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).
102 lines
2.4 KiB
Plaintext
102 lines
2.4 KiB
Plaintext
// selfhost/cmd/6l/sym.ww — port of cmd/6l/sym.c.
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//
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// Linker symbol table. Singly-linked list, usually a few hundred
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// entries; hashing isn't worth it yet.
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use mem;
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type lsym = struct {
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name: str,
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val: u64, // offset within combined .text once linked
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defined: i32, // 1 if some lobj defines this symbol
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owner: *lobj,
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idx_in_owner: i32,
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// Dynamic-linking fields. Set by l_resolve when an undefined sym
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// is provided by some loaded lso. plt_idx and dynsym_idx default
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// to -1 (set explicitly by l_resolve, not by amalloc-zeroing).
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is_dyn: i32,
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dyn_lib: *lso,
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dyn_version: str, // matched export's version; len 0 if none
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plt_idx: i32,
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dynsym_idx: i32,
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snext: *lsym,
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};
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type lrel = struct {
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off: u64, // offset within combined .text
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kind: i32, // R_X86_64_*
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sym: *lsym,
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addend: i64,
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rnext: *lrel,
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};
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type lobj = struct {
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path: str,
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buf: *u8, // object bytes
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len: u64,
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text_off: u64, // offset of .text in combined output
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text_size: u64,
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onext: *lobj,
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};
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// lexport — one entry per GLOBAL/WEAK symbol exported by a loaded .so.
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// Stored as a chain in the order the .so's dynsym presents them, so
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// l_so_provides_v's first-match semantics agree with the C version.
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type lexport = struct {
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name: str,
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version: str, // len 0 for unversioned globals
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enext: *lexport,
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};
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type lso = struct {
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path: str, // full filesystem path used to load
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soname: str, // DT_SONAME, or basename if missing
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exports: *lexport, // dynsym-order chain of exported names
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sonext: *lso,
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};
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type lnk = struct {
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a: *arena,
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objs: *lobj,
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sos: *lso,
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syms: *lsym,
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rels: *lrel,
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text: *u8, // combined .text
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textcap: u64,
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textlen: u64,
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errs: i32,
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dyn_n: i32, // number of syms routed through PLT
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};
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fn streq(a: str, b: str) bool = {
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if (a.len != b.len) { return false; };
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let i: i32 = 0;
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for (i < a.len) {
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if (a[i] != b[i]) { return false; };
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i += 1;
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};
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return true;
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};
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export fn l_intern(l: *lnk, name: str) *lsym = {
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let s: *lsym = l.syms;
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for (s != nil) {
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if (streq(s.name, name)) { return s; };
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s = s.snext;
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};
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let n: *lsym = amalloc(l.a, 96u64): *lsym;
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n.name = name;
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n.snext = l.syms;
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l.syms = n;
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return n;
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};
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export fn l_lookup(l: *lnk, name: str) *lsym = {
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let s: *lsym = l.syms;
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for (s != nil) {
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if (streq(s.name, name)) { return s; };
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s = s.snext;
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};
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return nil;
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};
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