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cmd/compile, reflect: treat abi.NoEscape as cheap call

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The abi.NoEscape function is introduced to replace all usages of
noescape wrapper in the standard library. However, the last usage in
reflect package is still present, because the inlining test failed if
abi.NoEscape were used. The reason is that reflect.noescape is treated
as a cheap call, while abi.NoEscape is not.

By treating abi.NoEscape a cheap call, the last usage of noescape in
reflect package can now be removed.

Change-Id: I798079780129221a5a26cbcb18c95ee30855b784
Reviewed-on: https://go-review.googlesource.com/c/go/+/601275
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
Cuong Manh Le 2024-07-26 18:09:57 +07:00 committed by Gopher Robot
parent deed521ea3
commit b6efbd4efc
2 changed files with 3 additions and 13 deletions
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4
src/cmd/compile/internal/inline/inl.go
View File

@ -460,10 +460,10 @@ opSwitch:
case "panicrangestate":
cheap = true
}
// Special case for reflect.noescape. It does just type
// Special case for internal/abi.NoEscape. It does just type
// conversions to appease the escape analysis, and doesn't
// generate code.
if types.ReflectSymName(name.Sym()) == "noescape" {
if s := name.Sym(); s.Name == "NoEscape" && s.Pkg.Path == "internal/abi" {
cheap = true
}
}

12
src/reflect/value.go
View File

@ -2677,7 +2677,7 @@ func (v Value) TrySend(x Value) bool {
// Type returns v's type.
func (v Value) Type() Type {
if v.flag != 0 && v.flag&flagMethod == 0 {
return (*rtype)(noescape(unsafe.Pointer(v.typ_))) // inline of toRType(v.typ()), for own inlining in inline test
return (*rtype)(abi.NoEscape(unsafe.Pointer(v.typ_))) // inline of toRType(v.typ()), for own inlining in inline test
}
return v.typeSlow()
}
@ -4018,13 +4018,3 @@ func contentEscapes(x unsafe.Pointer) {
escapes(*(*any)(x)) // the dereference may not always be safe, but never executed
}
}
// This is just a wrapper around abi.NoEscape. The inlining heuristics are
// finnicky and for whatever reason treat the local call to noescape as much
// lower cost with respect to the inliner budget. (That is, replacing calls to
// noescape with abi.NoEscape will cause inlining tests to fail.)
//
//go:nosplit
func noescape(p unsafe.Pointer) unsafe.Pointer {
return abi.NoEscape(p)
}