| /* Parse expressions for GDB. |
| |
| Copyright (C) 1986-2020 Free Software Foundation, Inc. |
| |
| Modified from expread.y by the Department of Computer Science at the |
| State University of New York at Buffalo, 1991. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| /* Parse an expression from text in a string, |
| and return the result as a struct expression pointer. |
| That structure contains arithmetic operations in reverse polish, |
| with constants represented by operations that are followed by special data. |
| See expression.h for the details of the format. |
| What is important here is that it can be built up sequentially |
| during the process of parsing; the lower levels of the tree always |
| come first in the result. */ |
| |
| #include "defs.h" |
| #include <ctype.h> |
| #include "arch-utils.h" |
| #include "symtab.h" |
| #include "gdbtypes.h" |
| #include "frame.h" |
| #include "expression.h" |
| #include "value.h" |
| #include "command.h" |
| #include "language.h" |
| #include "f-lang.h" |
| #include "parser-defs.h" |
| #include "gdbcmd.h" |
| #include "symfile.h" /* for overlay functions */ |
| #include "inferior.h" |
| #include "target-float.h" |
| #include "block.h" |
| #include "source.h" |
| #include "objfiles.h" |
| #include "user-regs.h" |
| #include <algorithm> |
| #include "gdbsupport/gdb_optional.h" |
| |
| /* Standard set of definitions for printing, dumping, prefixifying, |
| * and evaluating expressions. */ |
| |
| const struct exp_descriptor exp_descriptor_standard = |
| { |
| print_subexp_standard, |
| operator_length_standard, |
| operator_check_standard, |
| op_name_standard, |
| dump_subexp_body_standard, |
| evaluate_subexp_standard |
| }; |
| |
| static unsigned int expressiondebug = 0; |
| static void |
| show_expressiondebug (struct ui_file *file, int from_tty, |
| struct cmd_list_element *c, const char *value) |
| { |
| fprintf_filtered (file, _("Expression debugging is %s.\n"), value); |
| } |
| |
| |
| /* True if an expression parser should set yydebug. */ |
| bool parser_debug; |
| |
| static void |
| show_parserdebug (struct ui_file *file, int from_tty, |
| struct cmd_list_element *c, const char *value) |
| { |
| fprintf_filtered (file, _("Parser debugging is %s.\n"), value); |
| } |
| |
| |
| static int prefixify_subexp (struct expression *, struct expression *, int, |
| int, int); |
| |
| static expression_up parse_exp_in_context (const char **, CORE_ADDR, |
| const struct block *, int, |
| int, int *, |
| innermost_block_tracker *, |
| expr_completion_state *); |
| |
| static void increase_expout_size (struct expr_builder *ps, size_t lenelt); |
| |
| |
| /* Documented at it's declaration. */ |
| |
| void |
| innermost_block_tracker::update (const struct block *b, |
| innermost_block_tracker_types t) |
| { |
| if ((m_types & t) != 0 |
| && (m_innermost_block == NULL |
| || contained_in (b, m_innermost_block))) |
| m_innermost_block = b; |
| } |
| |
| |
| |
| /* See definition in parser-defs.h. */ |
| |
| expr_builder::expr_builder (const struct language_defn *lang, |
| struct gdbarch *gdbarch) |
| : expout_size (10), |
| expout (XNEWVAR (expression, |
| (sizeof (expression) |
| + EXP_ELEM_TO_BYTES (expout_size)))), |
| expout_ptr (0) |
| { |
| expout->language_defn = lang; |
| expout->gdbarch = gdbarch; |
| } |
| |
| expression_up |
| expr_builder::release () |
| { |
| /* Record the actual number of expression elements, and then |
| reallocate the expression memory so that we free up any |
| excess elements. */ |
| |
| expout->nelts = expout_ptr; |
| expout.reset (XRESIZEVAR (expression, expout.release (), |
| (sizeof (expression) |
| + EXP_ELEM_TO_BYTES (expout_ptr)))); |
| |
| return std::move (expout); |
| } |
| |
| /* This page contains the functions for adding data to the struct expression |
| being constructed. */ |
| |
| /* Add one element to the end of the expression. */ |
| |
| /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into |
| a register through here. */ |
| |
| static void |
| write_exp_elt (struct expr_builder *ps, const union exp_element *expelt) |
| { |
| if (ps->expout_ptr >= ps->expout_size) |
| { |
| ps->expout_size *= 2; |
| ps->expout.reset (XRESIZEVAR (expression, ps->expout.release (), |
| (sizeof (expression) |
| + EXP_ELEM_TO_BYTES (ps->expout_size)))); |
| } |
| ps->expout->elts[ps->expout_ptr++] = *expelt; |
| } |
| |
| void |
| write_exp_elt_opcode (struct expr_builder *ps, enum exp_opcode expelt) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.opcode = expelt; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| void |
| write_exp_elt_sym (struct expr_builder *ps, struct symbol *expelt) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.symbol = expelt; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| static void |
| write_exp_elt_msym (struct expr_builder *ps, minimal_symbol *expelt) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.msymbol = expelt; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| void |
| write_exp_elt_block (struct expr_builder *ps, const struct block *b) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.block = b; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| void |
| write_exp_elt_objfile (struct expr_builder *ps, struct objfile *objfile) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.objfile = objfile; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| void |
| write_exp_elt_longcst (struct expr_builder *ps, LONGEST expelt) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.longconst = expelt; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| void |
| write_exp_elt_floatcst (struct expr_builder *ps, const gdb_byte expelt[16]) |
| { |
| union exp_element tmp; |
| int index; |
| |
| for (index = 0; index < 16; index++) |
| tmp.floatconst[index] = expelt[index]; |
| |
| write_exp_elt (ps, &tmp); |
| } |
| |
| void |
| write_exp_elt_type (struct expr_builder *ps, struct type *expelt) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.type = expelt; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| void |
| write_exp_elt_intern (struct expr_builder *ps, struct internalvar *expelt) |
| { |
| union exp_element tmp; |
| |
| memset (&tmp, 0, sizeof (union exp_element)); |
| tmp.internalvar = expelt; |
| write_exp_elt (ps, &tmp); |
| } |
| |
| /* Add a string constant to the end of the expression. |
| |
| String constants are stored by first writing an expression element |
| that contains the length of the string, then stuffing the string |
| constant itself into however many expression elements are needed |
| to hold it, and then writing another expression element that contains |
| the length of the string. I.e. an expression element at each end of |
| the string records the string length, so you can skip over the |
| expression elements containing the actual string bytes from either |
| end of the string. Note that this also allows gdb to handle |
| strings with embedded null bytes, as is required for some languages. |
| |
| Don't be fooled by the fact that the string is null byte terminated, |
| this is strictly for the convenience of debugging gdb itself. |
| Gdb does not depend up the string being null terminated, since the |
| actual length is recorded in expression elements at each end of the |
| string. The null byte is taken into consideration when computing how |
| many expression elements are required to hold the string constant, of |
| course. */ |
| |
| |
| void |
| write_exp_string (struct expr_builder *ps, struct stoken str) |
| { |
| int len = str.length; |
| size_t lenelt; |
| char *strdata; |
| |
| /* Compute the number of expression elements required to hold the string |
| (including a null byte terminator), along with one expression element |
| at each end to record the actual string length (not including the |
| null byte terminator). */ |
| |
| lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1); |
| |
| increase_expout_size (ps, lenelt); |
| |
| /* Write the leading length expression element (which advances the current |
| expression element index), then write the string constant followed by a |
| terminating null byte, and then write the trailing length expression |
| element. */ |
| |
| write_exp_elt_longcst (ps, (LONGEST) len); |
| strdata = (char *) &ps->expout->elts[ps->expout_ptr]; |
| memcpy (strdata, str.ptr, len); |
| *(strdata + len) = '\0'; |
| ps->expout_ptr += lenelt - 2; |
| write_exp_elt_longcst (ps, (LONGEST) len); |
| } |
| |
| /* Add a vector of string constants to the end of the expression. |
| |
| This adds an OP_STRING operation, but encodes the contents |
| differently from write_exp_string. The language is expected to |
| handle evaluation of this expression itself. |
| |
| After the usual OP_STRING header, TYPE is written into the |
| expression as a long constant. The interpretation of this field is |
| up to the language evaluator. |
| |
| Next, each string in VEC is written. The length is written as a |
| long constant, followed by the contents of the string. */ |
| |
| void |
| write_exp_string_vector (struct expr_builder *ps, int type, |
| struct stoken_vector *vec) |
| { |
| int i, len; |
| size_t n_slots; |
| |
| /* Compute the size. We compute the size in number of slots to |
| avoid issues with string padding. */ |
| n_slots = 0; |
| for (i = 0; i < vec->len; ++i) |
| { |
| /* One slot for the length of this element, plus the number of |
| slots needed for this string. */ |
| n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length); |
| } |
| |
| /* One more slot for the type of the string. */ |
| ++n_slots; |
| |
| /* Now compute a phony string length. */ |
| len = EXP_ELEM_TO_BYTES (n_slots) - 1; |
| |
| n_slots += 4; |
| increase_expout_size (ps, n_slots); |
| |
| write_exp_elt_opcode (ps, OP_STRING); |
| write_exp_elt_longcst (ps, len); |
| write_exp_elt_longcst (ps, type); |
| |
| for (i = 0; i < vec->len; ++i) |
| { |
| write_exp_elt_longcst (ps, vec->tokens[i].length); |
| memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr, |
| vec->tokens[i].length); |
| ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length); |
| } |
| |
| write_exp_elt_longcst (ps, len); |
| write_exp_elt_opcode (ps, OP_STRING); |
| } |
| |
| /* Add a bitstring constant to the end of the expression. |
| |
| Bitstring constants are stored by first writing an expression element |
| that contains the length of the bitstring (in bits), then stuffing the |
| bitstring constant itself into however many expression elements are |
| needed to hold it, and then writing another expression element that |
| contains the length of the bitstring. I.e. an expression element at |
| each end of the bitstring records the bitstring length, so you can skip |
| over the expression elements containing the actual bitstring bytes from |
| either end of the bitstring. */ |
| |
| void |
| write_exp_bitstring (struct expr_builder *ps, struct stoken str) |
| { |
| int bits = str.length; /* length in bits */ |
| int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT; |
| size_t lenelt; |
| char *strdata; |
| |
| /* Compute the number of expression elements required to hold the bitstring, |
| along with one expression element at each end to record the actual |
| bitstring length in bits. */ |
| |
| lenelt = 2 + BYTES_TO_EXP_ELEM (len); |
| |
| increase_expout_size (ps, lenelt); |
| |
| /* Write the leading length expression element (which advances the current |
| expression element index), then write the bitstring constant, and then |
| write the trailing length expression element. */ |
| |
| write_exp_elt_longcst (ps, (LONGEST) bits); |
| strdata = (char *) &ps->expout->elts[ps->expout_ptr]; |
| memcpy (strdata, str.ptr, len); |
| ps->expout_ptr += lenelt - 2; |
| write_exp_elt_longcst (ps, (LONGEST) bits); |
| } |
| |
| /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If |
| ADDRESS_P is not NULL, set it to the MSYMBOL's resolved |
| address. */ |
| |
| type * |
| find_minsym_type_and_address (minimal_symbol *msymbol, |
| struct objfile *objfile, |
| CORE_ADDR *address_p) |
| { |
| bound_minimal_symbol bound_msym = {msymbol, objfile}; |
| struct obj_section *section = MSYMBOL_OBJ_SECTION (objfile, msymbol); |
| enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol); |
| |
| bool is_tls = (section != NULL |
| && section->the_bfd_section->flags & SEC_THREAD_LOCAL); |
| |
| /* The minimal symbol might point to a function descriptor; |
| resolve it to the actual code address instead. */ |
| CORE_ADDR addr; |
| if (is_tls) |
| { |
| /* Addresses of TLS symbols are really offsets into a |
| per-objfile/per-thread storage block. */ |
| addr = MSYMBOL_VALUE_RAW_ADDRESS (bound_msym.minsym); |
| } |
| else if (msymbol_is_function (objfile, msymbol, &addr)) |
| { |
| if (addr != BMSYMBOL_VALUE_ADDRESS (bound_msym)) |
| { |
| /* This means we resolved a function descriptor, and we now |
| have an address for a code/text symbol instead of a data |
| symbol. */ |
| if (MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc) |
| type = mst_text_gnu_ifunc; |
| else |
| type = mst_text; |
| section = NULL; |
| } |
| } |
| else |
| addr = BMSYMBOL_VALUE_ADDRESS (bound_msym); |
| |
| if (overlay_debugging) |
| addr = symbol_overlayed_address (addr, section); |
| |
| if (is_tls) |
| { |
| /* Skip translation if caller does not need the address. */ |
| if (address_p != NULL) |
| *address_p = target_translate_tls_address (objfile, addr); |
| return objfile_type (objfile)->nodebug_tls_symbol; |
| } |
| |
| if (address_p != NULL) |
| *address_p = addr; |
| |
| switch (type) |
| { |
| case mst_text: |
| case mst_file_text: |
| case mst_solib_trampoline: |
| return objfile_type (objfile)->nodebug_text_symbol; |
| |
| case mst_text_gnu_ifunc: |
| return objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol; |
| |
| case mst_data: |
| case mst_file_data: |
| case mst_bss: |
| case mst_file_bss: |
| return objfile_type (objfile)->nodebug_data_symbol; |
| |
| case mst_slot_got_plt: |
| return objfile_type (objfile)->nodebug_got_plt_symbol; |
| |
| default: |
| return objfile_type (objfile)->nodebug_unknown_symbol; |
| } |
| } |
| |
| /* Add the appropriate elements for a minimal symbol to the end of |
| the expression. */ |
| |
| void |
| write_exp_msymbol (struct expr_builder *ps, |
| struct bound_minimal_symbol bound_msym) |
| { |
| write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE); |
| write_exp_elt_objfile (ps, bound_msym.objfile); |
| write_exp_elt_msym (ps, bound_msym.minsym); |
| write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE); |
| } |
| |
| /* See parser-defs.h. */ |
| |
| void |
| parser_state::mark_struct_expression () |
| { |
| gdb_assert (parse_completion |
| && (m_completion_state.expout_tag_completion_type |
| == TYPE_CODE_UNDEF)); |
| m_completion_state.expout_last_struct = expout_ptr; |
| } |
| |
| /* Indicate that the current parser invocation is completing a tag. |
| TAG is the type code of the tag, and PTR and LENGTH represent the |
| start of the tag name. */ |
| |
| void |
| parser_state::mark_completion_tag (enum type_code tag, const char *ptr, |
| int length) |
| { |
| gdb_assert (parse_completion |
| && (m_completion_state.expout_tag_completion_type |
| == TYPE_CODE_UNDEF) |
| && m_completion_state.expout_completion_name == NULL |
| && m_completion_state.expout_last_struct == -1); |
| gdb_assert (tag == TYPE_CODE_UNION |
| || tag == TYPE_CODE_STRUCT |
| || tag == TYPE_CODE_ENUM); |
| m_completion_state.expout_tag_completion_type = tag; |
| m_completion_state.expout_completion_name.reset (xstrndup (ptr, length)); |
| } |
| |
| |
| /* Recognize tokens that start with '$'. These include: |
| |
| $regname A native register name or a "standard |
| register name". |
| |
| $variable A convenience variable with a name chosen |
| by the user. |
| |
| $digits Value history with index <digits>, starting |
| from the first value which has index 1. |
| |
| $$digits Value history with index <digits> relative |
| to the last value. I.e. $$0 is the last |
| value, $$1 is the one previous to that, $$2 |
| is the one previous to $$1, etc. |
| |
| $ | $0 | $$0 The last value in the value history. |
| |
| $$ An abbreviation for the second to the last |
| value in the value history, I.e. $$1 */ |
| |
| void |
| write_dollar_variable (struct parser_state *ps, struct stoken str) |
| { |
| struct block_symbol sym; |
| struct bound_minimal_symbol msym; |
| struct internalvar *isym = NULL; |
| std::string copy; |
| |
| /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1) |
| and $$digits (equivalent to $<-digits> if you could type that). */ |
| |
| int negate = 0; |
| int i = 1; |
| /* Double dollar means negate the number and add -1 as well. |
| Thus $$ alone means -1. */ |
| if (str.length >= 2 && str.ptr[1] == '$') |
| { |
| negate = 1; |
| i = 2; |
| } |
| if (i == str.length) |
| { |
| /* Just dollars (one or two). */ |
| i = -negate; |
| goto handle_last; |
| } |
| /* Is the rest of the token digits? */ |
| for (; i < str.length; i++) |
| if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9')) |
| break; |
| if (i == str.length) |
| { |
| i = atoi (str.ptr + 1 + negate); |
| if (negate) |
| i = -i; |
| goto handle_last; |
| } |
| |
| /* Handle tokens that refer to machine registers: |
| $ followed by a register name. */ |
| i = user_reg_map_name_to_regnum (ps->gdbarch (), |
| str.ptr + 1, str.length - 1); |
| if (i >= 0) |
| goto handle_register; |
| |
| /* Any names starting with $ are probably debugger internal variables. */ |
| |
| copy = copy_name (str); |
| isym = lookup_only_internalvar (copy.c_str () + 1); |
| if (isym) |
| { |
| write_exp_elt_opcode (ps, OP_INTERNALVAR); |
| write_exp_elt_intern (ps, isym); |
| write_exp_elt_opcode (ps, OP_INTERNALVAR); |
| return; |
| } |
| |
| /* On some systems, such as HP-UX and hppa-linux, certain system routines |
| have names beginning with $ or $$. Check for those, first. */ |
| |
| sym = lookup_symbol (copy.c_str (), NULL, VAR_DOMAIN, NULL); |
| if (sym.symbol) |
| { |
| write_exp_elt_opcode (ps, OP_VAR_VALUE); |
| write_exp_elt_block (ps, sym.block); |
| write_exp_elt_sym (ps, sym.symbol); |
| write_exp_elt_opcode (ps, OP_VAR_VALUE); |
| return; |
| } |
| msym = lookup_bound_minimal_symbol (copy.c_str ()); |
| if (msym.minsym) |
| { |
| write_exp_msymbol (ps, msym); |
| return; |
| } |
| |
| /* Any other names are assumed to be debugger internal variables. */ |
| |
| write_exp_elt_opcode (ps, OP_INTERNALVAR); |
| write_exp_elt_intern (ps, create_internalvar (copy.c_str () + 1)); |
| write_exp_elt_opcode (ps, OP_INTERNALVAR); |
| return; |
| handle_last: |
| write_exp_elt_opcode (ps, OP_LAST); |
| write_exp_elt_longcst (ps, (LONGEST) i); |
| write_exp_elt_opcode (ps, OP_LAST); |
| return; |
| handle_register: |
| write_exp_elt_opcode (ps, OP_REGISTER); |
| str.length--; |
| str.ptr++; |
| write_exp_string (ps, str); |
| write_exp_elt_opcode (ps, OP_REGISTER); |
| ps->block_tracker->update (ps->expression_context_block, |
| INNERMOST_BLOCK_FOR_REGISTERS); |
| return; |
| } |
| |
| |
| const char * |
| find_template_name_end (const char *p) |
| { |
| int depth = 1; |
| int just_seen_right = 0; |
| int just_seen_colon = 0; |
| int just_seen_space = 0; |
| |
| if (!p || (*p != '<')) |
| return 0; |
| |
| while (*++p) |
| { |
| switch (*p) |
| { |
| case '\'': |
| case '\"': |
| case '{': |
| case '}': |
| /* In future, may want to allow these?? */ |
| return 0; |
| case '<': |
| depth++; /* start nested template */ |
| if (just_seen_colon || just_seen_right || just_seen_space) |
| return 0; /* but not after : or :: or > or space */ |
| break; |
| case '>': |
| if (just_seen_colon || just_seen_right) |
| return 0; /* end a (nested?) template */ |
| just_seen_right = 1; /* but not after : or :: */ |
| if (--depth == 0) /* also disallow >>, insist on > > */ |
| return ++p; /* if outermost ended, return */ |
| break; |
| case ':': |
| if (just_seen_space || (just_seen_colon > 1)) |
| return 0; /* nested class spec coming up */ |
| just_seen_colon++; /* we allow :: but not :::: */ |
| break; |
| case ' ': |
| break; |
| default: |
| if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */ |
| (*p >= 'A' && *p <= 'Z') || |
| (*p >= '0' && *p <= '9') || |
| (*p == '_') || (*p == ',') || /* commas for template args */ |
| (*p == '&') || (*p == '*') || /* pointer and ref types */ |
| (*p == '(') || (*p == ')') || /* function types */ |
| (*p == '[') || (*p == ']'))) /* array types */ |
| return 0; |
| } |
| if (*p != ' ') |
| just_seen_space = 0; |
| if (*p != ':') |
| just_seen_colon = 0; |
| if (*p != '>') |
| just_seen_right = 0; |
| } |
| return 0; |
| } |
| |
| |
| /* Return a null-terminated temporary copy of the name of a string token. |
| |
| Tokens that refer to names do so with explicit pointer and length, |
| so they can share the storage that lexptr is parsing. |
| When it is necessary to pass a name to a function that expects |
| a null-terminated string, the substring is copied out |
| into a separate block of storage. */ |
| |
| std::string |
| copy_name (struct stoken token) |
| { |
| return std::string (token.ptr, token.length); |
| } |
| |
| |
| /* See comments on parser-defs.h. */ |
| |
| int |
| prefixify_expression (struct expression *expr, int last_struct) |
| { |
| gdb_assert (expr->nelts > 0); |
| int len = sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts); |
| struct expression *temp; |
| int inpos = expr->nelts, outpos = 0; |
| |
| temp = (struct expression *) alloca (len); |
| |
| /* Copy the original expression into temp. */ |
| memcpy (temp, expr, len); |
| |
| return prefixify_subexp (temp, expr, inpos, outpos, last_struct); |
| } |
| |
| /* Return the number of exp_elements in the postfix subexpression |
| of EXPR whose operator is at index ENDPOS - 1 in EXPR. */ |
| |
| static int |
| length_of_subexp (struct expression *expr, int endpos) |
| { |
| int oplen, args; |
| |
| operator_length (expr, endpos, &oplen, &args); |
| |
| while (args > 0) |
| { |
| oplen += length_of_subexp (expr, endpos - oplen); |
| args--; |
| } |
| |
| return oplen; |
| } |
| |
| /* Sets *OPLENP to the length of the operator whose (last) index is |
| ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that |
| operator takes. */ |
| |
| void |
| operator_length (const struct expression *expr, int endpos, int *oplenp, |
| int *argsp) |
| { |
| expr->language_defn->la_exp_desc->operator_length (expr, endpos, |
| oplenp, argsp); |
| } |
| |
| /* Default value for operator_length in exp_descriptor vectors. */ |
| |
| void |
| operator_length_standard (const struct expression *expr, int endpos, |
| int *oplenp, int *argsp) |
| { |
| int oplen = 1; |
| int args = 0; |
| enum range_type range_type; |
| int i; |
| |
| if (endpos < 1) |
| error (_("?error in operator_length_standard")); |
| |
| i = (int) expr->elts[endpos - 1].opcode; |
| |
| switch (i) |
| { |
| /* C++ */ |
| case OP_SCOPE: |
| oplen = longest_to_int (expr->elts[endpos - 2].longconst); |
| oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1); |
| break; |
| |
| case OP_LONG: |
| case OP_FLOAT: |
| case OP_VAR_VALUE: |
| case OP_VAR_MSYM_VALUE: |
| oplen = 4; |
| break; |
| |
| case OP_FUNC_STATIC_VAR: |
| oplen = longest_to_int (expr->elts[endpos - 2].longconst); |
| oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1); |
| args = 1; |
| break; |
| |
| case OP_TYPE: |
| case OP_BOOL: |
| case OP_LAST: |
| case OP_INTERNALVAR: |
| case OP_VAR_ENTRY_VALUE: |
| oplen = 3; |
| break; |
| |
| case OP_COMPLEX: |
| oplen = 3; |
| args = 2; |
| break; |
| |
| case OP_FUNCALL: |
| case OP_F77_UNDETERMINED_ARGLIST: |
| oplen = 3; |
| args = 1 + longest_to_int (expr->elts[endpos - 2].longconst); |
| break; |
| |
| case TYPE_INSTANCE: |
| oplen = 5 + longest_to_int (expr->elts[endpos - 2].longconst); |
| args = 1; |
| break; |
| |
| case OP_OBJC_MSGCALL: /* Objective C message (method) call. */ |
| oplen = 4; |
| args = 1 + longest_to_int (expr->elts[endpos - 2].longconst); |
| break; |
| |
| case UNOP_MAX: |
| case UNOP_MIN: |
| oplen = 3; |
| break; |
| |
| case UNOP_CAST_TYPE: |
| case UNOP_DYNAMIC_CAST: |
| case UNOP_REINTERPRET_CAST: |
| case UNOP_MEMVAL_TYPE: |
| oplen = 1; |
| args = 2; |
| break; |
| |
| case BINOP_VAL: |
| case UNOP_CAST: |
| case UNOP_MEMVAL: |
| oplen = 3; |
| args = 1; |
| break; |
| |
| case UNOP_ABS: |
| case UNOP_CAP: |
| case UNOP_CHR: |
| case UNOP_FLOAT: |
| case UNOP_HIGH: |
| case UNOP_ODD: |
| case UNOP_ORD: |
| case UNOP_TRUNC: |
| case OP_TYPEOF: |
| case OP_DECLTYPE: |
| case OP_TYPEID: |
| oplen = 1; |
| args = 1; |
| break; |
| |
| case OP_ADL_FUNC: |
| oplen = longest_to_int (expr->elts[endpos - 2].longconst); |
| oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1); |
| oplen++; |
| oplen++; |
| break; |
| |
| case STRUCTOP_STRUCT: |
| case STRUCTOP_PTR: |
| args = 1; |
| /* fall through */ |
| case OP_REGISTER: |
| case OP_M2_STRING: |
| case OP_STRING: |
| case OP_OBJC_NSSTRING: /* Objective C Foundation Class |
| NSString constant. */ |
| case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */ |
| case OP_NAME: |
| oplen = longest_to_int (expr->elts[endpos - 2].longconst); |
| oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1); |
| break; |
| |
| case OP_ARRAY: |
| oplen = 4; |
| args = longest_to_int (expr->elts[endpos - 2].longconst); |
| args -= longest_to_int (expr->elts[endpos - 3].longconst); |
| args += 1; |
| break; |
| |
| case TERNOP_COND: |
| case TERNOP_SLICE: |
| args = 3; |
| break; |
| |
| /* Modula-2 */ |
| case MULTI_SUBSCRIPT: |
| oplen = 3; |
| args = 1 + longest_to_int (expr->elts[endpos - 2].longconst); |
| break; |
| |
| case BINOP_ASSIGN_MODIFY: |
| oplen = 3; |
| args = 2; |
| break; |
| |
| /* C++ */ |
| case OP_THIS: |
| oplen = 2; |
| break; |
| |
| case OP_RANGE: |
| oplen = 3; |
| range_type = (enum range_type) |
| longest_to_int (expr->elts[endpos - 2].longconst); |
| |
| switch (range_type) |
| { |
| case LOW_BOUND_DEFAULT: |
| case LOW_BOUND_DEFAULT_EXCLUSIVE: |
| case HIGH_BOUND_DEFAULT: |
| args = 1; |
| break; |
| case BOTH_BOUND_DEFAULT: |
| args = 0; |
| break; |
| case NONE_BOUND_DEFAULT: |
| case NONE_BOUND_DEFAULT_EXCLUSIVE: |
| args = 2; |
| break; |
| } |
| |
| break; |
| |
| default: |
| args = 1 + (i < (int) BINOP_END); |
| } |
| |
| *oplenp = oplen; |
| *argsp = args; |
| } |
| |
| /* Copy the subexpression ending just before index INEND in INEXPR |
| into OUTEXPR, starting at index OUTBEG. |
| In the process, convert it from suffix to prefix form. |
| If LAST_STRUCT is -1, then this function always returns -1. |
| Otherwise, it returns the index of the subexpression which is the |
| left-hand-side of the expression at LAST_STRUCT. */ |
| |
| static int |
| prefixify_subexp (struct expression *inexpr, |
| struct expression *outexpr, int inend, int outbeg, |
| int last_struct) |
| { |
| int oplen; |
| int args; |
| int i; |
| int *arglens; |
| int result = -1; |
| |
| operator_length (inexpr, inend, &oplen, &args); |
| |
| /* Copy the final operator itself, from the end of the input |
| to the beginning of the output. */ |
| inend -= oplen; |
| memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend], |
| EXP_ELEM_TO_BYTES (oplen)); |
| outbeg += oplen; |
| |
| if (last_struct == inend) |
| result = outbeg - oplen; |
| |
| /* Find the lengths of the arg subexpressions. */ |
| arglens = (int *) alloca (args * sizeof (int)); |
| for (i = args - 1; i >= 0; i--) |
| { |
| oplen = length_of_subexp (inexpr, inend); |
| arglens[i] = oplen; |
| inend -= oplen; |
| } |
| |
| /* Now copy each subexpression, preserving the order of |
| the subexpressions, but prefixifying each one. |
| In this loop, inend starts at the beginning of |
| the expression this level is working on |
| and marches forward over the arguments. |
| outbeg does similarly in the output. */ |
| for (i = 0; i < args; i++) |
| { |
| int r; |
| |
| oplen = arglens[i]; |
| inend += oplen; |
| r = prefixify_subexp (inexpr, outexpr, inend, outbeg, last_struct); |
| if (r != -1) |
| { |
| /* Return immediately. We probably have only parsed a |
| partial expression, so we don't want to try to reverse |
| the other operands. */ |
| return r; |
| } |
| outbeg += oplen; |
| } |
| |
| return result; |
| } |
| |
| /* Read an expression from the string *STRINGPTR points to, |
| parse it, and return a pointer to a struct expression that we malloc. |
| Use block BLOCK as the lexical context for variable names; |
| if BLOCK is zero, use the block of the selected stack frame. |
| Meanwhile, advance *STRINGPTR to point after the expression, |
| at the first nonwhite character that is not part of the expression |
| (possibly a null character). |
| |
| If COMMA is nonzero, stop if a comma is reached. */ |
| |
| expression_up |
| parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block, |
| int comma, innermost_block_tracker *tracker) |
| { |
| return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL, |
| tracker, nullptr); |
| } |
| |
| /* As for parse_exp_1, except that if VOID_CONTEXT_P, then |
| no value is expected from the expression. |
| OUT_SUBEXP is set when attempting to complete a field name; in this |
| case it is set to the index of the subexpression on the |
| left-hand-side of the struct op. If not doing such completion, it |
| is left untouched. */ |
| |
| static expression_up |
| parse_exp_in_context (const char **stringptr, CORE_ADDR pc, |
| const struct block *block, |
| int comma, int void_context_p, int *out_subexp, |
| innermost_block_tracker *tracker, |
| expr_completion_state *cstate) |
| { |
| const struct language_defn *lang = NULL; |
| int subexp; |
| |
| if (*stringptr == 0 || **stringptr == 0) |
| error_no_arg (_("expression to compute")); |
| |
| const struct block *expression_context_block = block; |
| CORE_ADDR expression_context_pc = 0; |
| |
| innermost_block_tracker local_tracker; |
| if (tracker == nullptr) |
| tracker = &local_tracker; |
| |
| /* If no context specified, try using the current frame, if any. */ |
| if (!expression_context_block) |
| expression_context_block = get_selected_block (&expression_context_pc); |
| else if (pc == 0) |
| expression_context_pc = BLOCK_ENTRY_PC (expression_context_block); |
| else |
| expression_context_pc = pc; |
| |
| /* Fall back to using the current source static context, if any. */ |
| |
| if (!expression_context_block) |
| { |
| struct symtab_and_line cursal = get_current_source_symtab_and_line (); |
| if (cursal.symtab) |
| expression_context_block |
| = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab), |
| STATIC_BLOCK); |
| if (expression_context_block) |
| expression_context_pc = BLOCK_ENTRY_PC (expression_context_block); |
| } |
| |
| if (language_mode == language_mode_auto && block != NULL) |
| { |
| /* Find the language associated to the given context block. |
| Default to the current language if it can not be determined. |
| |
| Note that using the language corresponding to the current frame |
| can sometimes give unexpected results. For instance, this |
| routine is often called several times during the inferior |
| startup phase to re-parse breakpoint expressions after |
| a new shared library has been loaded. The language associated |
| to the current frame at this moment is not relevant for |
| the breakpoint. Using it would therefore be silly, so it seems |
| better to rely on the current language rather than relying on |
| the current frame language to parse the expression. That's why |
| we do the following language detection only if the context block |
| has been specifically provided. */ |
| struct symbol *func = block_linkage_function (block); |
| |
| if (func != NULL) |
| lang = language_def (func->language ()); |
| if (lang == NULL || lang->la_language == language_unknown) |
| lang = current_language; |
| } |
| else |
| lang = current_language; |
| |
| /* get_current_arch may reset CURRENT_LANGUAGE via select_frame. |
| While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol |
| and others called from *.y) ensure CURRENT_LANGUAGE gets restored |
| to the value matching SELECTED_FRAME as set by get_current_arch. */ |
| |
| parser_state ps (lang, get_current_arch (), expression_context_block, |
| expression_context_pc, comma, *stringptr, |
| cstate != nullptr, tracker); |
| |
| scoped_restore_current_language lang_saver; |
| set_language (lang->la_language); |
| |
| try |
| { |
| lang->parser (&ps); |
| } |
| catch (const gdb_exception &except) |
| { |
| /* If parsing for completion, allow this to succeed; but if no |
| expression elements have been written, then there's nothing |
| to do, so fail. */ |
| if (! ps.parse_completion || ps.expout_ptr == 0) |
| throw; |
| } |
| |
| /* We have to operate on an "expression *", due to la_post_parser, |
| which explains this funny-looking double release. */ |
| expression_up result = ps.release (); |
| |
| /* Convert expression from postfix form as generated by yacc |
| parser, to a prefix form. */ |
| |
| if (expressiondebug) |
| dump_raw_expression (result.get (), gdb_stdlog, |
| "before conversion to prefix form"); |
| |
| subexp = prefixify_expression (result.get (), |
| ps.m_completion_state.expout_last_struct); |
| if (out_subexp) |
| *out_subexp = subexp; |
| |
| lang->post_parser (&result, void_context_p, ps.parse_completion, tracker); |
| |
| if (expressiondebug) |
| dump_prefix_expression (result.get (), gdb_stdlog); |
| |
| if (cstate != nullptr) |
| *cstate = std::move (ps.m_completion_state); |
| *stringptr = ps.lexptr; |
| return result; |
| } |
| |
| /* Parse STRING as an expression, and complain if this fails |
| to use up all of the contents of STRING. */ |
| |
| expression_up |
| parse_expression (const char *string, innermost_block_tracker *tracker) |
| { |
| expression_up exp = parse_exp_1 (&string, 0, 0, 0, tracker); |
| if (*string) |
| error (_("Junk after end of expression.")); |
| return exp; |
| } |
| |
| /* Same as parse_expression, but using the given language (LANG) |
| to parse the expression. */ |
| |
| expression_up |
| parse_expression_with_language (const char *string, enum language lang) |
| { |
| gdb::optional<scoped_restore_current_language> lang_saver; |
| if (current_language->la_language != lang) |
| { |
| lang_saver.emplace (); |
| set_language (lang); |
| } |
| |
| return parse_expression (string); |
| } |
| |
| /* Parse STRING as an expression. If parsing ends in the middle of a |
| field reference, return the type of the left-hand-side of the |
| reference; furthermore, if the parsing ends in the field name, |
| return the field name in *NAME. If the parsing ends in the middle |
| of a field reference, but the reference is somehow invalid, throw |
| an exception. In all other cases, return NULL. */ |
| |
| struct type * |
| parse_expression_for_completion (const char *string, |
| gdb::unique_xmalloc_ptr<char> *name, |
| enum type_code *code) |
| { |
| expression_up exp; |
| struct value *val; |
| int subexp; |
| expr_completion_state cstate; |
| |
| try |
| { |
| exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp, |
| nullptr, &cstate); |
| } |
| catch (const gdb_exception_error &except) |
| { |
| /* Nothing, EXP remains NULL. */ |
| } |
| |
| if (exp == NULL) |
| return NULL; |
| |
| if (cstate.expout_tag_completion_type != TYPE_CODE_UNDEF) |
| { |
| *code = cstate.expout_tag_completion_type; |
| *name = std::move (cstate.expout_completion_name); |
| return NULL; |
| } |
| |
| if (cstate.expout_last_struct == -1) |
| return NULL; |
| |
| const char *fieldname = extract_field_op (exp.get (), &subexp); |
| if (fieldname == NULL) |
| { |
| name->reset (); |
| return NULL; |
| } |
| |
| name->reset (xstrdup (fieldname)); |
| /* This might throw an exception. If so, we want to let it |
| propagate. */ |
| val = evaluate_subexpression_type (exp.get (), subexp); |
| |
| return value_type (val); |
| } |
| |
| /* Parse floating point value P of length LEN. |
| Return false if invalid, true if valid. |
| The successfully parsed number is stored in DATA in |
| target format for floating-point type TYPE. |
| |
| NOTE: This accepts the floating point syntax that sscanf accepts. */ |
| |
| bool |
| parse_float (const char *p, int len, |
| const struct type *type, gdb_byte *data) |
| { |
| return target_float_from_string (data, type, std::string (p, len)); |
| } |
| |
| /* This function avoids direct calls to fprintf |
| in the parser generated debug code. */ |
| void |
| parser_fprintf (FILE *x, const char *y, ...) |
| { |
| va_list args; |
| |
| va_start (args, y); |
| if (x == stderr) |
| vfprintf_unfiltered (gdb_stderr, y, args); |
| else |
| { |
| fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n"); |
| vfprintf_unfiltered (gdb_stderr, y, args); |
| } |
| va_end (args); |
| } |
| |
| /* Implementation of the exp_descriptor method operator_check. */ |
| |
| int |
| operator_check_standard (struct expression *exp, int pos, |
| int (*objfile_func) (struct objfile *objfile, |
| void *data), |
| void *data) |
| { |
| const union exp_element *const elts = exp->elts; |
| struct type *type = NULL; |
| struct objfile *objfile = NULL; |
| |
| /* Extended operators should have been already handled by exp_descriptor |
| iterate method of its specific language. */ |
| gdb_assert (elts[pos].opcode < OP_EXTENDED0); |
| |
| /* Track the callers of write_exp_elt_type for this table. */ |
| |
| switch (elts[pos].opcode) |
| { |
| case BINOP_VAL: |
| case OP_COMPLEX: |
| case OP_FLOAT: |
| case OP_LONG: |
| case OP_SCOPE: |
| case OP_TYPE: |
| case UNOP_CAST: |
| case UNOP_MAX: |
| case UNOP_MEMVAL: |
| case UNOP_MIN: |
| type = elts[pos + 1].type; |
| break; |
| |
| case TYPE_INSTANCE: |
| { |
| LONGEST arg, nargs = elts[pos + 2].longconst; |
| |
| for (arg = 0; arg < nargs; arg++) |
| { |
| struct type *inst_type = elts[pos + 3 + arg].type; |
| struct objfile *inst_objfile = TYPE_OBJFILE (inst_type); |
| |
| if (inst_objfile && (*objfile_func) (inst_objfile, data)) |
| return 1; |
| } |
| } |
| break; |
| |
| case OP_VAR_VALUE: |
| { |
| const struct block *const block = elts[pos + 1].block; |
| const struct symbol *const symbol = elts[pos + 2].symbol; |
| |
| /* Check objfile where the variable itself is placed. |
| SYMBOL_OBJ_SECTION (symbol) may be NULL. */ |
| if ((*objfile_func) (symbol_objfile (symbol), data)) |
| return 1; |
| |
| /* Check objfile where is placed the code touching the variable. */ |
| objfile = block_objfile (block); |
| |
| type = SYMBOL_TYPE (symbol); |
| } |
| break; |
| case OP_VAR_MSYM_VALUE: |
| objfile = elts[pos + 1].objfile; |
| break; |
| } |
| |
| /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */ |
| |
| if (type && TYPE_OBJFILE (type) |
| && (*objfile_func) (TYPE_OBJFILE (type), data)) |
| return 1; |
| if (objfile && (*objfile_func) (objfile, data)) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* Call OBJFILE_FUNC for any objfile found being referenced by EXP. |
| OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get |
| passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC |
| returns non-zero value then (any other) non-zero value is immediately |
| returned to the caller. Otherwise zero is returned after iterating |
| through whole EXP. */ |
| |
| static int |
| exp_iterate (struct expression *exp, |
| int (*objfile_func) (struct objfile *objfile, void *data), |
| void *data) |
| { |
| int endpos; |
| |
| for (endpos = exp->nelts; endpos > 0; ) |
| { |
| int pos, args, oplen = 0; |
| |
| operator_length (exp, endpos, &oplen, &args); |
| gdb_assert (oplen > 0); |
| |
| pos = endpos - oplen; |
| if (exp->language_defn->la_exp_desc->operator_check (exp, pos, |
| objfile_func, data)) |
| return 1; |
| |
| endpos = pos; |
| } |
| |
| return 0; |
| } |
| |
| /* Helper for exp_uses_objfile. */ |
| |
| static int |
| exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp) |
| { |
| struct objfile *objfile = (struct objfile *) objfile_voidp; |
| |
| if (exp_objfile->separate_debug_objfile_backlink) |
| exp_objfile = exp_objfile->separate_debug_objfile_backlink; |
| |
| return exp_objfile == objfile; |
| } |
| |
| /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE |
| is unloaded), otherwise return 0. OBJFILE must not be a separate debug info |
| file. */ |
| |
| int |
| exp_uses_objfile (struct expression *exp, struct objfile *objfile) |
| { |
| gdb_assert (objfile->separate_debug_objfile_backlink == NULL); |
| |
| return exp_iterate (exp, exp_uses_objfile_iter, objfile); |
| } |
| |
| /* Reallocate the `expout' pointer inside PS so that it can accommodate |
| at least LENELT expression elements. This function does nothing if |
| there is enough room for the elements. */ |
| |
| static void |
| increase_expout_size (struct expr_builder *ps, size_t lenelt) |
| { |
| if ((ps->expout_ptr + lenelt) >= ps->expout_size) |
| { |
| ps->expout_size = std::max (ps->expout_size * 2, |
| ps->expout_ptr + lenelt + 10); |
| ps->expout.reset (XRESIZEVAR (expression, |
| ps->expout.release (), |
| (sizeof (struct expression) |
| + EXP_ELEM_TO_BYTES (ps->expout_size)))); |
| } |
| } |
| |
| void _initialize_parse (); |
| void |
| _initialize_parse () |
| { |
| add_setshow_zuinteger_cmd ("expression", class_maintenance, |
| &expressiondebug, |
| _("Set expression debugging."), |
| _("Show expression debugging."), |
| _("When non-zero, the internal representation " |
| "of expressions will be printed."), |
| NULL, |
| show_expressiondebug, |
| &setdebuglist, &showdebuglist); |
| add_setshow_boolean_cmd ("parser", class_maintenance, |
| &parser_debug, |
| _("Set parser debugging."), |
| _("Show parser debugging."), |
| _("When non-zero, expression parser " |
| "tracing will be enabled."), |
| NULL, |
| show_parserdebug, |
| &setdebuglist, &showdebuglist); |
| } |