Commit f763fa15 authored by Matthias Braun's avatar Matthias Braun
Browse files

remove class cast optimization

parent eb38e825
......@@ -626,69 +626,6 @@ FIRM_API void opt_tail_recursion(void);
*/
FIRM_API ir_prog_pass_t *opt_tail_recursion_pass(const char *name);
/** This is the type for a method, that returns a pointer type to
* tp. This is needed in the normalization. */
typedef ir_type *(*gen_pointer_type_to_func)(ir_type *tp);
/** Insert Casts so that class type casts conform exactly with the type hierarchy.
*
* Formulated in Java, this achieves the following:
*
* For a class hierarchy
* class A {}
* class B extends A {}
* class C extends B {}
* we transforms a cast
* (A)new C()
* to
* (A)((B)new C()).
*
* The algorithm works for Casts with class types, but also for Casts
* with all pointer types that point (over several indirections,
* i.e. ***A) to a class type. Normalizes all graphs. Computes type
* information (@see irtypeinfo.h) if not available.
* Invalidates trout information as new casts are generated.
*
* @param gppt_fct A function that returns a pointer type that points
* to the type given as argument. If this parameter is NULL, a default
* function is used that either uses trout information or performs a O(n)
* search to find an existing pointer type. If it can not find a type,
* generates a pointer type with mode_P_mach and suffix "cc_ptr_tp".
*/
FIRM_API void normalize_irp_class_casts(gen_pointer_type_to_func gppt_fct);
/** Insert Casts so that class type casts conform exactly with the type hierarchy
* in given graph.
*
* For more details see normalize_irp_class_casts().
*
* This transformation requires that type information is computed. @see irtypeinfo.h.
*/
FIRM_API void normalize_irg_class_casts(ir_graph *irg,
gen_pointer_type_to_func gppt_fct);
/** Optimize casting between class types.
*
* class A { m(); }
* class B extends A { }
* class C extends B {}
* Performs the following transformations:
* C c = (C)(B)(A)(B)new C() --> C c = (C)(B)newC() --> C c = new C()
* (Optimizing downcasts as A a = (A)(B)(new A()) --> A a = new A() can
* be suppressed by setting the flag opt_suppress_downcast_optimization.
* Downcasting A to B might cause an exception. It is not clear
* whether this is modeled by the Firm Cast node, as it has no exception
* outputs.);
* If there is inh_m() that overwrites m() in B:
* ((A) new B()).m() --> (new B()).inh_m()
* Phi((A)x, (A)y) --> (A) Phi (x, y) if (A) is an upcast.
*
* Computes type information if not available. @see irtypeinfo.h.
* Typeinformation is valid after optimization.
* Invalidates trout information.
*/
FIRM_API void optimize_class_casts(void);
/**
* CLiff Click's combo algorithm from
* "Combining Analyses, combining Optimizations".
......
......@@ -104,8 +104,6 @@ void ir_init(void)
/* Builds a construct allowing to access all information to be constructed
later. */
init_irprog_2();
/* class cast optimization */
firm_init_class_casts_opt();
/* memory disambiguation */
firm_init_memory_disambiguator();
firm_init_loop_opt();
......
......@@ -140,7 +140,6 @@ ir_graph *new_r_ir_graph(ir_entity *ent, int n_loc)
res->typeinfo_state = ir_typeinfo_none;
set_irp_typeinfo_inconsistent(); /* there is a new graph with typeinfo_none. */
res->callee_info_state = irg_callee_info_none;
res->class_cast_state = ir_class_casts_transitive;
res->fp_model = fp_model_precise;
res->mem_disambig_opt = aa_opt_inherited;
......
......@@ -99,7 +99,6 @@ static void complete_ir_prog(ir_prog *irp, const char *module_name)
set_class_final(irp->segment_types[IR_SEGMENT_GLOBAL], 1);
irp->const_code_irg = new_const_code_irg();
irp->class_cast_state = ir_class_casts_transitive;
irp->globals_entity_usage_state = ir_entity_usage_not_computed;
#undef IDENT
}
......
......@@ -514,7 +514,6 @@ struct ir_graph {
op_pin_state irg_pinned_state; /**< Flag for status of nodes. */
ir_typeinfo_state typeinfo_state; /**< Validity of type information. */
irg_callee_info_state callee_info_state; /**< Validity of callee information. */
ir_class_cast_state class_cast_state; /**< Kind of cast operations in code. */
unsigned mem_disambig_opt; /**< Options for the memory disambiguator. */
unsigned fp_model; /**< floating point model of the graph. */
......@@ -623,7 +622,6 @@ struct ir_prog {
size_t max_callgraph_recursion_depth; /**< needed in callgraph. */
double max_method_execution_frequency; /**< needed in callgraph. */
loop_nesting_depth_state lnd_state; /**< The state of loop nesting depth information. */
ir_class_cast_state class_cast_state; /**< The state of cast operations in code. */
ir_entity_usage_computed_state globals_entity_usage_state;
ir_label_t last_label_nr; /**< The highest label number for generating unique labels. */
......
......@@ -33,8 +33,6 @@ void firm_init_reassociation(void);
void firm_init_scalar_replace(void);
void firm_init_class_casts_opt(void);
void firm_init_loop_opt(void);
#endif
/*
* Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
*
* This file is part of libFirm.
*
* This file may be distributed and/or modified under the terms of the
* GNU General Public License version 2 as published by the Free Software
* Foundation and appearing in the file LICENSE.GPL included in the
* packaging of this file.
*
* Licensees holding valid libFirm Professional Edition licenses may use
* this file in accordance with the libFirm Commercial License.
* Agreement provided with the Software.
*
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE.
*/
/**
* @file
* @brief Perform optimizations of the type representation.
* @date 20.4.2005
* @author Goetz Lindenmaier
*/
#include "config.h"
#include <assert.h>
#include "iroptimize.h"
#include "irprog.h"
#include "irtypeinfo.h"
#include "irgwalk.h"
#include "trouts.h"
#include "ircons.h"
#include "irgmod.h"
#include "irflag_t.h"
#include "xmalloc.h"
#include "debug.h"
#include "opt_init.h"
DEBUG_ONLY(static firm_dbg_module_t *dbg;)
/* - statistics ---------------------------------------------- */
static size_t n_casts_normalized = 0;
static size_t n_casts_removed = 0;
static size_t n_sels_concretized = 0;
/* - Cast normalization. ------------------------------------- */
static ir_type *default_gen_pointer_type_to(ir_type *tp);
#define PTR_TYPE_SUFFIX "cc_ptr_tp" /* class cast pointer type. */
static ident *ptr_type_suffix = NULL;
static gen_pointer_type_to_func gen_pointer_type_to = default_gen_pointer_type_to;
/**
* Find a pointer type to a given type.
* Uses and updates trouts if available.
*/
static ir_type *default_gen_pointer_type_to(ir_type *tp)
{
ir_type *res = find_pointer_type_to_type(tp);
if (is_unknown_type(res))
res = new_type_pointer(tp);
return res;
}
/** Return a type that is a depth times pointer to type. */
static ir_type *pointerize_type(ir_type *tp, size_t depth)
{
for (; depth > 0; --depth) {
tp = gen_pointer_type_to(tp);
}
return tp;
}
static ir_node *normalize_values_type(ir_type *totype, ir_node *pred)
{
ir_type *fromtype = get_irn_typeinfo_type(pred);
ir_node *new_cast = pred;
ir_node *block;
size_t ref_depth = 0;
if (totype == fromtype) return pred; /* Case for optimization! */
while (is_Pointer_type(totype) && is_Pointer_type(fromtype)) {
totype = get_pointer_points_to_type(totype);
fromtype = get_pointer_points_to_type(fromtype);
++ref_depth;
}
if (!is_Class_type(totype)) return pred;
if (!is_Class_type(fromtype)) return pred;
if ((get_class_supertype_index(totype, fromtype) != (size_t)-1) ||
(get_class_supertype_index(fromtype, totype) != (size_t)-1) ) {
/* It's just what we want ... */
return pred;
}
block = get_nodes_block(pred);
if (is_SubClass_of(totype, fromtype)) {
/* downcast */
while (get_class_subtype_index(fromtype, totype) == (size_t)-1) {
/* Insert a cast to a subtype of fromtype. */
ir_type *new_type = NULL;
ir_node *new_cast;
size_t i;
size_t n_subtypes = get_class_n_subtypes(fromtype);
for (i = 0; i < n_subtypes && !new_type; ++i) {
ir_type *new_sub = get_class_subtype(fromtype, i);
if (is_SuperClass_of(new_sub, totype))
new_type = new_sub;
}
assert(new_type);
fromtype = new_type;
new_type = pointerize_type(new_type, ref_depth);
new_cast = new_r_Cast(block, pred, new_type);
pred = new_cast;
++n_casts_normalized;
set_irn_typeinfo_type(new_cast, new_type); /* keep type information up to date. */
}
} else {
assert(is_SuperClass_of(totype, fromtype));
/* upcast */
while (get_class_supertype_index(fromtype, totype) == (size_t)-1) {
/* Insert a cast to a supertype of fromtype. */
ir_type *new_type = NULL;
size_t i, n_supertypes = get_class_n_supertypes(fromtype);
for (i = 0; i < n_supertypes && !new_type; ++i) {
ir_type *new_super = get_class_supertype(fromtype, i);
if (is_SubClass_of(new_super, totype))
new_type = new_super;
}
assert(new_type);
fromtype = new_type;
new_type = pointerize_type(new_type, ref_depth);
new_cast = new_r_Cast(block, pred, new_type);
pred = new_cast;
++n_casts_normalized;
set_irn_typeinfo_type(new_cast, new_type); /* keep type information up to date. */
}
}
return new_cast;
}
/**
* Post-Walker.
*/
static void normalize_irn_class_cast(ir_node *n, void *env)
{
ir_node *res;
(void) env;
if (is_Cast(n)) {
ir_node *pred = get_Cast_op(n);
ir_type *totype = get_Cast_type(n);
res = normalize_values_type(totype, pred);
set_Cast_op(n, res);
} else if (is_Call(n)) {
size_t n_params = get_Call_n_params(n);
size_t i;
ir_type *tp = get_Call_type(n);
for (i = 0; i < n_params; ++i) {
res = normalize_values_type(get_method_param_type(tp, i), get_Call_param(n, i));
set_Call_param(n, i, res);
}
}
}
static void pure_normalize_irg_class_casts(ir_graph *irg)
{
assert(get_irg_class_cast_state(irg) != ir_class_casts_any &&
"Cannot normalize irregular casts.");
if (get_irg_class_cast_state(irg) == ir_class_casts_normalized) {
return;
}
irg_walk_graph(irg, NULL, normalize_irn_class_cast, NULL);
set_irg_class_cast_state(irg, ir_class_casts_normalized);
}
void normalize_irg_class_casts(ir_graph *irg, gen_pointer_type_to_func gppt_fct)
{
assert(get_irp_typeinfo_state() == ir_typeinfo_consistent);
if (gppt_fct) gen_pointer_type_to = gppt_fct;
if (!ptr_type_suffix)
ptr_type_suffix = new_id_from_str(PTR_TYPE_SUFFIX);
pure_normalize_irg_class_casts(irg);
gen_pointer_type_to = default_gen_pointer_type_to;
}
void normalize_irp_class_casts(gen_pointer_type_to_func gppt_fct)
{
size_t i, n;
if (gppt_fct) gen_pointer_type_to = gppt_fct;
for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
ir_graph *irg = get_irp_irg(i);
pure_normalize_irg_class_casts(irg);
}
set_irp_class_cast_state(ir_class_casts_normalized);
gen_pointer_type_to = default_gen_pointer_type_to;
DB((dbg, SET_LEVEL_1, " Cast normalization: %zu Casts inserted.\n", n_casts_normalized));
}
/* - Cast optimization. ------------------------------------------- */
/**
* Optimizes Casts:
*
* (T1)(T2)x<T1> -> x<T1>
*
* (T3)(T2)x<T1> -> (T3)x<T1>
*
* if possible.
*
* @param cast the Cast node
*
* @return 1 if the cast was changed
*/
static int cancel_out_casts(ir_node *cast)
{
ir_node *orig, *pred = get_Cast_op(cast);
ir_type *tp_cast, *tp_pred, *tp_orig;
if (!is_Cast(pred)) return 0;
orig = get_Cast_op(pred);
tp_cast = get_Cast_type(cast);
tp_pred = get_Cast_type(pred);
tp_orig = get_irn_typeinfo_type(orig);
while (is_Pointer_type(tp_cast) &&
is_Pointer_type(tp_pred) &&
is_Pointer_type(tp_orig) ) {
tp_cast = get_pointer_points_to_type(tp_cast);
tp_pred = get_pointer_points_to_type(tp_pred);
tp_orig = get_pointer_points_to_type(tp_orig);
}
if (!is_Class_type(tp_cast) || !is_Class_type(tp_pred) || !is_Class_type(tp_orig))
return 0;
if (is_SubClass_of(tp_pred, tp_cast) && get_opt_suppress_downcast_optimization())
return 0;
if (tp_cast == tp_orig) {
exchange(cast, orig);
n_casts_removed += 2;
return 1;
}
if (!(is_SubClass_of (tp_cast, tp_orig) || is_SubClass_of (tp_orig, tp_cast))) {
/* Avoid (B2)(A)(new B1()) --> (B2)(new B1())
* if B1 =!> B2 and B2 =!> B1
*/
return 0;
}
if ((is_SubClass_of (tp_cast, tp_pred) && is_SuperClass_of(tp_pred, tp_orig)) ||
(is_SuperClass_of(tp_cast, tp_pred) && is_SubClass_of (tp_pred, tp_orig))) {
/* Cast --> Pred --> Orig */
set_Cast_op(cast, orig);
++n_casts_removed;
return 1;
}
return 0;
}
/**
* Optimize Sel(Cast(type, ptr), ent) into Sel(ptr_type, ent_type)
*
* @param sel the Sel node
*
* @return 1 if Cast's where removed
*/
static int concretize_selected_entity(ir_node *sel)
{
int res = 0;
ir_entity *sel_ent = get_Sel_entity(sel);
ir_node *cast = get_Sel_ptr(sel);
while (is_Cast(cast)) {
ir_type *cast_tp = get_Cast_type(cast);
ir_node *ptr = get_Cast_op(cast);
ir_type *orig_tp = get_irn_typeinfo_type(ptr);
/* we handle only classes */
if (!is_Pointer_type(orig_tp)|| !is_Pointer_type(cast_tp))
return res;
orig_tp = get_pointer_points_to_type(orig_tp);
cast_tp = get_pointer_points_to_type(cast_tp);
if (!is_Class_type(orig_tp) || !is_Class_type(cast_tp))
return res;
/* We only want to concretize, but not generalize. */
if (!is_SuperClass_of(cast_tp, orig_tp))
return res;
/* The sel entity should be a member of the cast_tp, else
the graph was not properly typed. */
if (get_class_member_index(cast_tp, sel_ent) == (size_t)-1)
return res;
ir_entity *new_ent = resolve_ent_polymorphy(orig_tp, sel_ent);
/* New ent must be member of orig_tp. */
if (get_class_member_index(orig_tp, new_ent) == (size_t)-1)
return res;
/* all checks done, we can remove the Cast and update the Sel */
set_Sel_entity(sel, new_ent);
set_Sel_ptr(sel, ptr);
++n_sels_concretized;
sel_ent = new_ent;
cast = ptr;
res = 1;
}
return res;
}
/**
* Move Casts of the same type through a Phi node, i.e.
* Phi(Cast(type, x_0), ..., Cast(type, x_n)) -> Cast(type, Phi(x_0, ..., x_n))
*
* @param phi the Phi node
*
* @return 1 if Cast's where moved
*/
static int concretize_Phi_type(ir_node *phi)
{
int n_preds = get_Phi_n_preds(phi);
ir_node **pred = ALLOCAN(ir_node*, n_preds);
ir_node *nn, *blk;
ir_type *totype;
ir_type *fromtype;
int i;
if (n_preds == 0)
return 0;
pred[0] = get_Phi_pred(phi, 0);
if (!is_Cast(pred[0]))
return 0;
if (!is_Cast_upcast(pred[0]))
return 0;
fromtype = get_irn_typeinfo_type(get_Cast_op(pred[0]));
totype = get_Cast_type(pred[0]);
pred[0] = get_Cast_op(pred[0]);
for (i = 1; i < n_preds; ++i) {
pred[i] = get_Phi_pred(phi, i);
if (!is_Cast(pred[i]))
return 0;
if (get_irn_typeinfo_type(get_Cast_op(pred[i])) != fromtype)
return 0;
pred[i] = get_Cast_op(pred[i]);
}
/* Transform Phi */
blk = get_nodes_block(phi);
nn = new_r_Phi(blk, n_preds, pred, get_irn_mode(phi));
set_irn_typeinfo_type(nn, fromtype);
nn = new_r_Cast(blk, nn, totype);
set_irn_typeinfo_type(nn, totype);
exchange(phi, nn);
return 1;
}
/**
* Remove Casted null checks, i.e.
*
* Cmp(Cast(type, x_orig), NULL_type) -> Cmp(x_orig, NULL_orig)
*
* @param cmp the Cmp node
*
* @return 1 if Cast's where removed
*/
static int remove_Cmp_Null_cast(ir_node *cmp)
{
ir_graph *irg;
ir_node *cast, *null, *new_null;
int cast_pos, null_pos;
ir_type *fromtype;
ir_mode *mode;
cast = get_Cmp_left(cmp);
if (!is_Cast(cast)) {
null = cast;
null_pos = 0;
cast = get_Cmp_right(cmp);
cast_pos = 1;
if (!is_Cast(cast))
return 0;
} else {
null = get_Cmp_right(cmp);
cast_pos = 0;
null_pos = 1;
}
if (! is_Const(null))
return 0;
mode = get_irn_mode(null);
if (!mode_is_reference(mode))
return 0;
if (get_Const_tarval(null) != get_mode_null(mode))
return 0;
/* Transform Cmp */
irg = get_irn_irg(cmp);
set_irn_n(cmp, cast_pos, get_Cast_op(cast));
fromtype = get_irn_typeinfo_type(get_Cast_op(cast));
new_null = new_r_Const(irg, get_Const_tarval(null));
set_irn_typeinfo_type(new_null, fromtype);
set_irn_n(cmp, null_pos, new_null);
++n_casts_removed;
return 1;
}
/**
* Post-Walker: Optimize class casts (mostly by trying to remove them)
*/
static void irn_optimize_class_cast(ir_node *n, void *env)
{
int *changed = (int*)env;
if (is_Cast(n))
*changed |= cancel_out_casts(n);
else if (is_Sel(n))
*changed |= concretize_selected_entity(n);
else if (is_Phi(n))
*changed |= concretize_Phi_type(n);
else if (is_Cmp(n))
*changed |= remove_Cmp_Null_cast(n);
}
void optimize_class_casts(void)
{
int changed;
changed = 0;
all_irg_walk(NULL, irn_optimize_class_cast, &changed);
DB((dbg, SET_LEVEL_1, " Cast optimization: %zu Casts removed, %zu Sels concretized.\n",
n_casts_removed, n_sels_concretized));
}
void firm_init_class_casts_opt(void)
{
FIRM_DBG_REGISTER(dbg, "firm.opt.tropt");
}
......@@ -571,38 +571,3 @@ ir_entity *resolve_ent_polymorphy(ir_type *dynamic_class, ir_entity *static_ent)
return res;
}
/* ----------------------------------------------------------------------- */
/* Class cast state handling. */
/* ----------------------------------------------------------------------- */
/* - State handling. ----------------------------------------- */
void set_irg_class_cast_state(ir_graph *irg, ir_class_cast_state s)
{
if (get_irp_class_cast_state() > s)
set_irp_class_cast_state(s);
irg->class_cast_state = s;
}
ir_class_cast_state get_irg_class_cast_state(const ir_graph *irg)
{
return irg->class_cast_state;
}
void set_irp_class_cast_state(ir_class_cast_state s)
{
#ifndef NDEBUG
size_t i, n;
for (i = 0, n = get_irp_n_irgs(); i < n; ++i)
assert(get_irg_class_cast_state(get_irp_irg(i)) >= s);
#endif
irp->class_cast_state = s;
}