Add fat/universal dylib support to zig ld

With this change zig ld can link with dynamic libraries
contained within a fat/universal file that had multiple
seperate binaries embedded within it for multi-arch
support (in macOS).

Whilst zig can still only create single-architecture
executables - the ability to link with fat libraries is
useful for cases where they are the easiest (or only)
option to link against.

1 files changed, 4 insertions, 24 deletions

diff --git a/lib/std/elf.zig b/lib/std/elf.zig
index b74ea6e837..6c90dff929 100644
--- a/lib/std/elf.zig
+++ b/lib/std/elf.zig
@@ -429,7 +429,7 @@ pub fn ProgramHeaderIterator(ParseSource: anytype) type {
                 if (self.elf_header.endian == native_endian) return phdr;
 
                 // Convert fields to native endianness.
-                bswapAllFields(Elf64_Phdr, &phdr);
+                mem.bswapAllFields(Elf64_Phdr, &phdr);
                 return phdr;
             }
 
@@ -441,7 +441,7 @@ pub fn ProgramHeaderIterator(ParseSource: anytype) type {
             // ELF endianness does NOT match native endianness.
             if (self.elf_header.endian != native_endian) {
                 // Convert fields to native endianness.
-                bswapAllFields(Elf32_Phdr, &phdr);
+                mem.bswapAllFields(Elf32_Phdr, &phdr);
             }
 
             // Convert 32-bit header to 64-bit.
@@ -479,7 +479,7 @@ pub fn SectionHeaderIterator(ParseSource: anytype) type {
                 if (self.elf_header.endian == native_endian) return shdr;
 
                 // Convert fields to native endianness.
-                bswapAllFields(Elf64_Shdr, &shdr);
+                mem.bswapAllFields(Elf64_Shdr, &shdr);
                 return shdr;
             }
 
@@ -491,7 +491,7 @@ pub fn SectionHeaderIterator(ParseSource: anytype) type {
             // ELF endianness does NOT match native endianness.
             if (self.elf_header.endian != native_endian) {
                 // Convert fields to native endianness.
-                bswapAllFields(Elf32_Shdr, &shdr);
+                mem.bswapAllFields(Elf32_Shdr, &shdr);
             }
 
             // Convert 32-bit header to 64-bit.
@@ -531,26 +531,6 @@ pub fn int32(need_bswap: bool, int_32: anytype, comptime Int64: anytype) Int64 {
     }
 }
 
-pub fn bswapAllFields(comptime S: type, ptr: *S) void {
-    if (@typeInfo(S) != .Struct) @compileError("bswapAllFields expects a struct as the first argument");
-    inline for (std.meta.fields(S)) |f| {
-        @field(ptr, f.name) = @byteSwap(f.field_type, @field(ptr, f.name));
-    }
-}
-test "bswapAllFields" {
-    var s: Elf32_Chdr = .{
-        .ch_type = 0x12341234,
-        .ch_size = 0x56785678,
-        .ch_addralign = 0x12124242,
-    };
-    bswapAllFields(Elf32_Chdr, &s);
-    try std.testing.expectEqual(Elf32_Chdr{
-        .ch_type = 0x34123412,
-        .ch_size = 0x78567856,
-        .ch_addralign = 0x42421212,
-    }, s);
-}
-
 pub const EI_NIDENT = 16;
 
 pub const EI_CLASS = 4;