path: root/contrib/tools/yasm/libyasm/expr.h

/** 
 * \file libyasm/expr.h 
 * \brief YASM expression interface. 
 * 
 * \license 
 *  Copyright (C) 2001-2007  Michael Urman, Peter Johnson 
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 *  - Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 *  - Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND OTHER CONTRIBUTORS ``AS IS'' 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR OTHER CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE. 
 * \endlicense 
 */ 
#ifndef YASM_EXPR_H 
#define YASM_EXPR_H 
 
#ifndef YASM_LIB_DECL 
#define YASM_LIB_DECL 
#endif 
 
/** Type of an expression item.  Types are listed in canonical sorting order. 
 * See expr_order_terms(). 
 * Note #YASM_EXPR_PRECBC must be used carefully (in a-b pairs), as only 
 * symrecs can become the relative term in a #yasm_value. 
 */ 
typedef enum yasm_expr__type { 
    YASM_EXPR_NONE = 0,     /**< Nothing */ 
    YASM_EXPR_REG = 1<<0,   /**< Register */ 
    YASM_EXPR_INT = 1<<1,   /**< Integer value */ 
    YASM_EXPR_SUBST = 1<<2, /**< Substitution placeholder */ 
    YASM_EXPR_FLOAT = 1<<3, /**< Floating point value */ 
    YASM_EXPR_SYM = 1<<4,   /**< Symbol */ 
    YASM_EXPR_PRECBC = 1<<5,/**< Direct bytecode ref (rather than via sym) */ 
    YASM_EXPR_EXPR = 1<<6   /**< Subexpression */ 
} yasm_expr__type; 
 
/** Expression item. */ 
typedef struct yasm_expr__item { 
    yasm_expr__type type;   /**< Type */ 
 
    /** Expression item data.  Correct value depends on type. */ 
    union { 
        yasm_bytecode *precbc;  /**< Direct bytecode ref (YASM_EXPR_PRECBC) */ 
        yasm_symrec *sym;       /**< Symbol (YASM_EXPR_SYM) */ 
        yasm_expr *expn;        /**< Subexpression (YASM_EXPR_EXPR) */ 
        yasm_intnum *intn;      /**< Integer value (YASM_EXPR_INT) */ 
        yasm_floatnum *flt;     /**< Floating point value (YASM_EXPR_FLOAT) */ 
        uintptr_t reg;          /**< Register (YASM_EXPR_REG) */ 
        unsigned int subst;     /**< Subst placeholder (YASM_EXPR_SUBST) */ 
    } data; 
} yasm_expr__item; 
 
/** Expression. */ 
struct yasm_expr { 
    yasm_expr_op op;    /**< Operation. */ 
    unsigned long line; /**< Line number where expression was defined. */ 
    int numterms;       /**< Number of terms in the expression. */ 
 
    /** Terms of the expression.  Structure may be extended to include more 
     * terms, as some operations may allow more than two operand terms 
     * (ADD, MUL, OR, AND, XOR). 
     */ 
    yasm_expr__item terms[2]; 
}; 
 
/** Create a new expression e=a op b. 
 * \param op        operation 
 * \param a         expression item a 
 * \param b         expression item b (optional depending on op) 
 * \param line      virtual line (where expression defined) 
 * \return Newly allocated expression. 
 */ 
YASM_LIB_DECL 
/*@only@*/ yasm_expr *yasm_expr_create 
    (yasm_expr_op op, /*@only@*/ yasm_expr__item *a, 
     /*@only@*/ /*@null@*/ yasm_expr__item *b, unsigned long line); 
 
/** Create a new preceding-bytecode expression item. 
 * \param precbc    preceding bytecode 
 * \return Newly allocated expression item. 
 */ 
YASM_LIB_DECL 
/*@only@*/ yasm_expr__item *yasm_expr_precbc(/*@keep@*/ yasm_bytecode *precbc); 
 
/** Create a new symbol expression item. 
 * \param sym       symbol 
 * \return Newly allocated expression item. 
 */ 
YASM_LIB_DECL 
/*@only@*/ yasm_expr__item *yasm_expr_sym(/*@keep@*/ yasm_symrec *sym); 
 
/** Create a new expression expression item. 
 * \param e         expression 
 * \return Newly allocated expression item. 
 */ 
YASM_LIB_DECL 
/*@only@*/ yasm_expr__item *yasm_expr_expr(/*@keep@*/ yasm_expr *e); 
 
/** Create a new intnum expression item. 
 * \param intn      intnum 
 * \return Newly allocated expression item. 
 */ 
YASM_LIB_DECL 
/*@only@*/ yasm_expr__item *yasm_expr_int(/*@keep@*/ yasm_intnum *intn); 
 
/** Create a new floatnum expression item. 
 * \param flt       floatnum 
 * \return Newly allocated expression item. 
 */ 
YASM_LIB_DECL 
/*@only@*/ yasm_expr__item *yasm_expr_float(/*@keep@*/ yasm_floatnum *flt); 
 
/** Create a new register expression item. 
 * \param reg       register 
 * \return Newly allocated expression item. 
 */ 
YASM_LIB_DECL 
/*@only@*/ yasm_expr__item *yasm_expr_reg(uintptr_t reg); 
 
/** Create a new expression tree e=l op r. 
 * \param l     expression for left side of new expression 
 * \param o     operation 
 * \param r     expression for right side of new expression 
 * \param i     line index 
 * \return Newly allocated expression. 
 */ 
#define yasm_expr_create_tree(l,o,r,i) \ 
    yasm_expr_create ((o), yasm_expr_expr(l), yasm_expr_expr(r), i) 
 
/** Create a new expression branch e=op r. 
 * \param o     operation 
 * \param r     expression for right side of new expression 
 * \param i     line index 
 * \return Newly allocated expression. 
 */ 
#define yasm_expr_create_branch(o,r,i) \ 
    yasm_expr_create ((o), yasm_expr_expr(r), (yasm_expr__item *)NULL, i) 
 
/** Create a new expression identity e=r. 
 * \param r     expression for identity within new expression 
 * \param i     line index 
 * \return Newly allocated expression. 
 */ 
#define yasm_expr_create_ident(r,i) \ 
    yasm_expr_create (YASM_EXPR_IDENT, (r), (yasm_expr__item *)NULL, i) 
 
/** Duplicate an expression. 
 * \param e     expression 
 * \return Newly allocated expression identical to e. 
 */ 
yasm_expr *yasm_expr_copy(const yasm_expr *e); 
#ifndef YASM_DOXYGEN 
#define yasm_expr_copy(e)   yasm_expr__copy_except(e, -1) 
#endif 
 
/** Destroy (free allocated memory for) an expression. 
 * \param e     expression 
 */ 
YASM_LIB_DECL 
void yasm_expr_destroy(/*@only@*/ /*@null@*/ yasm_expr *e); 
 
/** Determine if an expression is a specified operation (at the top level). 
 * \param e             expression 
 * \param op            operator 
 * \return Nonzero if the expression was the specified operation at the top 
 *         level, zero otherwise. 
 */ 
YASM_LIB_DECL 
int yasm_expr_is_op(const yasm_expr *e, yasm_expr_op op); 
 
/** Extra transformation function for yasm_expr__level_tree(). 
 * \param e     expression being simplified 
 * \param d     data provided as expr_xform_extra_data to 
 *              yasm_expr__level_tree() 
 * \return Transformed e. 
 */ 
typedef /*@only@*/ yasm_expr * (*yasm_expr_xform_func) 
    (/*@returned@*/ /*@only@*/ yasm_expr *e, /*@null@*/ void *d); 
 
/** Level an entire expression tree. 
 * \internal 
 * \param e                 expression 
 * \param fold_const        enable constant folding if nonzero 
 * \param simplify_ident    simplify identities 
 * \param simplify_reg_mul  simplify REG*1 identities 
 * \param calc_bc_dist      nonzero if distances between bytecodes should be 
 *                          calculated, 0 if they should be left intact 
 * \param expr_xform_extra  extra transformation function 
 * \param expr_xform_extra_data data to pass to expr_xform_extra 
 * \return Leveled expression. 
 */ 
YASM_LIB_DECL 
/*@only@*/ /*@null@*/ yasm_expr *yasm_expr__level_tree 
    (/*@returned@*/ /*@only@*/ /*@null@*/ yasm_expr *e, int fold_const, 
     int simplify_ident, int simplify_reg_mul, int calc_bc_dist, 
     /*@null@*/ yasm_expr_xform_func expr_xform_extra, 
     /*@null@*/ void *expr_xform_extra_data); 
 
/** Simplify an expression as much as possible.  Eliminates extraneous 
 * branches and simplifies integer-only subexpressions.  Simplified version 
 * of yasm_expr__level_tree(). 
 * \param e     expression 
 * \param cbd   if distance between bytecodes should be calculated 
 * \return Simplified expression. 
 */ 
#define yasm_expr_simplify(e, cbd) \ 
    yasm_expr__level_tree(e, 1, 1, 1, cbd, NULL, NULL) 
 
/** Extract the segment portion of an expression containing SEG:OFF, leaving 
 * the offset. 
 * \param ep            expression (pointer to) 
 * \return NULL if unable to extract a segment (expr does not contain a 
 *         YASM_EXPR_SEGOFF operator), otherwise the segment expression. 
 *         The input expression is modified such that on return, it's the 
 *         offset expression. 
 */ 
YASM_LIB_DECL 
/*@only@*/ /*@null@*/ yasm_expr *yasm_expr_extract_deep_segoff(yasm_expr **ep); 
 
/** Extract the segment portion of a SEG:OFF expression, leaving the offset. 
 * \param ep            expression (pointer to) 
 * \return NULL if unable to extract a segment (YASM_EXPR_SEGOFF not the 
 *         top-level operator), otherwise the segment expression.  The input 
 *         expression is modified such that on return, it's the offset 
 *         expression. 
 */ 
YASM_LIB_DECL 
/*@only@*/ /*@null@*/ yasm_expr *yasm_expr_extract_segoff(yasm_expr **ep); 
 
/** Extract the right portion (y) of a x WRT y expression, leaving the left 
 * portion (x). 
 * \param ep            expression (pointer to) 
 * \return NULL if unable to extract (YASM_EXPR_WRT not the top-level 
 *         operator), otherwise the right side of the WRT expression.  The 
 *         input expression is modified such that on return, it's the left side 
 *         of the WRT expression. 
 */ 
YASM_LIB_DECL 
/*@only@*/ /*@null@*/ yasm_expr *yasm_expr_extract_wrt(yasm_expr **ep); 
 
/** Get the integer value of an expression if it's just an integer. 
 * \param ep            expression (pointer to) 
 * \param calc_bc_dist  nonzero if distances between bytecodes should be 
 *                      calculated, 0 if NULL should be returned in this case 
 * \return NULL if the expression is too complex (contains anything other than 
 *         integers, ie floats, non-valued labels, registers); otherwise the 
 *         intnum value of the expression. 
 */ 
YASM_LIB_DECL 
/*@dependent@*/ /*@null@*/ yasm_intnum *yasm_expr_get_intnum 
    (yasm_expr **ep, int calc_bc_dist); 
 
/** Get the symbol value of an expression if it's just a symbol. 
 * \param ep            expression (pointer to) 
 * \param simplify      if nonzero, simplify the expression first 
 * \return NULL if the expression is too complex; otherwise the symbol value of 
 *         the expression. 
 */ 
YASM_LIB_DECL 
/*@dependent@*/ /*@null@*/ const yasm_symrec *yasm_expr_get_symrec 
    (yasm_expr **ep, int simplify); 
 
/** Get the register value of an expression if it's just a register. 
 * \param ep            expression (pointer to) 
 * \param simplify      if nonzero, simplify the expression first 
 * \return NULL if the expression is too complex; otherwise the register value 
 *         of the expression. 
 */ 
YASM_LIB_DECL 
/*@dependent@*/ /*@null@*/ const uintptr_t *yasm_expr_get_reg 
    (yasm_expr **ep, int simplify); 
 
/** Print an expression.  For debugging purposes. 
 * \param e     expression 
 * \param f     file 
 */ 
YASM_LIB_DECL 
void yasm_expr_print(/*@null@*/ const yasm_expr *e, FILE *f); 
 
/** Return the size of an expression, if the user provided it 
 * \param e     expression 
 */ 
YASM_LIB_DECL 
unsigned int yasm_expr_size(const yasm_expr *e); 
 
/** Return the segment of an expression, if the user provided it 
 * \param e     expression 
 */ 
YASM_LIB_DECL 
const char *yasm_expr_segment(const yasm_expr *e); 
 
/** Traverse over expression tree in order (const version). 
 * Calls func for each leaf (non-operation). 
 * \param e     expression 
 * \param d     data passed to each call to func 
 * \param func  callback function 
 * \return Stops early (and returns 1) if func returns 1. 
 *         Otherwise returns 0. 
 */ 
YASM_LIB_DECL 
int yasm_expr__traverse_leaves_in_const 
    (const yasm_expr *e, /*@null@*/ void *d, 
     int (*func) (/*@null@*/ const yasm_expr__item *ei, /*@null@*/ void *d)); 
 
/** Traverse over expression tree in order. 
 * Calls func for each leaf (non-operation). 
 * \param e     expression 
 * \param d     data passed to each call to func 
 * \param func  callback function 
 * \return Stops early (and returns 1) if func returns 1. 
 *         Otherwise returns 0. 
 */ 
YASM_LIB_DECL 
int yasm_expr__traverse_leaves_in 
    (yasm_expr *e, /*@null@*/ void *d, 
     int (*func) (/*@null@*/ yasm_expr__item *ei, /*@null@*/ void *d)); 
 
/** Reorder terms of e into canonical order.  Only reorders if reordering 
 * doesn't change meaning of expression.  (eg, doesn't reorder SUB). 
 * Canonical order: REG, INT, FLOAT, SYM, EXPR. 
 * Multiple terms of a single type are kept in the same order as in 
 * the original expression. 
 * \param e     expression 
 * \note Only performs reordering on *one* level (no recursion). 
 */ 
YASM_LIB_DECL 
void yasm_expr__order_terms(yasm_expr *e); 
 
/** Copy entire expression EXCEPT for index "except" at *top level only*. 
 * \param e         expression 
 * \param except    term index not to copy; -1 to copy all terms 
 * \return Newly allocated copy of expression. 
 */ 
YASM_LIB_DECL 
yasm_expr *yasm_expr__copy_except(const yasm_expr *e, int except); 
 
/** Test if expression contains an item.  Searches recursively into 
 * subexpressions. 
 * \param e     expression 
 * \param t     type of item to look for 
 * \return Nonzero if expression contains an item of type t, zero if not. 
 */ 
YASM_LIB_DECL 
int yasm_expr__contains(const yasm_expr *e, yasm_expr__type t); 
 
/** Transform symrec-symrec terms in expression into #YASM_EXPR_SUBST items. 
 * Calls the callback function for each symrec-symrec term. 
 * \param ep            expression (pointer to) 
 * \param cbd           callback data passed to callback function 
 * \param callback      callback function: given subst index for bytecode 
 *                      pair, bytecode pair (bc2-bc1), and cbd (callback data) 
 * \return Number of transformations made. 
 */ 
YASM_LIB_DECL 
int yasm_expr__bc_dist_subst(yasm_expr **ep, void *cbd, 
                             void (*callback) (unsigned int subst, 
                                               yasm_bytecode *precbc, 
                                               yasm_bytecode *precbc2, 
                                               void *cbd)); 
 
/** Substitute items into expr YASM_EXPR_SUBST items (by index).  Items are 
 * copied, so caller is responsible for freeing array of items. 
 * \param e             expression 
 * \param num_items     number of items in items array 
 * \param items         items array 
 * \return 1 on error (index out of range). 
 */ 
YASM_LIB_DECL 
int yasm_expr__subst(yasm_expr *e, unsigned int num_items, 
                     const yasm_expr__item *items); 
 
#endif