cmd/compile: remove regabi magic names

When developing register ABI, for early testing the compiler
recognized a few magic names to trigger enabling register ABI.
After the development it is disabled (changed to a name that
cannot be spelled in the source code). Later in the development of
register ABI for ARM64 and PPC64, I don't think the magic names
were used. I think they can now be removed.

Keep the magic pragma for now in case it helps development.

Change-Id: Icbc34e2786a80fd8fffe4a464c569dc03a54cd09
Reviewed-on: https://go-review.googlesource.com/c/go/+/393877
Trust: Cherry Mui <[email protected]>
Run-TryBot: Cherry Mui <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: David Chase <[email protected]>

src/cmd/compile/internal/ssagen/ssa.go

@@ -224,11 +224,6 @@ func AbiForBodylessFuncStackMap(fn *ir.Func) *abi.ABIConfig {
  return ssaConfig.ABI0.Copy() // No idea what races will result, be safe
 }
 
-// These are disabled but remain ready for use in case they are needed for the next regabi port.
-// TODO if they are not needed for 1.18 / next register abi port, delete them.
-const magicNameDotSuffix = ".*disabled*MagicMethodNameForTestingRegisterABI"
-const magicLastTypeName = "*disabled*MagicLastTypeNameForTestingRegisterABI"
-
 // abiForFunc implements ABI policy for a function, but does not return a copy of the ABI.
 // Passing a nil function returns the default ABI based on experiment configuration.
 func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
@@ -251,36 +246,13 @@ func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
 
  a := abi0
  if fn != nil {
- name := ir.FuncName(fn)
- magicName := strings.HasSuffix(name, magicNameDotSuffix)
  if fn.Pragma&ir.RegisterParams != 0 { // TODO(register args) remove after register abi is working
- if strings.Contains(name, ".") {
- if !magicName {
- base.ErrorfAt(fn.Pos(), "Calls to //go:registerparams method %s won't work, remove the pragma from the declaration.", name)
- }
- }
- a = abi1
- } else if magicName {
- if base.FmtPos(fn.Pos()) == "<autogenerated>:1" {
- // no way to put a pragma here, and it will error out in the real source code if they did not do it there.
- a = abi1
- } else {
- base.ErrorfAt(fn.Pos(), "Methods with magic name %s (method %s) must also specify //go:registerparams", magicNameDotSuffix[1:], name)
- }
- }
- if regAbiForFuncType(fn.Type().FuncType()) {
- // fmt.Printf("Saw magic last type name for function %s\n", name)
  a = abi1
  }
  }
  return a
 }
 
-func regAbiForFuncType(ft *types.Func) bool {
- np := ft.Params.NumFields()
- return np > 0 && strings.Contains(ft.Params.FieldType(np-1).String(), magicLastTypeName)
-}
-
 // dvarint writes a varint v to the funcdata in symbol x and returns the new offset
 func dvarint(x *obj.LSym, off int, v int64) int {
  if v < 0 || v > 1e9 {
@@ -4950,24 +4922,6 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 
  callABI := s.f.ABIDefault
 
- if !buildcfg.Experiment.RegabiArgs {
- var magicFnNameSym *types.Sym
- if fn.Name() != nil {
- magicFnNameSym = fn.Name().Sym()
- ss := magicFnNameSym.Name
- if strings.HasSuffix(ss, magicNameDotSuffix) {
- callABI = s.f.ABI1
- }
- }
- if magicFnNameSym == nil && n.Op() == ir.OCALLINTER {
- magicFnNameSym = fn.(*ir.SelectorExpr).Sym()
- ss := magicFnNameSym.Name
- if strings.HasSuffix(ss, magicNameDotSuffix[1:]) {
- callABI = s.f.ABI1
- }
- }
- }
-
  if k != callNormal && k != callTail && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.X.Type().NumResults() != 0) {
  s.Fatalf("go/defer call with arguments: %v", n)
  }
@@ -5016,13 +4970,6 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
  }
  }
 
- if !buildcfg.Experiment.RegabiArgs {
- if regAbiForFuncType(n.X.Type().FuncType()) {
- // Magic last type in input args to call
- callABI = s.f.ABI1
- }
- }
-
  params := callABI.ABIAnalyze(n.X.Type(), false /* Do not set (register) nNames from caller side -- can cause races. */)
  types.CalcSize(fn.Type())
  stksize := params.ArgWidth() // includes receiver, args, and results