[thirdparty/binutils-gdb.git] / gdb / expression.h

/* Definitions for expressions stored in reversed prefix form, for GDB.
   Copyright 1986, 1989, 1992 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#if !defined (EXPRESSION_H)
#define EXPRESSION_H 1

/* 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_LSH,		/* << */
  BINOP_RSH,		/* >> */
  BINOP_AND,		/* && */
  BINOP_OR,		/* || */
  BINOP_LOGAND,		/* & */
  BINOP_LOGIOR,		/* | */
  BINOP_LOGXOR,		/* ^ */
  BINOP_EQUAL,		/* == */
  BINOP_NOTEQUAL,	/* != */
  BINOP_LESS,		/* < */
  BINOP_GTR,		/* > */
  BINOP_LEQ,		/* <= */
  BINOP_GEQ,		/* >= */
  BINOP_REPEAT,		/* @ */
  BINOP_ASSIGN,		/* = */
  BINOP_COMMA,		/* , */
  BINOP_SUBSCRIPT,	/* x[y] */
  BINOP_MULTI_SUBSCRIPT, /* Modula-2 x[a,b,...] */
  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,

  /* This must be the highest BINOP_ value, for expprint.c.  */
  BINOP_END,

/* Operates on three values computed by following subexpressions.  */
  TERNOP_COND,		/* ?: */

/* 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 double constant instead of a long one.  */
  OP_DOUBLE,
/* OP_VAR_VALUE takes one struct symbol * in the following exp_element,
   followed by another OP_VAR_VALUE, making three exp_elements.  */
  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,
/* 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,

/* 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_ZEROP,		/* Unary ! */
  UNOP_LOGNOT,		/* 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,

  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.

   After the sub-expression and before the string is a (struct type*).
   This is normally NULL, but is used for the TYPE in a C++ qualified
   reference like EXP.TYPE::NAME.  (EXP.TYPE1::TYPE2::NAME does
   not work, unfortunately.)

   The length of the string follows in the next exp_element,
   (after the string), followed by another STRUCTOP_... code.  */
  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,

  /* 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
};

union exp_element
{
  enum exp_opcode opcode;
  struct symbol *symbol;
  LONGEST longconst;
  double doubleconst;
  char string;
  struct type *type;
  struct internalvar *internalvar;
};

struct expression
{
  const struct language_defn *language_defn;  /* language it was entered in */
  int nelts;
  union exp_element elts[1];
};

/* 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 expprint.c */

extern void
print_expression PARAMS ((struct expression *, FILE *));

extern char *
op_string PARAMS ((enum exp_opcode));

#endif	/* !defined (EXPRESSION_H) */
Commit	Line	Data
bd5635a1	1	/* Definitions for expressions stored in reversed prefix form, for GDB.
35fcebce	2	Copyright 1986, 1989, 1992 Free Software Foundation, Inc.
bd5635a1 RP	3
	4	This file is part of GDB.
	5
35fcebce	6	This program is free software; you can redistribute it and/or modify
bd5635a1	7	it under the terms of the GNU General Public License as published by
35fcebce PB	8	the Free Software Foundation; either version 2 of the License, or
35fcebce PB	9	(at your option) any later version.
bd5635a1	10
35fcebce	11	This program is distributed in the hope that it will be useful,
bd5635a1 RP	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
35fcebce PB	17	along with this program; if not, write to the Free Software
	18	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
	19
	20	#if !defined (EXPRESSION_H)
	21	#define EXPRESSION_H 1
bd5635a1 RP	22
	23	/* Definitions for saved C expressions. */
	24
	25	/* An expression is represented as a vector of union exp_element's.
	26	Each exp_element is an opcode, except that some opcodes cause
	27	the following exp_element to be treated as a long or double constant
	28	or as a variable. The opcodes are obeyed, using a stack for temporaries.
	29	The value is left on the temporary stack at the end. */
	30
	31	/* When it is necessary to include a string,
	32	it can occupy as many exp_elements as it needs.
	33	We find the length of the string using strlen,
	34	divide to find out how many exp_elements are used up,
	35	and skip that many. Strings, like numbers, are indicated
	36	by the preceding opcode. */
	37
	38	enum exp_opcode
	39	{
35fcebce PB	40	/* Used when it's necessary to pass an opcode which will be ignored,
	41	or to catch uninitialized values. */
	42	OP_NULL,
	43
bd5635a1 RP	44	/* BINOP_... operate on two values computed by following subexpressions,
	45	replacing them by one result value. They take no immediate arguments. */
	46	BINOP_ADD, /* + */
	47	BINOP_SUB, /* - */
	48	BINOP_MUL, /* * */
	49	BINOP_DIV, /* / */
	50	BINOP_REM, /* % */
	51	BINOP_LSH, /* << */
	52	BINOP_RSH, /* >> */
	53	BINOP_AND, /* && */
	54	BINOP_OR, /* \|\| */
	55	BINOP_LOGAND, /* & */
	56	BINOP_LOGIOR, /* \| */
	57	BINOP_LOGXOR, /* ^ */
	58	BINOP_EQUAL, /* == */
	59	BINOP_NOTEQUAL, /* != */
	60	BINOP_LESS, /* < */
	61	BINOP_GTR, /* > */
	62	BINOP_LEQ, /* <= */
	63	BINOP_GEQ, /* >= */
	64	BINOP_REPEAT, /* @ */
	65	BINOP_ASSIGN, /* = */
	66	BINOP_COMMA, /* , */
	67	BINOP_SUBSCRIPT, /* x[y] */
35fcebce	68	BINOP_MULTI_SUBSCRIPT, /* Modula-2 x[a,b,...] */
bd5635a1 RP	69	BINOP_EXP, /* Exponentiation */
	70
	71	/* C++. */
	72	BINOP_MIN, /* <? */
	73	BINOP_MAX, /* >? */
	74	BINOP_SCOPE, /* :: */
	75
	76	/* STRUCTOP_MEMBER is used for pointer-to-member constructs.
	77	X . * Y translates into X STRUCTOP_MEMBER Y. */
	78	STRUCTOP_MEMBER,
	79	/* STRUCTOP_MPTR is used for pointer-to-member constructs
	80	when X is a pointer instead of an aggregate. */
	81	STRUCTOP_MPTR,
	82	/* end of C++. */
	83
35fcebce PB	84	/* For Modula-2 integer division DIV */
35fcebce PB	85	BINOP_INTDIV,
bd5635a1 RP	86
	87	BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on.
	88	The following exp_element is another opcode,
	89	a BINOP_, saying how to modify.
	90	Then comes another BINOP_ASSIGN_MODIFY,
	91	making three exp_elements in total. */
	92
35fcebce PB	93	/* Modula-2 standard (binary) procedures*/
	94	BINOP_VAL,
	95	BINOP_INCL,
	96	BINOP_EXCL,
	97
	98	/* This must be the highest BINOP_ value, for expprint.c. */
	99	BINOP_END,
	100
bd5635a1 RP	101	/* Operates on three values computed by following subexpressions. */
	102	TERNOP_COND, /* ?: */
	103
	104	/* The OP_... series take immediate following arguments.
	105	After the arguments come another OP_... (the same one)
	106	so that the grouping can be recognized from the end. */
	107
	108	/* OP_LONG is followed by a type pointer in the next exp_element
	109	and the long constant value in the following exp_element.
	110	Then comes another OP_LONG.
	111	Thus, the operation occupies four exp_elements. */
	112
	113	OP_LONG,
	114	/* OP_DOUBLE is similar but takes a double constant instead of a long one. */
	115	OP_DOUBLE,
	116	/* OP_VAR_VALUE takes one struct symbol * in the following exp_element,
	117	followed by another OP_VAR_VALUE, making three exp_elements. */
	118	OP_VAR_VALUE,
	119	/* OP_LAST is followed by an integer in the next exp_element.
	120	The integer is zero for the last value printed,
	121	or it is the absolute number of a history element.
	122	With another OP_LAST at the end, this makes three exp_elements. */
	123	OP_LAST,
	124	/* OP_REGISTER is followed by an integer in the next exp_element.
	125	This is the number of a register to fetch (as an int).
	126	With another OP_REGISTER at the end, this makes three exp_elements. */
	127	OP_REGISTER,
	128	/* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element.
	129	With another OP_INTERNALVAR at the end, this makes three exp_elements. */
	130	OP_INTERNALVAR,
	131	/* OP_FUNCALL is followed by an integer in the next exp_element.
	132	The integer is the number of args to the function call.
	133	That many plus one values from following subexpressions
	134	are used, the first one being the function.
	135	The integer is followed by a repeat of OP_FUNCALL,
	136	making three exp_elements. */
	137	OP_FUNCALL,
	138	/* OP_STRING represents a string constant.
	139	Its format is the same as that of a STRUCTOP, but the string
	140	data is just made into a string constant when the operation
	141	is executed. */
	142	OP_STRING,
	143
	144	/* UNOP_CAST is followed by a type pointer in the next exp_element.
	145	With another UNOP_CAST at the end, this makes three exp_elements.
	146	It casts the value of the following subexpression. */
	147	UNOP_CAST,
	148	/* UNOP_MEMVAL is followed by a type pointer in the next exp_element
	149	With another UNOP_MEMVAL at the end, this makes three exp_elements.
	150	It casts the contents of the word addressed by the value of the
	151	following subexpression. */
	152	UNOP_MEMVAL,
	153	/* UNOP_... operate on one value from a following subexpression
	154	and replace it with a result. They take no immediate arguments. */
	155	UNOP_NEG, /* Unary - */
	156	UNOP_ZEROP, /* Unary ! */
	157	UNOP_LOGNOT, /* Unary ~ */
	158	UNOP_IND, /* Unary * */
	159	UNOP_ADDR, /* Unary & */
	160	UNOP_PREINCREMENT, /* ++ before an expression */
	161	UNOP_POSTINCREMENT, /* ++ after an expression */
	162	UNOP_PREDECREMENT, /* -- before an expression */
	163	UNOP_POSTDECREMENT, /* -- after an expression */
	164	UNOP_SIZEOF, /* Unary sizeof (followed by expression) */
165
35fcebce PB	166	UNOP_PLUS, /* Unary plus */
	167
	168	UNOP_CAP, /* Modula-2 standard (unary) procedures */
	169	UNOP_CHR,
	170	UNOP_ORD,
	171	UNOP_ABS,
	172	UNOP_FLOAT,
	173	UNOP_HIGH,
	174	UNOP_MAX,
	175	UNOP_MIN,
	176	UNOP_ODD,
	177	UNOP_TRUNC,
	178
	179	OP_BOOL, /* Modula-2 builtin BOOLEAN type */
	180	OP_M2_STRING, /* Modula-2 string constants */
	181
bd5635a1 RP	182	/* STRUCTOP_... operate on a value from a following subexpression
	183	by extracting a structure component specified by a string
	184	that appears in the following exp_elements (as many as needed).
	185	STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->".
	186	They differ only in the error message given in case the value is
	187	not suitable or the structure component specified is not found.
	188
35fcebce PB	189	After the sub-expression and before the string is a (struct type*).
	190	This is normally NULL, but is used for the TYPE in a C++ qualified
	191	reference like EXP.TYPE::NAME. (EXP.TYPE1::TYPE2::NAME does
	192	not work, unfortunately.)
	193
bd5635a1 RP	194	The length of the string follows in the next exp_element,
	195	(after the string), followed by another STRUCTOP_... code. */
	196	STRUCTOP_STRUCT,
	197	STRUCTOP_PTR,
	198
	199	/* C++ */
	200	/* OP_THIS is just a placeholder for the class instance variable.
	201	It just comes in a tight (OP_THIS, OP_THIS) pair. */
	202	OP_THIS,
	203
	204	/* OP_SCOPE surrounds a type name and a field name. The type
	205	name is encoded as one element, but the field name stays as
	206	a string, which, of course, is variable length. */
	207	OP_SCOPE,
	208
35fcebce PB	209	/* OP_TYPE is for parsing types, and used with the "ptype" command
	210	so we can look up types that are qualified by scope, either with
	211	the GDB "::" operator, or the Modula-2 '.' operator. */
	212	OP_TYPE
bd5635a1 RP	213	};
	214
	215	union exp_element
	216	{
	217	enum exp_opcode opcode;
	218	struct symbol *symbol;
	219	LONGEST longconst;
	220	double doubleconst;
	221	char string;
	222	struct type *type;
	223	struct internalvar *internalvar;
	224	};
	225
	226	struct expression
	227	{
35fcebce	228	const struct language_defn language_defn; / language it was entered in */
bd5635a1 RP	229	int nelts;
	230	union exp_element elts[1];
	231	};
	232
35fcebce PB	233	/* From parse.c */
	234
	235	extern struct expression *
	236	parse_expression PARAMS ((char *));
	237
	238	extern struct expression *
	239	parse_exp_1 PARAMS ((char *, struct block , int));
bd5635a1 RP	240
	241	/* The innermost context required by the stack and register variables
	242	we've encountered so far. To use this, set it to NULL, then call
35fcebce	243	parse_<whatever>, then look at it. */
bd5635a1 RP	244	extern struct block *innermost_block;
bd5635a1 RP	245
35fcebce PB	246	/* From expprint.c */
	247
	248	extern void
	249	print_expression PARAMS ((struct expression , FILE ));
	250
	251	extern char *
	252	op_string PARAMS ((enum exp_opcode));
	253
	254	#endif /* !defined (EXPRESSION_H) */