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Factor out the register allocation routines to make them easier to deal with.

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This commit is contained in:
David Given 2016-10-14 23:17:06 +02:00
parent bb53a7fb51
commit a63052427e
1 changed files with 67 additions and 44 deletions
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109
mach/proto/mcg/pass_registerallocator.c
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@ -105,6 +105,61 @@ static bool allocatable(struct hreg* hreg, struct vreg* vreg)
return (hreg->attrs & c->attrs);
}
static struct hreg* find_input_reg(struct vreg* vreg)
{
int i;
struct hreg* hreg = NULL;
for (i=0; i<hregs.count; i++)
{
hreg = hregs.item[i];
if (allocatable(hreg, vreg) &&
!pmap_findleft(current_ins, hreg))
{
return hreg;
}
}
return NULL;
}
static struct hreg* find_output_reg(struct vreg* vreg)
{
int i;
struct hreg* hreg = NULL;
for (i=0; i<hregs.count; i++)
{
hreg = hregs.item[i];
if (allocatable(hreg, vreg) &&
!pmap_findleft(current_outs, hreg))
{
return hreg;
}
}
return NULL;
}
static struct hreg* find_through_reg(struct vreg* vreg)
{
int i;
struct hreg* hreg = NULL;
for (i=0; i<hregs.count; i++)
{
hreg = hregs.item[i];
if (allocatable(hreg, vreg) &&
!pmap_findleft(current_ins, hreg) &&
!pmap_findleft(current_outs, hreg))
{
return hreg;
}
}
return NULL;
}
static void add_input_register(struct vreg* vreg, struct hreg* hreg)
{
int i;
@ -121,21 +176,11 @@ static void add_input_register(struct vreg* vreg, struct hreg* hreg)
/* Find an unused input register of the right class. */
hreg = NULL;
for (i=0; i<hregs.count; i++)
{
hreg = hregs.item[i];
if (allocatable(hreg, vreg) &&
!pmap_findright(current_ins, vreg))
{
/* Got one --- use it. */
pmap_add(current_ins, hreg, vreg);
return;
}
}
hreg = find_input_reg(vreg);
if (!hreg)
hreg = evict(hreg);
/* Um, oops --- ran out of registers. Evict one and try again. */
assert(false);
pmap_add(current_ins, hreg, vreg);
}
static void add_output_register(struct vreg* vreg)
@ -169,45 +214,23 @@ static void add_output_register(struct vreg* vreg)
* way: we try to allocate a matched set of input and output registers.
* */
hreg = NULL;
for (i=0; i<hregs.count; i++)
{
hreg = hregs.item[i];
if (allocatable(hreg, vreg) &&
!pmap_findleft(current_ins, hreg) &&
!pmap_findleft(current_outs, hreg))
{
goto found1;
}
}
/* If we couldn't find one, evict a register. */
hreg = find_through_reg(vreg);
if (!hreg)
hreg = evict(vreg);
found1:
pmap_add(current_outs, hreg, vreg);
tracef('R', "R: output equality constraint requires extra move of %%%d => %s\n",
c->equals_to->id, hreg->name);
pmap_add(current_ins, hreg, c->equals_to);
}
else
{
/* This is an ordinary new register. */
hreg = NULL;
for (i=0; i<hregs.count; i++)
{
hreg = hregs.item[i];
if (allocatable(hreg, vreg) &&
!pmap_findleft(current_outs, hreg))
{
goto found2;
}
}
/* If we couldn't find one, evict a register. */
hreg = find_output_reg(vreg);
if (!hreg)
hreg = evict(vreg);
found2:
pmap_add(current_outs, hreg, vreg);
}
}