pebble/third_party/jerryscript/jerry-core/vm/vm-stack.c
2025-01-27 11:38:16 -08:00

256 lines
7.4 KiB
C

/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
* Copyright 2015-2016 University of Szeged.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "ecma-alloc.h"
#include "ecma-gc.h"
#include "ecma-helpers.h"
#include "vm-defines.h"
#include "vm-stack.h"
/** \addtogroup vm Virtual machine
* @{
*
* \addtogroup stack VM stack
* @{
*/
/**
* Abort (finalize) the current stack context, and remove it.
*
* @return new stack top
*/
ecma_value_t *
vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
ecma_value_t *vm_stack_top_p) /**< current stack top */
{
switch (VM_GET_CONTEXT_TYPE (vm_stack_top_p[-1]))
{
case VM_CONTEXT_FINALLY_THROW:
case VM_CONTEXT_FINALLY_RETURN:
{
ecma_free_value (vm_stack_top_p[-2]);
VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
vm_stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
break;
}
case VM_CONTEXT_FINALLY_JUMP:
case VM_CONTEXT_TRY:
{
VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
vm_stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
break;
}
case VM_CONTEXT_CATCH:
case VM_CONTEXT_WITH:
{
ecma_deref_object (frame_ctx_p->lex_env_p);
frame_ctx_p->lex_env_p = ecma_get_object_from_value (vm_stack_top_p[-2]);
JERRY_ASSERT (PARSER_TRY_CONTEXT_STACK_ALLOCATION == PARSER_WITH_CONTEXT_STACK_ALLOCATION);
VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
vm_stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
break;
}
case VM_CONTEXT_FOR_IN:
{
jmem_cpointer_t current = (jmem_cpointer_t) vm_stack_top_p[-2];
while (current != JMEM_CP_NULL)
{
ecma_collection_chunk_t *chunk_p = JMEM_CP_GET_NON_NULL_POINTER (ecma_collection_chunk_t,
current);
lit_utf8_byte_t *data_ptr = chunk_p->data;
ecma_free_value (*(ecma_value_t *) data_ptr);
current = chunk_p->next_chunk_cp;
ecma_dealloc_collection_chunk (chunk_p);
}
ecma_free_value (vm_stack_top_p[-3]);
VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FOR_IN_CONTEXT_STACK_ALLOCATION);
vm_stack_top_p -= PARSER_FOR_IN_CONTEXT_STACK_ALLOCATION;
break;
}
default:
{
JERRY_UNREACHABLE ();
break;
}
}
return vm_stack_top_p;
} /* vm_stack_context_abort */
/**
* Decode branch offset.
*
* @return branch offset
*/
static uint32_t
vm_decode_branch_offset (uint8_t *branch_offset_p, /**< start offset of byte code */
uint32_t length) /**< length of the branch */
{
uint32_t branch_offset = *branch_offset_p;
JERRY_ASSERT (length >= 1 && length <= 3);
switch (length)
{
case 3:
{
branch_offset <<= 8;
branch_offset |= *(branch_offset_p++);
/* FALLTHRU */
}
case 2:
{
branch_offset <<= 8;
branch_offset |= *(branch_offset_p++);
break;
}
}
return branch_offset;
} /* vm_decode_branch_offset */
/**
* Find a finally up to the end position.
*
* @return true if 'finally' found,
* false otherwise
*/
bool
vm_stack_find_finally (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
ecma_value_t **vm_stack_top_ref_p, /**< current stack top */
vm_stack_context_type_t finally_type, /**< searching this finally */
uint32_t search_limit) /**< search up-to this byte code */
{
ecma_value_t *vm_stack_top_p = *vm_stack_top_ref_p;
JERRY_ASSERT (finally_type <= VM_CONTEXT_FINALLY_RETURN);
if (finally_type != VM_CONTEXT_FINALLY_JUMP)
{
search_limit = 0xffffffffu;
}
while (frame_ctx_p->context_depth > 0)
{
vm_stack_context_type_t context_type;
uint32_t context_end = VM_GET_CONTEXT_END (vm_stack_top_p[-1]);
if (search_limit < context_end)
{
*vm_stack_top_ref_p = vm_stack_top_p;
return false;
}
context_type = VM_GET_CONTEXT_TYPE (vm_stack_top_p[-1]);
if (context_type == VM_CONTEXT_TRY || context_type == VM_CONTEXT_CATCH)
{
uint8_t *byte_code_p;
uint32_t branch_offset_length;
uint32_t branch_offset;
if (search_limit == context_end)
{
*vm_stack_top_ref_p = vm_stack_top_p;
return false;
}
byte_code_p = frame_ctx_p->byte_code_start_p + VM_GET_CONTEXT_END (vm_stack_top_p[-1]);
if (context_type == VM_CONTEXT_TRY)
{
JERRY_ASSERT (byte_code_p[0] == CBC_EXT_OPCODE);
if (byte_code_p[1] >= CBC_EXT_CATCH
&& byte_code_p[1] <= CBC_EXT_CATCH_3)
{
branch_offset_length = CBC_BRANCH_OFFSET_LENGTH (byte_code_p[1]);
branch_offset = vm_decode_branch_offset (byte_code_p + 2,
branch_offset_length);
if (finally_type == VM_CONTEXT_FINALLY_THROW)
{
branch_offset += (uint32_t) (byte_code_p - frame_ctx_p->byte_code_start_p);
vm_stack_top_p[-1] = VM_CREATE_CONTEXT (VM_CONTEXT_CATCH, branch_offset);
byte_code_p += 2 + branch_offset_length;
frame_ctx_p->byte_code_p = byte_code_p;
*vm_stack_top_ref_p = vm_stack_top_p;
return true;
}
byte_code_p += branch_offset;
if (*byte_code_p == CBC_CONTEXT_END)
{
VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
vm_stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
continue;
}
}
}
else
{
ecma_deref_object (frame_ctx_p->lex_env_p);
frame_ctx_p->lex_env_p = ecma_get_object_from_value (vm_stack_top_p[-2]);
if (byte_code_p[0] == CBC_CONTEXT_END)
{
VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
vm_stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
continue;
}
}
JERRY_ASSERT (byte_code_p[0] == CBC_EXT_OPCODE);
JERRY_ASSERT (byte_code_p[1] >= CBC_EXT_FINALLY
&& byte_code_p[1] <= CBC_EXT_FINALLY_3);
branch_offset_length = CBC_BRANCH_OFFSET_LENGTH (byte_code_p[1]);
branch_offset = vm_decode_branch_offset (byte_code_p + 2,
branch_offset_length);
branch_offset += (uint32_t) (byte_code_p - frame_ctx_p->byte_code_start_p);
vm_stack_top_p[-1] = VM_CREATE_CONTEXT ((uint32_t) finally_type, branch_offset);
byte_code_p += 2 + branch_offset_length;
frame_ctx_p->byte_code_p = byte_code_p;
*vm_stack_top_ref_p = vm_stack_top_p;
return true;
}
vm_stack_top_p = vm_stack_context_abort (frame_ctx_p, vm_stack_top_p);
}
*vm_stack_top_ref_p = vm_stack_top_p;
return false;
} /* vm_stack_find_finally */
/**
* @}
* @}
*/