Skip to content
GitLab
Commit 8bc1ae15 authored by Matthias Braun's avatar Matthias Braun
Browse files

benewalloc: cleanups; dump intermediate results; rework copy tracking logic;... 

benewalloc: cleanups; dump intermediate results; rework copy tracking logic; started working on SSA construction

[r26334]
parent 10978e64
Show whitespace changes
Inline Side-by-side
ir/be/benewalloc.c
View file @ 8bc1ae15
......@@ -40,9 +40,6 @@
*
* TODO:
* - make use of free registers in the permutate_values code
* - output constraints are not ensured. The algorithm fails to copy values
* away, so the registers for constrained outputs are free.
* - must_be_different constraint is not respected
* - We have to pessimistically construct Phi_0s when not all predecessors
* of a block are known.
* - Phi color assignment should give bonus points towards registers already
......@@ -54,6 +51,7 @@
#include "config.h"
#include <float.h>
#include <stdbool.h>
#include "obst.h"
#include "irnode_t.h"
......@@ -62,6 +60,7 @@
#include "ircons.h"
#include "irgwalk.h"
#include "execfreq.h"
#include "error.h"
#include "be.h"
#include "bera.h"
......@@ -89,6 +88,7 @@ static struct obstack obst;
static be_irg_t *birg;
static ir_graph *irg;
static const arch_register_class_t *cls;
static const arch_register_req_t *default_cls_req;
static be_lv_t *lv;
static const ir_exec_freq *execfreqs;
static unsigned n_regs;
......@@ -109,7 +109,8 @@ static assignment_t *assignments;
*/
struct allocation_info_t {
unsigned last_uses; /**< bitset indicating last uses (input pos) */
assignment_t *current_assignment;
ir_node *current_value; /**< copy of the value that should be used */
ir_node *original_value; /**< for copies point to original value */
float prefs[0]; /**< register preferences */
};
typedef struct allocation_info_t allocation_info_t;
......@@ -123,7 +124,7 @@ typedef struct reg_pref_t reg_pref_t;
/** per basic-block information */
struct block_info_t {
int processed; /**< indicate wether block is processed */
bool processed; /**< indicate wether block is processed */
assignment_t assignments[0]; /**< register assignments at end of block */
};
typedef struct block_info_t block_info_t;
......@@ -139,6 +140,8 @@ static allocation_info_t *get_allocation_info(ir_node *node)
size_t size = sizeof(info[0]) + n_regs * sizeof(info->prefs[0]);
info = obstack_alloc(&obst, size);
memset(info, 0, size);
info->current_value = node;
info->original_value = node;
set_irn_link(node, info);
} else {
info = get_irn_link(node);
......@@ -167,6 +170,24 @@ static block_info_t *get_block_info(ir_node *block)
return info;
}
/**
* Get default register requirement for the current register class
*/
static const arch_register_req_t *get_default_req_current_cls(void)
{
if (default_cls_req == NULL) {
struct obstack *obst = get_irg_obstack(irg);
arch_register_req_t *req = obstack_alloc(obst, sizeof(*req));
memset(req, 0, sizeof(*req));
req->type = arch_register_req_type_normal;
req->cls = cls;
default_cls_req = req;
}
return default_cls_req;
}
/**
* Link the allocation info of a node to a copy.
* Afterwards, both nodes uses the same allocation info.
......@@ -175,12 +196,18 @@ static block_info_t *get_block_info(ir_node *block)
* @param copy the node that gets the allocation info assigned
* @param value the original node
*/
static void link_to(ir_node *copy, ir_node *value)
static void mark_as_copy_of(ir_node *copy, ir_node *value)
{
allocation_info_t *info = get_allocation_info(value);
assert(!irn_visited(copy));
set_irn_link(copy, info);
mark_irn_visited(copy);
allocation_info_t *copy_info = get_allocation_info(copy);
/* value must be an original value (not a copy) */
assert(info->original_value == value);
info->current_value = copy;
/* the copy should not be linked to something else yet */
assert(copy_info->original_value == copy);
copy_info->original_value = value;
}
/**
......@@ -307,21 +334,25 @@ static void analyze_block(ir_node *block, void *data)
sched_foreach_reverse(block, node) {
allocation_info_t *info;
int i, arity;
int i;
int arity;
if (is_Phi(node)) {
/* TODO: handle constrained phi-nodes */
if (is_Phi(node))
break;
}
/* TODO give/take penalties for should_be_same/different) */
check_defs(&live_nodes, weight, node);
/* mark last uses */
arity = get_irn_arity(node);
/* I was lazy, and only allocated 1 unsigned
=> maximum of 32 uses per node (rewrite if necessary) */
assert(arity <= (int) sizeof(unsigned) * 8);
/* the allocation info node currently only uses 1 unsigned value
to mark last used inputs. So we will fail for a node with more than
32 inputs. */
if (arity >= (int) sizeof(unsigned) * 8) {
panic("Node with more than %d inputs not supported yet",
(int) sizeof(unsigned) * 8);
}
info = get_allocation_info(node);
for (i = 0; i < arity; ++i) {
......@@ -371,14 +402,10 @@ static void use_reg(ir_node *node, const arch_register_t *reg)
{
unsigned r = arch_register_get_index(reg);
assignment_t *assignment = &assignments[r];
allocation_info_t *info;
assert(assignment->value == NULL);
assignment->value = node;
info = get_allocation_info(node);
info->current_assignment = assignment;
arch_set_irn_register(node, reg);
}
......@@ -463,9 +490,6 @@ static void assign_reg(const ir_node *block, ir_node *node)
}
}
/* TODO: handle must_be_different */
/* */
DB((dbg, LEVEL_2, "Candidates for %+F:", node));
reg_prefs = alloca(n_regs * sizeof(reg_prefs[0]));
fill_sort_candidates(reg_prefs, info);
......@@ -478,10 +502,11 @@ static void assign_reg(const ir_node *block, ir_node *node)
for (i = 0; i < n_regs; ++i) {
unsigned r = reg_prefs[i].num;
/* ignores should be last and we should have a non-ignore left */
/* ignores are last and we should have at least 1 non-ignore left */
assert(!bitset_is_set(ignore_regs, r));
/* already used?
TODO: It might be better to copy the value occupying the register around here, find out when... */
TODO: It might be better to copy the value occupying the register
around here instead of trying the next one, find out when... */
if (assignments[r].value != NULL)
continue;
reg = arch_register_for_index(cls, r);
......@@ -493,42 +518,17 @@ static void assign_reg(const ir_node *block, ir_node *node)
static void free_reg_of_value(ir_node *node)
{
allocation_info_t *info;
assignment_t *assignment;
const arch_register_t *reg;
unsigned r;
if (!arch_irn_consider_in_reg_alloc(cls, node))
return;
info = get_allocation_info(node);
assignment = info->current_assignment;
assert(assignment != NULL);
r = assignment - assignments;
DB((dbg, LEVEL_2, "Value %+F ended, freeing %s\n",
node, arch_register_for_index(cls, r)->name));
reg = arch_get_irn_register(node);
r = arch_register_get_index(reg);
assignment = &assignments[r];
assignment->value = NULL;
info->current_assignment = NULL;
}
/**
* Return the index of the currently assigned register of a node.
*/
static unsigned get_current_reg(ir_node *node)
{
allocation_info_t *info = get_allocation_info(node);
assignment_t *assignment = info->current_assignment;
return assignment - assignments;
}
/**
* Return the currently assigned assignment of a node.
*/
static assignment_t *get_current_assignment(ir_node *node)
{
allocation_info_t *info = get_allocation_info(node);
return info->current_assignment;
}
/**
......@@ -621,11 +621,16 @@ static void permutate_values(ir_nodeset_t *live_nodes, ir_node *before,
/* create a copy */
src = ins[old_r];
copy = be_new_Copy(cls, block, src);
sched_add_before(before, copy);
reg = arch_register_for_index(cls, r);
DB((dbg, LEVEL_2, "Copy %+F (from %+F) -> %s\n", copy, src, reg->name));
link_to(copy, src);
DB((dbg, LEVEL_2, "Copy %+F (from %+F, before %+F) -> %s\n",
copy, src, before, reg->name));
mark_as_copy_of(copy, src);
use_reg(copy, reg);
sched_add_before(before, copy);
if (live_nodes != NULL) {
ir_nodeset_insert(live_nodes, copy);
}
/* old register has 1 user less, permutation is resolved */
assert(arch_register_get_index(arch_get_irn_register(src)) == old_r);
......@@ -673,11 +678,17 @@ static void permutate_values(ir_nodeset_t *live_nodes, ir_node *before,
in[0] = ins[r2];
in[1] = ins[old_r];
perm = be_new_Perm(cls, block, 2, in);
sched_add_before(before, perm);
DB((dbg, LEVEL_2, "Perm %+F (perm %+F,%+F, before %+F)\n",
perm, in[0], in[1], before));
proj0 = new_r_Proj(block, perm, get_irn_mode(in[0]), 0);
link_to(proj0, in[0]);
mark_as_copy_of(proj0, in[0]);
reg = arch_register_for_index(cls, old_r);
use_reg(proj0, reg);
if (live_nodes != NULL) {
ir_nodeset_insert(live_nodes, proj0);
}
proj1 = new_r_Proj(block, perm, get_irn_mode(in[1]), 1);
......@@ -689,8 +700,11 @@ static void permutate_values(ir_nodeset_t *live_nodes, ir_node *before,
reg = arch_register_for_index(cls, r2);
if (r == r2) {
/* if we have reached a fixpoint update data structures */
link_to(proj1, in[1]);
mark_as_copy_of(proj1, in[1]);
use_reg(proj1, reg);
if (live_nodes != NULL) {
ir_nodeset_insert(live_nodes, proj1);
}
} else {
arch_set_irn_register(proj1, reg);
}
......@@ -713,13 +727,14 @@ static void permutate_values(ir_nodeset_t *live_nodes, ir_node *before,
static void free_last_uses(ir_nodeset_t *live_nodes, ir_node *node)
{
allocation_info_t *info = get_allocation_info(node);
const unsigned *last_uses = &info->last_uses;
int arity = get_irn_arity(node);
int i;
for (i = 0; i < arity; ++i) {
ir_node *op;
/* check if one operand is the last use */
if (!rbitset_is_set(&info->last_uses, i))
if (!rbitset_is_set(last_uses, i))
continue;
op = get_irn_n(node, i);
......@@ -774,13 +789,14 @@ static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node)
int arity = get_irn_arity(node);
int i, dummy, res;
hungarian_problem_t *bp;
unsigned l, r, p;
unsigned l, r;
unsigned *assignment;
/* see if any use constraints are not met */
bool good = true;
for (i = 0; i < arity; ++i) {
ir_node *op = get_irn_n(node, i);
const arch_register_t *reg;
const arch_register_req_t *req;
const unsigned *limited;
unsigned r;
......@@ -794,7 +810,8 @@ static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node)
continue;
limited = req->limited;
r = get_current_reg(op);
reg = arch_get_irn_register(op);
r = arch_register_get_index(reg);
if (!rbitset_is_set(limited, r)) {
/* found an assignement outside the limited set */
good = false;
......@@ -853,8 +870,10 @@ static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node)
if (good)
return;
if (output_regs == NULL) {
if (live_through_regs == NULL) {
rbitset_alloca(live_through_regs, n_regs);
}
rbitset_alloca(output_regs, n_regs);
}
......@@ -882,6 +901,7 @@ static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node)
for (i = 0; i < arity; ++i) {
ir_node *op = get_irn_n(node, i);
const arch_register_t *reg;
const arch_register_req_t *req;
const unsigned *limited;
unsigned current_reg;
......@@ -894,7 +914,8 @@ static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node)
continue;
limited = req->limited;
current_reg = get_current_reg(op);
reg = arch_get_irn_register(op);
current_reg = arch_register_get_index(reg);
for (r = 0; r < n_regs; ++r) {
if (rbitset_is_set(limited, r))
continue;
......@@ -902,18 +923,20 @@ static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node)
}
}
hungarian_print_costmatrix(bp, 1);
//hungarian_print_costmatrix(bp, 1);
hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
assignment = ALLOCAN(unsigned, n_regs);
res = hungarian_solve(bp, (int*) assignment, &dummy, 0);
assert(res == 0);
#if 0
printf("Swap result:");
for (p = 0; p < n_regs; ++p) {
printf(" %d", assignment[p]);
for (i = 0; i < n_regs; ++i) {
printf(" %d", assignment[i]);
}
printf("\n");
#endif
hungarian_free(bp);
......@@ -921,19 +944,19 @@ static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node)
}
/** test wether a node @p n is a copy of the value of node @p of */
static int is_copy_of(ir_node *n, ir_node *of)
static bool is_copy_of(ir_node *n, ir_node *of)
{
allocation_info_t *of_info;
if (n == NULL)
return 0;
return false;
if (n == of)
return 1;
return true;
of_info = get_allocation_info(of);
if (!irn_visited(n))
return 0;
return false;
return of_info == get_irn_link(n);
}
......@@ -964,7 +987,7 @@ static void add_phi_permutations(ir_node *block, int p)
unsigned r;
unsigned *permutation;
assignment_t *old_assignments;
int need_permutation;
bool need_permutation;
ir_node *node;
ir_node *pred = get_Block_cfgpred_block(block, p);
......@@ -980,7 +1003,7 @@ static void add_phi_permutations(ir_node *block, int p)
}
/* check phi nodes */
need_permutation = 0;
need_permutation = false;
node = sched_first(block);
for ( ; is_Phi(node); node = sched_next(node)) {
const arch_register_t *reg;
......@@ -999,16 +1022,21 @@ static void add_phi_permutations(ir_node *block, int p)
regn = arch_register_get_index(reg);
if (regn != a) {
permutation[regn] = a;
need_permutation = 1;
need_permutation = true;
}
}
if (!need_permutation)
return;
/* permutate values at end of predecessor */
old_assignments = assignments;
assignments = pred_info->assignments;
permutate_values(NULL, be_get_end_of_block_insertion_point(pred),
permutation);
assignments = old_assignments;
/* change phi nodes to use the copied values */
node = sched_first(block);
for ( ; is_Phi(node); node = sched_next(node)) {
int a;
......@@ -1018,9 +1046,7 @@ static void add_phi_permutations(ir_node *block, int p)
continue;
op = get_Phi_pred(node, p);
/* TODO: optimize */
a = find_value_in_block_info(pred_info, op);
assert(a >= 0);
a = arch_register_get_index(arch_get_irn_register(node));
op = pred_info->assignments[a].value;
set_Phi_pred(node, p, op);
......@@ -1040,7 +1066,9 @@ static void allocate_coalesce_block(ir_node *block, void *data)
ir_node *node, *start;
int n_preds;
block_info_t *block_info;
block_info_t *processed_pred_info;
block_info_t **pred_block_infos;
bool all_preds_processed;
(void) data;
DB((dbg, LEVEL_2, "Allocating in block %+F\n", block));
......@@ -1049,26 +1077,28 @@ static void allocate_coalesce_block(ir_node *block, void *data)
block_info = get_block_info(block);
assignments = block_info->assignments;
for (r = 0; r < n_regs; ++r) {
assignment_t *assignment = &assignments[r];
ir_node *value = assignment->value;
allocation_info_t *info;
if (value == NULL)
continue;
info = get_allocation_info(value);
info->current_assignment = assignment;
}
ir_nodeset_init(&live_nodes);
/* gather regalloc infos of predecessor blocks */
n_preds = get_Block_n_cfgpreds(block);
pred_block_infos = ALLOCAN(block_info_t*, n_preds);
all_preds_processed = true;
for (i = 0; i < n_preds; ++i) {
ir_node *pred = get_Block_cfgpred_block(block, i);
pred_block_infos[i] = get_block_info(pred);
block_info_t *pred_info = get_block_info(pred);
pred_block_infos[i] = pred_info;
if (!pred_info->processed) {
all_preds_processed = false;
} else {
/* we need 1 (arbitrary) processed predecessor */
processed_pred_info = pred_info;
}
}
/* we create Phi0s (=SSA construction) if not all preds are known */
if (!all_preds_processed) {
block->attr.block.is_matured = 0;
}
/* collect live-in nodes and preassigned values */
......@@ -1079,9 +1109,6 @@ static void allocate_coalesce_block(ir_node *block, void *data)
if (!arch_irn_consider_in_reg_alloc(cls, node))
continue;
/* remember that this node is live at the beginning of the block */
ir_nodeset_insert(&live_nodes, node);
/* if the node already has a register assigned use it */
reg = arch_get_irn_register(node);
if (reg != NULL) {
......@@ -1092,6 +1119,30 @@ static void allocate_coalesce_block(ir_node *block, void *data)
where the predecessor allocation is not determined yet. */
use_reg(node, reg);
}
/* if we don't know all predecessors, then we have no idea which values
are copied, so we have to pessimistically construct phi-nodes for all
of them */
if (!all_preds_processed) {
ir_mode *mode = get_irn_mode(node);
ir_node *phi = new_r_Phi(block, 0, NULL, mode);
const arch_register_req_t *req = get_default_req_current_cls();
be_set_phi_reg_req(phi, req);
/* TODO: if node had a register assigned use that as a strong
preference */
mark_as_copy_of(phi, node);
sched_add_after(block, phi);
node = phi;
} else {
/* check wether the value is the same in all predecessors,
if not construct a phi node */
}
/* remember that this node is live at the beginning of the block */
ir_nodeset_insert(&live_nodes, node);
}
/* handle phis... */
......@@ -1142,14 +1193,14 @@ static void allocate_coalesce_block(ir_node *block, void *data)
/* exchange values to copied values where needed */
for (i = 0; i < arity; ++i) {
ir_node *op = get_irn_n(node, i);
assignment_t *assignment;
allocation_info_t *info;
if (!arch_irn_consider_in_reg_alloc(cls, op))
continue;
assignment = get_current_assignment(op);
assert(assignment != NULL);
if (op != assignment->value) {
set_irn_n(node, i, assignment->value);
info = get_allocation_info(op);
if (info->current_value != op) {
set_irn_n(node, i, info->current_value);
}
}
......@@ -1174,7 +1225,7 @@ static void allocate_coalesce_block(ir_node *block, void *data)
ir_nodeset_destroy(&live_nodes);
assignments = NULL;
block_info->processed = 1;
block_info->processed = true;
/* if we have exactly 1 successor then we might be able to produce phi
copies now */
......@@ -1213,6 +1264,13 @@ static void be_straight_alloc_cls(void)
ir_free_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_IRN_VISITED);
}
static void dump(int mask, ir_graph *irg, const char *suffix,
void (*dumper)(ir_graph *, const char *))
{
if(birg->main_env->options->dump_flags & mask)
be_dump(irg, suffix, dumper);
}
/**
* Run the spiller on the current graph.
*/
......@@ -1223,6 +1281,8 @@ static void spill(void)
be_pre_spill_prepare_constr(birg, cls);
BE_TIMER_POP(t_ra_constr);
dump(DUMP_RA, irg, "-spillprepare", dump_ir_block_graph_sched);
/* spill */
BE_TIMER_PUSH(t_ra_spill);
be_do_spill(birg, cls);
......@@ -1231,6 +1291,8 @@ static void spill(void)
BE_TIMER_PUSH(t_ra_spill_apply);
check_for_memory_operands(irg);
BE_TIMER_POP(t_ra_spill_apply);
dump(DUMP_RA, irg, "-spill", dump_ir_block_graph_sched);
}
/**
......@@ -1253,6 +1315,7 @@ static void be_straight_alloc(be_irg_t *new_birg)
for (c = 0; c < n_cls; ++c) {
cls = arch_env_get_reg_class(arch_env, c);
default_cls_req = NULL;
if (arch_register_class_flags(cls) & arch_register_class_flag_manual_ra)
continue;
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment

Imprint