tools/go/ssa/interp/external.go

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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package interp
// Emulated functions that we cannot interpret because they are
// external or because they use "unsafe" or "reflect" operations.
import (
"go/types"
"math"
"os"
"runtime"
"strings"
"sync/atomic"
"time"
"unsafe"
"golang.org/x/tools/go/ssa"
)
type externalFn func(fr *frame, args []value) value
// TODO(adonovan): fix: reflect.Value abstracts an lvalue or an
// rvalue; Set() causes mutations that can be observed via aliases.
// We have not captured that correctly here.
// Key strings are from Function.String().
var externals = make(map[string]externalFn)
func init() {
// That little dot ۰ is an Arabic zero numeral (U+06F0), categories [Nd].
for k, v := range map[string]externalFn{
"(*sync.Pool).Get": ext۰sync۰Pool۰Get,
"(*sync.Pool).Put": ext۰nop,
"(reflect.Value).Bool": ext۰reflect۰Value۰Bool,
"(reflect.Value).CanAddr": ext۰reflect۰Value۰CanAddr,
"(reflect.Value).CanInterface": ext۰reflect۰Value۰CanInterface,
"(reflect.Value).Elem": ext۰reflect۰Value۰Elem,
"(reflect.Value).Field": ext۰reflect۰Value۰Field,
"(reflect.Value).Float": ext۰reflect۰Value۰Float,
"(reflect.Value).Index": ext۰reflect۰Value۰Index,
"(reflect.Value).Int": ext۰reflect۰Value۰Int,
"(reflect.Value).Interface": ext۰reflect۰Value۰Interface,
"(reflect.Value).IsNil": ext۰reflect۰Value۰IsNil,
"(reflect.Value).IsValid": ext۰reflect۰Value۰IsValid,
"(reflect.Value).Kind": ext۰reflect۰Value۰Kind,
"(reflect.Value).Len": ext۰reflect۰Value۰Len,
"(reflect.Value).MapIndex": ext۰reflect۰Value۰MapIndex,
"(reflect.Value).MapKeys": ext۰reflect۰Value۰MapKeys,
"(reflect.Value).NumField": ext۰reflect۰Value۰NumField,
"(reflect.Value).NumMethod": ext۰reflect۰Value۰NumMethod,
"(reflect.Value).Pointer": ext۰reflect۰Value۰Pointer,
"(reflect.Value).Set": ext۰reflect۰Value۰Set,
"(reflect.Value).String": ext۰reflect۰Value۰String,
"(reflect.Value).Type": ext۰reflect۰Value۰Type,
"(reflect.Value).Uint": ext۰reflect۰Value۰Uint,
"(reflect.error).Error": ext۰reflect۰error۰Error,
"(reflect.rtype).Bits": ext۰reflect۰rtype۰Bits,
"(reflect.rtype).Elem": ext۰reflect۰rtype۰Elem,
"(reflect.rtype).Field": ext۰reflect۰rtype۰Field,
"(reflect.rtype).In": ext۰reflect۰rtype۰In,
"(reflect.rtype).Kind": ext۰reflect۰rtype۰Kind,
"(reflect.rtype).NumField": ext۰reflect۰rtype۰NumField,
"(reflect.rtype).NumIn": ext۰reflect۰rtype۰NumIn,
"(reflect.rtype).NumMethod": ext۰reflect۰rtype۰NumMethod,
"(reflect.rtype).NumOut": ext۰reflect۰rtype۰NumOut,
"(reflect.rtype).Out": ext۰reflect۰rtype۰Out,
"(reflect.rtype).Size": ext۰reflect۰rtype۰Size,
"(reflect.rtype).String": ext۰reflect۰rtype۰String,
"bytes.init": ext۰nop, // avoid asm dependency
"bytes.Equal": ext۰bytes۰Equal,
"bytes.IndexByte": ext۰bytes۰IndexByte,
"hash/crc32.haveSSE42": ext۰crc32۰haveSSE42,
"internal/cpu.cpuid": ext۰cpu۰cpuid,
"internal/syscall/unix.syscall_fcntl": ext۰syscall۰unix۰syscall_fcntl,
"math.Abs": ext۰math۰Abs,
"math.Exp": ext۰math۰Exp,
"math.Float32bits": ext۰math۰Float32bits,
"math.Float32frombits": ext۰math۰Float32frombits,
"math.Float64bits": ext۰math۰Float64bits,
"math.Float64frombits": ext۰math۰Float64frombits,
"math.Ldexp": ext۰math۰Ldexp,
"math.Log": ext۰math۰Log,
"math.Min": ext۰math۰Min,
"math.hasSSE4": ext۰math۰hasSSE4,
"math.hasVectorFacility": ext۰math۰hasVectorFacility,
"os.runtime_args": ext۰os۰runtime_args,
"os.runtime_beforeExit": ext۰nop,
"os/signal.init": ext۰nop,
"reflect.New": ext۰reflect۰New,
"reflect.SliceOf": ext۰reflect۰SliceOf,
"reflect.TypeOf": ext۰reflect۰TypeOf,
"reflect.ValueOf": ext۰reflect۰ValueOf,
"reflect.Zero": ext۰reflect۰Zero,
"reflect.init": ext۰reflect۰Init,
"reflect.valueInterface": ext۰reflect۰valueInterface,
"runtime.Breakpoint": ext۰runtime۰Breakpoint,
"runtime.Caller": ext۰runtime۰Caller,
"runtime.Callers": ext۰runtime۰Callers,
"runtime.FuncForPC": ext۰runtime۰FuncForPC,
"runtime.GC": ext۰runtime۰GC,
"runtime.GOMAXPROCS": ext۰runtime۰GOMAXPROCS,
"runtime.Goexit": ext۰runtime۰Goexit,
"runtime.Gosched": ext۰runtime۰Gosched,
"runtime.init": ext۰nop,
"runtime.KeepAlive": ext۰nop,
"runtime.NumCPU": ext۰runtime۰NumCPU,
"runtime.NumGoroutine": ext۰runtime۰NumGoroutine,
"runtime.ReadMemStats": ext۰runtime۰ReadMemStats,
"runtime.SetFinalizer": ext۰nop, // ignore
"(*runtime.Func).Entry": ext۰runtime۰Func۰Entry,
"(*runtime.Func).FileLine": ext۰runtime۰Func۰FileLine,
"(*runtime.Func).Name": ext۰runtime۰Func۰Name,
"runtime.environ": ext۰runtime۰environ,
"runtime.getgoroot": ext۰runtime۰getgoroot,
"strings.init": ext۰nop, // avoid asm dependency
"strings.Count": ext۰strings۰Count,
"strings.Index": ext۰strings۰Index,
"strings.IndexByte": ext۰strings۰IndexByte,
"sync.runtime_Semacquire": ext۰nop, // unimplementable
"sync.runtime_Semrelease": ext۰nop, // unimplementable
"sync.runtime_Syncsemcheck": ext۰nop, // unimplementable
"sync.runtime_notifyListCheck": ext۰nop,
"sync.runtime_registerPoolCleanup": ext۰nop,
"sync/atomic.AddInt32": ext۰atomic۰AddInt32,
"sync/atomic.AddUint32": ext۰atomic۰AddUint32,
"sync/atomic.CompareAndSwapInt32": ext۰atomic۰CompareAndSwapInt32,
"sync/atomic.CompareAndSwapUint32": ext۰atomic۰CompareAndSwapUint32,
"sync/atomic.LoadInt32": ext۰atomic۰LoadInt32,
"sync/atomic.LoadUint32": ext۰atomic۰LoadUint32,
"sync/atomic.StoreInt32": ext۰atomic۰StoreInt32,
"sync/atomic.StoreUint32": ext۰atomic۰StoreUint32,
"sync/atomic.AddInt64": ext۰atomic۰AddInt64,
"sync/atomic.AddUint64": ext۰atomic۰AddUint64,
"sync/atomic.CompareAndSwapInt64": ext۰atomic۰CompareAndSwapInt64,
"sync/atomic.CompareAndSwapUint64": ext۰atomic۰CompareAndSwapUint64,
"sync/atomic.LoadInt64": ext۰atomic۰LoadInt64,
"sync/atomic.LoadUint64": ext۰atomic۰LoadUint64,
"sync/atomic.StoreInt64": ext۰atomic۰StoreInt64,
"sync/atomic.StoreUint64": ext۰atomic۰StoreUint64,
"(*sync/atomic.Value).Load": ext۰atomic۰ValueLoad,
"(*sync/atomic.Value).Store": ext۰atomic۰ValueStore,
"testing.MainStart": ext۰testing۰MainStart,
"time.Sleep": ext۰time۰Sleep,
"time.now": ext۰time۰now,
} {
externals[k] = v
}
}
// wrapError returns an interpreted 'error' interface value for err.
func wrapError(err error) value {
if err == nil {
return iface{}
}
return iface{t: errorType, v: err.Error()}
}
func ext۰nop(fr *frame, args []value) value { return nil }
func ext۰sync۰Pool۰Get(fr *frame, args []value) value {
Pool := fr.i.prog.ImportedPackage("sync").Type("Pool").Object()
_, newIndex, _ := types.LookupFieldOrMethod(Pool.Type(), false, Pool.Pkg(), "New")
if New := (*args[0].(*value)).(structure)[newIndex[0]]; New != nil {
return call(fr.i, fr, 0, New, nil)
}
return nil
}
func ext۰bytes۰Equal(fr *frame, args []value) value {
// func Equal(a, b []byte) bool
a := args[0].([]value)
b := args[1].([]value)
if len(a) != len(b) {
return false
}
for i := range a {
if a[i] != b[i] {
return false
}
}
return true
}
func ext۰bytes۰IndexByte(fr *frame, args []value) value {
// func IndexByte(s []byte, c byte) int
s := args[0].([]value)
c := args[1].(byte)
for i, b := range s {
if b.(byte) == c {
return i
}
}
return -1
}
func ext۰crc32۰haveSSE42(fr *frame, args []value) value {
return false
}
func ext۰math۰Float64frombits(fr *frame, args []value) value {
return math.Float64frombits(args[0].(uint64))
}
func ext۰math۰Float64bits(fr *frame, args []value) value {
return math.Float64bits(args[0].(float64))
}
func ext۰math۰Float32frombits(fr *frame, args []value) value {
return math.Float32frombits(args[0].(uint32))
}
func ext۰math۰Abs(fr *frame, args []value) value {
return math.Abs(args[0].(float64))
}
func ext۰math۰Exp(fr *frame, args []value) value {
return math.Exp(args[0].(float64))
}
func ext۰math۰Float32bits(fr *frame, args []value) value {
return math.Float32bits(args[0].(float32))
}
func ext۰math۰Min(fr *frame, args []value) value {
return math.Min(args[0].(float64), args[1].(float64))
}
func ext۰math۰hasSSE4(fr *frame, args []value) value {
return false
}
func ext۰math۰hasVectorFacility(fr *frame, args []value) value {
return false
}
func ext۰math۰Ldexp(fr *frame, args []value) value {
return math.Ldexp(args[0].(float64), args[1].(int))
}
func ext۰math۰Log(fr *frame, args []value) value {
return math.Log(args[0].(float64))
}
func ext۰os۰runtime_args(fr *frame, args []value) value {
return fr.i.osArgs
}
func ext۰runtime۰Breakpoint(fr *frame, args []value) value {
runtime.Breakpoint()
return nil
}
func ext۰runtime۰Caller(fr *frame, args []value) value {
// func Caller(skip int) (pc uintptr, file string, line int, ok bool)
skip := 1 + args[0].(int)
for i := 0; i < skip; i++ {
if fr != nil {
fr = fr.caller
}
}
var pc uintptr
var file string
var line int
var ok bool
if fr != nil {
fn := fr.fn
// TODO(adonovan): use pc/posn of current instruction, not start of fn.
// (Required to interpret the log package's tests.)
pc = uintptr(unsafe.Pointer(fn))
posn := fn.Prog.Fset.Position(fn.Pos())
file = posn.Filename
line = posn.Line
ok = true
}
return tuple{pc, file, line, ok}
}
func ext۰runtime۰Callers(fr *frame, args []value) value {
// Callers(skip int, pc []uintptr) int
skip := args[0].(int)
pc := args[1].([]value)
for i := 0; i < skip; i++ {
if fr != nil {
fr = fr.caller
}
}
i := 0
for fr != nil && i < len(pc) {
pc[i] = uintptr(unsafe.Pointer(fr.fn))
i++
fr = fr.caller
}
return i
}
func ext۰runtime۰FuncForPC(fr *frame, args []value) value {
// FuncForPC(pc uintptr) *Func
pc := args[0].(uintptr)
var fn *ssa.Function
if pc != 0 {
fn = (*ssa.Function)(unsafe.Pointer(pc)) // indeed unsafe!
}
var Func value
Func = structure{fn} // a runtime.Func
return &Func
}
func ext۰runtime۰environ(fr *frame, args []value) value {
// This function also implements syscall.runtime_envs.
return environ
}
func ext۰runtime۰getgoroot(fr *frame, args []value) value {
return os.Getenv("GOROOT")
}
func ext۰strings۰Count(fr *frame, args []value) value {
// Call compiled version to avoid asm dependency.
return strings.Count(args[0].(string), args[1].(string))
}
func ext۰strings۰IndexByte(fr *frame, args []value) value {
// Call compiled version to avoid asm dependency.
return strings.IndexByte(args[0].(string), args[1].(byte))
}
func ext۰strings۰Index(fr *frame, args []value) value {
// Call compiled version to avoid asm dependency.
return strings.Index(args[0].(string), args[1].(string))
}
func ext۰runtime۰GOMAXPROCS(fr *frame, args []value) value {
// Ignore args[0]; don't let the interpreted program
// set the interpreter's GOMAXPROCS!
return runtime.GOMAXPROCS(0)
}
func ext۰runtime۰Goexit(fr *frame, args []value) value {
// TODO(adonovan): don't kill the interpreter's main goroutine.
runtime.Goexit()
return nil
}
func ext۰runtime۰GC(fr *frame, args []value) value {
runtime.GC()
return nil
}
func ext۰runtime۰Gosched(fr *frame, args []value) value {
runtime.Gosched()
return nil
}
func ext۰runtime۰NumCPU(fr *frame, args []value) value {
return runtime.NumCPU()
}
func ext۰runtime۰NumGoroutine(fr *frame, args []value) value {
return int(atomic.LoadInt32(&fr.i.goroutines))
}
func ext۰runtime۰ReadMemStats(fr *frame, args []value) value {
// TODO(adonovan): populate args[0].(Struct)
return nil
}
func ext۰atomic۰LoadUint32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
return (*args[0].(*value)).(uint32)
}
func ext۰atomic۰StoreUint32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
*args[0].(*value) = args[1].(uint32)
return nil
}
func ext۰atomic۰LoadInt32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
return (*args[0].(*value)).(int32)
}
func ext۰atomic۰StoreInt32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
*args[0].(*value) = args[1].(int32)
return nil
}
func ext۰atomic۰CompareAndSwapInt32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
if (*p).(int32) == args[1].(int32) {
*p = args[2].(int32)
return true
}
return false
}
func ext۰atomic۰CompareAndSwapUint32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
if (*p).(uint32) == args[1].(uint32) {
*p = args[2].(uint32)
return true
}
return false
}
func ext۰atomic۰AddInt32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
newv := (*p).(int32) + args[1].(int32)
*p = newv
return newv
}
func ext۰atomic۰AddUint32(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
newv := (*p).(uint32) + args[1].(uint32)
*p = newv
return newv
}
func ext۰atomic۰LoadUint64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
return (*args[0].(*value)).(uint64)
}
func ext۰atomic۰StoreUint64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
*args[0].(*value) = args[1].(uint64)
return nil
}
func ext۰atomic۰LoadInt64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
return (*args[0].(*value)).(int64)
}
func ext۰atomic۰StoreInt64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
*args[0].(*value) = args[1].(int64)
return nil
}
func ext۰atomic۰CompareAndSwapInt64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
if (*p).(int64) == args[1].(int64) {
*p = args[2].(int64)
return true
}
return false
}
func ext۰atomic۰CompareAndSwapUint64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
if (*p).(uint64) == args[1].(uint64) {
*p = args[2].(uint64)
return true
}
return false
}
func ext۰atomic۰AddInt64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
newv := (*p).(int64) + args[1].(int64)
*p = newv
return newv
}
func ext۰atomic۰AddUint64(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
p := args[0].(*value)
newv := (*p).(uint64) + args[1].(uint64)
*p = newv
return newv
}
func ext۰atomic۰ValueLoad(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
// Receiver is *struct{v interface{}}.
return (*args[0].(*value)).(structure)[0]
}
func ext۰atomic۰ValueStore(fr *frame, args []value) value {
// TODO(adonovan): fix: not atomic!
// Receiver is *struct{v interface{}}.
(*args[0].(*value)).(structure)[0] = args[1]
return nil
}
func ext۰cpu۰cpuid(fr *frame, args []value) value {
return tuple{uint32(0), uint32(0), uint32(0), uint32(0)}
}
func ext۰syscall۰unix۰syscall_fcntl(fr *frame, args []value) value {
return tuple{int(0), wrapError(nil)}
}
// Pretend: type runtime.Func struct { entry *ssa.Function }
func ext۰runtime۰Func۰FileLine(fr *frame, args []value) value {
// func (*runtime.Func) FileLine(uintptr) (string, int)
f, _ := (*args[0].(*value)).(structure)[0].(*ssa.Function)
pc := args[1].(uintptr)
_ = pc
if f != nil {
// TODO(adonovan): use position of current instruction, not fn.
posn := f.Prog.Fset.Position(f.Pos())
return tuple{posn.Filename, posn.Line}
}
return tuple{"", 0}
}
func ext۰runtime۰Func۰Name(fr *frame, args []value) value {
// func (*runtime.Func) Name() string
f, _ := (*args[0].(*value)).(structure)[0].(*ssa.Function)
if f != nil {
return f.String()
}
return ""
}
func ext۰runtime۰Func۰Entry(fr *frame, args []value) value {
// func (*runtime.Func) Entry() uintptr
f, _ := (*args[0].(*value)).(structure)[0].(*ssa.Function)
return uintptr(unsafe.Pointer(f))
}
func ext۰time۰now(fr *frame, args []value) value {
nano := time.Now().UnixNano()
return tuple{int64(nano / 1e9), int32(nano % 1e9), int64(0)}
}
func ext۰time۰Sleep(fr *frame, args []value) value {
time.Sleep(time.Duration(args[0].(int64)))
return nil
}
func valueToBytes(v value) []byte {
in := v.([]value)
b := make([]byte, len(in))
for i := range in {
b[i] = in[i].(byte)
}
return b
}
func ext۰testing۰MainStart(fr *frame, args []value) value {
// We no longer support interpretation of the "testing" package
// because it changes too often and uses low-level features that
// are a pain to emulate.
panic(`interpretation of the "testing" package is no longer supported`)
}