github-repos/tinycc
1
0
Fork 0
mirror of https://github.com/mirror/tinycc.git synced 2024-12-28 04:00:06 +08:00
Code Issues Packages Projects Releases Wiki Activity
84c3fecf5e
tinycc/tccmacho.c

831 lines
31 KiB
C
Raw Normal View History

macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
/*
* Mach-O file handling for TCC
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "tcc.h"
struct mach_header {
uint32_t magic; /* mach magic number identifier */
int cputype; /* cpu specifier */
int cpusubtype; /* machine specifier */
uint32_t filetype; /* type of file */
uint32_t ncmds; /* number of load commands */
uint32_t sizeofcmds; /* the size of all the load commands */
uint32_t flags; /* flags */
};
struct mach_header_64 {
struct mach_header mh;
uint32_t reserved; /* reserved, pad to 64bit */
};
/* Constant for the magic field of the mach_header (32-bit architectures) */
#define MH_MAGIC 0xfeedface /* the mach magic number */
#define MH_CIGAM 0xcefaedfe /* NXSwapInt(MH_MAGIC) */
#define MH_MAGIC_64 0xfeedfacf /* the 64-bit mach magic number */
#define MH_CIGAM_64 0xcffaedfe /* NXSwapInt(MH_MAGIC_64) */
struct load_command {
uint32_t cmd; /* type of load command */
uint32_t cmdsize; /* total size of command in bytes */
};
typedef int vm_prot_t;
struct segment_command { /* for 32-bit architectures */
uint32_t cmd; /* LC_SEGMENT */
uint32_t cmdsize; /* includes sizeof section structs */
char segname[16]; /* segment name */
uint32_t vmaddr; /* memory address of this segment */
uint32_t vmsize; /* memory size of this segment */
uint32_t fileoff; /* file offset of this segment */
uint32_t filesize; /* amount to map from the file */
vm_prot_t maxprot; /* maximum VM protection */
vm_prot_t initprot; /* initial VM protection */
uint32_t nsects; /* number of sections in segment */
uint32_t flags; /* flags */
};
struct segment_command_64 { /* for 64-bit architectures */
uint32_t cmd; /* LC_SEGMENT_64 */
uint32_t cmdsize; /* includes sizeof section_64 structs */
char segname[16]; /* segment name */
uint64_t vmaddr; /* memory address of this segment */
uint64_t vmsize; /* memory size of this segment */
uint64_t fileoff; /* file offset of this segment */
uint64_t filesize; /* amount to map from the file */
vm_prot_t maxprot; /* maximum VM protection */
vm_prot_t initprot; /* initial VM protection */
uint32_t nsects; /* number of sections in segment */
uint32_t flags; /* flags */
};
struct section { /* for 32-bit architectures */
char sectname[16]; /* name of this section */
char segname[16]; /* segment this section goes in */
uint32_t addr; /* memory address of this section */
uint32_t size; /* size in bytes of this section */
uint32_t offset; /* file offset of this section */
uint32_t align; /* section alignment (power of 2) */
uint32_t reloff; /* file offset of relocation entries */
uint32_t nreloc; /* number of relocation entries */
uint32_t flags; /* flags (section type and attributes)*/
uint32_t reserved1; /* reserved (for offset or index) */
uint32_t reserved2; /* reserved (for count or sizeof) */
};
struct section_64 { /* for 64-bit architectures */
char sectname[16]; /* name of this section */
char segname[16]; /* segment this section goes in */
uint64_t addr; /* memory address of this section */
uint64_t size; /* size in bytes of this section */
uint32_t offset; /* file offset of this section */
uint32_t align; /* section alignment (power of 2) */
uint32_t reloff; /* file offset of relocation entries */
uint32_t nreloc; /* number of relocation entries */
uint32_t flags; /* flags (section type and attributes)*/
uint32_t reserved1; /* reserved (for offset or index) */
uint32_t reserved2; /* reserved (for count or sizeof) */
uint32_t reserved3; /* reserved */
};
typedef uint32_t lc_str;
struct dylib_command {
uint32_t cmd; /* LC_ID_DYLIB, LC_LOAD_{,WEAK_}DYLIB,
LC_REEXPORT_DYLIB */
uint32_t cmdsize; /* includes pathname string */
lc_str name; /* library's path name */
uint32_t timestamp; /* library's build time stamp */
uint32_t current_version; /* library's current version number */
uint32_t compatibility_version; /* library's compatibility vers number*/
};
struct dylinker_command {
uint32_t cmd; /* LC_ID_DYLINKER, LC_LOAD_DYLINKER or
LC_DYLD_ENVIRONMENT */
uint32_t cmdsize; /* includes pathname string */
lc_str name; /* dynamic linker's path name */
};
struct symtab_command {
uint32_t cmd; /* LC_SYMTAB */
uint32_t cmdsize; /* sizeof(struct symtab_command) */
uint32_t symoff; /* symbol table offset */
uint32_t nsyms; /* number of symbol table entries */
uint32_t stroff; /* string table offset */
uint32_t strsize; /* string table size in bytes */
};
struct dysymtab_command {
uint32_t cmd; /* LC_DYSYMTAB */
uint32_t cmdsize; /* sizeof(struct dysymtab_command) */
uint32_t ilocalsym; /* index to local symbols */
uint32_t nlocalsym; /* number of local symbols */
uint32_t iextdefsym;/* index to externally defined symbols */
uint32_t nextdefsym;/* number of externally defined symbols */
uint32_t iundefsym; /* index to undefined symbols */
uint32_t nundefsym; /* number of undefined symbols */
uint32_t tocoff; /* file offset to table of contents */
uint32_t ntoc; /* number of entries in table of contents */
uint32_t modtaboff; /* file offset to module table */
uint32_t nmodtab; /* number of module table entries */
uint32_t extrefsymoff; /* offset to referenced symbol table */
uint32_t nextrefsyms; /* number of referenced symbol table entries */
uint32_t indirectsymoff; /* file offset to the indirect symbol table */
uint32_t nindirectsyms; /* number of indirect symbol table entries */
uint32_t extreloff; /* offset to external relocation entries */
uint32_t nextrel; /* number of external relocation entries */
uint32_t locreloff; /* offset to local relocation entries */
uint32_t nlocrel; /* number of local relocation entries */
};
struct linkedit_data_command {
uint32_t cmd; /* LC_CODE_SIGNATURE, LC_SEGMENT_SPLIT_INFO,
LC_FUNCTION_STARTS, LC_DATA_IN_CODE,
LC_DYLIB_CODE_SIGN_DRS or
LC_LINKER_OPTIMIZATION_HINT. */
uint32_t cmdsize; /* sizeof(struct linkedit_data_command) */
uint32_t dataoff; /* file offset of data in __LINKEDIT segment */
uint32_t datasize; /* file size of data in __LINKEDIT segment */
};
struct entry_point_command {
uint32_t cmd; /* LC_MAIN only used in MH_EXECUTE filetypes */
uint32_t cmdsize; /* 24 */
uint64_t entryoff; /* file (__TEXT) offset of main() */
uint64_t stacksize;/* if not zero, initial stack size */
};
enum skind {
sk_unknown = 0,
sk_discard,
sk_text,
sk_stubs,
sk_ro_data,
sk_uw_info,
sk_nl_ptr, // non-lazy pointers, aka GOT
sk_la_ptr, // lazy pointers
sk_rw_data,
sk_bss,
sk_linkedit,
sk_last
};
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
struct nlist_64 {
uint32_t n_strx; /* index into the string table */
uint8_t n_type; /* type flag, see below */
uint8_t n_sect; /* section number or NO_SECT */
uint16_t n_desc; /* see <mach-o/stab.h> */
uint64_t n_value; /* value of this symbol (or stab offset) */
};
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
struct macho {
struct mach_header_64 mh;
struct segment_command_64 *seg[4];
int nseg;
struct load_command **lc;
int nlc;
struct entry_point_command ep;
struct {
Section *s;
int machosect;
} sk_to_sect[sk_last];
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
int *elfsectomacho;
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
int *e2msym;
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
Section *linkedit, *symtab, *strtab, *wdata, *indirsyms, *stubs;
int stubsym;
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
uint32_t ilocal, iextdef, iundef;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
};
#define SHT_LINKEDIT (SHT_LOOS + 42)
macos: handle undefined symbols a bit at least data symbols coming from dylibs can be used now, as in the below. Note in the example that optind is defined in libc (really in libsystem_c.dylib, reexported from libSystem.B.dylib): static int loc; extern int _optind; int _start(void) { _optind = 0; loc = 42 + _optind; return loc - 42; }
2020-05-17 11:36:00 +08:00
#define SHN_FROMDLL (SHN_LOOS + 2) /* Symbol is undefined, comes from a DLL */
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
#define LC_REQ_DYLD 0x80000000
#define LC_SYMTAB 0x2
#define LC_DYSYMTAB 0xb
#define LC_LOAD_DYLIB 0xc
#define LC_LOAD_DYLINKER 0xe
#define LC_MAIN (0x28|LC_REQ_DYLD)
/* Hack for now, 46_grep.c needs fopen, but due to aliasing games
in darwin headers it's searching for _fopen also via dlsym. */
FILE *_fopen(const char*, const char*);
FILE *_fopen(const char * filename, const char *mode)
{
return fopen(filename, mode);
}
static struct segment_command_64 * add_segment(struct macho *mo, char *name)
{
struct segment_command_64 *sc = tcc_mallocz(sizeof *sc);
strncpy(sc->segname, name, 16);
sc->cmd = 0x19; // LC_SEGMENT_64
sc->cmdsize = sizeof(*sc);
mo->seg[mo->nseg++] = sc;
return sc;
}
static int add_section(struct macho *mo, struct segment_command_64 **_seg, char *name)
{
struct segment_command_64 *seg = *_seg;
int ret = seg->nsects;
struct section_64 *sec;
seg->nsects++;
seg->cmdsize += sizeof(*sec);
seg = tcc_realloc(seg, sizeof(*seg) + seg->nsects * sizeof(*sec));
sec = (struct section_64*)((char*)seg + sizeof(*seg)) + ret;
memset(sec, 0, sizeof(*sec));
strncpy(sec->sectname, name, 16);
strncpy(sec->segname, seg->segname, 16);
*_seg = seg;
return ret;
}
static struct section_64 *get_section(struct segment_command_64 *seg, int i)
{
struct section_64 *sec;
sec = (struct section_64*)((char*)seg + sizeof(*seg)) + i;
return sec;
}
static void * add_lc(struct macho *mo, void *lc)
{
mo->lc = tcc_realloc(mo->lc, sizeof(mo->lc[0]) * (mo->nlc + 1));
mo->lc[mo->nlc++] = lc;
return lc;
}
static void * add_dylib(struct macho *mo, char *name)
{
struct dylib_command *lc;
int sz = (sizeof(*lc) + strlen(name) + 1 + 7) & -8;
lc = tcc_mallocz(sz);
lc->cmd = LC_LOAD_DYLIB;
lc->cmdsize = sz;
lc->name = sizeof(*lc);
strcpy((char*)lc + lc->name, name);
lc->timestamp = 2;
lc->current_version = 1 << 16;
lc->compatibility_version = 1 << 16;
return add_lc(mo, lc);
}
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
static void check_relocs(TCCState *s1, struct macho *mo)
{
Section *s;
ElfW_Rel *rel;
ElfW(Sym) *sym;
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
int i, type, gotplt_entry, sym_index, for_code;
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
struct sym_attr *attr;
s1->got = new_section(s1, ".got", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
mo->indirsyms = new_section(s1, "LEINDIR", SHT_LINKEDIT, SHF_ALLOC | SHF_WRITE);
for (i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (s->sh_type != SHT_RELX)
continue;
for_each_elem(s, 0, rel, ElfW_Rel) {
type = ELFW(R_TYPE)(rel->r_info);
gotplt_entry = gotplt_entry_type(type);
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
for_code = code_reloc(type);
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
/* We generate a non-lazy pointer for used undefined symbols
and for defined symbols that must have a place for their
address due to codegen (i.e. a reloc requiring a got slot). */
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
if (sym->st_shndx == SHN_UNDEF
|| gotplt_entry == ALWAYS_GOTPLT_ENTRY) {
attr = get_sym_attr(s1, sym_index, 1);
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
if (!attr->dyn_index) {
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
uint32_t *pi = section_ptr_add(mo->indirsyms, sizeof(*pi));
attr->got_offset = s1->got->data_offset;
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
attr->plt_offset = -1;
attr->dyn_index = 1; /* used as flag */
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
section_ptr_add(s1->got, PTR_SIZE);
macos: Fix GOT access to local defined symbols if a GOT slot is required (due to codegen, indicated by presence of some relocation types), then it needs to contain the address of the wanted symbol, also when it's local and defined, i.e. not overridable. For simplicity we use a GOT slot for that as well (other storage would require rewriting relocs and symbols, as resolving of GOT relocs is hardwired to be based on s1->got). But that means we need to fill in its indirect symbol mapping slot as well, for which Mach-O provides a mean to say "not symbol based, resolved locally". So this fixes this testcase: static int loc; int _start(void) { loc = 42; return loc - 42; } (where our codegen currently uses a GOT-based access for the write by accident)
2020-05-17 10:39:40 +08:00
if (ELFW(ST_BIND)(sym->st_info) == STB_LOCAL) {
if (sym->st_shndx == SHN_UNDEF)
tcc_error("undefined local symbol???");
*pi = 0x80000000; /* INDIRECT_SYMBOL_LOCAL */
/* The pointer slot we generated must point to the
symbol, whose address is only known after layout,
so register a simply relocation for that. */
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
put_elf_reloc(s1->symtab, s1->got, attr->got_offset,
R_DATA_PTR, sym_index);
macos: Fix GOT access to local defined symbols if a GOT slot is required (due to codegen, indicated by presence of some relocation types), then it needs to contain the address of the wanted symbol, also when it's local and defined, i.e. not overridable. For simplicity we use a GOT slot for that as well (other storage would require rewriting relocs and symbols, as resolving of GOT relocs is hardwired to be based on s1->got). But that means we need to fill in its indirect symbol mapping slot as well, for which Mach-O provides a mean to say "not symbol based, resolved locally". So this fixes this testcase: static int loc; int _start(void) { loc = 42; return loc - 42; } (where our codegen currently uses a GOT-based access for the write by accident)
2020-05-17 10:39:40 +08:00
} else
*pi = mo->e2msym[sym_index];
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
}
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
if (for_code) {
if (attr->plt_offset == -1) {
uint8_t *jmp;
attr->plt_offset = mo->stubs->data_offset;
jmp = section_ptr_add(mo->stubs, 6);
jmp[0] = 0xff; /* jmpq *ofs(%rip) */
jmp[1] = 0x25;
put_elf_reloc(s1->symtab, mo->stubs,
attr->plt_offset + 2,
R_X86_64_GOTPCREL, sym_index);
}
rel->r_info = ELFW(R_INFO)(mo->stubsym, type);
rel->r_addend += attr->plt_offset;
}
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
}
}
}
}
static int check_symbols(TCCState *s1, struct macho *mo)
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
{
int sym_index, sym_end;
int ret = 0;
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
mo->ilocal = mo->iextdef = mo->iundef = -1;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
sym_end = symtab_section->data_offset / sizeof(ElfW(Sym));
for (sym_index = 1; sym_index < sym_end; ++sym_index) {
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
int elf_index = ((struct nlist_64 *)mo->symtab->data + sym_index - 1)->n_value;
ElfW(Sym) *sym = (ElfW(Sym) *)symtab_section->data + elf_index;
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
const char *name = (char*)symtab_section->link->data + sym->st_name;
unsigned type = ELFW(ST_TYPE)(sym->st_info);
unsigned bind = ELFW(ST_BIND)(sym->st_info);
unsigned vis = ELFW(ST_VISIBILITY)(sym->st_other);
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
printf("%4d (%4d): %09llx %4d %4d %4d %3d %s\n",
sym_index, elf_index, sym->st_value,
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
type, bind, vis, sym->st_shndx, name);
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
if (bind == STB_LOCAL) {
if (mo->ilocal == -1)
mo->ilocal = sym_index - 1;
if (mo->iextdef != -1 || mo->iundef != -1)
tcc_error("local syms after global ones");
} else if (sym->st_shndx != SHN_UNDEF) {
if (mo->iextdef == -1)
mo->iextdef = sym_index - 1;
if (mo->iundef != -1)
tcc_error("external defined symbol after undefined");
} else if (sym->st_shndx == SHN_UNDEF) {
if (mo->iundef == -1)
mo->iundef = sym_index - 1;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
if (ELFW(ST_BIND)(sym->st_info) == STB_WEAK)
continue;
macos: handle undefined symbols a bit at least data symbols coming from dylibs can be used now, as in the below. Note in the example that optind is defined in libc (really in libsystem_c.dylib, reexported from libSystem.B.dylib): static int loc; extern int _optind; int _start(void) { _optind = 0; loc = 42 + _optind; return loc - 42; }
2020-05-17 11:36:00 +08:00
if (get_sym_attr(s1, elf_index, 0)) {
/* Mark the symbol as coming from a dylib so that
relocate_syms doesn't complain. Normally we would have
checked that any dylib in fact exports this one, and listed
those in s1->dynsymtab, which would cause us to enter this
symbol into s1->dynsym, which is checked by relocate_syms.
But for now we fake this and regard all undefined as
coming from a dylib, and we don't use the dynsymtab/dynsym
scheme. */
sym->st_shndx = SHN_FROMDLL;
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
continue;
macos: handle undefined symbols a bit at least data symbols coming from dylibs can be used now, as in the below. Note in the example that optind is defined in libc (really in libsystem_c.dylib, reexported from libSystem.B.dylib): static int loc; extern int _optind; int _start(void) { _optind = 0; loc = 42 + _optind; return loc - 42; }
2020-05-17 11:36:00 +08:00
}
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
tcc_error_noabort("undefined symbol '%s'", name);
ret = -1;
}
}
return ret;
}
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
static void convert_symbol(TCCState *s1, struct macho *mo, struct nlist_64 *pn)
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
{
struct nlist_64 n = *pn;
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
ElfSym *sym = (ElfW(Sym) *)symtab_section->data + pn->n_value;
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
const char *name = (char*)symtab_section->link->data + sym->st_name;
switch(ELFW(ST_TYPE)(sym->st_info)) {
case STT_NOTYPE:
case STT_OBJECT:
case STT_FUNC:
n.n_type = 0xe; /* default type is N_SECT */
break;
case STT_FILE:
n.n_type = 2; /* N_ABS */
break;
default:
tcc_error("unhandled ELF symbol type %d %s",
ELFW(ST_TYPE)(sym->st_info), name);
}
if (sym->st_shndx == SHN_UNDEF)
macos: handle undefined symbols a bit at least data symbols coming from dylibs can be used now, as in the below. Note in the example that optind is defined in libc (really in libsystem_c.dylib, reexported from libSystem.B.dylib): static int loc; extern int _optind; int _start(void) { _optind = 0; loc = 42 + _optind; return loc - 42; }
2020-05-17 11:36:00 +08:00
tcc_error("should have been rewritten to SHN_FROMDLL");
else if (sym->st_shndx == SHN_FROMDLL)
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
n.n_type = 0 /* N_UNDF */, n.n_sect = 0;
else if (sym->st_shndx == SHN_ABS)
n.n_type = 2 /* N_ABS */, n.n_sect = 0;
else if (sym->st_shndx >= SHN_LORESERVE)
tcc_error("unhandled ELF symbol section %d %s", sym->st_shndx, name);
else if (!mo->elfsectomacho[sym->st_shndx])
tcc_error("ELF section %d not mapped into Mach-O for symbol %s",
sym->st_shndx, name);
else
n.n_sect = mo->elfsectomacho[sym->st_shndx];
if (ELFW(ST_BIND)(sym->st_info) == STB_GLOBAL)
n.n_type |= 1; /* N_EXT */
else if (ELFW(ST_BIND)(sym->st_info) == STB_WEAK)
tcc_error("weak symbol %s unhandled", name);
n.n_strx = pn->n_strx;
n.n_value = sym->st_value;
*pn = n;
}
static void convert_symbols(TCCState *s1, struct macho *mo)
{
int sym_index, sym_end;
struct nlist_64 *pn = (struct nlist_64 *)mo->symtab->data;
sym_end = symtab_section->data_offset / sizeof(ElfW(Sym));
for (sym_index = 1; sym_index < sym_end; ++sym_index) {
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
convert_symbol(s1, mo, pn + sym_index - 1);
}
}
static int machosymcmp(const void *_a, const void *_b)
{
TCCState *s1 = tcc_state;
int ea = ((struct nlist_64 *)_a)->n_value;
int eb = ((struct nlist_64 *)_b)->n_value;
ElfSym *sa = (ElfSym *)symtab_section->data + ea;
ElfSym *sb = (ElfSym *)symtab_section->data + eb;
int r;
r = (ELFW(ST_BIND)(sb->st_info) == STB_LOCAL)
- (ELFW(ST_BIND)(sa->st_info) == STB_LOCAL);
if (r)
return r;
macos: handle undefined symbols a bit at least data symbols coming from dylibs can be used now, as in the below. Note in the example that optind is defined in libc (really in libsystem_c.dylib, reexported from libSystem.B.dylib): static int loc; extern int _optind; int _start(void) { _optind = 0; loc = 42 + _optind; return loc - 42; }
2020-05-17 11:36:00 +08:00
r = (sa->st_shndx == SHN_UNDEF) - (sb->st_shndx == SHN_UNDEF);
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
if (r)
return r;
if (ELFW(ST_BIND)(sa->st_info) != STB_LOCAL) {
const char * na = (char*)symtab_section->link->data + sa->st_name;
const char * nb = (char*)symtab_section->link->data + sb->st_name;
r = strcmp(na, nb);
if (r)
return r;
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
}
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
return ea - eb;
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
}
static void create_symtab(TCCState *s1, struct macho *mo)
{
int sym_index, sym_end;
struct nlist_64 *pn;
macos: Support external functions these are resolved non-lazy for now. We only need to generate the jump stub (using the GOT slot that will be initialized due to the non-lazy pointer marking, like with data symbols). On x86-64 we don't even need special marking of these stubs (with S_SYMBOL_STUBS and associated additional indirect symbol entries), as that's only used on i386 (where the stubs are self-modifying). So, this now works: extern int _printf(const char*, ...); int _start(void) { _printf("hello\n"); return 0; }
2020-05-18 10:35:38 +08:00
/* Stub creation belongs to check_relocs, but we need to create
the symbol now, so its included in the sorting. */
mo->stubs = new_section(s1, "__stubs", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR);
mo->stubsym = put_elf_sym(s1->symtab, 0, 0,
ELFW(ST_INFO)(STB_LOCAL, STT_NOTYPE), 0,
mo->stubs->sh_num, ".__stubs");
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
mo->symtab = new_section(s1, "LESYMTAB", SHT_LINKEDIT, SHF_ALLOC | SHF_WRITE);
mo->strtab = new_section(s1, "LESTRTAB", SHT_LINKEDIT, SHF_ALLOC | SHF_WRITE);
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
put_elf_str(mo->strtab, " "); /* Mach-O starts strtab with a space */
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
sym_end = symtab_section->data_offset / sizeof(ElfW(Sym));
pn = section_ptr_add(mo->symtab, sizeof(*pn) * (sym_end - 1));
for (sym_index = 1; sym_index < sym_end; ++sym_index) {
ElfW(Sym) *sym = (ElfW(Sym) *)symtab_section->data + sym_index;
const char *name = (char*)symtab_section->link->data + sym->st_name;
pn[sym_index - 1].n_strx = put_elf_str(mo->strtab, name);
pn[sym_index - 1].n_value = sym_index;
}
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
tcc_enter_state(s1); /* qsort needs global state */
qsort(pn, sym_end - 1, sizeof(*pn), machosymcmp);
tcc_exit_state();
mo->e2msym = tcc_malloc(sym_end * sizeof(*mo->e2msym));
mo->e2msym[0] = -1;
for (sym_index = 1; sym_index < sym_end; ++sym_index) {
mo->e2msym[pn[sym_index - 1].n_value] = sym_index - 1;
}
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
}
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
struct {
int seg;
uint32_t flags;
char *name;
} skinfo[sk_last] = {
[sk_text] = { 1, 0x80000400, "__text" },
[sk_ro_data] = { 1, 0, "__rodata" },
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
[sk_nl_ptr] = { 2, 6, "__got" }, /* S_NON_LAZY_SYMBOL_POINTERS */
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
[sk_rw_data] = { 2, 0, "__data" },
[sk_bss] = { 2, 1, "__bss" },
[sk_linkedit] = { 3, 0, NULL },
};
static void collect_sections(TCCState *s1, struct macho *mo)
{
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
int i, sk, numsec;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
uint64_t curaddr, fileofs;
Section *s;
struct segment_command_64 *seg = NULL;
struct dylinker_command *dyldlc;
struct symtab_command *symlc;
struct dysymtab_command *dysymlc;
char *str;
//struct segment_command_64 *zc, *tc, *sc, *lc;
add_segment(mo, "__PAGEZERO");
add_segment(mo, "__TEXT");
add_segment(mo, "__DATA");
add_segment(mo, "__LINKEDIT");
mo->seg[0]->vmsize = (uint64_t)1 << 32;
mo->seg[1]->vmaddr = (uint64_t)1 << 32;
mo->seg[1]->maxprot = 7; // rwx
mo->seg[1]->initprot = 5; // r-x
mo->seg[2]->vmaddr = -1;
mo->seg[2]->maxprot = 7; // rwx
mo->seg[2]->initprot = 3; // rw-
mo->seg[3]->vmaddr = -1;
mo->seg[3]->maxprot = 7; // rwx
mo->seg[3]->initprot = 1; // r--
mo->ep.cmd = LC_MAIN;
mo->ep.cmdsize = sizeof(mo->ep);
mo->ep.entryoff = 4096; // XXX
mo->ep.stacksize = 0;
add_lc(mo, &mo->ep);
i = (sizeof(*dyldlc) + strlen("/usr/lib/dyld") + 1 + 7) &-8;
dyldlc = tcc_mallocz(i);
dyldlc->cmd = LC_LOAD_DYLINKER;
dyldlc->cmdsize = i;
dyldlc->name = sizeof(*dyldlc);
str = (char*)dyldlc + dyldlc->name;
strcpy(str, "/usr/lib/dyld");
add_lc(mo, dyldlc);
symlc = tcc_mallocz(sizeof(*symlc));
symlc->cmd = LC_SYMTAB;
symlc->cmdsize = sizeof(*symlc);
add_lc(mo, symlc);
dysymlc = tcc_mallocz(sizeof(*dysymlc));
dysymlc->cmd = LC_DYSYMTAB;
dysymlc->cmdsize = sizeof(*dysymlc);
add_lc(mo, dysymlc);
add_dylib(mo, "/usr/lib/libSystem.B.dylib");
mo->linkedit = new_section(s1, "LINKEDIT", SHT_LINKEDIT, SHF_ALLOC | SHF_WRITE);
/* LINKEDIT can't be empty (XXX remove once we have symbol table) */
section_ptr_add(mo->linkedit, 256);
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
/* dyld requires a writable segment, but ignores zero-sized segments
for this, so force to have some data. */
mo->wdata = new_section(s1, " wdata", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
section_ptr_add(mo->wdata, 64);
memset (mo->sk_to_sect, 0, sizeof(mo->sk_to_sect));
for (i = s1->nb_sections; i-- > 1;) {
int type, flags;
s = s1->sections[i];
type = s->sh_type;
flags = s->sh_flags;
sk = sk_unknown;
if (flags & SHF_ALLOC) {
switch (type) {
default: sk = sk_unknown; break;
case SHT_NOBITS: sk = sk_bss; break;
case SHT_SYMTAB: sk = sk_discard; break;
case SHT_STRTAB: sk = sk_discard; break;
case SHT_RELX: sk = sk_discard; break;
case SHT_LINKEDIT: sk = sk_linkedit; break;
case SHT_PROGBITS:
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
if (s == s1->got)
sk = sk_nl_ptr;
else if (flags & SHF_EXECINSTR)
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
sk = sk_text;
else if (flags & SHF_WRITE)
sk = sk_rw_data;
else
sk = sk_ro_data;
break;
}
} else
sk = sk_discard;
s->prev = mo->sk_to_sect[sk].s;
mo->sk_to_sect[sk].s = s;
}
fileofs = 4096; /* leave space for mach-o headers */
curaddr = mo->seg[1]->vmaddr;
curaddr += 4096;
seg = NULL;
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
numsec = 0;
mo->elfsectomacho = tcc_mallocz(sizeof(*mo->elfsectomacho) * s1->nb_sections);
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
for (sk = sk_unknown; sk < sk_last; sk++) {
struct section_64 *sec = NULL;
if (seg) {
seg->vmsize = curaddr - seg->vmaddr;
seg->filesize = fileofs - seg->fileoff;
}
if (skinfo[sk].seg && mo->sk_to_sect[sk].s) {
uint64_t al = 0;
int si;
seg = mo->seg[skinfo[sk].seg];
if (skinfo[sk].name) {
si = add_section(mo, &seg, skinfo[sk].name);
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
numsec++;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
mo->seg[skinfo[sk].seg] = seg;
mo->sk_to_sect[sk].machosect = si;
sec = get_section(seg, si);
sec->flags = skinfo[sk].flags;
}
if (seg->vmaddr == -1) {
curaddr = (curaddr + 4095) & -4096;
seg->vmaddr = curaddr;
fileofs = (fileofs + 4095) & -4096;
seg->fileoff = fileofs;
}
for (s = mo->sk_to_sect[sk].s; s; s = s->prev) {
int a = exact_log2p1(s->sh_addralign);
if (a && al < (a - 1))
al = a - 1;
s->sh_size = s->data_offset;
}
if (sec)
sec->align = al;
al = 1U << al;
if (al > 4096)
tcc_warning("alignment > 4096"), sec->align = 12, al = 4096;
curaddr = (curaddr + al - 1) & -al;
fileofs = (fileofs + al - 1) & -al;
if (sec) {
sec->addr = curaddr;
sec->offset = fileofs;
}
for (s = mo->sk_to_sect[sk].s; s; s = s->prev) {
al = s->sh_addralign;
curaddr = (curaddr + al - 1) & -al;
tcc_warning("curaddr now 0x%llx", curaddr);
s->sh_addr = curaddr;
curaddr += s->sh_size;
if (s->sh_type != SHT_NOBITS) {
fileofs = (fileofs + al - 1) & -al;
s->sh_offset = fileofs;
fileofs += s->sh_size;
tcc_warning("fileofs now %lld", fileofs);
}
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
if (sec)
mo->elfsectomacho[s->sh_num] = numsec;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
}
if (sec)
sec->size = curaddr - sec->addr;
}
for (s = mo->sk_to_sect[sk].s; s; s = s->prev) {
int type = s->sh_type;
int flags = s->sh_flags;
printf("%d section %-16s %-10s %09llx %04x %02d %s,%s,%s\n",
sk,
s->name,
type == SHT_PROGBITS ? "progbits" :
type == SHT_NOBITS ? "nobits" :
type == SHT_SYMTAB ? "symtab" :
type == SHT_STRTAB ? "strtab" :
type == SHT_RELX ? "rel" : "???",
s->sh_addr,
(unsigned)s->data_offset,
s->sh_addralign,
flags & SHF_ALLOC ? "alloc" : "",
flags & SHF_WRITE ? "write" : "",
flags & SHF_EXECINSTR ? "exec" : ""
);
}
}
if (seg) {
seg->vmsize = curaddr - seg->vmaddr;
seg->filesize = fileofs - seg->fileoff;
}
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
/* Fill symtab info */
symlc->symoff = mo->symtab->sh_offset;
symlc->nsyms = mo->symtab->data_offset / sizeof(struct nlist_64);
symlc->stroff = mo->strtab->sh_offset;
symlc->strsize = mo->strtab->data_offset;
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
dysymlc->iundefsym = mo->iundef == -1 ? symlc->nsyms : mo->iundef;
dysymlc->iextdefsym = mo->iextdef == -1 ? dysymlc->iundefsym : mo->iextdef;
dysymlc->ilocalsym = mo->ilocal == -1 ? dysymlc->iextdefsym : mo->ilocal;
dysymlc->nlocalsym = dysymlc->iextdefsym - dysymlc->ilocalsym;
dysymlc->nextdefsym = dysymlc->iundefsym - dysymlc->iextdefsym;
dysymlc->nundefsym = symlc->nsyms - dysymlc->iundefsym;
dysymlc->indirectsymoff = mo->indirsyms->sh_offset;
dysymlc->nindirectsyms = mo->indirsyms->data_offset / sizeof(uint32_t);
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
}
static void macho_write(TCCState *s1, struct macho *mo, FILE *fp)
{
int i, sk;
uint64_t fileofs = 0;
Section *s;
mo->mh.mh.magic = MH_MAGIC_64;
mo->mh.mh.cputype = 0x1000007; // x86_64
mo->mh.mh.cpusubtype = 0x80000003;// all | CPU_SUBTYPE_LIB64
mo->mh.mh.filetype = 2; // MH_EXECUTE
mo->mh.mh.flags = 4; // DYLDLINK
mo->mh.mh.ncmds = mo->nseg + mo->nlc;
mo->mh.mh.sizeofcmds = 0;
for (i = 0; i < mo->nseg; i++)
mo->mh.mh.sizeofcmds += mo->seg[i]->cmdsize;
for (i = 0; i < mo->nlc; i++)
mo->mh.mh.sizeofcmds += mo->lc[i]->cmdsize;
fwrite(&mo->mh, 1, sizeof(mo->mh), fp);
fileofs += sizeof(mo->mh);
for (i = 0; i < mo->nseg; i++) {
fwrite(mo->seg[i], 1, mo->seg[i]->cmdsize, fp);
fileofs += mo->seg[i]->cmdsize;
}
for (i = 0; i < mo->nlc; i++) {
fwrite(mo->lc[i], 1, mo->lc[i]->cmdsize, fp);
fileofs += mo->lc[i]->cmdsize;
}
for (sk = sk_unknown; sk < sk_last; sk++) {
struct segment_command_64 *seg;
//struct section_64 *sec;
if (!skinfo[sk].seg || !mo->sk_to_sect[sk].s)
continue;
seg = mo->seg[skinfo[sk].seg];
/*sec = get_section(seg, mo->sk_to_sect[sk].machosect);
while (fileofs < sec->offset)
fputc(0, fp), fileofs++;*/
for (s = mo->sk_to_sect[sk].s; s; s = s->prev) {
if (s->sh_type != SHT_NOBITS) {
while (fileofs < s->sh_offset)
fputc(0, fp), fileofs++;
if (s->sh_size) {
fwrite(s->data, 1, s->sh_size, fp);
fileofs += s->sh_size;
}
}
}
}
}
ST_FUNC int macho_output_file(TCCState *s1, const char *filename)
{
int fd, mode, file_type;
FILE *fp;
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
int ret = -1;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
struct macho mo = {0,};
file_type = s1->output_type;
if (file_type == TCC_OUTPUT_OBJ)
mode = 0666;
else
mode = 0777;
unlink(filename);
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, mode);
if (fd < 0) {
tcc_error_noabort("could not write '%s: %s'", filename, strerror(errno));
return -1;
}
fp = fdopen(fd, "wb");
if (s1->verbose)
printf("<- %s\n", filename);
resolve_common_syms(s1);
macos: dynamic symbol table and __got this now sorts the symbols properly (local, global defined, undefined; the latter two by name), marks the three ranges within LC_DYSYMTAB, generates a __got section (non-lazy pointers) and slots for relocations which need them, and the indirect symbol mapping for them. This doesn't yet deal with undefined symbols. But it means compared to last example now this also works, i.e. read access to _global_ data: % cat simple3.c int loc = 42; int _start(void) { return loc - 42; }
2020-05-17 10:19:59 +08:00
create_symtab(s1, &mo);
check_relocs(s1, &mo);
ret = check_symbols(s1, &mo);
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
if (!ret) {
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
int i;
Section *s;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
collect_sections(s1, &mo);
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
relocate_syms(s1, s1->symtab, 0);
if (s1->nb_errors)
goto do_ret;
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (s->reloc)
relocate_section(s1, s);
}
convert_symbols(s1, &mo);
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
macho_write(s1, &mo, fp);
}
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
ret = 0;
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
macos: Create symtab this creates a proper LC_SYMTAB, with reasonable entries. It's not sorted, so not usable for LC_DYSYMTAB. But 'nm -x -no-sort' allows to see us some useful info. This also relocates sections and symbols, so now this example works as well (i.e. read access to static local data): % cat simple2.c static int loc = 42; int main(void) { return loc - 42; }
2020-05-16 09:26:53 +08:00
do_ret:
macos: First cut at generating Mach-O executables this does generate a working executable for a very simple example input, e.g. this: % cat simple.c int main(void) { return 0; } % ./tcc -B. -c simple.c % ./tcc -nostdlib -B. simple.o -lc % ./a.out && echo okay okay (the -lc is actually not necessary right now, see below). This has many limitations: * no symbol table, hence no calls to external functions from e.g. libc, aka libSystemB * no proper entry point (should be main, but is hardcoded to first real .text address) * libSystemB is hardcoded, no other libs are supported (but again no external calls anyway) * generated Mach-O executable is in old format: neither LC_DYLD_INFO no export tries for symbols are created (no symbol table at all!) * the __LINKEDIT segment is faked and empty, as dyld doesn't like it empty even if no symbols point into it * same with __DATA, dyld wants a non-empty writable segment which we enforce with useless data * no relocations, hence no function call stubs (lazy or not) are generated * hardcodes some other constants as well
2020-05-15 09:46:55 +08:00
fclose(fp);
return ret;
}
Reference in New Issue Copy Permalink