1 /*
2 * Copyright (c) 2018, 2025, 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 #ifndef SHARE_VM_RUNTIME_CONTINUATION_HPP
26 #define SHARE_VM_RUNTIME_CONTINUATION_HPP
27
28 #include "jni.h"
29 #include "memory/allStatic.hpp"
30 #include "oops/oopsHierarchy.hpp"
31
32 class ContinuationEntry;
33 class frame;
34 class FrameValues;
35 class Handle;
36 class outputStream;
37 class RegisterMap;
38
39 class Continuations : public AllStatic {
40 public:
41 static void init();
42 static bool enabled();
43 };
44
45 void continuations_init();
46
47 class javaVFrame;
48 class JavaThread;
49
50 // should match Continuation.pinnedReason() in Continuation.java
51 enum freeze_result {
52 freeze_ok = 0,
53 freeze_ok_bottom = 1,
54 freeze_pinned_cs = 2,
55 freeze_pinned_native = 3,
56 freeze_exception = 4,
57 freeze_not_mounted = 5,
58 freeze_unsupported = 6
59 };
60
61 class Continuation : AllStatic {
62 public:
63
64 enum preempt_kind {
65 freeze_on_monitorenter,
66 freeze_on_wait
67 };
68
69 enum thaw_kind {
70 thaw_top = 0,
71 thaw_return_barrier = 1,
72 thaw_return_barrier_exception = 2,
73 };
74
75 static bool is_thaw_return_barrier(thaw_kind kind) {
76 return kind != thaw_top;
77 }
78
79 static bool is_thaw_return_barrier_exception(thaw_kind kind) {
80 bool r = (kind == thaw_return_barrier_exception);
81 assert(!r || is_thaw_return_barrier(kind), "must be");
82 return r;
83 }
84
85 static void init();
86
87 static address freeze_entry();
88 static address freeze_preempt_entry();
89 static int prepare_thaw(JavaThread* thread, bool return_barrier);
90 static address thaw_entry();
91
92 static freeze_result try_preempt(JavaThread* target, oop continuation);
93
94 static ContinuationEntry* get_continuation_entry_for_continuation(JavaThread* thread, oop continuation);
95 static ContinuationEntry* get_continuation_entry_for_sp(JavaThread* thread, intptr_t* const sp);
96 static ContinuationEntry* get_continuation_entry_for_entry_frame(JavaThread* thread, const frame& f);
97
98 static bool is_continuation_mounted(JavaThread* thread, oop continuation);
99
100 static bool is_cont_barrier_frame(const frame& f);
101 static bool is_return_barrier_entry(const address pc);
102 static bool is_continuation_enterSpecial(const frame& f);
103 static bool is_continuation_entry_frame(const frame& f, const RegisterMap *map);
104
105 static bool is_frame_in_continuation(const ContinuationEntry* entry, const frame& f);
106 static bool is_frame_in_continuation(JavaThread* thread, const frame& f);
107
108 static bool has_last_Java_frame(oop continuation, frame* frame, RegisterMap* map);
109 static frame last_frame(oop continuation, RegisterMap *map);
110 static frame top_frame(const frame& callee, RegisterMap* map);
111 static javaVFrame* last_java_vframe(Handle continuation, RegisterMap *map);
112 static frame continuation_parent_frame(RegisterMap* map);
113
114 static oop continuation_scope(oop continuation);
115 static bool is_scope_bottom(oop cont_scope, const frame& fr, const RegisterMap* map);
116
117 static bool is_in_usable_stack(address addr, const RegisterMap* map);
118
119 // pins/unpins the innermost mounted continuation; returns true on success or false if there's no continuation or the operation failed
120 static bool pin(JavaThread* current);
121 static bool unpin(JavaThread* current);
122
123 static frame continuation_bottom_sender(JavaThread* thread, const frame& callee, intptr_t* sender_sp);
124 static address get_top_return_pc_post_barrier(JavaThread* thread, address pc);
125 static void set_cont_fastpath_thread_state(JavaThread* thread);
126 static void notify_deopt(JavaThread* thread, intptr_t* sp);
127
128 // access frame data
129
130 #ifndef PRODUCT
131 static void describe(FrameValues &values);
132 #endif
133
134 private:
135 friend class InstanceStackChunkKlass;
136
137 #ifdef ASSERT
138 public:
139 static void debug_verify_continuation(oop continuation);
140 static void print(oop continuation);
141 static void print_on(outputStream* st, oop continuation);
142 #endif
143 };
144
145 void CONT_RegisterNativeMethods(JNIEnv *env, jclass cls);
146
147 #endif // SHARE_VM_RUNTIME_CONTINUATION_HPP