Register spilling to the stack frame works, more or less.

This commit is contained in:
David Given 2016-10-15 22:53:56 +02:00
parent 0eb32e7553
commit 7aa60a6451
13 changed files with 242 additions and 51 deletions

View file

@ -52,6 +52,27 @@ void hop_add_value_insel(struct hop* hop, struct ir* ir)
array_append(&hop->insels, insel);
}
void hop_add_st_offset_insel(struct hop* hop, struct hreg* hreg)
{
struct insel* insel = new_insel(INSEL_ST_OFFSET);
insel->u.hreg = hreg;
array_append(&hop->insels, insel);
}
void hop_add_ab_offset_insel(struct hop* hop, int offset)
{
struct insel* insel = new_insel(INSEL_AB_OFFSET);
insel->u.offset = offset;
array_append(&hop->insels, insel);
}
void hop_add_lb_offset_insel(struct hop* hop, int offset)
{
struct insel* insel = new_insel(INSEL_LB_OFFSET);
insel->u.offset = offset;
array_append(&hop->insels, insel);
}
void hop_add_eoi_insel(struct hop* hop)
{
struct insel* insel = new_insel(INSEL_EOI);
@ -74,6 +95,18 @@ void hop_add_insel(struct hop* hop, const char* fmt, ...)
hop_add_string_insel(hop, aprintf("%d", va_arg(ap, int)));
break;
case 'S':
hop_add_st_offset_insel(hop, va_arg(ap, struct hreg*));
break;
case 'A':
hop_add_ab_offset_insel(hop, va_arg(ap, int));
break;
case 'L':
hop_add_lb_offset_insel(hop, va_arg(ap, int));
break;
case 'H':
hop_add_hreg_insel(hop, va_arg(ap, struct hreg*));
break;
@ -193,6 +226,18 @@ char* hop_render(struct hop* hop)
appendf("%s", insel->u.string);
break;
case INSEL_ST_OFFSET:
appendf("(st+%d)", insel->u.hreg->offset);
break;
case INSEL_AB_OFFSET:
appendf("(ab+%d)", insel->u.offset);
break;
case INSEL_LB_OFFSET:
appendf("(lb+%d)", insel->u.offset);
break;
case INSEL_VALUE:
{
struct ir* ir = insel->u.value;

View file

@ -7,6 +7,9 @@ enum insel_type
INSEL_HREG,
INSEL_VREG,
INSEL_VALUE,
INSEL_ST_OFFSET,
INSEL_AB_OFFSET,
INSEL_LB_OFFSET,
INSEL_EOI
};
@ -19,6 +22,7 @@ struct insel
struct hreg* hreg;
struct vreg* vreg;
struct ir* value;
int offset;
}
u;
};
@ -53,6 +57,9 @@ extern void hop_add_string_insel(struct hop* hop, const char* string);
extern void hop_add_hreg_insel(struct hop* hop, struct hreg* hreg);
extern void hop_add_vreg_insel(struct hop* hop, struct vreg* vreg);
extern void hop_add_value_insel(struct hop* hop, struct ir* ir);
extern void hop_add_st_offset_insel(struct hop* hop, struct hreg* hreg);
extern void hop_add_ab_offset_insel(struct hop* hop, int offset);
extern void hop_add_lb_offset_insel(struct hop* hop, int offset);
extern void hop_add_eoi_insel(struct hop* hop);
extern void hop_add_insel(struct hop* hop, const char* fmt, ...);

View file

@ -112,7 +112,7 @@ extern void pass_instruction_selector(void);
extern void pass_live_vreg_analysis(void);
extern void pass_add_prologue_epilogue(struct procedure* proc);
extern void pass_promote_float_ops(struct procedure* proc);
extern void pass_register_allocator(void);
extern void pass_register_allocator(struct procedure* proc);
extern void pass_remove_dead_blocks(struct procedure* proc);
extern void pass_remove_dead_phis(void);
extern void pass_split_critical_edges(struct procedure* proc);
@ -120,6 +120,7 @@ extern void pass_split_critical_edges(struct procedure* proc);
extern struct hop* platform_prologue(struct procedure* proc);
extern struct hop* platform_epilogue(struct procedure* proc);
extern struct hop* platform_move(struct basicblock* bb, struct hreg* src, struct hreg* dest);
extern void platform_calculate_offsets(struct procedure* proc);
extern FILE* outputfile;
extern FILE* dominance_dot_file;

View file

@ -308,7 +308,7 @@ static void parse_pseu(void)
current_proc = calloc(sizeof(struct procedure), 1);
current_proc->name = strdup(em.em_pnam);
current_proc->entry = bb_get(current_proc->name);
current_proc->nlocals = em.em_nlocals;
current_proc->locals_size = em.em_nlocals;
code_bb = current_proc->entry;
code_bb->is_root = true;
array_append(&current_proc->blocks, code_bb);

View file

@ -100,6 +100,26 @@ static void constrain_input_reg(int child, uint32_t attr)
get_constraint(vreg)->attrs = attr;
}
static uint32_t find_type_from_constraint(uint32_t attr)
{
/* Looks through the registers and finds a concrete register implementing
* that attribute, and returns the type. We assume that all registers
* implementing an attribute (which anyone is going to ask for, 'volatile'
* doesn't count) will have the same type. TODO: mcgg should check for
* this. */
const struct burm_register_data* brd = burm_register_data;
while (brd->name)
{
if (brd->attrs & attr)
return brd->type;
brd++;
}
fatal("unable to find a register matching attribute 0x%x", attr);
return 0;
}
static void constrain_output_reg(uint32_t attr)
{
struct vreg* vreg = current_hop->output;
@ -109,6 +129,7 @@ static void constrain_output_reg(uint32_t attr)
array_appendu(&current_hop->outs, vreg);
vreg->defined = current_hop;
vreg->type = find_type_from_constraint(attr);
get_constraint(vreg)->attrs = attr;
}

View file

@ -34,8 +34,9 @@ static void recursively_associate_group(struct phicongruence* c, struct vreg* vr
if (vreg->defined)
{
struct constraint* constraint = pmap_findleft(&vreg->defined->constraints, vreg);
if ((c->attrs == 0) || (constraint->attrs < c->attrs))
c->attrs = constraint->attrs;
if (c->type == 0)
c->type = vreg->type;
assert(c->type == vreg->type);
array_appendu(&c->definitions, vreg->defined);
}

View file

@ -6,6 +6,8 @@ struct assignment
struct vreg* out;
};
static struct procedure* current_proc;
static ARRAYOF(struct hreg) hregs;
static PMAPOF(struct vreg, struct hreg) evicted;
@ -42,7 +44,7 @@ static void wire_up_blocks_ins_outs(void)
}
static struct hreg* allocate_phi_hreg(register_assignment_t* regs,
struct vreg* vreg, uint32_t attrs)
struct vreg* vreg, uint32_t type)
{
int i;
@ -52,7 +54,7 @@ static struct hreg* allocate_phi_hreg(register_assignment_t* regs,
for (i=0; i<hregs.count; i++)
{
struct hreg* hreg = hregs.item[i];
if (!pmap_findleft(regs, hreg) && (hreg->attrs & attrs))
if (!pmap_findleft(regs, hreg) && (hreg->type == type))
{
/* This one is unused. Use it. */
return hreg;
@ -99,19 +101,39 @@ static struct hreg* evict(struct vreg* vreg)
assert(false);
}
static bool allocatable_input(struct hreg* hreg, struct vreg* vreg)
static bool type_match(struct hreg* hreg, struct vreg* vreg)
{
struct constraint* c = pmap_findleft(&current_hop->constraints, vreg);
if (c)
return (hreg->attrs & c->attrs);
if (vreg->congruence)
return (hreg->type == vreg->congruence->type);
return (hreg->type == vreg->type);
}
static bool allocatable_stackable_input(struct hreg* hreg, struct vreg* vreg)
{
return !pmap_findleft(current_ins, hreg) &&
(!c || (hreg->attrs & c->attrs));
type_match(hreg, vreg);
}
static bool allocatable_stackable_output(struct hreg* hreg, struct vreg* vreg)
{
return !pmap_findleft(current_outs, hreg) &&
type_match(hreg, vreg) &&
!(hreg->attrs & current_hop->insndata->corrupts);
}
static bool allocatable_input(struct hreg* hreg, struct vreg* vreg)
{
return allocatable_stackable_input(hreg, vreg) &&
!hreg->is_stacked;
}
static bool allocatable_output(struct hreg* hreg, struct vreg* vreg)
{
struct constraint* c = pmap_findleft(&current_hop->constraints, vreg);
return !pmap_findleft(current_outs, hreg) &&
(!c || (hreg->attrs & c->attrs)) &&
!(hreg->attrs & current_hop->insndata->corrupts);
return allocatable_stackable_output(hreg, vreg) &&
!hreg->is_stacked;
}
static struct hreg* find_input_reg(struct vreg* vreg)
@ -174,7 +196,32 @@ static void add_input_register(struct vreg* vreg, struct hreg* hreg)
if (hreg)
{
if (pmap_findleft(current_ins, hreg) == vreg)
if (hreg->is_stacked)
{
/* This vreg is stacked; we need to put it in a register. That's
* slightly exciting because the vreg might be a through, which
* means we need an output register too... which we might not be
* able to allocate. */
if (array_contains(&current_hop->throughs, vreg))
{
struct hreg* src = hreg;
hreg = find_through_reg(vreg);
assert(hreg);
pmap_remove(current_ins, src, vreg);
pmap_remove(current_outs, src, vreg);
pmap_add(current_ins, hreg, vreg);
pmap_add(current_outs, hreg, vreg);
return;
}
else
{
/* Not a through. */
pmap_remove(current_ins, hreg, vreg);
hreg = NULL;
}
}
else if (pmap_findleft(current_ins, hreg) == vreg)
{
/* Yup, already there. */
}
@ -213,7 +260,7 @@ static void add_output_register(struct vreg* vreg)
c = pmap_findleft(&current_hop->constraints, vreg);
if (c->equals_to)
{
tracef('R', "R: outputput equality constraint of %%%d to %%%d\n",
tracef('R', "R: output equality constraint of %%%d to %%%d\n",
vreg->id, c->equals_to->id);
/* This output register is constrained to be in the same hreg as an
@ -262,28 +309,31 @@ static void add_through_register(struct vreg* vreg, struct hreg* hreg)
if (hreg)
{
bool infree = allocatable_input(hreg, vreg);
bool outfree = allocatable_output(hreg, vreg);
bool infree = allocatable_stackable_input(hreg, vreg);
bool outfree = allocatable_stackable_output(hreg, vreg);
struct vreg* inuse = pmap_findleft(current_ins, hreg);
struct vreg* outuse = pmap_findleft(current_outs, hreg);
if (infree && outfree)
if ((infree || (inuse == vreg)) &&
(outfree || (outuse == vreg)))
{
/* Register unused --- use it. */
}
if ((infree || pmap_findleft(current_ins, hreg) == vreg) &&
(outfree || pmap_findleft(current_outs, hreg) == vreg))
{
/* Input and output are either free or already assigned. */
/* Input and output are either free or already assigned to this
* vreg. */
}
else
{
/* Nope, can't honour the hint. */
hreg = NULL;
/* Nope, can't honour the hint. Mark the register as evicted; we'll
* put it in something later (probably a stack slot). */
tracef('R', "R: cannot place %%%d in %s, evicting\n", vreg->id, hreg->name);
pmap_put(&evicted, vreg, hreg);
pmap_remove(current_ins, hreg, vreg);
pmap_remove(current_outs, hreg, vreg);
return;
}
}
if (!hreg)
hreg = find_through_reg(vreg);
assert(hreg);
pmap_put(current_ins, hreg, vreg);
pmap_put(current_outs, hreg, vreg);
}
@ -302,8 +352,8 @@ static void find_new_home_for_evicted_register(struct vreg* vreg, struct hreg* s
{
hreg = hregs.item[i];
if ((hreg->type == src->type) &&
allocatable_input(hreg, vreg) &&
allocatable_output(hreg, vreg))
allocatable_stackable_input(hreg, vreg) &&
allocatable_stackable_output(hreg, vreg))
{
goto found;
}
@ -311,7 +361,8 @@ static void find_new_home_for_evicted_register(struct vreg* vreg, struct hreg* s
/* No more registers --- allocate a stack slot. */
assert(false);
hreg = new_stacked_hreg(src->type);
array_append(&hregs, hreg);
found:
tracef('R', "R: evicted %%%d moving to %s\n", vreg->id, hreg->name);
@ -442,7 +493,7 @@ static void assign_hregs_to_vregs(void)
if (!pmap_findright(old, vreg))
{
struct phicongruence* c = vreg->congruence;
struct hreg* hreg = allocate_phi_hreg(old, vreg, c->attrs);
struct hreg* hreg = allocate_phi_hreg(old, vreg, c->type);
tracef('R', "R: import fallback hreg %s for phi input %%%d from %s\n",
hreg->name, vreg->id, phi->prev->name);
@ -552,6 +603,7 @@ static int insert_moves(struct basicblock* bb, int index,
{
/* Swap. */
assert(false);
src = copies.item[0].left;
dest = pmap_findleft(&copies, src);
hop = create_swap(bb, src, dest);
@ -626,13 +678,43 @@ static void insert_phi_copies(void)
}
}
void pass_register_allocator(void)
static int pack_stackframe(int stacksize, int size, uint32_t attr)
{
int i;
for (i=0; i<hregs.count; i++)
{
struct hreg* hreg = hregs.item[i];
if (hreg->is_stacked && (hreg->type & attr))
{
hreg->offset = stacksize;
stacksize += size;
}
}
return stacksize;
}
static void layout_stack_frame(void)
{
int stacksize = 0;
stacksize = pack_stackframe(stacksize, 8, burm_bytes8_ATTR);
stacksize = pack_stackframe(stacksize, 4, burm_bytes4_ATTR);
stacksize = pack_stackframe(stacksize, 2, burm_bytes2_ATTR);
stacksize = pack_stackframe(stacksize, 1, burm_bytes1_ATTR);
current_proc->spills_size = stacksize;
}
void pass_register_allocator(struct procedure* proc)
{
current_proc = proc;
populate_hregs();
wire_up_blocks_ins_outs();
assign_hregs_to_vregs();
insert_phi_copies();
layout_stack_frame();
}
/* vim: set sw=4 ts=4 expandtab : */

View file

@ -1,17 +1,35 @@
#include "mcg.h"
/* mcg stack frames are laid out as:
*
* | ...params...
* | --------------- <- ap
* | saved regs
* | --------------- <- st
* | spills
* | --------------- <- fp (a.k.a. lb)
* | locals
* | --------------- <- sp
* V ...user area...
*
*/
void platform_calculate_offsets(struct procedure* proc)
{
proc->fp_to_st = proc->spills_size;
proc->fp_to_ap = proc->fp_to_st + proc->saved_size + 8;
proc->fp_to_lb = 0;
}
struct hop* platform_prologue(struct procedure* proc)
{
int framesize = proc->nlocals + 8;
int retbase = proc->nlocals;
struct hop* hop = new_hop(proc->entry, NULL);
hop_add_insel(hop, "addi sp, fp, %d", -framesize);
hop_add_insel(hop, "addi sp, sp, %d", proc->fp_to_ap + proc->locals_size);
hop_add_insel(hop, "mfspr 0, lr");
hop_add_insel(hop, "stw fp, %d(sp)", retbase);
hop_add_insel(hop, "stw 0, %d(sp)", retbase+4);
hop_add_insel(hop, "addi fp, sp, retbase");
hop_add_insel(hop, "stw fp, %d(sp)", proc->fp_to_st + proc->locals_size);
hop_add_insel(hop, "stw 0, %d(sp)", proc->fp_to_st + proc->locals_size + 4);
hop_add_insel(hop, "addi fp, sp, %d", proc->locals_size);
return hop;
}
@ -30,7 +48,14 @@ struct hop* platform_move(struct basicblock* bb, struct hreg* src, struct hreg*
struct hop* hop = new_hop(bb, NULL);
if ((src->type & burm_int_ATTR) && (dest->type & burm_int_ATTR))
hop_add_insel(hop, "mr %H, %H", dest, src);
{
if (src->is_stacked)
hop_add_insel(hop, "lwz %H, %S(fp) ! %H", dest, src, src);
else if (dest->is_stacked)
hop_add_insel(hop, "stw %H, %S(fp) ! %H", src, dest, dest);
else
hop_add_insel(hop, "mr %H, %H", dest, src);
}
else
fatal("cannot generate move from %s to %s", src->name, dest->name);

View file

@ -1,5 +1,7 @@
#include "mcg.h"
extern struct procedure* current_proc;
static void print_blocks(char k, struct procedure* proc)
{
int i;
@ -157,8 +159,6 @@ static void write_dominance_graph(const char* name)
void procedure_compile(struct procedure* proc)
{
int i;
pass_group_irs(proc);
print_blocks('1', proc);
@ -189,10 +189,11 @@ void procedure_compile(struct procedure* proc)
pass_find_phi_congruence_groups();
pass_live_vreg_analysis();
print_hops('8', proc);
pass_register_allocator();
pass_register_allocator(proc);
pass_add_prologue_epilogue(proc);
print_hops('9', proc);
platform_calculate_offsets(proc);
emit_procedure(proc);
if (cfg_dot_file)

View file

@ -13,7 +13,12 @@ struct procedure
const char* name;
struct basicblock* entry;
struct basicblock* exit;
size_t nlocals;
int locals_size;
int spills_size;
int saved_size;
int fp_to_st;
int fp_to_ap;
int fp_to_lb;
ARRAYOF(struct basicblock) blocks;
IMAPOF(struct local) locals;
};

View file

@ -20,15 +20,16 @@ struct hreg* new_hreg(const struct burm_register_data* brd)
return hreg;
}
struct hreg* new_stacked_hreg(int offset, uint32_t type)
struct hreg* new_stacked_hreg(uint32_t type)
{
static int hreg_count = 1;
struct hreg* hreg = calloc(1, sizeof *hreg);
hreg->name = aprintf("stacked_%d", offset);
hreg->name = aprintf("stacked_%d_id_%d", type, hreg_count++);
hreg->realname = hreg->name;
hreg->type = type;
hreg->attrs = type;
hreg->is_stacked = true;
hreg->offset = offset;
hreg->offset = -1;
return hreg;
}

View file

@ -8,7 +8,7 @@ struct phicongruence
int id;
ARRAYOF(struct vreg) vregs;
ARRAYOF(struct hop) definitions;
uint32_t attrs;
uint32_t type;
};
struct hreg
@ -24,6 +24,7 @@ struct hreg
struct vreg
{
int id;
uint32_t type;
struct phicongruence* congruence;
struct hop* defined;
ARRAYOF(struct hop) used;
@ -34,7 +35,7 @@ typedef PMAPOF(struct hreg, struct vreg) register_assignment_t;
extern struct vreg* new_vreg(void);
extern struct hreg* new_hreg(const struct burm_register_data* brd);
extern struct hreg* new_stacked_hreg(int offset, uint32_t type);
extern struct hreg* new_stacked_hreg(uint32_t type);
#endif

View file

@ -721,6 +721,7 @@ static void insn_ivalue(int opcode, arith value)
/* This is actually ignored --- the entire block gets special
* treatment. But a lot of the rest of the code assumes that
* all basic blocks have one instruction, so we insert one. */
array_append(&current_proc->exit->irs,
new_ir0(
IR_RET, 0