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Diffstat (limited to 'src/cmd/ld/ldelf.c')
-rw-r--r--src/cmd/ld/ldelf.c237
1 files changed, 164 insertions, 73 deletions
diff --git a/src/cmd/ld/ldelf.c b/src/cmd/ld/ldelf.c
index bd4f3e7d8..2bbf4f83e 100644
--- a/src/cmd/ld/ldelf.c
+++ b/src/cmd/ld/ldelf.c
@@ -308,9 +308,19 @@ uchar ElfMagic[4] = { 0x7F, 'E', 'L', 'F' };
static ElfSect* section(ElfObj*, char*);
static int map(ElfObj*, ElfSect*);
-static int readsym(ElfObj*, int i, ElfSym*);
+static int readsym(ElfObj*, int i, ElfSym*, int);
static int reltype(char*, int, uchar*);
+int
+valuecmp(Sym *a, Sym *b)
+{
+ if(a->value < b->value)
+ return -1;
+ if(a->value > b->value)
+ return +1;
+ return 0;
+}
+
void
ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
{
@@ -327,8 +337,10 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
Endian *e;
Reloc *r, *rp;
Sym *s;
+ Sym **symbols;
+
+ symbols = nil;
- USED(pkg);
if(debug['v'])
Bprint(&bso, "%5.2f ldelf %s\n", cputime(), pn);
@@ -516,7 +528,7 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
if(sect->type != ElfSectNobits && map(obj, sect) < 0)
goto bad;
- name = smprint("%s(%s)", pn, sect->name);
+ name = smprint("%s(%s)", pkg, sect->name);
s = lookup(name, version);
free(name);
switch((int)sect->flags&(ElfSectFlagAlloc|ElfSectFlagWrite|ElfSectFlagExec)) {
@@ -539,15 +551,99 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
}
s->size = sect->size;
s->align = sect->align;
+ sect->sym = s;
+ }
+
+ // enter sub-symbols into symbol table.
+ // symbol 0 is the null symbol.
+ symbols = malloc(obj->nsymtab * sizeof(symbols[0]));
+ if(symbols == nil) {
+ diag("out of memory");
+ errorexit();
+ }
+ for(i=1; i<obj->nsymtab; i++) {
+ if(readsym(obj, i, &sym, 1) < 0)
+ goto bad;
+ symbols[i] = sym.sym;
+ if(sym.type != ElfSymTypeFunc && sym.type != ElfSymTypeObject && sym.type != ElfSymTypeNone)
+ continue;
+ if(sym.shndx == ElfSymShnCommon) {
+ s = sym.sym;
+ if(s->size < sym.size)
+ s->size = sym.size;
+ if(s->type == 0 || s->type == SXREF)
+ s->type = SBSS;
+ continue;
+ }
+ if(sym.shndx >= obj->nsect || sym.shndx == 0)
+ continue;
+ // even when we pass needSym == 1 to readsym, it might still return nil to skip some unwanted symbols
+ if(sym.sym == S)
+ continue;
+ sect = obj->sect+sym.shndx;
+ if(sect->sym == nil) {
+ diag("%s: sym#%d: ignoring %s in section %d (type %d)", pn, i, sym.name, sym.shndx, sym.type);
+ continue;
+ }
+ s = sym.sym;
+ if(s->outer != S) {
+ if(s->dupok)
+ continue;
+ diag("%s: duplicate symbol reference: %s in both %s and %s", pn, s->name, s->outer->name, sect->sym->name);
+ errorexit();
+ }
+ s->sub = sect->sym->sub;
+ sect->sym->sub = s;
+ s->type = sect->sym->type | (s->type&~SMASK) | SSUB;
+ if(!s->dynexport) {
+ s->dynimplib = nil; // satisfy dynimport
+ s->dynimpname = nil; // satisfy dynimport
+ }
+ s->value = sym.value;
+ s->size = sym.size;
+ s->outer = sect->sym;
+ if(sect->sym->type == STEXT) {
+ Prog *p;
+
+ if(s->text != P) {
+ if(!s->dupok)
+ diag("%s: duplicate definition of %s", pn, s->name);
+ } else {
+ // build a TEXT instruction with a unique pc
+ // just to make the rest of the linker happy.
+ p = prg();
+ p->as = ATEXT;
+ p->from.type = D_EXTERN;
+ p->from.sym = s;
+ p->textflag = 7;
+ p->to.type = D_CONST;
+ p->link = nil;
+ p->pc = pc++;
+ s->text = p;
+ }
+ }
+ }
+
+ // Sort outer lists by address, adding to textp.
+ // This keeps textp in increasing address order.
+ for(i=0; i<obj->nsect; i++) {
+ s = obj->sect[i].sym;
+ if(s == S)
+ continue;
+ if(s->sub)
+ s->sub = listsort(s->sub, valuecmp, offsetof(Sym, sub));
if(s->type == STEXT) {
if(etextp)
etextp->next = s;
else
textp = s;
etextp = s;
+ for(s = s->sub; s != S; s = s->sub) {
+ etextp->next = s;
+ etextp = s;
+ }
}
- sect->sym = s;
- }
+ }
// load relocations
for(i=0; i<obj->nsect; i++) {
@@ -588,14 +684,24 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
p += 4;
}
}
- if(readsym(obj, info>>32, &sym) < 0)
- goto bad;
- if(sym.sym == nil) {
- werrstr("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d",
- sect->sym->name, j, (int)(info>>32), sym.name, sym.shndx, sym.type);
- goto bad;
+ if((info & 0xffffffff) == 0) { // skip R_*_NONE relocation
+ j--;
+ n--;
+ continue;
+ }
+ if((info >> 32) == 0) { // absolute relocation, don't bother reading the null symbol
+ rp->sym = S;
+ } else {
+ if(readsym(obj, info>>32, &sym, 0) < 0)
+ goto bad;
+ sym.sym = symbols[info>>32];
+ if(sym.sym == nil) {
+ werrstr("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d",
+ sect->sym->name, j, (int)(info>>32), sym.name, sym.shndx, sym.type);
+ goto bad;
+ }
+ rp->sym = sym.sym;
}
- rp->sym = sym.sym;
rp->type = reltype(pn, (uint32)info, &rp->siz);
if(rela)
rp->add = add;
@@ -615,65 +721,13 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
s->r = r;
s->nr = n;
}
+ free(symbols);
- // enter sub-symbols into symbol table.
- // symbol 0 is the null symbol.
- for(i=1; i<obj->nsymtab; i++) {
- if(readsym(obj, i, &sym) < 0)
- goto bad;
- if(sym.type != ElfSymTypeFunc && sym.type != ElfSymTypeObject && sym.type != ElfSymTypeNone)
- continue;
- if(sym.shndx == ElfSymShnCommon) {
- s = sym.sym;
- if(s->size < sym.size)
- s->size = sym.size;
- if(s->type == 0 || s->type == SXREF)
- s->type = SBSS;
- continue;
- }
- if(sym.shndx >= obj->nsect || sym.shndx == 0)
- continue;
- sect = obj->sect+sym.shndx;
- if(sect->sym == nil) {
- diag("%s: sym#%d: ignoring %s in section %d (type %d)", pn, i, sym.name, sym.shndx, sym.type);
- continue;
- }
- s = sym.sym;
- s->sub = sect->sym->sub;
- sect->sym->sub = s;
- s->type = sect->sym->type | SSUB;
- if(!s->dynexport) {
- s->dynimplib = nil; // satisfy dynimport
- s->dynimpname = nil; // satisfy dynimport
- }
- s->value = sym.value;
- s->size = sym.size;
- s->outer = sect->sym;
- if(sect->sym->type == STEXT) {
- Prog *p;
-
- if(s->text != P)
- diag("%s: duplicate definition of %s", pn, s->name);
- // build a TEXT instruction with a unique pc
- // just to make the rest of the linker happy.
- p = prg();
- p->as = ATEXT;
- p->from.type = D_EXTERN;
- p->from.sym = s;
- p->textflag = 7;
- p->to.type = D_CONST;
- p->link = nil;
- p->pc = pc++;
- s->text = p;
-
- etextp->next = s;
- etextp = s;
- }
- }
return;
bad:
diag("%s: malformed elf file: %r", pn);
+ free(symbols);
}
static ElfSect*
@@ -707,7 +761,7 @@ map(ElfObj *obj, ElfSect *sect)
}
static int
-readsym(ElfObj *obj, int i, ElfSym *sym)
+readsym(ElfObj *obj, int i, ElfSym *sym, int needSym)
{
Sym *s;
@@ -715,6 +769,9 @@ readsym(ElfObj *obj, int i, ElfSym *sym)
werrstr("invalid elf symbol index");
return -1;
}
+ if(i == 0) {
+ diag("readym: read null symbol!");
+ }
if(obj->is64) {
ElfSymBytes64 *b;
@@ -743,8 +800,6 @@ readsym(ElfObj *obj, int i, ElfSym *sym)
s = nil;
if(strcmp(sym->name, "_GLOBAL_OFFSET_TABLE_") == 0)
sym->name = ".got";
- if(strcmp(sym->name, "__stack_chk_fail_local") == 0)
- sym->other = 0; // rewrite hidden -> default visibility
switch(sym->type) {
case ElfSymTypeSection:
s = obj->sect[sym->shndx].sym;
@@ -754,13 +809,37 @@ readsym(ElfObj *obj, int i, ElfSym *sym)
case ElfSymTypeNone:
switch(sym->bind) {
case ElfSymBindGlobal:
- if(sym->other != 2) {
+ if(needSym) {
s = lookup(sym->name, 0);
- break;
+ // for global scoped hidden symbols we should insert it into
+ // symbol hash table, but mark them as hidden.
+ // __i686.get_pc_thunk.bx is allowed to be duplicated, to
+ // workaround that we set dupok.
+ // TODO(minux): correctly handle __i686.get_pc_thunk.bx without
+ // set dupok generally. See http://codereview.appspot.com/5823055/
+ // comment #5 for details.
+ if(s && sym->other == 2) {
+ s->type |= SHIDDEN;
+ s->dupok = 1;
+ }
}
- // fall through
+ break;
case ElfSymBindLocal:
- s = lookup(sym->name, version);
+ if(!(thechar == '5' && (strcmp(sym->name, "$a") == 0 || strcmp(sym->name, "$d") == 0))) // binutils for arm generate these mapping symbols, ignore these
+ if(needSym) {
+ // local names and hidden visiblity global names are unique
+ // and should only reference by its index, not name, so we
+ // don't bother to add them into hash table
+ s = newsym(sym->name, version);
+ s->type |= SHIDDEN;
+ }
+ break;
+ case ElfSymBindWeak:
+ if(needSym) {
+ s = newsym(sym->name, 0);
+ if(sym->other == 2)
+ s->type |= SHIDDEN;
+ }
break;
default:
werrstr("%s: invalid symbol binding %d", sym->name, sym->bind);
@@ -797,6 +876,18 @@ reltype(char *pn, int elftype, uchar *siz)
switch(R(thechar, elftype)) {
default:
diag("%s: unknown relocation type %d; compiled without -fpic?", pn, elftype);
+ case R('5', R_ARM_ABS32):
+ case R('5', R_ARM_GOT32):
+ case R('5', R_ARM_PLT32):
+ case R('5', R_ARM_GOTOFF):
+ case R('5', R_ARM_GOTPC):
+ case R('5', R_ARM_THM_PC22):
+ case R('5', R_ARM_REL32):
+ case R('5', R_ARM_CALL):
+ case R('5', R_ARM_V4BX):
+ case R('5', R_ARM_GOT_PREL):
+ case R('5', R_ARM_PC24):
+ case R('5', R_ARM_JUMP24):
case R('6', R_X86_64_PC32):
case R('6', R_X86_64_PLT32):
case R('6', R_X86_64_GOTPCREL):
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 07:15:20 +0000