELEM_TO_BYTES (n_slots) - 1;
361 increase_expout_size (ps, n_slots);
363 write_exp_elt_opcode (ps, OP_STRING);
364 write_exp_elt_longcst (ps, len);
365 write_exp_elt_longcst (ps, type);
367 for (i = 0; i < vec->len; ++i)
369 write_exp_elt_longcst (ps, vec->tokens[i].length);
370 memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr,
371 vec->tokens[i].length);
372 ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
375 write_exp_elt_longcst (ps, len);
376 write_exp_elt_opcode (ps, OP_STRING);
379 /* Add a bitstring constant to the end of the expression.
381 Bitstring constants are stored by first writing an expression element
382 that contains the length of the bitstring (in bits), then stuffing the
383 bitstring constant itself into however many expression elements are
384 needed to hold it, and then writing another expression element that
385 contains the length of the bitstring. I.e. an expression element at
386 each end of the bitstring records the bitstring length, so you can skip
387 over the expression elements containing the actual bitstring bytes from
388 either end of the bitstring. */
391 write_exp_bitstring (struct expr_builder *ps, struct stoken str)
393 int bits = str.length; /* length in bits */
394 int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
398 /* Compute the number of expression elements required to hold the bitstring,
399 along with one expression element at each end to record the actual
400 bitstring length in bits. */
402 lenelt = 2 + BYTES_TO_EXP_ELEM (len);
404 increase_expout_size (ps, lenelt);
406 /* Write the leading length expression element (which advances the current
407 expression element index), then write the bitstring constant, and then
408 write the trailing length expression element. */
410 write_exp_elt_longcst (ps, (LONGEST) bits);
411 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
412 memcpy (strdata, str.ptr, len);
413 ps->expout_ptr += lenelt - 2;
414 write_exp_elt_longcst (ps, (LONGEST) bits);
417 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
418 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
422 find_minsym_type_and_address (minimal_symbol *msymbol,
423 struct objfile *objfile,
424 CORE_ADDR *address_p)
426 bound_minimal_symbol bound_msym = {msymbol, objfile};
427 struct obj_section *section = MSYMBOL_OBJ_SECTION (objfile, msymbol);
428 enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
430 bool is_tls = (section != NULL
431 && section->the_bfd_section->flags & SEC_THREAD_LOCAL);
433 /* The minimal symbol might point to a function descriptor;
434 resolve it to the actual code address instead. */
438 /* Addresses of TLS symbols are really offsets into a
439 per-objfile/per-thread storage block. */
440 addr = MSYMBOL_VALUE_RAW_ADDRESS (bound_msym.minsym);
442 else if (msymbol_is_function (objfile, msymbol, &addr))
444 if (addr != BMSYMBOL_VALUE_ADDRESS (bound_msym))
446 /* This means we resolved a function descriptor, and we now
447 have an address for a code/text symbol instead of a data
449 if (MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc)
450 type = mst_text_gnu_ifunc;
457 addr = BMSYMBOL_VALUE_ADDRESS (bound_msym);
459 if (overlay_debugging)
460 addr = symbol_overlayed_address (addr, section);
464 /* Skip translation if caller does not need the address. */
465 if (address_p != NULL)
466 *address_p = target_translate_tls_address (objfile, addr);
467 return objfile_type (objfile)->nodebug_tls_symbol;
470 if (address_p != NULL)
477 case mst_solib_trampoline:
478 return objfile_type (objfile)->nodebug_text_symbol;
480 case mst_text_gnu_ifunc:
481 return objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
487 return objfile_type (objfile)->nodebug_data_symbol;
489 case mst_slot_got_plt:
490 return objfile_type (objfile)->nodebug_got_plt_symbol;
493 return objfile_type (objfile)->nodebug_unknown_symbol;
497 /* Add the appropriate elements for a minimal symbol to the end of
501 write_exp_msymbol (struct expr_builder *ps,
502 struct bound_minimal_symbol bound_msym)
504 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
505 write_exp_elt_objfile (ps, bound_msym.objfile);
506 write_exp_elt_msym (ps, bound_msym.minsym);
507 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
510 /* Mark the current index as the starting location of a structure
511 expression. This is used when completing on field names. */
514 mark_struct_expression (struct expr_builder *ps)
516 gdb_assert (parse_completion
517 && expout_tag_completion_type == TYPE_CODE_UNDEF);
518 expout_last_struct = ps->expout_ptr;
521 /* Indicate that the current parser invocation is completing a tag.
522 TAG is the type code of the tag, and PTR and LENGTH represent the
523 start of the tag name. */
526 mark_completion_tag (enum type_code tag, const char *ptr, int length)
528 gdb_assert (parse_completion
529 && expout_tag_completion_type == TYPE_CODE_UNDEF
530 && expout_completion_name == NULL
531 && expout_last_struct == -1);
532 gdb_assert (tag == TYPE_CODE_UNION
533 || tag == TYPE_CODE_STRUCT
534 || tag == TYPE_CODE_ENUM);
535 expout_tag_completion_type = tag;
536 expout_completion_name.reset (xstrndup (ptr, length));
540 /* Recognize tokens that start with '$'. These include:
542 $regname A native register name or a "standard
545 $variable A convenience variable with a name chosen
548 $digits Value history with index <digits>, starting
549 from the first value which has index 1.
551 $$digits Value history with index <digits> relative
552 to the last value. I.e. $$0 is the last
553 value, $$1 is the one previous to that, $$2
554 is the one previous to $$1, etc.
556 $ | $0 | $$0 The last value in the value history.
558 $$ An abbreviation for the second to the last
559 value in the value history, I.e. $$1 */
562 write_dollar_variable (struct parser_state *ps, struct stoken str)
564 struct block_symbol sym;
565 struct bound_minimal_symbol msym;
566 struct internalvar *isym = NULL;
568 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
569 and $$digits (equivalent to $<-digits> if you could type that). */
573 /* Double dollar means negate the number and add -1 as well.
574 Thus $$ alone means -1. */
575 if (str.length >= 2 && str.ptr[1] == '$')
582 /* Just dollars (one or two). */
586 /* Is the rest of the token digits? */
587 for (; i < str.length; i++)
588 if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
592 i = atoi (str.ptr + 1 + negate);
598 /* Handle tokens that refer to machine registers:
599 $ followed by a register name. */
600 i = user_reg_map_name_to_regnum (ps->gdbarch (),
601 str.ptr + 1, str.length - 1);
603 goto handle_register;
605 /* Any names starting with $ are probably debugger internal variables. */
607 isym = lookup_only_internalvar (copy_name (str) + 1);
610 write_exp_elt_opcode (ps, OP_INTERNALVAR);
611 write_exp_elt_intern (ps, isym);
612 write_exp_elt_opcode (ps, OP_INTERNALVAR);
616 /* On some systems, such as HP-UX and hppa-linux, certain system routines
617 have names beginning with $ or $$. Check for those, first. */
619 sym = lookup_symbol (copy_name (str), NULL, VAR_DOMAIN, NULL);
622 write_exp_elt_opcode (ps, OP_VAR_VALUE);
623 write_exp_elt_block (ps, sym.block);
624 write_exp_elt_sym (ps, sym.symbol);
625 write_exp_elt_opcode (ps, OP_VAR_VALUE);
628 msym = lookup_bound_minimal_symbol (copy_name (str));
631 write_exp_msymbol (ps, msym);
635 /* Any other names are assumed to be debugger internal variables. */
637 write_exp_elt_opcode (ps, OP_INTERNALVAR);
638 write_exp_elt_intern (ps, create_internalvar (copy_name (str) + 1));
639 write_exp_elt_opcode (ps, OP_INTERNALVAR);
642 write_exp_elt_opcode (ps, OP_LAST);
643 write_exp_elt_longcst (ps, (LONGEST) i);
644 write_exp_elt_opcode (ps, OP_LAST);
647 write_exp_elt_opcode (ps, OP_REGISTER);
650 write_exp_string (ps, str);
651 write_exp_elt_opcode (ps, OP_REGISTER);
652 innermost_block.update (ps->expression_context_block,
653 INNERMOST_BLOCK_FOR_REGISTERS);
659 find_template_name_end (const char *p)
662 int just_seen_right = 0;
663 int just_seen_colon = 0;
664 int just_seen_space = 0;
666 if (!p || (*p != '<'))
677 /* In future, may want to allow these?? */
680 depth++; /* start nested template */
681 if (just_seen_colon || just_seen_right || just_seen_space)
682 return 0; /* but not after : or :: or > or space */
685 if (just_seen_colon || just_seen_right)
686 return 0; /* end a (nested?) template */
687 just_seen_right = 1; /* but not after : or :: */
688 if (--depth == 0) /* also disallow >>, insist on > > */
689 return ++p; /* if outermost ended, return */
692 if (just_seen_space || (just_seen_colon > 1))
693 return 0; /* nested class spec coming up */
694 just_seen_colon++; /* we allow :: but not :::: */
699 if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
700 (*p >= 'A' && *p <= 'Z') ||
701 (*p >= '0' && *p <= '9') ||
702 (*p == '_') || (*p == ',') || /* commas for template args */
703 (*p == '&') || (*p == '*') || /* pointer and ref types */
704 (*p == '(') || (*p == ')') || /* function types */
705 (*p == '[') || (*p == ']'))) /* array types */
719 /* Return a null-terminated temporary copy of the name of a string token.
721 Tokens that refer to names do so with explicit pointer and length,
722 so they can share the storage that lexptr is parsing.
723 When it is necessary to pass a name to a function that expects
724 a null-terminated string, the substring is copied out
725 into a separate block of storage.
727 N.B. A single buffer is reused on each call. */
730 copy_name (struct stoken token)
732 /* A temporary buffer for identifiers, so we can null-terminate them.
733 We allocate this with xrealloc. parse_exp_1 used to allocate with
734 alloca, using the size of the whole expression as a conservative
735 estimate of the space needed. However, macro expansion can
736 introduce names longer than the original expression; there's no
737 practical way to know beforehand how large that might be. */
738 static char *namecopy;
739 static size_t namecopy_size;
741 /* Make sure there's enough space for the token. */
742 if (namecopy_size < token.length + 1)
744 namecopy_size = token.length + 1;
745 namecopy = (char *) xrealloc (namecopy, token.length + 1);
748 memcpy (namecopy, token.ptr, token.length);
749 namecopy[token.length] = 0;
755 /* See comments on parser-defs.h. */
758 prefixify_expression (struct expression *expr)
760 gdb_assert (expr->nelts > 0);
761 int len = sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts);
762 struct expression *temp;
763 int inpos = expr->nelts, outpos = 0;
765 temp = (struct expression *) alloca (len);
767 /* Copy the original expression into temp. */
768 memcpy (temp, expr, len);
770 return prefixify_subexp (temp, expr, inpos, outpos);
773 /* Return the number of exp_elements in the postfix subexpression
774 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
777 length_of_subexp (struct expression *expr, int endpos)
781 operator_length (expr, endpos, &oplen, &args);
785 oplen += length_of_subexp (expr, endpos - oplen);
792 /* Sets *OPLENP to the length of the operator whose (last) index is
793 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
797 operator_length (const struct expression *expr, int endpos, int *oplenp,
800 expr->language_defn->la_exp_desc->operator_length (expr, endpos,
804 /* Default value for operator_length in exp_descriptor vectors. */
807 operator_length_standard (const struct expression *expr, int endpos,
808 int *oplenp, int *argsp)
812 enum range_type range_type;
816 error (_("?error in operator_length_standard"));
818 i = (int) expr->elts[endpos - 1].opcode;
824 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
825 oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
831 case OP_VAR_MSYM_VALUE:
835 case OP_FUNC_STATIC_VAR:
836 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
837 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
845 case OP_VAR_ENTRY_VALUE:
855 case OP_F77_UNDETERMINED_ARGLIST:
857 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
861 oplen = 5 + longest_to_int (expr->elts[endpos - 2].longconst);
865 case OP_OBJC_MSGCALL: /* Objective C message (method) call. */
867 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
876 case UNOP_DYNAMIC_CAST:
877 case UNOP_REINTERPRET_CAST:
878 case UNOP_MEMVAL_TYPE:
907 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
908 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
913 case STRUCTOP_STRUCT:
920 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
921 NSString constant. */
922 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
924 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
925 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
930 args = longest_to_int (expr->elts[endpos - 2].longconst);
931 args -= longest_to_int (expr->elts[endpos - 3].longconst);
941 case MULTI_SUBSCRIPT:
943 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
946 case BINOP_ASSIGN_MODIFY:
958 range_type = (enum range_type)
959 longest_to_int (expr->elts[endpos - 2].longconst);
963 case LOW_BOUND_DEFAULT:
964 case LOW_BOUND_DEFAULT_EXCLUSIVE:
965 case HIGH_BOUND_DEFAULT:
968 case BOTH_BOUND_DEFAULT:
971 case NONE_BOUND_DEFAULT:
972 case NONE_BOUND_DEFAULT_EXCLUSIVE:
980 args = 1 + (i < (int) BINOP_END);
987 /* Copy the subexpression ending just before index INEND in INEXPR
988 into OUTEXPR, starting at index OUTBEG.
989 In the process, convert it from suffix to prefix form.
990 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
991 Otherwise, it returns the index of the subexpression which is the
992 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
995 prefixify_subexp (struct expression *inexpr,
996 struct expression *outexpr, int inend, int outbeg)
1004 operator_length (inexpr, inend, &oplen, &args);
1006 /* Copy the final operator itself, from the end of the input
1007 to the beginning of the output. */
1009 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1010 EXP_ELEM_TO_BYTES (oplen));
1013 if (expout_last_struct == inend)
1014 result = outbeg - oplen;
1016 /* Find the lengths of the arg subexpressions. */
1017 arglens = (int *) alloca (args * sizeof (int));
1018 for (i = args - 1; i >= 0; i--)
1020 oplen = length_of_subexp (inexpr, inend);
1025 /* Now copy each subexpression, preserving the order of
1026 the subexpressions, but prefixifying each one.
1027 In this loop, inend starts at the beginning of
1028 the expression this level is working on
1029 and marches forward over the arguments.
1030 outbeg does similarly in the output. */
1031 for (i = 0; i < args; i++)
1037 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1040 /* Return immediately. We probably have only parsed a
1041 partial expression, so we don't want to try to reverse
1042 the other operands. */
1051 /* Read an expression from the string *STRINGPTR points to,
1052 parse it, and return a pointer to a struct expression that we malloc.
1053 Use block BLOCK as the lexical context for variable names;
1054 if BLOCK is zero, use the block of the selected stack frame.
1055 Meanwhile, advance *STRINGPTR to point after the expression,
1056 at the first nonwhite character that is not part of the expression
1057 (possibly a null character).
1059 If COMMA is nonzero, stop if a comma is reached. */
1062 parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
1063 int comma, innermost_block_tracker_types tracker_types)
1065 return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL,
1069 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1070 no value is expected from the expression.
1071 OUT_SUBEXP is set when attempting to complete a field name; in this
1072 case it is set to the index of the subexpression on the
1073 left-hand-side of the struct op. If not doing such completion, it
1074 is left untouched. */
1076 static expression_up
1077 parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
1078 const struct block *block,
1079 int comma, int void_context_p, int *out_subexp,
1080 innermost_block_tracker_types tracker_types)
1082 const struct language_defn *lang = NULL;
1085 type_stack.elements.clear ();
1086 expout_last_struct = -1;
1087 expout_tag_completion_type = TYPE_CODE_UNDEF;
1088 expout_completion_name.reset ();
1089 innermost_block.reset (tracker_types);
1091 if (*stringptr == 0 || **stringptr == 0)
1092 error_no_arg (_("expression to compute"));
1094 const struct block *expression_context_block = block;
1095 CORE_ADDR expression_context_pc = 0;
1097 /* If no context specified, try using the current frame, if any. */
1098 if (!expression_context_block)
1099 expression_context_block = get_selected_block (&expression_context_pc);
1101 expression_context_pc = BLOCK_ENTRY_PC (expression_context_block);
1103 expression_context_pc = pc;
1105 /* Fall back to using the current source static context, if any. */
1107 if (!expression_context_block)
1109 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1111 expression_context_block
1112 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
1114 if (expression_context_block)
1115 expression_context_pc = BLOCK_ENTRY_PC (expression_context_block);
1118 if (language_mode == language_mode_auto && block != NULL)
1120 /* Find the language associated to the given context block.
1121 Default to the current language if it can not be determined.
1123 Note that using the language corresponding to the current frame
1124 can sometimes give unexpected results. For instance, this
1125 routine is often called several times during the inferior
1126 startup phase to re-parse breakpoint expressions after
1127 a new shared library has been loaded. The language associated
1128 to the current frame at this moment is not relevant for
1129 the breakpoint. Using it would therefore be silly, so it seems
1130 better to rely on the current language rather than relying on
1131 the current frame language to parse the expression. That's why
1132 we do the following language detection only if the context block
1133 has been specifically provided. */
1134 struct symbol *func = block_linkage_function (block);
1137 lang = language_def (SYMBOL_LANGUAGE (func));
1138 if (lang == NULL || lang->la_language == language_unknown)
1139 lang = current_language;
1142 lang = current_language;
1144 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1145 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1146 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1147 to the value matching SELECTED_FRAME as set by get_current_arch. */
1149 parser_state ps (lang, get_current_arch (), expression_context_block,
1150 expression_context_pc, comma, *stringptr);
1152 scoped_restore_current_language lang_saver;
1153 set_language (lang->la_language);
1157 lang->la_parser (&ps);
1159 CATCH (except, RETURN_MASK_ALL)
1161 /* If parsing for completion, allow this to succeed; but if no
1162 expression elements have been written, then there's nothing
1164 if (! parse_completion || ps.expout_ptr == 0)
1165 throw_exception (except);
1169 /* We have to operate on an "expression *", due to la_post_parser,
1170 which explains this funny-looking double release. */
1171 expression_up result = ps.release ();
1173 /* Convert expression from postfix form as generated by yacc
1174 parser, to a prefix form. */
1176 if (expressiondebug)
1177 dump_raw_expression (result.get (), gdb_stdlog,
1178 "before conversion to prefix form");
1180 subexp = prefixify_expression (result.get ());
1182 *out_subexp = subexp;
1184 lang->la_post_parser (&result, void_context_p);
1186 if (expressiondebug)
1187 dump_prefix_expression (result.get (), gdb_stdlog);
1189 *stringptr = ps.lexptr;
1193 /* Parse STRING as an expression, and complain if this fails
1194 to use up all of the contents of STRING. */
1197 parse_expression (const char *string)
1199 expression_up exp = parse_exp_1 (&string, 0, 0, 0);
1201 error (_("Junk after end of expression."));
1205 /* Same as parse_expression, but using the given language (LANG)
1206 to parse the expression. */
1209 parse_expression_with_language (const char *string, enum language lang)
1211 gdb::optional<scoped_restore_current_language> lang_saver;
1212 if (current_language->la_language != lang)
1214 lang_saver.emplace ();
1215 set_language (lang);
1218 return parse_expression (string);
1221 /* Parse STRING as an expression. If parsing ends in the middle of a
1222 field reference, return the type of the left-hand-side of the
1223 reference; furthermore, if the parsing ends in the field name,
1224 return the field name in *NAME. If the parsing ends in the middle
1225 of a field reference, but the reference is somehow invalid, throw
1226 an exception. In all other cases, return NULL. */
1229 parse_expression_for_completion (const char *string,
1230 gdb::unique_xmalloc_ptr<char> *name,
1231 enum type_code *code)
1239 parse_completion = 1;
1240 exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp,
1241 INNERMOST_BLOCK_FOR_SYMBOLS);
1243 CATCH (except, RETURN_MASK_ERROR)
1245 /* Nothing, EXP remains NULL. */
1249 parse_completion = 0;
1253 if (expout_tag_completion_type != TYPE_CODE_UNDEF)
1255 *code = expout_tag_completion_type;
1256 *name = std::move (expout_completion_name);
1260 if (expout_last_struct == -1)
1263 const char *fieldname = extract_field_op (exp.get (), &subexp);
1264 if (fieldname == NULL)
1270 name->reset (xstrdup (fieldname));
1271 /* This might throw an exception. If so, we want to let it
1273 val = evaluate_subexpression_type (exp.get (), subexp);
1275 return value_type (val);
1278 /* A post-parser that does nothing. */
1281 null_post_parser (expression_up *exp, int void_context_p)
1285 /* Parse floating point value P of length LEN.
1286 Return false if invalid, true if valid.
1287 The successfully parsed number is stored in DATA in
1288 target format for floating-point type TYPE.
1290 NOTE: This accepts the floating point syntax that sscanf accepts. */
1293 parse_float (const char *p, int len,
1294 const struct type *type, gdb_byte *data)
1296 return target_float_from_string (data, type, std::string (p, len));
1299 /* Stuff for maintaining a stack of types. Currently just used by C, but
1300 probably useful for any language which declares its types "backwards". */
1302 /* A helper function for insert_type and insert_type_address_space.
1303 This does work of expanding the type stack and inserting the new
1304 element, ELEMENT, into the stack at location SLOT. */
1307 insert_into_type_stack (int slot, union type_stack_elt element)
1309 gdb_assert (slot <= type_stack.elements.size ());
1310 type_stack.elements.insert (type_stack.elements.begin () + slot, element);
1313 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1314 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1315 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1316 previous tp_pointer) if there is anything on the stack, or simply pushed
1317 if the stack is empty. Other values for TP are invalid. */
1320 insert_type (enum type_pieces tp)
1322 union type_stack_elt element;
1325 gdb_assert (tp == tp_pointer || tp == tp_reference
1326 || tp == tp_rvalue_reference || tp == tp_const
1327 || tp == tp_volatile);
1329 /* If there is anything on the stack (we know it will be a
1330 tp_pointer), insert the qualifier above it. Otherwise, simply
1331 push this on the top of the stack. */
1332 if (!type_stack.elements.empty () && (tp == tp_const || tp == tp_volatile))
1338 insert_into_type_stack (slot, element);
1342 push_type (enum type_pieces tp)
1346 type_stack.elements.push_back (elt);
1350 push_type_int (int n)
1354 type_stack.elements.push_back (elt);
1357 /* Insert a tp_space_identifier and the corresponding address space
1358 value into the stack. STRING is the name of an address space, as
1359 recognized by address_space_name_to_int. If the stack is empty,
1360 the new elements are simply pushed. If the stack is not empty,
1361 this function assumes that the first item on the stack is a
1362 tp_pointer, and the new values are inserted above the first
1366 insert_type_address_space (struct expr_builder *pstate, char *string)
1368 union type_stack_elt element;
1371 /* If there is anything on the stack (we know it will be a
1372 tp_pointer), insert the address space qualifier above it.
1373 Otherwise, simply push this on the top of the stack. */
1374 if (!type_stack.elements.empty ())
1379 element.piece = tp_space_identifier;
1380 insert_into_type_stack (slot, element);
1381 element.int_val = address_space_name_to_int (pstate->gdbarch (),
1383 insert_into_type_stack (slot, element);
1389 if (!type_stack.elements.empty ())
1391 type_stack_elt elt = type_stack.elements.back ();
1392 type_stack.elements.pop_back ();
1401 if (!type_stack.elements.empty ())
1403 type_stack_elt elt = type_stack.elements.back ();
1404 type_stack.elements.pop_back ();
1407 /* "Can't happen". */
1411 /* Pop a type list element from the global type stack. */
1413 static std::vector<struct type *> *
1416 gdb_assert (!type_stack.elements.empty ());
1417 type_stack_elt elt = type_stack.elements.back ();
1418 type_stack.elements.pop_back ();
1419 return elt.typelist_val;
1422 /* Pop a type_stack element from the global type stack. */
1424 static struct type_stack *
1425 pop_type_stack (void)
1427 gdb_assert (!type_stack.elements.empty ());
1428 type_stack_elt elt = type_stack.elements.back ();
1429 type_stack.elements.pop_back ();
1430 return elt.stack_val;
1433 /* Append the elements of the type stack FROM to the type stack TO.
1434 Always returns TO. */
1437 append_type_stack (struct type_stack *to, struct type_stack *from)
1439 to->elements.insert (to->elements.end (), from->elements.begin (),
1440 from->elements.end ());
1444 /* Push the type stack STACK as an element on the global type stack. */
1447 push_type_stack (struct type_stack *stack)
1450 elt.stack_val = stack;
1451 type_stack.elements.push_back (elt);
1452 push_type (tp_type_stack);
1455 /* Copy the global type stack into a newly allocated type stack and
1456 return it. The global stack is cleared. The returned type stack
1457 must be freed with delete. */
1460 get_type_stack (void)
1462 struct type_stack *result = new struct type_stack (std::move (type_stack));
1463 type_stack.elements.clear ();
1467 /* Push a function type with arguments onto the global type stack.
1468 LIST holds the argument types. If the final item in LIST is NULL,
1469 then the function will be varargs. */
1472 push_typelist (std::vector<struct type *> *list)
1475 elt.typelist_val = list;
1476 type_stack.elements.push_back (elt);
1477 push_type (tp_function_with_arguments);
1480 /* Pop the type stack and return a type_instance_flags that
1481 corresponds the const/volatile qualifiers on the stack. This is
1482 called by the C++ parser when parsing methods types, and as such no
1483 other kind of type in the type stack is expected. */
1486 follow_type_instance_flags ()
1488 type_instance_flags flags = 0;
1491 switch (pop_type ())
1496 flags |= TYPE_INSTANCE_FLAG_CONST;
1499 flags |= TYPE_INSTANCE_FLAG_VOLATILE;
1502 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1507 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1508 as modified by all the stuff on the stack. */
1510 follow_types (struct type *follow_type)
1514 int make_volatile = 0;
1515 int make_addr_space = 0;
1519 switch (pop_type ())
1524 follow_type = make_cv_type (make_const,
1525 TYPE_VOLATILE (follow_type),
1528 follow_type = make_cv_type (TYPE_CONST (follow_type),
1531 if (make_addr_space)
1532 follow_type = make_type_with_address_space (follow_type,
1534 make_const = make_volatile = 0;
1535 make_addr_space = 0;
1543 case tp_space_identifier:
1544 make_addr_space = pop_type_int ();
1547 follow_type = lookup_pointer_type (follow_type);
1549 follow_type = make_cv_type (make_const,
1550 TYPE_VOLATILE (follow_type),
1553 follow_type = make_cv_type (TYPE_CONST (follow_type),
1556 if (make_addr_space)
1557 follow_type = make_type_with_address_space (follow_type,
1559 make_const = make_volatile = 0;
1560 make_addr_space = 0;
1563 follow_type = lookup_lvalue_reference_type (follow_type);
1564 goto process_reference;
1565 case tp_rvalue_reference:
1566 follow_type = lookup_rvalue_reference_type (follow_type);
1569 follow_type = make_cv_type (make_const,
1570 TYPE_VOLATILE (follow_type),
1573 follow_type = make_cv_type (TYPE_CONST (follow_type),
1576 if (make_addr_space)
1577 follow_type = make_type_with_address_space (follow_type,
1579 make_const = make_volatile = 0;
1580 make_addr_space = 0;
1583 array_size = pop_type_int ();
1584 /* FIXME-type-allocation: need a way to free this type when we are
1587 lookup_array_range_type (follow_type,
1588 0, array_size >= 0 ? array_size - 1 : 0);
1590 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type))
1594 /* FIXME-type-allocation: need a way to free this type when we are
1596 follow_type = lookup_function_type (follow_type);
1599 case tp_function_with_arguments:
1601 std::vector<struct type *> *args = pop_typelist ();
1604 = lookup_function_type_with_arguments (follow_type,
1612 struct type_stack *stack = pop_type_stack ();
1613 /* Sort of ugly, but not really much worse than the
1615 struct type_stack save = type_stack;
1617 type_stack = *stack;
1618 follow_type = follow_types (follow_type);
1619 gdb_assert (type_stack.elements.empty ());
1625 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1630 /* This function avoids direct calls to fprintf
1631 in the parser generated debug code. */
1633 parser_fprintf (FILE *x, const char *y, ...)
1639 vfprintf_unfiltered (gdb_stderr, y, args);
1642 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1643 vfprintf_unfiltered (gdb_stderr, y, args);
1648 /* Implementation of the exp_descriptor method operator_check. */
1651 operator_check_standard (struct expression *exp, int pos,
1652 int (*objfile_func) (struct objfile *objfile,
1656 const union exp_element *const elts = exp->elts;
1657 struct type *type = NULL;
1658 struct objfile *objfile = NULL;
1660 /* Extended operators should have been already handled by exp_descriptor
1661 iterate method of its specific language. */
1662 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1664 /* Track the callers of write_exp_elt_type for this table. */
1666 switch (elts[pos].opcode)
1678 type = elts[pos + 1].type;
1683 LONGEST arg, nargs = elts[pos + 2].longconst;
1685 for (arg = 0; arg < nargs; arg++)
1687 struct type *inst_type = elts[pos + 3 + arg].type;
1688 struct objfile *inst_objfile = TYPE_OBJFILE (inst_type);
1690 if (inst_objfile && (*objfile_func) (inst_objfile, data))
1698 const struct block *const block = elts[pos + 1].block;
1699 const struct symbol *const symbol = elts[pos + 2].symbol;
1701 /* Check objfile where the variable itself is placed.
1702 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1703 if ((*objfile_func) (symbol_objfile (symbol), data))
1706 /* Check objfile where is placed the code touching the variable. */
1707 objfile = lookup_objfile_from_block (block);
1709 type = SYMBOL_TYPE (symbol);
1712 case OP_VAR_MSYM_VALUE:
1713 objfile = elts[pos + 1].objfile;
1717 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1719 if (type && TYPE_OBJFILE (type)
1720 && (*objfile_func) (TYPE_OBJFILE (type), data))
1722 if (objfile && (*objfile_func) (objfile, data))
1728 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1729 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1730 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1731 returns non-zero value then (any other) non-zero value is immediately
1732 returned to the caller. Otherwise zero is returned after iterating
1733 through whole EXP. */
1736 exp_iterate (struct expression *exp,
1737 int (*objfile_func) (struct objfile *objfile, void *data),
1742 for (endpos = exp->nelts; endpos > 0; )
1744 int pos, args, oplen = 0;
1746 operator_length (exp, endpos, &oplen, &args);
1747 gdb_assert (oplen > 0);
1749 pos = endpos - oplen;
1750 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1751 objfile_func, data))
1760 /* Helper for exp_uses_objfile. */
1763 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1765 struct objfile *objfile = (struct objfile *) objfile_voidp;
1767 if (exp_objfile->separate_debug_objfile_backlink)
1768 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1770 return exp_objfile == objfile;
1773 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1774 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1778 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1780 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1782 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1785 /* Reallocate the `expout' pointer inside PS so that it can accommodate
1786 at least LENELT expression elements. This function does nothing if
1787 there is enough room for the elements. */
1790 increase_expout_size (struct expr_builder *ps, size_t lenelt)
1792 if ((ps->expout_ptr + lenelt) >= ps->expout_size)
1794 ps->expout_size = std::max (ps->expout_size * 2,
1795 ps->expout_ptr + lenelt + 10);
1796 ps->expout.reset (XRESIZEVAR (expression,
1797 ps->expout.release (),
1798 (sizeof (struct expression)
1799 + EXP_ELEM_TO_BYTES (ps->expout_size))));
1804 _initialize_parse (void)
1806 add_setshow_zuinteger_cmd ("expression", class_maintenance,
1808 _("Set expression debugging."),
1809 _("Show expression debugging."),
1810 _("When non-zero, the internal representation "
1811 "of expressions will be printed."),
1813 show_expressiondebug,
1814 &setdebuglist, &showdebuglist);
1815 add_setshow_boolean_cmd ("parser", class_maintenance,
1817 _("Set parser debugging."),
1818 _("Show parser debugging."),
1819 _("When non-zero, expression parser "
1820 "tracing will be enabled."),
1823 &setdebuglist, &showdebuglist);