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path: root/src/cmd/compile/internal/ssa/expand_calls.go
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Diffstat (limited to 'src/cmd/compile/internal/ssa/expand_calls.go')
-rw-r--r--src/cmd/compile/internal/ssa/expand_calls.go124
1 files changed, 83 insertions, 41 deletions
diff --git a/src/cmd/compile/internal/ssa/expand_calls.go b/src/cmd/compile/internal/ssa/expand_calls.go
index b37d3b8c9c0..a0f0e653aa4 100644
--- a/src/cmd/compile/internal/ssa/expand_calls.go
+++ b/src/cmd/compile/internal/ssa/expand_calls.go
@@ -176,7 +176,7 @@ func (c *registerCursor) hasRegs() bool {
type expandState struct {
f *Func
abi1 *abi.ABIConfig
- debug bool
+ debug int // odd values log lost statement markers, so likely settings are 1 (stmts), 2 (expansion), and 3 (both)
canSSAType func(*types.Type) bool
regSize int64
sp *Value
@@ -302,7 +302,7 @@ func (x *expandState) Printf(format string, a ...interface{}) (n int, err error)
//
// TODO when registers really arrive, must also decompose anything split across two registers or registers and memory.
func (x *expandState) rewriteSelect(leaf *Value, selector *Value, offset int64, regOffset Abi1RO) []*LocalSlot {
- if x.debug {
+ if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
x.Printf("rewriteSelect(%s; %s; memOff=%d; regOff=%d)\n", leaf.LongString(), selector.LongString(), offset, regOffset)
@@ -325,7 +325,7 @@ func (x *expandState) rewriteSelect(leaf *Value, selector *Value, offset int64,
} else {
x.f.Fatalf("Unexpected %s type, selector=%s, leaf=%s\n", selector.Op.String(), selector.LongString(), leaf.LongString())
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("---%s, break\n", selector.Op.String())
}
case OpArg:
@@ -335,7 +335,7 @@ func (x *expandState) rewriteSelect(leaf *Value, selector *Value, offset int64,
} else {
x.f.Fatalf("Unexpected OpArg type, selector=%s, leaf=%s\n", selector.LongString(), leaf.LongString())
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("---OpArg, break\n")
}
break
@@ -381,7 +381,7 @@ func (x *expandState) rewriteSelect(leaf *Value, selector *Value, offset int64,
// This case removes that StructSelect.
if leafType != selector.Type {
if x.f.Config.SoftFloat && selector.Type.IsFloat() {
- if x.debug {
+ if x.debug > 1 {
x.Printf("---OpLoad, break\n")
}
break // softfloat pass will take care of that
@@ -468,7 +468,7 @@ func (x *expandState) rewriteSelect(leaf *Value, selector *Value, offset int64,
} else {
w := call.Block.NewValue2(leaf.Pos, OpLoad, leafType, off, call)
leaf.copyOf(w)
- if x.debug {
+ if x.debug > 1 {
x.Printf("---new %s\n", w.LongString())
}
}
@@ -687,7 +687,7 @@ func (x *expandState) decomposeArg(pos src.XPos, b *Block, source, mem *Value, t
panic(fmt.Errorf("offset %d of requested register %d should be zero, source=%s", offs[loadRegOffset], loadRegOffset, source.LongString()))
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("decompose arg %s has %d locs\n", source.LongString(), len(locs))
}
@@ -836,7 +836,7 @@ func (x *expandState) decomposeLoad(pos src.XPos, b *Block, source, mem *Value,
// pos and b locate the store instruction, source is the "base" of the value input,
// mem is the input mem, t is the type in question, and offArg and offStore are the offsets from the respective bases.
func storeOneArg(x *expandState, pos src.XPos, b *Block, locs []*LocalSlot, suffix string, source, mem *Value, t *types.Type, argOffset, storeOffset int64, loadRegOffset Abi1RO, storeRc registerCursor) *Value {
- if x.debug {
+ if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
x.Printf("storeOneArg(%s; %s; %s; aO=%d; sO=%d; lrO=%d; %s)\n", source.LongString(), mem.String(), t.String(), argOffset, storeOffset, loadRegOffset, storeRc.String())
@@ -877,7 +877,7 @@ func storeTwoLoad(x *expandState, pos src.XPos, b *Block, source, mem *Value, t1
// stores of non-aggregate types. It recursively walks up a chain of selectors until it reaches a Load or an Arg.
// If it does not reach a Load or an Arg, nothing happens; this allows a little freedom in phase ordering.
func (x *expandState) storeArgOrLoad(pos src.XPos, b *Block, source, mem *Value, t *types.Type, storeOffset int64, loadRegOffset Abi1RO, storeRc registerCursor) *Value {
- if x.debug {
+ if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
x.Printf("storeArgOrLoad(%s; %s; %s; %d; %s)\n", source.LongString(), mem.String(), t.String(), storeOffset, storeRc.String())
@@ -1060,7 +1060,7 @@ func (x *expandState) storeArgOrLoad(pos src.XPos, b *Block, source, mem *Value,
dst := x.offsetFrom(b, storeRc.storeDest, storeOffset, types.NewPtr(t))
s = b.NewValue3A(pos, OpStore, types.TypeMem, t, dst, source, mem)
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("-->storeArg returns %s, storeRc=%s\n", s.LongString(), storeRc.String())
}
return s
@@ -1071,18 +1071,23 @@ func (x *expandState) storeArgOrLoad(pos src.XPos, b *Block, source, mem *Value,
// to account for any parameter stores required.
// Any of the old Args that have their use count fall to zero are marked OpInvalid.
func (x *expandState) rewriteArgs(v *Value, firstArg int) {
- if x.debug {
+ if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
x.Printf("rewriteArgs(%s; %d)\n", v.LongString(), firstArg)
}
// Thread the stores on the memory arg
aux := v.Aux.(*AuxCall)
- pos := v.Pos.WithNotStmt()
m0 := v.MemoryArg()
mem := m0
newArgs := []*Value{}
oldArgs := []*Value{}
+ 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.NewValue0(src.NoXPos, OpGetCallerSP, x.typs.Uintptr)
+ }
for i, a := range v.Args[firstArg : len(v.Args)-1] { // skip leading non-parameter SSA Args and trailing mem SSA Arg.
oldArgs = append(oldArgs, a)
auxI := int64(i)
@@ -1093,9 +1098,20 @@ func (x *expandState) rewriteArgs(v *Value, firstArg int) {
if a.MemoryArg() != m0 {
x.f.Fatalf("Op...LECall and OpDereference have mismatched mem, %s and %s", v.LongString(), a.LongString())
}
+ if v.Op == OpTailLECall {
+ // 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.
+ a0 := a.Args[0]
+ if a0.Op == OpLocalAddr {
+ n := a0.Aux.(*ir.Name)
+ if n.Class == ir.PPARAM && n.FrameOffset()+x.f.Config.ctxt.FixedFrameSize() == aOffset {
+ continue
+ }
+ }
+ }
// "Dereference" of addressed (probably not-SSA-eligible) value becomes Move
// TODO(register args) this will be more complicated with registers in the picture.
- mem = x.rewriteDereference(v.Block, x.sp, a, mem, aOffset, aux.SizeOfArg(auxI), aType, pos)
+ mem = x.rewriteDereference(v.Block, sp, a, mem, aOffset, aux.SizeOfArg(auxI), aType, a.Pos)
} else {
var rc registerCursor
var result *[]*Value
@@ -1105,11 +1121,19 @@ func (x *expandState) rewriteArgs(v *Value, firstArg int) {
} else {
aOffset = aux.OffsetOfArg(auxI)
}
- if x.debug {
+ 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.FixedFrameSize() == aOffset {
+ continue
+ }
+ }
+ if x.debug > 1 {
x.Printf("...storeArg %s, %v, %d\n", a.LongString(), aType, aOffset)
}
- rc.init(aRegs, aux.abiInfo, result, x.sp)
- mem = x.storeArgOrLoad(pos, v.Block, a, mem, aType, aOffset, 0, rc)
+ rc.init(aRegs, aux.abiInfo, result, sp)
+ mem = x.storeArgOrLoad(a.Pos, v.Block, a, mem, aType, aOffset, 0, rc)
}
}
var preArgStore [2]*Value
@@ -1120,16 +1144,31 @@ func (x *expandState) rewriteArgs(v *Value, firstArg int) {
v.AddArg(mem)
for _, a := range oldArgs {
if a.Uses == 0 {
- if x.debug {
- x.Printf("...marking %v unused\n", a.LongString())
- }
- a.invalidateRecursively()
+ x.invalidateRecursively(a)
}
}
return
}
+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)
+ }
+}
+
// expandCalls converts LE (Late Expansion) calls that act like they receive value args into a lower-level form
// that is more oriented to a platform's ABI. The SelectN operations that extract results are rewritten into
// more appropriate forms, and any StructMake or ArrayMake inputs are decomposed until non-struct values are
@@ -1148,7 +1187,7 @@ func expandCalls(f *Func) {
x := &expandState{
f: f,
abi1: f.ABI1,
- debug: f.pass.debug > 0,
+ debug: f.pass.debug,
canSSAType: f.fe.CanSSA,
regSize: f.Config.RegSize,
sp: sp,
@@ -1170,7 +1209,7 @@ func expandCalls(f *Func) {
x.loRo, x.hiRo = 0, 1
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("\nexpandsCalls(%s)\n", f.Name)
}
@@ -1193,7 +1232,7 @@ func expandCalls(f *Func) {
for _, v := range b.Values {
firstArg := 0
switch v.Op {
- case OpStaticLECall:
+ case OpStaticLECall, OpTailLECall:
case OpInterLECall:
firstArg = 1
case OpClosureLECall:
@@ -1210,9 +1249,8 @@ func expandCalls(f *Func) {
m0 := v.MemoryArg()
mem := m0
aux := f.OwnAux
- pos := v.Pos.WithNotStmt()
allResults := []*Value{}
- if x.debug {
+ if x.debug > 1 {
x.Printf("multiValueExit rewriting %s\n", v.LongString())
}
var oldArgs []*Value
@@ -1233,7 +1271,7 @@ func expandCalls(f *Func) {
}
continue
}
- mem = x.rewriteDereference(v.Block, auxBase, a, mem, auxOffset, auxSize, auxType, pos)
+ mem = x.rewriteDereference(v.Block, auxBase, a, mem, auxOffset, auxSize, auxType, a.Pos)
} else {
if a.Op == OpLoad && a.Args[0].Op == OpLocalAddr {
addr := a.Args[0] // This is a self-move. // TODO(register args) do what here for registers?
@@ -1257,13 +1295,13 @@ func expandCalls(f *Func) {
b.SetControl(v)
for _, a := range oldArgs {
if a.Uses == 0 {
- if x.debug {
+ if x.debug > 1 {
x.Printf("...marking %v unused\n", a.LongString())
}
- a.invalidateRecursively()
+ x.invalidateRecursively(a)
}
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("...multiValueExit new result %s\n", v.LongString())
}
x.indent(-3)
@@ -1317,7 +1355,7 @@ func expandCalls(f *Func) {
switch w.Op {
case OpStructSelect, OpArraySelect, OpSelectN, OpArg:
val2Preds[w] += 1
- if x.debug {
+ if x.debug > 1 {
x.Printf("v2p[%s] = %d\n", w.LongString(), val2Preds[w])
}
}
@@ -1326,7 +1364,7 @@ func expandCalls(f *Func) {
case OpSelectN:
if _, ok := val2Preds[v]; !ok {
val2Preds[v] = 0
- if x.debug {
+ if x.debug > 1 {
x.Printf("v2p[%s] = %d\n", v.LongString(), val2Preds[v])
}
}
@@ -1337,7 +1375,7 @@ func expandCalls(f *Func) {
}
if _, ok := val2Preds[v]; !ok {
val2Preds[v] = 0
- if x.debug {
+ if x.debug > 1 {
x.Printf("v2p[%s] = %d\n", v.LongString(), val2Preds[v])
}
}
@@ -1451,7 +1489,7 @@ func expandCalls(f *Func) {
if dupe == nil {
x.commonSelectors[sk] = v
} else if x.sdom.IsAncestorEq(dupe.Block, v.Block) {
- if x.debug {
+ if x.debug > 1 {
x.Printf("Duplicate, make %s copy of %s\n", v, dupe)
}
v.copyOf(dupe)
@@ -1467,12 +1505,12 @@ func expandCalls(f *Func) {
// Rewrite selectors.
for i, v := range allOrdered {
- if x.debug {
+ if x.debug > 1 {
b := v.Block
x.Printf("allOrdered[%d] = b%d, %s, uses=%d\n", i, b.ID, v.LongString(), v.Uses)
}
if v.Uses == 0 {
- v.invalidateRecursively()
+ x.invalidateRecursively(v)
continue
}
if v.Op == OpCopy {
@@ -1512,6 +1550,10 @@ func expandCalls(f *Func) {
v.Op = OpStaticCall
rts := abi.RegisterTypes(v.Aux.(*AuxCall).abiInfo.OutParams())
v.Type = types.NewResults(append(rts, types.TypeMem))
+ case OpTailLECall:
+ v.Op = OpTailCall
+ rts := abi.RegisterTypes(v.Aux.(*AuxCall).abiInfo.OutParams())
+ v.Type = types.NewResults(append(rts, types.TypeMem))
case OpClosureLECall:
v.Op = OpClosureCall
rts := abi.RegisterTypes(v.Aux.(*AuxCall).abiInfo.OutParams())
@@ -1583,7 +1625,7 @@ func expandCalls(f *Func) {
v.SetArg(i, aa)
for a.Uses == 0 {
b := a.Args[0]
- a.invalidateRecursively()
+ x.invalidateRecursively(a)
a = b
}
}
@@ -1619,7 +1661,7 @@ func expandCalls(f *Func) {
// rewriteArgToMemOrRegs converts OpArg v in-place into the register version of v,
// if that is appropriate.
func (x *expandState) rewriteArgToMemOrRegs(v *Value) *Value {
- if x.debug {
+ if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
x.Printf("rewriteArgToMemOrRegs(%s)\n", v.LongString())
@@ -1650,7 +1692,7 @@ func (x *expandState) rewriteArgToMemOrRegs(v *Value) *Value {
default:
panic(badVal("Saw unexpanded OpArg", v))
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("-->%s\n", v.LongString())
}
return v
@@ -1660,7 +1702,7 @@ func (x *expandState) rewriteArgToMemOrRegs(v *Value) *Value {
// or rewrites it into a copy of the appropriate OpArgXXX. The actual OpArgXXX is determined by combining baseArg (an OpArg)
// with offset, regOffset, and t to determine which portion of it to reference (either all or a part, in memory or in registers).
func (x *expandState) newArgToMemOrRegs(baseArg, toReplace *Value, offset int64, regOffset Abi1RO, t *types.Type, pos src.XPos) *Value {
- if x.debug {
+ if x.debug > 1 {
x.indent(3)
defer x.indent(-3)
x.Printf("newArgToMemOrRegs(base=%s; toReplace=%s; t=%s; memOff=%d; regOff=%d)\n", baseArg.String(), toReplace.LongString(), t.String(), offset, regOffset)
@@ -1696,7 +1738,7 @@ func (x *expandState) newArgToMemOrRegs(baseArg, toReplace *Value, offset int64,
if toReplace != nil {
toReplace.copyOf(w)
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("-->%s\n", w.LongString())
}
return w
@@ -1727,7 +1769,7 @@ func (x *expandState) newArgToMemOrRegs(baseArg, toReplace *Value, offset int64,
if toReplace != nil {
toReplace.copyOf(w)
}
- if x.debug {
+ if x.debug > 1 {
x.Printf("-->%s\n", w.LongString())
}
return w
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