1 /* Parse expressions for GDB.
3 Copyright (C) 1986, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
4 1998, 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2009, 2010, 2011
5 Free Software Foundation, Inc.
7 Modified from expread.y by the Department of Computer Science at the
8 State University of New York at Buffalo, 1991.
10 This file is part of GDB.
12 This program is free software; you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation; either version 3 of the License, or
15 (at your option) any later version.
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
22 You should have received a copy of the GNU General Public License
23 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 /* Parse an expression from text in a string,
26 and return the result as a struct expression pointer.
27 That structure contains arithmetic operations in reverse polish,
28 with constants represented by operations that are followed by special data.
29 See expression.h for the details of the format.
30 What is important here is that it can be built up sequentially
31 during the process of parsing; the lower levels of the tree always
32 come first in the result. */
36 #include "arch-utils.h"
37 #include "gdb_string.h"
41 #include "expression.h"
46 #include "parser-defs.h"
48 #include "symfile.h" /* for overlay functions */
51 #include "gdb_assert.h"
55 #include "exceptions.h"
56 #include "user-regs.h"
58 /* Standard set of definitions for printing, dumping, prefixifying,
59 * and evaluating expressions. */
61 const struct exp_descriptor exp_descriptor_standard =
63 print_subexp_standard,
64 operator_length_standard,
65 operator_check_standard,
67 dump_subexp_body_standard,
68 evaluate_subexp_standard
71 /* Global variables declared in parser-defs.h (and commented there). */
72 struct expression *expout;
75 struct block *expression_context_block;
76 CORE_ADDR expression_context_pc;
77 struct block *innermost_block;
79 union type_stack_elt *type_stack;
80 int type_stack_depth, type_stack_size;
86 /* True if parsing an expression to find a field reference. This is
87 only used by completion. */
90 /* The index of the last struct expression directly before a '.' or
91 '->'. This is set when parsing and is only used when completing a
92 field name. It is -1 if no dereference operation was found. */
93 static int expout_last_struct = -1;
95 /* A temporary buffer for identifiers, so we can null-terminate them.
97 We allocate this with xrealloc. parse_exp_1 used to allocate with
98 alloca, using the size of the whole expression as a conservative
99 estimate of the space needed. However, macro expansion can
100 introduce names longer than the original expression; there's no
101 practical way to know beforehand how large that might be. */
103 size_t namecopy_size;
105 static int expressiondebug = 0;
107 show_expressiondebug (struct ui_file *file, int from_tty,
108 struct cmd_list_element *c, const char *value)
110 fprintf_filtered (file, _("Expression debugging is %s.\n"), value);
114 /* Non-zero if an expression parser should set yydebug. */
118 show_parserdebug (struct ui_file *file, int from_tty,
119 struct cmd_list_element *c, const char *value)
121 fprintf_filtered (file, _("Parser debugging is %s.\n"), value);
125 static void free_funcalls (void *ignore);
127 static int prefixify_expression (struct expression *);
129 static int prefixify_subexp (struct expression *, struct expression *, int,
132 static struct expression *parse_exp_in_context (char **, struct block *, int,
135 void _initialize_parse (void);
137 /* Data structure for saving values of arglist_len for function calls whose
138 arguments contain other function calls. */
142 struct funcall *next;
146 static struct funcall *funcall_chain;
148 /* Begin counting arguments for a function call,
149 saving the data about any containing call. */
156 new = (struct funcall *) xmalloc (sizeof (struct funcall));
157 new->next = funcall_chain;
158 new->arglist_len = arglist_len;
163 /* Return the number of arguments in a function call just terminated,
164 and restore the data for the containing function call. */
169 int val = arglist_len;
170 struct funcall *call = funcall_chain;
172 funcall_chain = call->next;
173 arglist_len = call->arglist_len;
178 /* Free everything in the funcall chain.
179 Used when there is an error inside parsing. */
182 free_funcalls (void *ignore)
184 struct funcall *call, *next;
186 for (call = funcall_chain; call; call = next)
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 (union exp_element expelt)
204 if (expout_ptr >= expout_size)
207 expout = (struct expression *)
208 xrealloc ((char *) expout, sizeof (struct expression)
209 + EXP_ELEM_TO_BYTES (expout_size));
211 expout->elts[expout_ptr++] = expelt;
215 write_exp_elt_opcode (enum exp_opcode expelt)
217 union exp_element tmp;
219 memset (&tmp, 0, sizeof (union exp_element));
225 write_exp_elt_sym (struct symbol *expelt)
227 union exp_element tmp;
229 memset (&tmp, 0, sizeof (union exp_element));
235 write_exp_elt_block (struct block *b)
237 union exp_element tmp;
239 memset (&tmp, 0, sizeof (union exp_element));
245 write_exp_elt_objfile (struct objfile *objfile)
247 union exp_element tmp;
249 memset (&tmp, 0, sizeof (union exp_element));
250 tmp.objfile = objfile;
255 write_exp_elt_longcst (LONGEST expelt)
257 union exp_element tmp;
259 memset (&tmp, 0, sizeof (union exp_element));
260 tmp.longconst = expelt;
265 write_exp_elt_dblcst (DOUBLEST expelt)
267 union exp_element tmp;
269 memset (&tmp, 0, sizeof (union exp_element));
270 tmp.doubleconst = expelt;
275 write_exp_elt_decfloatcst (gdb_byte expelt[16])
277 union exp_element tmp;
280 for (index = 0; index < 16; index++)
281 tmp.decfloatconst[index] = expelt[index];
287 write_exp_elt_type (struct type *expelt)
289 union exp_element tmp;
291 memset (&tmp, 0, sizeof (union exp_element));
297 write_exp_elt_intern (struct internalvar *expelt)
299 union exp_element tmp;
301 memset (&tmp, 0, sizeof (union exp_element));
302 tmp.internalvar = expelt;
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 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 /* Ensure that we have enough available expression elements to store
344 if ((expout_ptr + lenelt) >= expout_size)
346 expout_size = max (expout_size * 2, expout_ptr + lenelt + 10);
347 expout = (struct expression *)
348 xrealloc ((char *) expout, (sizeof (struct expression)
349 + EXP_ELEM_TO_BYTES (expout_size)));
352 /* Write the leading length expression element (which advances the current
353 expression element index), then write the string constant followed by a
354 terminating null byte, and then write the trailing length expression
357 write_exp_elt_longcst ((LONGEST) len);
358 strdata = (char *) &expout->elts[expout_ptr];
359 memcpy (strdata, str.ptr, len);
360 *(strdata + len) = '\0';
361 expout_ptr += lenelt - 2;
362 write_exp_elt_longcst ((LONGEST) len);
365 /* Add a vector of string constants to the end of the expression.
367 This adds an OP_STRING operation, but encodes the contents
368 differently from write_exp_string. The language is expected to
369 handle evaluation of this expression itself.
371 After the usual OP_STRING header, TYPE is written into the
372 expression as a long constant. The interpretation of this field is
373 up to the language evaluator.
375 Next, each string in VEC is written. The length is written as a
376 long constant, followed by the contents of the string. */
379 write_exp_string_vector (int type, struct stoken_vector *vec)
383 /* Compute the size. We compute the size in number of slots to
384 avoid issues with string padding. */
386 for (i = 0; i < vec->len; ++i)
388 /* One slot for the length of this element, plus the number of
389 slots needed for this string. */
390 n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
393 /* One more slot for the type of the string. */
396 /* Now compute a phony string length. */
397 len = EXP_ELEM_TO_BYTES (n_slots) - 1;
400 if ((expout_ptr + n_slots) >= expout_size)
402 expout_size = max (expout_size * 2, expout_ptr + n_slots + 10);
403 expout = (struct expression *)
404 xrealloc ((char *) expout, (sizeof (struct expression)
405 + EXP_ELEM_TO_BYTES (expout_size)));
408 write_exp_elt_opcode (OP_STRING);
409 write_exp_elt_longcst (len);
410 write_exp_elt_longcst (type);
412 for (i = 0; i < vec->len; ++i)
414 write_exp_elt_longcst (vec->tokens[i].length);
415 memcpy (&expout->elts[expout_ptr], vec->tokens[i].ptr,
416 vec->tokens[i].length);
417 expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
420 write_exp_elt_longcst (len);
421 write_exp_elt_opcode (OP_STRING);
424 /* Add a bitstring constant to the end of the expression.
426 Bitstring constants are stored by first writing an expression element
427 that contains the length of the bitstring (in bits), then stuffing the
428 bitstring constant itself into however many expression elements are
429 needed to hold it, and then writing another expression element that
430 contains the length of the bitstring. I.e. an expression element at
431 each end of the bitstring records the bitstring length, so you can skip
432 over the expression elements containing the actual bitstring bytes from
433 either end of the bitstring. */
436 write_exp_bitstring (struct stoken str)
438 int bits = str.length; /* length in bits */
439 int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
443 /* Compute the number of expression elements required to hold the bitstring,
444 along with one expression element at each end to record the actual
445 bitstring length in bits. */
447 lenelt = 2 + BYTES_TO_EXP_ELEM (len);
449 /* Ensure that we have enough available expression elements to store
452 if ((expout_ptr + lenelt) >= expout_size)
454 expout_size = max (expout_size * 2, expout_ptr + lenelt + 10);
455 expout = (struct expression *)
456 xrealloc ((char *) expout, (sizeof (struct expression)
457 + EXP_ELEM_TO_BYTES (expout_size)));
460 /* Write the leading length expression element (which advances the current
461 expression element index), then write the bitstring constant, and then
462 write the trailing length expression element. */
464 write_exp_elt_longcst ((LONGEST) bits);
465 strdata = (char *) &expout->elts[expout_ptr];
466 memcpy (strdata, str.ptr, len);
467 expout_ptr += lenelt - 2;
468 write_exp_elt_longcst ((LONGEST) bits);
471 /* Add the appropriate elements for a minimal symbol to the end of
475 write_exp_msymbol (struct minimal_symbol *msymbol)
477 struct objfile *objfile = msymbol_objfile (msymbol);
478 struct gdbarch *gdbarch = get_objfile_arch (objfile);
480 CORE_ADDR addr = SYMBOL_VALUE_ADDRESS (msymbol);
481 struct obj_section *section = SYMBOL_OBJ_SECTION (msymbol);
482 enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
485 /* The minimal symbol might point to a function descriptor;
486 resolve it to the actual code address instead. */
487 pc = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, ¤t_target);
490 struct minimal_symbol *ifunc_msym = lookup_minimal_symbol_by_pc (pc);
492 /* In this case, assume we have a code symbol instead of
495 if (ifunc_msym != NULL && MSYMBOL_TYPE (ifunc_msym) == mst_text_gnu_ifunc
496 && SYMBOL_VALUE_ADDRESS (ifunc_msym) == pc)
498 /* A function descriptor has been resolved but PC is still in the
499 STT_GNU_IFUNC resolver body (such as because inferior does not
500 run to be able to call it). */
502 type = mst_text_gnu_ifunc;
510 if (overlay_debugging)
511 addr = symbol_overlayed_address (addr, section);
513 write_exp_elt_opcode (OP_LONG);
514 /* Let's make the type big enough to hold a 64-bit address. */
515 write_exp_elt_type (objfile_type (objfile)->builtin_core_addr);
516 write_exp_elt_longcst ((LONGEST) addr);
517 write_exp_elt_opcode (OP_LONG);
519 if (section && section->the_bfd_section->flags & SEC_THREAD_LOCAL)
521 write_exp_elt_opcode (UNOP_MEMVAL_TLS);
522 write_exp_elt_objfile (objfile);
523 write_exp_elt_type (objfile_type (objfile)->nodebug_tls_symbol);
524 write_exp_elt_opcode (UNOP_MEMVAL_TLS);
528 write_exp_elt_opcode (UNOP_MEMVAL);
533 case mst_solib_trampoline:
534 write_exp_elt_type (objfile_type (objfile)->nodebug_text_symbol);
537 case mst_text_gnu_ifunc:
538 write_exp_elt_type (objfile_type (objfile)
539 ->nodebug_text_gnu_ifunc_symbol);
546 write_exp_elt_type (objfile_type (objfile)->nodebug_data_symbol);
549 case mst_slot_got_plt:
550 write_exp_elt_type (objfile_type (objfile)->nodebug_got_plt_symbol);
554 write_exp_elt_type (objfile_type (objfile)->nodebug_unknown_symbol);
557 write_exp_elt_opcode (UNOP_MEMVAL);
560 /* Mark the current index as the starting location of a structure
561 expression. This is used when completing on field names. */
564 mark_struct_expression (void)
566 expout_last_struct = expout_ptr;
570 /* Recognize tokens that start with '$'. These include:
572 $regname A native register name or a "standard
575 $variable A convenience variable with a name chosen
578 $digits Value history with index <digits>, starting
579 from the first value which has index 1.
581 $$digits Value history with index <digits> relative
582 to the last value. I.e. $$0 is the last
583 value, $$1 is the one previous to that, $$2
584 is the one previous to $$1, etc.
586 $ | $0 | $$0 The last value in the value history.
588 $$ An abbreviation for the second to the last
589 value in the value history, I.e. $$1 */
592 write_dollar_variable (struct stoken str)
594 struct symbol *sym = NULL;
595 struct minimal_symbol *msym = NULL;
596 struct internalvar *isym = NULL;
598 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
599 and $$digits (equivalent to $<-digits> if you could type that). */
603 /* Double dollar means negate the number and add -1 as well.
604 Thus $$ alone means -1. */
605 if (str.length >= 2 && str.ptr[1] == '$')
612 /* Just dollars (one or two). */
616 /* Is the rest of the token digits? */
617 for (; i < str.length; i++)
618 if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
622 i = atoi (str.ptr + 1 + negate);
628 /* Handle tokens that refer to machine registers:
629 $ followed by a register name. */
630 i = user_reg_map_name_to_regnum (parse_gdbarch,
631 str.ptr + 1, str.length - 1);
633 goto handle_register;
635 /* Any names starting with $ are probably debugger internal variables. */
637 isym = lookup_only_internalvar (copy_name (str) + 1);
640 write_exp_elt_opcode (OP_INTERNALVAR);
641 write_exp_elt_intern (isym);
642 write_exp_elt_opcode (OP_INTERNALVAR);
646 /* On some systems, such as HP-UX and hppa-linux, certain system routines
647 have names beginning with $ or $$. Check for those, first. */
649 sym = lookup_symbol (copy_name (str), (struct block *) NULL,
650 VAR_DOMAIN, (int *) NULL);
653 write_exp_elt_opcode (OP_VAR_VALUE);
654 write_exp_elt_block (block_found); /* set by lookup_symbol */
655 write_exp_elt_sym (sym);
656 write_exp_elt_opcode (OP_VAR_VALUE);
659 msym = lookup_minimal_symbol (copy_name (str), NULL, NULL);
662 write_exp_msymbol (msym);
666 /* Any other names are assumed to be debugger internal variables. */
668 write_exp_elt_opcode (OP_INTERNALVAR);
669 write_exp_elt_intern (create_internalvar (copy_name (str) + 1));
670 write_exp_elt_opcode (OP_INTERNALVAR);
673 write_exp_elt_opcode (OP_LAST);
674 write_exp_elt_longcst ((LONGEST) i);
675 write_exp_elt_opcode (OP_LAST);
678 write_exp_elt_opcode (OP_REGISTER);
681 write_exp_string (str);
682 write_exp_elt_opcode (OP_REGISTER);
688 find_template_name_end (char *p)
691 int just_seen_right = 0;
692 int just_seen_colon = 0;
693 int just_seen_space = 0;
695 if (!p || (*p != '<'))
706 /* In future, may want to allow these?? */
709 depth++; /* start nested template */
710 if (just_seen_colon || just_seen_right || just_seen_space)
711 return 0; /* but not after : or :: or > or space */
714 if (just_seen_colon || just_seen_right)
715 return 0; /* end a (nested?) template */
716 just_seen_right = 1; /* but not after : or :: */
717 if (--depth == 0) /* also disallow >>, insist on > > */
718 return ++p; /* if outermost ended, return */
721 if (just_seen_space || (just_seen_colon > 1))
722 return 0; /* nested class spec coming up */
723 just_seen_colon++; /* we allow :: but not :::: */
728 if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
729 (*p >= 'A' && *p <= 'Z') ||
730 (*p >= '0' && *p <= '9') ||
731 (*p == '_') || (*p == ',') || /* commas for template args */
732 (*p == '&') || (*p == '*') || /* pointer and ref types */
733 (*p == '(') || (*p == ')') || /* function types */
734 (*p == '[') || (*p == ']'))) /* array types */
749 /* Return a null-terminated temporary copy of the name
750 of a string token. */
753 copy_name (struct stoken token)
755 /* Make sure there's enough space for the token. */
756 if (namecopy_size < token.length + 1)
758 namecopy_size = token.length + 1;
759 namecopy = xrealloc (namecopy, token.length + 1);
762 memcpy (namecopy, token.ptr, token.length);
763 namecopy[token.length] = 0;
768 /* Reverse an expression from suffix form (in which it is constructed)
769 to prefix form (in which we can conveniently print or execute it).
770 Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT
771 is not -1 (i.e., we are trying to complete a field name), it will
772 return the index of the subexpression which is the left-hand-side
773 of the struct operation at EXPOUT_LAST_STRUCT. */
776 prefixify_expression (struct expression *expr)
778 int len = sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts);
779 struct expression *temp;
780 int inpos = expr->nelts, outpos = 0;
782 temp = (struct expression *) alloca (len);
784 /* Copy the original expression into temp. */
785 memcpy (temp, expr, len);
787 return prefixify_subexp (temp, expr, inpos, outpos);
790 /* Return the number of exp_elements in the postfix subexpression
791 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
794 length_of_subexp (struct expression *expr, int endpos)
798 operator_length (expr, endpos, &oplen, &args);
802 oplen += length_of_subexp (expr, endpos - oplen);
809 /* Sets *OPLENP to the length of the operator whose (last) index is
810 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
814 operator_length (const struct expression *expr, int endpos, int *oplenp,
817 expr->language_defn->la_exp_desc->operator_length (expr, endpos,
821 /* Default value for operator_length in exp_descriptor vectors. */
824 operator_length_standard (const struct expression *expr, int endpos,
825 int *oplenp, int *argsp)
829 enum f90_range_type range_type;
833 error (_("?error in operator_length_standard"));
835 i = (int) expr->elts[endpos - 1].opcode;
841 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
842 oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
865 case OP_F77_UNDETERMINED_ARGLIST:
867 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
871 oplen = 4 + longest_to_int (expr->elts[endpos - 2].longconst);
875 case OP_OBJC_MSGCALL: /* Objective C message (method) call. */
877 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
887 case UNOP_DYNAMIC_CAST:
888 case UNOP_REINTERPRET_CAST:
894 case UNOP_MEMVAL_TLS:
912 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
913 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
919 case STRUCTOP_STRUCT:
926 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
927 NSString constant. */
928 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
930 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
931 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
935 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
936 oplen = (oplen + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
937 oplen = 4 + BYTES_TO_EXP_ELEM (oplen);
942 args = longest_to_int (expr->elts[endpos - 2].longconst);
943 args -= longest_to_int (expr->elts[endpos - 3].longconst);
949 case TERNOP_SLICE_COUNT:
954 case MULTI_SUBSCRIPT:
956 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
959 case BINOP_ASSIGN_MODIFY:
972 range_type = longest_to_int (expr->elts[endpos - 2].longconst);
975 case LOW_BOUND_DEFAULT:
976 case HIGH_BOUND_DEFAULT:
979 case BOTH_BOUND_DEFAULT:
982 case NONE_BOUND_DEFAULT:
990 args = 1 + (i < (int) BINOP_END);
997 /* Copy the subexpression ending just before index INEND in INEXPR
998 into OUTEXPR, starting at index OUTBEG.
999 In the process, convert it from suffix to prefix form.
1000 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1001 Otherwise, it returns the index of the subexpression which is the
1002 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1005 prefixify_subexp (struct expression *inexpr,
1006 struct expression *outexpr, int inend, int outbeg)
1014 operator_length (inexpr, inend, &oplen, &args);
1016 /* Copy the final operator itself, from the end of the input
1017 to the beginning of the output. */
1019 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1020 EXP_ELEM_TO_BYTES (oplen));
1023 if (expout_last_struct == inend)
1024 result = outbeg - oplen;
1026 /* Find the lengths of the arg subexpressions. */
1027 arglens = (int *) alloca (args * sizeof (int));
1028 for (i = args - 1; i >= 0; i--)
1030 oplen = length_of_subexp (inexpr, inend);
1035 /* Now copy each subexpression, preserving the order of
1036 the subexpressions, but prefixifying each one.
1037 In this loop, inend starts at the beginning of
1038 the expression this level is working on
1039 and marches forward over the arguments.
1040 outbeg does similarly in the output. */
1041 for (i = 0; i < args; i++)
1047 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1050 /* Return immediately. We probably have only parsed a
1051 partial expression, so we don't want to try to reverse
1052 the other operands. */
1061 /* Read an expression from the string *STRINGPTR points to,
1062 parse it, and return a pointer to a struct expression that we malloc.
1063 Use block BLOCK as the lexical context for variable names;
1064 if BLOCK is zero, use the block of the selected stack frame.
1065 Meanwhile, advance *STRINGPTR to point after the expression,
1066 at the first nonwhite character that is not part of the expression
1067 (possibly a null character).
1069 If COMMA is nonzero, stop if a comma is reached. */
1072 parse_exp_1 (char **stringptr, struct block *block, int comma)
1074 return parse_exp_in_context (stringptr, block, comma, 0, NULL);
1077 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1078 no value is expected from the expression.
1079 OUT_SUBEXP is set when attempting to complete a field name; in this
1080 case it is set to the index of the subexpression on the
1081 left-hand-side of the struct op. If not doing such completion, it
1082 is left untouched. */
1084 static struct expression *
1085 parse_exp_in_context (char **stringptr, struct block *block, int comma,
1086 int void_context_p, int *out_subexp)
1088 volatile struct gdb_exception except;
1089 struct cleanup *old_chain;
1090 const struct language_defn *lang = NULL;
1093 lexptr = *stringptr;
1097 type_stack_depth = 0;
1098 expout_last_struct = -1;
1100 comma_terminates = comma;
1102 if (lexptr == 0 || *lexptr == 0)
1103 error_no_arg (_("expression to compute"));
1105 old_chain = make_cleanup (free_funcalls, 0 /*ignore*/);
1108 expression_context_block = block;
1110 /* If no context specified, try using the current frame, if any. */
1111 if (!expression_context_block)
1112 expression_context_block = get_selected_block (&expression_context_pc);
1114 expression_context_pc = BLOCK_START (expression_context_block);
1116 /* Fall back to using the current source static context, if any. */
1118 if (!expression_context_block)
1120 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1122 expression_context_block
1123 = BLOCKVECTOR_BLOCK (BLOCKVECTOR (cursal.symtab), STATIC_BLOCK);
1124 if (expression_context_block)
1125 expression_context_pc = BLOCK_START (expression_context_block);
1128 if (language_mode == language_mode_auto && block != NULL)
1130 /* Find the language associated to the given context block.
1131 Default to the current language if it can not be determined.
1133 Note that using the language corresponding to the current frame
1134 can sometimes give unexpected results. For instance, this
1135 routine is often called several times during the inferior
1136 startup phase to re-parse breakpoint expressions after
1137 a new shared library has been loaded. The language associated
1138 to the current frame at this moment is not relevant for
1139 the breakpoint. Using it would therefore be silly, so it seems
1140 better to rely on the current language rather than relying on
1141 the current frame language to parse the expression. That's why
1142 we do the following language detection only if the context block
1143 has been specifically provided. */
1144 struct symbol *func = block_linkage_function (block);
1147 lang = language_def (SYMBOL_LANGUAGE (func));
1148 if (lang == NULL || lang->la_language == language_unknown)
1149 lang = current_language;
1152 lang = current_language;
1156 expout = (struct expression *)
1157 xmalloc (sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size));
1158 expout->language_defn = lang;
1159 expout->gdbarch = get_current_arch ();
1161 TRY_CATCH (except, RETURN_MASK_ALL)
1163 if (lang->la_parser ())
1164 lang->la_error (NULL);
1166 if (except.reason < 0)
1168 if (! in_parse_field)
1171 throw_exception (except);
1175 discard_cleanups (old_chain);
1177 /* Record the actual number of expression elements, and then
1178 reallocate the expression memory so that we free up any
1181 expout->nelts = expout_ptr;
1182 expout = (struct expression *)
1183 xrealloc ((char *) expout,
1184 sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_ptr));
1186 /* Convert expression from postfix form as generated by yacc
1187 parser, to a prefix form. */
1189 if (expressiondebug)
1190 dump_raw_expression (expout, gdb_stdlog,
1191 "before conversion to prefix form");
1193 subexp = prefixify_expression (expout);
1195 *out_subexp = subexp;
1197 lang->la_post_parser (&expout, void_context_p);
1199 if (expressiondebug)
1200 dump_prefix_expression (expout, gdb_stdlog);
1202 *stringptr = lexptr;
1206 /* Parse STRING as an expression, and complain if this fails
1207 to use up all of the contents of STRING. */
1210 parse_expression (char *string)
1212 struct expression *exp;
1214 exp = parse_exp_1 (&string, 0, 0);
1216 error (_("Junk after end of expression."));
1220 /* Parse STRING as an expression. If parsing ends in the middle of a
1221 field reference, return the type of the left-hand-side of the
1222 reference; furthermore, if the parsing ends in the field name,
1223 return the field name in *NAME. If the parsing ends in the middle
1224 of a field reference, but the reference is somehow invalid, throw
1225 an exception. In all other cases, return NULL. Returned non-NULL
1226 *NAME must be freed by the caller. */
1229 parse_field_expression (char *string, char **name)
1231 struct expression *exp = NULL;
1234 volatile struct gdb_exception except;
1236 TRY_CATCH (except, RETURN_MASK_ERROR)
1239 exp = parse_exp_in_context (&string, 0, 0, 0, &subexp);
1242 if (except.reason < 0 || ! exp)
1244 if (expout_last_struct == -1)
1250 *name = extract_field_op (exp, &subexp);
1257 /* This might throw an exception. If so, we want to let it
1259 val = evaluate_subexpression_type (exp, subexp);
1260 /* (*NAME) is a part of the EXP memory block freed below. */
1261 *name = xstrdup (*name);
1264 return value_type (val);
1267 /* A post-parser that does nothing. */
1270 null_post_parser (struct expression **exp, int void_context_p)
1274 /* Parse floating point value P of length LEN.
1275 Return 0 (false) if invalid, 1 (true) if valid.
1276 The successfully parsed number is stored in D.
1277 *SUFFIX points to the suffix of the number in P.
1279 NOTE: This accepts the floating point syntax that sscanf accepts. */
1282 parse_float (const char *p, int len, DOUBLEST *d, const char **suffix)
1288 copy = xmalloc (len + 1);
1289 memcpy (copy, p, len);
1292 num = sscanf (copy, "%" DOUBLEST_SCAN_FORMAT "%n", d, &n);
1295 /* The sscanf man page suggests not making any assumptions on the effect
1296 of %n on the result, so we don't.
1297 That is why we simply test num == 0. */
1305 /* Parse floating point value P of length LEN, using the C syntax for floats.
1306 Return 0 (false) if invalid, 1 (true) if valid.
1307 The successfully parsed number is stored in *D.
1308 Its type is taken from builtin_type (gdbarch) and is stored in *T. */
1311 parse_c_float (struct gdbarch *gdbarch, const char *p, int len,
1312 DOUBLEST *d, struct type **t)
1316 const struct builtin_type *builtin_types = builtin_type (gdbarch);
1318 if (! parse_float (p, len, d, &suffix))
1321 suffix_len = p + len - suffix;
1323 if (suffix_len == 0)
1324 *t = builtin_types->builtin_double;
1325 else if (suffix_len == 1)
1327 /* Handle suffixes: 'f' for float, 'l' for long double. */
1328 if (tolower (*suffix) == 'f')
1329 *t = builtin_types->builtin_float;
1330 else if (tolower (*suffix) == 'l')
1331 *t = builtin_types->builtin_long_double;
1341 /* Stuff for maintaining a stack of types. Currently just used by C, but
1342 probably useful for any language which declares its types "backwards". */
1345 check_type_stack_depth (void)
1347 if (type_stack_depth == type_stack_size)
1349 type_stack_size *= 2;
1350 type_stack = (union type_stack_elt *)
1351 xrealloc ((char *) type_stack, type_stack_size * sizeof (*type_stack));
1356 push_type (enum type_pieces tp)
1358 check_type_stack_depth ();
1359 type_stack[type_stack_depth++].piece = tp;
1363 push_type_int (int n)
1365 check_type_stack_depth ();
1366 type_stack[type_stack_depth++].int_val = n;
1370 push_type_address_space (char *string)
1372 push_type_int (address_space_name_to_int (parse_gdbarch, string));
1378 if (type_stack_depth)
1379 return type_stack[--type_stack_depth].piece;
1386 if (type_stack_depth)
1387 return type_stack[--type_stack_depth].int_val;
1388 /* "Can't happen". */
1392 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1393 as modified by all the stuff on the stack. */
1395 follow_types (struct type *follow_type)
1399 int make_volatile = 0;
1400 int make_addr_space = 0;
1404 switch (pop_type ())
1409 follow_type = make_cv_type (make_const,
1410 TYPE_VOLATILE (follow_type),
1413 follow_type = make_cv_type (TYPE_CONST (follow_type),
1416 if (make_addr_space)
1417 follow_type = make_type_with_address_space (follow_type,
1419 make_const = make_volatile = 0;
1420 make_addr_space = 0;
1428 case tp_space_identifier:
1429 make_addr_space = pop_type_int ();
1432 follow_type = lookup_pointer_type (follow_type);
1434 follow_type = make_cv_type (make_const,
1435 TYPE_VOLATILE (follow_type),
1438 follow_type = make_cv_type (TYPE_CONST (follow_type),
1441 if (make_addr_space)
1442 follow_type = make_type_with_address_space (follow_type,
1444 make_const = make_volatile = 0;
1445 make_addr_space = 0;
1448 follow_type = lookup_reference_type (follow_type);
1450 follow_type = make_cv_type (make_const,
1451 TYPE_VOLATILE (follow_type),
1454 follow_type = make_cv_type (TYPE_CONST (follow_type),
1457 if (make_addr_space)
1458 follow_type = make_type_with_address_space (follow_type,
1460 make_const = make_volatile = 0;
1461 make_addr_space = 0;
1464 array_size = pop_type_int ();
1465 /* FIXME-type-allocation: need a way to free this type when we are
1468 lookup_array_range_type (follow_type,
1469 0, array_size >= 0 ? array_size - 1 : 0);
1471 TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (follow_type) = 1;
1474 /* FIXME-type-allocation: need a way to free this type when we are
1476 follow_type = lookup_function_type (follow_type);
1482 /* This function avoids direct calls to fprintf
1483 in the parser generated debug code. */
1485 parser_fprintf (FILE *x, const char *y, ...)
1491 vfprintf_unfiltered (gdb_stderr, y, args);
1494 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1495 vfprintf_unfiltered (gdb_stderr, y, args);
1500 /* Implementation of the exp_descriptor method operator_check. */
1503 operator_check_standard (struct expression *exp, int pos,
1504 int (*objfile_func) (struct objfile *objfile,
1508 const union exp_element *const elts = exp->elts;
1509 struct type *type = NULL;
1510 struct objfile *objfile = NULL;
1512 /* Extended operators should have been already handled by exp_descriptor
1513 iterate method of its specific language. */
1514 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1516 /* Track the callers of write_exp_elt_type for this table. */
1518 switch (elts[pos].opcode)
1528 case UNOP_DYNAMIC_CAST:
1529 case UNOP_REINTERPRET_CAST:
1533 type = elts[pos + 1].type;
1538 LONGEST arg, nargs = elts[pos + 1].longconst;
1540 for (arg = 0; arg < nargs; arg++)
1542 struct type *type = elts[pos + 2 + arg].type;
1543 struct objfile *objfile = TYPE_OBJFILE (type);
1545 if (objfile && (*objfile_func) (objfile, data))
1551 case UNOP_MEMVAL_TLS:
1552 objfile = elts[pos + 1].objfile;
1553 type = elts[pos + 2].type;
1558 const struct block *const block = elts[pos + 1].block;
1559 const struct symbol *const symbol = elts[pos + 2].symbol;
1561 /* Check objfile where the variable itself is placed.
1562 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1563 if ((*objfile_func) (SYMBOL_SYMTAB (symbol)->objfile, data))
1566 /* Check objfile where is placed the code touching the variable. */
1567 objfile = lookup_objfile_from_block (block);
1569 type = SYMBOL_TYPE (symbol);
1574 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1576 if (type && TYPE_OBJFILE (type)
1577 && (*objfile_func) (TYPE_OBJFILE (type), data))
1579 if (objfile && (*objfile_func) (objfile, data))
1585 /* Call OBJFILE_FUNC for any TYPE and OBJFILE found being referenced by EXP.
1586 The functions are never called with NULL OBJFILE. Functions get passed an
1587 arbitrary caller supplied DATA pointer. If any of the functions returns
1588 non-zero value then (any other) non-zero value is immediately returned to
1589 the caller. Otherwise zero is returned after iterating through whole EXP.
1593 exp_iterate (struct expression *exp,
1594 int (*objfile_func) (struct objfile *objfile, void *data),
1599 for (endpos = exp->nelts; endpos > 0; )
1601 int pos, args, oplen = 0;
1603 operator_length (exp, endpos, &oplen, &args);
1604 gdb_assert (oplen > 0);
1606 pos = endpos - oplen;
1607 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1608 objfile_func, data))
1617 /* Helper for exp_uses_objfile. */
1620 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1622 struct objfile *objfile = objfile_voidp;
1624 if (exp_objfile->separate_debug_objfile_backlink)
1625 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1627 return exp_objfile == objfile;
1630 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1631 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1635 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1637 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1639 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1643 _initialize_parse (void)
1645 type_stack_size = 80;
1646 type_stack_depth = 0;
1647 type_stack = (union type_stack_elt *)
1648 xmalloc (type_stack_size * sizeof (*type_stack));
1650 add_setshow_zinteger_cmd ("expression", class_maintenance,
1652 _("Set expression debugging."),
1653 _("Show expression debugging."),
1654 _("When non-zero, the internal representation "
1655 "of expressions will be printed."),
1657 show_expressiondebug,
1658 &setdebuglist, &showdebuglist);
1659 add_setshow_boolean_cmd ("parser", class_maintenance,
1661 _("Set parser debugging."),
1662 _("Show parser debugging."),
1663 _("When non-zero, expression parser "
1664 "tracing will be enabled."),
1667 &setdebuglist, &showdebuglist);