101 lines
2.6 KiB
Plaintext
101 lines
2.6 KiB
Plaintext
// selfhost/cmd/w6l/sym.ww — port of cmd/w6l/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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package w6l;
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import strings;
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type lsym = struct {
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name: str,
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val: u64, // offset within combined .text (or .data when
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// indata=1) once linked
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defined: i32, // 1 if some lobj defines this symbol
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indata: i32, // 1 if defined in .data (writable globals)
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owner: *lobj,
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idxinowner: i32,
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// Dynamic-linking fields. Set by resolve when an undefined sym
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// is provided by some loaded lso. pltidx and dynsymidx default
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// to -1 (set explicitly by resolve; alloc-zeroing gives 0, not -1).
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isdyn: i32,
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dynlib: *lso,
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dynversion: str, // matched export's version; len 0 if none
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pltidx: i32,
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dynsymidx: 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 the relocation's section
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section: i32, // 0 = .text, 1 = .data
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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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textoff: u64, // offset of .text in combined output
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textsize: u64,
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dataoff: u64, // offset of .data in combined output
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datasize: u64, // bytes contributed to combined .data (0 if none)
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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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// soprovides_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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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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// Combined .data (writable). Empty unless any input .o has a
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// .data PROGBITS section.
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data: *u8,
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datacap: u64,
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datalen: u64,
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errs: i32,
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dynn: i32, // number of syms routed through PLT
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};
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export fn 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 (strings.compare(s.name, name) == 0) { return s; };
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s = s.snext;
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};
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let n: *lsym = alloc(lsym { name = name, 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 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 (strings.compare(s.name, name) == 0) { 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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