cmd/compile: expose ir.Func to ssa

ssagen.ssafn already holds the ir.Func, and ssa.Frontend.SetWBPos and
ssa.Frontend.Lsym are simple wrappers around parts of the ir.Func.

Expose the ir.Func through ssa.Frontend, allowing us to remove these
wrapper methods and allowing future access to additional features of the
ir.Func if needed.

While we're here, drop ssa.Frontend.Line, which is unused.

For #58298.

Change-Id: I30c4cbd2743e9ad991d8c6b388484a7d1e95f3ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/484215
Auto-Submit: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>

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

@@ -136,10 +136,11 @@ type Logger interface {
 }
 
 type Frontend interface {
-	CanSSA(t *types.Type) bool
-
 	Logger
 
+	// CanSSA reports whether variabbles of type t are SSA-able.
+	CanSSA(t *types.Type) bool
+
 	// StringData returns a symbol pointing to the given string's contents.
 	StringData(string) *obj.LSym
 
@@ -151,9 +152,6 @@ type Frontend interface {
 	// for the parts of that compound type.
 	SplitSlot(parent *LocalSlot, suffix string, offset int64, t *types.Type) LocalSlot
 
-	// Line returns a string describing the given position.
-	Line(src.XPos) string
-
 	// AllocFrame assigns frame offsets to all live auto variables.
 	AllocFrame(f *Func)
 
@@ -164,15 +162,11 @@ type Frontend interface {
 	// UseWriteBarrier reports whether write barrier is enabled
 	UseWriteBarrier() bool
 
-	// SetWBPos indicates that a write barrier has been inserted
-	// in this function at position pos.
-	SetWBPos(pos src.XPos)
-
 	// MyImportPath provides the import name (roughly, the package) for the function being compiled.
 	MyImportPath() string
 
-	// LSym returns the linker symbol of the function being compiled.
-	LSym() string
+	// Func returns the ir.Func of the function being compiled.
+	Func() *ir.Func
 }
 
 // NewConfig returns a new configuration object for the given architecture.

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

@@ -55,7 +55,18 @@ type Conf struct {
 
 func (c *Conf) Frontend() Frontend {
 	if c.fe == nil {
-		c.fe = TestFrontend{t: c.tb, ctxt: c.config.ctxt}
+		f := ir.NewFunc(src.NoXPos)
+		f.Nname = ir.NewNameAt(f.Pos(), &types.Sym{
+			Pkg:  types.NewPkg("my/import/path", "path"),
+			Name: "function",
+		})
+		f.LSym = &obj.LSym{Name: "my/import/path.function"}
+
+		c.fe = TestFrontend{
+			t:    c.tb,
+			ctxt: c.config.ctxt,
+			f:    f,
+		}
 	}
 	return c.fe
 }
@@ -65,6 +76,7 @@ func (c *Conf) Frontend() Frontend {
 type TestFrontend struct {
 	t    testing.TB
 	ctxt *obj.Link
+	f    *ir.Func
 }
 
 func (TestFrontend) StringData(s string) *obj.LSym {
@@ -79,9 +91,6 @@ func (TestFrontend) Auto(pos src.XPos, t *types.Type) *ir.Name {
 func (d TestFrontend) SplitSlot(parent *LocalSlot, suffix string, offset int64, t *types.Type) LocalSlot {
 	return LocalSlot{N: parent.N, Type: t, Off: offset}
 }
-func (TestFrontend) Line(_ src.XPos) string {
-	return "unknown.go:0"
-}
 func (TestFrontend) AllocFrame(f *Func) {
 }
 func (d TestFrontend) Syslook(s string) *obj.LSym {
@@ -90,8 +99,6 @@ func (d TestFrontend) Syslook(s string) *obj.LSym {
 func (TestFrontend) UseWriteBarrier() bool {
 	return true // only writebarrier_test cares
 }
-func (TestFrontend) SetWBPos(pos src.XPos) {
-}
 
 func (d TestFrontend) Logf(msg string, args ...interface{}) { d.t.Logf(msg, args...) }
 func (d TestFrontend) Log() bool                            { return true }
@@ -101,10 +108,10 @@ func (d TestFrontend) Warnl(_ src.XPos, msg string, args ...interface{})  { d.t.
 func (d TestFrontend) Debug_checknil() bool                               { return false }
 
 func (d TestFrontend) MyImportPath() string {
-	return "my/import/path"
+	return d.f.Sym().Pkg.Path
 }
-func (d TestFrontend) LSym() string {
-	return "my/import/path.function"
+func (d TestFrontend) Func() *ir.Func {
+	return d.f
 }
 
 var testTypes Types

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

@@ -1992,7 +1992,7 @@ func logicFlags32(x int32) flagConstant {
 }
 
 func makeJumpTableSym(b *Block) *obj.LSym {
-	s := base.Ctxt.Lookup(fmt.Sprintf("%s.jump%d", b.Func.fe.LSym(), b.ID))
+	s := base.Ctxt.Lookup(fmt.Sprintf("%s.jump%d", b.Func.fe.Func().LSym.Name, b.ID))
 	s.Set(obj.AttrDuplicateOK, true)
 	s.Set(obj.AttrLocal, true)
 	return s

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

@@ -406,7 +406,7 @@ func writebarrier(f *Func) {
 				// Save old value to write buffer.
 				addEntry(oldVal)
 			}
-			f.fe.SetWBPos(pos)
+			f.fe.Func().SetWBPos(pos)
 			nWBops--
 		}
 
@@ -419,7 +419,7 @@ func writebarrier(f *Func) {
 				// zeroWB(&typ, dst)
 				taddr := b.NewValue1A(pos, OpAddr, b.Func.Config.Types.Uintptr, typ, sb)
 				memThen = wbcall(pos, bThen, wbZero, sp, memThen, taddr, dst)
-				f.fe.SetWBPos(pos)
+				f.fe.Func().SetWBPos(pos)
 				nWBops--
 			case OpMoveWB:
 				dst := w.Args[0]
@@ -436,7 +436,7 @@ func writebarrier(f *Func) {
 				// moveWB(&typ, dst, src)
 				taddr := b.NewValue1A(pos, OpAddr, b.Func.Config.Types.Uintptr, typ, sb)
 				memThen = wbcall(pos, bThen, wbMove, sp, memThen, taddr, dst, src)
-				f.fe.SetWBPos(pos)
+				f.fe.Func().SetWBPos(pos)
 				nWBops--
 			}
 		}

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

@@ -7877,10 +7877,6 @@ func (e *ssafn) CanSSA(t *types.Type) bool {
 	return TypeOK(t)
 }
 
-func (e *ssafn) Line(pos src.XPos) string {
-	return base.FmtPos(pos)
-}
-
 // Logf logs a message from the compiler.
 func (e *ssafn) Logf(msg string, args ...interface{}) {
 	if e.log {
@@ -7932,16 +7928,12 @@ func (e *ssafn) Syslook(name string) *obj.LSym {
 	return nil
 }
 
-func (e *ssafn) SetWBPos(pos src.XPos) {
-	e.curfn.SetWBPos(pos)
-}
-
 func (e *ssafn) MyImportPath() string {
 	return base.Ctxt.Pkgpath
 }
 
-func (e *ssafn) LSym() string {
-	return e.curfn.LSym.Name
+func (e *ssafn) Func() *ir.Func {
+	return e.curfn
 }
 
 func clobberBase(n ir.Node) ir.Node {