OSX/iOS: Always generate 64 bit non-FAT Mach-O object files.

Reported by Sergey Bronnikov. #1181

src/jit/bcsave.lua

@@ -439,24 +439,12 @@ typedef struct
 {
   mach_header; uint32_t reserved;
 } mach_header_64;
-typedef struct {
-  uint32_t cmd, cmdsize;
-  char segname[16];
-  uint32_t vmaddr, vmsize, fileoff, filesize;
-  uint32_t maxprot, initprot, nsects, flags;
-} mach_segment_command;
 typedef struct {
   uint32_t cmd, cmdsize;
   char segname[16];
   uint64_t vmaddr, vmsize, fileoff, filesize;
   uint32_t maxprot, initprot, nsects, flags;
 } mach_segment_command_64;
-typedef struct {
-  char sectname[16], segname[16];
-  uint32_t addr, size;
-  uint32_t offset, align, reloff, nreloc, flags;
-  uint32_t reserved1, reserved2;
-} mach_section;
 typedef struct {
   char sectname[16], segname[16];
   uint64_t addr, size;
@@ -466,133 +454,58 @@ typedef struct {
 typedef struct {
   uint32_t cmd, cmdsize, symoff, nsyms, stroff, strsize;
 } mach_symtab_command;
-typedef struct {
-  int32_t strx;
-  uint8_t type, sect;
-  int16_t desc;
-  uint32_t value;
-} mach_nlist;
 typedef struct {
   int32_t strx;
   uint8_t type, sect;
   uint16_t desc;
   uint64_t value;
 } mach_nlist_64;
-typedef struct
-{
-  int32_t magic, nfat_arch;
-} mach_fat_header;
-typedef struct
-{
-  int32_t cputype, cpusubtype, offset, size, align;
-} mach_fat_arch;
 typedef struct {
-  struct {
-    mach_header hdr;
-    mach_segment_command seg;
-    mach_section sec;
-    mach_symtab_command sym;
-  } arch[1];
-  mach_nlist sym_entry;
-  uint8_t space[4096];
-} mach_obj;
-typedef struct {
-  struct {
   mach_header_64 hdr;
   mach_segment_command_64 seg;
   mach_section_64 sec;
   mach_symtab_command sym;
-  } arch[1];
   mach_nlist_64 sym_entry;
   uint8_t space[4096];
 } mach_obj_64;
-typedef struct {
-  mach_fat_header fat;
-  mach_fat_arch fat_arch[2];
-  struct {
-    mach_header hdr;
-    mach_segment_command seg;
-    mach_section sec;
-    mach_symtab_command sym;
-  } arch[2];
-  mach_nlist sym_entry;
-  uint8_t space[4096];
-} mach_fat_obj;
-typedef struct {
-  mach_fat_header fat;
-  mach_fat_arch fat_arch[2];
-  struct {
-    mach_header_64 hdr;
-    mach_segment_command_64 seg;
-    mach_section_64 sec;
-    mach_symtab_command sym;
-  } arch[2];
-  mach_nlist_64 sym_entry;
-  uint8_t space[4096];
-} mach_fat_obj_64;
 ]]
   local symname = '_'..LJBC_PREFIX..ctx.modname
-  local isfat, is64, align, mobj = false, false, 4, "mach_obj"
+  local cputype, cpusubtype = 0x01000007, 3
-  if ctx.arch == "x64" then
+  if ctx.arch ~= "x64" then
-    is64, align, mobj = true, 8, "mach_obj_64"
+    check(ctx.arch == "arm64", "unsupported architecture for OSX")
-  elseif ctx.arch == "arm" then
+    cputype, cpusubtype = 0x0100000c, 0
-    isfat, mobj = true, "mach_fat_obj"
-  elseif ctx.arch == "arm64" then
-    is64, align, isfat, mobj = true, 8, true, "mach_fat_obj_64"
-  else
-    check(ctx.arch == "x86", "unsupported architecture for OSX")
   end
   local function aligned(v, a) return bit.band(v+a-1, -a) end
-  local be32 = bit.bswap -- Mach-O FAT is BE, supported archs are LE.
 
   -- Create Mach-O object and fill in header.
-  local o = ffi.new(mobj)
+  local o = ffi.new("mach_obj_64")
-  local mach_size = aligned(ffi.offsetof(o, "space")+#symname+2, align)
+  local mach_size = aligned(ffi.offsetof(o, "space")+#symname+2, 8)
-  local cputype = ({ x86={7}, x64={0x01000007}, arm={7,12}, arm64={0x01000007,0x0100000c} })[ctx.arch]
-  local cpusubtype = ({ x86={3}, x64={3}, arm={3,9}, arm64={3,0} })[ctx.arch]
-  if isfat then
-    o.fat.magic = be32(0xcafebabe)
-    o.fat.nfat_arch = be32(#cpusubtype)
-  end
 
   -- Fill in sections and symbols.
-  for i=0,#cpusubtype-1 do
+  o.hdr.magic = 0xfeedfacf
-    local ofs = 0
+  o.hdr.cputype = cputype
-    if isfat then
+  o.hdr.cpusubtype = cpusubtype
-      local a = o.fat_arch[i]
+  o.hdr.filetype = 1
-      a.cputype = be32(cputype[i+1])
+  o.hdr.ncmds = 2
-      a.cpusubtype = be32(cpusubtype[i+1])
+  o.hdr.sizeofcmds = ffi.sizeof(o.seg)+ffi.sizeof(o.sec)+ffi.sizeof(o.sym)
-      -- Subsequent slices overlap each other to share data.
+  o.seg.cmd = 0x19
-      ofs = ffi.offsetof(o, "arch") + i*ffi.sizeof(o.arch[0])
+  o.seg.cmdsize = ffi.sizeof(o.seg)+ffi.sizeof(o.sec)
-      a.offset = be32(ofs)
+  o.seg.vmsize = #s
-      a.size = be32(mach_size-ofs+#s)
+  o.seg.fileoff = mach_size
-    end
+  o.seg.filesize = #s
-    local a = o.arch[i]
+  o.seg.maxprot = 1
-    a.hdr.magic = is64 and 0xfeedfacf or 0xfeedface
+  o.seg.initprot = 1
-    a.hdr.cputype = cputype[i+1]
+  o.seg.nsects = 1
-    a.hdr.cpusubtype = cpusubtype[i+1]
+  ffi.copy(o.sec.sectname, "__data")
-    a.hdr.filetype = 1
+  ffi.copy(o.sec.segname, "__DATA")
-    a.hdr.ncmds = 2
+  o.sec.size = #s
-    a.hdr.sizeofcmds = ffi.sizeof(a.seg)+ffi.sizeof(a.sec)+ffi.sizeof(a.sym)
+  o.sec.offset = mach_size
-    a.seg.cmd = is64 and 0x19 or 0x1
+  o.sym.cmd = 2
-    a.seg.cmdsize = ffi.sizeof(a.seg)+ffi.sizeof(a.sec)
+  o.sym.cmdsize = ffi.sizeof(o.sym)
-    a.seg.vmsize = #s
+  o.sym.symoff = ffi.offsetof(o, "sym_entry")
-    a.seg.fileoff = mach_size-ofs
+  o.sym.nsyms = 1
-    a.seg.filesize = #s
+  o.sym.stroff = ffi.offsetof(o, "sym_entry")+ffi.sizeof(o.sym_entry)
-    a.seg.maxprot = 1
+  o.sym.strsize = aligned(#symname+2, 8)
-    a.seg.initprot = 1
-    a.seg.nsects = 1
-    ffi.copy(a.sec.sectname, "__data")
-    ffi.copy(a.sec.segname, "__DATA")
-    a.sec.size = #s
-    a.sec.offset = mach_size-ofs
-    a.sym.cmd = 2
-    a.sym.cmdsize = ffi.sizeof(a.sym)
-    a.sym.symoff = ffi.offsetof(o, "sym_entry")-ofs
-    a.sym.nsyms = 1
-    a.sym.stroff = ffi.offsetof(o, "sym_entry")+ffi.sizeof(o.sym_entry)-ofs
-    a.sym.strsize = aligned(#symname+2, align)
-  end
   o.sym_entry.type = 0xf
   o.sym_entry.sect = 1
   o.sym_entry.strx = 1