go.tools/ssa: combine CallCommon.{Recv,Func} as Value.

Also:
- add types.Func.FullName() (e.g. "fmt.Println", "(main.S).f")
- remove rogue print stmt.
- fix bad docstrings.

R=gri
CC=golang-dev
https://golang.org/cl/11936044

go/types/objects.go

@@ -196,10 +196,15 @@ func NewFunc(pos token.Pos, pkg *Package, name string, typ Type) *Func {
 	return &Func{object{nil, pos, pkg, name, typ}}
 }
 
-func (obj *Func) String() string {
+// FullName returns the package- or receiver-type-qualified name of
+// function or method obj.
+func (obj *Func) FullName() string {
 	var buf bytes.Buffer
+	obj.fullname(&buf)
+	return buf.String()
+}
 
-	buf.WriteString("func ")
+func (obj *Func) fullname(buf *bytes.Buffer) {
 	sig := obj.typ.(*Signature)
 	if recv := sig.Recv(); recv != nil {
 		buf.WriteByte('(')
@@ -210,17 +215,22 @@ func (obj *Func) String() string {
 			// Don't print it in full.
 			buf.WriteString("interface")
 		} else {
-			writeType(&buf, recv.Type())
+			writeType(buf, recv.Type())
 		}
 		buf.WriteByte(')')
-		buf.WriteByte(' ')
+		buf.WriteByte('.')
-	}
+	} else if obj.pkg != nil {
-	if obj.pkg != nil {
 		buf.WriteString(obj.pkg.name)
 		buf.WriteByte('.')
 	}
 	buf.WriteString(obj.name)
-	writeSignature(&buf, sig)
+}
+
+func (obj *Func) String() string {
+	var buf bytes.Buffer
+	buf.WriteString("func ")
+	obj.fullname(&buf)
+	writeSignature(&buf, obj.typ.(*Signature))
 	return buf.String()
 }
 

ssa/blockopt.go

@@ -60,7 +60,6 @@ func jumpThreading(f *Function, b *BasicBlock) bool {
 		return false // don't apply to entry block
 	}
 	if b.Instrs == nil {
-		fmt.Println("empty block ", b)
 		return false
 	}
 	if _, ok := b.Instrs[0].(*Jump); !ok {

ssa/builder.go

@@ -778,7 +778,7 @@ func (b *builder) setCallFunc(fn *Function, e *ast.CallExpr, c *CallCommon) {
 	// e.Fun is not a selector.
 	// Evaluate it in the usual way.
 	if !ok {
-		c.Func = b.expr(fn, e.Fun)
+		c.Value = b.expr(fn, e.Fun)
 		return
 	}
 
@@ -787,7 +787,7 @@ func (b *builder) setCallFunc(fn *Function, e *ast.CallExpr, c *CallCommon) {
 	// e.Fun refers to a package-level func or var.
 	// Evaluate it in the usual way.
 	if selKind == token.PACKAGE {
-		c.Func = b.expr(fn, e.Fun)
+		c.Value = b.expr(fn, e.Fun)
 		return
 	}
 
@@ -802,7 +802,7 @@ func (b *builder) setCallFunc(fn *Function, e *ast.CallExpr, c *CallCommon) {
 		// interface wrapper function, or promotion wrapper.
 		//
 		// For now, we evaluate it in the usual way.
-		c.Func = b.expr(fn, e.Fun)
+		c.Value = b.expr(fn, e.Fun)
 
 		// TODO(adonovan): opt: inline expr() here, to make
 		// the call static and to avoid generation of
@@ -841,11 +841,11 @@ func (b *builder) setCallFunc(fn *Function, e *ast.CallExpr, c *CallCommon) {
 				v = emitLoad(fn, v)
 			}
 			// Invoke-mode call.
-			c.Recv = v
+			c.Value = v
 			c.Method = obj
 		} else {
 			// "Call"-mode call.
-			c.Func = fn.Prog.concreteMethod(obj)
+			c.Value = fn.Prog.concreteMethod(obj)
 			c.Args = append(c.Args, v)
 		}
 		return
@@ -854,7 +854,7 @@ func (b *builder) setCallFunc(fn *Function, e *ast.CallExpr, c *CallCommon) {
 		// Field access: x.f() where x.f is a function value
 		// in a struct field f; not a method call.
 		// Evaluate it in the usual way.
-		c.Func = b.expr(fn, e.Fun)
+		c.Value = b.expr(fn, e.Fun)
 		return
 	}
 
@@ -1731,7 +1731,7 @@ func (b *builder) rangeIndexed(fn *Function, x Value, tv types.Type) (k, v Value
 	} else {
 		// length = len(x).
 		var c Call
-		c.Call.Func = fn.Prog.builtins[types.Universe.Lookup("len")]
+		c.Call.Value = fn.Prog.builtins[types.Universe.Lookup("len")]
 		c.Call.Args = []Value{x}
 		c.setType(tInt)
 		length = fn.emit(&c)
@@ -2336,7 +2336,7 @@ func (p *Package) Build() {
 	// Call the init() function of each package we import.
 	for _, obj := range p.info.Imports() {
 		var v Call
-		v.Call.Func = p.Prog.packages[obj].init
+		v.Call.Value = p.Prog.packages[obj].init
 		v.Call.pos = init.pos
 		v.setType(types.NewTuple())
 		init.emit(&v)

ssa/interp/interp.go

@@ -382,12 +382,13 @@ func visitInstr(fr *frame, instr ssa.Instruction) continuation {
 // interface method lookup if needed.
 //
 func prepareCall(fr *frame, call *ssa.CallCommon) (fn value, args []value) {
-	if call.Func != nil {
+	v := fr.get(call.Value)
+	if call.Method == nil {
 		// Function call.
-		fn = fr.get(call.Func)
+		fn = v
 	} else {
 		// Interface method invocation.
-		recv := fr.get(call.Recv).(iface)
+		recv := v.(iface)
 		if recv.t == nil {
 			panic("method invoked on nil interface")
 		}

ssa/print.go

@@ -111,9 +111,9 @@ func printCall(v *CallCommon, prefix string, instr Instruction) string {
 	var b bytes.Buffer
 	b.WriteString(prefix)
 	if !v.IsInvoke() {
-		b.WriteString(relName(v.Func, instr))
+		b.WriteString(relName(v.Value, instr))
 	} else {
-		fmt.Fprintf(&b, "invoke %s.%s", relName(v.Recv, instr), v.Method.Name())
+		fmt.Fprintf(&b, "invoke %s.%s", relName(v.Value, instr), v.Method.Name())
 	}
 	b.WriteString("(")
 	for i, arg := range v.Args {

ssa/promote.go

@@ -51,8 +51,8 @@ func (prog *Program) MethodSet(typ types.Type) MethodSet {
 }
 
 // populateMethodSet returns the method set for typ, ensuring that it
-// contains at least the value for obj, if that is a key.
+// contains at least the function for meth, if that is a key.
-// If id is empty, the entire method set is populated.
+// If meth is nil, the entire method set is populated.
 //
 // EXCLUSIVE_LOCKS_ACQUIRED(prog.methodsMu)
 //
@@ -106,8 +106,9 @@ func methodSet(typ types.Type) *types.MethodSet {
 	return typ.MethodSet()
 }
 
-// LookupMethod returns the method id of type typ, building wrapper
+// LookupMethod returns the Function for the specified method object,
-// methods on demand.  It returns nil if the typ has no such method.
+// building wrapper methods on demand.  It returns nil if the typ has
+// no such method.
 //
 // Thread-safe.
 //
@@ -146,7 +147,6 @@ func findMethod(prog *Program, meth *types.Method) *Function {
 		return interfaceMethodWrapper(prog, meth.Recv(), meth.Func)
 	}
 
-	// Invariant: fn.Signature.Recv().Type() == recvType(meth.Func)
 	return prog.concreteMethod(meth.Func)
 }
 
@@ -175,7 +175,7 @@ func makeWrapper(prog *Program, typ types.Type, meth *types.Method) *Function {
 	old := meth.Func.Type().(*types.Signature)
 	sig := types.NewSignature(nil, types.NewVar(token.NoPos, nil, "recv", typ), old.Params(), old.Results(), old.IsVariadic())
 
-	description := fmt.Sprintf("wrapper for (%s).%s", old.Recv(), meth.Func.Name())
+	description := fmt.Sprintf("wrapper for %s", meth.Func)
 	if prog.mode&LogSource != 0 {
 		defer logStack("make %s to (%s)", description, typ)()
 	}
@@ -218,11 +218,11 @@ func makeWrapper(prog *Program, typ types.Type, meth *types.Method) *Function {
 		if !isPointer(old.Recv().Type()) {
 			v = emitLoad(fn, v)
 		}
-		c.Call.Func = prog.concreteMethod(meth.Func)
+		c.Call.Value = prog.concreteMethod(meth.Func)
 		c.Call.Args = append(c.Call.Args, v)
 	} else {
 		c.Call.Method = meth.Func
-		c.Call.Recv = emitLoad(fn, v)
+		c.Call.Value = emitLoad(fn, v)
 	}
 	for _, arg := range fn.Params[1:] {
 		c.Call.Args = append(c.Call.Args, arg)
@@ -298,7 +298,7 @@ func interfaceMethodWrapper(prog *Program, typ types.Type, obj *types.Func) *Fun
 		var c Call
 
 		c.Call.Method = obj
-		c.Call.Recv = fn.Params[0]
+		c.Call.Value = fn.Params[0]
 		for _, arg := range fn.Params[1:] {
 			c.Call.Args = append(c.Call.Args, arg)
 		}
@@ -341,24 +341,24 @@ func boundMethodWrapper(prog *Program, obj *types.Func) *Function {
 		}
 		s := obj.Type().(*types.Signature)
 		fn = &Function{
-			name:      "bound$" + obj.String(),
+			name:      "bound$" + obj.FullName(),
-			Signature: types.NewSignature(nil, nil, s.Params(), s.Results(), s.IsVariadic()), // drop recv
+			Signature: types.NewSignature(nil, nil, s.Params(), s.Results(), s.IsVariadic()),
 			Synthetic: description,
 			Prog:      prog,
 			pos:       obj.Pos(),
 		}
 
-		cap := &Capture{name: "recv", typ: s.Recv().Type(), parent: fn}
+		cap := &Capture{name: "recv", typ: recvType(obj), parent: fn}
 		fn.FreeVars = []*Capture{cap}
 		fn.startBody()
 		createParams(fn)
 		var c Call
 
 		if _, ok := recvType(obj).Underlying().(*types.Interface); !ok { // concrete
-			c.Call.Func = prog.concreteMethod(obj)
+			c.Call.Value = prog.concreteMethod(obj)
 			c.Call.Args = []Value{cap}
 		} else {
-			c.Call.Recv = cap
+			c.Call.Value = cap
 			c.Call.Method = obj
 		}
 		for _, arg := range fn.Params {

ssa/ssa.go

@@ -1182,19 +1182,18 @@ type anInstruction struct {
 // interface method invocation, or "call" and "invoke" for short.
 //
 // 1. "call" mode: when Method is nil (!IsInvoke), a CallCommon
-// represents an ordinary function call of the value in Func.
+// represents an ordinary function call of the value in Value.
 //
-// In the common case in which Func is a *Function, this indicates a
+// In the common case in which Value is a *Function, this indicates a
 // statically dispatched call to a package-level function, an
 // anonymous function, or a method of a named type.  Also statically
-// dispatched, but less common, Func may be a *MakeClosure, indicating
+// dispatched, but less common, Value may be a *MakeClosure, indicating
 // an immediately applied function literal with free variables.  Any
-// other Value of Func indicates a dynamically dispatched function
+// other value of Value indicates a dynamically dispatched function
 // call.  The StaticCallee method returns the callee in these cases.
 //
-// Args contains the arguments to the call.  If Func is a method,
+// Args contains the arguments to the call.  If Value is a method,
-// Args[0] contains the receiver parameter.  Recv and Method are not
+// Args[0] contains the receiver parameter.
-// used in this mode.
 //
 // Example printed form:
 // 	t2 = println(t0, t1)
@@ -1203,13 +1202,12 @@ type anInstruction struct {
 //
 // 2. "invoke" mode: when Method is non-nil (IsInvoke), a CallCommon
 // represents a dynamically dispatched call to an interface method.
-// In this mode, Recv is the interface value and Method is the
+// In this mode, Value is the interface value and Method is the
 // interface's abstract method.
 //
-// Recv is implicitly supplied to the concrete method implementation
+// Value is implicitly supplied to the concrete method implementation
 // as the receiver parameter; in other words, Args[0] holds not the
-// receiver but the first true argument.  Func is not used in this
+// receiver but the first true argument.
-// mode.
 //
 // Example printed form:
 // 	t1 = invoke t0.String()
@@ -1223,11 +1221,9 @@ type anInstruction struct {
 // readability of the printed form.)
 //
 type CallCommon struct {
-	// TODO(adonovan): combine Recv/Func fields since Method now discriminates.
+	Value       Value       // receiver (invoke mode) or func value (call mode)
-	Recv        Value       // receiver (in "invoke" mode)
+	Method      *types.Func // abstract method (invoke mode)
-	Method      *types.Func // abstract method (in "invoke" mode)
+	Args        []Value     // actual parameters (in static method call, includes receiver)
-	Func        Value       // target of call (in "call" mode)
-	Args        []Value     // actual parameters, including receiver in invoke mode
 	HasEllipsis bool        // true iff last Args is a slice of '...' args (needed?)
 	pos         token.Pos   // position of CallExpr.Lparen, iff explicit in source
 }
@@ -1253,14 +1249,14 @@ func (c *CallCommon) Signature() *types.Signature {
 	if c.Method != nil {
 		return c.Method.Type().(*types.Signature)
 	}
-	sig, _ := c.Func.Type().Underlying().(*types.Signature) // nil for *Builtin
+	sig, _ := c.Value.Type().Underlying().(*types.Signature) // nil for *Builtin
 	return sig
 }
 
 // StaticCallee returns the called function if this is a trivially
 // static "call"-mode call.
 func (c *CallCommon) StaticCallee() *Function {
-	switch fn := c.Func.(type) {
+	switch fn := c.Value.(type) {
 	case *Function:
 		return fn
 	case *MakeClosure:
@@ -1272,7 +1268,7 @@ func (c *CallCommon) StaticCallee() *Function {
 // Description returns a description of the mode of this call suitable
 // for a user interface, e.g. "static method call".
 func (c *CallCommon) Description() string {
-	switch fn := c.Func.(type) {
+	switch fn := c.Value.(type) {
 	case nil:
 		return "dynamic method call" // ("invoke" mode)
 	case *MakeClosure:
@@ -1429,7 +1425,7 @@ func (v *BinOp) Operands(rands []*Value) []*Value {
 }
 
 func (c *CallCommon) Operands(rands []*Value) []*Value {
-	rands = append(rands, &c.Recv, &c.Func)
+	rands = append(rands, &c.Value)
 	for i := range c.Args {
 		rands = append(rands, &c.Args[i])
 	}