go.tools/ssa: Member.Object() returns typechecker object for package members.

Also:
- {Must,}SanityCheck un-exported.  Added sanityCheckPackage.

R=gri
CC=golang-dev
https://golang.org/cl/11174043

ssa/blockopt.go

@@ -147,7 +147,7 @@ func optimizeBlocks(f *Function) {
 
 		if debugBlockOpt {
 			f.DumpTo(os.Stderr)
-			MustSanityCheck(f, nil)
+			mustSanityCheck(f, nil)
 		}
 
 		for _, b := range f.Blocks {

ssa/create.go

@@ -85,23 +85,23 @@ func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
 	name := obj.Name()
 	switch obj := obj.(type) {
 	case *types.TypeName:
-		pkg.Members[name] = &Type{Object: obj}
+		pkg.Members[name] = &Type{object: obj}
 
 	case *types.Const:
 		pkg.Members[name] = &Constant{
-			name:  name,
-			Value: NewLiteral(obj.Val(), obj.Type(), obj.Pos()),
-			pos:   obj.Pos(),
+			object: obj,
+			Value:  NewLiteral(obj.Val(), obj.Type(), obj.Pos()),
 		}
 
 	case *types.Var:
 		spec, _ := syntax.(*ast.ValueSpec)
 		g := &Global{
-			Pkg:  pkg,
-			name: name,
-			typ:  pointer(obj.Type()), // address
-			pos:  obj.Pos(),
-			spec: spec,
+			Pkg:    pkg,
+			name:   name,
+			object: obj,
+			typ:    pointer(obj.Type()), // address
+			pos:    obj.Pos(),
+			spec:   spec,
 		}
 		pkg.values[obj] = g
 		pkg.Members[name] = g
@@ -121,6 +121,7 @@ func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
 		sig := obj.Type().(*types.Signature)
 		fn := &Function{
 			name:      name,
+			object:    obj,
 			Signature: sig,
 			Synthetic: synthetic,
 			pos:       obj.Pos(), // (iff syntax)
@@ -264,4 +265,8 @@ func createPackage(prog *Program, importPath string, info *importer.PackageInfo)
 
 	prog.PackagesByPath[importPath] = p
 	prog.packages[p.Object] = p
+
+	if prog.mode&SanityCheckFunctions != 0 {
+		sanityCheckPackage(p)
+	}
 }

ssa/func.go

@@ -350,7 +350,7 @@ func (f *Function) finishBody() {
 	}
 
 	if f.Prog.mode&SanityCheckFunctions != 0 {
-		MustSanityCheck(f, nil)
+		mustSanityCheck(f, nil)
 	}
 }
 

ssa/promote.go

@@ -285,6 +285,7 @@ func promotionWrapper(prog *Program, typ types.Type, cand *candidate) *Function
 	if prog.mode&LogSource != 0 {
 		defer logStack("promotionWrapper (%s)%s, type %s", typ, cand, sig)()
 	}
+	// TODO(adonovan): is there a *types.Func for this function?
 	fn := &Function{
 		name:      cand.method.Name(),
 		Signature: sig,
@@ -395,6 +396,7 @@ func interfaceMethodWrapper(prog *Program, typ types.Type, id Id) *Function {
 		}
 		fn = &Function{
 			name:      meth.Name(),
+			object:    meth,
 			Signature: meth.Type().(*types.Signature),
 			Synthetic: fmt.Sprintf("interface method wrapper for %s.%s", typ, id),
 			pos:       meth.Pos(),
@@ -495,6 +497,7 @@ func indirectionWrapper(meth *Function) *Function {
 		s := meth.Signature
 		recv := types.NewVar(token.NoPos, meth.Pkg.Object, "recv",
 			types.NewPointer(s.Recv().Type()))
+		// TODO(adonovan): is there a *types.Func for this method?
 		fn = &Function{
 			name:      meth.Name(),
 			Signature: types.NewSignature(recv, s.Params(), s.Results(), s.IsVariadic()),

ssa/sanity.go

@@ -17,26 +17,26 @@ type sanity struct {
 	insane   bool
 }
 
-// SanityCheck performs integrity checking of the SSA representation
+// sanityCheck performs integrity checking of the SSA representation
 // of the function fn and returns true if it was valid.  Diagnostics
 // are written to reporter if non-nil, os.Stderr otherwise.  Some
 // diagnostics are only warnings and do not imply a negative result.
 //
-// Sanity checking is intended to facilitate the debugging of code
+// Sanity-checking is intended to facilitate the debugging of code
 // transformation passes.
 //
-func SanityCheck(fn *Function, reporter io.Writer) bool {
+func sanityCheck(fn *Function, reporter io.Writer) bool {
 	if reporter == nil {
 		reporter = os.Stderr
 	}
 	return (&sanity{reporter: reporter}).checkFunction(fn)
 }
 
-// MustSanityCheck is like SanityCheck but panics instead of returning
+// mustSanityCheck is like sanityCheck but panics instead of returning
 // a negative result.
 //
-func MustSanityCheck(fn *Function, reporter io.Writer) {
-	if !SanityCheck(fn, reporter) {
+func mustSanityCheck(fn *Function, reporter io.Writer) {
+	if !sanityCheck(fn, reporter) {
 		panic("SanityCheck failed")
 	}
 }
@@ -344,3 +344,32 @@ func (s *sanity) checkFunction(fn *Function) bool {
 	s.fn = nil
 	return !s.insane
 }
+
+// sanityCheckPackage checks invariants of packages upon creation.
+// It does not require that the package is built.
+// Unlike sanityCheck (for functions), it just panics at the first error.
+func sanityCheckPackage(pkg *Package) {
+	for name, mem := range pkg.Members {
+		if name != mem.Name() {
+			panic(fmt.Sprintf("%s: %T.Name() = %s, want %s",
+				pkg.Object.Path(), mem, mem.Name(), name))
+		}
+		obj := mem.Object()
+		if obj == nil {
+			// This check is sound because fields
+			// {Global,Function}.object have type
+			// types.Object.  (If they were declared as
+			// *types.{Var,Func}, we'd have a non-empty
+			// interface containing a nil pointer.)
+
+			continue // not all members have typechecker objects
+		}
+		if obj.Name() != name {
+			panic(fmt.Sprintf("%s: %T.Object().Name() = %s, want %s",
+				pkg.Object.Path(), mem, obj.Name(), name))
+		}
+		if obj.Pos() != mem.Pos() {
+			panic(fmt.Sprintf("%s Pos=%d obj.Pos=%d", mem, mem.Pos(), obj.Pos()))
+		}
+	}
+}

ssa/ssa.go

@@ -55,11 +55,12 @@ type Package struct {
 // const, var, func and type declarations respectively.
 //
 type Member interface {
-	Name() string       // the declared name of the package member
-	String() string     // human-readable information about the value
-	Pos() token.Pos     // position of member's declaration, if known
-	Type() types.Type   // the type of the package member
-	Token() token.Token // token.{VAR,FUNC,CONST,TYPE}
+	Name() string         // declared name of the package member
+	String() string       // package-qualified name of the package member
+	Object() types.Object // typechecker's object for this member, if any
+	Pos() token.Pos       // position of member's declaration, if known
+	Type() types.Type     // type of the package member
+	Token() token.Token   // token.{VAR,FUNC,CONST,TYPE}
 }
 
 // An Id identifies the name of a field of a struct type, or the name
@@ -96,7 +97,7 @@ type MethodSet map[Id]*Function
 // Type() returns a *types.Named.
 //
 type Type struct {
-	Object *types.TypeName
+	object *types.TypeName
 }
 
 // A Constant is a Member of Package representing a package-level
@@ -109,9 +110,9 @@ type Type struct {
 // it augments with the name and position of its 'const' declaration.
 //
 type Constant struct {
-	name  string
-	Value *Literal
-	pos   token.Pos
+	object *types.Const
+	Value  *Literal
+	pos    token.Pos
 }
 
 // An SSA value that can be referenced by an instruction.
@@ -266,6 +267,7 @@ type Instruction interface {
 //
 type Function struct {
 	name      string
+	object    types.Object // a *types.Func; may be nil for init, wrappers, etc.
 	Signature *types.Signature
 	pos       token.Pos
 
@@ -395,9 +397,10 @@ type Literal struct {
 // identifier.
 //
 type Global struct {
-	name string
-	typ  types.Type
-	pos  token.Pos
+	name   string
+	object types.Object // a *types.Var; may be nil for synthetics e.g. init$guard
+	typ    types.Type
+	pos    token.Pos
 
 	Pkg *Package
 
@@ -1315,12 +1318,14 @@ func (v *Global) Name() string            { return v.name }
 func (v *Global) Pos() token.Pos          { return v.pos }
 func (*Global) Referrers() *[]Instruction { return nil }
 func (v *Global) Token() token.Token      { return token.VAR }
+func (v *Global) Object() types.Object    { return v.object }
 
 func (v *Function) Name() string            { return v.name }
 func (v *Function) Type() types.Type        { return v.Signature }
 func (v *Function) Pos() token.Pos          { return v.pos }
 func (*Function) Referrers() *[]Instruction { return nil }
 func (v *Function) Token() token.Token      { return token.FUNC }
+func (v *Function) Object() types.Object    { return v.object }
 
 func (v *Parameter) Type() types.Type          { return v.typ }
 func (v *Parameter) Name() string              { return v.name }
@@ -1346,17 +1351,23 @@ func (v *anInstruction) Parent() *Function          { return v.block.parent }
 func (v *anInstruction) Block() *BasicBlock         { return v.block }
 func (v *anInstruction) SetBlock(block *BasicBlock) { v.block = block }
 
-func (t *Type) Name() string       { return t.Object.Name() }
-func (t *Type) Pos() token.Pos     { return t.Object.Pos() }
-func (t *Type) String() string     { return t.Name() }
-func (t *Type) Type() types.Type   { return t.Object.Type() }
-func (t *Type) Token() token.Token { return token.TYPE }
+func (t *Type) Name() string         { return t.object.Name() }
+func (t *Type) Pos() token.Pos       { return t.object.Pos() }
+func (t *Type) Type() types.Type     { return t.object.Type() }
+func (t *Type) Token() token.Token   { return token.TYPE }
+func (t *Type) Object() types.Object { return t.object }
+func (t *Type) String() string {
+	return fmt.Sprintf("%s.%s", t.object.Pkg().Path(), t.object.Name())
+}
 
-func (c *Constant) Name() string       { return c.name }
-func (c *Constant) Pos() token.Pos     { return c.pos }
-func (c *Constant) String() string     { return c.Name() }
-func (c *Constant) Type() types.Type   { return c.Value.Type() }
-func (c *Constant) Token() token.Token { return token.CONST }
+func (c *Constant) Name() string   { return c.object.Name() }
+func (c *Constant) Pos() token.Pos { return c.object.Pos() }
+func (c *Constant) String() string {
+	return fmt.Sprintf("%s.%s", c.object.Pkg().Path(), c.object.Name())
+}
+func (c *Constant) Type() types.Type     { return c.object.Type() }
+func (c *Constant) Token() token.Token   { return token.CONST }
+func (c *Constant) Object() types.Object { return c.object }
 
 // Func returns the package-level function of the specified name,
 // or nil if not found.