1 /*
2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "opto/addnode.hpp"
27 #include "opto/castnode.hpp"
28 #include "opto/connode.hpp"
29 #include "opto/matcher.hpp"
30 #include "opto/phaseX.hpp"
31 #include "opto/subnode.hpp"
32 #include "opto/type.hpp"
33
34 //=============================================================================
35 // If input is already higher or equal to cast type, then this is an identity.
36 Node *ConstraintCastNode::Identity( PhaseTransform *phase ) {
37 return phase->type(in(1))->higher_equal_speculative(_type) ? in(1) : this;
38 }
39
40 //------------------------------Value------------------------------------------
41 // Take 'join' of input and cast-up type
42 const Type *ConstraintCastNode::Value( PhaseTransform *phase ) const {
43 if( in(0) && phase->type(in(0)) == Type::TOP ) return Type::TOP;
44 const Type* ft = phase->type(in(1))->filter_speculative(_type);
45
46 #ifdef ASSERT
47 // Previous versions of this function had some special case logic,
48 // which is no longer necessary. Make sure of the required effects.
49 switch (Opcode()) {
50 case Op_CastII:
51 {
52 const Type* t1 = phase->type(in(1));
53 if( t1 == Type::TOP ) assert(ft == Type::TOP, "special case #1");
54 const Type* rt = t1->join_speculative(_type);
55 if (rt->empty()) assert(ft == Type::TOP, "special case #2");
56 break;
57 }
58 case Op_CastPP:
59 if (phase->type(in(1)) == TypePtr::NULL_PTR &&
60 _type->isa_ptr() && _type->is_ptr()->_ptr == TypePtr::NotNull)
61 assert(ft == Type::TOP, "special case #3");
62 break;
63 }
64 #endif //ASSERT
65
66 return ft;
67 }
68
69 //------------------------------Ideal------------------------------------------
70 // Return a node which is more "ideal" than the current node. Strip out
71 // control copies
72 Node *ConstraintCastNode::Ideal(PhaseGVN *phase, bool can_reshape){
73 return (in(0) && remove_dead_region(phase, can_reshape)) ? this : NULL;
74 }
75
76 //------------------------------Ideal_DU_postCCP-------------------------------
77 // Throw away cast after constant propagation
78 Node *ConstraintCastNode::Ideal_DU_postCCP( PhaseCCP *ccp ) {
79 const Type *t = ccp->type(in(1));
80 ccp->hash_delete(this);
81 set_type(t); // Turn into ID function
82 ccp->hash_insert(this);
83 return this;
84 }
85
86
87 //=============================================================================
88
89 //------------------------------Ideal_DU_postCCP-------------------------------
90 // If not converting int->oop, throw away cast after constant propagation
91 Node *CastPPNode::Ideal_DU_postCCP( PhaseCCP *ccp ) {
92 const Type *t = ccp->type(in(1));
93 if (!t->isa_oop_ptr() || ((in(1)->is_DecodeN()) && Matcher::gen_narrow_oop_implicit_null_checks())) {
94 return NULL; // do not transform raw pointers or narrow oops
95 }
96 return ConstraintCastNode::Ideal_DU_postCCP(ccp);
97 }
98
99
100
101 //=============================================================================
102 //------------------------------Identity---------------------------------------
103 // If input is already higher or equal to cast type, then this is an identity.
104 Node *CheckCastPPNode::Identity( PhaseTransform *phase ) {
105 // Toned down to rescue meeting at a Phi 3 different oops all implementing
106 // the same interface. CompileTheWorld starting at 502, kd12rc1.zip.
107 return (phase->type(in(1)) == phase->type(this)) ? in(1) : this;
108 }
109
110 //------------------------------Value------------------------------------------
111 // Take 'join' of input and cast-up type, unless working with an Interface
112 const Type *CheckCastPPNode::Value( PhaseTransform *phase ) const {
113 if( in(0) && phase->type(in(0)) == Type::TOP ) return Type::TOP;
114
115 const Type *inn = phase->type(in(1));
116 if( inn == Type::TOP ) return Type::TOP; // No information yet
117
118 const TypePtr *in_type = inn->isa_ptr();
119 const TypePtr *my_type = _type->isa_ptr();
120 const Type *result = _type;
121 if( in_type != NULL && my_type != NULL ) {
122 TypePtr::PTR in_ptr = in_type->ptr();
123 if( in_ptr == TypePtr::Null ) {
124 result = in_type;
125 } else if( in_ptr == TypePtr::Constant ) {
126 // Casting a constant oop to an interface?
127 // (i.e., a String to a Comparable?)
128 // Then return the interface.
129 const TypeOopPtr *jptr = my_type->isa_oopptr();
130 assert( jptr, "" );
131 result = (jptr->klass()->is_interface() || !in_type->higher_equal(_type))
132 ? my_type->cast_to_ptr_type( TypePtr::NotNull )
133 : in_type;
134 } else {
135 result = my_type->cast_to_ptr_type( my_type->join_ptr(in_ptr) );
136 }
137 }
138
139 // This is the code from TypePtr::xmeet() that prevents us from
140 // having 2 ways to represent the same type. We have to replicate it
141 // here because we don't go through meet/join.
142 if (result->remove_speculative() == result->speculative()) {
143 result = result->remove_speculative();
144 }
145
146 // Same as above: because we don't go through meet/join, remove the
147 // speculative type if we know we won't use it.
148 return result->cleanup_speculative();
149
150 // JOIN NOT DONE HERE BECAUSE OF INTERFACE ISSUES.
151 // FIX THIS (DO THE JOIN) WHEN UNION TYPES APPEAR!
152
153 //
154 // Remove this code after overnight run indicates no performance
155 // loss from not performing JOIN at CheckCastPPNode
156 //
157 // const TypeInstPtr *in_oop = in->isa_instptr();
158 // const TypeInstPtr *my_oop = _type->isa_instptr();
159 // // If either input is an 'interface', return destination type
160 // assert (in_oop == NULL || in_oop->klass() != NULL, "");
161 // assert (my_oop == NULL || my_oop->klass() != NULL, "");
162 // if( (in_oop && in_oop->klass()->is_interface())
163 // ||(my_oop && my_oop->klass()->is_interface()) ) {
164 // TypePtr::PTR in_ptr = in->isa_ptr() ? in->is_ptr()->_ptr : TypePtr::BotPTR;
165 // // Preserve cast away nullness for interfaces
166 // if( in_ptr == TypePtr::NotNull && my_oop && my_oop->_ptr == TypePtr::BotPTR ) {
167 // return my_oop->cast_to_ptr_type(TypePtr::NotNull);
168 // }
169 // return _type;
170 // }
171 //
172 // // Neither the input nor the destination type is an interface,
173 //
174 // // history: JOIN used to cause weird corner case bugs
175 // // return (in == TypeOopPtr::NULL_PTR) ? in : _type;
176 // // JOIN picks up NotNull in common instance-of/check-cast idioms, both oops.
177 // // JOIN does not preserve NotNull in other cases, e.g. RawPtr vs InstPtr
178 // const Type *join = in->join(_type);
179 // // Check if join preserved NotNull'ness for pointers
180 // if( join->isa_ptr() && _type->isa_ptr() ) {
181 // TypePtr::PTR join_ptr = join->is_ptr()->_ptr;
182 // TypePtr::PTR type_ptr = _type->is_ptr()->_ptr;
183 // // If there isn't any NotNull'ness to preserve
184 // // OR if join preserved NotNull'ness then return it
185 // if( type_ptr == TypePtr::BotPTR || type_ptr == TypePtr::Null ||
186 // join_ptr == TypePtr::NotNull || join_ptr == TypePtr::Constant ) {
187 // return join;
188 // }
189 // // ELSE return same old type as before
190 // return _type;
191 // }
192 // // Not joining two pointers
193 // return join;
194 }
195
196 //------------------------------Ideal------------------------------------------
197 // Return a node which is more "ideal" than the current node. Strip out
198 // control copies
199 Node *CheckCastPPNode::Ideal(PhaseGVN *phase, bool can_reshape){
200 return (in(0) && remove_dead_region(phase, can_reshape)) ? this : NULL;
201 }
202
203 //=============================================================================
204 //------------------------------Value------------------------------------------
205 const Type *CastX2PNode::Value( PhaseTransform *phase ) const {
206 const Type* t = phase->type(in(1));
207 if (t == Type::TOP) return Type::TOP;
208 if (t->base() == Type_X && t->singleton()) {
209 uintptr_t bits = (uintptr_t) t->is_intptr_t()->get_con();
210 if (bits == 0) return TypePtr::NULL_PTR;
211 return TypeRawPtr::make((address) bits);
212 }
213 return CastX2PNode::bottom_type();
214 }
215
216 //------------------------------Idealize---------------------------------------
217 static inline bool fits_in_int(const Type* t, bool but_not_min_int = false) {
218 if (t == Type::TOP) return false;
219 const TypeX* tl = t->is_intptr_t();
220 jint lo = min_jint;
221 jint hi = max_jint;
222 if (but_not_min_int) ++lo; // caller wants to negate the value w/o overflow
223 return (tl->_lo >= lo) && (tl->_hi <= hi);
224 }
225
226 static inline Node* addP_of_X2P(PhaseGVN *phase,
227 Node* base,
228 Node* dispX,
229 bool negate = false) {
230 if (negate) {
231 dispX = new SubXNode(phase->MakeConX(0), phase->transform(dispX));
232 }
233 return new AddPNode(phase->C->top(),
234 phase->transform(new CastX2PNode(base)),
235 phase->transform(dispX));
236 }
237
238 Node *CastX2PNode::Ideal(PhaseGVN *phase, bool can_reshape) {
239 // convert CastX2P(AddX(x, y)) to AddP(CastX2P(x), y) if y fits in an int
240 int op = in(1)->Opcode();
241 Node* x;
242 Node* y;
243 switch (op) {
244 case Op_SubX:
245 x = in(1)->in(1);
246 // Avoid ideal transformations ping-pong between this and AddP for raw pointers.
247 if (phase->find_intptr_t_con(x, -1) == 0)
248 break;
249 y = in(1)->in(2);
250 if (fits_in_int(phase->type(y), true)) {
251 return addP_of_X2P(phase, x, y, true);
252 }
253 break;
254 case Op_AddX:
255 x = in(1)->in(1);
256 y = in(1)->in(2);
257 if (fits_in_int(phase->type(y))) {
258 return addP_of_X2P(phase, x, y);
259 }
260 if (fits_in_int(phase->type(x))) {
261 return addP_of_X2P(phase, y, x);
262 }
263 break;
264 }
265 return NULL;
266 }
267
268 //------------------------------Identity---------------------------------------
269 Node *CastX2PNode::Identity( PhaseTransform *phase ) {
270 if (in(1)->Opcode() == Op_CastP2X) return in(1)->in(1);
271 return this;
272 }
273
274 //=============================================================================
275 //------------------------------Value------------------------------------------
276 const Type *CastP2XNode::Value( PhaseTransform *phase ) const {
277 const Type* t = phase->type(in(1));
278 if (t == Type::TOP) return Type::TOP;
279 if (t->base() == Type::RawPtr && t->singleton()) {
280 uintptr_t bits = (uintptr_t) t->is_rawptr()->get_con();
281 return TypeX::make(bits);
282 }
283 return CastP2XNode::bottom_type();
284 }
285
286 Node *CastP2XNode::Ideal(PhaseGVN *phase, bool can_reshape) {
287 return (in(0) && remove_dead_region(phase, can_reshape)) ? this : NULL;
288 }
289
290 //------------------------------Identity---------------------------------------
291 Node *CastP2XNode::Identity( PhaseTransform *phase ) {
292 if (in(1)->Opcode() == Op_CastX2P) return in(1)->in(1);
293 return this;
294 }