tccgen: arm/i386: save_reg_upstack

tccgen.c:gv() when loading long long from lvalue, before
was saving all registers which caused problems in the arm
function call register parameter preparation, as with

    void foo(long long y, int x);
    int main(void)
    {
      unsigned int *xx[1], x;
      unsigned long long *yy[1], y;
      foo(**yy, **xx);
      return 0;
    }

Now only the modified register is saved if necessary,
as in this case where it is used to store the result
of the post-inc:

        long long *p, v, **pp;
        v = 1;
        p = &v;
        p[0]++;
        printf("another long long spill test : %lld\n", *p);

i386-gen.c :
- found a similar problem with TOK_UMULL caused by the
  vstack juggle in tccgen:gen_opl()
  (bug seen only when using EBX as 4th register)
This commit is contained in:
grischka 2016-10-04 17:36:51 +02:00
parent 1c4cf18556
commit b691585785
5 changed files with 42 additions and 23 deletions

View File

@ -1177,7 +1177,8 @@ again:
}
}
/* second pass to restore registers that were saved on stack by accident */
/* second pass to restore registers that were saved on stack by accident.
Maybe redundant after the "lvalue_save" patch in tccgen.c:gv() */
if (++pass < 2)
goto again;

View File

@ -848,6 +848,8 @@ ST_FUNC void gen_opi(int op)
fr = vtop[0].r;
vtop--;
save_reg(TREG_EDX);
/* save EAX too if used otherwise */
save_reg_upstack(TREG_EAX, 1);
if (op == TOK_UMULL) {
o(0xf7); /* mul fr */
o(0xe0 + fr);

1
tcc.h
View File

@ -1295,6 +1295,7 @@ ST_FUNC void lexpand_nr(void);
#endif
ST_FUNC void vpushv(SValue *v);
ST_FUNC void save_reg(int r);
ST_FUNC void save_reg_upstack(int r, int n);
ST_FUNC int get_reg(int rc);
ST_FUNC void save_regs(int n);
ST_FUNC void gaddrof(void);

View File

@ -533,17 +533,35 @@ static void vdup(void)
vpushv(vtop);
}
/* save registers up to (vtop - n) stack entry */
ST_FUNC void save_regs(int n)
{
SValue *p, *p1;
for(p = vstack, p1 = vtop - n; p <= p1; p++)
save_reg(p->r);
}
/* save r to the memory stack, and mark it as being free */
ST_FUNC void save_reg(int r)
{
save_reg_upstack(r, 0);
}
/* save r to the memory stack, and mark it as being free,
if seen up to (vtop - n) stack entry */
ST_FUNC void save_reg_upstack(int r, int n)
{
int l, saved, size, align;
SValue *p, sv;
SValue *p, *p1, sv;
CType *type;
if ((r &= VT_VALMASK) >= VT_CONST)
return;
/* modify all stack values */
saved = 0;
l = 0;
for(p=vstack;p<=vtop;p++) {
for(p = vstack, p1 = vtop - n; p <= p1; p++) {
if ((p->r & VT_VALMASK) == r ||
((p->type.t & VT_BTYPE) == VT_LLONG && (p->r2 & VT_VALMASK) == r)) {
/* must save value on stack if not already done */
@ -659,20 +677,6 @@ ST_FUNC int get_reg(int rc)
return -1;
}
/* save registers up to (vtop - n) stack entry */
ST_FUNC void save_regs(int n)
{
int r;
SValue *p, *p1;
p1 = vtop - n;
for(p = vstack;p <= p1; p++) {
r = p->r & VT_VALMASK;
if (r < VT_CONST) {
save_reg(r);
}
}
}
/* move register 's' (of type 't') to 'r', and flush previous value of r to memory
if needed */
static void move_reg(int r, int s, int t)
@ -859,13 +863,17 @@ ST_FUNC int gv(int rc)
vpushi(ll >> 32); /* second word */
} else
#endif
if (r >= VT_CONST || /* XXX: test to VT_CONST incorrect ? */
(vtop->r & VT_LVAL)) {
if (vtop->r & VT_LVAL) {
/* We do not want to modifier the long long
pointer here, so the safest (and less
efficient) is to save all the other registers
in the stack. XXX: totally inefficient. */
#if 0
save_regs(1);
#else
/* lvalue_save: save only if used further down the stack */
save_reg_upstack(vtop->r, 1);
#endif
/* load from memory */
vtop->type.t = load_type;
load(r, vtop);

View File

@ -1953,6 +1953,11 @@ long long int value(struct S *v)
return ((long long int)v->item);
}
long long llfunc2(long long x, long long y, int z)
{
return x * y * z;
}
void longlong_test(void)
{
long long a, b, c;
@ -1999,15 +2004,17 @@ void longlong_test(void)
}
lloptest(0x80000000, 0);
/* another long long spill test */
{
long long *p, v;
long long *p, v, **pp;
v = 1;
p = &v;
p[0]++;
printf("%lld\n", *p);
}
printf("another long long spill test : %lld\n", *p);
pp = &p;
v = llfunc2(**pp, **pp, ia);
printf("a long long function (arm-)reg-args test : %lld\n", v);
}
a = 68719476720LL;
b = 4294967295LL;
printf("%d %d %d %d\n", a > b, a < b, a >= b, a <= b);