我想在 Go 中使用 WebAssembly 計算數(shù)組的總和：package mainimport ( "encoding/binary" "encoding/hex" "fmt" wasm "github.com/wasmerio/go-ext-wasm/wasmer")const length int32 = 4func main() { // Instantiate the module. wasmbyte, _ := wasm.ReadBytes("test.wasm") instance, _ := wasm.NewInstance(wasmbyte) defer instance.Close() hasmemory := instance.HasMemory() fmt.Println("it has memory:", (hasmemory)) a := []int32{1, 2, 3, 4} var i int32 var ptr [length]*int32 for i = 0; i < length; i++ { ptr[i] = &a[i] fmt.Printf("Value of a[%d] = %d\n", i, *ptr[i]) // pass int value // lengths := binary.LittleEndian.Uint32(a) // fmt.Printf("customLen=%d\n", int32(lengths)) // result := int32(lengths) allocateResult, err := instance.Exports["bar"](*ptr[i], length) if err != nil { fmt.Println("error is here", err) } binary.LittleEndian.PutUint32(instance.Memory.Data()[0:4], uint32(length)) inputPointer := allocateResult.ToI32() // Write the subject into the memory. memory := instance.Memory.Data()[inputPointer:] binary.LittleEndian.Uint32(memory) resp := hex.EncodeToString(memory) fmt.Println("resp:", resp) }}但這段代碼沒有給我預期的結果。我的代碼的邏輯是計算數(shù)組的總和。數(shù)組的值是在運行時給出的。我需要做哪些改變？我的 Rust 代碼看起來像這樣use std::os::raw::c_int;#[no_mangle]pub extern fn bar(my_array: *const c_int, length: c_int) -> *mut c_int{ let slice = unsafe { std::slice::from_raw_parts(my_array, length as usize) }; let resp: i32 = slice.iter().sum(); resp as *mut c_int}
1 回答
慕雪6442864
TA貢獻1812條經(jīng)驗 獲得超5個贊
將數(shù)據(jù)復制到 WebAssembly 內存（例如 WebAssembly 內存地址 0）：
a := []int32{10, 20, 30, 40}
// Copy data to wasm memory:
bytes := instance.Memory.Data()
for i, v := range a {
binary.LittleEndian.PutUint32(bytes[4*i:], uint32(v))
}
bar從 WebAssembly 實例獲取導出的函數(shù)：
bar := instance.Exports["bar"]
使用 WebAssembly 內存地址和長度調用導出的函數(shù)：
result, err := bar(0, 4)
if err != nil {
panic(err)
}
fmt.Println(result)
該main.go文件：
package main
import (
"encoding/binary"
"fmt"
wasm "github.com/wasmerio/go-ext-wasm/wasmer"
)
func main() {
// Instantiate the module.
wasmbyte, err := wasm.ReadBytes("test.wasm")
if err != nil {
panic(err)
}
instance, err := wasm.NewInstance(wasmbyte)
if err != nil {
panic(err)
}
defer instance.Close()
hasmemory := instance.HasMemory()
fmt.Println("it has memory:", hasmemory)
a := []int32{10, 20, 30, 40}
// Copy data to wasm memory:
bytes := instance.Memory.Data()
for i, v := range a {
binary.LittleEndian.PutUint32(bytes[4*i:], uint32(v))
}
bar := instance.Exports["bar"]
result, err := bar(0, 4)
if err != nil {
panic(err)
}
fmt.Println(result)
}
輸出（go run main.go）：
it has memory: true
100
以下src/lib.rs文件具有相同的 wasm 二進制文件（因為 Rust 切片只有指針和長度）：
#[no_mangle]
pub extern "C" fn bar(slice: &[i32]) -> i32 {
slice.iter().sum()
}
轉換為test.wasm：
rustc --target wasm32-unknown-unknown -O --crate-type=cdylib src/lib.rs -o test.wasm
輸出轉換為test.wat( wasm2wat test.wasm -o test.wat) 以查看函數(shù)$bar參數(shù) ( param i32 i32)：
(module
(type (;0;) (func (param i32 i32) (result i32)))
(func $bar (type 0) (param i32 i32) (result i32)
(local i32)
block ;; label = @1
local.get 1
br_if 0 (;@1;)
i32.const 0
return
end
local.get 1
i32.const 2
i32.shl
local.set 2
i32.const 0
local.set 1
loop ;; label = @1
local.get 0
i32.load
local.get 1
i32.add
local.set 1
local.get 0
i32.const 4
i32.add
local.set 0
local.get 2
i32.const -4
i32.add
local.tee 2
br_if 0 (;@1;)
end
local.get 1)
(table (;0;) 1 1 funcref)
(memory (;0;) 16)
(global (;0;) (mut i32) (i32.const 1048576))
(global (;1;) i32 (i32.const 1048576))
(global (;2;) i32 (i32.const 1048576))
(export "memory" (memory 0))
(export "bar" (func $bar))
(export "__data_end" (global 1))
(export "__heap_base" (global 2)))
- 1 回答
- 0 關注
- 137 瀏覽
添加回答
舉報
0/150
提交
取消