go expr 源码
golang expr 代码
文件路径：/src/cmd/compile/internal/walk/expr.go
// Copyright 2009 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 walk
import (
"fmt"
"go/constant"
"internal/buildcfg"
"strings"
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/staticdata"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/internal/obj"
)
// The result of walkExpr MUST be assigned back to n, e.g.
//
// n.Left = walkExpr(n.Left, init)
func walkExpr(n ir.Node, init *ir.Nodes) ir.Node {
if n == nil {
return n
}
if n, ok := n.(ir.InitNode); ok && init == n.PtrInit() {
// not okay to use n->ninit when walking n,
// because we might replace n with some other node
// and would lose the init list.
base.Fatalf("walkExpr init == &n->ninit")
}
if len(n.Init()) != 0 {
walkStmtList(n.Init())
init.Append(ir.TakeInit(n)...)
}
lno := ir.SetPos(n)
if base.Flag.LowerW > 1 {
ir.Dump("before walk expr", n)
}
if n.Typecheck() != 1 {
base.Fatalf("missed typecheck: %+v", n)
}
if n.Type().IsUntyped() {
base.Fatalf("expression has untyped type: %+v", n)
}
n = walkExpr1(n, init)
// Eagerly compute sizes of all expressions for the back end.
if typ := n.Type(); typ != nil && typ.Kind() != types.TBLANK && !typ.IsFuncArgStruct() {
types.CheckSize(typ)
}
if n, ok := n.(*ir.Name); ok && n.Heapaddr != nil {
types.CheckSize(n.Heapaddr.Type())
}
if ir.IsConst(n, constant.String) {
// Emit string symbol now to avoid emitting
// any concurrently during the backend.
_ = staticdata.StringSym(n.Pos(), constant.StringVal(n.Val()))
}
if base.Flag.LowerW != 0 && n != nil {
ir.Dump("after walk expr", n)
}
base.Pos = lno
return n
}
func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
switch n.Op() {
default:
ir.Dump("walk", n)
base.Fatalf("walkExpr: switch 1 unknown op %+v", n.Op())
panic("unreachable")
case ir.OGETG, ir.OGETCALLERPC, ir.OGETCALLERSP:
return n
case ir.OTYPE, ir.ONAME, ir.OLITERAL, ir.ONIL, ir.OLINKSYMOFFSET:
// TODO(mdempsky): Just return n; see discussion on CL 38655.
// Perhaps refactor to use Node.mayBeShared for these instead.
// If these return early, make sure to still call
// StringSym for constant strings.
return n
case ir.OMETHEXPR:
// TODO(mdempsky): Do this right after type checking.
n := n.(*ir.SelectorExpr)
return n.FuncName()
case ir.ONOT, ir.ONEG, ir.OPLUS, ir.OBITNOT, ir.OREAL, ir.OIMAG, ir.OSPTR, ir.OITAB, ir.OIDATA:
n := n.(*ir.UnaryExpr)
n.X = walkExpr(n.X, init)
return n
case ir.ODOTMETH, ir.ODOTINTER:
n := n.(*ir.SelectorExpr)
n.X = walkExpr(n.X, init)
return n
case ir.OADDR:
n := n.(*ir.AddrExpr)
n.X = walkExpr(n.X, init)
return n
case ir.ODEREF:
n := n.(*ir.StarExpr)
n.X = walkExpr(n.X, init)
return n
case ir.OEFACE, ir.OAND, ir.OANDNOT, ir.OSUB, ir.OMUL, ir.OADD, ir.OOR, ir.OXOR, ir.OLSH, ir.ORSH,
ir.OUNSAFEADD:
n := n.(*ir.BinaryExpr)
n.X = walkExpr(n.X, init)
n.Y = walkExpr(n.Y, init)
return n
case ir.OUNSAFESLICE:
n := n.(*ir.BinaryExpr)
return walkUnsafeSlice(n, init)
case ir.ODOT, ir.ODOTPTR:
n := n.(*ir.SelectorExpr)
return walkDot(n, init)
case ir.ODOTTYPE, ir.ODOTTYPE2:
n := n.(*ir.TypeAssertExpr)
return walkDotType(n, init)
case ir.ODYNAMICDOTTYPE, ir.ODYNAMICDOTTYPE2:
n := n.(*ir.DynamicTypeAssertExpr)
return walkDynamicDotType(n, init)
case ir.OLEN, ir.OCAP:
n := n.(*ir.UnaryExpr)
return walkLenCap(n, init)
case ir.OCOMPLEX:
n := n.(*ir.BinaryExpr)
n.X = walkExpr(n.X, init)
n.Y = walkExpr(n.Y, init)
return n
case ir.OEQ, ir.ONE, ir.OLT, ir.OLE, ir.OGT, ir.OGE:
n := n.(*ir.BinaryExpr)
return walkCompare(n, init)
case ir.OANDAND, ir.OOROR:
n := n.(*ir.LogicalExpr)
return walkLogical(n, init)
case ir.OPRINT, ir.OPRINTN:
return walkPrint(n.(*ir.CallExpr), init)
case ir.OPANIC:
n := n.(*ir.UnaryExpr)
return mkcall("gopanic", nil, init, n.X)
case ir.ORECOVERFP:
return walkRecoverFP(n.(*ir.CallExpr), init)
case ir.OCFUNC:
return n
case ir.OCALLINTER, ir.OCALLFUNC:
n := n.(*ir.CallExpr)
return walkCall(n, init)
case ir.OAS, ir.OASOP:
return walkAssign(init, n)
case ir.OAS2:
n := n.(*ir.AssignListStmt)
return walkAssignList(init, n)
// a,b,... = fn()
case ir.OAS2FUNC:
n := n.(*ir.AssignListStmt)
return walkAssignFunc(init, n)
// x, y = <-c
// order.stmt made sure x is addressable or blank.
case ir.OAS2RECV:
n := n.(*ir.AssignListStmt)
return walkAssignRecv(init, n)
// a,b = m[i]
case ir.OAS2MAPR:
n := n.(*ir.AssignListStmt)
return walkAssignMapRead(init, n)
case ir.ODELETE:
n := n.(*ir.CallExpr)
return walkDelete(init, n)
case ir.OAS2DOTTYPE:
n := n.(*ir.AssignListStmt)
return walkAssignDotType(n, init)
case ir.OCONVIFACE:
n := n.(*ir.ConvExpr)
return walkConvInterface(n, init)
case ir.OCONVIDATA:
n := n.(*ir.ConvExpr)
return walkConvIData(n, init)
case ir.OCONV, ir.OCONVNOP:
n := n.(*ir.ConvExpr)
return walkConv(n, init)
case ir.OSLICE2ARRPTR:
n := n.(*ir.ConvExpr)
n.X = walkExpr(n.X, init)
return n
case ir.ODIV, ir.OMOD:
n := n.(*ir.BinaryExpr)
return walkDivMod(n, init)
case ir.OINDEX:
n := n.(*ir.IndexExpr)
return walkIndex(n, init)
case ir.OINDEXMAP:
n := n.(*ir.IndexExpr)
return walkIndexMap(n, init)
case ir.ORECV:
base.Fatalf("walkExpr ORECV") // should see inside OAS only
panic("unreachable")
case ir.OSLICEHEADER:
n := n.(*ir.SliceHeaderExpr)
return walkSliceHeader(n, init)
case ir.OSLICE, ir.OSLICEARR, ir.OSLICESTR, ir.OSLICE3, ir.OSLICE3ARR:
n := n.(*ir.SliceExpr)
return walkSlice(n, init)
case ir.ONEW:
n := n.(*ir.UnaryExpr)
return walkNew(n, init)
case ir.OADDSTR:
return walkAddString(n.(*ir.AddStringExpr), init)
case ir.OAPPEND:
// order should make sure we only see OAS(node, OAPPEND), which we handle above.
base.Fatalf("append outside assignment")
panic("unreachable")
case ir.OCOPY:
return walkCopy(n.(*ir.BinaryExpr), init, base.Flag.Cfg.Instrumenting && !base.Flag.CompilingRuntime)
case ir.OCLOSE:
n := n.(*ir.UnaryExpr)
return walkClose(n, init)
case ir.OMAKECHAN:
n := n.(*ir.MakeExpr)
return walkMakeChan(n, init)
case ir.OMAKEMAP:
n := n.(*ir.MakeExpr)
return walkMakeMap(n, init)
case ir.OMAKESLICE:
n := n.(*ir.MakeExpr)
return walkMakeSlice(n, init)
case ir.OMAKESLICECOPY:
n := n.(*ir.MakeExpr)
return walkMakeSliceCopy(n, init)
case ir.ORUNESTR:
n := n.(*ir.ConvExpr)
return walkRuneToString(n, init)
case ir.OBYTES2STR, ir.ORUNES2STR:
n := n.(*ir.ConvExpr)
return walkBytesRunesToString(n, init)
case ir.OBYTES2STRTMP:
n := n.(*ir.ConvExpr)
return walkBytesToStringTemp(n, init)
case ir.OSTR2BYTES:
n := n.(*ir.ConvExpr)
return walkStringToBytes(n, init)
case ir.OSTR2BYTESTMP:
n := n.(*ir.ConvExpr)
return walkStringToBytesTemp(n, init)
case ir.OSTR2RUNES:
n := n.(*ir.ConvExpr)
return walkStringToRunes(n, init)
case ir.OARRAYLIT, ir.OSLICELIT, ir.OMAPLIT, ir.OSTRUCTLIT, ir.OPTRLIT:
return walkCompLit(n, init)
case ir.OSEND:
n := n.(*ir.SendStmt)
return walkSend(n, init)
case ir.OCLOSURE:
return walkClosure(n.(*ir.ClosureExpr), init)
case ir.OMETHVALUE:
return walkMethodValue(n.(*ir.SelectorExpr), init)
}
// No return! Each case must return (or panic),
// to avoid confusion about what gets returned
// in the presence of type assertions.
}
// walk the whole tree of the body of an
// expression or simple statement.
// the types expressions are calculated.
// compile-time constants are evaluated.
// complex side effects like statements are appended to init
func walkExprList(s []ir.Node, init *ir.Nodes) {
for i := range s {
s[i] = walkExpr(s[i], init)
}
}
func walkExprListCheap(s []ir.Node, init *ir.Nodes) {
for i, n := range s {
s[i] = cheapExpr(n, init)
s[i] = walkExpr(s[i], init)
}
}
func walkExprListSafe(s []ir.Node, init *ir.Nodes) {
for i, n := range s {
s[i] = safeExpr(n, init)
s[i] = walkExpr(s[i], init)
}
}
// return side-effect free and cheap n, appending side effects to init.
// result may not be assignable.
func cheapExpr(n ir.Node, init *ir.Nodes) ir.Node {
switch n.Op() {
case ir.ONAME, ir.OLITERAL, ir.ONIL:
return n
}
return copyExpr(n, n.Type(), init)
}
// return side effect-free n, appending side effects to init.
// result is assignable if n is.
func safeExpr(n ir.Node, init *ir.Nodes) ir.Node {
if n == nil {
return nil
}
if len(n.Init()) != 0 {
walkStmtList(n.Init())
init.Append(ir.TakeInit(n)...)
}
switch n.Op() {
case ir.ONAME, ir.OLITERAL, ir.ONIL, ir.OLINKSYMOFFSET:
return n
case ir.OLEN, ir.OCAP:
n := n.(*ir.UnaryExpr)
l := safeExpr(n.X, init)
if l == n.X {
return n
}
a := ir.Copy(n).(*ir.UnaryExpr)
a.X = l
return walkExpr(typecheck.Expr(a), init)
case ir.ODOT, ir.ODOTPTR:
n := n.(*ir.SelectorExpr)
l := safeExpr(n.X, init)
if l == n.X {
return n
}
a := ir.Copy(n).(*ir.SelectorExpr)
a.X = l
return walkExpr(typecheck.Expr(a), init)
case ir.ODEREF:
n := n.(*ir.StarExpr)
l := safeExpr(n.X, init)
if l == n.X {
return n
}
a := ir.Copy(n).(*ir.StarExpr)
a.X = l
return walkExpr(typecheck.Expr(a), init)
case ir.OINDEX, ir.OINDEXMAP:
n := n.(*ir.IndexExpr)
l := safeExpr(n.X, init)
r := safeExpr(n.Index, init)
if l == n.X && r == n.Index {
return n
}
a := ir.Copy(n).(*ir.IndexExpr)
a.X = l
a.Index = r
return walkExpr(typecheck.Expr(a), init)
case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
n := n.(*ir.CompLitExpr)
if isStaticCompositeLiteral(n) {
return n
}
}
// make a copy; must not be used as an lvalue
if ir.IsAddressable(n) {
base.Fatalf("missing lvalue case in safeExpr: %v", n)
}
return cheapExpr(n, init)
}
func copyExpr(n ir.Node, t *types.Type, init *ir.Nodes) ir.Node {
l := typecheck.Temp(t)
appendWalkStmt(init, ir.NewAssignStmt(base.Pos, l, n))
return l
}
func walkAddString(n *ir.AddStringExpr, init *ir.Nodes) ir.Node {
c := len(n.List)
if c < 2 {
base.Fatalf("walkAddString count %d too small", c)
}
buf := typecheck.NodNil()
if n.Esc() == ir.EscNone {
sz := int64(0)
for _, n1 := range n.List {
if n1.Op() == ir.OLITERAL {
sz += int64(len(ir.StringVal(n1)))
}
}
// Don't allocate the buffer if the result won't fit.
if sz < tmpstringbufsize {
// Create temporary buffer for result string on stack.
buf = stackBufAddr(tmpstringbufsize, types.Types[types.TUINT8])
}
}
// build list of string arguments
args := []ir.Node{buf}
for _, n2 := range n.List {
args = append(args, typecheck.Conv(n2, types.Types[types.TSTRING]))
}
var fn string
if c <= 5 {
// small numbers of strings use direct runtime helpers.
// note: order.expr knows this cutoff too.
fn = fmt.Sprintf("concatstring%d", c)
} else {
// large numbers of strings are passed to the runtime as a slice.
fn = "concatstrings"
t := types.NewSlice(types.Types[types.TSTRING])
// args[1:] to skip buf arg
slice := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, t, args[1:])
slice.Prealloc = n.Prealloc
args = []ir.Node{buf, slice}
slice.SetEsc(ir.EscNone)
}
cat := typecheck.LookupRuntime(fn)
r := ir.NewCallExpr(base.Pos, ir.OCALL, cat, nil)
r.Args = args
r1 := typecheck.Expr(r)
r1 = walkExpr(r1, init)
r1.SetType(n.Type())
return r1
}
type hookInfo struct {
paramType types.Kind
argsNum int
runtimeFunc string
}
var hooks = map[string]hookInfo{
"strings.EqualFold": {paramType: types.TSTRING, argsNum: 2, runtimeFunc: "libfuzzerHookEqualFold"},
}
// walkCall walks an OCALLFUNC or OCALLINTER node.
func walkCall(n *ir.CallExpr, init *ir.Nodes) ir.Node {
if n.Op() == ir.OCALLMETH {
base.FatalfAt(n.Pos(), "OCALLMETH missed by typecheck")
}
if n.Op() == ir.OCALLINTER || n.X.Op() == ir.OMETHEXPR {
// We expect both interface call reflect.Type.Method and concrete
// call reflect.(*rtype).Method.
usemethod(n)
}
if n.Op() == ir.OCALLINTER {
reflectdata.MarkUsedIfaceMethod(n)
}
if n.Op() == ir.OCALLFUNC && n.X.Op() == ir.OCLOSURE {
directClosureCall(n)
}
if isFuncPCIntrinsic(n) {
// For internal/abi.FuncPCABIxxx(fn), if fn is a defined function, rewrite
// it to the address of the function of the ABI fn is defined.
name := n.X.(*ir.Name).Sym().Name
arg := n.Args[0]
var wantABI obj.ABI
switch name {
case "FuncPCABI0":
wantABI = obj.ABI0
case "FuncPCABIInternal":
wantABI = obj.ABIInternal
}
if isIfaceOfFunc(arg) {
fn := arg.(*ir.ConvExpr).X.(*ir.Name)
abi := fn.Func.ABI
if abi != wantABI {
base.ErrorfAt(n.Pos(), "internal/abi.%s expects an %v function, %s is defined as %v", name, wantABI, fn.Sym().Name, abi)
}
var e ir.Node = ir.NewLinksymExpr(n.Pos(), fn.Sym().LinksymABI(abi), types.Types[types.TUINTPTR])
e = ir.NewAddrExpr(n.Pos(), e)
e.SetType(types.Types[types.TUINTPTR].PtrTo())
e = ir.NewConvExpr(n.Pos(), ir.OCONVNOP, n.Type(), e)
return e
}
// fn is not a defined function. It must be ABIInternal.
// Read the address from func value, i.e. *(*uintptr)(idata(fn)).
if wantABI != obj.ABIInternal {
base.ErrorfAt(n.Pos(), "internal/abi.%s does not accept func expression, which is ABIInternal", name)
}
arg = walkExpr(arg, init)
var e ir.Node = ir.NewUnaryExpr(n.Pos(), ir.OIDATA, arg)
e.SetType(n.Type().PtrTo())
e = ir.NewStarExpr(n.Pos(), e)
e.SetType(n.Type())
return e
}
walkCall1(n, init)
return n
}
func walkCall1(n *ir.CallExpr, init *ir.Nodes) {
if n.Walked() {
return // already walked
}
n.SetWalked(true)
if n.Op() == ir.OCALLMETH {
base.FatalfAt(n.Pos(), "OCALLMETH missed by typecheck")
}
args := n.Args
params := n.X.Type().Params()
n.X = walkExpr(n.X, init)
walkExprList(args, init)
for i, arg := range args {
// Validate argument and parameter types match.
param := params.Field(i)
if !types.Identical(arg.Type(), param.Type) {
base.FatalfAt(n.Pos(), "assigning %L to parameter %v (type %v)", arg, param.Sym, param.Type)
}
// For any argument whose evaluation might require a function call,
// store that argument into a temporary variable,
// to prevent that calls from clobbering arguments already on the stack.
if mayCall(arg) {
// assignment of arg to Temp
tmp := typecheck.Temp(param.Type)
init.Append(convas(typecheck.Stmt(ir.NewAssignStmt(base.Pos, tmp, arg)).(*ir.AssignStmt), init))
// replace arg with temp
args[i] = tmp
}
}
n.Args = args
funSym := n.X.Sym()
if base.Debug.Libfuzzer != 0 && funSym != nil {
if hook, found := hooks[funSym.Pkg.Path+"."+funSym.Name]; found {
if len(args) != hook.argsNum {
panic(fmt.Sprintf("%s.%s expects %d arguments, but received %d", funSym.Pkg.Path, funSym.Name, hook.argsNum, len(args)))
}
var hookArgs []ir.Node
for _, arg := range args {
hookArgs = append(hookArgs, tracecmpArg(arg, types.Types[hook.paramType], init))
}
hookArgs = append(hookArgs, fakePC(n))
init.Append(mkcall(hook.runtimeFunc, nil, init, hookArgs...))
}
}
}
// walkDivMod walks an ODIV or OMOD node.
func walkDivMod(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
n.Y = walkExpr(n.Y, init)
// rewrite complex div into function call.
et := n.X.Type().Kind()
if types.IsComplex[et] && n.Op() == ir.ODIV {
t := n.Type()
call := mkcall("complex128div", types.Types[types.TCOMPLEX128], init, typecheck.Conv(n.X, types.Types[types.TCOMPLEX128]), typecheck.Conv(n.Y, types.Types[types.TCOMPLEX128]))
return typecheck.Conv(call, t)
}
// Nothing to do for float divisions.
if types.IsFloat[et] {
return n
}
// rewrite 64-bit div and mod on 32-bit architectures.
// TODO: Remove this code once we can introduce
// runtime calls late in SSA processing.
if types.RegSize < 8 && (et == types.TINT64 || et == types.TUINT64) {
if n.Y.Op() == ir.OLITERAL {
// Leave div/mod by constant powers of 2 or small 16-bit constants.
// The SSA backend will handle those.
switch et {
case types.TINT64:
c := ir.Int64Val(n.Y)
if c < 0 {
c = -c
}
if c != 0 && c&(c-1) == 0 {
return n
}
case types.TUINT64:
c := ir.Uint64Val(n.Y)
if c < 1<<16 {
return n
}
if c != 0 && c&(c-1) == 0 {
return n
}
}
}
var fn string
if et == types.TINT64 {
fn = "int64"
} else {
fn = "uint64"
}
if n.Op() == ir.ODIV {
fn += "div"
} else {
fn += "mod"
}
return mkcall(fn, n.Type(), init, typecheck.Conv(n.X, types.Types[et]), typecheck.Conv(n.Y, types.Types[et]))
}
return n
}
// walkDot walks an ODOT or ODOTPTR node.
func walkDot(n *ir.SelectorExpr, init *ir.Nodes) ir.Node {
usefield(n)
n.X = walkExpr(n.X, init)
return n
}
// walkDotType walks an ODOTTYPE or ODOTTYPE2 node.
func walkDotType(n *ir.TypeAssertExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
// Set up interface type addresses for back end.
if !n.Type().IsInterface() && !n.X.Type().IsEmptyInterface() {
n.ITab = reflectdata.ITabAddr(n.Type(), n.X.Type())
}
return n
}
// walkDynamicdotType walks an ODYNAMICDOTTYPE or ODYNAMICDOTTYPE2 node.
func walkDynamicDotType(n *ir.DynamicTypeAssertExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
n.RType = walkExpr(n.RType, init)
n.ITab = walkExpr(n.ITab, init)
return n
}
// walkIndex walks an OINDEX node.
func walkIndex(n *ir.IndexExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
// save the original node for bounds checking elision.
// If it was a ODIV/OMOD walk might rewrite it.
r := n.Index
n.Index = walkExpr(n.Index, init)
// if range of type cannot exceed static array bound,
// disable bounds check.
if n.Bounded() {
return n
}
t := n.X.Type()
if t != nil && t.IsPtr() {
t = t.Elem()
}
if t.IsArray() {
n.SetBounded(bounded(r, t.NumElem()))
if base.Flag.LowerM != 0 && n.Bounded() && !ir.IsConst(n.Index, constant.Int) {
base.Warn("index bounds check elided")
}
if ir.IsSmallIntConst(n.Index) && !n.Bounded() {
base.Errorf("index out of bounds")
}
} else if ir.IsConst(n.X, constant.String) {
n.SetBounded(bounded(r, int64(len(ir.StringVal(n.X)))))
if base.Flag.LowerM != 0 && n.Bounded() && !ir.IsConst(n.Index, constant.Int) {
base.Warn("index bounds check elided")
}
if ir.IsSmallIntConst(n.Index) && !n.Bounded() {
base.Errorf("index out of bounds")
}
}
if ir.IsConst(n.Index, constant.Int) {
if v := n.Index.Val(); constant.Sign(v) < 0 || ir.ConstOverflow(v, types.Types[types.TINT]) {
base.Errorf("index out of bounds")
}
}
return n
}
// mapKeyArg returns an expression for key that is suitable to be passed
// as the key argument for runtime map* functions.
// n is is the map indexing or delete Node (to provide Pos).
func mapKeyArg(fast int, n, key ir.Node, assigned bool) ir.Node {
if fast == mapslow {
// standard version takes key by reference.
// orderState.expr made sure key is addressable.
return typecheck.NodAddr(key)
}
if assigned {
// mapassign does distinguish pointer vs. integer key.
return key
}
// mapaccess and mapdelete don't distinguish pointer vs. integer key.
switch fast {
case mapfast32ptr:
return ir.NewConvExpr(n.Pos(), ir.OCONVNOP, types.Types[types.TUINT32], key)
case mapfast64ptr:
return ir.NewConvExpr(n.Pos(), ir.OCONVNOP, types.Types[types.TUINT64], key)
default:
// fast version takes key by value.
return key
}
}
// walkIndexMap walks an OINDEXMAP node.
// It replaces m[k] with *map{access1,assign}(maptype, m, &k)
func walkIndexMap(n *ir.IndexExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
n.Index = walkExpr(n.Index, init)
map_ := n.X
t := map_.Type()
fast := mapfast(t)
key := mapKeyArg(fast, n, n.Index, n.Assigned)
args := []ir.Node{reflectdata.TypePtr(t), map_, key}
var mapFn ir.Node
switch {
case n.Assigned:
mapFn = mapfn(mapassign[fast], t, false)
case t.Elem().Size() > zeroValSize:
args = append(args, reflectdata.ZeroAddr(t.Elem().Size()))
mapFn = mapfn("mapaccess1_fat", t, true)
default:
mapFn = mapfn(mapaccess1[fast], t, false)
}
call := mkcall1(mapFn, nil, init, args...)
call.SetType(types.NewPtr(t.Elem()))
call.MarkNonNil() // mapaccess1* and mapassign always return non-nil pointers.
star := ir.NewStarExpr(base.Pos, call)
star.SetType(t.Elem())
star.SetTypecheck(1)
return star
}
// walkLogical walks an OANDAND or OOROR node.
func walkLogical(n *ir.LogicalExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
// cannot put side effects from n.Right on init,
// because they cannot run before n.Left is checked.
// save elsewhere and store on the eventual n.Right.
var ll ir.Nodes
n.Y = walkExpr(n.Y, &ll)
n.Y = ir.InitExpr(ll, n.Y)
return n
}
// walkSend walks an OSEND node.
func walkSend(n *ir.SendStmt, init *ir.Nodes) ir.Node {
n1 := n.Value
n1 = typecheck.AssignConv(n1, n.Chan.Type().Elem(), "chan send")
n1 = walkExpr(n1, init)
n1 = typecheck.NodAddr(n1)
return mkcall1(chanfn("chansend1", 2, n.Chan.Type()), nil, init, n.Chan, n1)
}
// walkSlice walks an OSLICE, OSLICEARR, OSLICESTR, OSLICE3, or OSLICE3ARR node.
func walkSlice(n *ir.SliceExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
n.Low = walkExpr(n.Low, init)
if n.Low != nil && ir.IsZero(n.Low) {
// Reduce x[0:j] to x[:j] and x[0:j:k] to x[:j:k].
n.Low = nil
}
n.High = walkExpr(n.High, init)
n.Max = walkExpr(n.Max, init)
if n.Op().IsSlice3() {
if n.Max != nil && n.Max.Op() == ir.OCAP && ir.SameSafeExpr(n.X, n.Max.(*ir.UnaryExpr).X) {
// Reduce x[i:j:cap(x)] to x[i:j].
if n.Op() == ir.OSLICE3 {
n.SetOp(ir.OSLICE)
} else {
n.SetOp(ir.OSLICEARR)
}
return reduceSlice(n)
}
return n
}
return reduceSlice(n)
}
// walkSliceHeader walks an OSLICEHEADER node.
func walkSliceHeader(n *ir.SliceHeaderExpr, init *ir.Nodes) ir.Node {
n.Ptr = walkExpr(n.Ptr, init)
n.Len = walkExpr(n.Len, init)
n.Cap = walkExpr(n.Cap, init)
return n
}
// TODO(josharian): combine this with its caller and simplify
func reduceSlice(n *ir.SliceExpr) ir.Node {
if n.High != nil && n.High.Op() == ir.OLEN && ir.SameSafeExpr(n.X, n.High.(*ir.UnaryExpr).X) {
// Reduce x[i:len(x)] to x[i:].
n.High = nil
}
if (n.Op() == ir.OSLICE || n.Op() == ir.OSLICESTR) && n.Low == nil && n.High == nil {
// Reduce x[:] to x.
if base.Debug.Slice > 0 {
base.Warn("slice: omit slice operation")
}
return n.X
}
return n
}
// return 1 if integer n must be in range [0, max), 0 otherwise
func bounded(n ir.Node, max int64) bool {
if n.Type() == nil || !n.Type().IsInteger() {
return false
}
sign := n.Type().IsSigned()
bits := int32(8 * n.Type().Size())
if ir.IsSmallIntConst(n) {
v := ir.Int64Val(n)
return 0 <= v && v < max
}
switch n.Op() {
case ir.OAND, ir.OANDNOT:
n := n.(*ir.BinaryExpr)
v := int64(-1)
switch {
case ir.IsSmallIntConst(n.X):
v = ir.Int64Val(n.X)
case ir.IsSmallIntConst(n.Y):
v = ir.Int64Val(n.Y)
if n.Op() == ir.OANDNOT {
v = ^v
if !sign {
v &= 1<<uint(bits) - 1
}
}
}
if 0 <= v && v < max {
return true
}
case ir.OMOD:
n := n.(*ir.BinaryExpr)
if !sign && ir.IsSmallIntConst(n.Y) {
v := ir.Int64Val(n.Y)
if 0 <= v && v <= max {
return true
}
}
case ir.ODIV:
n := n.(*ir.BinaryExpr)
if !sign && ir.IsSmallIntConst(n.Y) {
v := ir.Int64Val(n.Y)
for bits > 0 && v >= 2 {
bits--
v >>= 1
}
}
case ir.ORSH:
n := n.(*ir.BinaryExpr)
if !sign && ir.IsSmallIntConst(n.Y) {
v := ir.Int64Val(n.Y)
if v > int64(bits) {
return true
}
bits -= int32(v)
}
}
if !sign && bits <= 62 && 1<<uint(bits) <= max {
return true
}
return false
}
// usemethod checks calls for uses of reflect.Type.{Method,MethodByName}.
func usemethod(n *ir.CallExpr) {
// Don't mark reflect.(*rtype).Method, etc. themselves in the reflect package.
// Those functions may be alive via the itab, which should not cause all methods
// alive. We only want to mark their callers.
if base.Ctxt.Pkgpath == "reflect" {
switch ir.CurFunc.Nname.Sym().Name { // TODO: is there a better way than hardcoding the names?
case "(*rtype).Method", "(*rtype).MethodByName", "(*interfaceType).Method", "(*interfaceType).MethodByName":
return
}
}
dot, ok := n.X.(*ir.SelectorExpr)
if !ok {
return
}
// Looking for either direct method calls and interface method calls of:
// reflect.Type.Method - func(int) reflect.Method
// reflect.Type.MethodByName - func(string) (reflect.Method, bool)
var pKind types.Kind
switch dot.Sel.Name {
case "Method":
pKind = types.TINT
case "MethodByName":
pKind = types.TSTRING
default:
return
}
t := dot.Selection.Type
if t.NumParams() != 1 || t.Params().Field(0).Type.Kind() != pKind {
return
}
switch t.NumResults() {
case 1:
// ok
case 2:
if t.Results().Field(1).Type.Kind() != types.TBOOL {
return
}
default:
return
}
// Check that first result type is "reflect.Method". Note that we have to check sym name and sym package
// separately, as we can't check for exact string "reflect.Method" reliably (e.g., see #19028 and #38515).
if s := t.Results().Field(0).Type.Sym(); s != nil && s.Name == "Method" && types.IsReflectPkg(s.Pkg) {
ir.CurFunc.SetReflectMethod(true)
// The LSym is initialized at this point. We need to set the attribute on the LSym.
ir.CurFunc.LSym.Set(obj.AttrReflectMethod, true)
}
}
func usefield(n *ir.SelectorExpr) {
if !buildcfg.Experiment.FieldTrack {
return
}
switch n.Op() {
default:
base.Fatalf("usefield %v", n.Op())
case ir.ODOT, ir.ODOTPTR:
break
}
field := n.Selection
if field == nil {
base.Fatalf("usefield %v %v without paramfld", n.X.Type(), n.Sel)
}
if field.Sym != n.Sel {
base.Fatalf("field inconsistency: %v != %v", field.Sym, n.Sel)
}
if !strings.Contains(field.Note, "go:\"track\"") {
return
}
outer := n.X.Type()
if outer.IsPtr() {
outer = outer.Elem()
}
if outer.Sym() == nil {
base.Errorf("tracked field must be in named struct type")
}
sym := reflectdata.TrackSym(outer, field)
if ir.CurFunc.FieldTrack == nil {
ir.CurFunc.FieldTrack = make(map[*obj.LSym]struct{})
}
ir.CurFunc.FieldTrack[sym] = struct{}{}
}
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