URL
https://opencores.org/ocsvn/openrisc_2011-10-31/openrisc_2011-10-31/trunk
Subversion Repositories openrisc_2011-10-31
[/] [openrisc/] [trunk/] [gnu-src/] [gdb-7.2/] [gdb/] [parse.c] - Rev 445
Go to most recent revision | Compare with Previous | Blame | View Log
/* Parse expressions for GDB. Copyright (C) 1986, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2009, 2010 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 "gdb_string.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 "doublest.h" #include "gdb_assert.h" #include "block.h" #include "source.h" #include "objfiles.h" #include "exceptions.h" #include "user-regs.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 }; /* Global variables declared in parser-defs.h (and commented there). */ struct expression *expout; int expout_size; int expout_ptr; struct block *expression_context_block; CORE_ADDR expression_context_pc; struct block *innermost_block; int arglist_len; union type_stack_elt *type_stack; int type_stack_depth, type_stack_size; char *lexptr; char *prev_lexptr; int paren_depth; int comma_terminates; /* True if parsing an expression to find a field reference. This is only used by completion. */ int in_parse_field; /* The index of the last struct expression directly before a '.' or '->'. This is set when parsing and is only used when completing a field name. It is -1 if no dereference operation was found. */ static int expout_last_struct = -1; /* A temporary buffer for identifiers, so we can null-terminate them. We allocate this with xrealloc. parse_exp_1 used to allocate with alloca, using the size of the whole expression as a conservative estimate of the space needed. However, macro expansion can introduce names longer than the original expression; there's no practical way to know beforehand how large that might be. */ char *namecopy; size_t namecopy_size; static 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); } /* Non-zero if an expression parser should set yydebug. */ int 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 void free_funcalls (void *ignore); static int prefixify_expression (struct expression *); static int prefixify_subexp (struct expression *, struct expression *, int, int); static struct expression *parse_exp_in_context (char **, struct block *, int, int, int *); void _initialize_parse (void); /* Data structure for saving values of arglist_len for function calls whose arguments contain other function calls. */ struct funcall { struct funcall *next; int arglist_len; }; static struct funcall *funcall_chain; /* Begin counting arguments for a function call, saving the data about any containing call. */ void start_arglist (void) { struct funcall *new; new = (struct funcall *) xmalloc (sizeof (struct funcall)); new->next = funcall_chain; new->arglist_len = arglist_len; arglist_len = 0; funcall_chain = new; } /* Return the number of arguments in a function call just terminated, and restore the data for the containing function call. */ int end_arglist (void) { int val = arglist_len; struct funcall *call = funcall_chain; funcall_chain = call->next; arglist_len = call->arglist_len; xfree (call); return val; } /* Free everything in the funcall chain. Used when there is an error inside parsing. */ static void free_funcalls (void *ignore) { struct funcall *call, *next; for (call = funcall_chain; call; call = next) { next = call->next; xfree (call); } } /* 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 */ void write_exp_elt (union exp_element expelt) { if (expout_ptr >= expout_size) { expout_size *= 2; expout = (struct expression *) xrealloc ((char *) expout, sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size)); } expout->elts[expout_ptr++] = expelt; } void write_exp_elt_opcode (enum exp_opcode expelt) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.opcode = expelt; write_exp_elt (tmp); } void write_exp_elt_sym (struct symbol *expelt) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.symbol = expelt; write_exp_elt (tmp); } void write_exp_elt_block (struct block *b) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.block = b; write_exp_elt (tmp); } void write_exp_elt_objfile (struct objfile *objfile) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.objfile = objfile; write_exp_elt (tmp); } void write_exp_elt_longcst (LONGEST expelt) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.longconst = expelt; write_exp_elt (tmp); } void write_exp_elt_dblcst (DOUBLEST expelt) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.doubleconst = expelt; write_exp_elt (tmp); } void write_exp_elt_decfloatcst (gdb_byte expelt[16]) { union exp_element tmp; int index; for (index = 0; index < 16; index++) tmp.decfloatconst[index] = expelt[index]; write_exp_elt (tmp); } void write_exp_elt_type (struct type *expelt) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.type = expelt; write_exp_elt (tmp); } void write_exp_elt_intern (struct internalvar *expelt) { union exp_element tmp; memset (&tmp, 0, sizeof (union exp_element)); tmp.internalvar = expelt; write_exp_elt (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 stoken str) { int len = str.length; int 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); /* Ensure that we have enough available expression elements to store everything. */ if ((expout_ptr + lenelt) >= expout_size) { expout_size = max (expout_size * 2, expout_ptr + lenelt + 10); expout = (struct expression *) xrealloc ((char *) expout, (sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size))); } /* 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 ((LONGEST) len); strdata = (char *) &expout->elts[expout_ptr]; memcpy (strdata, str.ptr, len); *(strdata + len) = '\0'; expout_ptr += lenelt - 2; write_exp_elt_longcst ((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 (int type, struct stoken_vector *vec) { int i, n_slots, len; /* 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; if ((expout_ptr + n_slots) >= expout_size) { expout_size = max (expout_size * 2, expout_ptr + n_slots + 10); expout = (struct expression *) xrealloc ((char *) expout, (sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size))); } write_exp_elt_opcode (OP_STRING); write_exp_elt_longcst (len); write_exp_elt_longcst (type); for (i = 0; i < vec->len; ++i) { write_exp_elt_longcst (vec->tokens[i].length); memcpy (&expout->elts[expout_ptr], vec->tokens[i].ptr, vec->tokens[i].length); expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length); } write_exp_elt_longcst (len); write_exp_elt_opcode (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 stoken str) { int bits = str.length; /* length in bits */ int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT; int 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); /* Ensure that we have enough available expression elements to store everything. */ if ((expout_ptr + lenelt) >= expout_size) { expout_size = max (expout_size * 2, expout_ptr + lenelt + 10); expout = (struct expression *) xrealloc ((char *) expout, (sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size))); } /* 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 ((LONGEST) bits); strdata = (char *) &expout->elts[expout_ptr]; memcpy (strdata, str.ptr, len); expout_ptr += lenelt - 2; write_exp_elt_longcst ((LONGEST) bits); } /* Add the appropriate elements for a minimal symbol to the end of the expression. */ void write_exp_msymbol (struct minimal_symbol *msymbol) { struct objfile *objfile = msymbol_objfile (msymbol); struct gdbarch *gdbarch = get_objfile_arch (objfile); CORE_ADDR addr = SYMBOL_VALUE_ADDRESS (msymbol); struct obj_section *section = SYMBOL_OBJ_SECTION (msymbol); enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol); CORE_ADDR pc; /* The minimal symbol might point to a function descriptor; resolve it to the actual code address instead. */ pc = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, ¤t_target); if (pc != addr) { /* In this case, assume we have a code symbol instead of a data symbol. */ type = mst_text; section = NULL; addr = pc; } if (overlay_debugging) addr = symbol_overlayed_address (addr, section); write_exp_elt_opcode (OP_LONG); /* Let's make the type big enough to hold a 64-bit address. */ write_exp_elt_type (objfile_type (objfile)->builtin_core_addr); write_exp_elt_longcst ((LONGEST) addr); write_exp_elt_opcode (OP_LONG); if (section && section->the_bfd_section->flags & SEC_THREAD_LOCAL) { write_exp_elt_opcode (UNOP_MEMVAL_TLS); write_exp_elt_objfile (objfile); write_exp_elt_type (objfile_type (objfile)->nodebug_tls_symbol); write_exp_elt_opcode (UNOP_MEMVAL_TLS); return; } write_exp_elt_opcode (UNOP_MEMVAL); switch (type) { case mst_text: case mst_file_text: case mst_solib_trampoline: write_exp_elt_type (objfile_type (objfile)->nodebug_text_symbol); break; case mst_data: case mst_file_data: case mst_bss: case mst_file_bss: write_exp_elt_type (objfile_type (objfile)->nodebug_data_symbol); break; default: write_exp_elt_type (objfile_type (objfile)->nodebug_unknown_symbol); break; } write_exp_elt_opcode (UNOP_MEMVAL); } /* Mark the current index as the starting location of a structure expression. This is used when completing on field names. */ void mark_struct_expression (void) { expout_last_struct = expout_ptr; } /* 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 stoken str) { struct symbol *sym = NULL; struct minimal_symbol *msym = NULL; struct internalvar *isym = NULL; /* 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 (parse_gdbarch, str.ptr + 1, str.length - 1); if (i >= 0) goto handle_register; /* Any names starting with $ are probably debugger internal variables. */ isym = lookup_only_internalvar (copy_name (str) + 1); if (isym) { write_exp_elt_opcode (OP_INTERNALVAR); write_exp_elt_intern (isym); write_exp_elt_opcode (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_name (str), (struct block *) NULL, VAR_DOMAIN, (int *) NULL); if (sym) { write_exp_elt_opcode (OP_VAR_VALUE); write_exp_elt_block (block_found); /* set by lookup_symbol */ write_exp_elt_sym (sym); write_exp_elt_opcode (OP_VAR_VALUE); return; } msym = lookup_minimal_symbol (copy_name (str), NULL, NULL); if (msym) { write_exp_msymbol (msym); return; } /* Any other names are assumed to be debugger internal variables. */ write_exp_elt_opcode (OP_INTERNALVAR); write_exp_elt_intern (create_internalvar (copy_name (str) + 1)); write_exp_elt_opcode (OP_INTERNALVAR); return; handle_last: write_exp_elt_opcode (OP_LAST); write_exp_elt_longcst ((LONGEST) i); write_exp_elt_opcode (OP_LAST); return; handle_register: write_exp_elt_opcode (OP_REGISTER); str.length--; str.ptr++; write_exp_string (str); write_exp_elt_opcode (OP_REGISTER); return; } char * find_template_name_end (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. */ char * copy_name (struct stoken token) { /* Make sure there's enough space for the token. */ if (namecopy_size < token.length + 1) { namecopy_size = token.length + 1; namecopy = xrealloc (namecopy, token.length + 1); } memcpy (namecopy, token.ptr, token.length); namecopy[token.length] = 0; return namecopy; } /* Reverse an expression from suffix form (in which it is constructed) to prefix form (in which we can conveniently print or execute it). Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT is not -1 (i.e., we are trying to complete a field name), it will return the index of the subexpression which is the left-hand-side of the struct operation at EXPOUT_LAST_STRUCT. */ static int prefixify_expression (struct expression *expr) { 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); } /* Return the number of exp_elements in the postfix subexpression of EXPR whose operator is at index ENDPOS - 1 in EXPR. */ 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 f90_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_DOUBLE: case OP_DECFLOAT: case OP_VAR_VALUE: oplen = 4; break; case OP_TYPE: case OP_BOOL: case OP_LAST: case OP_INTERNALVAR: 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 = 4 + 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 BINOP_VAL: case UNOP_CAST: case UNOP_DYNAMIC_CAST: case UNOP_REINTERPRET_CAST: case UNOP_MEMVAL: oplen = 3; args = 1; break; case UNOP_MEMVAL_TLS: oplen = 4; 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: 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 OP_LABELED: 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_BITSTRING: oplen = longest_to_int (expr->elts[endpos - 2].longconst); oplen = (oplen + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT; oplen = 4 + BYTES_TO_EXP_ELEM (oplen); 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: case TERNOP_SLICE_COUNT: 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: case OP_OBJC_SELF: oplen = 2; break; case OP_F90_RANGE: oplen = 3; range_type = longest_to_int (expr->elts[endpos - 2].longconst); switch (range_type) { case LOW_BOUND_DEFAULT: case HIGH_BOUND_DEFAULT: args = 1; break; case BOTH_BOUND_DEFAULT: args = 0; break; case NONE_BOUND_DEFAULT: 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 EXPOUT_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 EXPOUT_LAST_STRUCT. */ static int prefixify_subexp (struct expression *inexpr, struct expression *outexpr, int inend, int outbeg) { 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 (expout_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); 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; } /* This page contains the two entry points to this file. */ /* 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. */ struct expression * parse_exp_1 (char **stringptr, struct block *block, int comma) { return parse_exp_in_context (stringptr, block, comma, 0, NULL); } /* 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 struct expression * parse_exp_in_context (char **stringptr, struct block *block, int comma, int void_context_p, int *out_subexp) { volatile struct gdb_exception except; struct cleanup *old_chain; const struct language_defn *lang = NULL; int subexp; lexptr = *stringptr; prev_lexptr = NULL; paren_depth = 0; type_stack_depth = 0; expout_last_struct = -1; comma_terminates = comma; if (lexptr == 0 || *lexptr == 0) error_no_arg (_("expression to compute")); old_chain = make_cleanup (free_funcalls, 0 /*ignore*/); funcall_chain = 0; expression_context_block = block; /* 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 expression_context_pc = BLOCK_START (expression_context_block); /* 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 (BLOCKVECTOR (cursal.symtab), STATIC_BLOCK); if (expression_context_block) expression_context_pc = BLOCK_START (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 (SYMBOL_LANGUAGE (func)); if (lang == NULL || lang->la_language == language_unknown) lang = current_language; } else lang = current_language; expout_size = 10; expout_ptr = 0; expout = (struct expression *) xmalloc (sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size)); expout->language_defn = lang; expout->gdbarch = get_current_arch (); TRY_CATCH (except, RETURN_MASK_ALL) { if (lang->la_parser ()) lang->la_error (NULL); } if (except.reason < 0) { if (! in_parse_field) { xfree (expout); throw_exception (except); } } discard_cleanups (old_chain); /* 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 = (struct expression *) xrealloc ((char *) expout, sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_ptr));; /* Convert expression from postfix form as generated by yacc parser, to a prefix form. */ if (expressiondebug) dump_raw_expression (expout, gdb_stdlog, "before conversion to prefix form"); subexp = prefixify_expression (expout); if (out_subexp) *out_subexp = subexp; lang->la_post_parser (&expout, void_context_p); if (expressiondebug) dump_prefix_expression (expout, gdb_stdlog); *stringptr = lexptr; return expout; } /* Parse STRING as an expression, and complain if this fails to use up all of the contents of STRING. */ struct expression * parse_expression (char *string) { struct expression *exp; exp = parse_exp_1 (&string, 0, 0); if (*string) error (_("Junk after end of expression.")); return exp; } /* 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. In all other cases, return NULL. Returned non-NULL *NAME must be freed by the caller. */ struct type * parse_field_expression (char *string, char **name) { struct expression *exp = NULL; struct value *val; int subexp; volatile struct gdb_exception except; TRY_CATCH (except, RETURN_MASK_ALL) { in_parse_field = 1; exp = parse_exp_in_context (&string, 0, 0, 0, &subexp); } in_parse_field = 0; if (except.reason < 0 || ! exp) return NULL; if (expout_last_struct == -1) { xfree (exp); return NULL; } *name = extract_field_op (exp, &subexp); if (!*name) { xfree (exp); return NULL; } /* (*NAME) is a part of the EXP memory block freed below. */ *name = xstrdup (*name); val = evaluate_subexpression_type (exp, subexp); xfree (exp); return value_type (val); } /* A post-parser that does nothing */ void null_post_parser (struct expression **exp, int void_context_p) { } /* Stuff for maintaining a stack of types. Currently just used by C, but probably useful for any language which declares its types "backwards". */ static void check_type_stack_depth (void) { if (type_stack_depth == type_stack_size) { type_stack_size *= 2; type_stack = (union type_stack_elt *) xrealloc ((char *) type_stack, type_stack_size * sizeof (*type_stack)); } } void push_type (enum type_pieces tp) { check_type_stack_depth (); type_stack[type_stack_depth++].piece = tp; } void push_type_int (int n) { check_type_stack_depth (); type_stack[type_stack_depth++].int_val = n; } void push_type_address_space (char *string) { push_type_int (address_space_name_to_int (parse_gdbarch, string)); } enum type_pieces pop_type (void) { if (type_stack_depth) return type_stack[--type_stack_depth].piece; return tp_end; } int pop_type_int (void) { if (type_stack_depth) return type_stack[--type_stack_depth].int_val; /* "Can't happen". */ return 0; } /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE as modified by all the stuff on the stack. */ struct type * follow_types (struct type *follow_type) { int done = 0; int make_const = 0; int make_volatile = 0; int make_addr_space = 0; int array_size; while (!done) switch (pop_type ()) { case tp_end: done = 1; if (make_const) follow_type = make_cv_type (make_const, TYPE_VOLATILE (follow_type), follow_type, 0); if (make_volatile) follow_type = make_cv_type (TYPE_CONST (follow_type), make_volatile, follow_type, 0); if (make_addr_space) follow_type = make_type_with_address_space (follow_type, make_addr_space); make_const = make_volatile = 0; make_addr_space = 0; break; case tp_const: make_const = 1; break; case tp_volatile: make_volatile = 1; break; case tp_space_identifier: make_addr_space = pop_type_int (); break; case tp_pointer: follow_type = lookup_pointer_type (follow_type); if (make_const) follow_type = make_cv_type (make_const, TYPE_VOLATILE (follow_type), follow_type, 0); if (make_volatile) follow_type = make_cv_type (TYPE_CONST (follow_type), make_volatile, follow_type, 0); if (make_addr_space) follow_type = make_type_with_address_space (follow_type, make_addr_space); make_const = make_volatile = 0; make_addr_space = 0; break; case tp_reference: follow_type = lookup_reference_type (follow_type); if (make_const) follow_type = make_cv_type (make_const, TYPE_VOLATILE (follow_type), follow_type, 0); if (make_volatile) follow_type = make_cv_type (TYPE_CONST (follow_type), make_volatile, follow_type, 0); if (make_addr_space) follow_type = make_type_with_address_space (follow_type, make_addr_space); make_const = make_volatile = 0; make_addr_space = 0; break; case tp_array: array_size = pop_type_int (); /* FIXME-type-allocation: need a way to free this type when we are done with it. */ follow_type = lookup_array_range_type (follow_type, 0, array_size >= 0 ? array_size - 1 : 0); if (array_size < 0) TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (follow_type) = 1; break; case tp_function: /* FIXME-type-allocation: need a way to free this type when we are done with it. */ follow_type = lookup_function_type (follow_type); break; } return follow_type; } /* 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_DECFLOAT: case OP_DOUBLE: case OP_LONG: case OP_SCOPE: case OP_TYPE: case UNOP_CAST: case UNOP_DYNAMIC_CAST: case UNOP_REINTERPRET_CAST: case UNOP_MAX: case UNOP_MEMVAL: case UNOP_MIN: type = elts[pos + 1].type; break; case TYPE_INSTANCE: { LONGEST arg, nargs = elts[pos + 1].longconst; for (arg = 0; arg < nargs; arg++) { struct type *type = elts[pos + 2 + arg].type; struct objfile *objfile = TYPE_OBJFILE (type); if (objfile && (*objfile_func) (objfile, data)) return 1; } } break; case UNOP_MEMVAL_TLS: objfile = elts[pos + 1].objfile; type = elts[pos + 2].type; 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_SYMTAB (symbol)->objfile, data)) return 1; /* Check objfile where is placed the code touching the variable. */ objfile = lookup_objfile_from_block (block); type = SYMBOL_TYPE (symbol); } 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 TYPE and OBJFILE found being referenced by EXP. The functions are never called with NULL OBJFILE. Functions get passed an arbitrary caller supplied DATA pointer. If any of the functions 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 = 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); } void _initialize_parse (void) { type_stack_size = 80; type_stack_depth = 0; type_stack = (union type_stack_elt *) xmalloc (type_stack_size * sizeof (*type_stack)); add_setshow_zinteger_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); }
Go to most recent revision | Compare with Previous | Blame | View Log