Go API v0.13.4 Documentation

The following are the guides to working with the WasmEdge-Go SDK.

Getting Started

The WasmEdge-go requires golang version >= 1.16. Please check your golang version before installation. Developers can download golang here.

$ go version
go version go1.16.5 linux/amd64

WasmEdge Installation

Developers must install the WasmEdge shared library with the same WasmEdge-go release or pre-release version.

curl -sSf https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | bash -s -- -v 0.13.4

For the developers need the TensorFlow or Image extension for WasmEdge-go, please install the WasmEdge with extensions:

curl -sSf https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | bash -s -- -e tf,image -v 0.13.4

Noticed that the TensorFlow and Image extensions are only for the Linux platforms. After installation, developers can use the source command to update the include and linking searching path.

Get WasmEdge-go

After the WasmEdge installation, developers can get the WasmEdge-go package and build it in your Go project directory.

go get github.com/second-state/WasmEdge-go/wasmedge@v0.13.4
go build

備註

The WasmEdge-Go version number should match the installed WasmEdge version.

Example Repository

Developers can refer to the example repository for the WasmEdge-Go examples.

WasmEdge-go Basics

In this partition, we will introduce the utilities and concepts of WasmEdge-go APIs and data structures.

Version

The Version related APIs provide developers to check for the installed WasmEdge shared library version.

import "github.com/second-state/WasmEdge-go/wasmedge"

verstr := wasmedge.GetVersion() // Will be `string` of WasmEdge version.
vermajor := wasmedge.GetVersionMajor() // Will be `uint` of WasmEdge major version number.
verminor := wasmedge.GetVersionMinor() // Will be `uint` of WasmEdge minor version number.
verpatch := wasmedge.GetVersionPatch() // Will be `uint` of WasmEdge patch version number.

Logging Settings

The wasmedge.SetLogErrorLevel() and wasmedge.SetLogDebugLevel() APIs can set the logging system to debug level or error level. By default, the error level is set, and the debug info is hidden.

Developers can also use the wasmedge.SetLogOff() API to disable all logging.

Value Types

In WasmEdge-go, the APIs will automatically do the conversion for the built-in types, and implement the data structure for the reference types.

Number types: i32, i64, f32, and f64
- Convert the uint32 and int32 to i32 automatically when passing a value into WASM.
- Convert the uint64 and int64 to i64 automatically when passing a value into WASM.
- Convert the uint and int to i32 automatically when passing a value into WASM in 32-bit system.
- Convert the uint and int to i64 automatically when passing a value into WASM in 64-bit system.
- Convert the float32 to f32 automatically when passing a value into WASM.
- Convert the float64 to f64 automatically when passing a value into WASM.
- Convert the i32 from WASM to int32 when getting a result.
- Convert the i64 from WASM to int64 when getting a result.
- Convert the f32 from WASM to float32 when getting a result.
- Convert the f64 from WASM to float64 when getting a result.
Number type: v128 for the SIMD proposal
Developers should use the wasmedge.NewV128() to generate a v128 value, and use the wasmedge.GetV128() to get the value.
```
val := wasmedge.NewV128(uint64(1234), uint64(5678))
high, low := val.GetVal()
// `high` will be uint64(1234), `low` will be uint64(5678)
```

Reference types: FuncRef and ExternRef for the Reference-Types proposal

var funccxt *wasmedge.Function = ... // Create or get function object.
funcref := wasmedge.NewFuncRef(funccxt)
// Create a `FuncRef` with the function object.

num := 1234
// `num` is a `int`.
externref := wasmedge.NewExternRef(&num)
// Create an `ExternRef` which reference to the `num`.
num = 5678
// Modify the `num` to 5678.
numref := externref.GetRef().(*int)
// Get the original reference from the `ExternRef`.
fmt.Println(*numref)
// Will print `5678`.
numref.Release()
// Should call the `Release` method.

Results

The Result object specifies the execution status. Developers can use the Error() function to get the error message.

// Assume that `vm` is a `wasmedge.VM` object.
res, err = vm.Execute(...) // Ignore the detail of parameters.
// Assume that `res, err` are the return values for executing a function with `vm`.
if err != nil {
  fmt.Println("Error message:", err.Error())
  category := err.GetErrorCategory()
  // The `category` will be `wasmedge.ErrCategory_WASM`.
}

userdef_err := wasmedge.NewResult(wasmedge.ErrCategory_UserLevel, 123456)
// Generate the user-defined error with code.
code := userdef_err.GetCode()
// The `Code` will be 123456.

Contexts And Their Life Cycles

The objects, such as VM, Store, and Function, etc., are composed of Contexts in the WasmEdge shared library. All of the contexts can be created by calling the corresponding New APIs, developers should also call the corresponding Release functions of the contexts to release the resources. Noticed that it's not necessary to call the Release functions for the contexts which are retrieved from other contexts but not created from the New APIs.

// Create a Configure.
conf := wasmedge.NewConfigure()
// Release the `conf` immediately.
conf.Release()

The details of other contexts will be introduced later.

WASM Data Structures

The WASM data structures are used for creating instances or can be queried from instance contexts. The details of instances creation will be introduced in the Instances.

Limit

The Limit struct presents the minimum and maximum value data structure.

lim1 := wasmedge.NewLimit(12)
fmt.Println(lim1.HasMax())
// Will print `false`.
fmt.Println(lim1.GetMin())
// Will print `12`.

lim2 := wasmedge.NewLimitWithMax(15, 50)
fmt.Println(lim2.HasMax())
// Will print `true`.
fmt.Println(lim2.GetMin())
// Will print `15`.
fmt.Println(lim2.GetMax())
// Will print `50`.

For the thread proposal, the Limit struct also supports the shared memory description.

lim3 := wasmedge.NewLimitShared(20)
fmt.Println(lim3.HasMax())
// Will print `false`.
fmt.Println(lim3.IsShared())
// Will print `true`.
fmt.Println(lim3.GetMin())
// Will print `20`.

lim4 := wasmedge.NewLimitSharedWithMax(30, 40)
fmt.Println(lim4.HasMax())
// Will print `true`.
fmt.Println(lim4.IsShared())
// Will print `true`.
fmt.Println(lim4.GetMin())
// Will print `30`.
fmt.Println(lim4.GetMax())
// Will print `40`.

Function type context

The FunctionType is an object holds the function type context and used for the Function creation, checking the value types of a Function instance, or getting the function type with function name from VM. Developers can use the FunctionType APIs to get the parameter or return value types information.

functype := wasmedge.NewFunctionType(
  []wasmedge.ValType{
    wasmedge.ValType_ExternRef,
    wasmedge.ValType_I32,
    wasmedge.ValType_I64,
  }, []wasmedge.ValType{
    wasmedge.ValType_F32,
    wasmedge.ValType_F64,
  })

plen := functype.GetParametersLength()
// `plen` will be 3.
rlen := functype.GetReturnsLength()
// `rlen` will be 2.
plist := functype.GetParameters()
// `plist` will be `[]wasmedge.ValType{wasmedge.ValType_ExternRef, wasmedge.ValType_I32, wasmedge.ValType_I64}`.
rlist := functype.GetReturns()
// `rlist` will be `[]wasmedge.ValType{wasmedge.ValType_F32, wasmedge.ValType_F64}`.

functype.Release()

Table type context

The TableType is an object holds the table type context and used for Table instance creation or getting information from Table instances.

lim := wasmedge.NewLimit(12)
tabtype := wasmedge.NewTableType(wasmedge.RefType_ExternRef, lim)

rtype := tabtype.GetRefType()
// `rtype` will be `wasmedge.RefType_ExternRef`.
getlim := tabtype.GetLimit()
// `getlim` will be the same value as `lim`.

tabtype.Release()

Memory type context

The MemoryType is an object holds the memory type context and used for Memory instance creation or getting information from Memory instances.

lim := wasmedge.NewLimit(1)
memtype := wasmedge.NewMemoryType(lim)

getlim := memtype.GetLimit()
// `getlim` will be the same value as `lim`.

memtype.Release()

Global type context

The GlobalType is an object holds the global type context and used for Global instance creation or getting information from Global instances.

globtype := wasmedge.NewGlobalType(wasmedge.ValType_F64, wasmedge.ValMut_Var)

vtype := globtype.GetValType()
// `vtype` will be `wasmedge.ValType_F64`.
vmut := globtype.GetMutability()
// `vmut` will be `wasmedge.ValMut_Var`.

globtype.Release()

Import type context

The ImportType is an object holds the import type context and used for getting the imports information from a AST Module. Developers can get the external type (function, table, memory, or global), import module name, and external name from an ImportType object. The details about querying ImportType objects will be introduced in the AST Module.

var ast *wasmedge.AST = ...
// Assume that `ast` is returned by the `Loader` for the result of loading a WASM file.
imptypelist := ast.ListImports()
// Assume that `imptypelist` is an array listed from the `ast` for the imports.

for i, imptype := range imptypelist {
  exttype := imptype.GetExternalType()
  // The `exttype` must be one of `wasmedge.ExternType_Function`, `wasmedge.ExternType_Table`,
  // wasmedge.ExternType_Memory`, or `wasmedge.ExternType_Global`.

  modname := imptype.GetModuleName()
  extname := imptype.GetExternalName()
  // Get the module name and external name of the imports.

  extval := imptype.GetExternalValue()
  // The `extval` is the type of `interface{}` which indicates one of `*wasmedge.FunctionType`,
  // `*wasmedge.TableType`, `*wasmedge.MemoryType`, or `*wasmedge.GlobalType`.
}

Export type context

The ExportType is an object holds the export type context is used for getting the exports information from a AST Module. Developers can get the external type (function, table, memory, or global) and external name from an Export Type context. The details about querying ExportType objects will be introduced in the AST Module.

var ast *wasmedge.AST = ...
// Assume that `ast` is returned by the `Loader` for the result of loading a WASM file.
exptypelist := ast.ListExports()
// Assume that `exptypelist` is an array listed from the `ast` for the exports.

for i, exptype := range exptypelist {
  exttype := exptype.GetExternalType()
  // The `exttype` must be one of `wasmedge.ExternType_Function`, `wasmedge.ExternType_Table`,
  // wasmedge.ExternType_Memory`, or `wasmedge.ExternType_Global`.

  extname := exptype.GetExternalName()
  // Get the external name of the exports.

  extval := exptype.GetExternalValue()
  // The `extval` is the type of `interface{}` which indicates one of `*wasmedge.FunctionType`,
  // `*wasmedge.TableType`, `*wasmedge.MemoryType`, or `*wasmedge.GlobalType`.
}

Async

After calling the asynchronous execution APIs, developers will get the wasmedge.Async object. Developers own the object and should call the (*Async).Release() API to release it.

Get the execution result of the asynchronous execution
Developers can use the (*Async).GetResult() API to block and wait for getting the return values. This function will block and wait for the execution. If the execution has finished, this function will return immediately. If the execution failed, this function will return an error.
```
async := ... // Ignored. Asynchronous execute a function.

// Blocking and waiting for the execution and get the return values.
res, err := async.GetResult()
async.Release()
```

Wait for the asynchronous execution with timeout settings

Besides waiting until the end of execution, developers can set the timeout to wait for.

async := ... // Ignored. Asynchronous execute a function.

// Blocking and waiting for the execution with the timeout(ms).
isend := async.WaitFor(1000)
if isend {
  res, err := async.GetResult()
  // ...
} else {
  async.Cancel()
  _, err := async.GetResult()
  // The error message in `err` will be "execution interrupted".
}
async.Release()

Configurations

The configuration object, wasmedge.Configure, manages the configurations for Loader, Validator, Executor, VM, and Compiler. Developers can adjust the settings about the proposals, VM host pre-registrations (such as WASI), and AOT compiler options, and then apply the Configure object to create other runtime objects.

Proposals

WasmEdge supports turning on or off the WebAssembly proposals. This configuration is effective in any contexts created with the Configure object.

const (
  IMPORT_EXPORT_MUT_GLOBALS         = Proposal(C.WasmEdge_Proposal_ImportExportMutGlobals)
  NON_TRAP_FLOAT_TO_INT_CONVERSIONS = Proposal(C.WasmEdge_Proposal_NonTrapFloatToIntConversions)
  SIGN_EXTENSION_OPERATORS          = Proposal(C.WasmEdge_Proposal_SignExtensionOperators)
  MULTI_VALUE                       = Proposal(C.WasmEdge_Proposal_MultiValue)
  BULK_MEMORY_OPERATIONS            = Proposal(C.WasmEdge_Proposal_BulkMemoryOperations)
  REFERENCE_TYPES                   = Proposal(C.WasmEdge_Proposal_ReferenceTypes)
  SIMD                              = Proposal(C.WasmEdge_Proposal_SIMD)
  TAIL_CALL                         = Proposal(C.WasmEdge_Proposal_TailCall)
  ANNOTATIONS                       = Proposal(C.WasmEdge_Proposal_Annotations)
  MEMORY64                          = Proposal(C.WasmEdge_Proposal_Memory64)
  EXCEPTION_HANDLING                = Proposal(C.WasmEdge_Proposal_ExceptionHandling)
  EXTENDED_CONST                    = Proposal(C.WasmEdge_Proposal_ExtendedConst)
  THREADS                           = Proposal(C.WasmEdge_Proposal_Threads)
  FUNCTION_REFERENCES               = Proposal(C.WasmEdge_Proposal_FunctionReferences)
)

Developers can add or remove the proposals into the Configure object.

// By default, the following proposals have turned on initially:
// * IMPORT_EXPORT_MUT_GLOBALS
// * NON_TRAP_FLOAT_TO_INT_CONVERSIONS
// * SIGN_EXTENSION_OPERATORS
// * MULTI_VALUE
// * BULK_MEMORY_OPERATIONS
// * REFERENCE_TYPES
// * SIMD
// For the current WasmEdge version, the following proposals are supported:
// * TAIL_CALL
// * MULTI_MEMORIES
// * THREADS
// * EXTENDED_CONST
conf := wasmedge.NewConfigure()
// Developers can also pass the proposals as parameters:
// conf := wasmedge.NewConfigure(wasmedge.SIMD, wasmedge.BULK_MEMORY_OPERATIONS)
conf.AddConfig(wasmedge.SIMD)
conf.RemoveConfig(wasmedge.REFERENCE_TYPES)
is_bulkmem := conf.HasConfig(wasmedge.BULK_MEMORY_OPERATIONS)
// The `is_bulkmem` will be `true`.
conf.Release()

Host registrations
This configuration is used for the VM context to turn on the WASI supports and only effective in VM contexts.
The element of this enum is reserved for the other built-in host functions (such as wasi-socket) in the future.
```
const (
  WASI = HostRegistration(C.WasmEdge_HostRegistration_Wasi)
)
```
The details will be introduced in the preregistrations of VM context.
```
conf := wasmedge.NewConfigure()
// Developers can also pass the proposals as parameters:
// conf := wasmedge.NewConfigure(wasmedge.WASI)
conf.AddConfig(wasmedge.WASI)
conf.Release()
```
Maximum memory pages
Developers can limit the page size of memory instances by this configuration. When growing the page size of memory instances in WASM execution and exceeding the limited size, the page growing will fail. This configuration is only effective in the Executor and VM objects.
```
conf := wasmedge.NewConfigure()

pagesize := conf.GetMaxMemoryPage()
// By default, the maximum memory page size in each memory instances is 65536.
conf.SetMaxMemoryPage(1234)
pagesize = conf.GetMaxMemoryPage()
// `pagesize` will be 1234.

conf.Release()
```

Forcibly interpreter mode

If developers want to execute the WASM file or the AOT compiled WASM in interpreter mode forcibly, they can turn on the configuration.

conf := wasmedge.NewConfigure()

is_forceinterp := conf.IsForceInterpreter()
// By default, the `is_forceinterp` will be `false`.
conf.SetForceInterpreter(true)
is_forceinterp = conf.IsForceInterpreter()
/* The `is_forceinterp` will be `true`. */

conf.Release()

AOT compiler options

The AOT compiler options configure the behavior about optimization level, output format, dump IR, and generic binary.

const (
  // Disable as many optimizations as possible.
  CompilerOptLevel_O0 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O0)
  // Optimize quickly without destroying debuggability.
  CompilerOptLevel_O1 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O1)
  // Optimize for fast execution as much as possible without triggering significant incremental compile time or code size growth.
  CompilerOptLevel_O2 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O2)
  // Optimize for fast execution as much as possible.
  CompilerOptLevel_O3 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O3)
  // Optimize for small code size as much as possible without triggering significant incremental compile time or execution time slowdowns.
  CompilerOptLevel_Os = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_Os)
  // Optimize for small code size as much as possible.
  CompilerOptLevel_Oz = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_Oz)
)

const (
  // Native dynamic library format.
  CompilerOutputFormat_Native = CompilerOutputFormat(C.WasmEdge_CompilerOutputFormat_Native)
  // WebAssembly with AOT compiled codes in custom section.
  CompilerOutputFormat_Wasm = CompilerOutputFormat(C.WasmEdge_CompilerOutputFormat_Wasm)
)

These configurations are only effective in Compiler contexts.

conf := wasmedge.NewConfigure()

// By default, the optimization level is O3.
conf.SetCompilerOptimizationLevel(wasmedge.CompilerOptLevel_O2)
// By default, the output format is universal WASM.
conf.SetCompilerOutputFormat(wasmedge.CompilerOutputFormat_Native)
// By default, the dump IR is `false`.
conf.SetCompilerDumpIR(true)
// By default, the generic binary is `false`.
conf.SetCompilerGenericBinary(true)

conf.Release()

Statistics options

The statistics options configure the behavior about instruction counting, cost measuring, and time measuring in both runtime and AOT compiler. These configurations are effective in Compiler, VM, and Executor objects.

conf := wasmedge.NewConfigure()

// By default, the instruction counting is `false` when running a compiled-WASM or a pure-WASM.
conf.SetStatisticsInstructionCounting(true)
// By default, the cost measurement is `false` when running a compiled-WASM or a pure-WASM.
conf.SetStatisticsTimeMeasuring(true)
// By default, the time measurement is `false` when running a compiled-WASM or a pure-WASM.
conf.SetStatisticsCostMeasuring(true)

conf.Release()

Statistics

The statistics object, wasmedge.Statistics, provides the instruction counter, cost summation, and cost limitation at runtime.

Before using statistics, the statistics configuration must be set. Otherwise, the return values of calling statistics are undefined behaviour.

Instruction counter
The instruction counter can help developers to profile the performance of WASM running. Developers can retrieve the Statistics object from the VM object, or create a new one for the Executor creation. The details will be introduced in the next partitions.
```
stat := wasmedge.NewStatistics()
// ... After running the WASM functions with the `Statistics` object

count := stat.GetInstrCount()
ips := stat.GetInstrPerSecond()
stat.Release()
```

Cost table

The cost table is to accumulate the cost of instructions with their weights. Developers can set the cost table array (the indices are the byte code value of instructions, and the values are the cost of instructions) into the Statistics object. If the cost limit value is set, the execution will return the cost limit exceeded error immediately when exceeds the cost limit in runtime.

stat := wasmedge.NewStatistics()

costtable := []uint64{
  0, 0,
  10, /* 0x02: Block */
  11, /* 0x03: Loop */
  12, /* 0x04: If */
  12, /* 0x05: Else */
  0, 0, 0, 0, 0, 0,
  20, /* 0x0C: Br */
  21, /* 0x0D: Br_if */
  22, /* 0x0E: Br_table */
  0,
}
// Developers can set the costs of each instruction. The value not covered will be 0.

WasmEdge_StatisticsSetCostTable(StatCxt, CostTable, 16);
stat.SetCostTable()
stat.SetCostLimit(5000000)

// ... After running the WASM functions with the `Statistics` object
cost := stat.GetTotalCost()
stat.Release()

WasmEdge VM

In this partition, we will introduce the functions of wasmedge.VM object and show examples of executing WASM functions.

WASM Execution Example With VM Object

The following shows the example of running the WASM for getting the Fibonacci. This example uses the WASM file fibonacci.wasm converted from the text format fibonacci.wat.

(module
  (export "fib" (func $fib))
  (func $fib (param $n i32) (result i32)
    (if
      (i32.lt_s (get_local $n)(i32.const 2))
      (return (i32.const 1))
    )
    (return
      (i32.add
        (call $fib (i32.sub (get_local $n)(i32.const 2)))
        (call $fib (i32.sub (get_local $n)(i32.const 1)))
      )
    )
  )
)

Run WASM functions rapidly

Create a new Go project first:

mkdir wasmedge_test && cd wasmedge_test
go mod init wasmedge_test

Assume that the WASM file fibonacci.wasm from the text format fibonacci.wat is copied into the current wasmedge_test directory, and create and edit the Go file main.go as following:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  // Set the logging level.
  wasmedge.SetLogErrorLevel()

  // Create the configure context and add the WASI support.
  // This step is not necessary unless you need WASI support.
  conf := wasmedge.NewConfigure(wasmedge.WASI)
  // Create VM with the configure.
  vm := wasmedge.NewVMWithConfig(conf)

  res, err := vm.RunWasmFile("fibonacci.wasm", "fib", uint32(21))
  if err == nil {
    fmt.Println("Get fibonacci[21]:", res[0].(int32))
  } else {
    fmt.Println("Run failed:", err.Error())
  }

  vm.Release()
  conf.Release()
}

Then you can build and run the Golang application with the WasmEdge Golang SDK: (the 21 Fibonacci number is 17711 in 0-based index)

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
Get fibonacci[21]: 17711

Instantiate and run WASM functions manually

Besides the above example, developers can run the WASM functions step-by-step with VM object APIs:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  // Set the logging level.
  wasmedge.SetLogErrorLevel()

  // Create VM.
  vm := wasmedge.NewVM()
  var err error
  var res []interface{}

  // Step 1: Load WASM file.
  err = vm.LoadWasmFile("fibonacci.wasm")
  if err != nil {
    fmt.Println("Load WASM from file FAILED:", err.Error())
    return
  }

  // Step 2: Validate the WASM module.
  err = vm.Validate()
  if err != nil {
    fmt.Println("Validation FAILED:", err.Error())
    return
  }

  // Step 3: Instantiate the WASM module.
  err = vm.Instantiate()
  // Developers can load, validate, and instantiate another WASM module
  // to replace the instantiated one. In this case, the old module will
  // be cleared, but the registered modules are still kept.
  if err != nil {
    fmt.Println("Instantiation FAILED:", err.Error())
    return
  }

  // Step 4: Execute WASM functions. Parameters: (funcname, args...)
  res, err = vm.Execute("fib", uint32(25))
  // Developers can execute functions repeatedly after instantiation.
  if err == nil {
    fmt.Println("Get fibonacci[25]:", res[0].(int32))
  } else {
    fmt.Println("Run failed:", err.Error())
  }

  vm.Release()
}

Then you can build and run: (the 25th Fibonacci number is 121393 in 0-based index)

$ go build
$ ./wasmedge_test
Get fibonacci[25]: 121393

The following graph explains the status of the VM object.

                       |========================|
              |------->|      VM: Initiated     |
              |        |========================|
              |                    |
              |                 LoadWasm
              |                    |
              |                    v
              |        |========================|
              |--------|       VM: Loaded       |<-------|
              |        |========================|        |
              |              |            ^              |
              |         Validate          |              |
          Cleanup            |          LoadWasm         |
              |              v            |            LoadWasm
              |        |========================|        |
              |--------|      VM: Validated     |        |
              |        |========================|        |
              |              |            ^              |
              |      Instantiate          |              |
              |              |          RegisterModule   |
              |              v            |              |
              |        |========================|        |
              |--------|    VM: Instantiated    |--------|
                       |========================|
                             |            ^
                             |            |
                             --------------
                Instantiate, Execute, ExecuteRegistered,
                ExecuteBindgen, ExecuteBindgenRegistered

The status of the VM context would be Inited when created. After loading WASM successfully, the status will be Loaded. After validating WASM successfully, the status will be Validated. After instantiating WASM successfully, the status will be Instantiated, and developers can invoke functions. Developers can register WASM or import objects in any status, but they should instantiate WASM again. Developers can also load WASM in any status, and they should validate and instantiate the WASM module before function invocation. When in the Instantiated status, developers can instantiate the WASM module again to reset the old WASM runtime structures.

VM Creations

The VM creation APIs accepts the Configure object and the Store object. Noticed that if the VM created with the outside Store object, the VM will execute WASM on that Store object. If the Store object is set into multiple VM objects, it may causes data conflict when in execution. The details of the Store object will be introduced in Store.

conf := wasmedge.NewConfigure()
store := wasmedge.NewStore()

// Create a VM with default configure and store.
vm := wasmedge.NewVM()
vm.Release()

// Create a VM with the specified configure and default store.
vm = wasmedge.NewVMWithConfig(conf)
vm.Release()

// Create a VM with the default configure and specified store.
vm = wasmedge.NewVMWithStore(store)
vm.Release()

// Create a VM with the specified configure and store.
vm = wasmedge.NewVMWithConfigAndStore(conf, store)
vm.Release()

conf.Release()
store.Release()

Built-in Host Modules and Plug-in Preregistrations

WasmEdge provides the following built-in host modules and plug-in pre-registrations.

WASI (WebAssembly System Interface)

Developers can turn on the WASI support for VM in the Configure object.

conf := wasmedge.NewConfigure(wasmedge.WASI)
// Or you can set the `wasmedge.WASI` into the configure object through `(*Configure).AddConfig`.
vm := wasmedge.NewVMWithConfig(conf)
conf.Release()

// The following API can retrieve the built-in registered module instances from the VM object.
// This API will return `nil` if the corresponding configuration is not set when creating the VM object.
wasiconf := vm.GetImportModule(wasmedge.WASI)
// Initialize the WASI.
wasiconf.InitWasi(/* ... ignored */)

vm.Release()

And also can create the WASI import object from API. The details will be introduced in the Host Functions and the Host Module Registrations.

Plug-ins
There may be several plug-ins in the default plug-in paths if users installed WasmEdge plug-ins by the installer.
Before using the plug-ins, developers should load the plug-ins from paths.
The VM object will automatically create and register the module of the loaded plug-ins when creation. Furthermore, the following host modules will be mocked if the plug-in not loaded:
- wasi_ephemeral_crypto_asymmetric_common (for the WASI-Crypto)
- wasi_ephemeral_crypto_common (for the WASI-Crypto)
- wasi_ephemeral_crypto_kx (for the WASI-Crypto)
- wasi_ephemeral_crypto_signatures (for the WASI-Crypto)
- wasi_ephemeral_crypto_symmetric (for the WASI-Crypto)
- wasi_ephemeral_nn
- wasi_snapshot_preview1
- wasmedge_httpsreq
- wasmedge_process
- wasi:logging/logging (for the WASI-Logging)
When the WASM want to invoke these host functions but the corresponding plug-in not installed, WasmEdge will print the error message and return an error.
```
// Load the plug-ins in the default paths first.
wasmedge.LoadPluginDefaultPaths()

// Create the VM object with the WASI configuration.
conf := wasmedge.NewConfigure(wasmedge.WASI)
vm := wasmedge.NewVMWithConfig(conf)
conf.Release()

// The following API can retrieve the registered modules in the VM objects, includes the built-in WASI and the plug-ins.
// This API will return `NULL` if the module instance not found.

// The `wasimodule` will not be `nil` because the configuration was set.
wasimodule := vm.GetRegisteredModule("wasi_snapshot_preview1")

// The `wasinnmodule` will not be `nil` even if the wasi_nn plug-in is not installed, because the VM context will mock and register the host modules.
wasinnmodule := vm.GetRegisteredModule("wasi_ephemeral_nn")

vm.Release()
```

Host Module Registrations

Host functions are functions outside WebAssembly and passed to WASM modules as imports. In WasmEdge-go, the host functions are composed into host modules as Module objects with module names. Please refer to the Host Functions in WasmEdge Runtime for the details. In this chapter, we show the example for registering the host modules into a VM object.

vm := wasmedge.NewVM()
// You can also create and register the WASI host modules by this API.
wasiobj := wasmedge.NewWasiModule(/* ... ignored ... */)

res := vm.RegisterModule(wasiobj)
// The result status should be checked.

vm.Release()
// The created import objects should be released.
wasiobj.Release()

WASM Registrations And Executions

In WebAssembly, the instances in WASM modules can be exported and can be imported by other WASM modules. WasmEdge VM provides APIs for developers to register and export any WASM modules, and execute the functions or host functions in the registered WASM modules.

Unless the import objects have already contained the module names, every WASM module should be named uniquely when registering. The following shows the example.

Create a new Go project first:

mkdir wasmedge_test && cd wasmedge_test
go mod init wasmedge_test

Assume that the WASM file fibonacci.wasm from the text format fibonacci.wat is copied into the current directory. Then create and edit the Go file main.go as following:

package main

import "github.com/second-state/WasmEdge-go/wasmedge"

func main() {
  // Create VM.
  vm := wasmedge.NewVM()

  var err error
  err = vm.RegisterWasmFile("module_name", "fibonacci.wasm")
  // Developers can register the WASM module from `[]byte` with the
  // `(*VM).RegisterWasmBuffer` function, or from `AST` object with
  // the `(*VM).RegisterAST` function.
  // The result status should be checked. The error will occur if the
  // WASM module instantiation failed or the module name conflicts.

  vm.Release()
}

Execute the functions in registered WASM modules

Edit the Go file main.go as following:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  // Create VM.
  vm := wasmedge.NewVM()

  var res []interface{}
  var err error
  // Register the WASM module from file into VM with the module name "mod".
  err = vm.RegisterWasmFile("mod", "fibonacci.wasm")
  // Developers can register the WASM module from `[]byte` with the
  // `(*VM).RegisterWasmBuffer` function, or from `AST` object with
  // the `(*VM).RegisterAST` function.
  if err != nil {
    fmt.Println("WASM registration failed:", err.Error())
    return
  }
  // The function "fib" in the "fibonacci.wasm" was exported with the module
  // name "mod". As the same as host functions, other modules can import the
  // function `"mod" "fib"`.

  // Execute WASM functions in registered modules.
  // Unlike the execution of functions, the registered functions can be
  // invoked without `(*VM).Instantiate` because the WASM module was
  // instantiated when registering.
  // Developers can also invoke the host functions directly with this API.
  res, err = vm.ExecuteRegistered("mod", "fib", int32(25))
  if err == nil {
    fmt.Println("Get fibonacci[25]:", res[0].(int32))
  } else {
    fmt.Println("Run failed:", err.Error())
  }

  vm.Release()
}

Then you can build and run: (the 25th Fibonacci number is 121393 in 0-based index)

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
Get fibonacci[25]: 121393

Asynchronous Execution

Asynchronously run WASM functions rapidly

Assume that a new Go project is created as following:

mkdir wasmedge_test && cd wasmedge_test
go mod init wasmedge_test

Then assume that the WASM file fibonacci.wasm from the text format fibonacci.wat is copied into the current directory, and create and edit a Go file main.go:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  // Create VM.
  vm := wasmedge.NewVM()

  // Asynchronously run the WASM function from file and get the `wasmedge.Async` object.
  async := vm.AsyncRunWasmFile("fibonacci.wasm", "fib", uint32(20))

  // Block and wait for the execution and get the results.
  res, err := async.GetResult()
  if err == nil {
    fmt.Println("Get the result:", res[0].(int32))
  } else {
    fmt.Println("Error message:", err.Error())
  }
  async.Release()
  vm.Release()
}

Then you can build and run: (the 20th Fibonacci number is 10946 in 0-based index)

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
Get the result: 10946

Instantiate and asynchronously run WASM functions manually

Besides the above example, developers can run the WASM functions step-by-step with VM context APIs:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  var err error
  var res []interface{}

  // Create VM.
  vm := wasmedge.NewVM()

  // Step 1: Load WASM file.
  // Developers can load the WASM binary from buffer with the `(*VM).LoadWasmBuffer()` API,
  // or from `wasmedge.AST` object with the `(*VM).LoadWasmAST()` API.
  err := vm.LoadWasmFile("fibonacci.wasm")
  if err != nil {
    fmt.Println("Load WASM from file FAILED:", err.Error())
    return
  }

  // Step 2: Validate the WASM module.
  err = vm.Validate()
  if err != nil {
    fmt.Println("Validation FAILED:", err.Error())
    return
  }

  // Step 3: Instantiate the WASM module.
  err = vm.Instantiate()
  if err != nil {
    fmt.Println("Instantiation FAILED:", err.Error())
    return
  }

  // Step 4: Asynchronously execute the WASM function and get the `wasmedge.Async` object.
  async := vm.AsyncExecute("fib", uint32(25))

  // Block and wait for the execution and get the results.
  res, err := async.GetResult()
  if err == nil {
    fmt.Println("Get the result:", res[0].(int32))
  } else {
    fmt.Println("Error message:", err.Error())
  }
  async.Release()
  vm.Release()
}

Then you can build and run: (the 25th Fibonacci number is 121393 in 0-based index)

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
Get the result: 121393

Instance Tracing

Sometimes the developers may have requirements to get the instances of the WASM runtime. The VM object supplies the APIs to retrieve the instances.

Store

If the VM object is created without assigning a Store object, the VM context will allocate and own a Store.

vm := wasmedge.NewVM()
store := vm.GetStore()
// The object should __NOT__ be deleted by calling `(*Store).Release`.
vm.Release()

Developers can also create the VM object with a Store object. In this case, developers should guarantee that the Store object cannot be released before the VM object. Please refer to the Store Objects for the details about the Store APIs.

store := wasmedge.NewStore()
vm := wasmedge.NewVMWithStore(store)

storemock := vm.GetStore()
// The internal store context of the `store` and the `storemock` are the same.

vm.Release()
store.Release()

List exported functions

After the WASM module instantiation, developers can use the (*VM).Execute function to invoke the exported WASM functions. For this purpose, developers may need information about the exported WASM function list. Please refer to the Instances in runtime for the details about the function types.

Assume that a new Go project is created as following:

mkdir wasmedge_test && cd wasmedge_test
go mod init wasmedge_test

Then assume that the WASM file fibonacci.wasm from the text format fibonacci.wat is copied into the current directory, and create and edit a Go file main.go:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  // Create VM.
  vm := wasmedge.NewVM()

  // Step 1: Load WASM file.
  err := vm.LoadWasmFile("fibonacci.wasm")
  if err != nil {
    fmt.Println("Load WASM from file FAILED:", err.Error())
    return
  }

  // Step 2: Validate the WASM module.
  err = vm.Validate()
  if err != nil {
    fmt.Println("Validation FAILED:", err.Error())
    return
  }

  // Step 3: Instantiate the WASM module.
  err = vm.Instantiate()
  if err != nil {
    fmt.Println("Instantiation FAILED:", err.Error())
    return
  }

  // List the exported functions for the names and function types.
  funcnames, functypes := vm.GetFunctionList()
  for _, fname := range funcnames {
    fmt.Println("Exported function name:", fname)
  }
  for _, ftype := range functypes {
    // `ftype` is the `FunctionType` object of the same index in the `funcnames` array.
    // Developers should __NOT__ call the `ftype.Release()`.
  }

  vm.Release()
}

Then you can build and run: (the only exported function in fibonacci.wasm is fib)

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
Exported function name: fib

If developers want to get the exported function names in the registered WASM modules, please retrieve the Store object from the VM object and refer to the APIs of Store Contexts to list the registered functions by the module name.

Get function types

The VM object provides APIs to find the function type by function name. Please refer to the Instances in runtime for the details about the function types.

// Assume that a WASM module is instantiated in `vm` which is a `wasmedge.VM` object.
functype := vm.GetFunctionType("fib")
// Developers can get the function types of functions in the registered modules via the
// `(*VM).GetFunctionTypeRegistered` API with the function name and the module name.
// If the function is not found, these APIs will return `nil`.
// Developers should __NOT__ call the `(*FunctionType).Release` function of the returned object.

Get the active module
After the WASM module instantiation, an anonymous module is instantiated and owned by the VM object. Developers may need to retrieve it to get the instances beyond the module. Then developers can use the (*VM).GetActiveModule() API to get that anonymous module instance. Please refer to the Module instance for the details about the module instance APIs.
```
// Assume that a WASM module is instantiated in `vm` which is a `wasmedge.VM` object.
mod := vm.GetActiveModule()
// If there's no WASM module instantiated, this API will return `nil`.
// Developers should __NOT__ call the `(*Module).Release` function of the returned module instance.
```

List and get the registered modules

To list and retrieve the registered modules in the VM object, besides accessing the store object of the VM, developers can use the following APIs.

// Assume that the `vm` is the created `wasmedge.VM` object.
modnames := vm.ListRegisteredModule()
for _, name := range modnames {
  fmt.Println("Registered module name: ", name)
}

Get the components

The VM object is composed by the Loader, Validator, and Executor objects. For the developers who want to use these objects without creating another instances, these APIs can help developers to get them from the VM object. The get objects are owned by the VM object, and developers should not call their release functions.

loader := vm.GetLoader()
// Developers should __NOT__ call the `(*Loader).Release` function of the returned object.
validator := vm.GetValidator()
// Developers should __NOT__ call the `(*Validator).Release` function of the returned object.
executor := vm.GetExecutor()
// Developers should __NOT__ call the `(*Executor).Release` function of the returned object.

WasmEdge Runtime

In this partition, we will introduce the objects of WasmEdge runtime manually.

WASM Execution Example Step-By-Step

Besides the WASM execution through the VM object rapidly, developers can execute the WASM functions or instantiate WASM modules step-by-step with the Loader, Validator, Executor, and Store objects.

Assume that a new Go project is created as following:

mkdir wasmedge_test && cd wasmedge_test
go mod init wasmedge_test

Then assume that the WASM file fibonacci.wasm from the text format fibonacci.wat is copied into the current directory, and create and edit a Go file main.go:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  // Set the logging level to debug to print the statistics info.
  wasmedge.SetLogDebugLevel()
  // Create the configure object. This is not necessary if developers use the default configuration.
  conf := wasmedge.NewConfigure()
  // Turn on the runtime instruction counting and time measuring.
  conf.SetStatisticsInstructionCounting(true)
  conf.SetStatisticsTimeMeasuring(true)
  // Create the statistics object. This is not necessary if the statistics in runtime is not needed.
  stat := wasmedge.NewStatistics()
  // Create the store object. The store object is the WASM runtime structure core.
  store := wasmedge.NewStore()

  var err error
  var res []interface{}
  var ast *wasmedge.AST
  var mod *wasmedge.Module

  // Create the loader object.
  // For loader creation with default configuration, you can use `wasmedge.NewLoader()` instead.
  loader := wasmedge.NewLoaderWithConfig(conf)
  // Create the validator object.
  // For validator creation with default configuration, you can use `wasmedge.NewValidator()` instead.
  validator := wasmedge.NewValidatorWithConfig(conf)
  // Create the executor object.
  // For executor creation with default configuration and without statistics, you can use `wasmedge.NewExecutor()` instead.
  executor := wasmedge.NewExecutorWithConfigAndStatistics(conf, stat)

  // Load the WASM file or the compiled-WASM file and convert into the AST module object.
  ast, err = loader.LoadFile("fibonacci.wasm")
  if err != nil {
    fmt.Println("Load WASM from file FAILED:", err.Error())
    return
  }
  // Validate the WASM module.
  err = validator.Validate(ast)
  if err != nil {
    fmt.Println("Validation FAILED:", err.Error())
    return
  }
  // Instantiate the WASM module and get the output module instance.
  mod, err = executor.Instantiate(store, ast)
  if err != nil {
    fmt.Println("Instantiation FAILED:", err.Error())
    return
  }

  // Try to list the exported functions of the instantiated WASM module.
  funcnames := mod.ListFunction()
  for _, fname := range funcnames {
    fmt.Println("Exported function name:", fname)
  }

  // Invoke the WASM function.
  funcinst := mod.FindFunction("fib")
  if funcinst == nil {
    fmt.Println("Run FAILED: Function name `fib` not found")
    return
  }
  res, err = executor.Invoke(funcinst, int32(30))
  if err == nil {
    fmt.Println("Get fibonacci[30]:", res[0].(int32))
  } else {
    fmt.Println("Run FAILED:", err.Error())
  }

  // Resources deallocations.
  conf.Release()
  stat.Release()
  ast.Release()
  loader.Release()
  validator.Release()
  executor.Release()
  store.Release()
  mod.Release()
}

Then you can build and run: (the 18th Fibonacci number is 1346269 in 30-based index)

$ go get github.com/second-state/WasmEdge-go/wasmedge@v0.13.4
$ go build
$ ./wasmedge_test
Exported function name: fib
[2021-11-24 18:53:01.451] [debug]  Execution succeeded.
[2021-11-24 18:53:01.452] [debug]
 ====================  Statistics  ====================
 Total execution time: 556372295 ns
 Wasm instructions execution time: 556372295 ns
 Host functions execution time: 0 ns
 Executed wasm instructions count: 28271634
 Gas costs: 0
 Instructions per second: 50814237
Get fibonacci[30]: 1346269

Loader

The Loader object loads the WASM binary from files or buffers. Both the WASM and the compiled-WASM from the WasmEdge AOT Compiler are supported.

var buf []byte
// ... Read the WASM code to the `buf`.

// Developers can adjust settings in the configure object.
conf := wasmedge.NewConfigure()
// Create the loader object.
// For loader creation with default configuration, you can use `wasmedge.NewLoader()` instead.
loader := wasmedge.NewLoaderWithConfig(conf)
conf.Release()

// Load WASM or compiled-WASM from the file.
ast, err := loader.LoadFile("fibonacci.wasm")
if err != nil {
  fmt.Println("Load WASM from file FAILED:", err.Error())
} else {
  // The output AST object should be released.
  ast.Release()
}

// Load WASM or compiled-WASM from the buffer
ast, err = loader.LoadBuffer(buf)
if err != nil {
  fmt.Println("Load WASM from buffer FAILED:", err.Error())
} else {
  // The output AST object should be released.
  ast.Release()
}

loader.Release()

Validator

The Validator object can validate the WASM module. Every WASM module should be validated before instantiation.

// ...
// Assume that the `ast` is the output `*wasmedge.AST` object from the loader context.
// Assume that the `conf` is the `*wasmedge.Configure` object.

// Create the validator context.
// For validator creation with default configuration, you can use `wasmedge.NewValidator()` instead.
validator := wasmedge.NewValidatorWithConfig(conf)

err := validator.Validate(ast)
if err != nil {
  fmt.Println("Validation FAILED:", err.Error())
}

validator.Release()

Executor

The Executor object is the executor for both WASM and compiled-WASM. This object should work base on the Store object. For the details of the Store object, please refer to the next chapter.

Instantiate and register an AST object as a named Module instance

As the same of registering host modules or importing WASM modules in VM objects, developers can instantiate an AST module object into a named Module instance, and register it into the Store object. After the registration, the result Module instance is exported to the Store with the given module name and can be linked when instantiating another module.

For the details about the Module instances APIs, please refer to the Instances. The Store context is only the linker for searching and linking the exported modules when instantiation. Developers should release the output Module instance when it will no longer be used. When the Module instance being released, it will automatically unlink to all linked Store objects.

// ...
// Assume that the `ast` is the output `*wasmedge.AST` object from the loader
// and has passed the validation.
// Assume that the `conf` is the `*wasmedge.Configure` object.

// Create the statistics object. This step is not necessary if the statistics
// is not needed.
stat := wasmedge.NewStatistics()
// Create the executor object.
// For executor creation with default configuration and without statistics,
// you can use `wasmedge.NewExecutor()` instead.
executor := wasmedge.NewExecutorWithConfigAndStatistics(conf, stat)
// Create the store object. The store is the WASM runtime structure core.
store := wasmedge.NewStore()

// Register the loaded WASM `ast` into store with the export module name "mod".
mod, res := executor.Register(store, ast, "mod")
if err != nil {
  fmt.Println("WASM registration FAILED:", err.Error())
  return
}

// ...

// Resources deallocations.
executor.Release()
stat.Release()
store.Release()
mod.Release()

Besides instantiating and registering an AST object, developers can register an existing Module instance into the store with exporting the module name (which is in the Module instance already). This case occurs when developers create a Module instance for the host functions and want to register it for linking. For the details about the construction of host functions in Module instances, please refer to the Host Functions.

// ...
// Assume that the `ast` is the output `*wasmedge.AST` object from the loader
// and has passed the validation.
// Assume that the `conf` is the `*wasmedge.Configure` object.

// Create the statistics object. This step is not necessary if the statistics
// is not needed.
stat := wasmedge.NewStatistics()
// Create the executor object.
// For executor creation with default configuration and without statistics,
// you can use `wasmedge.NewExecutor()` instead.
executor := wasmedge.NewExecutorWithConfigAndStatistics(conf, stat)
// Create the store object. The store is the WASM runtime structure core.
store := wasmedge.NewStore()

// Create a module instance for host functions.
mod := wasmedge.NewModule("mod")
// ...
// Create and add the host functions, tables, memories, and globals into the module instance.
// ...

// Register the module instance into store with the exported module name.
// The export module name is in the module instance already.
res := executor.RegisterImport(store, mod)
if err != nil {
  fmt.Println("WASM registration FAILED:", err.Error())
  return
}

// ...

// Resources deallocations.
executor.Release()
stat.Release()
store.Release()
mod.Release()

Instantiate an AST object to an anonymous Module instance

WASM or compiled-WASM modules should be instantiated before the function invocation. Before instantiating a WASM module, please check the import section for ensuring the imports are registered into the Store object for linking.

// ...
// Assume that the `ast` is the output `*wasmedge.AST` object from the loader
// and has passed the validation.
// Assume that the `conf` is the `*wasmedge.Configure` object.

// Create the statistics object. This step is not necessary if the statistics
// is not needed.
stat := wasmedge.NewStatistics()
// Create the executor object.
// For executor creation with default configuration and without statistics,
// you can use `wasmedge.NewExecutor()` instead.
executor := wasmedge.NewExecutorWithConfigAndStatistics(conf, stat)
// Create the store object. The store is the WASM runtime structure core.
store := wasmedge.NewStore()

// Instantiate the WASM module.
mod, err := executor.Instantiate(stpre, ast)
if err != nil {
  fmt.Println("WASM instantiation FAILED:", err.Error())
  return
}

executor.Release()
stat.Release()
store.Release()
mod.Release()

Invoke functions
After registering or instantiating and get the result Module instance, developers can retrieve the exported Function instances from the Module instance for invocation. For the details about the Module instances APIs, please refer to the Instances. Please refer to the example above for the Function instance invocation with the (*Executor).Invoke API.
Asynchronously invoke functions
Such as executing WASM functions in VM asynchronously, developers can also invoke a function asynchronously by Executor objects API.
After getting the Function instance, developers will get the wasmedge.Async object by calling the (*wasmedge.executor).AsyncInvoke() API. Please refer to the Async chapter to work with this object for getting the results.

AST Module

The AST object presents the loaded structure from a WASM file or buffer. Developer will get this object after loading a WASM file or buffer from Loader. Before instantiation, developers can also query the imports and exports of an AST object.

ast := ...
// Assume that a WASM is loaded into an `*wasmedge.AST` object from loader.

// List the imports.
imports := ast.ListImports()
for _, import := range imports {
  fmt.Println("Import:", import.GetModuleName(), import.GetExternalName())
}

// List the exports.
exports := ast.ListExports()
for _, export := range exports {
  fmt.Println("Export:", export.GetExternalName())
}

ast.Release()

Store

Store is the runtime structure for the representation of all global state that can be manipulated by WebAssembly programs. The Store object in WasmEdge-Go is an object which present the linker to provide the instance exporting and importing when instantiating WASM modules. Developers can retrieve the named modules from the Store object, and should release the Module instances registered into the Store object if they will not be used anymore.

When the Store object being released, the linked Module instances will automatically unlink to this Store object. When a Module instance being released, it will automatically unlink to all the linked Store objects.

store := wasmedge.NewStore()

// ...
// Register a WASM module via the executor object.
// ...

// Try to list the registered WASM modules.
modnames := store.ListModule()
// ...

// Find named module by name.
mod := store.FindModule("module")
// If the module with name not found, the `mod` will be `nil`.

store.Release()

Instances

The instances are the runtime structures of WASM. Developers can retrieve the Module instances from the Store contexts, and retrieve the other instances from the Module instances. A single instance can be allocated by its creation function. Developers can construct instances into an Module instance for registration. Please refer to the Host Functions for details. The instances created by their creation functions should be destroyed by developers, EXCEPT they are added into an Module instance.

Module instance

After instantiating or registering an AST object, developers will get a Module instance as the result, and have the responsibility to release it when not in use. A Module instance can also be created for the host module. Please refer to the host function for the details. Module instance provides APIs to list and find the exported instances in the module.

// ...
// Instantiate a WASM module via the executor object and get the `mod` as the output module instance.
// ...

// List the exported instance of the instantiated WASM module.
// Take the function instances for example here.
funcnames := mod.ListFunction()

// Try to find the exported instance of the instantiated WASM module.
// Take the function instances for example here.
funcinst := mod.FindFunction("fib")
// `funcinst` will be `nil` if the function not found.
// The returned instance is owned by the module instance and should __NOT__ be released.

Function instance
Host functions are functions outside WebAssembly and passed to WASM modules as imports. In WasmEdge, developers can create the Function objects for host functions and add them into an Module instance for registering into a VM or a Store. Developers can retrieve the Function Type from the Function objects through the API. For the details of the Host Function guide, please refer to the next chapter.
```
funcobj := ...
// `funcobj` is the `*wasmedge.Function` retrieved from the module instance.
functype := funcobj.GetFunctionType()
// The `funcobj` retrieved from the module instance should __NOT__ be released.
// The `functype` retrieved from the `funcobj` should __NOT__ be released.

// For the function object creation, please refer to the `Host Function` guide.
```

Table instance

In WasmEdge, developers can create the Table objects and add them into an wasmedge.Module object for registering into a VM or a Store. The Table objects supply APIs to control the data in table instances.

lim := wasmedge.NewLimitWithMax(10, 20)
// Create the table type with limit and the `FuncRef` element type.
tabtype := wasmedge.NewTableType(wasmedge.RefType_FuncRef, lim)
// Create the table instance with table type.
tabinst := wasmedge.NewTable(tabtype)
// Delete the table type.
tabtype.Release()

gottabtype := tabinst.GetTableType()
// The `gottabtype` got from table instance is owned by the `tabinst`
// and should __NOT__ be released.
reftype := gottabtype.GetRefType()
// The `reftype` will be `wasmedge.RefType_FuncRef`.

var gotdata interface{}
data := wasmedge.NewFuncRef(5)
err := tabinst.SetData(data, 3)
// Set the function index 5 to the table[3].

// The following line will get an "out of bounds table access" error
// because the position (13) is out of the table size (10):
//   err = tabinst.SetData(data, 13)

gotdata, err = tabinst.GetData(3)
// Get the FuncRef value of the table[3].

// The following line will get an "out of bounds table access" error
// because the position (13) is out of the table size (10):
//   gotdata, err = tabinst.GetData(13)

tabsize := tabinst.GetSize()
// `tabsize` will be 10.
err = tabinst.Grow(6)
// Grow the table size of 6, the table size will be 16.

// The following line will get an "out of bounds table access" error
// because the size (16 + 6) will reach the table limit (20):
//   err = tabinst.Grow(6)

tabinst.Release()

Memory instance

In WasmEdge, developers can create the Memory objects and add them into an wasmedge.Module object for registering into a VM or a Store. The Memory objects supply APIs to control the data in memory instances.

lim := wasmedge.NewLimitWithMax(1, 5)
// Create the memory type with limit. The memory page size is 64KiB.
memtype := wasmedge.NewMemoryType(lim)
// Create the memory instance with memory type.
meminst := wasmedge.NewMemory(memtype)
// Delete the memory type.
memtype.Release()

data := []byte("A quick brown fox jumps over the lazy dog")
err := meminst.SetData(data, 0x1000, 10)
// Set the data[0:9] to the memory[4096:4105].

// The following line will get an "out of bounds memory access" error
// because [65535:65544] is out of 1 page size (65536):
//   err = meminst.SetData(data, 0xFFFF, 10)

var gotdata []byte
gotdata, err = meminst.GetData(0x1000, 10)
// Get the memory[4096:4105]. The `gotdata` will be `[]byte("A quick br").
// The following line will get an "out of bounds memory access" error
// because [65535:65544] is out of 1 page size (65536):
//   gotdata, err = meminst.Getdata(0xFFFF, 10)

pagesize := meminst.GetPageSize()
// `pagesize` will be 1.
err = meminst.GrowPage(2)
// Grow the page size of 2, the page size of the memory instance will be 3.

// The following line will get an "out of bounds memory access" error
// because the size (3 + 3) will reach the memory limit (5):
//   err = meminst.GetPageSize(3)

meminst.Release()

Global instance

In WasmEdge, developers can create the Global objects and add them into an wasmedge.Module object for registering into a VM or a Store. The Global objects supply APIs to control the value in global instances.

// Create the global type with value type and mutation.
globtype := wasmedge.NewGlobalType(wasmedge.ValType_I64, wasmedge.ValMut_Var)
// Create the global instance with value and global type.
globinst := wasmedge.NewGlobal(globtype, uint64(1000))
// Delete the global type.
globtype.Release()

gotglobtype := globinst.GetGlobalType()
// The `gotglobtype` got from global instance is owned by the `globinst`
// and should __NOT__ be released.
valtype := gotglobtype.GetValType()
// The `valtype` will be `wasmedge.ValType_I64`.
valmut := gotglobtype.GetMutability()
// The `valmut` will be `wasmedge.ValMut_Var`.

globinst.SetValue(uint64(888))
// Set the value u64(888) to the global.
// This function will do nothing if the value type mismatched or the
// global mutability is `wasmedge.ValMut_Const`.
gotval := globinst.GetValue()
// The `gotbal` will be `interface{}` which the type is `uint64` and
// the value is 888.

globinst.Release()

Host Functions

Host functions are functions outside WebAssembly and passed to WASM modules as imports. In WasmEdge, the host functions are composed into host modules as wasmedge.Module objects with module names. Please refer to the Host Functions in WasmEdge Runtime for the details.

In this chapter, we show the example for registering the host modules into a VM object. Noticed that the developers should guarantee the availability of the registered module instances, and should release the module instances when they will not be used.

Host function allocation

Developers can define Go functions with the following function signature as the host function body:

type hostFunctionSignature func(
    data interface{}, callframe *CallingFrame, params []interface{}) ([]interface{}, Result)

The example of an add host function to add 2 i32 values:

func host_add(data interface{}, callframe *wasmedge.CallingFrame, params []interface{}) ([]interface{}, wasmedge.Result) {
  // add: i32, i32 -> i32
  res := params[0].(int32) + params[1].(int32)

  // Set the returns
  returns := make([]interface{}, 1)
  returns[0] = res

  // Return
  return returns, wasmedge.Result_Success
}

Then developers can create Function object with the host function body and function type:

// Create a function type: {i32, i32} -> {i32}.
functype := wasmedge.NewFunctionType(
  []wasmedge.ValType{wasmedge.ValType_I32, wasmedge.ValType_I32},
  []wasmedge.ValType{wasmedge.ValType_I32},
)

// Create a function context with the function type and host function body.
// The third parameter is the pointer to the additional data.
// Developers should guarantee the life cycle of the data, and it can be
// `nil` if the external data is not needed.
// The last parameter can be 0 if developers do not need the cost measuring.
func_add := wasmedge.NewFunction(functype, host_add, nil, 0)

// If the function object is not added into an module instance object, it should be released.
func_add.Release()
functype.Release()

Calling frame object
The wasmedge.CallingFrame is the object to provide developers to access the module instance of the frame on the top of the calling stack. According to the WASM spec, a frame with the module instance is pushed into the stack when invoking a function. Therefore, the host functions can access the module instance of the top frame to retrieve the memory instances to read/write data.
```
import (
  "encoding/binary"
  "fmt"
)

// Host function body definition.
func LoadOffset(data interface{}, callframe *wasmedge.CallingFrame, params []interface{}) ([]interface{}, wasmedge.Result) {
  // Function type: {i32} -> {}
  offset := params[0].(int32)

  // Get the 0th memory instance of the module of the top frame on the stack.
  mem := callframe.GetMemoryByIndex(0)

  data, err := mem.GetData(uint(offset), 4)
  if err != nil {
    return nil, err
  }
  fmt.Println("u32 at memory[{}]: {}", offset, binary.LittleEndian.Uint32(data))
  return nil, wasmedge.Result_Success
}
```
Besides using the (*CallingFrame).GetMemoryByIndex() API to get the memory instance by index in the module instance, developers can use the (*CallingFrame).GetModule() to get the module instance directly. Therefore, developers can retrieve the exported contexts by the wasmedge.Module APIs. And also, developers can use the (*CallingFrame).GetExecutor() API to get the currently used executor context.

User-defined error code of the host functions

In host functions, WasmEdge-Go provides wasmedge.Result_Success to return success, wasmedge.Result_Terminate to terminate the WASM execution, and wasmedge.Result_Fail to return fail. WasmEdge-Go also provides the usage of returning the user-specified codes. Developers can use the wasmedge.NewResult() API to generate the wasmedge.Result struct with error code, and use the (*result).GetCode() API to get the error code.

Notice: The error code only supports 24-bit integer (0 ~ 16777216 in uint32). The values larger than 24-bit will be truncated.

Create a new Go project first:

mkdir wasmedge_test && cd wasmedge_test
go mod init wasmedge_test

Assume that a simple WASM from the WAT is as following:

(module
  (type $t0 (func (param i32)))
  (import "extern" "trap" (func $f-trap (type $t0)))
  (func (export "trap") (param i32)
    local.get 0
    call $f-trap)
)

And the main.go is as following:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

// Host function body definition.
func host_trap(data interface{}, callframe *wasmedge.CallingFrame, params []interface{}) ([]interface{}, wasmedge.Result) {
  // add: i32, i32 -> i32
  res := params[0].(int32) + params[1].(int32)

  // Set the returns
  returns := make([]interface{}, 1)
  returns[0] = res

  // Return
  return returns, wasmedge.Result_Success
}

func main() {
  // Create the VM object.
  vm := wasmedge.NewVM()

  // The WASM module buffer.
  wasmbuf := []byte{
    /* WASM header */
    0x00, 0x61, 0x73, 0x6D, 0x01, 0x00, 0x00, 0x00,
    /* Type section */
    0x01, 0x05, 0x01,
    /* function type {i32} -> {} */
    0x60, 0x01, 0x7F, 0x00,
    /* Import section */
    0x02, 0x0F, 0x01,
    /* module name: "extern" */
    0x06, 0x65, 0x78, 0x74, 0x65, 0x72, 0x6E,
    /* extern name: "trap" */
    0x04, 0x74, 0x72, 0x61, 0x70,
    /* import desc: func 0 */
    0x00, 0x00,
    /* Function section */
    0x03, 0x02, 0x01, 0x00,
    /* Export section */
    0x07, 0x08, 0x01,
    /* export name: "trap" */
    0x04, 0x74, 0x72, 0x61, 0x70,
    /* export desc: func 0 */
    0x00, 0x01,
    /* Code section */
    0x0A, 0x08, 0x01,
    /* code body */
    0x06, 0x00, 0x20, 0x00, 0x10, 0x00, 0x0B,
  }

  // Create the module instance with the module name "extern".
  impmod := wasmedge.NewModule("extern")

  // Create and add a function instance into the module instance with export name "func-add".
  functype := wasmedge.NewFunctionType([]wasmedge.ValType{wasmedge.ValType_I32}, []wasmedge.ValType{})
  hostfunc := wasmedge.NewFunction(functype, host_trap, nil, 0)
  functype.Release()
  impmod.AddFunction("trap", hostfunc)

  // Register the module instance into VM.
  vm.RegisterImport(impmod)

  _, err := vm.RunWasmBuffer(wasmbuf, "trap", uint32(5566))
  if err != nil {
    fmt.Println("Get the error code:", err.GetCode())
  }

  impmod.Release()
  vm.Release()
}

Then you can build and run the Golang application with the WasmEdge Golang SDK:

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
[2022-08-26 15:06:40.384] [error] user defined failed: user defined error code, Code: 0x15be
[2022-08-26 15:06:40.384] [error]     When executing function name: "trap"
Get the error code: 5566

Construct a module instance with host instances

Besides creating a Module instance by registering or instantiating a WASM module, developers can create a Module instance with a module name and add the Function, Memory, Table, and Global instances into it with their exporting names.

// Host function body definition.
func host_add(data interface{}, callframe *wasmedge.CallingFrame, params []interface{}) ([]interface{}, wasmedge.Result) {
  // add: i32, i32 -> i32
  res := params[0].(int32) + params[1].(int32)

  // Set the returns
  returns := make([]interface{}, 1)
  returns[0] = res

  // Return
  return returns, wasmedge.Result_Success
}

// Create a module instance with the module name "module".
mod := wasmedge.NewModule("module")

// Create and add a function instance into the module instance with export name "add".
functype := wasmedge.NewFunctionType(
  []wasmedge.ValType{wasmedge.ValType_I32, wasmedge.ValType_I32},
  []wasmedge.ValType{wasmedge.ValType_I32},
)
hostfunc := wasmedge.NewFunction(functype, host_add, nil, 0)
functype.Release()
mod.AddFunction("add", hostfunc)

// Create and add a table instance into the module instance with export name "table".
tabtype := wasmedge.NewTableType(wasmedge.RefType_FuncRef ,wasmedge.NewLimitWithMax(10, 20))
hosttab := wasmedge.NewTable(tabtype)
tabtype.Release()
mod.AddTable("table", hosttab)

// Create and add a memory instance into the module instance with export name "memory".
memtype := wasmedge.NewMemoryType(wasmedge.NewLimitWithMax(1, 2))
hostmem := wasmedge.NewMemory(memtype)
memtype.Release()
mod.AddMemory("memory", hostmem)

// Create and add a global instance into the module instance with export name "global".
globtype := wasmedge.NewGlobalType(wasmedge.ValType_I32, wasmedge.ValMut_Var)
hostglob := wasmedge.NewGlobal(globtype, uint32(666))
globtype.Release()
mod.AddGlobal("global", hostglob)

// The module instances should be released.
// Developers should __NOT__ release the instances added into the module instance objects.
mod.Release()

Specified module instance

wasmedge.NewWasiModule() API can create and initialize the WASI module instance.

wasiobj := wasmedge.NewWasiModule(
  os.Args[1:],     // The args
  os.Environ(),    // The envs
  []string{".:."}, // The mapping preopens
)

// Register the WASI into the VM object.
vm := wasmedge.NewVM()
vm.RegisterImport(wasiobj)

// ... Execute some WASM functions.

// Get the WASI exit code.
exitcode := wasiobj.WasiGetExitCode()
// The `exitcode` will be 0 if the WASI function "_start" execution has no error.
// Otherwise, it will return with the related exit code.

vm.Release()
// The import objects should be deleted.
wasiobj.Release()

Example

Assume that there is a simple WASM from the WAT as following:

(module
  (type $t0 (func (param i32 i32) (result i32)))
  (import "extern" "func-add" (func $f-add (type $t0)))
  (func (export "addTwo") (param i32 i32) (result i32)
    local.get 0
    local.get 1
    call $f-add)
)

Assume that edit the Go file main.go above:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

// Host function body definition.
func host_add(data interface{}, callframe *wasmedge.CallingFrame, params []interface{}) ([]interface{}, wasmedge.Result) {
  // add: i32, i32 -> i32
  res := params[0].(int32) + params[1].(int32)

  // Set the returns
  returns := make([]interface{}, 1)
  returns[0] = res

  // Return
  return returns, wasmedge.Result_Success
}

func main() {
  // Create the VM object.
  vm := wasmedge.NewVM()

  // The WASM module buffer.
  wasmbuf := []byte{
    /* 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,
  }

  // Create the module instance with the module name "extern".
  impmod := wasmedge.NewModule("extern")

  // Create and add a function instance into the module instance with export name "func-add".
  functype := wasmedge.NewFunctionType(
    []wasmedge.ValType{wasmedge.ValType_I32, wasmedge.ValType_I32},
    []wasmedge.ValType{wasmedge.ValType_I32},
  )
  hostfunc := wasmedge.NewFunction(functype, host_add, nil, 0)
  functype.Release()
  impmod.AddFunction("func-add", hostfunc)

  // Register the module instance into VM.
  vm.RegisterImport(impmod)

  res, err := vm.RunWasmBuffer(wasmbuf, "addTwo", uint32(1234), uint32(5678))
  if err == nil {
    fmt.Println("Get the result:", res[0].(int32))
  } else {
    fmt.Println("Error message:", err.Error())
  }

  impmod.Release()
  vm.Release()
}

Then you can build and run the Golang application with the WasmEdge Golang SDK:

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
Get the result: 6912

Host Data Example

Developers can set a external data object to the Function object, and access to the object in the function body. Assume that edit the Go file main.go above:

package main

import (
  "fmt"

  "github.com/second-state/WasmEdge-go/wasmedge"
)

// Host function body definition.
func host_add(data interface{}, callframe *wasmedge.CallingFrame, params []interface{}) ([]interface{}, wasmedge.Result) {
  // add: i32, i32 -> i32
  res := params[0].(int32) + params[1].(int32)

  // Set the returns
  returns := make([]interface{}, 1)
  returns[0] = res

  // Also set the result to the data.
  *data.(*int32) = res

  // Return
  return returns, wasmedge.Result_Success
}

func main() {
  // Create the VM object.
  vm := wasmedge.NewVM()

  // The WASM module buffer.
  wasmbuf := []byte{
    /* 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,
  }

  // The additional data to set into the host function.
  var data int32 = 0

  // Create the module instance with the module name "extern".
  modinst := wasmedge.NewModule("extern")

  // Create and add a function instance into the module instance with export name "func-add".
  functype := wasmedge.NewFunctionType(
    []wasmedge.ValType{wasmedge.ValType_I32, wasmedge.ValType_I32},
    []wasmedge.ValType{wasmedge.ValType_I32},
  )
  hostfunc := wasmedge.NewFunction(functype, host_add, &data, 0)
  functype.Release()
  modinst.AddFunction("func-add", hostfunc)

  // Register the module instance into VM.
  vm.RegisterImport(modinst)

  res, err := vm.RunWasmBuffer(wasmbuf, "addTwo", uint32(1234), uint32(5678))
  if err == nil {
    fmt.Println("Get the result:", res[0].(int32))
  } else {
    fmt.Println("Error message:", err.Error())
  }
  fmt.Println("Data value:", data)

  modinst.Release()
  vm.Release()
}

Then you can build and run the Golang application with the WasmEdge Golang SDK:

$ go get github.com/second-state/WasmEdge-go/wasmedge@v{{ wasmedge_go_version }}
$ go build
$ ./wasmedge_test
Get the result: 6912
Data value: 6912

Plug-ins

The WasmEdge plug-ins are the shared libraries to provide the WasmEdge runtime to load and create host module instances. With the plug-ins, the WasmEdge runtime can be extended more easily.

Load plug-ins from paths

To use the plug-ins, developers should load the plug-ins from paths first.

wasmedge.LoadPluginDefaultPaths()

After calling this API, the plug-ins in the default paths will be loaded. The default paths are:

The path given in the environment variable WASMEDGE_PLUGIN_PATH.
The ../plugin/ directory related to the WasmEdge installation path.
The ./wasmedge/ directory under the library path if the WasmEdge is installed under the system directory (such as /usr and /usr/local).

To load the plug-ins from a specific path or under a specific directory, developers can use this API:

wasmedge.LoadPluginFromPath("PATH_TO_PLUGIN/plugin.so")

Get the plug-in by name

After loading the plug-ins, developers can list the loaded plug-in names.

wasmedge.LoadPluginDefaultPaths()
pluginnames := wasmedge.ListPlugins()
for _, name := range pluginnames {
  fmt.Println("Loaded plug-in name: ", name)
}

And developers can retrieve the plug-in object by its name.

// Assume that wasi_crypto plug-in is installed in the default plug-in path.
wasmedge.LoadPluginDefaultPaths()
plugincrypto := wasmedge.FindPlugin("wasi_crypto")

Create the module instance from a plug-in

With the plug-in object, developers can create the module instances by the module name.

// Assume that the `plugincrypto` is the object to the wasi_crypto plug-in.

// List the available host modules in the plug-in.
modules := plugincrypto.ListModule()
for _, name := range modules {
  fmt.Println("Available module: ", name)
}
// Will print here for the WASI-Crypto plug-in here:
//   wasi_ephemeral_crypto_asymmetric_common
//   wasi_ephemeral_crypto_common
//   wasi_ephemeral_crypto_kx
//   wasi_ephemeral_crypto_signatures
//   wasi_ephemeral_crypto_symmetric

// Create a module instance from the plug-in by the module name.
modinst := plugincrypto.CreateModule("wasi_ephemeral_crypto_common")

modinst.Release()

WasmEdge AOT Compiler

In this partition, we will introduce the WasmEdge AOT compiler and the options in Go. WasmEdge runs the WASM files in interpreter mode, and WasmEdge also supports the AOT (ahead-of-time) mode running without modifying any code. The WasmEdge AOT (ahead-of-time) compiler compiles the WASM files for running in AOT mode which is much faster than interpreter mode. Developers can compile the WASM files into the compiled-WASM files in shared library format for universal WASM format for the AOT mode execution.

Compilation Example

The go_WasmAOT example provide a tool for compiling a WASM file.

Compiler Options

Developers can set options for AOT compilers such as optimization level and output format:

const (
  // Disable as many optimizations as possible.
  CompilerOptLevel_O0 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O0)
  // Optimize quickly without destroying debuggability.
  CompilerOptLevel_O1 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O1)
  // Optimize for fast execution as much as possible without triggering significant incremental compile time or code size growth.
  CompilerOptLevel_O2 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O2)
  // Optimize for fast execution as much as possible.
  CompilerOptLevel_O3 = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_O3)
  // Optimize for small code size as much as possible without triggering significant incremental compile time or execution time slowdowns.
  CompilerOptLevel_Os = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_Os)
  // Optimize for small code size as much as possible.
  CompilerOptLevel_Oz = CompilerOptimizationLevel(C.WasmEdge_CompilerOptimizationLevel_Oz)
)

const (
  // Native dynamic library format.
  CompilerOutputFormat_Native = CompilerOutputFormat(C.WasmEdge_CompilerOutputFormat_Native)
  // WebAssembly with AOT compiled codes in custom section.
  CompilerOutputFormat_Wasm = CompilerOutputFormat(C.WasmEdge_CompilerOutputFormat_Wasm)
)

Please refer to the AOT compiler options configuration for details.

WasmEdge CLI Tools

Besides executing the wasmedge and wasmedgec CLI tools, developers can trigger the WasmEdge CLI tools in WasmEdge-Go. The API arguments are the same as the command line arguments of the CLI tools.

Runtime CLI

The wasmedge.RunWasmEdgeCLI() API presents the same function as running the wasmedge run command.

Noticed that this API presents the old wasmedge CLI tool, which is the same as the wasmedge run command. For the current unified wasmedge CLI, please refer to the API below.

package main

import (
  "os"
  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  wasmedge.RunWasmEdgeCLI(os.Args)
}

Compiler CLI

The wasmedge.RunWasmEdgeAOTCompilerCLI() API presents the same function as running the wasmedge compile tool.

Noticed that this API presents the old wasmedgec CLI tool, which is the same as the wasmedge compile command. For the current unified wasmedge CLI, please refer to the API below.

package main

import (
  "os"
  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  wasmedge.RunWasmEdgeAOTCompilerCLI(os.Args)
}

Unified CLI

The wasmedge.RunWasmEdgeUnifiedCLI() API presents the same function as running the wasmedge tool.

package main

import (
  "os"
  "github.com/second-state/WasmEdge-go/wasmedge"
)

func main() {
  wasmedge.RunWasmEdgeUnifiedCLI(os.Args)
}

Go API v0.13.4 Documentation

Getting Started​

WasmEdge Installation​

Get WasmEdge-go​

Example Repository​

WasmEdge-go Basics​

Version​

Logging Settings​

Value Types​

Results​

Contexts And Their Life Cycles​

WASM Data Structures​

Async​

Configurations​

Statistics​

WasmEdge VM​

WASM Execution Example With VM Object​

VM Creations​

Built-in Host Modules and Plug-in Preregistrations​

Host Module Registrations​

WASM Registrations And Executions​

Asynchronous Execution​

Instance Tracing​

WasmEdge Runtime​

WASM Execution Example Step-By-Step​

Loader​

Validator​

Executor​

AST Module​

Store​

Instances​

Host Functions​

Plug-ins​

Load plug-ins from paths​

Get the plug-in by name​

Create the module instance from a plug-in​

WasmEdge AOT Compiler​

Compilation Example​

Compiler Options​

WasmEdge CLI Tools​

Runtime CLI​

Compiler CLI​

Unified CLI​

Getting Started

WasmEdge Installation

Get WasmEdge-go

Example Repository

WasmEdge-go Basics

Version

Logging Settings

Value Types

Results

Contexts And Their Life Cycles

WASM Data Structures

Async

Configurations

Statistics

WasmEdge VM

WASM Execution Example With VM Object

VM Creations

Built-in Host Modules and Plug-in Preregistrations

Host Module Registrations

WASM Registrations And Executions

Asynchronous Execution

Instance Tracing

WasmEdge Runtime

WASM Execution Example Step-By-Step

Loader

Validator

Executor

AST Module

Store

Instances

Host Functions

Plug-ins

Load plug-ins from paths

Get the plug-in by name

Create the module instance from a plug-in

WasmEdge AOT Compiler

Compilation Example

Compiler Options

WasmEdge CLI Tools

Runtime CLI

Compiler CLI

Unified CLI