path: root/contrib/tools/yasm/libyasm/section.c

/* 
 * Section utility functions 
 * 
 *  Copyright (C) 2001-2007  Peter Johnson 
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 * 2. 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. 
 */ 
#include "util.h" 
 
#include <limits.h> 
 
#include "libyasm-stdint.h" 
#include "coretype.h" 
#include "hamt.h" 
#include "valparam.h" 
#include "assocdat.h" 
 
#include "linemap.h" 
#include "errwarn.h" 
#include "intnum.h" 
#include "expr.h" 
#include "value.h" 
#include "symrec.h" 
 
#include "bytecode.h" 
#include "arch.h" 
#include "section.h" 
 
#include "dbgfmt.h" 
#include "objfmt.h" 
 
#include "inttree.h" 
 
 
struct yasm_section { 
    /*@reldef@*/ STAILQ_ENTRY(yasm_section) link; 
 
    /*@dependent@*/ yasm_object *object;    /* Pointer to parent object */ 
 
    /*@owned@*/ char *name;     /* strdup()'ed name (given by user) */ 
 
    /* associated data; NULL if none */ 
    /*@null@*/ /*@only@*/ yasm__assoc_data *assoc_data; 
 
    unsigned long align;        /* Section alignment */ 
 
    unsigned long opt_flags;    /* storage for optimizer flags */ 
 
    int code;                   /* section contains code (instructions) */ 
    int res_only;               /* allow only resb family of bytecodes? */ 
    int def;                    /* "default" section, e.g. not specified by 
                                   using section directive */ 
 
    /* the bytecodes for the section's contents */ 
    /*@reldef@*/ STAILQ_HEAD(yasm_bytecodehead, yasm_bytecode) bcs; 
 
    /* the relocations for the section */ 
    /*@reldef@*/ STAILQ_HEAD(yasm_relochead, yasm_reloc) relocs; 
 
    void (*destroy_reloc) (/*@only@*/ void *reloc); 
}; 
 
static void yasm_section_destroy(/*@only@*/ yasm_section *sect); 
 
/* Wrapper around directive for HAMT insertion */ 
typedef struct yasm_directive_wrap { 
    const yasm_directive *directive; 
} yasm_directive_wrap; 
 
/* 
 * Standard "builtin" object directives. 
 */ 
 
static void 
dir_extern(yasm_object *object, yasm_valparamhead *valparams, 
           yasm_valparamhead *objext_valparams, unsigned long line) 
{ 
    yasm_valparam *vp = yasm_vps_first(valparams); 
    yasm_symrec *sym; 
    sym = yasm_symtab_declare(object->symtab, yasm_vp_id(vp), YASM_SYM_EXTERN, 
                              line); 
    if (objext_valparams) { 
        yasm_valparamhead *vps = yasm_vps_create(); 
        *vps = *objext_valparams;   /* structure copy */ 
        yasm_vps_initialize(objext_valparams);  /* don't double-free */ 
        yasm_symrec_set_objext_valparams(sym, vps); 
    } 
} 
 
static void 
dir_global(yasm_object *object, yasm_valparamhead *valparams, 
           yasm_valparamhead *objext_valparams, unsigned long line) 
{ 
    yasm_valparam *vp = yasm_vps_first(valparams); 
    yasm_symrec *sym; 
    sym = yasm_symtab_declare(object->symtab, yasm_vp_id(vp), YASM_SYM_GLOBAL, 
                              line); 
    if (objext_valparams) { 
        yasm_valparamhead *vps = yasm_vps_create(); 
        *vps = *objext_valparams;   /* structure copy */ 
        yasm_vps_initialize(objext_valparams);  /* don't double-free */ 
        yasm_symrec_set_objext_valparams(sym, vps); 
    } 
} 
 
static void 
dir_common(yasm_object *object, yasm_valparamhead *valparams, 
           yasm_valparamhead *objext_valparams, unsigned long line) 
{ 
    yasm_valparam *vp = yasm_vps_first(valparams); 
    yasm_valparam *vp2 = yasm_vps_next(vp); 
    yasm_expr *size = yasm_vp_expr(vp2, object->symtab, line); 
    yasm_symrec *sym; 
 
    if (!size) { 
        yasm_error_set(YASM_ERROR_SYNTAX, 
                       N_("no size specified in %s declaration"), "COMMON"); 
        return; 
    } 
    sym = yasm_symtab_declare(object->symtab, yasm_vp_id(vp), YASM_SYM_COMMON, 
                              line); 
    yasm_symrec_set_common_size(sym, size); 
    if (objext_valparams) { 
        yasm_valparamhead *vps = yasm_vps_create(); 
        *vps = *objext_valparams;   /* structure copy */ 
        yasm_vps_initialize(objext_valparams);  /* don't double-free */ 
        yasm_symrec_set_objext_valparams(sym, vps); 
    } 
} 
 
static void 
dir_section(yasm_object *object, yasm_valparamhead *valparams, 
            yasm_valparamhead *objext_valparams, unsigned long line) 
{ 
    yasm_section *new_section = 
        yasm_objfmt_section_switch(object, valparams, objext_valparams, line); 
    if (new_section) 
        object->cur_section = new_section; 
    else 
        yasm_error_set(YASM_ERROR_SYNTAX, 
                       N_("invalid argument to directive `%s'"), "SECTION"); 
} 
 
static const yasm_directive object_directives[] = { 
    { ".extern",        "gas",  dir_extern,     YASM_DIR_ID_REQUIRED }, 
    { ".global",        "gas",  dir_global,     YASM_DIR_ID_REQUIRED }, 
    { ".globl",         "gas",  dir_global,     YASM_DIR_ID_REQUIRED }, 
    { "extern",         "nasm", dir_extern,     YASM_DIR_ID_REQUIRED }, 
    { "global",         "nasm", dir_global,     YASM_DIR_ID_REQUIRED }, 
    { "common",         "nasm", dir_common,     YASM_DIR_ID_REQUIRED }, 
    { "section",        "nasm", dir_section,    YASM_DIR_ARG_REQUIRED }, 
    { "segment",        "nasm", dir_section,    YASM_DIR_ARG_REQUIRED }, 
    { NULL, NULL, NULL, 0 } 
}; 
 
static void 
directive_level2_delete(/*@only@*/ void *data) 
{ 
    yasm_xfree(data); 
} 
 
static void 
directive_level1_delete(/*@only@*/ void *data) 
{ 
    HAMT_destroy(data, directive_level2_delete); 
} 
 
static void 
directives_add(yasm_object *object, /*@null@*/ const yasm_directive *dir) 
{ 
    if (!dir) 
        return; 
 
    while (dir->name) { 
        HAMT *level2 = HAMT_search(object->directives, dir->parser); 
        int replace; 
        yasm_directive_wrap *wrap = yasm_xmalloc(sizeof(yasm_directive_wrap)); 
 
        if (!level2) { 
            replace = 0; 
            level2 = HAMT_insert(object->directives, dir->parser, 
                                 HAMT_create(1, yasm_internal_error_), 
                                 &replace, directive_level1_delete); 
        } 
        replace = 0; 
        wrap->directive = dir; 
        HAMT_insert(level2, dir->name, wrap, &replace, 
                    directive_level2_delete); 
        dir++; 
    } 
} 
 
/*@-compdestroy@*/ 
yasm_object * 
yasm_object_create(const char *src_filename, const char *obj_filename, 
                   /*@kept@*/ yasm_arch *arch, 
                   const yasm_objfmt_module *objfmt_module, 
                   const yasm_dbgfmt_module *dbgfmt_module) 
{ 
    yasm_object *object = yasm_xmalloc(sizeof(yasm_object)); 
    int matched, i; 
 
    object->src_filename = yasm__xstrdup(src_filename); 
    object->deb_filename = NULL;
    object->obj_filename = yasm__xstrdup(obj_filename); 
 
    /* No prefix/suffix */ 
    object->global_prefix = yasm__xstrdup(""); 
    object->global_suffix = yasm__xstrdup(""); 
 
    /* Create empty symbol table */ 
    object->symtab = yasm_symtab_create(); 
 
    /* Initialize sections linked list */ 
    STAILQ_INIT(&object->sections); 
 
    /* Create directives HAMT */ 
    object->directives = HAMT_create(1, yasm_internal_error_); 
 
    /* Initialize the target architecture */ 
    object->arch = arch; 
 
    /* Initialize things to NULL in case of error */ 
    object->dbgfmt = NULL; 
 
    /* Initialize the object format */ 
    object->objfmt = yasm_objfmt_create(objfmt_module, object); 
    if (!object->objfmt) { 
        yasm_error_set(YASM_ERROR_GENERAL, 
            N_("object format `%s' does not support architecture `%s' machine `%s'"), 
            objfmt_module->keyword, ((yasm_arch_base *)arch)->module->keyword, 
            yasm_arch_get_machine(arch)); 
        goto error; 
    } 
 
    /* Get a fresh copy of objfmt_module as it may have changed. */ 
    objfmt_module = ((yasm_objfmt_base *)object->objfmt)->module; 
 
    /* Add an initial "default" section to object */ 
    object->cur_section = yasm_objfmt_add_default_section(object); 
 
    /* Check to see if the requested debug format is in the allowed list 
     * for the active object format. 
     */ 
    matched = 0; 
    for (i=0; objfmt_module->dbgfmt_keywords[i]; i++) { 
        if (yasm__strcasecmp(objfmt_module->dbgfmt_keywords[i], 
                             dbgfmt_module->keyword) == 0) { 
            matched = 1; 
            break; 
        } 
    } 
 
    if (!matched) { 
        yasm_error_set(YASM_ERROR_GENERAL, 
            N_("`%s' is not a valid debug format for object format `%s'"), 
            dbgfmt_module->keyword, objfmt_module->keyword); 
        goto error; 
    } 
 
    /* Initialize the debug format */ 
    object->dbgfmt = yasm_dbgfmt_create(dbgfmt_module, object); 
    if (!object->dbgfmt) { 
        yasm_error_set(YASM_ERROR_GENERAL, 
            N_("debug format `%s' does not work with object format `%s'"), 
            dbgfmt_module->keyword, objfmt_module->keyword); 
        goto error; 
    } 
 
    /* Add directives to HAMT.  Note ordering here determines priority. */ 
    directives_add(object, 
                   ((yasm_objfmt_base *)object->objfmt)->module->directives); 
    directives_add(object, 
                   ((yasm_dbgfmt_base *)object->dbgfmt)->module->directives); 
    directives_add(object, 
                   ((yasm_arch_base *)object->arch)->module->directives); 
    directives_add(object, object_directives); 
 
    return object; 
 
error: 
    yasm_object_destroy(object); 
    return NULL; 
} 
/*@=compdestroy@*/ 
 
/*@-onlytrans@*/ 
yasm_section * 
yasm_object_get_general(yasm_object *object, const char *name, 
                        unsigned long align, int code, int res_only, 
                        int *isnew, unsigned long line) 
{ 
    yasm_section *s; 
    yasm_bytecode *bc; 
 
    /* Search through current sections to see if we already have one with 
     * that name. 
     */ 
    STAILQ_FOREACH(s, &object->sections, link) { 
        if (strcmp(s->name, name) == 0) { 
            *isnew = 0; 
            return s; 
        } 
    } 
 
    /* No: we have to allocate and create a new one. */ 
 
    /* Okay, the name is valid; now allocate and initialize */ 
    s = yasm_xcalloc(1, sizeof(yasm_section)); 
    STAILQ_INSERT_TAIL(&object->sections, s, link); 
 
    s->object = object; 
    s->name = yasm__xstrdup(name); 
    s->assoc_data = NULL; 
    s->align = align; 
 
    /* Initialize bytecodes with one empty bytecode (acts as "prior" for first 
     * real bytecode in section. 
     */ 
    STAILQ_INIT(&s->bcs); 
    bc = yasm_bc_create_common(NULL, NULL, 0); 
    bc->section = s; 
    bc->offset = 0; 
    STAILQ_INSERT_TAIL(&s->bcs, bc, link); 
 
    /* Initialize relocs */ 
    STAILQ_INIT(&s->relocs); 
    s->destroy_reloc = NULL; 
 
    s->code = code; 
    s->res_only = res_only; 
    s->def = 0; 
 
    /* Initialize object format specific data */ 
    yasm_objfmt_init_new_section(s, line); 
 
    *isnew = 1; 
    return s; 
} 
/*@=onlytrans@*/ 
 
int 
yasm_object_directive(yasm_object *object, const char *name, 
                      const char *parser, yasm_valparamhead *valparams, 
                      yasm_valparamhead *objext_valparams, 
                      unsigned long line) 
{ 
    HAMT *level2; 
    yasm_directive_wrap *wrap; 
 
    level2 = HAMT_search(object->directives, parser); 
    if (!level2) 
        return 1; 
 
    wrap = HAMT_search(level2, name); 
    if (!wrap) 
        return 1; 
 
    yasm_call_directive(wrap->directive, object, valparams, objext_valparams, 
                        line); 
    return 0; 
} 
 
void 
yasm_object_set_source_fn(yasm_object *object, const char *src_filename) 
{ 
    yasm_xfree(object->src_filename); 
    object->src_filename = yasm__xstrdup(src_filename); 
    yasm_xfree(object->deb_filename);
    object->deb_filename = NULL;
} 
 
void 
yasm_object_set_global_prefix(yasm_object *object, const char *prefix) 
{ 
    yasm_xfree(object->global_prefix); 
    object->global_prefix = yasm__xstrdup(prefix); 
} 
 
void 
yasm_object_set_global_suffix(yasm_object *object, const char *suffix) 
{ 
    yasm_xfree(object->global_suffix); 
    object->global_suffix = yasm__xstrdup(suffix); 
} 
 
int 
yasm_section_is_code(yasm_section *sect) 
{ 
    return sect->code; 
} 
 
unsigned long 
yasm_section_get_opt_flags(const yasm_section *sect) 
{ 
    return sect->opt_flags; 
} 
 
void 
yasm_section_set_opt_flags(yasm_section *sect, unsigned long opt_flags) 
{ 
    sect->opt_flags = opt_flags; 
} 
 
int 
yasm_section_is_default(const yasm_section *sect) 
{ 
    return sect->def; 
} 
 
void 
yasm_section_set_default(yasm_section *sect, int def) 
{ 
    sect->def = def; 
} 
 
yasm_object * 
yasm_section_get_object(const yasm_section *sect) 
{ 
    return sect->object; 
} 
 
void * 
yasm_section_get_data(yasm_section *sect, 
                      const yasm_assoc_data_callback *callback) 
{ 
    return yasm__assoc_data_get(sect->assoc_data, callback); 
} 
 
void 
yasm_section_add_data(yasm_section *sect, 
                      const yasm_assoc_data_callback *callback, void *data) 
{ 
    sect->assoc_data = yasm__assoc_data_add(sect->assoc_data, callback, data); 
} 
 
void 
yasm_object_destroy(yasm_object *object) 
{ 
    yasm_section *cur, *next; 
 
    /* Delete object format, debug format, and arch.  This can be called 
     * due to an error in yasm_object_create(), so look out for NULLs. 
     */ 
    if (object->objfmt) 
        yasm_objfmt_destroy(object->objfmt); 
    if (object->dbgfmt) 
        yasm_dbgfmt_destroy(object->dbgfmt); 
 
    /* Delete sections */ 
    cur = STAILQ_FIRST(&object->sections); 
    while (cur) { 
        next = STAILQ_NEXT(cur, link); 
        yasm_section_destroy(cur); 
        cur = next; 
    } 
 
    /* Delete directives HAMT */ 
    HAMT_destroy(object->directives, directive_level1_delete); 
 
    /* Delete prefix/suffix */ 
    yasm_xfree(object->global_prefix); 
    yasm_xfree(object->global_suffix); 
 
    /* Delete associated filenames */ 
    yasm_xfree(object->src_filename); 
    yasm_xfree(object->deb_filename);
    yasm_xfree(object->obj_filename); 
 
    /* Delete symbol table */ 
    yasm_symtab_destroy(object->symtab); 
 
    /* Delete architecture */ 
    if (object->arch) 
        yasm_arch_destroy(object->arch); 
 
    yasm_xfree(object); 
} 
 
void 
yasm_object_print(const yasm_object *object, FILE *f, int indent_level) 
{ 
    yasm_section *cur; 
 
    /* Print symbol table */ 
    fprintf(f, "%*sSymbol Table:\n", indent_level, ""); 
    yasm_symtab_print(object->symtab, f, indent_level+1); 
 
    /* Print sections and bytecodes */ 
    STAILQ_FOREACH(cur, &object->sections, link) { 
        fprintf(f, "%*sSection:\n", indent_level, ""); 
        yasm_section_print(cur, f, indent_level+1, 1); 
    } 
} 
 
void 
yasm_object_finalize(yasm_object *object, yasm_errwarns *errwarns) 
{ 
    yasm_section *sect; 
 
    /* Iterate through sections */ 
    STAILQ_FOREACH(sect, &object->sections, link) { 
        yasm_bytecode *cur = STAILQ_FIRST(&sect->bcs); 
        yasm_bytecode *prev; 
 
        /* Skip our locally created empty bytecode first. */ 
        prev = cur; 
        cur = STAILQ_NEXT(cur, link); 
 
        /* Iterate through the remainder, if any. */ 
        while (cur) { 
            /* Finalize */ 
            yasm_bc_finalize(cur, prev); 
            yasm_errwarn_propagate(errwarns, cur->line); 
            prev = cur; 
            cur = STAILQ_NEXT(cur, link); 
        } 
    } 
} 
 
int 
yasm_object_sections_traverse(yasm_object *object, /*@null@*/ void *d, 
                              int (*func) (yasm_section *sect, 
                                           /*@null@*/ void *d)) 
{ 
    yasm_section *cur; 
 
    STAILQ_FOREACH(cur, &object->sections, link) { 
        int retval = func(cur, d); 
        if (retval != 0) 
            return retval; 
    } 
    return 0; 
} 
 
/*@-onlytrans@*/ 
yasm_section * 
yasm_object_find_general(yasm_object *object, const char *name) 
{ 
    yasm_section *cur; 
 
    STAILQ_FOREACH(cur, &object->sections, link) { 
        if (strcmp(cur->name, name) == 0) 
            return cur; 
    } 
    return NULL; 
} 
/*@=onlytrans@*/ 
 
void 
yasm_section_add_reloc(yasm_section *sect, yasm_reloc *reloc, 
                       void (*destroy_func) (/*@only@*/ void *reloc)) 
{ 
    STAILQ_INSERT_TAIL(&sect->relocs, reloc, link); 
    if (!destroy_func) 
        yasm_internal_error(N_("NULL destroy function given to add_reloc")); 
    else if (sect->destroy_reloc && destroy_func != sect->destroy_reloc) 
        yasm_internal_error(N_("different destroy function given to add_reloc")); 
    sect->destroy_reloc = destroy_func; 
} 
 
/*@null@*/ yasm_reloc * 
yasm_section_relocs_first(yasm_section *sect) 
{ 
    return STAILQ_FIRST(&sect->relocs); 
} 
 
#undef yasm_section_reloc_next 
/*@null@*/ yasm_reloc * 
yasm_section_reloc_next(yasm_reloc *reloc) 
{ 
    return STAILQ_NEXT(reloc, link); 
} 
 
void 
yasm_reloc_get(yasm_reloc *reloc, yasm_intnum **addrp, yasm_symrec **symp) 
{ 
    *addrp = reloc->addr; 
    *symp = reloc->sym; 
} 
 
 
yasm_bytecode * 
yasm_section_bcs_first(yasm_section *sect) 
{ 
    return STAILQ_FIRST(&sect->bcs); 
} 
 
yasm_bytecode * 
yasm_section_bcs_last(yasm_section *sect) 
{ 
    return STAILQ_LAST(&sect->bcs, yasm_bytecode, link); 
} 
 
yasm_bytecode * 
yasm_section_bcs_append(yasm_section *sect, yasm_bytecode *bc) 
{ 
    if (bc) { 
        if (bc->callback) { 
            bc->section = sect;     /* record parent section */ 
            STAILQ_INSERT_TAIL(&sect->bcs, bc, link); 
            return bc; 
        } else 
            yasm_xfree(bc); 
    } 
    return (yasm_bytecode *)NULL; 
} 
 
int 
yasm_section_bcs_traverse(yasm_section *sect, 
                          /*@null@*/ yasm_errwarns *errwarns, 
                          /*@null@*/ void *d, 
                          int (*func) (yasm_bytecode *bc, /*@null@*/ void *d)) 
{ 
    yasm_bytecode *cur = STAILQ_FIRST(&sect->bcs); 
 
    /* Skip our locally created empty bytecode first. */ 
    cur = STAILQ_NEXT(cur, link); 
 
    /* Iterate through the remainder, if any. */ 
    while (cur) { 
        int retval = func(cur, d); 
        if (errwarns) 
            yasm_errwarn_propagate(errwarns, cur->line); 
        if (retval != 0) 
            return retval; 
        cur = STAILQ_NEXT(cur, link); 
    } 
    return 0; 
} 
 
const char * 
yasm_section_get_name(const yasm_section *sect) 
{ 
    return sect->name; 
} 
 
void 
yasm_section_set_align(yasm_section *sect, unsigned long align, 
                       unsigned long line) 
{ 
    sect->align = align; 
} 
 
unsigned long 
yasm_section_get_align(const yasm_section *sect) 
{ 
    return sect->align; 
} 
 
static void 
yasm_section_destroy(yasm_section *sect) 
{ 
    yasm_bytecode *cur, *next; 
    yasm_reloc *r_cur, *r_next; 
 
    if (!sect) 
        return; 
 
    yasm_xfree(sect->name); 
    yasm__assoc_data_destroy(sect->assoc_data); 
 
    /* Delete bytecodes */ 
    cur = STAILQ_FIRST(&sect->bcs); 
    while (cur) { 
        next = STAILQ_NEXT(cur, link); 
        yasm_bc_destroy(cur); 
        cur = next; 
    } 
 
    /* Delete relocations */ 
    r_cur = STAILQ_FIRST(&sect->relocs); 
    while (r_cur) { 
        r_next = STAILQ_NEXT(r_cur, link); 
        yasm_intnum_destroy(r_cur->addr); 
        sect->destroy_reloc(r_cur); 
        r_cur = r_next; 
    } 
 
    yasm_xfree(sect); 
} 
 
void 
yasm_section_print(const yasm_section *sect, FILE *f, int indent_level, 
                   int print_bcs) 
{ 
    if (!sect) { 
        fprintf(f, "%*s(none)\n", indent_level, ""); 
        return; 
    } 
 
    fprintf(f, "%*sname=%s\n", indent_level, "", sect->name); 
 
    if (sect->assoc_data) { 
        fprintf(f, "%*sAssociated data:\n", indent_level, ""); 
        yasm__assoc_data_print(sect->assoc_data, f, indent_level+1); 
    } 
 
    if (print_bcs) { 
        yasm_bytecode *cur; 
 
        fprintf(f, "%*sBytecodes:\n", indent_level, ""); 
 
        STAILQ_FOREACH(cur, &sect->bcs, link) { 
            fprintf(f, "%*sNext Bytecode:\n", indent_level+1, ""); 
            yasm_bc_print(cur, f, indent_level+2); 
        } 
    } 
} 
 
/* 
 * Robertson (1977) optimizer 
 * Based (somewhat loosely) on the algorithm given in: 
 *   MRC Technical Summary Report # 1779 
 *   CODE GENERATION FOR SHORT/LONG ADDRESS MACHINES 
 *   Edward L. Robertson 
 *   Mathematics Research Center 
 *   University of Wisconsin-Madison 
 *   610 Walnut Street 
 *   Madison, Wisconsin 53706 
 *   August 1977 
 * 
 * Key components of algorithm: 
 *  - start assuming all short forms 
 *  - build spans for short->long transition dependencies 
 *  - if a long form is needed, walk the dependencies and update 
 * Major differences from Robertson's algorithm: 
 *  - detection of cycles 
 *  - any difference of two locations is allowed 
 *  - handling of alignment/org gaps (offset setting) 
 *  - handling of multiples 
 * 
 * Data structures: 
 *  - Interval tree to store spans and associated data 
 *  - Queues QA and QB 
 * 
 * Each span keeps track of: 
 *  - Associated bytecode (bytecode that depends on the span length) 
 *  - Active/inactive state (starts out active) 
 *  - Sign (negative/positive; negative being "backwards" in address) 
 *  - Current length in bytes 
 *  - New length in bytes 
 *  - Negative/Positive thresholds 
 *  - Span ID (unique within each bytecode) 
 * 
 * How org and align and any other offset-based bytecodes are handled: 
 * 
 * Some portions are critical values that must not depend on any bytecode 
 * offset (either relative or absolute). 
 * 
 * All offset-setters (ORG and ALIGN) are put into a linked list in section 
 * order (e.g. increasing offset order).  Each span keeps track of the next 
 * offset-setter following the span's associated bytecode. 
 * 
 * When a bytecode is expanded, the next offset-setter is examined.  The 
 * offset-setter may be able to absorb the expansion (e.g. any offset 
 * following it would not change), or it may have to move forward (in the 
 * case of align) or error (in the case of org).  If it has to move forward, 
 * following offset-setters must also be examined for absorption or moving 
 * forward.  In either case, the ongoing offset is updated as well as the 
 * lengths of any spans dependent on the offset-setter. 
 * 
 * Alignment/ORG value is critical value. 
 * Cannot be combined with TIMES. 
 * 
 * How times is handled: 
 * 
 * TIMES: Handled separately from bytecode "raw" size.  If not span-dependent, 
 *      trivial (just multiplied in at any bytecode size increase).  Span 
 *      dependent times update on any change (span ID 0).  If the resultant 
 *      next bytecode offset would be less than the old next bytecode offset, 
 *      error.  Otherwise increase offset and update dependent spans. 
 * 
 * To reduce interval tree size, a first expansion pass is performed 
 * before the spans are added to the tree. 
 * 
 * Basic algorithm outline: 
 * 
 * 1. Initialization: 
 *  a. Number bytecodes sequentially (via bc_index) and calculate offsets 
 *     of all bytecodes assuming minimum length, building a list of all 
 *     dependent spans as we go. 
 *     "minimum" here means absolute minimum: 
 *      - align/org (offset-based) bumps offset as normal 
 *      - times values (with span-dependent values) assumed to be 0 
 *  b. Iterate over spans.  Set span length based on bytecode offsets 
 *     determined in 1a.  If span is "certainly" long because the span 
 *     is an absolute reference to another section (or external) or the 
 *     distance calculated based on the minimum length is greater than the 
 *     span's threshold, expand the span's bytecode, and if no further 
 *     expansion can result, mark span as inactive. 
 *  c. Iterate over bytecodes to update all bytecode offsets based on new 
 *     (expanded) lengths calculated in 1b. 
 *  d. Iterate over active spans.  Add span to interval tree.  Update span's 
 *     length based on new bytecode offsets determined in 1c.  If span's 
 *     length exceeds long threshold, add that span to Q. 
 * 2. Main loop: 
 *   While Q not empty: 
 *     Expand BC dependent on span at head of Q (and remove span from Q). 
 *     Update span: 
 *       If BC no longer dependent on span, mark span as inactive. 
 *       If BC has new thresholds for span, update span. 
 *     If BC increased in size, for each active span that contains BC: 
 *       Increase span length by difference between short and long BC length. 
 *       If span exceeds long threshold (or is flagged to recalculate on any 
 *       change), add it to tail of Q. 
 * 3. Final pass over bytecodes to generate final offsets. 
 */ 
 
typedef struct yasm_span yasm_span; 
 
typedef struct yasm_offset_setter { 
    /* Linked list in section order (e.g. offset order) */ 
    /*@reldef@*/ STAILQ_ENTRY(yasm_offset_setter) link; 
 
    /*@dependent@*/ yasm_bytecode *bc; 
 
    unsigned long cur_val, new_val; 
    unsigned long thres; 
} yasm_offset_setter; 
 
typedef struct yasm_span_term { 
    yasm_bytecode *precbc, *precbc2; 
    yasm_span *span;        /* span this term is a member of */ 
    long cur_val, new_val; 
    unsigned int subst; 
} yasm_span_term; 
 
struct yasm_span { 
    /*@reldef@*/ TAILQ_ENTRY(yasm_span) link;   /* for allocation tracking */ 
    /*@reldef@*/ STAILQ_ENTRY(yasm_span) linkq; /* for Q */ 
 
    /*@dependent@*/ yasm_bytecode *bc; 
 
    yasm_value depval; 
 
    /* span term for relative portion of value */ 
    yasm_span_term *rel_term; 
    /* span terms in absolute portion of value */ 
    yasm_span_term *terms; 
    yasm_expr__item *items; 
    unsigned int num_terms; 
 
    long cur_val; 
    long new_val; 
 
    long neg_thres; 
    long pos_thres; 
 
    int id; 
 
    int active; 
 
    /* NULL-terminated array of spans that led to this span.  Used only for 
     * checking for circular references (cycles) with id=0 spans. 
     */ 
    yasm_span **backtrace; 
    int backtrace_size; 
 
    /* First offset setter following this span's bytecode */ 
    yasm_offset_setter *os; 
}; 
 
typedef struct optimize_data { 
    /*@reldef@*/ TAILQ_HEAD(yasm_span_head, yasm_span) spans; 
    /*@reldef@*/ STAILQ_HEAD(yasm_span_shead, yasm_span) QA, QB; 
    /*@only@*/ IntervalTree *itree; 
    /*@reldef@*/ STAILQ_HEAD(offset_setters_head, yasm_offset_setter) 
        offset_setters; 
    long len_diff;      /* used only for optimize_term_expand */ 
    yasm_span *span;    /* used only for check_cycle */ 
    yasm_offset_setter *os; 
} optimize_data; 
 
static yasm_span * 
create_span(yasm_bytecode *bc, int id, /*@null@*/ const yasm_value *value,  
            long neg_thres, long pos_thres, yasm_offset_setter *os) 
{ 
    yasm_span *span = yasm_xmalloc(sizeof(yasm_span)); 
 
    span->bc = bc; 
    if (value) 
        yasm_value_init_copy(&span->depval, value); 
    else 
        yasm_value_initialize(&span->depval, NULL, 0); 
    span->rel_term = NULL; 
    span->terms = NULL; 
    span->items = NULL; 
    span->num_terms = 0; 
    span->cur_val = 0; 
    span->new_val = 0; 
    span->neg_thres = neg_thres; 
    span->pos_thres = pos_thres; 
    span->id = id; 
    span->active = 1; 
    span->backtrace = NULL; 
    span->backtrace_size = 0; 
    span->os = os; 
 
    return span; 
} 
 
static void 
optimize_add_span(void *add_span_data, yasm_bytecode *bc, int id, 
                  const yasm_value *value, long neg_thres, long pos_thres) 
{ 
    optimize_data *optd = (optimize_data *)add_span_data; 
    yasm_span *span; 
    span = create_span(bc, id, value, neg_thres, pos_thres, optd->os); 
    TAILQ_INSERT_TAIL(&optd->spans, span, link); 
} 
 
static void 
add_span_term(unsigned int subst, yasm_bytecode *precbc, 
              yasm_bytecode *precbc2, void *d) 
{ 
    yasm_span *span = d; 
    yasm_intnum *intn; 
 
    if (subst >= span->num_terms) { 
        /* Linear expansion since total number is essentially always small */ 
        span->num_terms = subst+1; 
        span->terms = yasm_xrealloc(span->terms, 
                                    span->num_terms*sizeof(yasm_span_term)); 
    } 
    span->terms[subst].precbc = precbc; 
    span->terms[subst].precbc2 = precbc2; 
    span->terms[subst].span = span; 
    span->terms[subst].subst = subst; 
 
    intn = yasm_calc_bc_dist(precbc, precbc2); 
    if (!intn) 
        yasm_internal_error(N_("could not calculate bc distance")); 
    span->terms[subst].cur_val = 0; 
    span->terms[subst].new_val = yasm_intnum_get_int(intn); 
    yasm_intnum_destroy(intn); 
} 
 
static void 
span_create_terms(yasm_span *span) 
{ 
    unsigned int i; 
 
    /* Split out sym-sym terms in absolute portion of dependent value */ 
    if (span->depval.abs) { 
        span->num_terms = yasm_expr__bc_dist_subst(&span->depval.abs, span, 
                                                   add_span_term); 
        if (span->num_terms > 0) { 
            span->items = yasm_xmalloc(span->num_terms*sizeof(yasm_expr__item)); 
            for (i=0; i<span->num_terms; i++) { 
                /* Create items with dummy value */ 
                span->items[i].type = YASM_EXPR_INT; 
                span->items[i].data.intn = yasm_intnum_create_int(0); 
 
                /* Check for circular references */ 
                if (span->id <= 0 && 
                    ((span->bc->bc_index > span->terms[i].precbc->bc_index && 
                      span->bc->bc_index <= span->terms[i].precbc2->bc_index) || 
                     (span->bc->bc_index > span->terms[i].precbc2->bc_index && 
                      span->bc->bc_index <= span->terms[i].precbc->bc_index))) 
                    yasm_error_set(YASM_ERROR_VALUE, 
                                   N_("circular reference detected")); 
            } 
        } 
    } 
 
    /* Create term for relative portion of dependent value */ 
    if (span->depval.rel) { 
        yasm_bytecode *rel_precbc; 
        int sym_local; 
 
        sym_local = yasm_symrec_get_label(span->depval.rel, &rel_precbc); 
        if (span->depval.wrt || span->depval.seg_of || span->depval.section_rel 
            || !sym_local) 
            return;     /* we can't handle SEG, WRT, or external symbols */ 
        if (rel_precbc->section != span->bc->section) 
            return;     /* not in this section */ 
        if (!span->depval.curpos_rel) 
            return;     /* not PC-relative */ 
 
        span->rel_term = yasm_xmalloc(sizeof(yasm_span_term)); 
        span->rel_term->precbc = NULL; 
        span->rel_term->precbc2 = rel_precbc; 
        span->rel_term->span = span; 
        span->rel_term->subst = ~0U; 
 
        span->rel_term->cur_val = 0; 
        span->rel_term->new_val = yasm_bc_next_offset(rel_precbc) - 
            span->bc->offset; 
    } 
} 
 
/* Recalculate span value based on current span replacement values. 
 * Returns 1 if span needs expansion (e.g. exceeded thresholds). 
 */ 
static int 
recalc_normal_span(yasm_span *span) 
{ 
    span->new_val = 0; 
 
    if (span->depval.abs) { 
        yasm_expr *abs_copy = yasm_expr_copy(span->depval.abs); 
        /*@null@*/ /*@dependent@*/ yasm_intnum *num; 
 
        /* Update sym-sym terms and substitute back into expr */ 
        unsigned int i; 
        for (i=0; i<span->num_terms; i++) 
            yasm_intnum_set_int(span->items[i].data.intn, 
                                span->terms[i].new_val); 
        yasm_expr__subst(abs_copy, span->num_terms, span->items); 
        num = yasm_expr_get_intnum(&abs_copy, 0); 
        if (num) 
            span->new_val = yasm_intnum_get_int(num); 
        else 
            span->new_val = LONG_MAX; /* too complex; force to longest form */ 
        yasm_expr_destroy(abs_copy); 
    } 
 
    if (span->rel_term) { 
        if (span->new_val != LONG_MAX && span->rel_term->new_val != LONG_MAX) 
            span->new_val += span->rel_term->new_val >> span->depval.rshift; 
        else 
            span->new_val = LONG_MAX;   /* too complex; force to longest form */ 
    } else if (span->depval.rel) 
        span->new_val = LONG_MAX;   /* too complex; force to longest form */ 
 
    if (span->new_val == LONG_MAX) 
        span->active = 0; 
 
    /* If id<=0, flag update on any change */ 
    if (span->id <= 0) 
        return (span->new_val != span->cur_val); 
 
    return (span->new_val < span->neg_thres 
            || span->new_val > span->pos_thres); 
} 
 
/* Updates all bytecode offsets.  For offset-based bytecodes, calls expand 
 * to determine new length. 
 */ 
static int 
update_all_bc_offsets(yasm_object *object, yasm_errwarns *errwarns) 
{ 
    yasm_section *sect; 
    int saw_error = 0; 
 
    STAILQ_FOREACH(sect, &object->sections, link) { 
        unsigned long offset = 0; 
 
        yasm_bytecode *bc = STAILQ_FIRST(&sect->bcs); 
        yasm_bytecode *prevbc; 
 
        /* Skip our locally created empty bytecode first. */ 
        prevbc = bc; 
        bc = STAILQ_NEXT(bc, link); 
 
        /* Iterate through the remainder, if any. */ 
        while (bc) { 
            if (bc->callback->special == YASM_BC_SPECIAL_OFFSET) { 
                /* Recalculate/adjust len of offset-based bytecodes here */ 
                long neg_thres = 0; 
                long pos_thres = (long)yasm_bc_next_offset(bc); 
                int retval = yasm_bc_expand(bc, 1, 0, 
                                            (long)yasm_bc_next_offset(prevbc), 
                                            &neg_thres, &pos_thres); 
                yasm_errwarn_propagate(errwarns, bc->line); 
                if (retval < 0) 
                    saw_error = 1; 
            } 
            bc->offset = offset; 
            offset += bc->len*bc->mult_int; 
            prevbc = bc; 
            bc = STAILQ_NEXT(bc, link); 
        } 
    } 
    return saw_error; 
} 
 
static void 
span_destroy(/*@only@*/ yasm_span *span) 
{ 
    unsigned int i; 
 
    yasm_value_delete(&span->depval); 
    if (span->rel_term) 
        yasm_xfree(span->rel_term); 
    if (span->terms) 
        yasm_xfree(span->terms); 
    if (span->items) { 
        for (i=0; i<span->num_terms; i++) 
            yasm_intnum_destroy(span->items[i].data.intn); 
        yasm_xfree(span->items); 
    } 
    if (span->backtrace) 
        yasm_xfree(span->backtrace); 
    yasm_xfree(span); 
} 
 
static void 
optimize_cleanup(optimize_data *optd) 
{ 
    yasm_span *s1, *s2; 
    yasm_offset_setter *os1, *os2; 
 
    IT_destroy(optd->itree); 
 
    s1 = TAILQ_FIRST(&optd->spans); 
    while (s1) { 
        s2 = TAILQ_NEXT(s1, link); 
        span_destroy(s1); 
        s1 = s2; 
    } 
 
    os1 = STAILQ_FIRST(&optd->offset_setters); 
    while (os1) { 
        os2 = STAILQ_NEXT(os1, link); 
        yasm_xfree(os1); 
        os1 = os2; 
    } 
} 
 
static void 
optimize_itree_add(IntervalTree *itree, yasm_span *span, yasm_span_term *term) 
{ 
    long precbc_index, precbc2_index; 
    unsigned long low, high; 
 
    /* Update term length */ 
    if (term->precbc) 
        precbc_index = term->precbc->bc_index; 
    else 
        precbc_index = span->bc->bc_index-1; 
 
    if (term->precbc2) 
        precbc2_index = term->precbc2->bc_index; 
    else 
        precbc2_index = span->bc->bc_index-1; 
 
    if (precbc_index < precbc2_index) { 
        low = precbc_index+1; 
        high = precbc2_index; 
    } else if (precbc_index > precbc2_index) { 
        low = precbc2_index+1; 
        high = precbc_index; 
    } else 
        return;     /* difference is same bc - always 0! */ 
 
    IT_insert(itree, (long)low, (long)high, term); 
} 
 
static void 
check_cycle(IntervalTreeNode *node, void *d) 
{ 
    optimize_data *optd = d; 
    yasm_span_term *term = node->data; 
    yasm_span *depspan = term->span; 
    int i; 
    int depspan_bt_alloc; 
 
    /* Only check for cycles in id=0 spans */ 
    if (depspan->id > 0) 
        return; 
 
    /* Check for a circular reference by looking to see if this dependent 
     * span is in our backtrace. 
     */ 
    if (optd->span->backtrace) { 
        for (i=0; i<optd->span->backtrace_size; i++) { 
            if (optd->span->backtrace[i] == depspan) 
                yasm_error_set(YASM_ERROR_VALUE, 
                               N_("circular reference detected")); 
        } 
    } 
 
    /* Add our complete backtrace and ourselves to backtrace of dependent 
     * span. 
     */ 
    if (!depspan->backtrace) { 
        depspan->backtrace = yasm_xmalloc((optd->span->backtrace_size+1)* 
                                          sizeof(yasm_span *)); 
        if (optd->span->backtrace_size > 0) 
            memcpy(depspan->backtrace, optd->span->backtrace, 
                   optd->span->backtrace_size*sizeof(yasm_span *)); 
        depspan->backtrace[optd->span->backtrace_size] = optd->span; 
        depspan->backtrace_size = optd->span->backtrace_size+1; 
        return; 
    } 
 
    /* Add our complete backtrace, checking for duplicates */ 
    depspan_bt_alloc = depspan->backtrace_size; 
    for (i=0; i<optd->span->backtrace_size; i++) { 
        int present = 0; 
        int j; 
        for (j=0; j<depspan->backtrace_size; j++) { 
            if (optd->span->backtrace[i] == optd->span->backtrace[j]) { 
                present = 1; 
                break; 
            } 
        } 
        if (present) 
            continue; 
        /* Not already in array; add it. */ 
        if (depspan->backtrace_size >= depspan_bt_alloc) 
        { 
            depspan_bt_alloc *= 2; 
            depspan->backtrace = 
                yasm_xrealloc(depspan->backtrace, 
                              depspan_bt_alloc*sizeof(yasm_span *)); 
        } 
        depspan->backtrace[depspan->backtrace_size] = optd->span->backtrace[i]; 
        depspan->backtrace_size++; 
    } 
 
    /* Add ourselves. */ 
    if (depspan->backtrace_size >= depspan_bt_alloc) 
    { 
        depspan_bt_alloc++; 
        depspan->backtrace = 
            yasm_xrealloc(depspan->backtrace, 
                          depspan_bt_alloc*sizeof(yasm_span *)); 
    } 
    depspan->backtrace[depspan->backtrace_size] = optd->span; 
    depspan->backtrace_size++; 
} 
 
static void 
optimize_term_expand(IntervalTreeNode *node, void *d) 
{ 
    optimize_data *optd = d; 
    yasm_span_term *term = node->data; 
    yasm_span *span = term->span; 
    long len_diff = optd->len_diff; 
    long precbc_index, precbc2_index; 
 
    /* Don't expand inactive spans */ 
    if (!span->active) 
        return; 
 
    /* Update term length */ 
    if (term->precbc) 
        precbc_index = term->precbc->bc_index; 
    else 
        precbc_index = span->bc->bc_index-1; 
 
    if (term->precbc2) 
        precbc2_index = term->precbc2->bc_index; 
    else 
        precbc2_index = span->bc->bc_index-1; 
 
    if (precbc_index < precbc2_index) 
        term->new_val += len_diff; 
    else 
        term->new_val -= len_diff; 
 
    /* If already on Q, don't re-add */ 
    if (span->active == 2) 
        return; 
 
    /* Update term and check against thresholds */ 
    if (!recalc_normal_span(span)) 
        return; /* didn't exceed thresholds, we're done */ 
 
    /* Exceeded thresholds, need to add to Q for expansion */ 
    if (span->id <= 0) 
        STAILQ_INSERT_TAIL(&optd->QA, span, linkq); 
    else 
        STAILQ_INSERT_TAIL(&optd->QB, span, linkq); 
    span->active = 2;       /* Mark as being in Q */ 
} 
 
void 
yasm_object_optimize(yasm_object *object, yasm_errwarns *errwarns) 
{ 
    yasm_section *sect; 
    unsigned long bc_index = 0; 
    int saw_error = 0; 
    optimize_data optd; 
    yasm_span *span, *span_temp; 
    yasm_offset_setter *os; 
    int retval; 
    unsigned int i; 
 
    TAILQ_INIT(&optd.spans); 
    STAILQ_INIT(&optd.offset_setters); 
    optd.itree = IT_create(); 
 
    /* Create an placeholder offset setter for spans to point to; this will 
     * get updated if/when we actually run into one. 
     */ 
    os = yasm_xmalloc(sizeof(yasm_offset_setter)); 
    os->bc = NULL; 
    os->cur_val = 0; 
    os->new_val = 0; 
    os->thres = 0; 
    STAILQ_INSERT_TAIL(&optd.offset_setters, os, link); 
    optd.os = os; 
 
    /* Step 1a */ 
    STAILQ_FOREACH(sect, &object->sections, link) { 
        unsigned long offset = 0; 
 
        yasm_bytecode *bc = STAILQ_FIRST(&sect->bcs); 
 
        bc->bc_index = bc_index++; 
 
        /* Skip our locally created empty bytecode first. */ 
        bc = STAILQ_NEXT(bc, link); 
 
        /* Iterate through the remainder, if any. */ 
        while (bc) { 
            bc->bc_index = bc_index++; 
            bc->offset = offset; 
 
            retval = yasm_bc_calc_len(bc, optimize_add_span, &optd); 
            yasm_errwarn_propagate(errwarns, bc->line); 
            if (retval) 
                saw_error = 1; 
            else { 
                if (bc->callback->special == YASM_BC_SPECIAL_OFFSET) { 
                    /* Remember it as offset setter */ 
                    os->bc = bc; 
                    os->thres = yasm_bc_next_offset(bc); 
 
                    /* Create new placeholder */ 
                    os = yasm_xmalloc(sizeof(yasm_offset_setter)); 
                    os->bc = NULL; 
                    os->cur_val = 0; 
                    os->new_val = 0; 
                    os->thres = 0; 
                    STAILQ_INSERT_TAIL(&optd.offset_setters, os, link); 
                    optd.os = os; 
 
                    if (bc->multiple) { 
                        yasm_error_set(YASM_ERROR_VALUE, 
                            N_("cannot combine multiples and setting assembly position")); 
                        yasm_errwarn_propagate(errwarns, bc->line); 
                        saw_error = 1; 
                    } 
                } 
 
                offset += bc->len*bc->mult_int; 
            } 
 
            bc = STAILQ_NEXT(bc, link); 
        } 
    } 
 
    if (saw_error) { 
        optimize_cleanup(&optd); 
        return; 
    } 
 
    /* Step 1b */ 
    TAILQ_FOREACH_SAFE(span, &optd.spans, link, span_temp) { 
        span_create_terms(span); 
        if (yasm_error_occurred()) { 
            yasm_errwarn_propagate(errwarns, span->bc->line); 
            saw_error = 1; 
        } else if (recalc_normal_span(span)) { 
            retval = yasm_bc_expand(span->bc, span->id, span->cur_val, 
                                    span->new_val, &span->neg_thres, 
                                    &span->pos_thres); 
            yasm_errwarn_propagate(errwarns, span->bc->line); 
            if (retval < 0) 
                saw_error = 1; 
            else if (retval > 0) { 
                if (!span->active) { 
                    yasm_error_set(YASM_ERROR_VALUE, 
                        N_("secondary expansion of an external/complex value")); 
                    yasm_errwarn_propagate(errwarns, span->bc->line); 
                    saw_error = 1; 
                } 
            } else { 
                TAILQ_REMOVE(&optd.spans, span, link); 
                span_destroy(span); 
                continue; 
            } 
        } 
        span->cur_val = span->new_val; 
    } 
 
    if (saw_error) { 
        optimize_cleanup(&optd); 
        return; 
    } 
 
    /* Step 1c */ 
    if (update_all_bc_offsets(object, errwarns)) { 
        optimize_cleanup(&optd); 
        return; 
    } 
 
    /* Step 1d */ 
    STAILQ_INIT(&optd.QB); 
    TAILQ_FOREACH(span, &optd.spans, link) { 
        yasm_intnum *intn; 
 
        /* Update span terms based on new bc offsets */ 
        for (i=0; i<span->num_terms; i++) { 
            intn = yasm_calc_bc_dist(span->terms[i].precbc, 
                                     span->terms[i].precbc2); 
            if (!intn) 
                yasm_internal_error(N_("could not calculate bc distance")); 
            span->terms[i].cur_val = span->terms[i].new_val; 
            span->terms[i].new_val = yasm_intnum_get_int(intn); 
            yasm_intnum_destroy(intn); 
        } 
        if (span->rel_term) { 
            span->rel_term->cur_val = span->rel_term->new_val; 
            if (span->rel_term->precbc2) 
                span->rel_term->new_val = 
                    yasm_bc_next_offset(span->rel_term->precbc2) - 
                    span->bc->offset; 
            else 
                span->rel_term->new_val = span->bc->offset - 
                    yasm_bc_next_offset(span->rel_term->precbc); 
        } 
 
        if (recalc_normal_span(span)) { 
            /* Exceeded threshold, add span to QB */ 
            STAILQ_INSERT_TAIL(&optd.QB, span, linkq); 
            span->active = 2; 
        } 
    } 
 
    /* Do we need step 2?  If not, go ahead and exit. */ 
    if (STAILQ_EMPTY(&optd.QB)) { 
        optimize_cleanup(&optd); 
        return; 
    } 
 
    /* Update offset-setters values */ 
    STAILQ_FOREACH(os, &optd.offset_setters, link) { 
        if (!os->bc) 
            continue; 
        os->thres = yasm_bc_next_offset(os->bc); 
        os->new_val = os->bc->offset; 
        os->cur_val = os->new_val; 
    } 
 
    /* Build up interval tree */ 
    TAILQ_FOREACH(span, &optd.spans, link) { 
        for (i=0; i<span->num_terms; i++) 
            optimize_itree_add(optd.itree, span, &span->terms[i]); 
        if (span->rel_term) 
            optimize_itree_add(optd.itree, span, span->rel_term); 
    } 
 
    /* Look for cycles in times expansion (span.id==0) */ 
    TAILQ_FOREACH(span, &optd.spans, link) { 
        if (span->id > 0) 
            continue; 
        optd.span = span; 
        IT_enumerate(optd.itree, (long)span->bc->bc_index, 
                     (long)span->bc->bc_index, &optd, check_cycle); 
        if (yasm_error_occurred()) { 
            yasm_errwarn_propagate(errwarns, span->bc->line); 
            saw_error = 1; 
        } 
    } 
 
    if (saw_error) { 
        optimize_cleanup(&optd); 
        return; 
    } 
 
    /* Step 2 */ 
    STAILQ_INIT(&optd.QA); 
    while (!STAILQ_EMPTY(&optd.QA) || !(STAILQ_EMPTY(&optd.QB))) { 
        unsigned long orig_len; 
        long offset_diff; 
 
        /* QA is for TIMES, update those first, then update non-TIMES. 
         * This is so that TIMES can absorb increases before we look at 
         * expanding non-TIMES BCs. 
         */ 
        if (!STAILQ_EMPTY(&optd.QA)) { 
            span = STAILQ_FIRST(&optd.QA); 
            STAILQ_REMOVE_HEAD(&optd.QA, linkq); 
        } else { 
            span = STAILQ_FIRST(&optd.QB); 
            STAILQ_REMOVE_HEAD(&optd.QB, linkq); 
        } 
 
        if (!span->active) 
            continue; 
        span->active = 1;   /* no longer in Q */ 
 
        /* Make sure we ended up ultimately exceeding thresholds; due to 
         * offset BCs we may have been placed on Q and then reduced in size 
         * again. 
         */ 
        if (!recalc_normal_span(span)) 
            continue; 
 
        orig_len = span->bc->len * span->bc->mult_int; 
 
        retval = yasm_bc_expand(span->bc, span->id, span->cur_val, 
                                span->new_val, &span->neg_thres, 
                                &span->pos_thres); 
        yasm_errwarn_propagate(errwarns, span->bc->line); 
 
        if (retval < 0) { 
            /* error */ 
            saw_error = 1; 
            continue; 
        } else if (retval > 0) { 
            /* another threshold, keep active */ 
            for (i=0; i<span->num_terms; i++) 
                span->terms[i].cur_val = span->terms[i].new_val; 
            if (span->rel_term) 
                span->rel_term->cur_val = span->rel_term->new_val; 
            span->cur_val = span->new_val; 
        } else 
            span->active = 0;       /* we're done with this span */ 
 
        optd.len_diff = span->bc->len * span->bc->mult_int - orig_len; 
        if (optd.len_diff == 0) 
            continue;   /* didn't increase in size */ 
 
        /* Iterate over all spans dependent across the bc just expanded */ 
        IT_enumerate(optd.itree, (long)span->bc->bc_index, 
                     (long)span->bc->bc_index, &optd, optimize_term_expand); 
 
        /* Iterate over offset-setters that follow the bc just expanded. 
         * Stop iteration if: 
         *  - no more offset-setters in this section 
         *  - offset-setter didn't move its following offset 
         */ 
        os = span->os; 
        offset_diff = optd.len_diff; 
        while (os->bc && os->bc->section == span->bc->section 
               && offset_diff != 0) { 
            unsigned long old_next_offset = os->cur_val + os->bc->len; 
            long neg_thres_temp; 
 
            if (offset_diff < 0 && (unsigned long)(-offset_diff) > os->new_val) 
                yasm_internal_error(N_("org/align went to negative offset")); 
            os->new_val += offset_diff; 
 
            orig_len = os->bc->len; 
            retval = yasm_bc_expand(os->bc, 1, (long)os->cur_val, 
                                    (long)os->new_val, &neg_thres_temp, 
                                    (long *)&os->thres); 
            yasm_errwarn_propagate(errwarns, os->bc->line); 
 
            offset_diff = os->new_val + os->bc->len - old_next_offset; 
            optd.len_diff = os->bc->len - orig_len; 
            if (optd.len_diff != 0) 
                IT_enumerate(optd.itree, (long)os->bc->bc_index, 
                     (long)os->bc->bc_index, &optd, optimize_term_expand); 
 
            os->cur_val = os->new_val; 
            os = STAILQ_NEXT(os, link); 
        } 
    } 
 
    if (saw_error) { 
        optimize_cleanup(&optd); 
        return; 
    } 
 
    /* Step 3 */ 
    update_all_bc_offsets(object, errwarns); 
    optimize_cleanup(&optd); 
}