Files
ww/selfhost/cmd/w6l/obj.ww
Hojun-Cho 62c7771594 wcc/ww: self-hosted deterministic ar-writer + archive dup-detect (M3-tail c5a, #62)
Per-package .a archives are written by a self-hosted deterministic ar
writer (zeroed mtime/uid/gid, fixed mode 100644, stable member order)
so cstage and wwstage emit byte-identical archives. The linker
force-loads the root .o positionally and pulls deps from .a; a
post-pull PASS-3 over unloaded members reports duplicate symbols
through the archive (#31). Both stages mirrored (cmd/ + selfhost/).

USER-ruled D2 (self-hosted ar writer); pike P1/P2 link model. Gate
989_separchive_run proves cs.a==ww.a byte-identity, 3x-determinism,
link-consumes-.a (exit 7), and the masked-dup-through-.a loud fire.
2026-06-16 14:54:19 +09:00

646 lines
19 KiB
Plaintext

// selfhost/cmd/w6l/obj.ww — port of cmd/w6l/obj.c.
//
// Loads relocatable ELF64 .o files emitted by w6a, appends .text to
// the combined image, and pulls in symbols + relocations with
// offsets adjusted to the combined section.
//
// Also handles SysV `ar` archives (libwwrt.a). The two-pass loader
// indexes members on the first pass and iteratively pulls members
// that define currently-undefined symbols on subsequent passes.
package w6l;
import os;
import rt;
import strings;
import sym;
def ET_REL: i32 = 1;
def EM_X86_64: i32 = 62;
def SHT_PROGBITS: i32 = 1;
def SHT_SYMTAB: i32 = 2;
def SHT_STRTAB: i32 = 3;
def SHT_RELA: i32 = 4;
// ---- little-endian byte readers ----------------------------------------
// w6a/w6l use straight LE on amd64. Reading via byte offsets keeps us off
// the cgen's u16 field-load story for now (MOVZBQ exists; MOVZWQ doesn't).
fn rdu16(p: *u8, off: u64) u16 = {
let b0: u16 = p[off]: u16;
let b1: u16 = p[off + 1u64]: u16;
return b0 | (b1 << 8u16);
};
fn rdu32(p: *u8, off: u64) u32 = {
let b0: u32 = p[off]: u32;
let b1: u32 = p[off + 1u64]: u32;
let b2: u32 = p[off + 2u64]: u32;
let b3: u32 = p[off + 3u64]: u32;
return b0 | (b1 << 8u32) | (b2 << 16u32) | (b3 << 24u32);
};
fn rdu64(p: *u8, off: u64) u64 = {
let lo: u64 = rdu32(p, off): u64;
let hi: u64 = rdu32(p, off + 4u64): u64;
return lo | (hi << 32u64);
};
// ---- ELF64 section header offsets (40 bytes total) --------------------
def SHDR_SIZE: u64 = 64u64; // sizeof(Shdr) per ELF64 spec
def SHDR_NAME: u64 = 0u64;
def SHDR_TYPE: u64 = 4u64;
def SHDR_OFFSET: u64 = 24u64;
def SHDR_SIZE_F: u64 = 32u64;
def SHDR_LINK: u64 = 40u64;
// ELF64 ehdr field offsets
def EHDR_SIZE: u64 = 64u64;
def EHDR_TYPE: u64 = 16u64;
def EHDR_MACHINE: u64 = 18u64;
def EHDR_SHOFF: u64 = 40u64;
def EHDR_SHENTSIZE: u64 = 58u64;
def EHDR_SHNUM: u64 = 60u64;
def EHDR_SHSTRNDX: u64 = 62u64;
// ELF64 sym entry: 24 bytes
def SYM_SIZE: u64 = 24u64;
def SYM_NAME: u64 = 0u64;
def SYM_INFO: u64 = 4u64;
def SYM_SHNDX: u64 = 6u64;
def SYM_VALUE: u64 = 8u64;
// ELF64 RELA entry: 24 bytes
def RELA_SIZE: u64 = 24u64;
def RELA_OFFSET: u64 = 0u64;
def RELA_INFO: u64 = 8u64;
def RELA_ADDEND: u64 = 16u64;
// ---- file slurp --------------------------------------------------------
fn slurp(path: *u8) (*u8, u64) = {
let fd: i32 = os.open(pathstr(path), os.flag.RDONLY, 0i32);
if (fd < 0) { return nil, 0u64; };
let szr: (i64 | os.oserror) = os.filesize(fd);
let n: i64 = 0i64;
match (szr) {
case let v: i64 => n = v;
case let e: os.oserror => { os.close(fd); return nil, 0u64; };
};
let buf: []u8 = alloc([], n: u64)!;
buf.len = n: i32;
let rr: (i64 | os.oserror) = os.readall(fd, buf.ptr, n: u64);
os.close(fd);
let got: i64 = 0i64;
match (rr) {
case let v: i64 => got = v;
case let e: os.oserror => return nil, 0u64;
};
if (got != n) { return nil, 0u64; };
return buf.ptr, n: u64;
};
// ---- text buffer growth ------------------------------------------------
fn emittext(l: *lnk, src: *u8, n: u64) void = {
if (l.textlen + n > l.textcap) {
let nc: u64 = l.textcap;
if (nc == 0u64) { nc = 4096u64; };
for (nc < l.textlen + n) { nc = nc * 2u64; };
// Grow by mmap'ing a fresh region and copying. The old buffer
// is leaked into the page allocator; for a linker run this is
// trivial waste.
let nb: []u8 = alloc([], nc)!;
let i: u64 = 0u64;
for (i < l.textlen) {
nb[i] = l.text[i];
i += 1u64;
};
l.text = nb.ptr;
l.textcap = nc;
};
let i: u64 = 0u64;
for (i < n) {
l.text[l.textlen + i] = src[i];
i += 1u64;
};
l.textlen += n;
};
fn emitdata(l: *lnk, src: *u8, n: u64) void = {
if (l.datalen + n > l.datacap) {
let nc: u64 = l.datacap;
if (nc == 0u64) { nc = 256u64; };
for (nc < l.datalen + n) { nc = nc * 2u64; };
let nb: []u8 = alloc([], nc)!;
let i: u64 = 0u64;
for (i < l.datalen) {
nb[i] = l.data[i];
i += 1u64;
};
l.data = nb.ptr;
l.datacap = nc;
};
let i: u64 = 0u64;
for (i < n) {
l.data[l.datalen + i] = src[i];
i += 1u64;
};
l.datalen += n;
};
// ---- C-string helpers --------------------------------------------------
fn cstrlen(p: *u8) u64 = {
let n: u64 = 0u64;
for (p[n] != 0u8) { n += 1u64; };
return n;
};
// pathstr — view a NUL-terminated *u8 as a str. Bridges argv-style
// callers to lib/os entrypoints (str post-task-#23). Shared with
// main.ww and dyn.ww via the w6l bundle.
fn pathstr(p: *u8) str = {
let r: str;
r.ptr = p;
r.len = cstrlen(p): i32;
return r;
};
fn cstreq(p: *u8, lit: str) bool = {
let n: u64 = lit.len: u64;
let i: u64 = 0u64;
for (i < n) {
let li: i32 = i: i32;
if (p[i] != lit[li]) { return false; };
i += 1u64;
};
if (p[i] != 0u8) { return false; };
return true;
};
// Build a ww str from a NUL-terminated *u8 (for passing to intern).
fn cstrtostr(p: *u8) str = {
let n: u64 = cstrlen(p);
let view: str;
view.ptr = p;
view.len = n: i32;
return strings.dup(view);
};
// ---- archive (SysV ar) types and helpers -------------------------------
//
// Each archive member starts with a 60-byte ar_hdr. The fields we care
// about are the first byte (member type) and the size at offset 48 (a
// 10-byte, space-padded decimal). Member bodies are 2-byte aligned.
type defent = struct {
name: str,
dnext: *defent,
};
type armember = struct {
data: *u8, // owned heap copy of the member's ELF bytes
size: u64,
defs: *defent, // linked list of defined globals
loaded: i32,
mnext: *armember,
};
fn isarchive(p: *u8, len: u64) bool = {
if (len < 8u64) { return false; };
if (p[0u64] != '!' || p[1u64] != '<' || p[2u64] != 'a' || p[3u64] != 'r' ||
p[4u64] != 'c' || p[5u64] != 'h' || p[6u64] != '>' ||
p[7u64] != '\n') {
return false;
};
return true;
};
// arfield — parse a space-padded decimal integer of width n.
fn arfield(p: *u8, n: u64) u64 = {
let v: u64 = 0u64;
let i: u64 = 0u64;
for (i < n) {
let c: u8 = p[i];
if (c < 48u8) { return v; }; // space, NUL, etc.
if (c > 57u8) { return v; };
v = v * 10u64 + ((c - 48u8): u64);
i += 1u64;
};
return v;
};
// elfglobals — return a linked list of names of globally-defined
// (STB_GLOBAL) symbols whose section is `.text`. Names are owned
// heap copies, so the source ELF buffer can be freed afterward.
fn elfglobals(buf: *u8, len: u64) *defent = {
if (len < EHDR_SIZE) { return nil; };
if (buf[0u64] != 127u8) { return nil; };
if (buf[1u64] != 'E') { return nil; };
if (buf[2u64] != 'L') { return nil; };
if (buf[3u64] != 'F') { return nil; };
let shoff: u64 = rdu64(buf, EHDR_SHOFF);
let shnum: u32 = rdu16(buf, EHDR_SHNUM): u32;
let shstrndx: u32 = rdu16(buf, EHDR_SHSTRNDX): u32;
let shstrshoff: u64 = rdu64(buf, shoff + (shstrndx: u64) * SHDR_SIZE + SHDR_OFFSET);
let shstr: *u8 = buf + shstrshoff;
let idxtext: i32 = -1;
let idxdata: i32 = -1;
let idxsymtab: i32 = -1;
let i: u32 = 0u32;
for (i < shnum) {
let secoff: u64 = shoff + (i: u64) * SHDR_SIZE;
let shtype: u32 = rdu32(buf, secoff + SHDR_TYPE);
let shname: u32 = rdu32(buf, secoff + SHDR_NAME);
let nm: *u8 = shstr + (shname: u64);
if (shtype == SHT_PROGBITS: u32) {
if (cstreq(nm, ".text")) { idxtext = i: i32; };
if (cstreq(nm, ".data")) { idxdata = i: i32; };
};
if (shtype == SHT_SYMTAB: u32) { idxsymtab = i: i32; };
i += 1u32;
};
if (idxtext < 0) { return nil; };
if (idxsymtab < 0) { return nil; };
let symsh: u64 = shoff + (idxsymtab: u64) * SHDR_SIZE;
let symoff: u64 = rdu64(buf, symsh + SHDR_OFFSET);
let symsize: u64 = rdu64(buf, symsh + SHDR_SIZE_F);
let symlink: u32 = rdu32(buf, symsh + SHDR_LINK);
let nsyms: u64 = symsize / SYM_SIZE;
let strsh: u64 = shoff + (symlink: u64) * SHDR_SIZE;
let stroff: u64 = rdu64(buf, strsh + SHDR_OFFSET);
let strtab: *u8 = buf + stroff;
let head: *defent = nil;
let si: u64 = 1u64;
for (si < nsyms) {
let symp: u64 = symoff + si * SYM_SIZE;
let stname: u32 = rdu32(buf, symp + SYM_NAME);
let stinfo: u8 = buf[symp + SYM_INFO];
let stshndx: u16 = rdu16(buf, symp + SYM_SHNDX);
let bind: u32 = (stinfo: u32) >> 4u32;
// STB_GLOBAL = 1; defined in .text or .data. Both are
// included so an archive member that owns a data global
// gets pulled in when something references it.
if (bind == 1u32) {
if (stshndx != 0u16) {
let intext: bool = (stshndx: i32) == idxtext;
let indt: bool = false;
if (idxdata >= 0) {
indt = (stshndx: i32) == idxdata;
};
if (intext || indt) {
let nmp: *u8 = strtab + (stname: u64);
if (nmp[0u64] != 0u8) {
let nm: str = cstrtostr(nmp);
let de: *defent = alloc(defent { name = nm, dnext = head })!;
head = de;
};
};
};
};
si += 1u64;
};
return head;
};
// memberdefinesundef — true if any of m's defined globals matches a
// currently-undefined symbol in the linker's symbol table. Names not
// already interned are uninteresting (the link doesn't need them yet).
fn memberdefinesundef(l: *lnk, m: *armember) bool = {
let de: *defent = m.defs;
for (de != nil) {
let s: *lsym = lookup(l, de.name);
if (s != nil) {
if (s.defined == 0) { return true; };
};
de = de.dnext;
};
return false;
};
// loadarchive — port of cmd/w6l/obj.c:load_archive.
//
// Pass 1 indexes every regular member. Pass 2 iteratively pulls in any
// member that supplies a currently-undefined symbol; each pull may
// introduce fresh undefs, so we loop until quiescent.
fn loadarchive(l: *lnk, path: *u8, buf: *u8, len: u64) i32 = {
let head: *armember = nil;
let tail: *armember = nil;
let pos: u64 = 8u64; // past "!<arch>\n"
for (pos + 60u64 <= len) {
let hdrsize: u64 = arfield(buf + pos + 48u64, 10u64);
let hdrend: u64 = pos + 60u64;
if (hdrend + hdrsize > len) { break; };
let first: u8 = buf[pos];
// Skip the symbol table ('/'), long-name table ('//'), and
// any padding entries (NUL or space leading byte).
if (first != '/' && first != 0u8 && first != ' ') {
let m: *armember = alloc(armember { size = hdrsize })!;
let mbs: []u8 = alloc([], hdrsize)!;
let mb: *u8 = mbs.ptr;
let i: u64 = 0u64;
for (i < hdrsize) {
mb[i] = buf[hdrend + i];
i += 1u64;
};
m.data = mb;
m.defs = elfglobals(mb, hdrsize);
if (head == nil) { head = m; }
else { tail.mnext = m; };
tail = m;
};
pos = hdrend + hdrsize;
if ((hdrsize & 1u64) != 0u64) { pos = pos + 1u64; };
};
let changed: i32 = 1;
for (changed != 0) {
changed = 0;
let m: *armember = head;
for (m != nil) {
if (m.loaded == 0) {
if (memberdefinesundef(l, m)) {
if (loadimage(l, path, m.data, m.size) == 0) {
m.loaded = 1;
changed = 1;
};
};
};
m = m.mnext;
};
};
// Pass 3 (#31, task #62): catch a dup the selective pull MASKED. A
// member pass 2 left unloaded yet defining a name some other object
// already `defined` is exactly the cross-package collision archive
// selective-pull would silently skip. lookup (never intern) keeps
// the pull machinery untouched → byte-id-neutral on every clean
// link. Pulled-member and direct-`.o` dups stay caught in loadimage.
// ww has no weak symbols → a genuine dup. (The bare message matches
// loadimage's; the w6l path+name text divergence is #61, separate.)
let dm: *armember = head;
for (dm != nil) {
if (dm.loaded == 0) {
let de: *defent = dm.defs;
for (de != nil) {
let s: *lsym = lookup(l, de.name);
if (s != nil) {
if (s.defined != 0) {
let msg: str = "w6l: duplicate symbol\n";
os.write(2, msg.ptr, msg.len: u64);
l.errs += 1;
};
};
de = de.dnext;
};
};
dm = dm.mnext;
};
return 0;
};
// ---- main loader -------------------------------------------------------
export fn load(l: *lnk, path: *u8) i32 = {
let bufp: *u8;
let buflen: u64;
bufp, buflen = slurp(path);
if (bufp == nil) {
let m: str = "w6l: cannot read object\n";
os.write(2, m.ptr, m.len: u64);
return -1;
};
if (isarchive(bufp, buflen)) {
return loadarchive(l, path, bufp, buflen);
};
return loadimage(l, path, bufp, buflen);
};
fn loadimage(l: *lnk, path: *u8, buf: *u8, len: u64) i32 = {
if (len < EHDR_SIZE) { return -1; };
// magic: 0x7f, 'E', 'L', 'F'
if (buf[0u64] != 127u8) { return -1; };
if (buf[1u64] != 'E') { return -1; };
if (buf[2u64] != 'L') { return -1; };
if (buf[3u64] != 'F') { return -1; };
if (buf[4u64] != 2u8) { return -1; }; // ELFCLASS64
if (rdu16(buf, EHDR_TYPE) != ET_REL: u16) { return -1; };
if (rdu16(buf, EHDR_MACHINE) != EM_X86_64: u16) { return -1; };
let shoff: u64 = rdu64(buf, EHDR_SHOFF);
let shnum: u32 = rdu16(buf, EHDR_SHNUM): u32;
let shstrndx: u32 = rdu16(buf, EHDR_SHSTRNDX): u32;
let shstrshoff: u64 = rdu64(buf, shoff + (shstrndx: u64) * SHDR_SIZE + SHDR_OFFSET);
let shstr: *u8 = buf + shstrshoff;
// find .text, .data, .symtab, .rela.text, .rela.data
let idxtext: i32 = -1;
let idxdata: i32 = -1;
let idxsymtab: i32 = -1;
let idxrela: i32 = -1;
let idxrelad: i32 = -1;
let i: u32 = 0u32;
for (i < shnum) {
let secoff: u64 = shoff + (i: u64) * SHDR_SIZE;
let shtype: u32 = rdu32(buf, secoff + SHDR_TYPE);
let shname: u32 = rdu32(buf, secoff + SHDR_NAME);
let nm: *u8 = shstr + (shname: u64);
if (shtype == SHT_PROGBITS: u32) {
if (cstreq(nm, ".text")) { idxtext = i: i32; };
if (cstreq(nm, ".data")) { idxdata = i: i32; };
};
if (shtype == SHT_SYMTAB: u32) { idxsymtab = i: i32; };
if (shtype == SHT_RELA: u32) {
if (cstreq(nm, ".rela.text")) { idxrela = i: i32; };
if (cstreq(nm, ".rela.data")) { idxrelad = i: i32; };
};
i += 1u32;
};
if (idxtext < 0) {
let m: str = "w6l: missing .text\n";
os.write(2, m.ptr, m.len: u64);
return -1;
};
if (idxsymtab < 0) {
let m: str = "w6l: missing .symtab\n";
os.write(2, m.ptr, m.len: u64);
return -1;
};
let textsh: u64 = shoff + (idxtext: u64) * SHDR_SIZE;
let textoff: u64 = rdu64(buf, textsh + SHDR_OFFSET);
let textsize: u64 = rdu64(buf, textsh + SHDR_SIZE_F);
let symsh: u64 = shoff + (idxsymtab: u64) * SHDR_SIZE;
let symoff: u64 = rdu64(buf, symsh + SHDR_OFFSET);
let symsize: u64 = rdu64(buf, symsh + SHDR_SIZE_F);
let symlink: u32 = rdu32(buf, symsh + SHDR_LINK);
let nsyms: u64 = symsize / SYM_SIZE;
let strsh: u64 = shoff + (symlink: u64) * SHDR_SIZE;
let stroff: u64 = rdu64(buf, strsh + SHDR_OFFSET);
let strtab: *u8 = buf + stroff;
let datasize: u64 = 0u64;
let dataoff: u64 = 0u64;
if (idxdata >= 0) {
let datash: u64 = shoff + (idxdata: u64) * SHDR_SIZE;
dataoff = rdu64(buf, datash + SHDR_OFFSET);
datasize = rdu64(buf, datash + SHDR_SIZE_F);
};
// Track this object.
let ob: *lobj = alloc(lobj {
path = cstrtostr(path),
buf = buf,
len = len,
textoff = l.textlen,
textsize = textsize,
dataoff = l.datalen,
datasize = datasize,
onext = l.objs,
})!;
l.objs = ob;
// Append .text bytes to the combined image.
emittext(l, buf + textoff, textsize);
// Append .data bytes (if present) to the combined .data buffer.
if (idxdata >= 0) {
if (datasize > 0u64) {
emitdata(l, buf + dataoff, datasize);
};
};
// Walk symbols. We don't keep a per-object map[] of *lsym. Instead
// the reloc loop re-walks symtab and re-interns by name. Simpler
// than dancing around the cgen's u64-shift gaps.
let si: u64 = 1u64; // skip index 0 (always undef sentinel)
for (si < nsyms) {
let symp: u64 = symoff + si * SYM_SIZE;
let stname: u32 = rdu32(buf, symp + SYM_NAME);
let stshndx: u16 = rdu16(buf, symp + SYM_SHNDX);
let stvalue: u64 = rdu64(buf, symp + SYM_VALUE);
let nmp: *u8 = strtab + (stname: u64);
if (nmp[0u64] != 0u8) {
let nm: str = cstrtostr(nmp);
let gs: *lsym = intern(l, nm);
if (stshndx != 0u16) {
let intext: bool = (stshndx: i32) == idxtext;
let indt: bool = false;
if (idxdata >= 0) {
indt = (stshndx: i32) == idxdata;
};
if (intext && indt) { indt = false; };
if (intext) {
if (gs.defined != 0) {
let m: str = "w6l: duplicate symbol\n";
os.write(2, m.ptr, m.len: u64);
l.errs += 1;
} else {
gs.defined = 1;
gs.owner = ob;
gs.idxinowner = si: i32;
gs.val = ob.textoff + stvalue;
};
};
if (indt) {
if (gs.defined != 0) {
let m: str = "w6l: duplicate symbol\n";
os.write(2, m.ptr, m.len: u64);
l.errs += 1;
} else {
gs.defined = 1;
gs.indata = 1;
gs.owner = ob;
gs.idxinowner = si: i32;
gs.val = ob.dataoff + stvalue;
};
};
};
};
si += 1u64;
};
// Per-object relocation collection.
if (idxrela >= 0) {
let relash: u64 = shoff + (idxrela: u64) * SHDR_SIZE;
let relaoff: u64 = rdu64(buf, relash + SHDR_OFFSET);
let relasize: u64 = rdu64(buf, relash + SHDR_SIZE_F);
let nrel: u64 = relasize / RELA_SIZE;
let ri: u64 = 0u64;
for (ri < nrel) {
let rp: u64 = relaoff + ri * RELA_SIZE;
let roff: u64 = rdu64(buf, rp + RELA_OFFSET);
let rinfo: u64 = rdu64(buf, rp + RELA_INFO);
let raddend: u64 = rdu64(buf, rp + RELA_ADDEND);
let rsymidx: u32 = (rinfo >> 32u64): u32;
let rkind: i32 = ((rinfo & 4294967295u64): u32): i32;
let nr: *lrel = alloc(lrel {
off = ob.textoff + roff,
section = 0,
kind = rkind,
addend = raddend: i64,
rnext = l.rels,
})!;
// Look up the referenced sym by name (re-walk symtab).
if ((rsymidx: u64) < nsyms) {
let sp: u64 = symoff + (rsymidx: u64) * SYM_SIZE;
let sname: u32 = rdu32(buf, sp + SYM_NAME);
let snm: *u8 = strtab + (sname: u64);
if (snm[0u64] != 0u8) {
let nm: str = cstrtostr(snm);
nr.sym = intern(l, nm);
};
};
l.rels = nr;
ri += 1u64;
};
};
// Data-reloc collection. Offsets land in .data, shifted by
// this object's data_off so they index the combined buffer.
if (idxrelad >= 0) {
let relash: u64 = shoff + (idxrelad: u64) * SHDR_SIZE;
let relaoff: u64 = rdu64(buf, relash + SHDR_OFFSET);
let relasize: u64 = rdu64(buf, relash + SHDR_SIZE_F);
let nrel: u64 = relasize / RELA_SIZE;
let ri: u64 = 0u64;
for (ri < nrel) {
let rp: u64 = relaoff + ri * RELA_SIZE;
let roff: u64 = rdu64(buf, rp + RELA_OFFSET);
let rinfo: u64 = rdu64(buf, rp + RELA_INFO);
let raddend: u64 = rdu64(buf, rp + RELA_ADDEND);
let rsymidx: u32 = (rinfo >> 32u64): u32;
let rkind: i32 = ((rinfo & 4294967295u64): u32): i32;
let nr: *lrel = alloc(lrel {
off = ob.dataoff + roff,
section = 1,
kind = rkind,
addend = raddend: i64,
rnext = l.rels,
})!;
if ((rsymidx: u64) < nsyms) {
let sp: u64 = symoff + (rsymidx: u64) * SYM_SIZE;
let sname: u32 = rdu32(buf, sp + SYM_NAME);
let snm: *u8 = strtab + (sname: u64);
if (snm[0u64] != 0u8) {
let nm: str = cstrtostr(snm);
nr.sym = intern(l, nm);
};
};
l.rels = nr;
ri += 1u64;
};
};
return 0;
};