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reloc.c
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reloc.c
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/* reloc.c - relocation support functions */
/* (c) in 2010-2016,2020,2022,2023 by Volker Barthelmann and Frank Wille */
#include "vasm.h"
nreloc *new_nreloc(void)
{
nreloc *new = mymalloc(sizeof(*new));
new->mask = DEFMASK;
new->byteoffset = new->bitoffset = new->size = 0;
new->addend = 0;
return new;
}
rlist *add_extnreloc(rlist **relocs,symbol *sym,taddr addend,int type,
size_t bitoffs,size_t size,size_t byteoffs)
/* add_extnreloc() can specify byteoffset and bitoffset directly.
Use add_nreloc() for the old interface, which calculates
byteoffset and bitoffset from offset. */
{
rlist *rl;
nreloc *r;
if (sym->flags & ABSLABEL)
return NULL; /* no relocation, when symbol is from an ORG-section */
/* mark symbol as referenced, so we can find unreferenced imported symbols */
sym->flags |= REFERENCED;
r = new_nreloc();
r->byteoffset = byteoffs;
r->bitoffset = bitoffs;
r->size = size;
r->sym = sym;
r->addend = addend;
rl = mymalloc(sizeof(rlist));
rl->type = type;
rl->reloc = r;
rl->next = *relocs;
*relocs = rl;
return rl;
}
rlist *add_extnreloc_masked(rlist **relocs,symbol *sym,taddr addend,int type,
size_t bitoffs,size_t size,size_t byteoffs,
utaddr mask)
/* add_extnreloc_masked() can specify byteoffset and bitoffset directly.
Use add_nreloc_masked() for the old interface, which calculates
byteoffset and bitoffset from offset. */
{
rlist *rl;
nreloc *r;
if (rl = add_extnreloc(relocs,sym,addend,type,bitoffs,size,byteoffs)) {
r = rl->reloc;
r->mask = mask;
}
return rl;
}
int is_pc_reloc(symbol *sym,section *cur_sec)
/* Returns true when the symbol needs a REL_PC relocation to reference it
pc-relative. This is the case when it is externally defined or a label
from a different section (so the linker has to resolve the distance). */
{
if (EXTREF(sym))
return 1;
else if (LOCREF(sym))
return (cur_sec->flags & ABSOLUTE) ? 0 : sym->sec != cur_sec;
ierror(0);
return 0;
}
void do_pic_check(rlist *rl)
/* generate an error on a non-PC-relative relocation */
{
nreloc *r;
int t;
while (rl) {
t = rl->type;
if (t==REL_ABS || t==REL_UABS) {
r = (nreloc *)rl->reloc;
if (r->sym->type==LABSYM ||
(r->sym->type==IMPORT && (r->sym->flags&EXPORT)))
general_error(34); /* relocation not allowed */
}
rl = rl->next;
}
}
taddr nreloc_real_addend(nreloc *nrel)
{
/* In vasm the addend includes the symbol's section offset for LABSYMs */
if (nrel->sym->type == LABSYM)
return nrel->addend - nrel->sym->pc;
return nrel->addend;
}
void unsupp_reloc_error(rlist *rl)
{
if (rl->type <= LAST_STANDARD_RELOC) {
nreloc *r = (nreloc *)rl->reloc;
/* reloc type not supported */
output_error(4,rl->type,r->size,(unsigned long)r->mask,
r->sym->name,(unsigned long)r->addend);
}
else
output_error(5,rl->type);
}
void print_reloc(FILE *f,int type,nreloc *p)
{
if (type==REL_NONE)
fprintf(f,"rnone(");
else if (type<=LAST_STANDARD_RELOC){
static const char *rname[] = {
"abs","pc","got","gotrel","gotoff","globdat","plt","pltrel",
"pltoff","sd","uabs","localpc","loadrel","copy","jmpslot","secoff"
};
fprintf(f,"r%s(%u,%u-%u,0x%llx,0x%llx,",rname[type-1],
(unsigned)p->byteoffset,(unsigned)p->bitoffset,
(unsigned)(p->bitoffset+p->size-1),
ULLTADDR(p->mask),ULLTADDR(p->addend));
}
#ifdef VASM_CPU_PPC
else if (type<=LAST_PPC_RELOC){
static const char *rname[] = {
"sd2","sd21","sdi16","drel","brel"
};
fprintf(f,"r%s(%u,%u-%u,0x%llx,0x%llx,",
rname[type-(LAST_STANDARD_RELOC+1)],
(unsigned)p->byteoffset,(unsigned)p->bitoffset,
(unsigned)(p->bitoffset+p->size-1),
ULLTADDR(p->mask),ULLTADDR(p->addend));
}
#endif
else
fprintf(f,"unknown reloc(");
print_symbol(f,p->sym);
fprintf(f,") ");
}
rlist *get_relocs(atom *a)
{
if (a->type == DATA)
return a->content.db->relocs;
else if (a->type == SPACE)
return a->content.sb->relocs;
return NULL;
}
static void *get_nreloc_ptr(atom *a,nreloc *nrel)
{
if (a->type == DATA)
return (char *)a->content.db->data + nrel->byteoffset;
else if (a->type == SPACE)
return (char *)a->content.sb->fill; /* @@@ ignore offset completely? */
return NULL;
}
int patch_nreloc(atom *a,rlist *rl,int signedflag,taddr val,int be)
/* patch relocated value into the atom, when rlist contains an nreloc */
{
nreloc *nrel;
char *p;
if (rl->type > LAST_STANDARD_RELOC) {
unsupp_reloc_error(rl);
return 0;
}
nrel = (nreloc *)rl->reloc;
if (field_overflow(signedflag,nrel->size,val)) {
output_atom_error(12,a,rl->type,(unsigned long)nrel->mask,nrel->sym->name,
(unsigned long)nrel->addend,nrel->size);
return 0;
}
if (p = get_nreloc_ptr(a,nrel)) {
setbits(be,p,(nrel->bitoffset+nrel->size+7)&~7,
nrel->bitoffset,nrel->size,val);
}
return 1;
}