OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR target/48108 (lto should be containerized in a single mach-o section on darwin)

Browse Source 
gcc:

	PR target/48108
	* config/darwin.c (top level): Amend comments concerning LTO output.
	(lto_section_num): New variable.  (darwin_lto_section_e): New GTY.
	(LTO_SECTS_SECTION, LTO_INDEX_SECTION): New.
	(LTO_NAMES_SECTION): Rename.
	(darwin_asm_named_section): Record LTO section counts and switches
	in a vec of darwin_lto_section_e.
	(darwin_file_start): Remove unused code.
	(darwin_file_end): Put an LTO section termination label.  Handle
	output of the wrapped LTO sections, index and names table.

libiberty:

	PR target/48108
	* simple-object-mach-o.c  (GNU_WRAPPER_SECTS, GNU_WRAPPER_INDEX,
	GNU_WRAPPER_NAMES): New macros.
	(simple_object_mach_o_segment): Handle wrapper scheme.
	(simple_object_mach_o_write_section_header): Allow the segment name
	to be supplied.
	(simple_object_mach_o_write_segment): Handle wrapper scheme.  Ensure
	that the top-level segment name in the load command is empty.
	(simple_object_mach_o_write_to_file): Determine the number of
	sections during segment output, use that in writing the header.

From-SVN: r180523
This commit is contained in:
Iain Sandoe 2011-10-26 12:37:59 +00:00
parent d44b26bdf4
commit b20577eae4
4 changed files with 581 additions and 137 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
gcc/ChangeLog
View File

@ -1,3 +1,16 @@
2011-10-14 Iain Sandoe <iains@gcc.gnu.org>
PR target/48108
* config/darwin.c (top level): Amend comments concerning LTO output.
(lto_section_num): New variable. (darwin_lto_section_e): New GTY.
(LTO_SECTS_SECTION, LTO_INDEX_SECTION): New.
(LTO_NAMES_SECTION): Rename.
(darwin_asm_named_section): Record LTO section counts and switches
in a vec of darwin_lto_section_e.
(darwin_file_start): Remove unused code.
(darwin_file_end): Put an LTO section termination label. Handle
output of the wrapped LTO sections, index and names table.
2011-10-26 Alan Modra <amodra@gmail.com>
* config/rs6000/rs6000.c (rs6000_make_savres_rtx): Delete unneeded

167
gcc/config/darwin.c
View File

@ -1753,19 +1753,51 @@ darwin_label_is_anonymous_local_objc_name (const char *name)
return (!strncmp ((const char *)p, "_OBJC_", 6));
}
/* LTO support for Mach-O. */
/* LTO support for Mach-O.
/* Section names for LTO sections. */
static unsigned int lto_section_names_offset = 0;
This version uses three mach-o sections to encapsulate the (unlimited
number of) lto sections.
/* This is the obstack which we use to allocate the many strings. */
static struct obstack lto_section_names_obstack;
__GNU_LTO, __lto_sections contains the concatented GNU LTO section data.
__GNU_LTO, __section_names contains the GNU LTO section names.
__GNU_LTO, __section_index contains an array of values that index these.
/* Segment name for LTO sections. */
Indexed thus:
<section offset from the start of __GNU_LTO, __lto_sections>,
<section length>
<name offset from the start of __GNU_LTO, __section_names,
<name length>.
At present, for both m32 and m64 mach-o files each of these fields is
represented by a uint32_t. This is because, AFAICT, a mach-o object
cannot exceed 4Gb because the section_64 offset field (see below) is 32bits.
uint32_t offset;
"offset An integer specifying the offset to this section in the file." */
/* Count lto section numbers. */
static unsigned int lto_section_num = 0;
/* A vector of information about LTO sections, at present, we only have
the name. TODO: see if we can get the data length somehow. */
typedef struct GTY (()) darwin_lto_section_e {
const char *sectname;
} darwin_lto_section_e ;
DEF_VEC_O(darwin_lto_section_e);
DEF_VEC_ALLOC_O(darwin_lto_section_e, gc);
static GTY (()) VEC (darwin_lto_section_e, gc) * lto_section_names;
/* Segment for LTO data. */
#define LTO_SEGMENT_NAME "__GNU_LTO"
/* Section name for LTO section names section. */
#define LTO_NAMES_SECTION "__section_names"
/* Section wrapper scheme (used here to wrap the unlimited number of LTO
sections into three Mach-O ones).
NOTE: These names MUST be kept in sync with those in
libiberty/simple-object-mach-o. */
#define LTO_SECTS_SECTION "__wrapper_sects"
#define LTO_NAMES_SECTION "__wrapper_names"
#define LTO_INDEX_SECTION "__wrapper_index"
/* File to temporarily store LTO data. This is appended to asm_out_file
in darwin_end_file. */
@ -1808,37 +1840,38 @@ darwin_asm_named_section (const char *name,
unsigned int flags,
tree decl ATTRIBUTE_UNUSED)
{
/* LTO sections go in a special segment __GNU_LTO. We want to replace the
section name with something we can use to represent arbitrary-length
names (section names in Mach-O are at most 16 characters long). */
/* LTO sections go in a special section that encapsulates the (unlimited)
number of GNU LTO sections within a single mach-o one. */
if (strncmp (name, LTO_SECTION_NAME_PREFIX,
strlen (LTO_SECTION_NAME_PREFIX)) == 0)
{
darwin_lto_section_e e;
/* We expect certain flags to be set... */
gcc_assert ((flags & (SECTION_DEBUG | SECTION_NAMED))
== (SECTION_DEBUG | SECTION_NAMED));
/* Add the section name to the things to output when we end the
current assembler output file.
This is all not very efficient, but that doesn't matter -- this
shouldn't be a hot path in the compiler... */
obstack_1grow (&lto_section_names_obstack, '\t');
obstack_grow (&lto_section_names_obstack, ".ascii ", 7);
obstack_1grow (&lto_section_names_obstack, '"');
obstack_grow (&lto_section_names_obstack, name, strlen (name));
obstack_grow (&lto_section_names_obstack, "\\0\"\n", 4);
/* Output the dummy section name. */
fprintf (asm_out_file, "\t# %s\n", name);
fprintf (asm_out_file, "\t.section %s,__%08X,regular,debug\n",
LTO_SEGMENT_NAME, lto_section_names_offset);
/* Update the offset for the next section name. Make sure we stay
within reasonable length. */
lto_section_names_offset += strlen (name) + 1;
gcc_assert (lto_section_names_offset > 0
&& lto_section_names_offset < ((unsigned) 1 << 31));
}
/* Switch to our combined section. */
fprintf (asm_out_file, "\t.section %s,%s,regular,debug\n",
LTO_SEGMENT_NAME, LTO_SECTS_SECTION);
/* Output a label for the start of this sub-section. */
fprintf (asm_out_file, "L_GNU_LTO%d:\t;# %s\n",
lto_section_num, name);
/* We have to jump through hoops to get the values of the intra-section
offsets... */
fprintf (asm_out_file, "\t.set L$gnu$lto$offs%d,L_GNU_LTO%d-L_GNU_LTO0\n",
lto_section_num, lto_section_num);
fprintf (asm_out_file,
"\t.set L$gnu$lto$size%d,L_GNU_LTO%d-L_GNU_LTO%d\n",
lto_section_num, lto_section_num+1, lto_section_num);
lto_section_num++;
e.sectname = xstrdup (name);
/* Keep the names, we'll need to make a table later.
TODO: check that we do not revisit sections, that would break
the assumption of how this is done. */
if (lto_section_names == NULL)
lto_section_names = VEC_alloc (darwin_lto_section_e, gc, 16);
VEC_safe_push (darwin_lto_section_e, gc, lto_section_names, &e);
}
else if (strncmp (name, "__DWARF,", 8) == 0)
darwin_asm_dwarf_section (name, flags, decl);
else
@ -2711,16 +2744,12 @@ darwin_asm_output_dwarf_offset (FILE *file, int size, const char * lab,
darwin_asm_output_dwarf_delta (file, size, lab, sname);
}
/* Called from the within the TARGET_ASM_FILE_START for each target.
Initialize the stuff we need for LTO long section names support. */
/* Called from the within the TARGET_ASM_FILE_START for each target. */
void
darwin_file_start (void)
{
/* We fill this obstack with the complete section text for the lto section
names to write in darwin_file_end. */
obstack_init (&lto_section_names_obstack);
lto_section_names_offset = 0;
/* Nothing to do. */
}
/* Called for the TARGET_ASM_FILE_END hook.
@ -2731,8 +2760,6 @@ darwin_file_start (void)
void
darwin_file_end (void)
{
const char *lto_section_names;
machopic_finish (asm_out_file);
if (strcmp (lang_hooks.name, "GNU C++") == 0)
{
@ -2762,6 +2789,13 @@ darwin_file_end (void)
lto_asm_txt = buf = (char *) xmalloc (n + 1);
while (fgets (lto_asm_txt, n, lto_asm_out_file))
fputs (lto_asm_txt, asm_out_file);
/* Put a termination label. */
fprintf (asm_out_file, "\t.section %s,%s,regular,debug\n",
LTO_SEGMENT_NAME, LTO_SECTS_SECTION);
fprintf (asm_out_file, "L_GNU_LTO%d:\t;# end of lto\n",
lto_section_num);
/* Make sure our termination label stays in this section. */
fputs ("\t.space\t1\n", asm_out_file);
}
/* Remove the temporary file. */
@ -2770,21 +2804,50 @@ darwin_file_end (void)
free (lto_asm_out_name);
}
/* Finish the LTO section names obstack. Don't output anything if
there are no recorded section names. */
obstack_1grow (&lto_section_names_obstack, '\0');
lto_section_names = XOBFINISH (&lto_section_names_obstack, const char *);
if (strlen (lto_section_names) > 0)
/* Output the names and indices. */
if (lto_section_names && VEC_length (darwin_lto_section_e, lto_section_names))
{
fprintf (asm_out_file,
"\t.section %s,%s,regular,debug\n",
int count;
darwin_lto_section_e *ref;
/* For now, we'll make the offsets 4 bytes and unaligned - we'll fix
the latter up ourselves. */
const char *op = integer_asm_op (4,0);
/* Emit the names. */
fprintf (asm_out_file, "\t.section %s,%s,regular,debug\n",
LTO_SEGMENT_NAME, LTO_NAMES_SECTION);
fprintf (asm_out_file,
"\t# Section names in %s are offsets into this table\n",
LTO_SEGMENT_NAME);
fprintf (asm_out_file, "%s\n", lto_section_names);
FOR_EACH_VEC_ELT (darwin_lto_section_e, lto_section_names, count, ref)
{
fprintf (asm_out_file, "L_GNU_LTO_NAME%d:\n", count);
/* We have to jump through hoops to get the values of the intra-section
offsets... */
fprintf (asm_out_file,
"\t.set L$gnu$lto$noff%d,L_GNU_LTO_NAME%d-L_GNU_LTO_NAME0\n",
count, count);
fprintf (asm_out_file,
"\t.set L$gnu$lto$nsiz%d,L_GNU_LTO_NAME%d-L_GNU_LTO_NAME%d\n",
count, count+1, count);
fprintf (asm_out_file, "\t.asciz\t\"%s\"\n", ref->sectname);
}
fprintf (asm_out_file, "L_GNU_LTO_NAME%d:\t;# end\n", lto_section_num);
/* make sure our termination label stays in this section. */
fputs ("\t.space\t1\n", asm_out_file);
/* Emit the Index. */
fprintf (asm_out_file, "\t.section %s,%s,regular,debug\n",
LTO_SEGMENT_NAME, LTO_INDEX_SECTION);
fputs ("\t.align\t2\n", asm_out_file);
fputs ("# Section offset, Section length, Name offset, Name length\n",
asm_out_file);
FOR_EACH_VEC_ELT (darwin_lto_section_e, lto_section_names, count, ref)
{
fprintf (asm_out_file, "%s L$gnu$lto$offs%d\t;# %s\n",
op, count, ref->sectname);
fprintf (asm_out_file, "%s L$gnu$lto$size%d\n", op, count);
fprintf (asm_out_file, "%s L$gnu$lto$noff%d\n", op, count);
fprintf (asm_out_file, "%s L$gnu$lto$nsiz%d\n", op, count);
}
}
obstack_free (&lto_section_names_obstack, NULL);
/* If we have section anchors, then we must prevent the linker from
re-arranging data. */

13
libiberty/ChangeLog
View File

@ -1,3 +1,16 @@
2011-10-26 Iain Sandoe <iains@gcc.gnu.org>
PR target/48108
* simple-object-mach-o.c (GNU_WRAPPER_SECTS, GNU_WRAPPER_INDEX,
GNU_WRAPPER_NAMES): New macros.
(simple_object_mach_o_segment): Handle wrapper scheme.
(simple_object_mach_o_write_section_header): Allow the segment name
to be supplied.
(simple_object_mach_o_write_segment): Handle wrapper scheme. Ensure
that the top-level segment name in the load command is empty.
(simple_object_mach_o_write_to_file): Determine the number of
sections during segment output, use that in writing the header.
2011-10-10 Ian Lance Taylor <iant@google.com>
PR c++/48665

525
libiberty/simple-object-mach-o.c
View File

@ -1,5 +1,5 @@
/* simple-object-mach-o.c -- routines to manipulate Mach-O object files.
Copyright 2010 Free Software Foundation, Inc.
Copyright 2010, 2011 Free Software Foundation, Inc.
Written by Ian Lance Taylor, Google.
This program is free software; you can redistribute it and/or modify it
@ -174,6 +174,15 @@ struct mach_o_section_64
#define GNU_SECTION_NAMES "__section_names"
/* A GNU-specific extension to wrap multiple sections using three
mach-o sections within a given segment. The section '__wrapper_sects'
is subdivided according to the index '__wrapper_index' and each sub
sect is named according to the names supplied in '__wrapper_names'. */
#define GNU_WRAPPER_SECTS "__wrapper_sects"
#define GNU_WRAPPER_INDEX "__wrapper_index"
#define GNU_WRAPPER_NAMES "__wrapper_names"
/* Private data for an simple_object_read. */
struct simple_object_mach_o_read
@ -214,7 +223,18 @@ struct simple_object_mach_o_attributes
unsigned int reserved;
};
/* See if we have a Mach-O file. */
/* See if we have a Mach-O MH_OBJECT file:
A standard MH_OBJECT (from as) will have three load commands:
0 - LC_SEGMENT/LC_SEGMENT64
1 - LC_SYMTAB
2 - LC_DYSYMTAB
The LC_SEGMENT/LC_SEGMENT64 will introduce a single anonymous segment
containing all the sections.
Files written by simple-object will have only the segment command
(no symbol tables). */
static void *
simple_object_mach_o_match (
@ -356,8 +376,29 @@ simple_object_mach_o_section_info (int is_big_endian, int is_32,
}
}
/* Handle a segment in a Mach-O file. Return 1 if we should continue,
0 if the caller should return. */
/* Handle a segment in a Mach-O Object file.
This will callback to the function pfn for each "section found" the meaning
of which depends on gnu extensions to mach-o:
If we find mach-o sections (with the segment name as specified) which also
contain: a 'sects' wrapper, an index, and a name table, we expand this into
as many sections as are specified in the index. In this case, there will
be a callback for each of these.
We will also allow an extension that permits long names (more than 16
characters) to be used with mach-o. In this case, the section name has
a specific format embedding an index into a name table, and the file must
contain such name table.
Return 1 if we should continue, 0 if the caller should return. */
#define SOMO_SECTS_PRESENT 0x01
#define SOMO_INDEX_PRESENT 0x02
#define SOMO_NAMES_PRESENT 0x04
#define SOMO_LONGN_PRESENT 0x08
#define SOMO_WRAPPING (SOMO_SECTS_PRESENT | SOMO_INDEX_PRESENT \
| SOMO_NAMES_PRESENT)
static int
simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
@ -378,9 +419,20 @@ simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
unsigned int nsects;
unsigned char *secdata;
unsigned int i;
unsigned int gnu_sections_found;
unsigned int strtab_index;
unsigned int index_index;
unsigned int nametab_index;
unsigned int sections_index;
char *strtab;
char *nametab;
unsigned char *index;
size_t strtab_size;
size_t nametab_size;
size_t index_size;
unsigned int n_wrapped_sects;
size_t wrapper_sect_size;
off_t wrapper_sect_offset;
fetch_32 = (omr->is_big_endian
? simple_object_fetch_big_32
@ -409,6 +461,8 @@ simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
nsects));
}
/* Fetch the section headers from the segment command. */
secdata = XNEWVEC (unsigned char, nsects * sechdrsize);
if (!simple_object_internal_read (sobj->descriptor, offset + seghdrsize,
secdata, nsects * sechdrsize, errmsg, err))
@ -417,9 +471,13 @@ simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
return 0;
}
/* Scan for a __section_names section. This is in effect a GNU
extension that permits section names longer than 16 chars. */
/* Scan for special sections that signal GNU extensions to the format. */
gnu_sections_found = 0;
index_index = nsects;
sections_index = nsects;
strtab_index = nsects;
nametab_index = nsects;
for (i = 0; i < nsects; ++i)
{
size_t nameoff;
@ -427,18 +485,103 @@ simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
nameoff = i * sechdrsize + segname_offset;
if (strcmp ((char *) secdata + nameoff, omr->segment_name) != 0)
continue;
nameoff = i * sechdrsize + sectname_offset;
if (strcmp ((char *) secdata + nameoff, GNU_SECTION_NAMES) == 0)
break;
if (strcmp ((char *) secdata + nameoff, GNU_WRAPPER_NAMES) == 0)
{
nametab_index = i;
gnu_sections_found |= SOMO_NAMES_PRESENT;
}
else if (strcmp ((char *) secdata + nameoff, GNU_WRAPPER_INDEX) == 0)
{
index_index = i;
gnu_sections_found |= SOMO_INDEX_PRESENT;
}
else if (strcmp ((char *) secdata + nameoff, GNU_WRAPPER_SECTS) == 0)
{
sections_index = i;
gnu_sections_found |= SOMO_SECTS_PRESENT;
}
else if (strcmp ((char *) secdata + nameoff, GNU_SECTION_NAMES) == 0)
{
strtab_index = i;
gnu_sections_found |= SOMO_LONGN_PRESENT;
}
}
strtab_index = i;
if (strtab_index >= nsects)
/* If any of the special wrapper section components is present, then
they all should be. */
if ((gnu_sections_found & SOMO_WRAPPING) != 0)
{
strtab = NULL;
strtab_size = 0;
off_t nametab_offset;
off_t index_offset;
if ((gnu_sections_found & SOMO_WRAPPING) != SOMO_WRAPPING)
{
*errmsg = "GNU Mach-o section wrapper: required section missing";
*err = 0; /* No useful errno. */
XDELETEVEC (secdata);
return 0;
}
/* Fetch the name table. */
simple_object_mach_o_section_info (omr->is_big_endian, is_32,
secdata + nametab_index * sechdrsize,
&nametab_offset, &nametab_size);
nametab = XNEWVEC (char, nametab_size);
if (!simple_object_internal_read (sobj->descriptor,
sobj->offset + nametab_offset,
(unsigned char *) nametab, nametab_size,
errmsg, err))
{
XDELETEVEC (nametab);
XDELETEVEC (secdata);
return 0;
}
/* Fetch the index. */
simple_object_mach_o_section_info (omr->is_big_endian, is_32,
secdata + index_index * sechdrsize,
&index_offset, &index_size);
index = XNEWVEC (unsigned char, index_size);
if (!simple_object_internal_read (sobj->descriptor,
sobj->offset + index_offset,
index, index_size,
errmsg, err))
{
XDELETEVEC (index);
XDELETEVEC (nametab);
XDELETEVEC (secdata);
return 0;
}
/* The index contains 4 unsigned ints per sub-section:
sub-section offset/length, sub-section name/length.
We fix this for both 32 and 64 bit mach-o for now, since
other fields limit the maximum size of an object to 4G. */
n_wrapped_sects = index_size / 16;
/* Get the parameters for the wrapper too. */
simple_object_mach_o_section_info (omr->is_big_endian, is_32,
secdata + sections_index * sechdrsize,
&wrapper_sect_offset,
&wrapper_sect_size);
}
else
{
index = NULL;
index_size = 0;
nametab = NULL;
nametab_size = 0;
n_wrapped_sects = 0;
}
/* If we have a long names section, fetch it. */
if ((gnu_sections_found & SOMO_LONGN_PRESENT) != 0)
{
off_t strtab_offset;
@ -452,52 +595,120 @@ simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
errmsg, err))
{
XDELETEVEC (strtab);
XDELETEVEC (index);
XDELETEVEC (nametab);
XDELETEVEC (secdata);
return 0;
}
}
else
{
strtab = NULL;
strtab_size = 0;
strtab_index = nsects;
}
/* Process the sections. */
for (i = 0; i < nsects; ++i)
{
const unsigned char *sechdr;
char namebuf[MACH_O_NAME_LEN + 1];
char namebuf[MACH_O_NAME_LEN * 2 + 2];
char *name;
off_t secoffset;
size_t secsize;
if (i == strtab_index)
continue;
int l;
sechdr = secdata + i * sechdrsize;
/* We've already processed the long section names. */
if ((gnu_sections_found & SOMO_LONGN_PRESENT) != 0
&& i == strtab_index)
continue;
/* We only act on the segment named. */
if (strcmp ((char *) sechdr + segname_offset, omr->segment_name) != 0)
continue;
memcpy (namebuf, sechdr + sectname_offset, MACH_O_NAME_LEN);
namebuf[MACH_O_NAME_LEN] = '\0';
/* Process sections associated with the wrapper. */
name = &namebuf[0];
if (strtab != NULL && name[0] == '_' && name[1] == '_')
if ((gnu_sections_found & SOMO_WRAPPING) != 0)
{
unsigned long stringoffset;
if (i == nametab_index || i == index_index)
continue;
if (sscanf (name + 2, "%08lX", &stringoffset) == 1)
if (i == sections_index)
{
if (stringoffset >= strtab_size)
unsigned int j;
for (j = 0; j < n_wrapped_sects; ++j)
{
*errmsg = "section name offset out of range";
*err = 0;
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 0;
}
unsigned int subsect_offset, subsect_length, name_offset;
subsect_offset = (*fetch_32) (index + 16 * j);
subsect_length = (*fetch_32) (index + 16 * j + 4);
name_offset = (*fetch_32) (index + 16 * j + 8);
/* We don't need the name_length yet. */
name = strtab + stringoffset;
secoffset = wrapper_sect_offset + subsect_offset;
secsize = subsect_length;
name = nametab + name_offset;
if (!(*pfn) (data, name, secoffset, secsize))
{
*errmsg = NULL;
*err = 0;
XDELETEVEC (index);
XDELETEVEC (nametab);
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 0;
}
}
continue;
}
}
if ((gnu_sections_found & SOMO_LONGN_PRESENT) != 0)
{
memcpy (namebuf, sechdr + sectname_offset, MACH_O_NAME_LEN);
namebuf[MACH_O_NAME_LEN] = '\0';
name = &namebuf[0];
if (strtab != NULL && name[0] == '_' && name[1] == '_')
{
unsigned long stringoffset;
if (sscanf (name + 2, "%08lX", &stringoffset) == 1)
{
if (stringoffset >= strtab_size)
{
*errmsg = "section name offset out of range";
*err = 0;
XDELETEVEC (index);
XDELETEVEC (nametab);
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 0;
}
name = strtab + stringoffset;
}
}
}
else
{
/* Otherwise, make a name like __segment,__section as per the
convention in mach-o asm. */
name = &namebuf[0];
memset (namebuf, 0, MACH_O_NAME_LEN * 2 + 2);
memcpy (namebuf, (char *) sechdr + segname_offset, MACH_O_NAME_LEN);
l = strlen (namebuf);
namebuf[l] = ',';
memcpy (namebuf + l + 1, (char *) sechdr + sectname_offset,
MACH_O_NAME_LEN);
}
simple_object_mach_o_section_info (omr->is_big_endian, is_32, sechdr,
&secoffset, &secsize);
@ -505,12 +716,16 @@ simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
{
*errmsg = NULL;
*err = 0;
XDELETEVEC (index);
XDELETEVEC (nametab);
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 0;
}
}
XDELETEVEC (index);
XDELETEVEC (nametab);
XDELETEVEC (strtab);
XDELETEVEC (secdata);
@ -724,9 +939,9 @@ static int
simple_object_mach_o_write_section_header (simple_object_write *sobj,
int descriptor,
size_t sechdr_offset,
const char *name, size_t secaddr,
size_t secsize, size_t offset,
unsigned int align,
const char *name, const char *segn,
size_t secaddr, size_t secsize,
size_t offset, unsigned int align,
const char **errmsg, int *err)
{
struct simple_object_mach_o_attributes *attrs =
@ -748,7 +963,7 @@ simple_object_mach_o_write_section_header (simple_object_write *sobj,
strncpy ((char *) hdr + offsetof (struct mach_o_section_32, sectname),
name, MACH_O_NAME_LEN);
strncpy ((char *) hdr + offsetof (struct mach_o_section_32, segname),
sobj->segment_name, MACH_O_NAME_LEN);
segn, MACH_O_NAME_LEN);
set_32 (hdr + offsetof (struct mach_o_section_32, addr), secaddr);
set_32 (hdr + offsetof (struct mach_o_section_32, size), secsize);
set_32 (hdr + offsetof (struct mach_o_section_32, offset), offset);
@ -773,7 +988,7 @@ simple_object_mach_o_write_section_header (simple_object_write *sobj,
strncpy ((char *) hdr + offsetof (struct mach_o_section_64, sectname),
name, MACH_O_NAME_LEN);
strncpy ((char *) hdr + offsetof (struct mach_o_section_64, segname),
sobj->segment_name, MACH_O_NAME_LEN);
segn, MACH_O_NAME_LEN);
set_64 (hdr + offsetof (struct mach_o_section_64, addr), secaddr);
set_64 (hdr + offsetof (struct mach_o_section_64, size), secsize);
set_32 (hdr + offsetof (struct mach_o_section_64, offset), offset);
@ -793,11 +1008,25 @@ simple_object_mach_o_write_section_header (simple_object_write *sobj,
sechdrsize, errmsg, err);
}
/* Write out the single segment and the sections of a Mach-O file. */
/* Write out the single (anonymous) segment containing the sections of a Mach-O
Object file.
As a GNU extension to mach-o, when the caller specifies a segment name in
sobj->segment_name, all the sections passed will be output under a single
mach-o section header. The caller's sections are indexed within this
'wrapper' section by a table stored in a second mach-o section. Finally,
arbitrary length section names are permitted by the extension and these are
stored in a table in a third mach-o section.
Note that this is only likely to make any sense for the __GNU_LTO segment
at present.
If the wrapper extension is not in force, we assume that the section name
is in the form __SEGMENT_NAME,__section_name as per Mach-O asm. */
static int
simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
size_t nsects, const char **errmsg,
size_t *nsects, const char **errmsg,
int *err)
{
struct simple_object_mach_o_attributes *attrs =
@ -814,6 +1043,10 @@ simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
simple_object_write_section *section;
unsigned char hdrbuf[sizeof (struct mach_o_segment_command_64)];
unsigned char *hdr;
size_t nsects_in;
unsigned int *index;
char *snames;
unsigned int sect;
set_32 = (attrs->is_big_endian
? simple_object_set_big_32
@ -834,19 +1067,62 @@ simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
sechdrsize = sizeof (struct mach_o_section_64);
}
sechdr_offset = hdrsize + seghdrsize;
cmdsize = seghdrsize + nsects * sechdrsize;
offset = hdrsize + cmdsize;
name_offset = 0;
secaddr = 0;
*nsects = nsects_in = 0;
/* Count the number of sections we start with. */
for (section = sobj->sections; section != NULL; section = section->next)
nsects_in++;
if (sobj->segment_name != NULL)
{
/* We will only write 3 sections: wrapped data, index and names. */
*nsects = 3;
/* The index has four entries per wrapped section:
Section Offset, length, Name offset, length.
Where the offsets are based at the start of the wrapper and name
sections respectively.
The values are stored as 32 bit int for both 32 and 64 bit mach-o
since the size of a mach-o MH_OBJECT cannot exceed 4G owing to
other constraints. */
index = XNEWVEC (unsigned int, nsects_in * 4);
/* We now need to figure out the size of the names section. This just
stores the names as null-terminated c strings, packed without any
alignment padding. */
for (section = sobj->sections, sect = 0; section != NULL;
section = section->next, sect++)
{
index[sect*4+2] = name_offset;
index[sect*4+3] = strlen (section->name) + 1;
name_offset += strlen (section->name) + 1;
}
snames = XNEWVEC (char, name_offset);
}
else
{
*nsects = nsects_in;
index = NULL;
snames = NULL;
}
sechdr_offset = hdrsize + seghdrsize;
cmdsize = seghdrsize + *nsects * sechdrsize;
offset = hdrsize + cmdsize;
secaddr = 0;
for (section = sobj->sections, sect = 0;
section != NULL; section = section->next, sect++)
{
size_t mask;
size_t new_offset;
size_t secsize;
struct simple_object_write_section_buffer *buffer;
char namebuf[MACH_O_NAME_LEN + 1];
mask = (1U << section->align) - 1;
new_offset = offset + mask;
@ -877,39 +1153,126 @@ simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
secsize += buffer->size;
}
snprintf (namebuf, sizeof namebuf, "__%08X", name_offset);
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset, namebuf,
secaddr, secsize, offset,
section->align,
errmsg, err))
return 0;
if (sobj->segment_name != NULL)
{
index[sect*4+0] = (unsigned int) offset;
index[sect*4+1] = secsize;
/* Stash the section name in our table. */
memcpy (snames + index[sect * 4 + 2], section->name,
index[sect * 4 + 3]);
}
else
{
char namebuf[MACH_O_NAME_LEN + 1];
char segnbuf[MACH_O_NAME_LEN + 1];
char *comma;
/* Try to extract segment,section from the input name. */
memset (namebuf, 0, sizeof namebuf);
memset (segnbuf, 0, sizeof segnbuf);
comma = strchr (section->name, ',');
if (comma != NULL)
{
int len = comma - section->name;
len = len > MACH_O_NAME_LEN ? MACH_O_NAME_LEN : len;
strncpy (namebuf, section->name, len);
strncpy (segnbuf, comma + 1, MACH_O_NAME_LEN);
}
else /* just try to copy the name, leave segment blank. */
strncpy (namebuf, section->name, MACH_O_NAME_LEN);
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset,
namebuf, segnbuf,
secaddr, secsize,
offset,
section->align,
errmsg, err))
return 0;
sechdr_offset += sechdrsize;
}
sechdr_offset += sechdrsize;
offset += secsize;
name_offset += strlen (section->name) + 1;
secaddr += secsize;
}
/* Write out the section names. */
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset,
GNU_SECTION_NAMES, secaddr,
name_offset, offset, 0,
errmsg, err))
return 0;
for (section = sobj->sections; section != NULL; section = section->next)
if (sobj->segment_name != NULL)
{
size_t namelen;
size_t secsize;
unsigned int i;
namelen = strlen (section->name) + 1;
if (!simple_object_internal_write (descriptor, offset,
(const unsigned char *) section->name,
namelen, errmsg, err))
/* Write the section header for the wrapper. */
/* Account for any initial aligment - which becomes the alignment for this
created section. */
secsize = (offset - index[0]);
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset,
GNU_WRAPPER_SECTS,
sobj->segment_name,
0 /*secaddr*/,
secsize, index[0],
sobj->sections->align,
errmsg, err))
return 0;
offset += namelen;
/* Subtract the wrapper section start from the begining of each sub
section. */
for (i = 1; i < nsects_in; ++i)
index[4 * i] -= index[0];
index[0] = 0;
sechdr_offset += sechdrsize;
/* Write out the section names.
... the header ...
name_offset contains the length of the section. It is not aligned. */
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset,
GNU_WRAPPER_NAMES,
sobj->segment_name,
0 /*secaddr*/,
name_offset,
offset,
0, errmsg, err))
return 0;
/* ... and the content.. */
if (!simple_object_internal_write (descriptor, offset,
(const unsigned char *) snames,
name_offset, errmsg, err))
return 0;
sechdr_offset += sechdrsize;
secaddr += name_offset;
offset += name_offset;
/* Now do the index, we'll align this to 4 bytes although the read code
will handle unaligned. */
offset += 3;
offset &= ~0x03;
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset,
GNU_WRAPPER_INDEX,
sobj->segment_name,
0 /*secaddr*/,
nsects_in * 16,
offset,
2, errmsg, err))
return 0;
/* ... and the content.. */
if (!simple_object_internal_write (descriptor, offset,
(const unsigned char *) index,
nsects_in*16, errmsg, err))
return 0;
XDELETEVEC (index);
XDELETEVEC (snames);
}
/* Write out the segment header. */
@ -923,9 +1286,8 @@ simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
MACH_O_LC_SEGMENT);
set_32 (hdr + offsetof (struct mach_o_segment_command_32, cmdsize),
cmdsize);
strncpy (((char *) hdr
+ offsetof (struct mach_o_segment_command_32, segname)),
sobj->segment_name, MACH_O_NAME_LEN);
/* MH_OBJECTS have a single, anonymous, segment - so the segment name
is left empty. */
/* vmaddr left as zero. */
/* vmsize left as zero. */
set_32 (hdr + offsetof (struct mach_o_segment_command_32, fileoff),
@ -935,7 +1297,7 @@ simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
/* maxprot left as zero. */
/* initprot left as zero. */
set_32 (hdr + offsetof (struct mach_o_segment_command_32, nsects),
nsects);
*nsects);
/* flags left as zero. */
}
else
@ -951,9 +1313,8 @@ simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
MACH_O_LC_SEGMENT);
set_32 (hdr + offsetof (struct mach_o_segment_command_64, cmdsize),
cmdsize);
strncpy (((char *) hdr
+ offsetof (struct mach_o_segment_command_64, segname)),
sobj->segment_name, MACH_O_NAME_LEN);
/* MH_OBJECTS have a single, anonymous, segment - so the segment name
is left empty. */
/* vmaddr left as zero. */
/* vmsize left as zero. */
set_64 (hdr + offsetof (struct mach_o_segment_command_64, fileoff),
@ -963,7 +1324,7 @@ simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
/* maxprot left as zero. */
/* initprot left as zero. */
set_32 (hdr + offsetof (struct mach_o_segment_command_64, nsects),
nsects);
*nsects);
/* flags left as zero. */
#endif
}
@ -978,23 +1339,17 @@ static const char *
simple_object_mach_o_write_to_file (simple_object_write *sobj, int descriptor,
int *err)
{
size_t nsects;
simple_object_write_section *section;
size_t nsects = 0;
const char *errmsg;
/* Start at 1 for symbol_names section. */
nsects = 1;
for (section = sobj->sections; section != NULL; section = section->next)
++nsects;
if (!simple_object_mach_o_write_segment (sobj, descriptor, &nsects,
&errmsg, err))
return errmsg;
if (!simple_object_mach_o_write_header (sobj, descriptor, nsects,
&errmsg, err))
return errmsg;
if (!simple_object_mach_o_write_segment (sobj, descriptor, nsects,
&errmsg, err))
return errmsg;
return NULL;
}