blob: f589db419903ccff3a4861d914f9b7ecb650f633 [file] [log] [blame] [edit]
// Copyright 2020 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 ssa
import (
"cmd/compile/internal/abi"
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/compile/internal/types"
"cmd/internal/src"
"fmt"
)
func postExpandCallsDecompose(f *Func) {
decomposeUser(f) // redo user decompose to cleanup after expand calls
decomposeBuiltIn(f) // handles both regular decomposition and cleanup.
}
func expandCalls(f *Func) {
// Convert each aggregate arg to a call into "dismantle aggregate, store/pass parts"
// Convert each aggregate result from a call into "assemble aggregate from parts"
// Convert each multivalue exit into "dismantle aggregate, store/return parts"
// Convert incoming aggregate arg into assembly of parts.
// Feed modified AST to decompose.
sp, _ := f.spSb()
x := &expandState{
f: f,
debug: f.pass.debug,
regSize: f.Config.RegSize,
sp: sp,
typs: &f.Config.Types,
wideSelects: make(map[*Value]*Value),
commonArgs: make(map[selKey]*Value),
commonSelectors: make(map[selKey]*Value),
memForCall: make(map[ID]*Value),
}
// For 32-bit, need to deal with decomposition of 64-bit integers, which depends on endianness.
if f.Config.BigEndian {
x.firstOp = OpInt64Hi
x.secondOp = OpInt64Lo
x.firstType = x.typs.Int32
x.secondType = x.typs.UInt32
} else {
x.firstOp = OpInt64Lo
x.secondOp = OpInt64Hi
x.firstType = x.typs.UInt32
x.secondType = x.typs.Int32
}
// Defer select processing until after all calls and selects are seen.
var selects []*Value
var calls []*Value
var args []*Value
var exitBlocks []*Block
var m0 *Value
// Accumulate lists of calls, args, selects, and exit blocks to process,
// note "wide" selects consumed by stores,
// rewrite mem for each call,
// rewrite each OpSelectNAddr.
for _, b := range f.Blocks {
for _, v := range b.Values {
switch v.Op {
case OpInitMem:
m0 = v
case OpClosureLECall, OpInterLECall, OpStaticLECall, OpTailLECall:
calls = append(calls, v)
case OpArg:
args = append(args, v)
case OpStore:
if a := v.Args[1]; a.Op == OpSelectN && !CanSSA(a.Type) {
if a.Uses > 1 {
panic(fmt.Errorf("Saw double use of wide SelectN %s operand of Store %s",
a.LongString(), v.LongString()))
}
x.wideSelects[a] = v
}
case OpSelectN:
if v.Type == types.TypeMem {
// rewrite the mem selector in place
call := v.Args[0]
aux := call.Aux.(*AuxCall)
mem := x.memForCall[call.ID]
if mem == nil {
v.AuxInt = int64(aux.abiInfo.OutRegistersUsed())
x.memForCall[call.ID] = v
} else {
panic(fmt.Errorf("Saw two memories for call %v, %v and %v", call, mem, v))
}
} else {
selects = append(selects, v)
}
case OpSelectNAddr:
call := v.Args[0]
which := v.AuxInt
aux := call.Aux.(*AuxCall)
pt := v.Type
off := x.offsetFrom(x.f.Entry, x.sp, aux.OffsetOfResult(which), pt)
v.copyOf(off)
}
}
// rewrite function results from an exit block
// values returned by function need to be split out into registers.
if isBlockMultiValueExit(b) {
exitBlocks = append(exitBlocks, b)
}
}
// Convert each aggregate arg into Make of its parts (and so on, to primitive types)
for _, v := range args {
var rc registerCursor
a := x.prAssignForArg(v)
aux := x.f.OwnAux
regs := a.Registers
var offset int64
if len(regs) == 0 {
offset = a.FrameOffset(aux.abiInfo)
}
auxBase := x.offsetFrom(x.f.Entry, x.sp, offset, types.NewPtr(v.Type))
rc.init(regs, aux.abiInfo, nil, auxBase, 0)
x.rewriteSelectOrArg(f.Entry.Pos, f.Entry, v, v, m0, v.Type, rc)
}
// Rewrite selects of results (which may be aggregates) into make-aggregates of register/memory-targeted selects
for _, v := range selects {
if v.Op == OpInvalid {
continue
}
call := v.Args[0]
aux := call.Aux.(*AuxCall)
mem := x.memForCall[call.ID]
if mem == nil {
mem = call.Block.NewValue1I(call.Pos, OpSelectN, types.TypeMem, int64(aux.abiInfo.OutRegistersUsed()), call)
x.memForCall[call.ID] = mem
}
i := v.AuxInt
regs := aux.RegsOfResult(i)
// If this select cannot fit into SSA and is stored, either disaggregate to register stores, or mem-mem move.
if store := x.wideSelects[v]; store != nil {
// Use the mem that comes from the store operation.
storeAddr := store.Args[0]
mem := store.Args[2]
if len(regs) > 0 {
// Cannot do a rewrite that builds up a result from pieces; instead, copy pieces to the store operation.
var rc registerCursor
rc.init(regs, aux.abiInfo, nil, storeAddr, 0)
mem = x.rewriteWideSelectToStores(call.Pos, call.Block, v, mem, v.Type, rc)
store.copyOf(mem)
} else {
// Move directly from AuxBase to store target; rewrite the store instruction.
offset := aux.OffsetOfResult(i)
auxBase := x.offsetFrom(x.f.Entry, x.sp, offset, types.NewPtr(v.Type))
// was Store dst, v, mem
// now Move dst, auxBase, mem
move := store.Block.NewValue3A(store.Pos, OpMove, types.TypeMem, v.Type, storeAddr, auxBase, mem)
move.AuxInt = v.Type.Size()
store.copyOf(move)
}
continue
}
var auxBase *Value
if len(regs) == 0 {
offset := aux.OffsetOfResult(i)
auxBase = x.offsetFrom(x.f.Entry, x.sp, offset, types.NewPtr(v.Type))
}
var rc registerCursor
rc.init(regs, aux.abiInfo, nil, auxBase, 0)
x.rewriteSelectOrArg(call.Pos, call.Block, v, v, mem, v.Type, rc)
}
rewriteCall := func(v *Value, newOp Op, argStart int) {
// Break aggregate args passed to call into smaller pieces.
x.rewriteCallArgs(v, argStart)
v.Op = newOp
rts := abi.RegisterTypes(v.Aux.(*AuxCall).abiInfo.OutParams())
v.Type = types.NewResults(append(rts, types.TypeMem))
}
// Rewrite calls
for _, v := range calls {
switch v.Op {
case OpStaticLECall:
rewriteCall(v, OpStaticCall, 0)
case OpTailLECall:
rewriteCall(v, OpTailCall, 0)
case OpClosureLECall:
rewriteCall(v, OpClosureCall, 2)
case OpInterLECall:
rewriteCall(v, OpInterCall, 1)
}
}
// Rewrite results from exit blocks
for _, b := range exitBlocks {
v := b.Controls[0]
x.rewriteFuncResults(v, b, f.OwnAux)
b.SetControl(v)
}
}
func (x *expandState) rewriteFuncResults(v *Value, b *Block, aux *AuxCall) {
// This is very similar to rewriteCallArgs
// differences:
// firstArg + preArgs
// sp vs auxBase
m0 := v.MemoryArg()
mem := m0
allResults := []*Value{}
var oldArgs []*Value
argsWithoutMem := v.Args[:len(v.Args)-1]
for j, a := range argsWithoutMem {
oldArgs = append(oldArgs, a)
i := int64(j)
auxType := aux.TypeOfResult(i)
auxBase := b.NewValue2A(v.Pos, OpLocalAddr, types.NewPtr(auxType), aux.NameOfResult(i), x.sp, mem)
auxOffset := int64(0)
aRegs := aux.RegsOfResult(int64(j))
if a.Op == OpDereference {
a.Op = OpLoad
}
var rc registerCursor
var result *[]*Value
if len(aRegs) > 0 {
result = &allResults
} else {
if a.Op == OpLoad && a.Args[0].Op == OpLocalAddr {
addr := a.Args[0]
if addr.MemoryArg() == a.MemoryArg() && addr.Aux == aux.NameOfResult(i) {
continue // Self move to output parameter
}
}
}
rc.init(aRegs, aux.abiInfo, result, auxBase, auxOffset)
mem = x.decomposeAsNecessary(v.Pos, b, a, mem, rc)
}
v.resetArgs()
v.AddArgs(allResults...)
v.AddArg(mem)
for _, a := range oldArgs {
if a.Uses == 0 {
if x.debug > 1 {
x.Printf("...marking %v unused\n", a.LongString())
}
x.invalidateRecursively(a)
}
}
v.Type = types.NewResults(append(abi.RegisterTypes(aux.abiInfo.OutParams()), types.TypeMem))
return
}
func (x *expandState) rewriteCallArgs(v *Value, firstArg int) {
if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
x.Printf("rewriteCallArgs(%s; %d)\n", v.LongString(), firstArg)
}
// Thread the stores on the memory arg
aux := v.Aux.(*AuxCall)
m0 := v.MemoryArg()
mem := m0
allResults := []*Value{}
oldArgs := []*Value{}
argsWithoutMem := v.Args[firstArg : len(v.Args)-1] // Also strip closure/interface Op-specific args
sp := x.sp
if v.Op == OpTailLECall {
// For tail call, we unwind the frame before the call so we'll use the caller's
// SP.
sp = x.f.Entry.NewValue1(src.NoXPos, OpGetCallerSP, x.typs.Uintptr, mem)
}
for i, a := range argsWithoutMem { // skip leading non-parameter SSA Args and trailing mem SSA Arg.
oldArgs = append(oldArgs, a)
auxI := int64(i)
aRegs := aux.RegsOfArg(auxI)
aType := aux.TypeOfArg(auxI)
if a.Op == OpDereference {
a.Op = OpLoad
}
var rc registerCursor
var result *[]*Value
var aOffset int64
if len(aRegs) > 0 {
result = &allResults
} else {
aOffset = aux.OffsetOfArg(auxI)
}
if v.Op == OpTailLECall && a.Op == OpArg && a.AuxInt == 0 {
// It's common for a tail call passing the same arguments (e.g. method wrapper),
// so this would be a self copy. Detect this and optimize it out.
n := a.Aux.(*ir.Name)
if n.Class == ir.PPARAM && n.FrameOffset()+x.f.Config.ctxt.Arch.FixedFrameSize == aOffset {
continue
}
}
if x.debug > 1 {
x.Printf("...storeArg %s, %v, %d\n", a.LongString(), aType, aOffset)
}
rc.init(aRegs, aux.abiInfo, result, sp, aOffset)
mem = x.decomposeAsNecessary(v.Pos, v.Block, a, mem, rc)
}
var preArgStore [2]*Value
preArgs := append(preArgStore[:0], v.Args[0:firstArg]...)
v.resetArgs()
v.AddArgs(preArgs...)
v.AddArgs(allResults...)
v.AddArg(mem)
for _, a := range oldArgs {
if a.Uses == 0 {
x.invalidateRecursively(a)
}
}
return
}
func (x *expandState) decomposePair(pos src.XPos, b *Block, a, mem *Value, t0, t1 *types.Type, o0, o1 Op, rc *registerCursor) *Value {
e := b.NewValue1(pos, o0, t0, a)
pos = pos.WithNotStmt()
mem = x.decomposeAsNecessary(pos, b, e, mem, rc.next(t0))
e = b.NewValue1(pos, o1, t1, a)
mem = x.decomposeAsNecessary(pos, b, e, mem, rc.next(t1))
return mem
}
func (x *expandState) decomposeOne(pos src.XPos, b *Block, a, mem *Value, t0 *types.Type, o0 Op, rc *registerCursor) *Value {
e := b.NewValue1(pos, o0, t0, a)
pos = pos.WithNotStmt()
mem = x.decomposeAsNecessary(pos, b, e, mem, rc.next(t0))
return mem
}
// decomposeAsNecessary converts a value (perhaps an aggregate) passed to a call or returned by a function,
// into the appropriate sequence of stores and register assignments to transmit that value in a given ABI, and
// returns the current memory after this convert/rewrite (it may be the input memory, perhaps stores were needed.)
// 'pos' is the source position all this is tied to
// 'b' is the enclosing block
// 'a' is the value to decompose
// 'm0' is the input memory arg used for the first store (or returned if there are no stores)
// 'rc' is a registerCursor which identifies the register/memory destination for the value
func (x *expandState) decomposeAsNecessary(pos src.XPos, b *Block, a, m0 *Value, rc registerCursor) *Value {
if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
}
at := a.Type
if at.Size() == 0 {
return m0
}
if a.Op == OpDereference {
a.Op = OpLoad // For purposes of parameter passing expansion, a Dereference is a Load.
}
if !rc.hasRegs() && !CanSSA(at) {
dst := x.offsetFrom(b, rc.storeDest, rc.storeOffset, types.NewPtr(at))
if x.debug > 1 {
x.Printf("...recur store %s at %s\n", a.LongString(), dst.LongString())
}
if a.Op == OpLoad {
m0 = b.NewValue3A(pos, OpMove, types.TypeMem, at, dst, a.Args[0], m0)
m0.AuxInt = at.Size()
return m0
} else {
panic(fmt.Errorf("Store of not a load"))
}
}
mem := m0
switch at.Kind() {
case types.TARRAY:
et := at.Elem()
for i := int64(0); i < at.NumElem(); i++ {
e := b.NewValue1I(pos, OpArraySelect, et, i, a)
pos = pos.WithNotStmt()
mem = x.decomposeAsNecessary(pos, b, e, mem, rc.next(et))
}
return mem
case types.TSTRUCT:
for i := 0; i < at.NumFields(); i++ {
et := at.Field(i).Type // might need to read offsets from the fields
e := b.NewValue1I(pos, OpStructSelect, et, int64(i), a)
pos = pos.WithNotStmt()
if x.debug > 1 {
x.Printf("...recur decompose %s, %v\n", e.LongString(), et)
}
mem = x.decomposeAsNecessary(pos, b, e, mem, rc.next(et))
}
return mem
case types.TSLICE:
mem = x.decomposeOne(pos, b, a, mem, at.Elem().PtrTo(), OpSlicePtr, &rc)
pos = pos.WithNotStmt()
mem = x.decomposeOne(pos, b, a, mem, x.typs.Int, OpSliceLen, &rc)
return x.decomposeOne(pos, b, a, mem, x.typs.Int, OpSliceCap, &rc)
case types.TSTRING:
return x.decomposePair(pos, b, a, mem, x.typs.BytePtr, x.typs.Int, OpStringPtr, OpStringLen, &rc)
case types.TINTER:
mem = x.decomposeOne(pos, b, a, mem, x.typs.Uintptr, OpITab, &rc)
pos = pos.WithNotStmt()
// Immediate interfaces cause so many headaches.
if a.Op == OpIMake {
data := a.Args[1]
for data.Op == OpStructMake || data.Op == OpArrayMake1 {
data = data.Args[0]
}
return x.decomposeAsNecessary(pos, b, data, mem, rc.next(data.Type))
}
return x.decomposeOne(pos, b, a, mem, x.typs.BytePtr, OpIData, &rc)
case types.TCOMPLEX64:
return x.decomposePair(pos, b, a, mem, x.typs.Float32, x.typs.Float32, OpComplexReal, OpComplexImag, &rc)
case types.TCOMPLEX128:
return x.decomposePair(pos, b, a, mem, x.typs.Float64, x.typs.Float64, OpComplexReal, OpComplexImag, &rc)
case types.TINT64:
if at.Size() > x.regSize {
return x.decomposePair(pos, b, a, mem, x.firstType, x.secondType, x.firstOp, x.secondOp, &rc)
}
case types.TUINT64:
if at.Size() > x.regSize {
return x.decomposePair(pos, b, a, mem, x.typs.UInt32, x.typs.UInt32, x.firstOp, x.secondOp, &rc)
}
}
// An atomic type, either record the register or store it and update the memory.
if rc.hasRegs() {
if x.debug > 1 {
x.Printf("...recur addArg %s\n", a.LongString())
}
rc.addArg(a)
} else {
dst := x.offsetFrom(b, rc.storeDest, rc.storeOffset, types.NewPtr(at))
if x.debug > 1 {
x.Printf("...recur store %s at %s\n", a.LongString(), dst.LongString())
}
mem = b.NewValue3A(pos, OpStore, types.TypeMem, at, dst, a, mem)
}
return mem
}
// Convert scalar OpArg into the proper OpWhateverArg instruction
// Convert scalar OpSelectN into perhaps-differently-indexed OpSelectN
// Convert aggregate OpArg into Make of its parts (which are eventually scalars)
// Convert aggregate OpSelectN into Make of its parts (which are eventually scalars)
// Returns the converted value.
//
// - "pos" the position for any generated instructions
// - "b" the block for any generated instructions
// - "container" the outermost OpArg/OpSelectN
// - "a" the instruction to overwrite, if any (only the outermost caller)
// - "m0" the memory arg for any loads that are necessary
// - "at" the type of the Arg/part
// - "rc" the register/memory cursor locating the various parts of the Arg.
func (x *expandState) rewriteSelectOrArg(pos src.XPos, b *Block, container, a, m0 *Value, at *types.Type, rc registerCursor) *Value {
if at == types.TypeMem {
a.copyOf(m0)
return a
}
makeOf := func(a *Value, op Op, args []*Value) *Value {
if a == nil {
a = b.NewValue0(pos, op, at)
a.AddArgs(args...)
} else {
a.resetArgs()
a.Aux, a.AuxInt = nil, 0
a.Pos, a.Op, a.Type = pos, op, at
a.AddArgs(args...)
}
return a
}
if at.Size() == 0 {
// For consistency, create these values even though they'll ultimately be unused
if at.IsArray() {
return makeOf(a, OpArrayMake0, nil)
}
if at.IsStruct() {
return makeOf(a, OpStructMake, nil)
}
return a
}
sk := selKey{from: container, size: 0, offsetOrIndex: rc.storeOffset, typ: at}
dupe := x.commonSelectors[sk]
if dupe != nil {
if a == nil {
return dupe
}
a.copyOf(dupe)
return a
}
var argStore [10]*Value
args := argStore[:0]
addArg := func(a0 *Value) {
if a0 == nil {
as := "<nil>"
if a != nil {
as = a.LongString()
}
panic(fmt.Errorf("a0 should not be nil, a=%v, container=%v, at=%v", as, container.LongString(), at))
}
args = append(args, a0)
}
switch at.Kind() {
case types.TARRAY:
et := at.Elem()
for i := int64(0); i < at.NumElem(); i++ {
e := x.rewriteSelectOrArg(pos, b, container, nil, m0, et, rc.next(et))
addArg(e)
}
a = makeOf(a, OpArrayMake1, args)
x.commonSelectors[sk] = a
return a
case types.TSTRUCT:
// Assume ssagen/ssa.go (in buildssa) spills large aggregates so they won't appear here.
for i := 0; i < at.NumFields(); i++ {
et := at.Field(i).Type
e := x.rewriteSelectOrArg(pos, b, container, nil, m0, et, rc.next(et))
if e == nil {
panic(fmt.Errorf("nil e, et=%v, et.Size()=%d, i=%d", et, et.Size(), i))
}
addArg(e)
pos = pos.WithNotStmt()
}
if at.NumFields() > 4 {
panic(fmt.Errorf("Too many fields (%d, %d bytes), container=%s", at.NumFields(), at.Size(), container.LongString()))
}
a = makeOf(a, OpStructMake, args)
x.commonSelectors[sk] = a
return a
case types.TSLICE:
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, at.Elem().PtrTo(), rc.next(x.typs.BytePtr)))
pos = pos.WithNotStmt()
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Int, rc.next(x.typs.Int)))
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Int, rc.next(x.typs.Int)))
a = makeOf(a, OpSliceMake, args)
x.commonSelectors[sk] = a
return a
case types.TSTRING:
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.BytePtr, rc.next(x.typs.BytePtr)))
pos = pos.WithNotStmt()
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Int, rc.next(x.typs.Int)))
a = makeOf(a, OpStringMake, args)
x.commonSelectors[sk] = a
return a
case types.TINTER:
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Uintptr, rc.next(x.typs.Uintptr)))
pos = pos.WithNotStmt()
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.BytePtr, rc.next(x.typs.BytePtr)))
a = makeOf(a, OpIMake, args)
x.commonSelectors[sk] = a
return a
case types.TCOMPLEX64:
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Float32, rc.next(x.typs.Float32)))
pos = pos.WithNotStmt()
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Float32, rc.next(x.typs.Float32)))
a = makeOf(a, OpComplexMake, args)
x.commonSelectors[sk] = a
return a
case types.TCOMPLEX128:
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Float64, rc.next(x.typs.Float64)))
pos = pos.WithNotStmt()
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.Float64, rc.next(x.typs.Float64)))
a = makeOf(a, OpComplexMake, args)
x.commonSelectors[sk] = a
return a
case types.TINT64:
if at.Size() > x.regSize {
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.firstType, rc.next(x.firstType)))
pos = pos.WithNotStmt()
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.secondType, rc.next(x.secondType)))
if !x.f.Config.BigEndian {
// Int64Make args are big, little
args[0], args[1] = args[1], args[0]
}
a = makeOf(a, OpInt64Make, args)
x.commonSelectors[sk] = a
return a
}
case types.TUINT64:
if at.Size() > x.regSize {
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.UInt32, rc.next(x.typs.UInt32)))
pos = pos.WithNotStmt()
addArg(x.rewriteSelectOrArg(pos, b, container, nil, m0, x.typs.UInt32, rc.next(x.typs.UInt32)))
if !x.f.Config.BigEndian {
// Int64Make args are big, little
args[0], args[1] = args[1], args[0]
}
a = makeOf(a, OpInt64Make, args)
x.commonSelectors[sk] = a
return a
}
}
// An atomic type, either record the register or store it and update the memory.
// Depending on the container Op, the leaves are either OpSelectN or OpArg{Int,Float}Reg
if container.Op == OpArg {
if rc.hasRegs() {
op, i := rc.ArgOpAndRegisterFor()
name := container.Aux.(*ir.Name)
a = makeOf(a, op, nil)
a.AuxInt = i
a.Aux = &AuxNameOffset{name, rc.storeOffset}
} else {
key := selKey{container, rc.storeOffset, at.Size(), at}
w := x.commonArgs[key]
if w != nil && w.Uses != 0 {
if a == nil {
a = w
} else {
a.copyOf(w)
}
} else {
if a == nil {
aux := container.Aux
auxInt := container.AuxInt + rc.storeOffset
a = container.Block.NewValue0IA(container.Pos, OpArg, at, auxInt, aux)
} else {
// do nothing, the original should be okay.
}
x.commonArgs[key] = a
}
}
} else if container.Op == OpSelectN {
call := container.Args[0]
aux := call.Aux.(*AuxCall)
which := container.AuxInt
if at == types.TypeMem {
if a != m0 || a != x.memForCall[call.ID] {
panic(fmt.Errorf("Memories %s, %s, and %s should all be equal after %s", a.LongString(), m0.LongString(), x.memForCall[call.ID], call.LongString()))
}
} else if rc.hasRegs() {
firstReg := uint32(0)
for i := 0; i < int(which); i++ {
firstReg += uint32(len(aux.abiInfo.OutParam(i).Registers))
}
reg := int64(rc.nextSlice + Abi1RO(firstReg))
a = makeOf(a, OpSelectN, []*Value{call})
a.AuxInt = reg
} else {
off := x.offsetFrom(x.f.Entry, x.sp, rc.storeOffset+aux.OffsetOfResult(which), types.NewPtr(at))
a = makeOf(a, OpLoad, []*Value{off, m0})
}
} else {
panic(fmt.Errorf("Expected container OpArg or OpSelectN, saw %v instead", container.LongString()))
}
x.commonSelectors[sk] = a
return a
}
// rewriteWideSelectToStores handles the case of a SelectN'd result from a function call that is too large for SSA,
// but is transferred in registers. In this case the register cursor tracks both operands; the register sources and
// the memory destinations.
// This returns the memory flowing out of the last store
func (x *expandState) rewriteWideSelectToStores(pos src.XPos, b *Block, container, m0 *Value, at *types.Type, rc registerCursor) *Value {
if at.Size() == 0 {
return m0
}
switch at.Kind() {
case types.TARRAY:
et := at.Elem()
for i := int64(0); i < at.NumElem(); i++ {
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, et, rc.next(et))
}
return m0
case types.TSTRUCT:
// Assume ssagen/ssa.go (in buildssa) spills large aggregates so they won't appear here.
for i := 0; i < at.NumFields(); i++ {
et := at.Field(i).Type
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, et, rc.next(et))
pos = pos.WithNotStmt()
}
return m0
case types.TSLICE:
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, at.Elem().PtrTo(), rc.next(x.typs.BytePtr))
pos = pos.WithNotStmt()
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Int, rc.next(x.typs.Int))
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Int, rc.next(x.typs.Int))
return m0
case types.TSTRING:
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.BytePtr, rc.next(x.typs.BytePtr))
pos = pos.WithNotStmt()
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Int, rc.next(x.typs.Int))
return m0
case types.TINTER:
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Uintptr, rc.next(x.typs.Uintptr))
pos = pos.WithNotStmt()
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.BytePtr, rc.next(x.typs.BytePtr))
return m0
case types.TCOMPLEX64:
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Float32, rc.next(x.typs.Float32))
pos = pos.WithNotStmt()
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Float32, rc.next(x.typs.Float32))
return m0
case types.TCOMPLEX128:
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Float64, rc.next(x.typs.Float64))
pos = pos.WithNotStmt()
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.Float64, rc.next(x.typs.Float64))
return m0
case types.TINT64:
if at.Size() > x.regSize {
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.firstType, rc.next(x.firstType))
pos = pos.WithNotStmt()
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.secondType, rc.next(x.secondType))
return m0
}
case types.TUINT64:
if at.Size() > x.regSize {
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.UInt32, rc.next(x.typs.UInt32))
pos = pos.WithNotStmt()
m0 = x.rewriteWideSelectToStores(pos, b, container, m0, x.typs.UInt32, rc.next(x.typs.UInt32))
return m0
}
}
// TODO could change treatment of too-large OpArg, would deal with it here.
if container.Op == OpSelectN {
call := container.Args[0]
aux := call.Aux.(*AuxCall)
which := container.AuxInt
if rc.hasRegs() {
firstReg := uint32(0)
for i := 0; i < int(which); i++ {
firstReg += uint32(len(aux.abiInfo.OutParam(i).Registers))
}
reg := int64(rc.nextSlice + Abi1RO(firstReg))
a := b.NewValue1I(pos, OpSelectN, at, reg, call)
dst := x.offsetFrom(b, rc.storeDest, rc.storeOffset, types.NewPtr(at))
m0 = b.NewValue3A(pos, OpStore, types.TypeMem, at, dst, a, m0)
} else {
panic(fmt.Errorf("Expected rc to have registers"))
}
} else {
panic(fmt.Errorf("Expected container OpSelectN, saw %v instead", container.LongString()))
}
return m0
}
func isBlockMultiValueExit(b *Block) bool {
return (b.Kind == BlockRet || b.Kind == BlockRetJmp) && b.Controls[0] != nil && b.Controls[0].Op == OpMakeResult
}
type Abi1RO uint8 // An offset within a parameter's slice of register indices, for abi1.
// A registerCursor tracks which register is used for an Arg or regValues, or a piece of such.
type registerCursor struct {
storeDest *Value // if there are no register targets, then this is the base of the store.
storeOffset int64
regs []abi.RegIndex // the registers available for this Arg/result (which is all in registers or not at all)
nextSlice Abi1RO // the next register/register-slice offset
config *abi.ABIConfig
regValues *[]*Value // values assigned to registers accumulate here
}
func (c *registerCursor) String() string {
dest := "<none>"
if c.storeDest != nil {
dest = fmt.Sprintf("%s+%d", c.storeDest.String(), c.storeOffset)
}
regs := "<none>"
if c.regValues != nil {
regs = ""
for i, x := range *c.regValues {
if i > 0 {
regs = regs + "; "
}
regs = regs + x.LongString()
}
}
// not printing the config because that has not been useful
return fmt.Sprintf("RCSR{storeDest=%v, regsLen=%d, nextSlice=%d, regValues=[%s]}", dest, len(c.regs), c.nextSlice, regs)
}
// next effectively post-increments the register cursor; the receiver is advanced,
// the (aligned) old value is returned.
func (c *registerCursor) next(t *types.Type) registerCursor {
c.storeOffset = types.RoundUp(c.storeOffset, t.Alignment())
rc := *c
c.storeOffset = types.RoundUp(c.storeOffset+t.Size(), t.Alignment())
if int(c.nextSlice) < len(c.regs) {
w := c.config.NumParamRegs(t)
c.nextSlice += Abi1RO(w)
}
return rc
}
// plus returns a register cursor offset from the original, without modifying the original.
func (c *registerCursor) plus(regWidth Abi1RO) registerCursor {
rc := *c
rc.nextSlice += regWidth
return rc
}
// at returns the register cursor for component i of t, where the first
// component is numbered 0.
func (c *registerCursor) at(t *types.Type, i int) registerCursor {
rc := *c
if i == 0 || len(c.regs) == 0 {
return rc
}
if t.IsArray() {
w := c.config.NumParamRegs(t.Elem())
rc.nextSlice += Abi1RO(i * w)
return rc
}
if t.IsStruct() {
for j := 0; j < i; j++ {
rc.next(t.FieldType(j))
}
return rc
}
panic("Haven't implemented this case yet, do I need to?")
}
func (c *registerCursor) init(regs []abi.RegIndex, info *abi.ABIParamResultInfo, result *[]*Value, storeDest *Value, storeOffset int64) {
c.regs = regs
c.nextSlice = 0
c.storeOffset = storeOffset
c.storeDest = storeDest
c.config = info.Config()
c.regValues = result
}
func (c *registerCursor) addArg(v *Value) {
*c.regValues = append(*c.regValues, v)
}
func (c *registerCursor) hasRegs() bool {
return len(c.regs) > 0
}
func (c *registerCursor) ArgOpAndRegisterFor() (Op, int64) {
r := c.regs[c.nextSlice]
return ArgOpAndRegisterFor(r, c.config)
}
// ArgOpAndRegisterFor converts an abi register index into an ssa Op and corresponding
// arg register index.
func ArgOpAndRegisterFor(r abi.RegIndex, abiConfig *abi.ABIConfig) (Op, int64) {
i := abiConfig.FloatIndexFor(r)
if i >= 0 { // float PR
return OpArgFloatReg, i
}
return OpArgIntReg, int64(r)
}
type selKey struct {
from *Value // what is selected from
offsetOrIndex int64 // whatever is appropriate for the selector
size int64
typ *types.Type
}
type expandState struct {
f *Func
debug int // odd values log lost statement markers, so likely settings are 1 (stmts), 2 (expansion), and 3 (both)
regSize int64
sp *Value
typs *Types
firstOp Op // for 64-bit integers on 32-bit machines, first word in memory
secondOp Op // for 64-bit integers on 32-bit machines, second word in memory
firstType *types.Type // first half type, for Int64
secondType *types.Type // second half type, for Int64
wideSelects map[*Value]*Value // Selects that are not SSA-able, mapped to consuming stores.
commonSelectors map[selKey]*Value // used to de-dupe selectors
commonArgs map[selKey]*Value // used to de-dupe OpArg/OpArgIntReg/OpArgFloatReg
memForCall map[ID]*Value // For a call, need to know the unique selector that gets the mem.
indentLevel int // Indentation for debugging recursion
}
// intPairTypes returns the pair of 32-bit int types needed to encode a 64-bit integer type on a target
// that has no 64-bit integer registers.
func (x *expandState) intPairTypes(et types.Kind) (tHi, tLo *types.Type) {
tHi = x.typs.UInt32
if et == types.TINT64 {
tHi = x.typs.Int32
}
tLo = x.typs.UInt32
return
}
// offsetFrom creates an offset from a pointer, simplifying chained offsets and offsets from SP
func (x *expandState) offsetFrom(b *Block, from *Value, offset int64, pt *types.Type) *Value {
ft := from.Type
if offset == 0 {
if ft == pt {
return from
}
// This captures common, (apparently) safe cases. The unsafe cases involve ft == uintptr
if (ft.IsPtr() || ft.IsUnsafePtr()) && pt.IsPtr() {
return from
}
}
// Simplify, canonicalize
for from.Op == OpOffPtr {
offset += from.AuxInt
from = from.Args[0]
}
if from == x.sp {
return x.f.ConstOffPtrSP(pt, offset, x.sp)
}
return b.NewValue1I(from.Pos.WithNotStmt(), OpOffPtr, pt, offset, from)
}
func (x *expandState) regWidth(t *types.Type) Abi1RO {
return Abi1RO(x.f.ABI1.NumParamRegs(t))
}
// regOffset returns the register offset of the i'th element of type t
func (x *expandState) regOffset(t *types.Type, i int) Abi1RO {
// TODO maybe cache this in a map if profiling recommends.
if i == 0 {
return 0
}
if t.IsArray() {
return Abi1RO(i) * x.regWidth(t.Elem())
}
if t.IsStruct() {
k := Abi1RO(0)
for j := 0; j < i; j++ {
k += x.regWidth(t.FieldType(j))
}
return k
}
panic("Haven't implemented this case yet, do I need to?")
}
// prAssignForArg returns the ABIParamAssignment for v, assumed to be an OpArg.
func (x *expandState) prAssignForArg(v *Value) *abi.ABIParamAssignment {
if v.Op != OpArg {
panic(fmt.Errorf("Wanted OpArg, instead saw %s", v.LongString()))
}
return ParamAssignmentForArgName(x.f, v.Aux.(*ir.Name))
}
// ParamAssignmentForArgName returns the ABIParamAssignment for f's arg with matching name.
func ParamAssignmentForArgName(f *Func, name *ir.Name) *abi.ABIParamAssignment {
abiInfo := f.OwnAux.abiInfo
ip := abiInfo.InParams()
for i, a := range ip {
if a.Name == name {
return &ip[i]
}
}
panic(fmt.Errorf("Did not match param %v in prInfo %+v", name, abiInfo.InParams()))
}
// indent increments (or decrements) the indentation.
func (x *expandState) indent(n int) {
x.indentLevel += n
}
// Printf does an indented fmt.Printf on the format and args.
func (x *expandState) Printf(format string, a ...interface{}) (n int, err error) {
if x.indentLevel > 0 {
fmt.Printf("%[1]*s", x.indentLevel, "")
}
return fmt.Printf(format, a...)
}
func (x *expandState) invalidateRecursively(a *Value) {
var s string
if x.debug > 0 {
plus := " "
if a.Pos.IsStmt() == src.PosIsStmt {
plus = " +"
}
s = a.String() + plus + a.Pos.LineNumber() + " " + a.LongString()
if x.debug > 1 {
x.Printf("...marking %v unused\n", s)
}
}
lost := a.invalidateRecursively()
if x.debug&1 != 0 && lost { // For odd values of x.debug, do this.
x.Printf("Lost statement marker in %s on former %s\n", base.Ctxt.Pkgpath+"."+x.f.Name, s)
}
}