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Diffstat (limited to 'gdb/expression.h')
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diff --git a/gdb/expression.h b/gdb/expression.h new file mode 100644 index 00000000000..310b2e297ac --- /dev/null +++ b/gdb/expression.h @@ -0,0 +1,382 @@ +/* Definitions for expressions stored in reversed prefix form, for GDB. + Copyright 1986, 1989, 1992, 1994 Free Software Foundation, Inc. + +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 2 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, write to the Free Software +Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +#if !defined (EXPRESSION_H) +#define EXPRESSION_H 1 + + +#include "symtab.h" /* Needed for "struct block" type. */ + + +/* Definitions for saved C expressions. */ + +/* An expression is represented as a vector of union exp_element's. + Each exp_element is an opcode, except that some opcodes cause + the following exp_element to be treated as a long or double constant + or as a variable. The opcodes are obeyed, using a stack for temporaries. + The value is left on the temporary stack at the end. */ + +/* When it is necessary to include a string, + it can occupy as many exp_elements as it needs. + We find the length of the string using strlen, + divide to find out how many exp_elements are used up, + and skip that many. Strings, like numbers, are indicated + by the preceding opcode. */ + +enum exp_opcode +{ + /* Used when it's necessary to pass an opcode which will be ignored, + or to catch uninitialized values. */ + OP_NULL, + +/* BINOP_... operate on two values computed by following subexpressions, + replacing them by one result value. They take no immediate arguments. */ + + BINOP_ADD, /* + */ + BINOP_SUB, /* - */ + BINOP_MUL, /* * */ + BINOP_DIV, /* / */ + BINOP_REM, /* % */ + BINOP_MOD, /* mod (Knuth 1.2.4) */ + BINOP_LSH, /* << */ + BINOP_RSH, /* >> */ + BINOP_LOGICAL_AND, /* && */ + BINOP_LOGICAL_OR, /* || */ + BINOP_BITWISE_AND, /* & */ + BINOP_BITWISE_IOR, /* | */ + BINOP_BITWISE_XOR, /* ^ */ + BINOP_EQUAL, /* == */ + BINOP_NOTEQUAL, /* != */ + BINOP_LESS, /* < */ + BINOP_GTR, /* > */ + BINOP_LEQ, /* <= */ + BINOP_GEQ, /* >= */ + BINOP_REPEAT, /* @ */ + BINOP_ASSIGN, /* = */ + BINOP_COMMA, /* , */ + BINOP_SUBSCRIPT, /* x[y] */ + BINOP_EXP, /* Exponentiation */ + + /* C++. */ + + BINOP_MIN, /* <? */ + BINOP_MAX, /* >? */ + BINOP_SCOPE, /* :: */ + + /* STRUCTOP_MEMBER is used for pointer-to-member constructs. + X . * Y translates into X STRUCTOP_MEMBER Y. */ + STRUCTOP_MEMBER, + + /* STRUCTOP_MPTR is used for pointer-to-member constructs + when X is a pointer instead of an aggregate. */ + STRUCTOP_MPTR, + + /* end of C++. */ + + /* For Modula-2 integer division DIV */ + BINOP_INTDIV, + + BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on. + The following exp_element is another opcode, + a BINOP_, saying how to modify. + Then comes another BINOP_ASSIGN_MODIFY, + making three exp_elements in total. */ + + /* Modula-2 standard (binary) procedures */ + BINOP_VAL, + BINOP_INCL, + BINOP_EXCL, + + /* Concatenate two operands, such as character strings or bitstrings. + If the first operand is a integer expression, then it means concatenate + the second operand with itself that many times. */ + BINOP_CONCAT, + + /* For Chill and Pascal. */ + BINOP_IN, /* Returns 1 iff ARG1 IN ARG2. */ + + /* This is the "colon operator" used various places in Chill. */ + BINOP_RANGE, + + /* This must be the highest BINOP_ value, for expprint.c. */ + BINOP_END, + + /* Operates on three values computed by following subexpressions. */ + TERNOP_COND, /* ?: */ + + /* A sub-string/sub-array. Chill syntax: OP1(OP2:OP3). + Return elements OP2 through OP3 of OP1. */ + TERNOP_SLICE, + + /* A sub-string/sub-array. Chill syntax: OP1(OP2 UP OP3). + Return OP3 elements of OP1, starting with element OP2. */ + TERNOP_SLICE_COUNT, + + /* Multidimensional subscript operator, such as Modula-2 x[a,b,...]. + The dimensionality is encoded in the operator, like the number of + function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>. + The value of the first following subexpression is subscripted + by each of the next following subexpressions, one per dimension. */ + MULTI_SUBSCRIPT, + + /* The OP_... series take immediate following arguments. + After the arguments come another OP_... (the same one) + so that the grouping can be recognized from the end. */ + + /* OP_LONG is followed by a type pointer in the next exp_element + and the long constant value in the following exp_element. + Then comes another OP_LONG. + Thus, the operation occupies four exp_elements. */ + OP_LONG, + + /* OP_DOUBLE is similar but takes a DOUBLEST constant instead of a long. */ + OP_DOUBLE, + + /* OP_VAR_VALUE takes one struct block * in the following element, + and one struct symbol * in the following exp_element, followed by + another OP_VAR_VALUE, making four exp_elements. If the block is + non-NULL, evaluate the symbol relative to the innermost frame + executing in that block; if the block is NULL use the selected frame. */ + OP_VAR_VALUE, + + /* OP_LAST is followed by an integer in the next exp_element. + The integer is zero for the last value printed, + or it is the absolute number of a history element. + With another OP_LAST at the end, this makes three exp_elements. */ + OP_LAST, + + /* OP_REGISTER is followed by an integer in the next exp_element. + This is the number of a register to fetch (as an int). + With another OP_REGISTER at the end, this makes three exp_elements. */ + OP_REGISTER, + + /* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element. + With another OP_INTERNALVAR at the end, this makes three exp_elements. */ + OP_INTERNALVAR, + + /* OP_FUNCALL is followed by an integer in the next exp_element. + The integer is the number of args to the function call. + That many plus one values from following subexpressions + are used, the first one being the function. + The integer is followed by a repeat of OP_FUNCALL, + making three exp_elements. */ + OP_FUNCALL, + + /* This is EXACTLY like OP_FUNCALL but is semantically different. + In F77, array subscript expressions, substring expressions + and function calls are all exactly the same syntactically. They may + only be dismabiguated at runtime. Thus this operator, which + indicates that we have found something of the form <name> ( <stuff> ) */ + OP_F77_UNDETERMINED_ARGLIST, + + /* The following OP is a special one, it introduces a F77 complex + literal. It is followed by exactly two args that are doubles. */ + OP_COMPLEX, + + /* OP_STRING represents a string constant. + Its format is the same as that of a STRUCTOP, but the string + data is just made into a string constant when the operation + is executed. */ + OP_STRING, + + /* OP_BITSTRING represents a packed bitstring constant. + Its format is the same as that of a STRUCTOP, but the bitstring + data is just made into a bitstring constant when the operation + is executed. */ + OP_BITSTRING, + + /* OP_ARRAY creates an array constant out of the following subexpressions. + It is followed by two exp_elements, the first containing an integer + that is the lower bound of the array and the second containing another + integer that is the upper bound of the array. The second integer is + followed by a repeat of OP_ARRAY, making four exp_elements total. + The bounds are used to compute the number of following subexpressions + to consume, as well as setting the bounds in the created array constant. + The type of the elements is taken from the type of the first subexp, + and they must all match. */ + OP_ARRAY, + + /* UNOP_CAST is followed by a type pointer in the next exp_element. + With another UNOP_CAST at the end, this makes three exp_elements. + It casts the value of the following subexpression. */ + UNOP_CAST, + + /* UNOP_MEMVAL is followed by a type pointer in the next exp_element + With another UNOP_MEMVAL at the end, this makes three exp_elements. + It casts the contents of the word addressed by the value of the + following subexpression. */ + UNOP_MEMVAL, + + /* UNOP_... operate on one value from a following subexpression + and replace it with a result. They take no immediate arguments. */ + + UNOP_NEG, /* Unary - */ + UNOP_LOGICAL_NOT, /* Unary ! */ + UNOP_COMPLEMENT, /* Unary ~ */ + UNOP_IND, /* Unary * */ + UNOP_ADDR, /* Unary & */ + UNOP_PREINCREMENT, /* ++ before an expression */ + UNOP_POSTINCREMENT, /* ++ after an expression */ + UNOP_PREDECREMENT, /* -- before an expression */ + UNOP_POSTDECREMENT, /* -- after an expression */ + UNOP_SIZEOF, /* Unary sizeof (followed by expression) */ + + UNOP_PLUS, /* Unary plus */ + + UNOP_CAP, /* Modula-2 standard (unary) procedures */ + UNOP_CHR, + UNOP_ORD, + UNOP_ABS, + UNOP_FLOAT, + UNOP_HIGH, + UNOP_MAX, + UNOP_MIN, + UNOP_ODD, + UNOP_TRUNC, + + /* Chill builtin functions. */ + UNOP_LOWER, UNOP_UPPER, UNOP_LENGTH, UNOP_CARD, UNOP_CHMAX, UNOP_CHMIN, + + OP_BOOL, /* Modula-2 builtin BOOLEAN type */ + OP_M2_STRING, /* Modula-2 string constants */ + + /* STRUCTOP_... operate on a value from a following subexpression + by extracting a structure component specified by a string + that appears in the following exp_elements (as many as needed). + STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->". + They differ only in the error message given in case the value is + not suitable or the structure component specified is not found. + + The length of the string follows the opcode, followed by + BYTES_TO_EXP_ELEM(length) elements containing the data of the + string, followed by the length again and the opcode again. */ + + STRUCTOP_STRUCT, + STRUCTOP_PTR, + + /* C++ */ + /* OP_THIS is just a placeholder for the class instance variable. + It just comes in a tight (OP_THIS, OP_THIS) pair. */ + OP_THIS, + + /* OP_SCOPE surrounds a type name and a field name. The type + name is encoded as one element, but the field name stays as + a string, which, of course, is variable length. */ + OP_SCOPE, + + /* Used to represent named structure field values in brace initializers + (or tuples as they are called in Chill). + The gcc C syntax is NAME:VALUE or .NAME=VALUE, the Chill syntax is + .NAME:VALUE. Multiple labels (as in the Chill syntax + .NAME1,.NAME2:VALUE) is represented as if it were + .NAME1:(.NAME2:VALUE) (though that is not valid Chill syntax). + + The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */ + OP_LABELED, + + /* OP_TYPE is for parsing types, and used with the "ptype" command + so we can look up types that are qualified by scope, either with + the GDB "::" operator, or the Modula-2 '.' operator. */ + OP_TYPE, + + /* An un-looked-up identifier. */ + OP_NAME, + + /* An unparsed expression. Used for Scheme (for now at least) */ + OP_EXPRSTRING +}; + +union exp_element +{ + enum exp_opcode opcode; + struct symbol *symbol; + LONGEST longconst; + DOUBLEST doubleconst; + /* Really sizeof (union exp_element) characters (or less for the last + element of a string). */ + char string; + struct type *type; + struct internalvar *internalvar; + struct block *block; +}; + +struct expression +{ + const struct language_defn *language_defn; /* language it was entered in */ + int nelts; + union exp_element elts[1]; +}; + +/* Macros for converting between number of expression elements and bytes + to store that many expression elements. */ + +#define EXP_ELEM_TO_BYTES(elements) \ + ((elements) * sizeof (union exp_element)) +#define BYTES_TO_EXP_ELEM(bytes) \ + (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element)) + +/* From parse.c */ + +extern struct expression *parse_expression PARAMS ((char *)); + +extern struct expression *parse_exp_1 PARAMS ((char **, struct block *, int)); + +/* The innermost context required by the stack and register variables + we've encountered so far. To use this, set it to NULL, then call + parse_<whatever>, then look at it. */ +extern struct block *innermost_block; + +/* From eval.c */ + +/* Values of NOSIDE argument to eval_subexp. */ + +enum noside +{ + EVAL_NORMAL, + EVAL_SKIP, /* Only effect is to increment pos. */ + EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or + call any functions. The value + returned will have the correct + type, and will have an + approximately correct lvalue + type (inaccuracy: anything that is + listed as being in a register in + the function in which it was + declared will be lval_register). */ +}; + +extern struct value* evaluate_subexp_standard +PARAMS ((struct type *, struct expression *, int*, enum noside)); + +/* From expprint.c */ + +extern void print_expression PARAMS ((struct expression *, GDB_FILE *)); + +extern char *op_string PARAMS ((enum exp_opcode)); + +#ifdef MAINTENANCE_CMDS +extern void dump_prefix_expression PARAMS ((struct expression *, + GDB_FILE *, + char *)); +extern void dump_postfix_expression PARAMS ((struct expression *, + GDB_FILE *, + char *)); +#endif /* MAINTENANCE_CMDS */ + +#endif /* !defined (EXPRESSION_H) */ |