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cmd/compile: use new runtime type mechanism for type switches and asserts

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Change-Id: Ife7d6d6d773ac0d8ac38dbd2da7dccc519998b63
Reviewed-on: https://go-review.googlesource.com/c/go/+/534816
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
This commit is contained in:
Keith Randall 2023-10-12 10:57:04 -07:00
parent 2d9e8ded94
commit 9ab5121691
3 changed files with 44 additions and 18 deletions
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16
src/cmd/compile/internal/walk/expr.go
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@ -14,6 +14,7 @@ import (
"cmd/compile/internal/ir"
"cmd/compile/internal/objw"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/rttype"
"cmd/compile/internal/staticdata"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
@ -738,15 +739,12 @@ func makeTypeAssertDescriptor(target *types.Type, canFail bool) *obj.LSym {
// Allocate an internal/abi.TypeAssert descriptor for that call.
lsym := types.LocalPkg.Lookup(fmt.Sprintf(".typeAssert.%d", typeAssertGen)).LinksymABI(obj.ABI0)
typeAssertGen++
off := 0
off = objw.SymPtr(lsym, off, typecheck.LookupRuntimeVar("emptyTypeAssertCache"), 0)
off = objw.SymPtr(lsym, off, reflectdata.TypeSym(target).Linksym(), 0)
off = objw.Bool(lsym, off, canFail)
off += types.PtrSize - 1
objw.Global(lsym, int32(off), obj.LOCAL)
// Set the type to be just a single pointer, as the cache pointer is the
// only one that GC needs to see.
lsym.Gotype = reflectdata.TypeLinksym(types.Types[types.TUINT8].PtrTo())
c := rttype.NewCursor(lsym, 0, rttype.TypeAssert)
c.Field("Cache").WritePtr(typecheck.LookupRuntimeVar("emptyTypeAssertCache"))
c.Field("Inter").WritePtr(reflectdata.TypeSym(target).Linksym())
c.Field("CanFail").WriteBool(canFail)
objw.Global(lsym, int32(rttype.TypeAssert.Size()), obj.LOCAL)
lsym.Gotype = reflectdata.TypeLinksym(rttype.TypeAssert)
return lsym
}