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authorStan Shebs <shebs@apple.com>1999-04-16 01:35:26 +0000
committerStan Shebs <shebs@apple.com>1999-04-16 01:35:26 +0000
commit14cd51f7793a9ce07bc435069f57269450141363 (patch)
tree280a2da48f771d61be5b451ddbacdf9ef8e9ad13 /gdb/expression.h
downloadgdb-14cd51f7793a9ce07bc435069f57269450141363.tar.gz
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+/* 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) */