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1 /* Copyright JS Foundation and other contributors, http://js.foundation
2  *
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef VM_STACK_H
17 #define VM_STACK_H
18 
19 #include "ecma-globals.h"
20 
21 /** \addtogroup vm Virtual machine
22  * @{
23  *
24  * \addtogroup stack VM stack
25  * @{
26  */
27 
28 /**
29  * Create context on the vm stack.
30  */
31 #define VM_CREATE_CONTEXT(type, end_offset) ((ecma_value_t) ((type) | ((end_offset) << 7)))
32 
33 /**
34  * Create context on the vm stack with environment.
35  */
36 #define VM_CREATE_CONTEXT_WITH_ENV(type, end_offset) \
37   (VM_CREATE_CONTEXT ((type),(end_offset)) | VM_CONTEXT_HAS_LEX_ENV)
38 
39 /**
40  * Get type of a vm context.
41  */
42 #define VM_GET_CONTEXT_TYPE(value) ((vm_stack_context_type_t) ((value) & 0x1f))
43 
44 /**
45  * Get the end position of a vm context.
46  */
47 #define VM_GET_CONTEXT_END(value) ((value) >> 7)
48 
49 /**
50  * This flag is set if the context has a lexical environment.
51  */
52 #define VM_CONTEXT_HAS_LEX_ENV 0x20
53 
54 /**
55  * This flag is set if the iterator close operation should be invoked during a for-of context break.
56  */
57 #define VM_CONTEXT_CLOSE_ITERATOR 0x40
58 
59 /**
60  * Context types for the vm stack.
61  */
62 typedef enum
63 {
64   /* Update VM_CONTEXT_IS_FINALLY macro if the following three values are changed. */
65   VM_CONTEXT_FINALLY_JUMP,                    /**< finally context with a jump */
66   VM_CONTEXT_FINALLY_THROW,                   /**< finally context with a throw */
67   VM_CONTEXT_FINALLY_RETURN,                  /**< finally context with a return */
68   VM_CONTEXT_TRY,                             /**< try context */
69   VM_CONTEXT_CATCH,                           /**< catch context */
70 #if ENABLED (JERRY_ES2015)
71   VM_CONTEXT_BLOCK,                           /**< block context */
72 #endif /* ENABLED (JERRY_ES2015) */
73   VM_CONTEXT_WITH,                            /**< with context */
74   VM_CONTEXT_FOR_IN,                          /**< for-in context */
75 #if ENABLED (JERRY_ES2015)
76   VM_CONTEXT_FOR_OF,                          /**< for-of context */
77 #endif /* ENABLED (JERRY_ES2015) */
78 } vm_stack_context_type_t;
79 
80 /**
81  * Checks whether the context type is a finally type.
82  */
83 #define VM_CONTEXT_IS_FINALLY(context_type) \
84   ((context_type) <= VM_CONTEXT_FINALLY_RETURN)
85 
86 /**
87  * Shift needs to be applied to get the next item of the offset array.
88  */
89 #define VM_CONTEXT_OFFSET_SHIFT 4
90 
91 /**
92  * Checks whether an offset is available.
93  */
94 #define VM_CONTEXT_HAS_NEXT_OFFSET(offsets) ((offsets) >= (1 << VM_CONTEXT_OFFSET_SHIFT))
95 
96 /**
97  * Gets the next offset from the offset array.
98  */
99 #define VM_CONTEXT_GET_NEXT_OFFSET(offsets) (-((int32_t) ((offsets) & ((1 << VM_CONTEXT_OFFSET_SHIFT) - 1))))
100 
101 ecma_value_t *vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, ecma_value_t *vm_stack_top_p);
102 bool vm_stack_find_finally (vm_frame_ctx_t *frame_ctx_p, ecma_value_t **vm_stack_top_ref_p,
103                             vm_stack_context_type_t finally_type, uint32_t search_limit);
104 uint32_t vm_get_context_value_offsets (ecma_value_t *context_item_p);
105 void vm_ref_lex_env_chain (ecma_object_t *lex_env_p, uint16_t context_depth,
106                            ecma_value_t *context_end_p, bool do_ref);
107 
108 /**
109  * @}
110  * @}
111  */
112 
113 #endif /* !VM_STACK_H */
114