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https://sourceware.org/git/binutils-gdb.git
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9497f5ac6b
- allowing true forward references (which will always assume the referenced symbols have at the point of use) through the new .eqv pseudo-op and the new == operator - disallowing changing .equiv-generated equates (so that the protection this provides is both forward and backward) - snapshotting equates when their value gets changed so that previous uses don't get affected by the new value. - allowing expressions in places where absolute expressions (or register names) are needed which were not completely resolvable at the point of their definition but which are fully resolvable at the point of use In addition it fixes PR/288.
181 lines
6.2 KiB
C
181 lines
6.2 KiB
C
/* expr.h -> header file for expr.c
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Copyright 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
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2002, 2003 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
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02110-1301, USA. */
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/*
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* By popular demand, we define a struct to represent an expression.
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* This will no doubt mutate as expressions become baroque.
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*
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* Currently, we support expressions like "foo OP bar + 42". In other
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* words we permit a (possibly undefined) symbol, a (possibly
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* undefined) symbol and the operation used to combine the symbols,
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* and an (absolute) augend. RMS says this is so we can have 1-pass
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* assembly for any compiler emissions, and a 'case' statement might
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* emit 'undefined1 - undefined2'.
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*
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* The type of an expression used to be stored as a segment. That got
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* confusing because it overloaded the concept of a segment. I added
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* an operator field, instead.
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*/
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/* This is the type of an expression. The operator types are also
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used while parsing an expression.
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NOTE: This enumeration must match the op_rank array in expr.c. */
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typedef enum {
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/* An illegal expression. */
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O_illegal,
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/* A nonexistent expression. */
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O_absent,
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/* X_add_number (a constant expression). */
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O_constant,
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/* X_add_symbol + X_add_number. */
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O_symbol,
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/* X_add_symbol + X_add_number - the base address of the image. */
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O_symbol_rva,
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/* A register (X_add_number is register number). */
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O_register,
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/* A big value. If X_add_number is negative or 0, the value is in
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generic_floating_point_number. Otherwise the value is in
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generic_bignum, and X_add_number is the number of LITTLENUMs in
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the value. */
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O_big,
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/* (- X_add_symbol) + X_add_number. */
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O_uminus,
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/* (~ X_add_symbol) + X_add_number. */
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O_bit_not,
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/* (! X_add_symbol) + X_add_number. */
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O_logical_not,
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/* (X_add_symbol * X_op_symbol) + X_add_number. */
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O_multiply,
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/* (X_add_symbol / X_op_symbol) + X_add_number. */
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O_divide,
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/* (X_add_symbol % X_op_symbol) + X_add_number. */
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O_modulus,
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/* (X_add_symbol << X_op_symbol) + X_add_number. */
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O_left_shift,
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/* (X_add_symbol >> X_op_symbol) + X_add_number. */
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O_right_shift,
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/* (X_add_symbol | X_op_symbol) + X_add_number. */
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O_bit_inclusive_or,
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/* (X_add_symbol |~ X_op_symbol) + X_add_number. */
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O_bit_or_not,
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/* (X_add_symbol ^ X_op_symbol) + X_add_number. */
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O_bit_exclusive_or,
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/* (X_add_symbol & X_op_symbol) + X_add_number. */
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O_bit_and,
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/* (X_add_symbol + X_op_symbol) + X_add_number. */
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O_add,
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/* (X_add_symbol - X_op_symbol) + X_add_number. */
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O_subtract,
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/* (X_add_symbol == X_op_symbol) + X_add_number. */
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O_eq,
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/* (X_add_symbol != X_op_symbol) + X_add_number. */
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O_ne,
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/* (X_add_symbol < X_op_symbol) + X_add_number. */
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O_lt,
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/* (X_add_symbol <= X_op_symbol) + X_add_number. */
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O_le,
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/* (X_add_symbol >= X_op_symbol) + X_add_number. */
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O_ge,
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/* (X_add_symbol > X_op_symbol) + X_add_number. */
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O_gt,
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/* (X_add_symbol && X_op_symbol) + X_add_number. */
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O_logical_and,
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/* (X_add_symbol || X_op_symbol) + X_add_number. */
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O_logical_or,
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/* X_op_symbol [ X_add_symbol ] */
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O_index,
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/* machine dependent operators */
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O_md1, O_md2, O_md3, O_md4, O_md5, O_md6, O_md7, O_md8,
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O_md9, O_md10, O_md11, O_md12, O_md13, O_md14, O_md15, O_md16,
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O_md17, O_md18, O_md19, O_md20, O_md21, O_md22, O_md23, O_md24,
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O_md25, O_md26, O_md27, O_md28, O_md29, O_md30, O_md31, O_md32,
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/* this must be the largest value */
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O_max
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} operatorT;
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typedef struct expressionS {
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/* The main symbol. */
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symbolS *X_add_symbol;
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/* The second symbol, if needed. */
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symbolS *X_op_symbol;
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/* A number to add. */
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offsetT X_add_number;
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/* The type of the expression. We can't assume that an arbitrary
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compiler can handle a bitfield of enum type. FIXME: We could
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check this using autoconf. */
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#ifdef __GNUC__
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operatorT X_op : 8;
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#else
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unsigned char X_op;
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#endif
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/* Non-zero if X_add_number should be regarded as unsigned. This is
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only valid for O_constant expressions. It is only used when an
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O_constant must be extended into a bignum (i.e., it is not used
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when performing arithmetic on these values).
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FIXME: This field is not set very reliably. */
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unsigned int X_unsigned : 1;
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/* 7 additional bits can be defined if needed. */
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/* Machine dependent field */
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unsigned short X_md;
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} expressionS;
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enum expr_mode
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{
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expr_evaluate,
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expr_normal,
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expr_defer
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};
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/* "result" should be type (expressionS *). */
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#define expression(result) expr (0, result, expr_normal)
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#define expression_and_evaluate(result) expr (0, result, expr_evaluate)
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#define deferred_expression(result) expr (0, result, expr_defer)
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/* If an expression is O_big, look here for its value. These common
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data may be clobbered whenever expr() is called. */
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/* Flonums returned here. Big enough to hold most precise flonum. */
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extern FLONUM_TYPE generic_floating_point_number;
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/* Bignums returned here. */
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extern LITTLENUM_TYPE generic_bignum[];
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/* Number of littlenums in above. */
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#define SIZE_OF_LARGE_NUMBER (20)
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typedef char operator_rankT;
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extern char get_symbol_end (void);
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extern void expr_begin (void);
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extern void expr_set_precedence (void);
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extern segT expr (int, expressionS *, enum expr_mode);
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extern unsigned int get_single_number (void);
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extern symbolS *make_expr_symbol (expressionS * expressionP);
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extern int expr_symbol_where (symbolS *, char **, unsigned int *);
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extern symbolS *expr_build_uconstant (offsetT);
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extern symbolS *expr_build_dot (void);
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int resolve_expression (expressionS *);
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