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?l: remove direct hunk manipulation from linkers, just call malloc()

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as with recent changes, cc's malloc() could make the hunk pointer
misaligned. in the the compilers, the hunk pointer is used directly
by the lexer with no effort to to keep the hunk pointer aligned.

alloc/malloc still return aligned pointers, but hunk itself can
be on a odd address after allocation of a odd sized amount of bytes.

however, in the linkers, this assumption appears to be differnet. as
most allocations mostly allocate padded structures. however, symbol
lookup allocates strings on byte-size ganularity and the cc's malloc
would misalign the hunk pointer after the malloc() call. while the
rest of the code assumed hunk pointer was always aligned.

this change removes all the hunk pointer fiddling from the linker,
and we just call malloc() (which will use the fast implmenentation
of cc, and should not really make much of a performance difference).
This commit is contained in:
cinap_lenrek 2020-05-12 22:04:30 +02:00
parent 73f38fc546
commit ecdf3f921e
10 changed files with 40 additions and 259 deletions
Download patch file Download diff file Expand all files Collapse all files

30
sys/src/cmd/1l/obj.c
View file

@ -498,12 +498,7 @@ dosym:
}
}
while(nhunk < sizeof(Auto))
gethunk();
u = (Auto*)hunk;
nhunk -= sizeof(Auto);
hunk += sizeof(Auto);
u = malloc(sizeof(Auto));
u->link = curauto;
curauto = u;
u->asym = s;
@ -760,12 +755,7 @@ loop:
goto loop;
}
while(nhunk < sizeof(Prog))
gethunk();
p = (Prog*)hunk;
nhunk -= sizeof(Prog);
hunk += sizeof(Prog);
p = malloc(sizeof(Prog));
p->as = o;
p->line = bloc[2] | (bloc[3] << 8) | (bloc[4] << 16) | (bloc[5] << 24);
p->back = 2;
@ -1025,12 +1015,7 @@ lookup(char *symb, int v)
if(memcmp(s->name, symb, l) == 0)
return s;
while(nhunk < sizeof(Sym))
gethunk();
s = (Sym*)hunk;
nhunk -= sizeof(Sym);
hunk += sizeof(Sym);
s = malloc(sizeof(Sym));
s->name = malloc(l + 1);
memmove(s->name, symb, l);
@ -1046,14 +1031,7 @@ lookup(char *symb, int v)
Prog*
prg(void)
{
Prog *p;
while(nhunk < sizeof(Prog))
gethunk();
p = (Prog*)hunk;
nhunk -= sizeof(Prog);
hunk += sizeof(Prog);
Prog *p = (Prog*)malloc(sizeof(Prog));
*p = zprg;
return p;
}