outieee.c

开源的nasm编译器源码,研究编译器原理很有帮且

/* outieee.c	output routines for the Netwide Assembler to produce
 *		IEEE-std object files
 *
 * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
 * Julian Hall. All rights reserved. The software is
 * redistributable under the licence given in the file "Licence"
 * distributed in the NASM archive.
 */

/* notes: I have tried to make this correspond to the IEEE version
 * of the standard, specifically the primary ASCII version.  It should
 * be trivial to create the binary version given this source (which is
 * one of MANY things that have to be done to make this correspond to
 * the hp-microtek version of the standard).
 *
 * 16-bit support is assumed to use 24-bit addresses
 * The linker can sort out segmentation-specific stuff
 * if it keeps track of externals
 * in terms of being relative to section bases
 *
 * A non-standard variable type, the 'Yn' variable, has been introduced.
 * Basically it is a reference to extern 'n'- denoting the low limit
 * (L-variable) of the section that extern 'n' is defined in.  Like the
 * x variable, there may be no explicit assignment to it, it is derived
 * from the public definition corresponding to the extern name.  This
 * is required because the one thing the mufom guys forgot to do well was
 * take into account segmented architectures.
 *
 * I use comment classes for various things and these are undefined by
 * the standard.
 *
 * Debug info should be considered totally non-standard (local labels are
 * standard but linenum records are not covered by the standard.
 * Type defs have the standard format but absolute meanings for ordinal
 * types are not covered by the standard.)
 *
 * David Lindauer, LADsoft
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <stdarg.h>  /* Note: we need the ANSI version of stdarg.h */
#include <ctype.h>

#include "nasm.h"
#include "nasmlib.h"
#include "outform.h"

#ifdef OF_IEEE

#define ARRAY_BOT 0x1

static char ieee_infile[FILENAME_MAX];
static int ieee_uppercase;

static efunc error;
static ldfunc deflabel;
static FILE *ofp;
static int any_segs;
static int arrindex;

#define HUNKSIZE 1024		       /* Size of the data hunk */
#define EXT_BLKSIZ 512
#define LDPERLINE 32			/* bytes per line in output */

struct ieeeSection;

struct LineNumber {
    struct LineNumber *next;
    struct ieeeSection *segment;
    long offset;
    long lineno;
};

static struct FileName {
    struct FileName *next;
    char *name;
    long index;
} *fnhead, **fntail;

static struct Array {
    struct Array *next;
    unsigned size;
    int basetype;
} *arrhead, **arrtail;

static struct ieeePublic {
    struct ieeePublic *next;
    char *name;
    long offset;
    long segment;		       /* only if it's far-absolute */
    long index;
    int type;	 			/* for debug purposes */	
} *fpubhead, **fpubtail, *last_defined;

static struct ieeeExternal {
    struct ieeeExternal *next;
    char *name;
    long commonsize;
} *exthead, **exttail;

static int externals;

static struct ExtBack {
    struct ExtBack *next;
    int index[EXT_BLKSIZ];
} *ebhead, **ebtail;

/* NOTE: the first segment MUST be the lineno segment */
static struct ieeeSection {
    struct ieeeObjData *data,*datacurr;
    struct ieeeSection *next;
    struct ieeeFixupp *fptr, * flptr;
    long index;			       /* the NASM segment id */
    long ieee_index;		       /* the OBJ-file segment index */
    long currentpos;
    long align;			       /* can be SEG_ABS + absolute addr */
    long startpos;
    enum {
	CMB_PRIVATE = 0,
	CMB_PUBLIC = 2,
	CMB_COMMON = 6
    } combine;
    long use32;			       /* is this segment 32-bit? */
    struct ieeePublic *pubhead, **pubtail, *lochead, **loctail;
    char *name;
} *seghead, **segtail, *ieee_seg_needs_update;

struct ieeeObjData {
    struct ieeeObjData *next;
    unsigned char data[HUNKSIZE];
};

struct ieeeFixupp {
    struct ieeeFixupp *next;
    enum { 
	FT_SEG = 0,
	FT_REL = 1,
	FT_OFS = 2,
	FT_EXT = 3,
	FT_WRT = 4,
	FT_EXTREL = 5,
	FT_EXTWRT = 6,
	FT_EXTSEG = 7
    } ftype;
    short size;
    long id1;
    long id2;
    long offset;
    long addend;
};
		
static long ieee_entry_seg, ieee_entry_ofs;
static int checksum;

extern struct ofmt of_ieee;

static void ieee_data_new(struct ieeeSection *);
static void ieee_write_fixup (long, long, struct ieeeSection *,
				int, unsigned long, long);
static void ieee_install_fixup(struct ieeeSection *, struct ieeeFixupp *);
static long ieee_segment (char *, int, int *);
static void ieee_write_file(int debuginfo);
static void ieee_write_byte(struct ieeeSection *, int);
static void ieee_write_word(struct ieeeSection *, int);
static void ieee_write_dword(struct ieeeSection *, long);
static void ieee_putascii(char *, ...);
static void ieee_putcs(int);
static long ieee_putld(long, long, unsigned char *);
static long ieee_putlr(struct ieeeFixupp *);
static void ieee_unqualified_name(char *, char *);


/* 
 * pup init 
 */
static void ieee_init (FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval) 
{
    (void) eval;
    ofp = fp;
    error = errfunc;
    deflabel = ldef;
    any_segs = FALSE;
    fpubhead = NULL;
    fpubtail = &fpubhead;
    exthead = NULL;
    exttail = &exthead;
    externals = 1;
    ebhead = NULL;
    ebtail = &ebhead;
    seghead = ieee_seg_needs_update = NULL;
    segtail = &seghead;
    ieee_entry_seg = NO_SEG;
    ieee_uppercase = FALSE;
    checksum = 0;
    of_ieee.current_dfmt->init (&of_ieee,NULL,fp,errfunc);
}
static int ieee_set_info(enum geninfo type, char **val)
{
    (void) type;
    (void) val;

    return 0;
}
/*
 * Rundown
 */
static void ieee_cleanup (int debuginfo) 
{
    ieee_write_file(debuginfo);
    of_ieee.current_dfmt->cleanup ();
    fclose (ofp);
    while (seghead) {
	struct ieeeSection *segtmp = seghead;
	seghead = seghead->next;
	while (segtmp->pubhead) {
	    struct ieeePublic *pubtmp = segtmp->pubhead;
	    segtmp->pubhead = pubtmp->next;
	    nasm_free (pubtmp);
	}
	while (segtmp->fptr) {
	    struct ieeeFixupp *fixtmp = segtmp->fptr;
	    segtmp->fptr = fixtmp->next;
	    nasm_free(fixtmp);
	}
	while (segtmp->data) {
	    struct ieeeObjData *dattmp = segtmp->data;
	    segtmp->data = dattmp->next;
	    nasm_free(dattmp);
	}
	nasm_free (segtmp);
    }
    while (fpubhead) {
	struct ieeePublic *pubtmp = fpubhead;
	fpubhead = fpubhead->next;
	nasm_free (pubtmp);
    }
    while (exthead) {
	struct ieeeExternal *exttmp = exthead;
	exthead = exthead->next;
	nasm_free (exttmp);
    }
    while (ebhead) {
	struct ExtBack *ebtmp = ebhead;
	ebhead = ebhead->next;
	nasm_free (ebtmp);
    }
}
/*
 * callback for labels
 */
static void ieee_deflabel (char *name, long segment,
			  long offset, int is_global, char *special) {
    /*
     * We have three cases:
     *
     * (i) `segment' is a segment-base. If so, set the name field
     * for the segment structure it refers to, and then
     * return.
     *
     * (ii) `segment' is one of our segments, or a SEG_ABS segment.
     * Save the label position for later output of a PUBDEF record.
     * 
     *
     * (iii) `segment' is not one of our segments. Save the label
     * position for later output of an EXTDEF.
     */
    struct ieeeExternal *ext;
    struct ExtBack *eb;
    struct ieeeSection *seg;
    int i;

    if (special) {
        error(ERR_NONFATAL, "unrecognised symbol type `%s'", special);
    }
    /*
     * First check for the double-period, signifying something
     * unusual.
     */
    if (name[0] == '.' && name[1] == '.') {
	if (!strcmp(name, "..start")) {
	    ieee_entry_seg = segment;
	    ieee_entry_ofs = offset;
	}
	return;
    }

    /*
     * Case (i):
     */
    if (ieee_seg_needs_update) {
	ieee_seg_needs_update->name = name;
	return;
    } 
    if (segment < SEG_ABS && segment != NO_SEG && segment % 2)
	return;

    /*
     * case (ii)
     */
    if (segment >= SEG_ABS) {
	/*
	 * SEG_ABS subcase of (ii).
	 */
	if (is_global) {
	    struct ieeePublic *pub;

	    pub = *fpubtail = nasm_malloc(sizeof(*pub));
	    fpubtail = &pub->next;
	    pub->next = NULL;
	    pub->name = name;
	    pub->offset = offset;
	    pub->segment = segment & ~SEG_ABS;
	}
	return;
    }

    for (seg = seghead; seg && is_global; seg = seg->next)
	if (seg->index == segment) {
		struct ieeePublic *pub;

	    last_defined = pub = *seg->pubtail = nasm_malloc(sizeof(*pub));
	    seg->pubtail = &pub->next;
	    pub->next = NULL;
	    pub->name = name;
	    pub->offset = offset;
	    pub->index = seg->ieee_index;
	    pub->segment = -1;
	    return;
	}

    /*
     * Case (iii).
     */
    if (is_global) {
        ext = *exttail = nasm_malloc(sizeof(*ext));
        ext->next = NULL;
        exttail = &ext->next;
        ext->name = name;
        if (is_global == 2)
	    ext->commonsize = offset;
    	else
	    ext->commonsize = 0;
    	i = segment/2;
    	eb = ebhead;
    	if (!eb) {
	    eb = *ebtail = nasm_malloc(sizeof(*eb));
	    eb->next = NULL;
	    ebtail = &eb->next;
        }
    	while (i > EXT_BLKSIZ) {
	    if (eb && eb->next)
	        eb = eb->next;
	    else {
	        eb = *ebtail = nasm_malloc(sizeof(*eb));
	    	eb->next = NULL;
	    	ebtail = &eb->next;
	    }
	    i -= EXT_BLKSIZ;
    	}
        eb->index[i] = externals++;
    }
	
}

/*
 * Put data out
 */
static void ieee_out (long segto, const void *data, unsigned long type,
		     long segment, long wrt) {
    unsigned long size, realtype;
    const unsigned char *ucdata;
    long ldata;
    struct ieeeSection *seg;

    /*
     * handle absolute-assembly (structure definitions)
     */
    if (segto == NO_SEG) {
	if ((type & OUT_TYPMASK) != OUT_RESERVE)
	    error (ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
		   " space");
	return;
    }

    /*
     * If `any_segs' is still FALSE, we must define a default
     * segment.
     */
    if (!any_segs) {
	int tempint;		       /* ignored */
	if (segto != ieee_segment("__NASMDEFSEG", 2, &tempint))
	    error (ERR_PANIC, "strange segment conditions in IEEE driver");
    }

    /*
     * Find the segment we are targetting.
     */
    for (seg = seghead; seg; seg = seg->next)
	if (seg->index == segto)
	    break;
    if (!seg)
	error (ERR_PANIC, "code directed to nonexistent segment?");

    size = type & OUT_SIZMASK;
    realtype = type & OUT_TYPMASK;
    if (realtype == OUT_RAWDATA) {
	ucdata = data;
	while (size--)
	    ieee_write_byte(seg,*ucdata++);
    } else if (realtype == OUT_ADDRESS || realtype == OUT_REL2ADR ||
	       realtype == OUT_REL4ADR) {
	if (segment == NO_SEG && realtype != OUT_ADDRESS)
	    error(ERR_NONFATAL, "relative call to absolute address not"
		  " supported by IEEE format");
	ldata = *(long *)data;
	if (realtype == OUT_REL2ADR)
	    ldata += (size-2);
	if (realtype == OUT_REL4ADR)
	    ldata += (size-4);
	ieee_write_fixup (segment, wrt, seg, size, realtype,ldata);
	if (size == 2)
	    ieee_write_word (seg, ldata);
	else
	    ieee_write_dword (seg, ldata);
    } 
    else if (realtype == OUT_RESERVE) {
	while (size--)
	    ieee_write_byte(seg,0);
    }
}

static void ieee_data_new(struct ieeeSection *segto) {
    
    if (!segto->data)
	segto->data = segto->datacurr = nasm_malloc(sizeof(*(segto->datacurr)));
    else
	segto->datacurr = segto->datacurr->next = nasm_malloc(sizeof(*(segto->datacurr)));
    segto->datacurr->next = NULL;
}


/*
 * this routine is unalduterated bloatware.  I usually don't do this
 * but I might as well see what it is like on a harmless program.
 * If anyone wants to optimize this is a good canditate!
 */
static void ieee_write_fixup (long segment, long wrt, struct ieeeSection * segto,
				int size, unsigned long realtype, long offset) {
    struct ieeeSection *target;
    struct ieeeFixupp s;

    /* Don't put a fixup for things NASM can calculate */
    if (wrt == NO_SEG && segment == NO_SEG)
	return;

    s.ftype = -1;
    /* if it is a WRT offset */
    if (wrt != NO_SEG) {
	s.ftype = FT_WRT;
	s.addend = offset;
	if (wrt >= SEG_ABS)
	    s.id1 = -(wrt-SEG_ABS);
	else {
	    if (wrt %2 && realtype != OUT_REL2ADR && realtype != OUT_REL4ADR) {
		wrt--;

	    	for (target = seghead; target; target = target->next)
	            if (target->index == wrt)
	            	break;
    	        if (target) {
	            s.id1 = target->ieee_index;
	    	    for (target = seghead; target; target = target->next)
	            	if (target->index == segment)
	            	    break;
		
		    if (target) 
		    	s.id2 = target->ieee_index;
	            else {
			/*
			 * Now we assume the segment field is being used
			 * to hold an extern index
		 	 */
			long i = segment/2;
			struct ExtBack *eb = ebhead;
			while (i > EXT_BLKSIZ) {
			    if (eb)