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Remove the dlen to optimize it. (#4193)

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There are two reasons for this optimization:
- The value of dlen can equal 0x1_0000_0000, even in wasm32 mode, because it is derived from (4G-0). This results in a truncation when it is passed to b_memmove_s(). Consequently, s1max becomes 0 and n is greater than s1max. To correct this, a longer type is required.
- The dlen is only used to check if there is enough space in b_memmove_s(). However, from a different angle, after confirming that both src+len and dst+len are within the memory range, we can be assured and there is no need for this explicit check.
This commit is contained in:
liang.he 2025-04-17 15:21:02 +08:00 committed by GitHub
parent fc1527eacd
commit 996758cd4a
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GPG Key ID: B5690EEEBB952194
2 changed files with 33 additions and 29 deletions
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31
core/iwasm/interpreter/wasm_interp_classic.c
View File

@ -5784,7 +5784,6 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
{
mem_offset_t dst, src, len;
uint8 *mdst, *msrc;
uint64 dlen;
len = POP_MEM_OFFSET();
src = POP_MEM_OFFSET();
@ -5797,24 +5796,17 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
/* skip dst memidx */
frame_ip += 1;
#endif
// TODO: apply memidx
#if WASM_ENABLE_THREAD_MGR != 0
linear_mem_size = get_linear_mem_size();
#endif
dlen = linear_mem_size - dst;
/* dst boundary check */
#ifndef OS_ENABLE_HW_BOUND_CHECK
CHECK_BULK_MEMORY_OVERFLOW(dst, len, mdst);
#if WASM_ENABLE_SHARED_HEAP != 0
if (app_addr_in_shared_heap((uint64)dst, len))
dlen = shared_heap_end_off - dst + 1;
#endif
#else /* else of OS_ENABLE_HW_BOUND_CHECK */
#if WASM_ENABLE_SHARED_HEAP != 0
if (app_addr_in_shared_heap((uint64)dst, len)) {
shared_heap_addr_app_to_native((uint64)dst, mdst);
dlen = shared_heap_end_off - dst + 1;
}
else
#endif
@ -5832,6 +5824,7 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
/* skip src memidx */
frame_ip += 1;
#endif
// TODO: apply memidx
#if WASM_ENABLE_THREAD_MGR != 0
linear_mem_size = get_linear_mem_size();
#endif
@ -5851,15 +5844,21 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
}
#endif
#if WASM_ENABLE_MEMORY64 == 0
/*
* avoid unnecessary operations
*
* since dst and src both are valid indexes in the
* linear memory, mdst and msrc can't be NULL
*
* The spec. converts memory.copy into i32.load8 and
* i32.store8; the following are runtime-specific
* optimizations.
*
*/
if (len && mdst != msrc) {
/* allowing the destination and source to overlap */
bh_memmove_s(mdst, (uint32)dlen, msrc, (uint32)len);
#else
/* use memmove when memory64 is enabled since len
may be larger than UINT32_MAX */
memmove(mdst, msrc, len);
(void)dlen;
#endif
}
break;
}
case WASM_OP_MEMORY_FILL:

23
core/iwasm/interpreter/wasm_interp_fast.c
View File

@ -5163,7 +5163,6 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
{
uint32 dst, src, len;
uint8 *mdst, *msrc;
uint64 dlen;
len = POP_I32();
src = POP_I32();
@ -5173,15 +5172,9 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
linear_mem_size = get_linear_mem_size();
#endif
dlen = linear_mem_size - dst;
#ifndef OS_ENABLE_HW_BOUND_CHECK
CHECK_BULK_MEMORY_OVERFLOW(src, len, msrc);
CHECK_BULK_MEMORY_OVERFLOW(dst, len, mdst);
#if WASM_ENABLE_SHARED_HEAP != 0
if (app_addr_in_shared_heap((uint64)dst, len))
dlen = shared_heap_end_off - dst + 1;
#endif
#else /* else of OS_ENABLE_HW_BOUND_CHECK */
#if WASM_ENABLE_SHARED_HEAP != 0
if (app_addr_in_shared_heap((uint64)src, len))
@ -5197,7 +5190,6 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
#if WASM_ENABLE_SHARED_HEAP != 0
if (app_addr_in_shared_heap((uint64)dst, len)) {
shared_heap_addr_app_to_native((uint64)dst, mdst);
dlen = shared_heap_end_off - dst + 1;
}
else
#endif
@ -5208,8 +5200,21 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
}
#endif /* end of OS_ENABLE_HW_BOUND_CHECK */
/*
* avoid unnecessary operations
*
* since dst and src both are valid indexes in the
* linear memory, mdst and msrc can't be NULL
*
* The spec. converts memory.copy into i32.load8 and
* i32.store8; the following are runtime-specific
* optimizations.
*
*/
if (len && mdst != msrc) {
/* allowing the destination and source to overlap */
bh_memmove_s(mdst, (uint32)dlen, msrc, len);
memmove(mdst, msrc, len);
}
break;
}
case WASM_OP_MEMORY_FILL: