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macho64: fix alignment problems, add LC_DATA_IN_CODE

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Hopefully actually fix the issues with alignment this time.
Avoid a linear search of segments for each symbol emitted.
Issue an empty LC_DATA_IN_CODE command since that seems to be
expected.

With this, ffmpeg builds but still crashes on startup, which seems
very strange.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
H. Peter Anvin 2016-02-11 17:51:37 -08:00
parent ae01785d87
commit 5eebc6bc2b
1 changed files with 33 additions and 20 deletions
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53
output/outmac64.c
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@ -59,10 +59,11 @@
/* Mach-O in-file header structure sizes */
#define MACHO_HEADER64_SIZE (32)
#define MACHO_SEGCMD64_SIZE (72)
#define MACHO_SECTCMD64_SIZE (80)
#define MACHO_SECTCMD64_SIZE (80)
#define MACHO_SYMCMD_SIZE (24)
#define MACHO_NLIST64_SIZE (16)
#define MACHO_RELINFO64_SIZE (8)
#define MACHO_RELINFO64_SIZE (8)
#define MACHO_DATA_IN_CODE_CMD_SIZE (16)
/* Mach-O file header values */
#define MH_MAGIC_64 (0xfeedfacf)
@ -72,6 +73,7 @@
#define LC_SEGMENT_64 (0x19) /* segment load command */
#define LC_SYMTAB (0x2) /* symbol table load command */
#define LC_DATA_IN_CODE (0x29) /* data in code command */
#define VM_PROT_NONE (0x00)
#define VM_PROT_READ (0x01)
@ -94,6 +96,7 @@ struct section {
char segname[16]; /* segment this section will be in */
uint64_t addr; /* in-memory address (subject to alignment) */
uint64_t size; /* in-memory and -file size */
uint64_t offset; /* in-file offset */
uint32_t pad; /* padding bytes before section */
uint32_t nreloc; /* relocation entry count */
uint32_t flags; /* type and attributes (masked) */
@ -179,7 +182,7 @@ struct symbol {
#define NO_SECT 0 /* no section, invalid */
#define MAX_SECT 255 /* maximum number of sections */
static struct section *sects, **sectstail;
static struct section *sects, **sectstail, **sectstab;
static struct symbol *syms, **symstail;
static uint32_t nsyms;
@ -669,6 +672,7 @@ static int32_t macho_section(char *name, int pass, int *bits)
s->relocs = NULL;
s->align = -1;
s->pad = -1;
s->offset = -1;
xstrncpy(s->segname, sm->segname);
xstrncpy(s->sectname, sm->sectname);
@ -965,6 +969,7 @@ static void macho_layout_symbols (uint32_t *numsyms,
static void macho_calculate_sizes (void)
{
struct section *s;
int fi;
/* count sections and calculate in-memory and in-file offsets */
for (s = sects; s != NULL; s = s->next) {
@ -990,6 +995,7 @@ static void macho_calculate_sizes (void)
* perhaps aligning to pointer size would be better.
*/
s->pad = ALIGN(seg_filesize64, 4) - seg_filesize64;
s->offset = seg_filesize64 + s->pad;
seg_filesize64 += s->size + s->pad;
}
@ -1008,6 +1014,15 @@ static void macho_calculate_sizes (void)
++head_ncmds64;
head_sizeofcmds64 += MACHO_SYMCMD_SIZE;
}
++head_ncmds64; /* LC_DATA_IN_CODE */
head_sizeofcmds64 += MACHO_DATA_IN_CODE_CMD_SIZE;
/* Create a table of sections by file index to avoid linear search */
sectstab = nasm_malloc(seg_nsects64 + 1);
sectstab[0] = NULL;
for (s = sects, fi = 1; s != NULL; s = s->next, fi++)
sectstab[fi] = s;
}
/* Write out the header information for the file. */
@ -1035,8 +1050,9 @@ static uint32_t macho_write_segment (uint64_t offset)
fwriteint32_t(LC_SEGMENT_64, ofile); /* cmd == LC_SEGMENT_64 */
/* size of load command including section load commands */
fwriteint32_t(MACHO_SEGCMD64_SIZE + seg_nsects64 *
MACHO_SECTCMD64_SIZE, ofile);
fwriteint32_t(MACHO_SEGCMD64_SIZE +
seg_nsects64 * MACHO_SECTCMD64_SIZE,
ofile);
/* in an MH_OBJECT file all sections are in one unnamed (name
** all zeros) segment */
@ -1210,8 +1226,6 @@ static void macho_write_section (void)
static void macho_write_symtab (void)
{
struct symbol *sym;
struct section *s;
int64_t fi;
uint64_t i;
/* we don't need to pad here since MACHO_RELINFO_SIZE == 8 */
@ -1226,12 +1240,8 @@ static void macho_write_symtab (void)
/* Fix up the symbol value now that we know the final section
sizes. */
if (((sym->type & N_TYPE) == N_SECT) && (sym->sect != NO_SECT)) {
for (s = sects, fi = 1; s != NULL; s = s->next, fi++) {
if (fi == sym->sect) {
sym->value += s->addr;
break;
}
}
nasm_assert(sym->sect <= seg_nsects64);
sym->value += sectstab[sym->sect]->addr;
}
fwriteint64_t(sym->value, ofile); /* value (i.e. offset) */
@ -1248,9 +1258,8 @@ static void macho_write_symtab (void)
/* Fix up the symbol value now that we know the final section
sizes. */
if (((sym->type & N_TYPE) == N_SECT) && (sym->sect != NO_SECT)) {
for (s = sects, fi = 1;
s != NULL && fi < sym->sect; s = s->next, ++fi)
sym->value += s->size;
nasm_assert(sym->sect <= seg_nsects64);
sym->value += sectstab[sym->sect]->addr;
}
fwriteint64_t(sym->value, ofile); /* value (i.e. offset) */
@ -1265,9 +1274,8 @@ static void macho_write_symtab (void)
// Fix up the symbol value now that we know the final section sizes.
if (((sym->type & N_TYPE) == N_SECT) && (sym->sect != NO_SECT)) {
for (s = sects, fi = 1;
s != NULL && fi < sym->sect; s = s->next, ++fi)
sym->value += s->size;
nasm_assert(sym->sect <= seg_nsects64);
sym->value += sectstab[sym->sect]->addr;
}
fwriteint64_t(sym->value, ofile); // value (i.e. offset)
@ -1391,12 +1399,17 @@ static void macho_write (void)
fwriteint32_t(offset, ofile); /* symbol table offset */
fwriteint32_t(nsyms, ofile); /* number of symbol
** table entries */
offset += nsyms * MACHO_NLIST64_SIZE;
fwriteint32_t(offset, ofile); /* string table offset */
fwriteint32_t(strslen, ofile); /* string table size */
}
/* emit dummy data in code command */
fwriteint32_t(LC_DATA_IN_CODE, ofile);
fwriteint32_t(MACHO_DATA_IN_CODE_CMD_SIZE, ofile);
fwriteint32_t(offset, ofile);
fwriteint32_t(0, ofile); /* no actual DATA_IN_CODE */
/* emit section data */
if (seg_nsects64 > 0)
macho_write_section ();