qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-11 18:51:37 -07:00
Code Releases Activity

cmd/compile: constant-fold loads from constant dictionaries and types

Browse Source 
Retrying the original CL with a small modification. The original CL
did not handle the case of reading an itab out of a dictionary
correctly.  When we read an itab out of a dictionary, we must treat
the type inside that itab as maybe being put in an interface.

Original CL: 486895
Revert CL: 490156

Change-Id: Id2dc1699d184cd8c63dac83986a70b60b4e6cbd7
Reviewed-on: https://go-review.googlesource.com/c/go/+/491495
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
This commit is contained in:
Keith Randall 2023-05-02 17:37:00 +00:00 committed by Keith Randall
parent b60db8f7d9
commit bd3f44e4ff
11 changed files with 513 additions and 56 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/cmd/compile/internal/noder/reader.go
View File

@ -3993,7 +3993,7 @@ func setBasePos(pos src.XPos) {
//
// N.B., this variable name is known to Delve:
// https://github.com/go-delve/delve/blob/cb91509630529e6055be845688fd21eb89ae8714/pkg/proc/eval.go#L28
const dictParamName = ".dict"
const dictParamName = typecheck.LocalDictName
// shapeSig returns a copy of fn's signature, except adding a
// dictionary parameter and promoting the receiver parameter (if any)

13
src/cmd/compile/internal/reflectdata/reflect.go
View File

@ -835,7 +835,14 @@ func TypeLinksymLookup(name string) *obj.LSym {
}
func TypeLinksym(t *types.Type) *obj.LSym {
return TypeSym(t).Linksym()
lsym := TypeSym(t).Linksym()
signatmu.Lock()
if lsym.Extra == nil {
ti := lsym.NewTypeInfo()
ti.Type = t
}
signatmu.Unlock()
return lsym
}
// Deprecated: Use TypePtrAt instead.
@ -1869,7 +1876,9 @@ func MarkTypeUsedInInterface(t *types.Type, from *obj.LSym) {
// Shape types shouldn't be put in interfaces, so we shouldn't ever get here.
base.Fatalf("shape types have no methods %+v", t)
}
tsym := TypeLinksym(t)
MarkTypeSymUsedInInterface(TypeLinksym(t), from)
}
func MarkTypeSymUsedInInterface(tsym *obj.LSym, from *obj.LSym) {
// Emit a marker relocation. The linker will know the type is converted
// to an interface if "from" is reachable.
r := obj.Addrel(from)

27
src/cmd/compile/internal/ssa/_gen/generic.rules
View File

@ -2065,6 +2065,10 @@
&& warnRule(fe.Debug_checknil(), v, "removed nil check")
=> (Invalid)
// Addresses of globals are always non-nil.
(NilCheck (Addr {_} (SB)) _) => (Invalid)
(NilCheck (Convert (Addr {_} (SB)) _) _) => (Invalid)
// for late-expanded calls, recognize memequal applied to a single constant byte
// Support is limited by 1, 2, 4, 8 byte sizes
(StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [1]) mem)
@ -2152,6 +2156,8 @@
(NeqPtr (OffPtr [o1] p1) (OffPtr [o2] p2)) && isSamePtr(p1, p2) => (ConstBool [o1 != o2])
(EqPtr (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c == d])
(NeqPtr (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c != d])
(EqPtr (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x==y])
(NeqPtr (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x!=y])
(EqPtr (LocalAddr _ _) (Addr _)) => (ConstBool [false])
(EqPtr (OffPtr (LocalAddr _ _)) (Addr _)) => (ConstBool [false])
@ -2173,7 +2179,8 @@
// Evaluate constant user nil checks.
(IsNonNil (ConstNil)) => (ConstBool [false])
(IsNonNil (Const(32|64) [c])) => (ConstBool [c != 0])
(IsNonNil (Addr _)) => (ConstBool [true])
(IsNonNil (Addr _) ) => (ConstBool [true])
(IsNonNil (Convert (Addr _) _)) => (ConstBool [true])
(IsNonNil (LocalAddr _ _)) => (ConstBool [true])
// Inline small or disjoint runtime.memmove calls with constant length.
@ -2216,11 +2223,7 @@
=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
// De-virtualize late-expanded interface calls into late-expanded static calls.
// Note that (ITab (IMake)) doesn't get rewritten until after the first opt pass,
// so this rule should trigger reliably.
// devirtLECall removes the first argument, adds the devirtualized symbol to the AuxCall, and changes the opcode
(InterLECall [argsize] {auxCall} (Load (OffPtr [off] (ITab (IMake (Addr {itab} (SB)) _))) _) ___) && devirtLESym(v, auxCall, itab, off) !=
nil => devirtLECall(v, devirtLESym(v, auxCall, itab, off))
(InterLECall [argsize] {auxCall} (Addr {fn} (SB)) ___) => devirtLECall(v, fn.(*obj.LSym))
// Move and Zero optimizations.
// Move source and destination may overlap.
@ -2734,3 +2737,15 @@
(RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 4 && d.Type.Size() == 4 => (RotateLeft(64|32|16|8) x (Add32 <c.Type> c d))
(RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 2 && d.Type.Size() == 2 => (RotateLeft(64|32|16|8) x (Add16 <c.Type> c d))
(RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 1 && d.Type.Size() == 1 => (RotateLeft(64|32|16|8) x (Add8 <c.Type> c d))
// Loading constant values from dictionaries and itabs.
(Load <t> (OffPtr [off] (Addr {s} sb) ) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <t> (OffPtr [off] (Convert (Addr {s} sb) _) ) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <t> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
// Loading constant values from runtime._type.hash.
(Load <t> (OffPtr [off] (Addr {sym} _) ) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])
(Load <t> (OffPtr [off] (Convert (Addr {sym} _) _) ) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])
(Load <t> (OffPtr [off] (ITab (IMake (Addr {sym} _) _))) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])
(Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {sym} _) _) _))) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])

95
src/cmd/compile/internal/ssa/rewrite.go
View File

@ -7,6 +7,7 @@ package ssa
import (
"cmd/compile/internal/base"
"cmd/compile/internal/logopt"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/types"
"cmd/internal/obj"
"cmd/internal/obj/s390x"
@ -20,6 +21,7 @@ import (
"math/bits"
"os"
"path/filepath"
"strings"
)
type deadValueChoice bool
@ -800,25 +802,6 @@ func loadLSymOffset(lsym *obj.LSym, offset int64) *obj.LSym {
return nil
}
// de-virtualize an InterLECall
// 'sym' is the symbol for the itab.
func devirtLESym(v *Value, aux Aux, sym Sym, offset int64) *obj.LSym {
n, ok := sym.(*obj.LSym)
if !ok {
return nil
}
lsym := loadLSymOffset(n, offset)
if f := v.Block.Func; f.pass.debug > 0 {
if lsym != nil {
f.Warnl(v.Pos, "de-virtualizing call")
} else {
f.Warnl(v.Pos, "couldn't de-virtualize call")
}
}
return lsym
}
func devirtLECall(v *Value, sym *obj.LSym) *Value {
v.Op = OpStaticLECall
auxcall := v.Aux.(*AuxCall)
@ -828,6 +811,9 @@ func devirtLECall(v *Value, sym *obj.LSym) *Value {
copy(v.Args[0:], v.Args[1:])
v.Args[len(v.Args)-1] = nil // aid GC
v.Args = v.Args[:len(v.Args)-1]
if f := v.Block.Func; f.pass.debug > 0 {
f.Warnl(v.Pos, "de-virtualizing call")
}
return v
}
@ -1750,6 +1736,77 @@ func symIsROZero(sym Sym) bool {
return true
}
// isFixed32 returns true if the int32 at offset off in symbol sym
// is known and constant.
func isFixed32(c *Config, sym Sym, off int64) bool {
return isFixed(c, sym, off, 4)
}
// isFixed returns true if the range [off,off+size] of the symbol sym
// is known and constant.
func isFixed(c *Config, sym Sym, off, size int64) bool {
lsym := sym.(*obj.LSym)
if lsym.Extra == nil {
return false
}
if _, ok := (*lsym.Extra).(*obj.TypeInfo); ok {
if off == 2*c.PtrSize && size == 4 {
return true // type hash field
}
}
return false
}
func fixed32(c *Config, sym Sym, off int64) int32 {
lsym := sym.(*obj.LSym)
if ti, ok := (*lsym.Extra).(*obj.TypeInfo); ok {
if off == 2*c.PtrSize {
return int32(types.TypeHash(ti.Type.(*types.Type)))
}
}
base.Fatalf("fixed32 data not known for %s:%d", sym, off)
return 0
}
// isFixedSym returns true if the contents of sym at the given offset
// is known and is the constant address of another symbol.
func isFixedSym(sym Sym, off int64) bool {
lsym := sym.(*obj.LSym)
switch {
case lsym.Type == objabi.SRODATA:
// itabs, dictionaries
default:
return false
}
for _, r := range lsym.R {
if (r.Type == objabi.R_ADDR || r.Type == objabi.R_WEAKADDR) && int64(r.Off) == off && r.Add == 0 {
return true
}
}
return false
}
func fixedSym(f *Func, sym Sym, off int64) Sym {
lsym := sym.(*obj.LSym)
for _, r := range lsym.R {
if (r.Type == objabi.R_ADDR || r.Type == objabi.R_WEAKADDR) && int64(r.Off) == off {
if strings.HasPrefix(r.Sym.Name, "type:") {
// In case we're loading a type out of a dictionary, we need to record
// that the containing function might put that type in an interface.
// That information is currently recorded in relocations in the dictionary,
// but if we perform this load at compile time then the dictionary
// might be dead.
reflectdata.MarkTypeSymUsedInInterface(r.Sym, f.fe.Func().Linksym())
} else if strings.HasPrefix(r.Sym.Name, "go:itab") {
// Same, but if we're using an itab we need to record that the
// itab._type might be put in an interface.
reflectdata.MarkTypeSymUsedInInterface(r.Sym, f.fe.Func().Linksym())
}
return r.Sym
}
}
base.Fatalf("fixedSym data not known for %s:%d", sym, off)
return nil
}
// read8 reads one byte from the read-only global sym at offset off.
func read8(sym interface{}, off int64) uint8 {
lsym := sym.(*obj.LSym)

347
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -3,6 +3,7 @@
package ssa
import "math"
import "cmd/internal/obj"
import "cmd/compile/internal/types"
import "cmd/compile/internal/ir"
@ -10201,6 +10202,28 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
}
break
}
// match: (EqPtr (Convert (Addr {x} _) _) (Addr {y} _))
// result: (ConstBool [x==y])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpConvert {
continue
}
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpAddr {
continue
}
x := auxToSym(v_0_0.Aux)
if v_1.Op != OpAddr {
continue
}
y := auxToSym(v_1.Aux)
v.reset(OpConstBool)
v.AuxInt = boolToAuxInt(x == y)
return true
}
break
}
// match: (EqPtr (LocalAddr _ _) (Addr _))
// result: (ConstBool [false])
for {
@ -10405,41 +10428,22 @@ func rewriteValuegeneric_OpIMake(v *Value) bool {
return false
}
func rewriteValuegeneric_OpInterLECall(v *Value) bool {
// match: (InterLECall [argsize] {auxCall} (Load (OffPtr [off] (ITab (IMake (Addr {itab} (SB)) _))) _) ___)
// cond: devirtLESym(v, auxCall, itab, off) != nil
// result: devirtLECall(v, devirtLESym(v, auxCall, itab, off))
// match: (InterLECall [argsize] {auxCall} (Addr {fn} (SB)) ___)
// result: devirtLECall(v, fn.(*obj.LSym))
for {
if len(v.Args) < 1 {
break
}
auxCall := auxToCall(v.Aux)
v_0 := v.Args[0]
if v_0.Op != OpLoad {
if v_0.Op != OpAddr {
break
}
fn := auxToSym(v_0.Aux)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpOffPtr {
if v_0_0.Op != OpSB {
break
}
off := auxIntToInt64(v_0_0.AuxInt)
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpITab {
break
}
v_0_0_0_0 := v_0_0_0.Args[0]
if v_0_0_0_0.Op != OpIMake {
break
}
v_0_0_0_0_0 := v_0_0_0_0.Args[0]
if v_0_0_0_0_0.Op != OpAddr {
break
}
itab := auxToSym(v_0_0_0_0_0.Aux)
v_0_0_0_0_0_0 := v_0_0_0_0_0.Args[0]
if v_0_0_0_0_0_0.Op != OpSB || !(devirtLESym(v, auxCall, itab, off) != nil) {
break
}
v.copyOf(devirtLECall(v, devirtLESym(v, auxCall, itab, off)))
v.copyOf(devirtLECall(v, fn.(*obj.LSym)))
return true
}
return false
@ -11170,7 +11174,7 @@ func rewriteValuegeneric_OpIsNonNil(v *Value) bool {
v.AuxInt = boolToAuxInt(c != 0)
return true
}
// match: (IsNonNil (Addr _))
// match: (IsNonNil (Addr _) )
// result: (ConstBool [true])
for {
if v_0.Op != OpAddr {
@ -11180,6 +11184,20 @@ func rewriteValuegeneric_OpIsNonNil(v *Value) bool {
v.AuxInt = boolToAuxInt(true)
return true
}
// match: (IsNonNil (Convert (Addr _) _))
// result: (ConstBool [true])
for {
if v_0.Op != OpConvert {
break
}
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpAddr {
break
}
v.reset(OpConstBool)
v.AuxInt = boolToAuxInt(true)
return true
}
// match: (IsNonNil (LocalAddr _ _))
// result: (ConstBool [true])
for {
@ -12566,6 +12584,7 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
v_1 := v.Args[1]
v_0 := v.Args[0]
b := v.Block
config := b.Func.Config
fe := b.Func.fe
// match: (Load <t1> p1 (Store {t2} p2 x _))
// cond: isSamePtr(p1, p2) && t1.Compare(x.Type) == types.CMPeq && t1.Size() == t2.Size()
@ -13257,6 +13276,230 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (Load <t> (OffPtr [off] (Addr {s} sb) ) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0.Aux)
sb := v_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <t> (OffPtr [off] (Convert (Addr {s} sb) _) ) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpConvert {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0_0.Aux)
sb := v_0_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <t> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpITab {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpIMake {
break
}
v_0_0_0_0 := v_0_0_0.Args[0]
if v_0_0_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0_0_0.Aux)
sb := v_0_0_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpITab {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpIMake {
break
}
v_0_0_0_0 := v_0_0_0.Args[0]
if v_0_0_0_0.Op != OpConvert {
break
}
v_0_0_0_0_0 := v_0_0_0_0.Args[0]
if v_0_0_0_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0_0_0_0.Aux)
sb := v_0_0_0_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <t> (OffPtr [off] (Addr {sym} _) ) _)
// cond: t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)
// result: (Const32 [fixed32(config, sym, off)])
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpAddr {
break
}
sym := auxToSym(v_0_0.Aux)
if !(t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)) {
break
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(fixed32(config, sym, off))
return true
}
// match: (Load <t> (OffPtr [off] (Convert (Addr {sym} _) _) ) _)
// cond: t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)
// result: (Const32 [fixed32(config, sym, off)])
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpConvert {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpAddr {
break
}
sym := auxToSym(v_0_0_0.Aux)
if !(t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)) {
break
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(fixed32(config, sym, off))
return true
}
// match: (Load <t> (OffPtr [off] (ITab (IMake (Addr {sym} _) _))) _)
// cond: t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)
// result: (Const32 [fixed32(config, sym, off)])
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpITab {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpIMake {
break
}
v_0_0_0_0 := v_0_0_0.Args[0]
if v_0_0_0_0.Op != OpAddr {
break
}
sym := auxToSym(v_0_0_0_0.Aux)
if !(t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)) {
break
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(fixed32(config, sym, off))
return true
}
// match: (Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {sym} _) _) _))) _)
// cond: t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)
// result: (Const32 [fixed32(config, sym, off)])
for {
t := v.Type
if v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpITab {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpIMake {
break
}
v_0_0_0_0 := v_0_0_0.Args[0]
if v_0_0_0_0.Op != OpConvert {
break
}
v_0_0_0_0_0 := v_0_0_0_0.Args[0]
if v_0_0_0_0_0.Op != OpAddr {
break
}
sym := auxToSym(v_0_0_0_0_0.Aux)
if !(t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off)) {
break
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(fixed32(config, sym, off))
return true
}
return false
}
func rewriteValuegeneric_OpLsh16x16(v *Value) bool {
@ -18546,6 +18789,28 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
}
break
}
// match: (NeqPtr (Convert (Addr {x} _) _) (Addr {y} _))
// result: (ConstBool [x!=y])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpConvert {
continue
}
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpAddr {
continue
}
x := auxToSym(v_0_0.Aux)
if v_1.Op != OpAddr {
continue
}
y := auxToSym(v_1.Aux)
v.reset(OpConstBool)
v.AuxInt = boolToAuxInt(x != y)
return true
}
break
}
// match: (NeqPtr (LocalAddr _ _) (Addr _))
// result: (ConstBool [true])
for {
@ -18747,6 +19012,36 @@ func rewriteValuegeneric_OpNilCheck(v *Value) bool {
v.reset(OpInvalid)
return true
}
// match: (NilCheck (Addr {_} (SB)) _)
// result: (Invalid)
for {
if v_0.Op != OpAddr {
break
}
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpSB {
break
}
v.reset(OpInvalid)
return true
}
// match: (NilCheck (Convert (Addr {_} (SB)) _) _)
// result: (Invalid)
for {
if v_0.Op != OpConvert {
break
}
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpAddr {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpSB {
break
}
v.reset(OpInvalid)
return true
}
return false
}
func rewriteValuegeneric_OpNot(v *Value) bool {

18
src/cmd/internal/obj/link.go
View File

@ -465,7 +465,7 @@ type LSym struct {
P []byte
R []Reloc
Extra *interface{} // *FuncInfo, *VarInfo, or *FileInfo, if present
Extra *interface{} // *FuncInfo, *VarInfo, *FileInfo, or *TypeInfo, if present
Pkg string
PkgIdx int32
@ -588,6 +588,22 @@ func (s *LSym) File() *FileInfo {
return f
}
// A TypeInfo contains information for a symbol
// that contains a runtime._type.
type TypeInfo struct {
Type interface{} // a *cmd/compile/internal/types.Type
}
func (s *LSym) NewTypeInfo() *TypeInfo {
if s.Extra != nil {
panic(fmt.Sprintf("invalid use of LSym - NewTypeInfo with Extra of type %T", *s.Extra))
}
t := new(TypeInfo)
s.Extra = new(interface{})
*s.Extra = t
return t
}
// WasmImport represents a WebAssembly (WASM) imported function with
// parameters and results translated into WASM types based on the Go function
// declaration.

3
src/cmd/internal/objabi/reloctype.go
View File

@ -83,7 +83,8 @@ const (
// direct references. (This is used for types reachable by reflection.)
R_USETYPE
// R_USEIFACE marks a type is converted to an interface in the function this
// relocation is applied to. The target is a type descriptor.
// relocation is applied to. The target is a type descriptor or an itab
// (in the latter case it refers to the conrete type contained in the itab).
// This is a marker relocation (0-sized), for the linker's reachabililty
// analysis.
R_USEIFACE

8
src/cmd/link/internal/ld/deadcode.go
View File

@ -180,6 +180,14 @@ func (d *deadcodePass) flood() {
// converted to an interface, i.e. should have UsedInIface set. See the
// comment below for why we need to unset the Reachable bit and re-mark it.
rs := r.Sym()
if d.ldr.IsItab(rs) {
// This relocation can also point at an itab, in which case it
// means "the _type field of that itab".
rs = decodeItabType(d.ldr, d.ctxt.Arch, rs)
}
if !d.ldr.IsGoType(rs) && !d.ctxt.linkShared {
panic(fmt.Sprintf("R_USEIFACE in %s references %s which is not a type or itab", d.ldr.SymName(symIdx), d.ldr.SymName(rs)))
}
if !d.ldr.AttrUsedInIface(rs) {
d.ldr.SetAttrUsedInIface(rs, true)
if d.ldr.AttrReachable(rs) {

6
src/cmd/link/internal/ld/decodesym.go
View File

@ -300,3 +300,9 @@ func findShlibSection(ctxt *Link, path string, addr uint64) *elf.Section {
func decodetypeGcprogShlib(ctxt *Link, data []byte) uint64 {
return decodeInuxi(ctxt.Arch, data[2*int32(ctxt.Arch.PtrSize)+8+1*int32(ctxt.Arch.PtrSize):], ctxt.Arch.PtrSize)
}
// decodeItabType returns the itab._type field from an itab.
func decodeItabType(ldr *loader.Loader, arch *sys.Arch, symIdx loader.Sym) loader.Sym {
relocs := ldr.Relocs(symIdx)
return decodeRelocSym(ldr, symIdx, &relocs, int32(arch.PtrSize))
}

22
test/typeparam/devirtualize1.go Normal file
View File

@ -0,0 +1,22 @@
// run
// Copyright 2023 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 main
type S struct {
x int
}
func (t *S) M1() {
}
func F[T any](x T) any {
return x
}
func main() {
F(&S{}).(interface{ M1() }).M1()
}

28
test/typeparam/devirtualize2.go Normal file
View File

@ -0,0 +1,28 @@
// run
// Copyright 2023 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 main
type S struct {
x int
}
func (t *S) M1() {
}
func (t *S) M2() {
}
type I interface {
M1()
}
func F[T I](x T) I {
return x
}
func main() {
F(&S{}).(interface{ M2() }).M2()
}