plan9 cleanups

 * rename files to adhere to conventions
 * remove unnecessary function / optionality
 * fix merge conflict
 * better panic message
 * remove unnecessary TODO comment
 * proper namespacing of declarations
 * clean up documentation comments
 * no copyright header needed for a brand new zig file that is not
   copied from anywhere

1 files changed, 114 insertions, 0 deletions

diff --git a/src/link/Plan9/aout.zig b/src/link/Plan9/aout.zig
new file mode 100644
index 0000000000..f6dff7437c
--- /dev/null
+++ b/src/link/Plan9/aout.zig
@@ -0,0 +1,114 @@
+const std = @import("std");
+const assert = std.debug.assert;
+
+/// All integers are in big-endian format (needs a byteswap).
+pub const ExecHdr = extern struct {
+    magic: u32,
+    text: u32,
+    data: u32,
+    bss: u32,
+    syms: u32,
+    /// You should truncate this to 32 bits on 64 bit systems, then but the actual 8 bytes
+    /// in the fat header.
+    entry: u32,
+    spsz: u32,
+    pcsz: u32,
+    comptime {
+        assert(@sizeOf(@This()) == 32);
+    }
+    /// It is up to the caller to disgard the last 8 bytes if the header is not fat.
+    pub fn toU8s(self: *@This()) [40]u8 {
+        var buf: [40]u8 = undefined;
+        var i: u8 = 0;
+        inline for (std.meta.fields(@This())) |f| {
+            std.mem.writeIntSliceBig(u32, buf[i .. i + 4], @field(self, f.name));
+            i += 4;
+        }
+        return buf;
+    }
+};
+
+pub const Sym = struct {
+    /// Big endian in the file
+    value: u64,
+    type: Type,
+    name: []const u8,
+
+    /// The type field is one of the following characters with the
+    /// high bit set:
+    /// T    text segment symbol
+    /// t    static text segment symbol
+    /// L    leaf function text segment symbol
+    /// l    static leaf function text segment symbol
+    /// D    data segment symbol
+    /// d    static data segment symbol
+    /// B    bss segment symbol
+    /// b    static bss segment symbol
+    /// a    automatic (local) variable symbol
+    /// p    function parameter symbol
+    /// f    source file name components
+    /// z    source file name
+    /// Z    source file line offset
+    /// m for '.frame'
+    pub const Type = enum(u8) {
+        T = 0x80 | 'T',
+        t = 0x80 | 't',
+        L = 0x80 | 'L',
+        l = 0x80 | 'l',
+        D = 0x80 | 'D',
+        d = 0x80 | 'd',
+        B = 0x80 | 'B',
+        b = 0x80 | 'b',
+        a = 0x80 | 'a',
+        p = 0x80 | 'p',
+        f = 0x80 | 'f',
+        z = 0x80 | 'z',
+        Z = 0x80 | 'Z',
+        m = 0x80 | 'm',
+
+        pub fn toGlobal(self: Type) Type {
+            return switch (self) {
+                .t => .T,
+                .b => .B,
+                .d => .D,
+                else => unreachable,
+            };
+        }
+    };
+};
+
+pub const HDR_MAGIC = 0x00008000;
+pub inline fn _MAGIC(f: anytype, b: anytype) @TypeOf(f | ((((@as(c_int, 4) * b) + @as(c_int, 0)) * b) + @as(c_int, 7))) {
+    return f | ((((@as(c_int, 4) * b) + @as(c_int, 0)) * b) + @as(c_int, 7));
+}
+pub const A_MAGIC = _MAGIC(0, 8); // 68020
+pub const I_MAGIC = _MAGIC(0, 11); // intel 386
+pub const J_MAGIC = _MAGIC(0, 12); // intel 960 (retired)
+pub const K_MAGIC = _MAGIC(0, 13); // sparc
+pub const V_MAGIC = _MAGIC(0, 16); // mips 3000 BE
+pub const X_MAGIC = _MAGIC(0, 17); // att dsp 3210 (retired)
+pub const M_MAGIC = _MAGIC(0, 18); // mips 4000 BE
+pub const D_MAGIC = _MAGIC(0, 19); // amd 29000 (retired)
+pub const E_MAGIC = _MAGIC(0, 20); // arm
+pub const Q_MAGIC = _MAGIC(0, 21); // powerpc
+pub const N_MAGIC = _MAGIC(0, 22); // mips 4000 LE
+pub const L_MAGIC = _MAGIC(0, 23); // dec alpha (retired)
+pub const P_MAGIC = _MAGIC(0, 24); // mips 3000 LE
+pub const U_MAGIC = _MAGIC(0, 25); // sparc64
+pub const S_MAGIC = _MAGIC(HDR_MAGIC, 26); // amd64
+pub const T_MAGIC = _MAGIC(HDR_MAGIC, 27); // powerpc64
+pub const R_MAGIC = _MAGIC(HDR_MAGIC, 28); // arm64
+
+pub fn magicFromArch(arch: std.Target.Cpu.Arch) !u32 {
+    return switch (arch) {
+        .i386 => I_MAGIC,
+        .sparc => K_MAGIC, // TODO should sparcv9 and sparcel go here?
+        .mips => V_MAGIC,
+        .arm => E_MAGIC,
+        .aarch64 => R_MAGIC,
+        .powerpc => Q_MAGIC,
+        .powerpc64 => T_MAGIC,
+        .x86_64 => S_MAGIC,
+        else => error.ArchNotSupportedByPlan9,
+    };
+}