100 lines
2.2 KiB
Go
100 lines
2.2 KiB
Go
// Copyright 2017 The go-interpreter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package exec
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import (
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"fmt"
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"math"
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"reflect"
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"github.com/go-interpreter/wagon/exec/internal/compile"
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)
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type function interface {
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call(vm *VM, index int64)
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}
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type compiledFunction struct {
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code []byte
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branchTables []*compile.BranchTable
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maxDepth int // maximum stack depth reached while executing the function body
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totalLocalVars int // number of local variables used by the function
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args int // number of arguments the function accepts
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returns bool // whether the function returns a value
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}
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type goFunction struct {
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val reflect.Value
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typ reflect.Type
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}
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func (fn goFunction) call(vm *VM, index int64) {
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numIn := fn.typ.NumIn()
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args := make([]reflect.Value, numIn)
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for i := numIn - 1; i >= 0; i-- {
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val := reflect.New(fn.typ.In(i)).Elem()
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raw := vm.popUint64()
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kind := fn.typ.In(i).Kind()
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switch kind {
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case reflect.Float64, reflect.Float32:
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val.SetFloat(math.Float64frombits(raw))
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case reflect.Uint32, reflect.Uint64:
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val.SetUint(raw)
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case reflect.Int32, reflect.Int64:
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val.SetInt(int64(raw))
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default:
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panic(fmt.Sprintf("exec: args %d invalid kind=%v", i, kind))
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}
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args[i] = val
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}
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rtrns := fn.val.Call(args)
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for i, out := range rtrns {
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kind := out.Kind()
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switch kind {
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case reflect.Float64, reflect.Float32:
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vm.pushFloat64(out.Float())
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case reflect.Uint32, reflect.Uint64:
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vm.pushUint64(out.Uint())
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case reflect.Int32, reflect.Int64:
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vm.pushInt64(out.Int())
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default:
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panic(fmt.Sprintf("exec: return value %d invalid kind=%v", i, kind))
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}
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}
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}
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func (compiled compiledFunction) call(vm *VM, index int64) {
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newStack := make([]uint64, compiled.maxDepth)
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locals := make([]uint64, compiled.totalLocalVars)
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for i := compiled.args - 1; i >= 0; i-- {
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locals[i] = vm.popUint64()
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}
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//save execution context
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prevCtxt := vm.ctx
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vm.ctx = context{
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stack: newStack,
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locals: locals,
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code: compiled.code,
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pc: 0,
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curFunc: index,
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}
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rtrn := vm.execCode(compiled)
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//restore execution context
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vm.ctx = prevCtxt
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if compiled.returns {
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vm.pushUint64(rtrn)
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}
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}
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