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outmacho: support the "subsections_via_symbols" directive

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The "subsection_via_symbols" directive simply sets a flag in the
Mach-O file header.

Requested in BR 3392367.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
H. Peter Anvin 2017-03-07 22:43:00 -08:00
parent e562b70cea
commit 8e1cb8e594
4 changed files with 38 additions and 7 deletions
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3
asm/directiv.dat
View file

@ -1,6 +1,6 @@
;; --------------------------------------------------------------------------
;;
;; Copyright 1996-2016 The NASM Authors - All Rights Reserved
;; Copyright 1996-2017 The NASM Authors - All Rights Reserved
;; See the file AUTHORS included with the NASM distribution for
;; the specific copyright holders.
;;
@ -62,3 +62,4 @@ org ; outbin
osabi ; outelf
safeseh ; outcoff
uppercase ; outieee, outobj
subsections_via_symbols ; outmacho

2
asm/directiv.pl
View file

@ -54,7 +54,7 @@ open(DD, "< ${directives_dat}\0")
or die "$0: cannot open: ${directives_dat}: $!\n";
while (defined($line = <DD>)) {
chomp $line;
if ($line =~ /^\s*([[:alnum:]]+)\s*(|[\;\#].*)$/) {
if ($line =~ /^\s*([[:alnum:]_]+)\s*(|[\;\#].*)$/) {
push(@directives, $1);
}
}

33
output/outmacho.c
View file

@ -1,6 +1,6 @@
/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2016 The NASM Authors - All Rights Reserved
* Copyright 1996-2017 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
@ -75,6 +75,9 @@
#define CPU_SUBTYPE_I386_ALL 3 /* all-x86 compatible */
#define MH_OBJECT 0x1 /* object file */
/* Mach-O header flags */
#define MH_SUBSECTIONS_VIA_SYMBOLS 0x2000
/* Mach-O load commands */
#define LC_SEGMENT 0x1 /* 32-bit segment load cmd */
#define LC_SEGMENT_64 0x19 /* 64-bit segment load cmd */
@ -281,6 +284,7 @@ static uint32_t strslen;
a structure or as function arguments. */
static uint32_t head_ncmds = 0;
static uint32_t head_sizeofcmds = 0;
static uint32_t head_flags = 0;
static uint64_t seg_filesize = 0;
static uint64_t seg_vmsize = 0;
static uint32_t seg_nsects = 0;
@ -1162,7 +1166,7 @@ static void macho_write_header (void)
fwriteint32_t(MH_OBJECT, ofile); /* Mach-O file type */
fwriteint32_t(head_ncmds, ofile); /* number of load commands */
fwriteint32_t(head_sizeofcmds, ofile); /* size of load commands */
fwriteint32_t(0, ofile); /* no flags */
fwriteint32_t(head_flags, ofile); /* flags, if any */
fwritezero(fmt.header_size - 7*4, ofile); /* reserved fields */
}
@ -1594,6 +1598,27 @@ static void macho_cleanup(void)
nasm_free(sectstab);
}
/*
* Mach-O-specific directives
*/
static enum directive_result
macho_directive(enum directives directive, char *value, int pass)
{
switch (directive) {
case D_SUBSECTIONS_VIA_SYMBOLS:
if (*value)
return DIRR_BADPARAM;
if (pass == 2)
head_flags |= MH_SUBSECTIONS_VIA_SYMBOLS;
return DIRR_OK;
default:
return DIRR_UNKNOWN; /* Not a Mach-O directive */
}
}
#ifdef OF_MACHO32
static const struct macho_fmt macho32_fmt = {
4,
@ -1634,7 +1659,7 @@ const struct ofmt of_macho32 = {
macho_section,
macho_sectalign,
macho_segbase,
null_directive,
macho_directive,
macho_filename,
macho_cleanup,
NULL /* pragma list */
@ -1683,7 +1708,7 @@ const struct ofmt of_macho64 = {
macho_section,
macho_sectalign,
macho_segbase,
null_directive,
macho_directive,
macho_filename,
macho_cleanup,
NULL /* pragma list */

7
output/outmacho.mac
View file

@ -1,6 +1,6 @@
;; --------------------------------------------------------------------------
;;
;; Copyright 1996-2009 The NASM Authors - All Rights Reserved
;; Copyright 1996-2017 The NASM Authors - All Rights Reserved
;; See the file AUTHORS included with the NASM distribution for
;; the specific copyright holders.
;;
@ -35,3 +35,8 @@ OUT: macho macho32 macho64
%define __SECT__ [section .text]
%macro __NASM_CDecl__ 1
%endmacro
; This directive sets the MH_SUBSECTION_VIA_SYMBOLS header flag
%macro subsection_via_symbols 0
[%?]
%endmacro