* Project: libFIRM
* File name: ir/opt/scalar_replace.c
* Purpose: scalar replacement of arrays and compounds
- * Author: Beyhan
+ * Author: Beyhan Veliev
+ * Modified by: Michael Beck
* Created:
* CVS-ID: $Id$
* Copyright: (c) 1998-2005 Universität Karlsruhe
* Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
*/
#ifdef HAVE_CONFIG_H
-# include "config.h"
+#include "config.h"
#endif
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
+
+#ifdef HAVE_MALLOC_H
+#include <malloc.h>
+#endif
+
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+
+#include "scalar_replace.h"
+#include "irflag_t.h"
+#include "irouts.h"
+#include "set.h"
+#include "pset.h"
+#include "array.h"
+#include "tv.h"
+#include "ircons_t.h"
+#include "hashptr.h"
+#include "irgwalk.h"
+#include "irgmod.h"
+#include "irnode_t.h"
+#include "irtools.h"
+
+#define SET_VNUM(node, vnum) set_irn_link(node, INT_TO_PTR(vnum))
+#define GET_VNUM(node) (unsigned)PTR_TO_INT(get_irn_link(node))
+
+/**
+ * A path element entry: it is either an entity
+ * or a tarval, because we evaluate only constant array
+ * accesses like a.b.c[8].d
+ */
+typedef union {
+ entity *ent;
+ tarval *tv;
+} path_elem_t;
+
+/**
+ * An access path, used to assign value numbers
+ * to variables that will be scalar replaced
+ */
+typedef struct _path_t {
+ unsigned vnum; /**< the value number */
+ unsigned path_len; /**< the length of the access path */
+ path_elem_t path[1]; /**< the path */
+} path_t;
+
+typedef struct _scalars_t {
+ entity *ent; /**< A entity for scalar replacement. */
+ type *ent_owner; /**< The owner of this entity. */
+} scalars_t;
+
+
+/**
+ * Compare two pathes.
+ *
+ * @return 0 if they are identically
+ */
+static int path_cmp(const void *elt, const void *key, size_t size)
+{
+ const path_t *p1 = elt;
+ const path_t *p2 = key;
+
+ /* we can use memcmp here, because identical tarvals should have identical addresses */
+ return memcmp(p1->path, p2->path, p1->path_len * sizeof(p1->path[0]));
+}
+
+/**
+ * Compare two elements of the scalars_t set.
+ *
+ * @return 0 if they are identically
+ */
+static int ent_cmp(const void *elt, const void *key, size_t size)
+{
+ const scalars_t *c1 = elt;
+ const scalars_t *c2 = key;
+
+ return c1->ent != c2->ent;
+}
+
+/**
+ * Calculate a hash value for a path.
+ */
+static unsigned path_hash(const path_t *path)
+{
+ unsigned hash = 0;
+ unsigned i;
+
+ for (i = 0; i < path->path_len; ++i)
+ hash ^= (unsigned)PTR_TO_INT(path->path[i].ent);
+
+ return hash >> 4;
+}
+
+/**
+ * Returns non-zero, if all indeces of a Sel node are constants.
+ *
+ * @param sel the Sel node that will be checked
+ */
+static int is_const_sel(ir_node *sel) {
+ int i, n = get_Sel_n_indexs(sel);
+
+ for (i = 0; i < n; ++i) {
+ ir_node *idx = get_Sel_index(sel, i);
+
+ if (get_irn_op(idx) != op_Const)
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * Returns non-zero, if the address of an entity
+ * represented by a Sel node (or it's successor Sels) is taken.
+ */
+int is_address_taken(ir_node *sel)
+{
+ int i, n;
+
+ if (! is_const_sel(sel))
+ return 1;
+
+ n = get_irn_n_outs(sel);
+ for (i = 0; i < n; ++i) {
+ ir_node *succ = get_irn_out(sel, i);
+
+ switch (get_irn_opcode(succ)) {
+ case iro_Load:
+ /* ok, we just load from that entity */
+ break;
+
+ case iro_Store:
+ /* check that Sel is not the Store's value */
+ if (get_Store_value(succ) == sel)
+ return 1;
+ break;
+
+ case iro_Sel: {
+ /* Check the Sel successor of Sel */
+ int res = is_address_taken(succ);
+
+ if (res)
+ return 1;
+ break;
+ }
+
+ case iro_Call:
+ /* The address of an entity is given as a parameter.
+ * As long as we do not have analyses that can tell what
+ * is done with parameters, think is taken.
+ */
+ return 1;
+
+ default:
+ /* another op, the address is taken */
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/**
+ * Link all leave Sels with the entity.
+ *
+ * @param ent the entity that will be scalar replaced
+ * @param sel a Sel node that selects some fields of this entity
+ */
+static void link_all_leave_sels(entity *ent, ir_node *sel)
+{
+ int i, n, flag = 1;
+
+ n = get_irn_n_outs(sel);
+ for (i = 0; i < n; ++i) {
+ ir_node *succ = get_irn_out(sel, i);
+
+ if (get_irn_op(succ) == op_Sel) {
+ link_all_leave_sels(ent, succ);
+ flag = 0;
+ }
+ }
+
+ if (flag) {
+ /* if Sel nodes with memory inputs are used, a entity can be
+ * visited more than once causing a ring here, so we use the
+ * node flag to mark linked nodes
+ */
+ if (irn_visited(sel))
+ return;
+
+ /* we know we are at a leave, because this function is only
+ * called if the address is NOT taken, so succ must be a Load
+ * or a Store node
+ */
+ set_irn_link(sel, get_entity_link(ent));
+ set_entity_link(ent, sel);
+
+ mark_irn_visited(sel);
+ }
+}
+
+/* we need a special address that serves as an address taken marker */
+static char _x;
+static void *ADDRESS_TAKEN = &_x;
+
+/**
+ * Find possible scalar replacements.
+ *
+ * @param irg an IR graph
+ *
+ * This function finds variables on the (members of the) frame type
+ * that can be scalar replaced, because their address is never taken.
+ * If such a variable is found, it's entity link will hold a list of all
+ * Sel nodes, that selects the atomic fields of this entity.
+ * Otherwise, the link will be ADDRESS_TAKEN or NULL.
+ *
+ * @return non-zero if at least one entity could be replaced
+ * potentially
+ */
+static int find_possible_replacements(ir_graph *irg)
+{
+ ir_node *irg_frame = get_irg_frame(irg);
+ int i, n;
+ int res = 0;
+
+ inc_irg_visited(irg);
+
+ n = get_irn_n_outs(irg_frame);
+
+ /*
+ * First, clear the link field of all interesting entities.
+ * Note that we did not rely on the fact that there is only
+ * one Sel node per entity, so we might access one entity
+ * more than once here.
+ * That's why we have need two loops.
+ */
+ for (i = 0; i < n; ++i) {
+ ir_node *succ = get_irn_out(irg_frame, i);
+
+ if (get_irn_op(succ) == op_Sel) {
+ entity *ent = get_Sel_entity(succ);
+ set_entity_link(ent, NULL);
+ }
+ }
+
+ /*
+ * Check the ir_graph for Sel nodes. If the entity of Sel
+ * isn't a scalar replacement set the link of this entity
+ * equal ADDRESS_TAKEN.
+ */
+ for (i = 0; i < n; ++i) {
+ ir_node *succ = get_irn_out(irg_frame, i);
+
+ if (get_irn_op(succ) == op_Sel) {
+ entity *ent = get_Sel_entity(succ);
+ type *ent_type;
+
+ if (get_entity_link(ent) == ADDRESS_TAKEN)
+ continue;
+
+ ent_type = get_entity_type(ent);
+
+ /* we can handle arrays, structs and atomic types yet */
+ if (is_Array_type(ent_type) || is_Struct_type(ent_type) || is_atomic_type(ent_type)) {
+ if (is_address_taken(succ)) {
+ if (get_entity_link(ent)) /* killing one */
+ --res;
+ set_entity_link(ent, ADDRESS_TAKEN);
+ }
+ else {
+ /* possible found one */
+ if (get_entity_link(ent) == NULL)
+ ++res;
+ link_all_leave_sels(ent, succ);
+ }
+ }
+ }
+ }
+
+ return res;
+}
+
+/**
+ * Return a path from the Sel node sel to it's root.
+ *
+ * @param sel the Sel node
+ * @param len the length of the path so far
+ */
+static path_t *find_path(ir_node *sel, unsigned len)
+{
+ int pos, i, n;
+ path_t *res;
+ ir_node *pred = get_Sel_ptr(sel);
+
+ /* the current Sel node will add some path elements */
+ n = get_Sel_n_indexs(sel);
+ len += n + 1;
+
+ if (get_irn_op(pred) != op_Sel) {
+ /* we found the root */
+
+ res = xmalloc(sizeof(*res) + (len - 1) * sizeof(res->path));
+ res->path_len = len;
+ }
+ else
+ res = find_path(pred, len);
+
+ pos = res->path_len - len;
+
+ res->path[pos++].ent = get_Sel_entity(sel);
+ for (i = 0; i < n; ++i) {
+ ir_node *index = get_Sel_index(sel, i);
+
+ res->path[pos++].tv = get_Const_tarval(index);
+ }
+ return res;
+}
+
+
+/**
+ * Allocate value numbers for the leaves
+ * in our found entities.
+ *
+ * @param sels a set that will contain all Sels that have a value number
+ * @param ent the entity that will be scalar replaced
+ * @param vnum the first value number we can assign
+ * @param modes a flexible array, containing all the modes of
+ * the value numbers.
+ *
+ * @return the next free value number
+ */
+static unsigned allocate_value_numbers(pset *sels, entity *ent, unsigned vnum, ir_mode ***modes)
+{
+ ir_node *sel, *next;
+ path_t *key, *path;
+ set *pathes = new_set(path_cmp, 8);
+
+ /* visit all Sel nodes in the chain of the entity */
+ for (sel = get_entity_link(ent); sel; sel = next) {
+ next = get_irn_link(sel);
+
+ /* we must mark this sel for later */
+ pset_insert_ptr(sels, sel);
+
+ key = find_path(sel, 0);
+ path = set_find(pathes, key, sizeof(*key) + sizeof(key->path[0]) * key->path_len, path_hash(key));
+
+ if (path)
+ SET_VNUM(sel, path->vnum);
+ else {
+ unsigned i;
+
+ key->vnum = vnum++;
+
+ set_insert(pathes, key, sizeof(*key) + sizeof(key->path[0]) * key->path_len, path_hash(key));
+
+ SET_VNUM(sel, key->vnum);
+ ARR_EXTO(ir_mode *, *modes, (key->vnum + 15) & ~15);
+
+ (*modes)[key->vnum] = get_type_mode(get_entity_type(get_Sel_entity(sel)));
+
+ assert((*modes)[key->vnum] && "Value is not atomic");
+
+#ifdef DEBUG_libfirm
+ /* Debug output */
+ if (get_opt_scalar_replacement_verbose() && get_firm_verbosity() > 1) {
+ printf(" %s", get_entity_name(ent));
+ for (i = 1; i < key->path_len; ++i) {
+ if (is_entity(key->path[i].ent))
+ printf(".%s", get_entity_name(key->path[i].ent));
+ else
+ printf("[%ld]", get_tarval_long(key->path[i].tv));
+ }
+ printf(" = %u (%s)\n", PTR_TO_INT(get_irn_link(sel)), get_mode_name((*modes)[key->vnum]));
+ }
+#endif /* DEBUG_libfirm */
+ }
+ free(key);
+ }
+
+ del_set(pathes);
+ set_entity_link(ent, NULL);
+ return vnum;
+}
+
+/**
+ * A list entry for the fixing lists
+ */
+typedef struct _list_entry_t {
+ ir_node *node; /**< the node that must be fixed */
+ unsigned vnum; /**< the value number of this node */
+} list_entry_t;
+
+/**
+ * environment for memory walker
+ */
+typedef struct _env_t {
+ struct obstack obst; /**< a obstack for the value blocks */
+ int nvals; /**< number of values */
+ ir_mode **modes; /**< the modes of the values */
+ list_entry_t *fix_phis; /**< list of all Phi nodes that must be fixed */
+ list_entry_t *fix_loads; /**< list of all Load nodes that must be fixed */
+ pset *sels; /**< A set of all Sel nodes that have a value number */
+} env_t;
+
+/**
+ * Walker
+ */
+static void handle_first(ir_node *node, void *ctx)
+{
+ env_t *env = ctx;
+ ir_op *op = get_irn_op(node);
+ ir_node *adr, *block, *mem, *unk, **value_arr, **in;
+ unsigned vnum;
+ int i, j, n;
+ list_entry_t *l;
+
+ if (op == op_Load) {
+ /* a load, check if we can resolve it */
+ adr = get_Load_ptr(node);
+
+ if (get_irn_op(adr) != op_Sel)
+ return;
+
+ if (! pset_find_ptr(env->sels, adr))
+ return;
+
+ /* ok, we have a Load that will be replaced */
+ vnum = GET_VNUM(adr);
+
+ assert(vnum < (unsigned)env->nvals);
+
+ block = get_nodes_block(node);
+ value_arr = get_irn_link(block);
+
+ /* check, if we can replace this Load */
+ if (value_arr[vnum]) {
+ mem = get_Load_mem(node);
+
+ turn_into_tuple(node, pn_Load_max);
+ set_Tuple_pred(node, pn_Load_M, mem);
+ set_Tuple_pred(node, pn_Load_res, value_arr[vnum]);
+ set_Tuple_pred(node, pn_Load_X_except, new_Bad());
+ }
+ else {
+ l = obstack_alloc(&env->obst, sizeof(*l));
+ l->node = node;
+ l->vnum = vnum;
+
+ set_irn_link(node, env->fix_loads);
+ env->fix_loads = l;
+ }
+ }
+ else if (op == op_Store) {
+ /* a Store always can be replaced */
+ adr = get_Store_ptr(node);
+
+ if (get_irn_op(adr) != op_Sel)
+ return;
+
+ if (! pset_find_ptr(env->sels, adr))
+ return;
+
+ vnum = GET_VNUM(adr);
+
+ assert(vnum < (unsigned)env->nvals);
+
+ block = get_nodes_block(node);
+ value_arr = get_irn_link(block);
+
+ value_arr[vnum] = get_Store_value(node);
+
+ mem = get_Store_mem(node);
+
+ turn_into_tuple(node, pn_Store_max);
+ set_Tuple_pred(node, pn_Store_M, mem);
+ set_Tuple_pred(node, pn_Store_X_except, new_Bad());
+ }
+ else if (op == op_Phi && get_irn_mode(node) == mode_M) {
+ /*
+ * found a memory Phi: Here, we must create new Phi nodes
+ */
+ block = get_nodes_block(node);
+ value_arr = get_irn_link(block);
+
+ n = get_Block_n_cfgpreds(block);
+
+ in = alloca(sizeof(*in) * n);
+
+ for (i = env->nvals - 1; i >= 0; --i) {
+ unk = new_Unknown(env->modes[i]);
+ for (j = n - 1; j >= 0; --j)
+ in[j] = unk;
+
+ value_arr[i] = new_r_Phi(current_ir_graph, block, n, in, env->modes[i]);
+
+ l = obstack_alloc(&env->obst, sizeof(*l));
+ l->node = value_arr[i];
+ l->vnum = i;
+
+ set_irn_link(value_arr[i], env->fix_phis);
+ env->fix_phis = l;
+ }
+ }
+}
+
+/**
+ * Walker: allocate the value array for every block.
+ */
+static void alloc_value_arr(ir_node *block, void *ctx)
+{
+ env_t *env = ctx;
+ ir_node **var_arr = obstack_alloc(&env->obst, sizeof(*var_arr) * env->nvals);
+
+ /* the value array is empty at start */
+ memset(var_arr, 0, sizeof(*var_arr) * env->nvals);
+ set_irn_link(block, var_arr);
+}
+
+/**
+ * searches through blocks beginning from block for value
+ * vnum and return it.
+ */
+static ir_node *find_value(ir_node *block, unsigned vnum)
+{
+ ir_node **value_arr;
+ int i;
+ ir_node *res;
+
+ if (Block_not_block_visited(block)) {
+ mark_Block_block_visited(block);
+
+ value_arr = get_irn_link(block);
+
+ if (value_arr[vnum])
+ return value_arr[vnum];
+
+ for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) {
+ ir_node *pred = get_Block_cfgpred(block, i);
+
+ res = find_value(get_nodes_block(pred), vnum);
+ if (res)
+ return res;
+ }
+ }
+ return NULL;
+}
+
+/**
+ * fix the Phi list
+ */
+static void fix_phis(env_t *env)
+{
+ list_entry_t *l;
+ ir_node *phi, *block, *pred, *val;
+ int i;
+
+ for (l = env->fix_phis; l; l = get_irn_link(phi)) {
+ phi = l->node;
+
+ block = get_nodes_block(phi);
+ for (i = get_irn_arity(phi) - 1; i >= 0; --i) {
+ pred = get_Block_cfgpred(block, i);
+ pred = get_nodes_block(pred);
+
+ inc_irg_block_visited(current_ir_graph);
+ val = find_value(pred, l->vnum);
+
+ if (val)
+ set_irn_n(phi, i, val);
+ }
+ }
+}
+
+/**
+ * fix the Load list
+ */
+static void fix_loads(env_t *env)
+{
+ list_entry_t *l;
+ ir_node *load, *block, *pred, *val, *mem;
+ int i;
+
+ for (l = env->fix_loads; l; l = get_irn_link(load)) {
+ load = l->node;
+
+ block = get_nodes_block(load);
+ for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) {
+ pred = get_Block_cfgpred(block, i);
+ pred = get_nodes_block(pred);
+
+ inc_irg_block_visited(current_ir_graph);
+ val = find_value(pred, l->vnum);
+
+ if (val)
+ break;
+ }
+
+ if (! val) {
+ /* access of an uninitialized value */
+ val = new_Unknown(env->modes[l->vnum]);
+ }
+
+ mem = get_Load_mem(load);
+
+ turn_into_tuple(load, pn_Load_max);
+ set_Tuple_pred(load, pn_Load_M, mem);
+ set_Tuple_pred(load, pn_Load_res, val);
+ set_Tuple_pred(load, pn_Load_X_except, new_Bad());
+ }
+}
+
+/**
+ * Make scalar replacement.
+ *
+ * @param sels A set containing all Sel nodes that have a value number
+ * @param nvals The number of scalars.
+ * @param modes A flexible array, containing all the modes of
+ * the value numbers.
+ */
+static void do_scalar_replacements(pset *sels, int nvals, ir_mode **modes)
+{
+ env_t env;
+
+ obstack_init(&env.obst);
+ env.nvals = nvals;
+ env.modes = modes;
+ env.fix_phis = NULL;
+ env.fix_loads = NULL;
+ env.sels = sels;
+
+ /* first step: allocate the value arrays for every block */
+ irg_block_walk_graph(current_ir_graph, NULL, alloc_value_arr, &env);
+
+ /*
+ * second step: walk over the graph blockwise in topological order
+ * and fill the array as much as possible.
+ */
+ irg_walk_blkwise_graph(current_ir_graph, NULL, handle_first, &env);
+
+ /* third, fix the list of Phis, then the list of Loads */
+ fix_phis(&env);
+ fix_loads(&env);
+
+ obstack_free(&env.obst, NULL);
+}
+
/*
- * find possible scalar replacements
+ * Find possible scalar replacements
+ *
+ * @param irg The current ir graph.
*/
-void find_scalar_replacements(irgraph *irg)
+void scalar_replacement_opt(ir_graph *irg)
{
+ unsigned nvals;
+ int i;
+ scalars_t key, *value;
+ ir_node *irg_frame;
+ ir_mode **modes;
+ set *set_ent;
+ pset *sels;
+ type *ent_type;
+ ir_graph *rem;
+
+ if (! get_opt_scalar_replacement())
+ return;
+
+ rem = current_ir_graph;
+
+ /* Call algorithm that computes the out edges */
+ if (get_irg_outs_state(irg) != outs_consistent)
+ compute_irg_outs(irg);
+
+ /* Find possible scalar replacements */
+ if (find_possible_replacements(irg)) {
+
+ if (get_opt_scalar_replacement_verbose()) {
+ printf("Scalar Replacement: %s\n", get_entity_name(get_irg_entity(irg)));
+ }
+
+ /* Insert in set the scalar replacements. */
+ irg_frame = get_irg_frame(irg);
+ nvals = 0;
+ modes = NEW_ARR_F(ir_mode *, 16);
+ set_ent = new_set(ent_cmp, 8);
+ sels = pset_new_ptr(8);
+
+ for (i = 0 ; i < get_irn_n_outs(irg_frame); i++) {
+ ir_node *succ = get_irn_out(irg_frame, i);
+
+ if (get_irn_op(succ) == op_Sel) {
+ entity *ent = get_Sel_entity(succ);
+
+ if (get_entity_link(ent) == NULL || get_entity_link(ent) == ADDRESS_TAKEN)
+ continue;
+
+ ent_type = get_entity_type(ent);
+
+ key.ent = ent;
+ key.ent_owner = get_entity_owner(ent);
+ set_insert(set_ent, &key, sizeof(key), HASH_PTR(key.ent));
+
+ if (get_opt_scalar_replacement_verbose()) {
+ if (is_Array_type(ent_type)) {
+ printf(" found array %s\n", get_entity_name(ent));
+ }
+ else if (is_Struct_type(ent_type)) {
+ printf(" found struct %s\n", get_entity_name(ent));
+ }
+ else if (is_atomic_type(ent_type))
+ printf(" found atomic value %s\n", get_entity_name(ent));
+ else {
+ assert(0 && "Neither an array nor a struct or atomic value");
+ }
+ }
+
+ nvals = allocate_value_numbers(sels, ent, nvals, &modes);
+ }
+ }
+
+ if (get_opt_scalar_replacement_verbose()) {
+ printf(" %u values will be needed\n", nvals);
+ }
+
+ /* If scalars were found. */
+ if (nvals) {
+ do_scalar_replacements(sels, nvals, modes);
+
+ for (value = set_first(set_ent); value; value = set_next(set_ent)) {
+ remove_class_member(value->ent_owner, value->ent);
+ }
+ }
+
+ del_pset(sels);
+ del_set(set_ent);
+ DEL_ARR_F(modes);
+
+ if (nvals) {
+ /*
+ * We changed the graph, but did NOT introduce new blocks
+ * neither changed control flow, cf-backedges should be still
+ * consistent.
+ */
+ set_irg_outs_inconsistent(irg);
+ set_irg_loopinfo_inconsistent(irg);
+ }
+ }
+
+ current_ir_graph = rem;
}
projects / libfirm / blobdiff