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/*
* Align bytecode
*
* Copyright (C) 2005-2007 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 "libyasm-stdint.h"
#include "coretype.h"
#include "errwarn.h"
#include "intnum.h"
#include "expr.h"
#include "bytecode.h"
typedef struct bytecode_align {
/*@only@*/ yasm_expr *boundary; /* alignment boundary */
/* What to fill intervening locations with, NULL if using code_fill */
/*@only@*/ /*@null@*/ yasm_expr *fill;
/* Maximum number of bytes to skip, NULL if no maximum. */
/*@only@*/ /*@null@*/ yasm_expr *maxskip;
/* Code fill, NULL if using 0 fill */
/*@null@*/ const unsigned char **code_fill;
} bytecode_align;
static void bc_align_destroy(void *contents);
static void bc_align_print(const void *contents, FILE *f, int indent_level);
static void bc_align_finalize(yasm_bytecode *bc, yasm_bytecode *prev_bc);
static int bc_align_calc_len(yasm_bytecode *bc, yasm_bc_add_span_func add_span,
void *add_span_data);
static int bc_align_expand(yasm_bytecode *bc, int span, long old_val,
long new_val, /*@out@*/ long *neg_thres,
/*@out@*/ long *pos_thres);
static int bc_align_tobytes(yasm_bytecode *bc, unsigned char **bufp,
unsigned char *bufstart, void *d,
yasm_output_value_func output_value,
/*@null@*/ yasm_output_reloc_func output_reloc);
static const yasm_bytecode_callback bc_align_callback = {
bc_align_destroy,
bc_align_print,
bc_align_finalize,
NULL,
bc_align_calc_len,
bc_align_expand,
bc_align_tobytes,
YASM_BC_SPECIAL_OFFSET
};
static void
bc_align_destroy(void *contents)
{
bytecode_align *align = (bytecode_align *)contents;
if (align->boundary)
yasm_expr_destroy(align->boundary);
if (align->fill)
yasm_expr_destroy(align->fill);
if (align->maxskip)
yasm_expr_destroy(align->maxskip);
yasm_xfree(contents);
}
static void
bc_align_print(const void *contents, FILE *f, int indent_level)
{
const bytecode_align *align = (const bytecode_align *)contents;
fprintf(f, "%*s_Align_\n", indent_level, "");
fprintf(f, "%*sBoundary=", indent_level, "");
yasm_expr_print(align->boundary, f);
fprintf(f, "\n%*sFill=", indent_level, "");
yasm_expr_print(align->fill, f);
fprintf(f, "\n%*sMax Skip=", indent_level, "");
yasm_expr_print(align->maxskip, f);
fprintf(f, "\n");
}
static void
bc_align_finalize(yasm_bytecode *bc, yasm_bytecode *prev_bc)
{
bytecode_align *align = (bytecode_align *)bc->contents;
if (!yasm_expr_get_intnum(&align->boundary, 0))
yasm_error_set(YASM_ERROR_NOT_CONSTANT,
N_("align boundary must be a constant"));
if (align->fill && !yasm_expr_get_intnum(&align->fill, 0))
yasm_error_set(YASM_ERROR_NOT_CONSTANT,
N_("align fill must be a constant"));
if (align->maxskip && !yasm_expr_get_intnum(&align->maxskip, 0))
yasm_error_set(YASM_ERROR_NOT_CONSTANT,
N_("align maximum skip must be a constant"));
}
static int
bc_align_calc_len(yasm_bytecode *bc, yasm_bc_add_span_func add_span,
void *add_span_data)
{
long neg_thres = 0;
long pos_thres = 0;
if (bc_align_expand(bc, 0, 0, (long)bc->offset, &neg_thres,
&pos_thres) < 0)
return -1;
return 0;
}
static int
bc_align_expand(yasm_bytecode *bc, int span, long old_val, long new_val,
/*@out@*/ long *neg_thres, /*@out@*/ long *pos_thres)
{
bytecode_align *align = (bytecode_align *)bc->contents;
unsigned long end;
unsigned long boundary =
yasm_intnum_get_uint(yasm_expr_get_intnum(&align->boundary, 0));
if (boundary == 0) {
bc->len = 0;
*pos_thres = new_val;
return 0;
}
end = (unsigned long)new_val;
if ((unsigned long)new_val & (boundary-1))
end = ((unsigned long)new_val & ~(boundary-1)) + boundary;
*pos_thres = (long)end;
bc->len = end - (unsigned long)new_val;
if (align->maxskip) {
unsigned long maxskip =
yasm_intnum_get_uint(yasm_expr_get_intnum(&align->maxskip, 0));
if (bc->len > maxskip) {
*pos_thres = (long)end-maxskip-1;
bc->len = 0;
}
}
return 1;
}
static int
bc_align_tobytes(yasm_bytecode *bc, unsigned char **bufp,
unsigned char *bufstart, void *d,
yasm_output_value_func output_value,
/*@unused@*/ yasm_output_reloc_func output_reloc)
{
bytecode_align *align = (bytecode_align *)bc->contents;
unsigned long len;
unsigned long boundary =
yasm_intnum_get_uint(yasm_expr_get_intnum(&align->boundary, 0));
if (boundary == 0)
return 0;
else {
unsigned long end = bc->offset;
if (bc->offset & (boundary-1))
end = (bc->offset & ~(boundary-1)) + boundary;
len = end - bc->offset;
if (len == 0)
return 0;
if (align->maxskip) {
unsigned long maxskip =
yasm_intnum_get_uint(yasm_expr_get_intnum(&align->maxskip, 0));
if (len > maxskip)
return 0;
}
}
if (align->fill) {
unsigned long v;
v = yasm_intnum_get_uint(yasm_expr_get_intnum(&align->fill, 0));
memset(*bufp, (int)v, len);
*bufp += len;
} else if (align->code_fill) {
unsigned long maxlen = 15;
while (!align->code_fill[maxlen] && maxlen>0)
maxlen--;
if (maxlen == 0) {
yasm_error_set(YASM_ERROR_GENERAL,
N_("could not find any code alignment size"));
return 1;
}
/* Fill with maximum code fill as much as possible */
while (len > maxlen) {
memcpy(*bufp, align->code_fill[maxlen], maxlen);
*bufp += maxlen;
len -= maxlen;
}
if (!align->code_fill[len]) {
yasm_error_set(YASM_ERROR_VALUE,
N_("invalid alignment size %d"), len);
return 1;
}
/* Handle rest of code fill */
memcpy(*bufp, align->code_fill[len], len);
*bufp += len;
} else {
/* Just fill with 0 */
memset(*bufp, 0, len);
*bufp += len;
}
return 0;
}
yasm_bytecode *
yasm_bc_create_align(yasm_expr *boundary, yasm_expr *fill,
yasm_expr *maxskip, const unsigned char **code_fill,
unsigned long line)
{
bytecode_align *align = yasm_xmalloc(sizeof(bytecode_align));
align->boundary = boundary;
align->fill = fill;
align->maxskip = maxskip;
align->code_fill = code_fill;
return yasm_bc_create_common(&bc_align_callback, align, line);
}
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