// visitInstr interprets a single ssa.Instruction within the activation
// record frame. It returns a continuation value indicating where to
// read the next instruction from.
func visitInstr(fr *frame, instr ssa.Instruction) continuation {
switch instr := instr.(type) {
case *ssa.DebugRef:
// no-op
case *ssa.UnOp:
fr.env[instr] = unop(instr, fr.get(instr.X))
case *ssa.BinOp:
fr.env[instr] = binop(instr.Op, instr.X.Type(), fr.get(instr.X), fr.get(instr.Y))
case *ssa.Call:
fn, args := prepareCall(fr, &instr.Call)
fr.env[instr] = call(fr.i, fr, instr.Pos(), fn, args)
case *ssa.ChangeInterface:
fr.env[instr] = fr.get(instr.X)
case *ssa.ChangeType:
fr.env[instr] = fr.get(instr.X) // (can't fail)
case *ssa.Convert:
fr.env[instr] = conv(instr.Type(), instr.X.Type(), fr.get(instr.X))
case *ssa.MakeInterface:
fr.env[instr] = iface{t: instr.X.Type(), v: fr.get(instr.X)}
case *ssa.Extract:
fr.env[instr] = fr.get(instr.Tuple).(tuple)[instr.Index]
case *ssa.Slice:
fr.env[instr] = slice(fr.get(instr.X), fr.get(instr.Low), fr.get(instr.High), fr.get(instr.Max))
case *ssa.Return:
switch len(instr.Results) {
case 0:
case 1:
fr.result = fr.get(instr.Results[0])
default:
var res []value
for _, r := range instr.Results {
res = append(res, fr.get(r))
}
fr.result = tuple(res)
}
fr.block = nil
return kReturn
case *ssa.RunDefers:
fr.runDefers()
case *ssa.Panic:
panic(targetPanic{fr.get(instr.X)})
case *ssa.Send:
fr.get(instr.Chan).(chan value) <- copyVal(fr.get(instr.X))
case *ssa.Store:
*fr.get(instr.Addr).(*value) = copyVal(fr.get(instr.Val))
case *ssa.If:
succ := 1
if fr.get(instr.Cond).(bool) {
succ = 0
}
fr.prevBlock, fr.block = fr.block, fr.block.Succs[succ]
return kJump
case *ssa.Jump:
fr.prevBlock, fr.block = fr.block, fr.block.Succs[0]
return kJump
case *ssa.Defer:
fn, args := prepareCall(fr, &instr.Call)
fr.defers = &deferred{
fn: fn,
args: args,
instr: instr,
tail: fr.defers,
}
case *ssa.Go:
fn, args := prepareCall(fr, &instr.Call)
go call(fr.i, nil, instr.Pos(), fn, args)
case *ssa.MakeChan:
fr.env[instr] = make(chan value, asInt(fr.get(instr.Size)))
case *ssa.Alloc:
var addr *value
if instr.Heap {
// new
addr = new(value)
fr.env[instr] = addr
} else {
// local
addr = fr.env[instr].(*value)
}
*addr = zero(deref(instr.Type()))
case *ssa.MakeSlice:
slice := make([]value, asInt(fr.get(instr.Cap)))
tElt := instr.Type().Underlying().(*types.Slice).Elem()
for i := range slice {
slice[i] = zero(tElt)
}
fr.env[instr] = slice[:asInt(fr.get(instr.Len))]
case *ssa.MakeMap:
reserve := 0
if instr.Reserve != nil {
reserve = asInt(fr.get(instr.Reserve))
}
fr.env[instr] = makeMap(instr.Type().Underlying().(*types.Map).Key(), reserve)
case *ssa.Range:
fr.env[instr] = rangeIter(fr.get(instr.X), instr.X.Type())
case *ssa.Next:
fr.env[instr] = fr.get(instr.Iter).(iter).next()
case *ssa.FieldAddr:
x := fr.get(instr.X)
fr.env[instr] = &(*x.(*value)).(structure)[instr.Field]
case *ssa.Field:
fr.env[instr] = copyVal(fr.get(instr.X).(structure)[instr.Field])
case *ssa.IndexAddr:
x := fr.get(instr.X)
idx := fr.get(instr.Index)
switch x := x.(type) {
case []value:
fr.env[instr] = &x[asInt(idx)]
case *value: // *array
fr.env[instr] = &(*x).(array)[asInt(idx)]
default:
panic(fmt.Sprintf("unexpected x type in IndexAddr: %T", x))
}
case *ssa.Index:
fr.env[instr] = copyVal(fr.get(instr.X).(array)[asInt(fr.get(instr.Index))])
case *ssa.Lookup:
fr.env[instr] = lookup(instr, fr.get(instr.X), fr.get(instr.Index))
case *ssa.MapUpdate:
m := fr.get(instr.Map)
key := fr.get(instr.Key)
v := fr.get(instr.Value)
switch m := m.(type) {
case map[value]value:
m[key] = v
case *hashmap:
m.insert(key.(hashable), v)
default:
panic(fmt.Sprintf("illegal map type: %T", m))
}
case *ssa.TypeAssert:
fr.env[instr] = typeAssert(fr.i, instr, fr.get(instr.X).(iface))
case *ssa.MakeClosure:
var bindings []value
for _, binding := range instr.Bindings {
bindings = append(bindings, fr.get(binding))
}
fr.env[instr] = &closure{instr.Fn.(*ssa.Function), bindings}
case *ssa.Phi:
for i, pred := range instr.Block().Preds {
if fr.prevBlock == pred {
fr.env[instr] = fr.get(instr.Edges[i])
break
}
}
case *ssa.Select:
var cases []reflect.SelectCase
if !instr.Blocking {
cases = append(cases, reflect.SelectCase{
Dir: reflect.SelectDefault,
})
}
for _, state := range instr.States {
var dir reflect.SelectDir
if state.Dir == types.RecvOnly {
dir = reflect.SelectRecv
} else {
dir = reflect.SelectSend
}
var send reflect.Value
if state.Send != nil {
send = reflect.ValueOf(fr.get(state.Send))
}
cases = append(cases, reflect.SelectCase{
Dir: dir,
Chan: reflect.ValueOf(fr.get(state.Chan)),
Send: send,
})
}
chosen, recv, recvOk := reflect.Select(cases)
if !instr.Blocking {
chosen-- // default case should have index -1.
}
r := tuple{chosen, recvOk}
for i, st := range instr.States {
if st.Dir == types.RecvOnly {
var v value
if i == chosen && recvOk {
// No need to copy since send makes an unaliased copy.
v = recv.Interface().(value)
} else {
v = zero(st.Chan.Type().Underlying().(*types.Chan).Elem())
}
r = append(r, v)
}
}
fr.env[instr] = r
default:
panic(fmt.Sprintf("unexpected instruction: %T", instr))
}
// if val, ok := instr.(ssa.Value); ok {
// fmt.Println(toString(fr.env[val])) // debugging
// }
return kNext
}
func (fr *frame) instruction(instr ssa.Instruction) {
fr.logf("[%T] %v @ %s\n", instr, instr, fr.pkg.Prog.Fset.Position(instr.Pos()))
if fr.GenerateDebug {
fr.debug.setLocation(fr.builder, instr.Pos())
}
// Check if we'll need to backpatch; see comment
// in fr.value().
if v, ok := instr.(ssa.Value); ok {
if b := fr.backpatcher(v); b != nil {
defer b()
}
}
switch instr := instr.(type) {
case *ssa.Alloc:
typ := fr.llvmtypes.ToLLVM(deref(instr.Type()))
var value llvm.Value
if instr.Heap {
value = fr.createTypeMalloc(typ)
value.SetName(instr.Comment)
fr.env[instr] = fr.NewValue(value, instr.Type())
} else {
value = fr.env[instr].LLVMValue()
}
fr.memsetZero(value, llvm.SizeOf(typ))
case *ssa.BinOp:
lhs, rhs := fr.value(instr.X), fr.value(instr.Y)
fr.env[instr] = lhs.BinaryOp(instr.Op, rhs).(*LLVMValue)
case *ssa.Call:
fn, args, result := fr.prepareCall(instr)
// Some builtins may only be used immediately, and not
// deferred; in this case, "fn" will be nil, and result
// may be non-nil (it will be nil for builtins without
// results.)
if fn == nil {
if result != nil {
fr.env[instr] = result
}
} else {
result = fr.createCall(fn, args)
fr.env[instr] = result
}
case *ssa.ChangeInterface:
x := fr.value(instr.X)
// The source type must be a non-empty interface,
// as ChangeInterface cannot fail (E2I may fail).
if instr.Type().Underlying().(*types.Interface).NumMethods() > 0 {
// TODO(axw) optimisation for I2I case where we
// know statically the methods to carry over.
x = x.convertI2E()
x, _ = x.convertE2I(instr.Type())
} else {
x = x.convertI2E()
x = fr.NewValue(x.LLVMValue(), instr.Type())
}
fr.env[instr] = x
case *ssa.ChangeType:
value := fr.value(instr.X).LLVMValue()
if _, ok := instr.Type().Underlying().(*types.Pointer); ok {
value = fr.builder.CreateBitCast(value, fr.llvmtypes.ToLLVM(instr.Type()), "")
}
v := fr.NewValue(value, instr.Type())
if _, ok := instr.X.(*ssa.Phi); ok {
v = phiValue(fr.compiler, v)
}
fr.env[instr] = v
case *ssa.Convert:
v := fr.value(instr.X)
if _, ok := instr.X.(*ssa.Phi); ok {
v = phiValue(fr.compiler, v)
}
fr.env[instr] = v.Convert(instr.Type()).(*LLVMValue)
//case *ssa.DebugRef:
case *ssa.Defer:
fn, args, result := fr.prepareCall(instr)
if result != nil {
panic("illegal use of builtin in defer statement")
}
fn = fr.indirectFunction(fn, args)
fr.createCall(fr.runtime.pushdefer, []*LLVMValue{fn})
case *ssa.Extract:
tuple := fr.value(instr.Tuple).LLVMValue()
elem := fr.builder.CreateExtractValue(tuple, instr.Index, instr.Name())
elemtyp := instr.Type()
fr.env[instr] = fr.NewValue(elem, elemtyp)
case *ssa.Field:
value := fr.value(instr.X).LLVMValue()
field := fr.builder.CreateExtractValue(value, instr.Field, instr.Name())
fieldtyp := instr.Type()
fr.env[instr] = fr.NewValue(field, fieldtyp)
case *ssa.FieldAddr:
// TODO: implement nil check and panic.
// TODO: combine a chain of {Field,Index}Addrs into a single GEP.
ptr := fr.value(instr.X).LLVMValue()
fieldptr := fr.builder.CreateStructGEP(ptr, instr.Field, instr.Name())
fieldptrtyp := instr.Type()
fr.env[instr] = fr.NewValue(fieldptr, fieldptrtyp)
case *ssa.Go:
fn, args, result := fr.prepareCall(instr)
if result != nil {
panic("illegal use of builtin in go statement")
}
fn = fr.indirectFunction(fn, args)
fr.createCall(fr.runtime.Go, []*LLVMValue{fn})
case *ssa.If:
cond := fr.value(instr.Cond).LLVMValue()
block := instr.Block()
trueBlock := fr.block(block.Succs[0])
falseBlock := fr.block(block.Succs[1])
fr.builder.CreateCondBr(cond, trueBlock, falseBlock)
case *ssa.Index:
// FIXME Surely we should be dealing with an
// *array, so we can do a GEP?
array := fr.value(instr.X).LLVMValue()
arrayptr := fr.builder.CreateAlloca(array.Type(), "")
fr.builder.CreateStore(array, arrayptr)
index := fr.value(instr.Index).LLVMValue()
zero := llvm.ConstNull(index.Type())
addr := fr.builder.CreateGEP(arrayptr, []llvm.Value{zero, index}, "")
fr.env[instr] = fr.NewValue(fr.builder.CreateLoad(addr, ""), instr.Type())
case *ssa.IndexAddr:
// TODO: implement nil-check and panic.
// TODO: combine a chain of {Field,Index}Addrs into a single GEP.
x := fr.value(instr.X).LLVMValue()
index := fr.value(instr.Index).LLVMValue()
var addr llvm.Value
var elemtyp types.Type
zero := llvm.ConstNull(index.Type())
switch typ := instr.X.Type().Underlying().(type) {
case *types.Slice:
elemtyp = typ.Elem()
x = fr.builder.CreateExtractValue(x, 0, "")
addr = fr.builder.CreateGEP(x, []llvm.Value{index}, "")
case *types.Pointer: // *array
elemtyp = typ.Elem().Underlying().(*types.Array).Elem()
addr = fr.builder.CreateGEP(x, []llvm.Value{zero, index}, "")
}
fr.env[instr] = fr.NewValue(addr, types.NewPointer(elemtyp))
case *ssa.Jump:
succ := instr.Block().Succs[0]
fr.builder.CreateBr(fr.block(succ))
case *ssa.Lookup:
x := fr.value(instr.X)
index := fr.value(instr.Index)
if isString(x.Type().Underlying()) {
fr.env[instr] = fr.stringIndex(x, index)
} else {
fr.env[instr] = fr.mapLookup(x, index, instr.CommaOk)
}
case *ssa.MakeChan:
fr.env[instr] = fr.makeChan(instr.Type(), fr.value(instr.Size))
case *ssa.MakeClosure:
fn := fr.resolveFunction(instr.Fn.(*ssa.Function))
bindings := make([]*LLVMValue, len(instr.Bindings))
for i, binding := range instr.Bindings {
bindings[i] = fr.value(binding)
}
fr.env[instr] = fr.makeClosure(fn, bindings)
case *ssa.MakeInterface:
receiver := fr.value(instr.X)
fr.env[instr] = fr.makeInterface(receiver, instr.Type())
case *ssa.MakeMap:
fr.env[instr] = fr.makeMap(instr.Type(), fr.value(instr.Reserve))
case *ssa.MakeSlice:
length := fr.value(instr.Len)
capacity := fr.value(instr.Cap)
fr.env[instr] = fr.makeSlice(instr.Type(), length, capacity)
case *ssa.MapUpdate:
m := fr.value(instr.Map)
k := fr.value(instr.Key)
v := fr.value(instr.Value)
fr.mapUpdate(m, k, v)
case *ssa.Next:
iter := fr.value(instr.Iter)
if !instr.IsString {
fr.env[instr] = fr.mapIterNext(iter)
return
}
// String range
//
// We make some assumptions for now around the
// current state of affairs in go.tools/ssa.
//
// - Range's block is a predecessor of Next's.
// (this is currently true, but may change in the future;
// adonovan says he will expose the dominator tree
// computation in the future, which we can use here).
// - Next is the first non-Phi instruction in its block.
// (this is not strictly necessary; we can move the Phi
// to the top of the block, and defer the tuple creation
// to Extract).
assert(instr.Iter.(*ssa.Range).Block() == instr.Block().Preds[0])
for _, blockInstr := range instr.Block().Instrs {
if instr == blockInstr {
break
}
_, isphi := blockInstr.(*ssa.Phi)
assert(isphi)
}
preds := instr.Block().Preds
llpreds := make([]llvm.BasicBlock, len(preds))
for i, b := range preds {
llpreds[i] = fr.block(b)
}
fr.env[instr] = fr.stringIterNext(iter, llpreds)
case *ssa.Panic:
arg := fr.value(instr.X).LLVMValue()
fr.builder.CreateCall(fr.runtime.panic_.LLVMValue(), []llvm.Value{arg}, "")
fr.builder.CreateUnreachable()
case *ssa.Phi:
typ := instr.Type()
phi := fr.builder.CreatePHI(fr.llvmtypes.ToLLVM(typ), instr.Comment)
fr.env[instr] = fr.NewValue(phi, typ)
values := make([]llvm.Value, len(instr.Edges))
blocks := make([]llvm.BasicBlock, len(instr.Edges))
block := instr.Block()
for i, edge := range instr.Edges {
values[i] = fr.value(edge).LLVMValue()
blocks[i] = fr.block(block.Preds[i])
}
phi.AddIncoming(values, blocks)
case *ssa.Range:
x := fr.value(instr.X)
switch x.Type().Underlying().(type) {
case *types.Map:
fr.env[instr] = fr.mapIterInit(x)
case *types.Basic: // string
fr.env[instr] = x
default:
panic(fmt.Sprintf("unhandled range for type %T", x.Type()))
}
case *ssa.Return:
switch n := len(instr.Results); n {
case 0:
// https://code.google.com/p/go/issues/detail?id=7022
if r := instr.Parent().Signature.Results(); r != nil && r.Len() > 0 {
fr.builder.CreateUnreachable()
} else {
fr.builder.CreateRetVoid()
}
case 1:
fr.builder.CreateRet(fr.value(instr.Results[0]).LLVMValue())
default:
values := make([]llvm.Value, n)
for i, result := range instr.Results {
values[i] = fr.value(result).LLVMValue()
}
fr.builder.CreateAggregateRet(values)
}
case *ssa.RunDefers:
fr.builder.CreateCall(fr.runtime.rundefers.LLVMValue(), nil, "")
case *ssa.Select:
states := make([]selectState, len(instr.States))
for i, state := range instr.States {
states[i] = selectState{
Dir: state.Dir,
Chan: fr.value(state.Chan),
Send: fr.value(state.Send),
}
}
fr.env[instr] = fr.chanSelect(states, instr.Blocking)
case *ssa.Send:
fr.chanSend(fr.value(instr.Chan), fr.value(instr.X))
case *ssa.Slice:
x := fr.value(instr.X)
low := fr.value(instr.Low)
high := fr.value(instr.High)
fr.env[instr] = fr.slice(x, low, high)
case *ssa.Store:
addr := fr.value(instr.Addr).LLVMValue()
value := fr.value(instr.Val).LLVMValue()
// The bitcast is necessary to handle recursive pointer stores.
addr = fr.builder.CreateBitCast(addr, llvm.PointerType(value.Type(), 0), "")
fr.builder.CreateStore(value, addr)
case *ssa.TypeAssert:
x := fr.value(instr.X)
if iface, ok := x.Type().Underlying().(*types.Interface); ok && iface.NumMethods() > 0 {
x = x.convertI2E()
}
if !instr.CommaOk {
if _, ok := instr.AssertedType.Underlying().(*types.Interface); ok {
fr.env[instr] = x.mustConvertE2I(instr.AssertedType)
} else {
fr.env[instr] = x.mustConvertE2V(instr.AssertedType)
}
} else {
var result, success *LLVMValue
if _, ok := instr.AssertedType.Underlying().(*types.Interface); ok {
result, success = x.convertE2I(instr.AssertedType)
} else {
result, success = x.convertE2V(instr.AssertedType)
}
resultval := result.LLVMValue()
okval := success.LLVMValue()
pairtyp := llvm.StructType([]llvm.Type{resultval.Type(), okval.Type()}, false)
pair := llvm.Undef(pairtyp)
pair = fr.builder.CreateInsertValue(pair, resultval, 0, "")
pair = fr.builder.CreateInsertValue(pair, okval, 1, "")
fr.env[instr] = fr.NewValue(pair, instr.Type())
}
case *ssa.UnOp:
operand := fr.value(instr.X)
switch instr.Op {
case token.ARROW:
fr.env[instr] = fr.chanRecv(operand, instr.CommaOk)
case token.MUL:
// The bitcast is necessary to handle recursive pointer loads.
llptr := fr.builder.CreateBitCast(operand.LLVMValue(), llvm.PointerType(fr.llvmtypes.ToLLVM(instr.Type()), 0), "")
fr.env[instr] = fr.NewValue(fr.builder.CreateLoad(llptr, ""), instr.Type())
default:
fr.env[instr] = operand.UnaryOp(instr.Op).(*LLVMValue)
}
default:
panic(fmt.Sprintf("unhandled: %v", instr))
}
}