Hojun-Cho
1657bdeda3
C bootstrap (phases 0-9):
cmd/wwc, cmd/6c, cmd/6a, cmd/6l, cmd/ww, rt, lib/*.
ww-side self-host (phase 10):
selfhost/cmd/wwc — ww-cgen frontend; bootstrap fixed point.
selfhost/cmd/6a — assembler; byte-identical to C 6a (test 991).
selfhost/cmd/6l — linker w/ archive (.a) support; byte-identical
to C 6l (test 992).
selfhost/cmd/ww — driver (build/run/version); byte-identical to
C ww (test 993).
make test: 15/15. make bootstrap: ww2.s == ww3.s, ww2.o == ww3.o,
ww2 == ww3 byte-identical, with the full ww-tooled chain.
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/*
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* pass.c — resolution + relocation. After all objects are loaded:
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*
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* l_resolve : check that every symbol referenced by a relocation
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* is defined somewhere. Errors get logged.
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* l_relocate: with the final virtual base address known, walk the
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* relocation list and patch the .text bytes in place.
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*
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* Supported relocation kinds: PC32 (2), PLT32 (4). Both are PC-relative
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* 32-bit displacements; for static linking PLT32 collapses to PC32.
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*/
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#include "l.h"
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#include <stdio.h>
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#include <string.h>
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#define R_X86_64_PC32 2
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#define R_X86_64_PLT32 4
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int
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l_resolve(Lnk *l)
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{
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for (Lrel *r = l->rels; r; r = r->next) {
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if (r->sym == NULL) continue;
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if (!r->sym->defined) {
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fprintf(stderr, "6l: undefined reference to '%s'\n",
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r->sym->name);
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l->errs++;
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}
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}
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return l->errs;
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}
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static void
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patch_u32(u8 *p, u32 v)
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{
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p[0] = (u8)(v & 0xff);
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p[1] = (u8)((v >> 8) & 0xff);
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p[2] = (u8)((v >> 16) & 0xff);
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p[3] = (u8)((v >> 24) & 0xff);
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}
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int
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l_relocate(Lnk *l, u64 base)
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{
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for (Lrel *r = l->rels; r; r = r->next) {
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if (r->sym == NULL || !r->sym->defined) continue;
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switch (r->kind) {
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case R_X86_64_PC32:
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case R_X86_64_PLT32: {
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u64 site = base + r->off;
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i64 target = (i64)(base + r->sym->val);
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i64 rel = target - (i64)site + r->addend;
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patch_u32(l->text + r->off, (u32)(i32)rel);
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break;
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}
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default:
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fprintf(stderr, "6l: unsupported reloc kind %d\n",
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r->kind);
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l->errs++;
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}
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}
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return l->errs;
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}
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