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Upgrade to WasmEdge 0.14.0

Due to the WasmEdge C API breaking changes, this document shows the guideline for programming with WasmEdge C API to upgrade from the 0.13.5 to the 0.14.0 version.

Concepts​

  1. Introduced new APIs for WasmEdge_ValType struct and integrated with WASM values.

    The WasmEdge_ValType becomes a struct for supporting the typed function reference proposal and GC proposal.

    The enumerations enum WasmEdge_ValType and enum WasmEdge_RefType are renamed as enum WasmEdge_ValTypeCode and enum WasmEdge_RefTypeCode. Developers should use the following APIs to generate the WasmEdge_ValType structures:

    • WasmEdge_ValTypeGenI32()
    • WasmEdge_ValTypeGenI64()
    • WasmEdge_ValTypeGenF32()
    • WasmEdge_ValTypeGenF64()
    • WasmEdge_ValTypeGenV128()
    • WasmEdge_ValTypeGenFuncRef()
    • WasmEdge_ValTypeGenExternRef()

    And there's new APIs for checking the value types from the WasmEdge_ValType struct:

    • WasmEdge_ValTypeIsEqual()
    • WasmEdge_ValTypeIsI32()
    • WasmEdge_ValTypeIsI64()
    • WasmEdge_ValTypeIsF32()
    • WasmEdge_ValTypeIsF64()
    • WasmEdge_ValTypeIsV128()
    • WasmEdge_ValTypeIsFuncRef() for checking whether a type is a nullable or non-nullable function reference.
    • WasmEdge_ValTypeIsExternRef() for checking whether a type is a nullable or non-nullable external reference.
    • WasmEdge_ValTypeIsRef() for checking whether a type is a nullable or non-nullable reference.
    • WasmEdge_ValTypeIsRefNull() for checking whether a type is a nullable reference.

    The following APIs using value types as parameters and return values are affected:

    • WasmEdge_FunctionTypeCreate()
    • WasmEdge_FunctionTypeGetParameters()
    • WasmEdge_FunctionTypeGetReturns()
    • WasmEdge_TableTypeCreate()
    • WasmEdge_TableTypeGetRefType(): returns a WasmEdge_ValType, which is guaranteed as a reference type.
    • WasmEdge_GlobalTypeCreate()
    • WasmEdge_GlobalTypeGetValType()

    The following API is deleted:

    • WasmEdge_ValueGenNullRef(): please use WasmEdge_ValueGenFuncRef() or WasmEdge_ValueGenExternRef() instead.

  2. Introduced WasmEdge_Bytes for loading and serialization.

    Rathar than the raw buffer, we recommand developers to use WasmEdge_Bytes and related APIs to manage the input and output buffer for loading and serializing a WASM binary.

    • WasmEdge_BytesCreate(): create a WasmEdge_Bytes and copy from buffer with size.
    • WasmEdge_BytesWrap(): wrap a WasmEdge_Bytes onto a buffer with size.
    • WasmEdge_BytesDelete(): delete a allocated WasmEdge_Bytes.

    For the old APIs, we also introduced the WasmEdge_Bytes version. The old APIs will be deprecated in the future.

    • WasmEdge_CompilerCompileFromBytes(): this API has the same behavior as WasmEdge_CompilerCompileFromBuffer().
    • WasmEdge_LoaderParseFromBytes(): this API has the same behavior as WasmEdge_LoaderParseFromBuffer().
    • WasmEdge_LoaderSerializeASTModule(): this API outputs a WasmEdge_Bytes, and the result should be deleted by the caller.
    • WasmEdge_VMRegisterModuleFromBytes(): this API has the same behavior as WasmEdge_VMRegisterModuleFromBuffer().
    • WasmEdge_VMRunWasmFromBytes(): this API has the same behavior as WasmEdge_VMRunWasmFromBuffer().
    • WasmEdge_VMAsyncRunWasmFromBytes(): this API has the same behavior as WasmEdge_VMAsyncRunWasmFromBuffer().
    • WasmEdge_VMLoadWasmFromBytes(): this API has the same behavior as WasmEdge_VMLoadWasmFromBuffer().

  3. APIs of instances changed for the new proposal.

    For supporting the typed function reference proposal and GC proposal proposal, the new API of table instance is needed for the defaultable reference values.

    • WasmEdge_TableInstanceCreateWithInit(): developers can use this API to create a table instance with default value.

    Furthermore, for type matching and mutation checking, the result error is needed.

    • WasmEdge_GlobalInstanceSetValue(): returns WasmEdge_Result for result, and error occurs when type not matched or mutation failed.

Value type creation and checking​

Before the version 0.13.5, the WasmEdge_ValType is an enum:

enum WasmEdge_ValType ParamList[2] = {WasmEdge_ValType_I32,
                                      WasmEdge_ValType_I32};
enum WasmEdge_ValType ReturnList[1] = {WasmEdge_ValType_I32};
/* Create a function type: {i32, i32} -> {i32}. */
WasmEdge_FunctionTypeContext *HostFType =
    WasmEdge_FunctionTypeCreate(ParamList, 2, ReturnList, 1);

WasmEdge_FunctionTypeDelete(HostType);

After 0.14.0, developers should use the APIs to generate the WasmEdge_ValType. This affects the APIs list above.

WasmEdge_ValType ParamList[2] = {WasmEdge_ValTypeGenI32(), WasmEdge_ValTypeGenI32()};
WasmEdge_ValType ReturnList[1] = {WasmEdge_ValTypeGenI32()};
/* Create a function type: {i32, i32} -> {i32}. */
WasmEdge_FunctionTypeContext *HostFType =
    WasmEdge_FunctionTypeCreate(ParamList, 2, ReturnList, 1);

WasmEdge_FunctionTypeDelete(HostType);

Use packaged buffer for loading​

Before the version 0.13.5, developers can use the raw buffer to load WASM binary:

uint8_t WASM[] = {/* WASM header */
                  0x00, 0x61, 0x73, 0x6D, 0x01, 0x00, 0x00, 0x00,
                  /* Type section */
                  0x01, 0x07, 0x01,
                  /* function type {i32, i32} -> {i32} */
                  0x60, 0x02, 0x7F, 0x7F, 0x01, 0x7F,
                  /* Import section */
                  0x02, 0x13, 0x01,
                  /* module name: "extern" */
                  0x06, 0x65, 0x78, 0x74, 0x65, 0x72, 0x6E,
                  /* extern name: "func-add" */
                  0x08, 0x66, 0x75, 0x6E, 0x63, 0x2D, 0x61, 0x64, 0x64,
                  /* import desc: func 0 */
                  0x00, 0x00,
                  /* Function section */
                  0x03, 0x02, 0x01, 0x00,
                  /* Export section */
                  0x07, 0x0A, 0x01,
                  /* export name: "addTwo" */
                  0x06, 0x61, 0x64, 0x64, 0x54, 0x77, 0x6F,
                  /* export desc: func 0 */
                  0x00, 0x01,
                  /* Code section */
                  0x0A, 0x0A, 0x01,
                  /* code body */
                  0x08, 0x00, 0x20, 0x00, 0x20, 0x01, 0x10, 0x00, 0x0B};

WasmEdge_LoaderContext *LoadCxt = WasmEdge_LoaderCreate(NULL);
WasmEdge_ASTModuleContext *ASTCxt = NULL;
WasmEdge_Result Res;

/* Load WASM or compiled-WASM from the buffer. */
Res = WasmEdge_LoaderParseFromBuffer(LoadCxt, &ASTCxt, WASM, sizeof(WASM));
if (!WasmEdge_ResultOK(Res)) {
  printf("Loading phase failed: %s\n", WasmEdge_ResultGetMessage(Res));
}
/* The output AST module context should be destroyed. */
WasmEdge_ASTModuleDelete(ASTCxt);

WasmEdge_LoaderDelete(LoadCxt);

After 0.14.0, we recommanded developers use the WasmEdge_Bytes related APIs instead. The old APIs still work, but will be deprecated in the future.

uint8_t WASM[] = {/* WASM header */
                  0x00, 0x61, 0x73, 0x6D, 0x01, 0x00, 0x00, 0x00,
                  /* Type section */
                  0x01, 0x07, 0x01,
                  /* function type {i32, i32} -> {i32} */
                  0x60, 0x02, 0x7F, 0x7F, 0x01, 0x7F,
                  /* Import section */
                  0x02, 0x13, 0x01,
                  /* module name: "extern" */
                  0x06, 0x65, 0x78, 0x74, 0x65, 0x72, 0x6E,
                  /* extern name: "func-add" */
                  0x08, 0x66, 0x75, 0x6E, 0x63, 0x2D, 0x61, 0x64, 0x64,
                  /* import desc: func 0 */
                  0x00, 0x00,
                  /* Function section */
                  0x03, 0x02, 0x01, 0x00,
                  /* Export section */
                  0x07, 0x0A, 0x01,
                  /* export name: "addTwo" */
                  0x06, 0x61, 0x64, 0x64, 0x54, 0x77, 0x6F,
                  /* export desc: func 0 */
                  0x00, 0x01,
                  /* Code section */
                  0x0A, 0x0A, 0x01,
                  /* code body */
                  0x08, 0x00, 0x20, 0x00, 0x20, 0x01, 0x10, 0x00, 0x0B};

WasmEdge_LoaderContext *LoadCxt = WasmEdge_LoaderCreate(NULL);
WasmEdge_ASTModuleContext *ASTCxt = NULL;
WasmEdge_Result Res;
/* Wrap onto the `WASM`. */
WasmEdge_Bytes Bytes = WasmEdge_BytesWrap(WASM, sizeof(WASM));
/*
 * If developers want to copy from buffer, use the `WasmEdge_BytesCreate()`
 * instead. The created `WasmEdge_Bytes` should be destroyed.
 */

/* Load WASM or compiled-WASM from the buffer. */
Res = WasmEdge_LoaderParseFromBytes(LoadCxt, &ASTCxt, Bytes);
if (!WasmEdge_ResultOK(Res)) {
  printf("Loading phase failed: %s\n", WasmEdge_ResultGetMessage(Res));
}
/* The output AST module context should be destroyed. */
WasmEdge_ASTModuleDelete(ASTCxt);

WasmEdge_LoaderDelete(LoadCxt);