[deliverable/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

#ifdef __STDC__
struct block;	/* Forward declaration for prototypes */
#endif

/* 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,

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

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

/* 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 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_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,

  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 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));

/* To enable dumping of all parsed expressions in a human readable
   form, define DEBUG_EXPRESSIONS.  This is a compile time constant
   at the moment, since it's not clear that this feature is important
   enough to include by default. */

#ifdef DEBUG_EXPRESSIONS
extern void
dump_expression PARAMS ((struct expression *, FILE *, char *));
#define DUMP_EXPRESSION(exp,file,note) dump_expression ((exp), (file), (note))
#else
#define DUMP_EXPRESSION(exp,file,note)	/* Null expansion */
#endif	/* DEBUG_EXPRESSIONS */

#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	22
54bbbfb4 FF	23	#ifdef __STDC__
	24	struct block; /* Forward declaration for prototypes */
	25	#endif
	26
bd5635a1 RP	27	/* Definitions for saved C expressions. */
	28
	29	/* An expression is represented as a vector of union exp_element's.
	30	Each exp_element is an opcode, except that some opcodes cause
	31	the following exp_element to be treated as a long or double constant
	32	or as a variable. The opcodes are obeyed, using a stack for temporaries.
	33	The value is left on the temporary stack at the end. */
	34
	35	/* When it is necessary to include a string,
	36	it can occupy as many exp_elements as it needs.
	37	We find the length of the string using strlen,
	38	divide to find out how many exp_elements are used up,
	39	and skip that many. Strings, like numbers, are indicated
	40	by the preceding opcode. */
	41
	42	enum exp_opcode
	43	{
35fcebce PB	44	/* Used when it's necessary to pass an opcode which will be ignored,
	45	or to catch uninitialized values. */
	46	OP_NULL,
	47
bd5635a1 RP	48	/* BINOP_... operate on two values computed by following subexpressions,
	49	replacing them by one result value. They take no immediate arguments. */
	50	BINOP_ADD, /* + */
	51	BINOP_SUB, /* - */
	52	BINOP_MUL, /* * */
	53	BINOP_DIV, /* / */
	54	BINOP_REM, /* % */
76a0ffb4	55	BINOP_MOD, /* mod (Knuth 1.2.4) */
bd5635a1 RP	56	BINOP_LSH, /* << */
bd5635a1 RP	57	BINOP_RSH, /* >> */
54bbbfb4 FF	58	BINOP_LOGICAL_AND, /* && */
	59	BINOP_LOGICAL_OR, /* \|\| */
	60	BINOP_BITWISE_AND, /* & */
	61	BINOP_BITWISE_IOR, /* \| */
	62	BINOP_BITWISE_XOR, /* ^ */
bd5635a1 RP	63	BINOP_EQUAL, /* == */
	64	BINOP_NOTEQUAL, /* != */
	65	BINOP_LESS, /* < */
	66	BINOP_GTR, /* > */
	67	BINOP_LEQ, /* <= */
	68	BINOP_GEQ, /* >= */
	69	BINOP_REPEAT, /* @ */
	70	BINOP_ASSIGN, /* = */
	71	BINOP_COMMA, /* , */
	72	BINOP_SUBSCRIPT, /* x[y] */
	73	BINOP_EXP, /* Exponentiation */
	74
	75	/* C++. */
	76	BINOP_MIN, /* <? */
	77	BINOP_MAX, /* >? */
	78	BINOP_SCOPE, /* :: */
	79
	80	/* STRUCTOP_MEMBER is used for pointer-to-member constructs.
	81	X . * Y translates into X STRUCTOP_MEMBER Y. */
	82	STRUCTOP_MEMBER,
	83	/* STRUCTOP_MPTR is used for pointer-to-member constructs
	84	when X is a pointer instead of an aggregate. */
	85	STRUCTOP_MPTR,
	86	/* end of C++. */
	87
35fcebce PB	88	/* For Modula-2 integer division DIV */
35fcebce PB	89	BINOP_INTDIV,
bd5635a1 RP	90
	91	BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on.
	92	The following exp_element is another opcode,
	93	a BINOP_, saying how to modify.
	94	Then comes another BINOP_ASSIGN_MODIFY,
	95	making three exp_elements in total. */
	96
35fcebce PB	97	/* Modula-2 standard (binary) procedures*/
	98	BINOP_VAL,
	99	BINOP_INCL,
	100	BINOP_EXCL,
	101
	102	/* This must be the highest BINOP_ value, for expprint.c. */
	103	BINOP_END,
	104
bd5635a1 RP	105	/* Operates on three values computed by following subexpressions. */
	106	TERNOP_COND, /* ?: */
	107
54bbbfb4 FF	108	/* Multidimensional subscript operator, such as Modula-2 x[a,b,...].
	109	The dimensionality is encoded in the operator, like the number of
	110	function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>.
	111	The value of the first following subexpression is subscripted
	112	by each of the next following subexpressions, one per dimension. */
	113
	114	MULTI_SUBSCRIPT,
	115
bd5635a1 RP	116	/* The OP_... series take immediate following arguments.
	117	After the arguments come another OP_... (the same one)
	118	so that the grouping can be recognized from the end. */
	119
	120	/* OP_LONG is followed by a type pointer in the next exp_element
	121	and the long constant value in the following exp_element.
	122	Then comes another OP_LONG.
	123	Thus, the operation occupies four exp_elements. */
	124
	125	OP_LONG,
	126	/* OP_DOUBLE is similar but takes a double constant instead of a long one. */
	127	OP_DOUBLE,
	128	/* OP_VAR_VALUE takes one struct symbol * in the following exp_element,
	129	followed by another OP_VAR_VALUE, making three exp_elements. */
	130	OP_VAR_VALUE,
	131	/* OP_LAST is followed by an integer in the next exp_element.
	132	The integer is zero for the last value printed,
	133	or it is the absolute number of a history element.
	134	With another OP_LAST at the end, this makes three exp_elements. */
	135	OP_LAST,
	136	/* OP_REGISTER is followed by an integer in the next exp_element.
	137	This is the number of a register to fetch (as an int).
	138	With another OP_REGISTER at the end, this makes three exp_elements. */
	139	OP_REGISTER,
	140	/* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element.
	141	With another OP_INTERNALVAR at the end, this makes three exp_elements. */
	142	OP_INTERNALVAR,
	143	/* OP_FUNCALL is followed by an integer in the next exp_element.
	144	The integer is the number of args to the function call.
	145	That many plus one values from following subexpressions
	146	are used, the first one being the function.
	147	The integer is followed by a repeat of OP_FUNCALL,
	148	making three exp_elements. */
	149	OP_FUNCALL,
	150	/* OP_STRING represents a string constant.
	151	Its format is the same as that of a STRUCTOP, but the string
	152	data is just made into a string constant when the operation
	153	is executed. */
	154	OP_STRING,
	155
	156	/* UNOP_CAST is followed by a type pointer in the next exp_element.
	157	With another UNOP_CAST at the end, this makes three exp_elements.
	158	It casts the value of the following subexpression. */
	159	UNOP_CAST,
	160	/* UNOP_MEMVAL is followed by a type pointer in the next exp_element
	161	With another UNOP_MEMVAL at the end, this makes three exp_elements.
	162	It casts the contents of the word addressed by the value of the
	163	following subexpression. */
	164	UNOP_MEMVAL,
	165	/* UNOP_... operate on one value from a following subexpression
	166	and replace it with a result. They take no immediate arguments. */
	167	UNOP_NEG, /* Unary - */
54bbbfb4 FF	168	UNOP_LOGICAL_NOT, /* Unary ! */
54bbbfb4 FF	169	UNOP_COMPLEMENT, /* Unary ~ */
bd5635a1 RP	170	UNOP_IND, /* Unary * */
	171	UNOP_ADDR, /* Unary & */
	172	UNOP_PREINCREMENT, /* ++ before an expression */
	173	UNOP_POSTINCREMENT, /* ++ after an expression */
	174	UNOP_PREDECREMENT, /* -- before an expression */
	175	UNOP_POSTDECREMENT, /* -- after an expression */
	176	UNOP_SIZEOF, /* Unary sizeof (followed by expression) */
	177
35fcebce PB	178	UNOP_PLUS, /* Unary plus */
	179
	180	UNOP_CAP, /* Modula-2 standard (unary) procedures */
	181	UNOP_CHR,
	182	UNOP_ORD,
	183	UNOP_ABS,
	184	UNOP_FLOAT,
	185	UNOP_HIGH,
	186	UNOP_MAX,
	187	UNOP_MIN,
	188	UNOP_ODD,
	189	UNOP_TRUNC,
	190
	191	OP_BOOL, /* Modula-2 builtin BOOLEAN type */
	192	OP_M2_STRING, /* Modula-2 string constants */
	193
bd5635a1 RP	194	/* STRUCTOP_... operate on a value from a following subexpression
	195	by extracting a structure component specified by a string
	196	that appears in the following exp_elements (as many as needed).
	197	STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->".
	198	They differ only in the error message given in case the value is
	199	not suitable or the structure component specified is not found.
	200
	201	The length of the string follows in the next exp_element,
	202	(after the string), followed by another STRUCTOP_... code. */
	203	STRUCTOP_STRUCT,
	204	STRUCTOP_PTR,
	205
	206	/* C++ */
	207	/* OP_THIS is just a placeholder for the class instance variable.
	208	It just comes in a tight (OP_THIS, OP_THIS) pair. */
	209	OP_THIS,
	210
	211	/* OP_SCOPE surrounds a type name and a field name. The type
	212	name is encoded as one element, but the field name stays as
	213	a string, which, of course, is variable length. */
	214	OP_SCOPE,
	215
35fcebce PB	216	/* OP_TYPE is for parsing types, and used with the "ptype" command
	217	so we can look up types that are qualified by scope, either with
	218	the GDB "::" operator, or the Modula-2 '.' operator. */
	219	OP_TYPE
bd5635a1 RP	220	};
	221
	222	union exp_element
	223	{
	224	enum exp_opcode opcode;
	225	struct symbol *symbol;
	226	LONGEST longconst;
	227	double doubleconst;
	228	char string;
	229	struct type *type;
	230	struct internalvar *internalvar;
	231	};
	232
	233	struct expression
	234	{
35fcebce	235	const struct language_defn language_defn; / language it was entered in */
bd5635a1 RP	236	int nelts;
	237	union exp_element elts[1];
	238	};
	239
35fcebce PB	240	/* From parse.c */
	241
	242	extern struct expression *
	243	parse_expression PARAMS ((char *));
	244
	245	extern struct expression *
	246	parse_exp_1 PARAMS ((char *, struct block , int));
bd5635a1 RP	247
	248	/* The innermost context required by the stack and register variables
	249	we've encountered so far. To use this, set it to NULL, then call
35fcebce	250	parse_<whatever>, then look at it. */
bd5635a1 RP	251	extern struct block *innermost_block;
bd5635a1 RP	252
35fcebce PB	253	/* From expprint.c */
	254
	255	extern void
	256	print_expression PARAMS ((struct expression , FILE ));
	257
	258	extern char *
	259	op_string PARAMS ((enum exp_opcode));
	260
54bbbfb4 FF	261	/* To enable dumping of all parsed expressions in a human readable
	262	form, define DEBUG_EXPRESSIONS. This is a compile time constant
	263	at the moment, since it's not clear that this feature is important
	264	enough to include by default. */
	265
	266	#ifdef DEBUG_EXPRESSIONS
	267	extern void
	268	dump_expression PARAMS ((struct expression , FILE , char *));
	269	#define DUMP_EXPRESSION(exp,file,note) dump_expression ((exp), (file), (note))
	270	#else
	271	#define DUMP_EXPRESSION(exp,file,note) /* Null expansion */
	272	#endif /* DEBUG_EXPRESSIONS */
	273
35fcebce	274	#endif /* !defined (EXPRESSION_H) */