Hojun-Cho
e217cd32d1
Ports cmd/6l/{dyn,dynout}.c into selfhost/cmd/6l/{dyn,dynout}.ww:
ET_DYN .so loading + PT_INTERP/PT_DYNAMIC ELF emission with .rela.plt,
.gnu.version_r, BIND_NOW. lsym grows dyn fields; pass.ww promotes
undefs to dyn; out.ww dispatches; main.ww takes -L/-l. The ww driver
forwards -L/-l to 6l_ww so 'ww_ww build snake.ww -L /usr/lib -l ncurses
-l c' runs without cc.
Test 996 pins byte-identical output to C-6l on snake.
'make bootstrap' gains a fourth stage with cmp ww3 == ww4, proving
ww3 is byte-stable when used as a compiler — not just a coincidental
two-stage equilibrium.
Four wwstage 6c cgen quirks surfaced and are documented in dynout.ww's
header (two-level field-write through a pointer field, (scalar, str)
tuple returns, def : str, ≤6 arg calling convention).
101 lines
3.1 KiB
Plaintext
101 lines
3.1 KiB
Plaintext
// selfhost/cmd/6l/out.ww — port of cmd/6l/out.c.
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//
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// Emit a static ELF64 executable. File layout (per the C original):
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// [0..64) Ehdr
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// [64..120) Phdr (one PT_LOAD)
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// [120..0x1000) zero pad
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// [0x1000..) .text bytes
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// Single PT_LOAD covers the whole file, R+X. No interpreter, no .bss.
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use os;
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use sym;
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use dynout;
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def ET_EXEC: u16 = 2u16;
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def EM_X86_64_W: u16 = 62u16;
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def EV_CURRENT: u32 = 1u32;
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def ELFCLASS64: u8 = 2u8;
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def ELFDATA2LSB: u8 = 1u8;
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def PT_LOAD: u32 = 1u32;
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def PF_X: u32 = 1u32;
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def PF_R: u32 = 4u32;
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def TEXT_OFF: u64 = 4096u64; // 0x1000
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// ---- little-endian byte writers ----------------------------------------
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fn wr_u16(buf: *u8, off: u64, v: u16) void = {
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buf[off] = (v & 255u16): u8;
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buf[off + 1u64] = ((v >> 8u16) & 255u16): u8;
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};
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fn wr_u32(buf: *u8, off: u64, v: u32) void = {
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buf[off] = (v & 255u32): u8;
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buf[off + 1u64] = ((v >> 8u32) & 255u32): u8;
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buf[off + 2u64] = ((v >> 16u32) & 255u32): u8;
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buf[off + 3u64] = ((v >> 24u32) & 255u32): u8;
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};
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fn wr_u64(buf: *u8, off: u64, v: u64) void = {
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wr_u32(buf, off, (v & 4294967295u64): u32);
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wr_u32(buf, off + 4u64, ((v >> 32u64) & 4294967295u64): u32);
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};
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// ---- emit ---------------------------------------------------------------
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export fn l_emit_elf(l: *lnk, fd: i32, base: u64, entry: u64) i32 = {
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// Dispatch: any loaded shared object plus any dynamic ref means
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// we owe the loader a real PT_INTERP/PT_DYNAMIC binary.
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if (l.sos != nil) {
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if (l.dyn_n > 0) {
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return l_emit_dyn_elf(l, fd, base, entry);
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};
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};
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let filesz: u64 = TEXT_OFF + l.textlen;
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// One contiguous header buffer covering [0..0x1000), then .text.
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let hdr: *u8 = os.alloc(TEXT_OFF): *u8; // zero-initialised by mmap
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// --- Ehdr (64 bytes) ---
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hdr[0u64] = 127u8; // 0x7f
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hdr[1u64] = 69u8; // 'E'
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hdr[2u64] = 76u8; // 'L'
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hdr[3u64] = 70u8; // 'F'
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hdr[4u64] = ELFCLASS64;
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hdr[5u64] = ELFDATA2LSB;
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hdr[6u64] = EV_CURRENT: u8;
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wr_u16(hdr, 16u64, ET_EXEC); // e_type
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wr_u16(hdr, 18u64, EM_X86_64_W); // e_machine
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wr_u32(hdr, 20u64, EV_CURRENT); // e_version
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wr_u64(hdr, 24u64, entry); // e_entry
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wr_u64(hdr, 32u64, 64u64); // e_phoff = sizeof(Ehdr)
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wr_u64(hdr, 40u64, 0u64); // e_shoff
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wr_u32(hdr, 48u64, 0u32); // e_flags
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wr_u16(hdr, 52u64, 64u16); // e_ehsize
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wr_u16(hdr, 54u64, 56u16); // e_phentsize
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wr_u16(hdr, 56u64, 1u16); // e_phnum
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wr_u16(hdr, 58u64, 0u16); // e_shentsize
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wr_u16(hdr, 60u64, 0u16); // e_shnum
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wr_u16(hdr, 62u64, 0u16); // e_shstrndx
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// --- Phdr (56 bytes) at offset 64 ---
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wr_u32(hdr, 64u64, PT_LOAD); // p_type
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wr_u32(hdr, 68u64, PF_R | PF_X); // p_flags
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wr_u64(hdr, 72u64, 0u64); // p_offset
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wr_u64(hdr, 80u64, base); // p_vaddr
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wr_u64(hdr, 88u64, base); // p_paddr
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wr_u64(hdr, 96u64, filesz); // p_filesz
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wr_u64(hdr, 104u64, filesz); // p_memsz
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wr_u64(hdr, 112u64, TEXT_OFF); // p_align
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// Write [0..0x1000) then .text.
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let n1: i64 = os.writefull(fd, hdr, TEXT_OFF);
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if (n1 != TEXT_OFF: i64) { return -1; };
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if (l.textlen > 0u64) {
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let n2: i64 = os.writefull(fd, l.text, l.textlen);
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if (n2 != l.textlen: i64) { return -1; };
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};
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return 0;
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};
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