compiler: integrate ir package into compiler package

The ir package has long lost its original purpose (which was doing some
analysis and optimization on the Go SSA directly). There is very little
of it left, which is best integrated directly in the compiler package to
avoid unnecessary abstraction.

Makefile

@@ -111,7 +111,7 @@ endif
 clean:
 	@rm -rf build
 
-FMT_PATHS = ./*.go builder cgo compiler compiler/testdata interp ir loader src/device/arm src/examples src/machine src/os src/reflect src/runtime src/sync src/syscall src/internal/reflectlite transform
+FMT_PATHS = ./*.go builder cgo compiler compiler/testdata interp loader src/device/arm src/examples src/machine src/os src/reflect src/runtime src/sync src/syscall src/internal/reflectlite transform
 fmt:
 	@gofmt -l -w $(FMT_PATHS)
 fmt-check:

compiler/calls.go

@@ -35,7 +35,7 @@ const (
 
 // createCall creates a new call to runtime.<fnName> with the given arguments.
 func (b *builder) createRuntimeCall(fnName string, args []llvm.Value, name string) llvm.Value {
-	fn := b.ir.Program.ImportedPackage("runtime").Members[fnName].(*ssa.Function)
+	fn := b.program.ImportedPackage("runtime").Members[fnName].(*ssa.Function)
 	llvmFn := b.getFunction(fn)
 	if llvmFn.IsNil() {
 		panic("trying to call non-existent function: " + fn.RelString(nil))

compiler/compiler.go

@@ -18,7 +18,6 @@ import (
 	"github.com/tinygo-org/tinygo/compileopts"
 	"github.com/tinygo-org/tinygo/compiler/llvmutil"
 	"github.com/tinygo-org/tinygo/goenv"
-	"github.com/tinygo-org/tinygo/ir"
 	"github.com/tinygo-org/tinygo/loader"
 	"golang.org/x/tools/go/ssa"
 	"tinygo.org/x/go-llvm"
@@ -52,7 +51,7 @@ type compilerContext struct {
 	i8ptrType        llvm.Type // for convenience
 	funcPtrAddrSpace int
 	uintptrType      llvm.Type
-	ir               *ir.Program
+	program          *ssa.Program
 	diagnostics      []error
 	astComments      map[string]*ast.CommentGroup
 }
@@ -245,7 +244,8 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 		return c.mod, nil, []error{err}
 	}
 
-	c.ir = ir.NewProgram(lprogram, pkgName)
+	c.program = lprogram.LoadSSA()
+	c.program.Build()
 
 	// Initialize debug information.
 	if c.Debug() {
@@ -264,7 +264,7 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 	// TODO: lazily create runtime types in getLLVMRuntimeType when they are
 	// needed. Eventually this will be required anyway, when packages are
 	// compiled independently (and the runtime types are not available).
-	for _, member := range c.ir.Program.ImportedPackage("runtime").Members {
+	for _, member := range c.program.ImportedPackage("runtime").Members {
 		if member, ok := member.(*ssa.Type); ok {
 			if typ, ok := member.Type().(*types.Named); ok {
 				if _, ok := typ.Underlying().(*types.Struct); ok {
@@ -276,11 +276,13 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 
 	// Predeclare the runtime.alloc function, which is used by the wordpack
 	// functionality.
-	c.getFunction(c.ir.Program.ImportedPackage("runtime").Members["alloc"].(*ssa.Function))
+	c.getFunction(c.program.ImportedPackage("runtime").Members["alloc"].(*ssa.Function))
+
+	sortedPackages := sortPackages(c.program, pkgName)
 
 	// Find package initializers.
 	var initFuncs []llvm.Value
-	for _, pkg := range c.ir.Packages() {
+	for _, pkg := range sortedPackages {
 		for _, member := range pkg.Members {
 			switch member := member.(type) {
 			case *ssa.Function:
@@ -294,19 +296,19 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 	// Add definitions to declarations.
 	irbuilder := c.ctx.NewBuilder()
 	defer irbuilder.Dispose()
-	for _, pkg := range c.ir.Packages() {
+	for _, pkg := range sortedPackages {
 		c.createPackage(pkg, irbuilder)
 	}
 
 	// After all packages are imported, add a synthetic initializer function
 	// that calls the initializer of each package.
-	initFn := c.ir.Program.ImportedPackage("runtime").Members["initAll"].(*ssa.Function)
+	initFn := c.program.ImportedPackage("runtime").Members["initAll"].(*ssa.Function)
 	llvmInitFn := c.getFunction(initFn)
 	llvmInitFn.SetLinkage(llvm.InternalLinkage)
 	llvmInitFn.SetUnnamedAddr(true)
 	if c.Debug() {
 		difunc := c.attachDebugInfo(initFn)
-		pos := c.ir.Program.Fset.Position(initFn.Pos())
+		pos := c.program.Fset.Position(initFn.Pos())
 		irbuilder.SetCurrentDebugLocation(uint(pos.Line), uint(pos.Column), difunc, llvm.Metadata{})
 	}
 	block := c.ctx.AddBasicBlock(llvmInitFn, "entry")
@@ -318,7 +320,7 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 
 	// Conserve for goroutine lowering. Without marking these as external, they
 	// would be optimized away.
-	realMain := c.mod.NamedFunction(c.ir.MainPkg().Pkg.Path() + ".main")
+	realMain := c.mod.NamedFunction(pkgName + ".main")
 	realMain.SetLinkage(llvm.ExternalLinkage) // keep alive until goroutine lowering
 
 	// Replace callMain placeholder with actual main function.
@@ -374,7 +376,7 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 
 	// Gather the list of (C) file paths that should be included in the build.
 	var extraFiles []string
-	for _, pkg := range c.ir.LoaderProgram.Sorted() {
+	for _, pkg := range lprogram.Sorted() {
 		for _, file := range pkg.CFiles {
 			extraFiles = append(extraFiles, filepath.Join(pkg.Package.Dir, file))
 		}
@@ -383,6 +385,73 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 	return c.mod, extraFiles, c.diagnostics
 }
 
+// sortPackages returns a list of all packages, sorted by import order.
+func sortPackages(program *ssa.Program, mainPath string) []*ssa.Package {
+	// Find the main package, which is a bit difficult when running a .go file
+	// directly.
+	mainPkg := program.ImportedPackage(mainPath)
+	if mainPkg == nil {
+		for _, pkgInfo := range program.AllPackages() {
+			if pkgInfo.Pkg.Name() == "main" {
+				if mainPkg != nil {
+					panic("more than one main package found")
+				}
+				mainPkg = pkgInfo
+			}
+		}
+	}
+	if mainPkg == nil {
+		panic("could not find main package")
+	}
+
+	packageList := []*ssa.Package{}
+	packageSet := map[string]struct{}{}
+	worklist := []string{"runtime", mainPath}
+	for len(worklist) != 0 {
+		pkgPath := worklist[0]
+		var pkg *ssa.Package
+		if pkgPath == mainPath {
+			pkg = mainPkg // necessary for compiling individual .go files
+		} else {
+			pkg = program.ImportedPackage(pkgPath)
+		}
+		if pkg == nil {
+			// Non-SSA package (e.g. cgo).
+			packageSet[pkgPath] = struct{}{}
+			worklist = worklist[1:]
+			continue
+		}
+		if _, ok := packageSet[pkgPath]; ok {
+			// Package already in the final package list.
+			worklist = worklist[1:]
+			continue
+		}
+
+		unsatisfiedImports := make([]string, 0)
+		imports := pkg.Pkg.Imports()
+		for _, pkg := range imports {
+			if _, ok := packageSet[pkg.Path()]; ok {
+				continue
+			}
+			unsatisfiedImports = append(unsatisfiedImports, pkg.Path())
+		}
+		if len(unsatisfiedImports) == 0 {
+			// All dependencies of this package are satisfied, so add this
+			// package to the list.
+			packageList = append(packageList, pkg)
+			packageSet[pkgPath] = struct{}{}
+			worklist = worklist[1:]
+		} else {
+			// Prepend all dependencies to the worklist and reconsider this
+			// package (by not removing it from the worklist). At that point, it
+			// must be possible to add it to packageList.
+			worklist = append(unsatisfiedImports, worklist...)
+		}
+	}
+
+	return packageList
+}
+
 // getLLVMRuntimeType obtains a named type from the runtime package and returns
 // it as a LLVM type, creating it if necessary. It is a shorthand for
 // getLLVMType(getRuntimeType(name)).
@@ -576,11 +645,11 @@ func (c *compilerContext) createDIType(typ types.Type) llvm.Metadata {
 			Encoding:   encoding,
 		})
 	case *types.Chan:
-		return c.getDIType(types.NewPointer(c.ir.Program.ImportedPackage("runtime").Members["channel"].(*ssa.Type).Type()))
+		return c.getDIType(types.NewPointer(c.program.ImportedPackage("runtime").Members["channel"].(*ssa.Type).Type()))
 	case *types.Interface:
-		return c.getDIType(c.ir.Program.ImportedPackage("runtime").Members["_interface"].(*ssa.Type).Type())
+		return c.getDIType(c.program.ImportedPackage("runtime").Members["_interface"].(*ssa.Type).Type())
 	case *types.Map:
-		return c.getDIType(types.NewPointer(c.ir.Program.ImportedPackage("runtime").Members["hashmap"].(*ssa.Type).Type()))
+		return c.getDIType(types.NewPointer(c.program.ImportedPackage("runtime").Members["hashmap"].(*ssa.Type).Type()))
 	case *types.Named:
 		return c.dibuilder.CreateTypedef(llvm.DITypedef{
 			Type: c.getDIType(typ.Underlying()),
@@ -688,7 +757,7 @@ func (b *builder) getLocalVariable(variable *types.Var) llvm.Metadata {
 		return dilocal
 	}
 
-	pos := b.ir.Program.Fset.Position(variable.Pos())
+	pos := b.program.Fset.Position(variable.Pos())
 
 	// Check whether this is a function parameter.
 	for i, param := range b.fn.Params {
@@ -722,7 +791,7 @@ func (b *builder) getLocalVariable(variable *types.Var) llvm.Metadata {
 // attachDebugInfo adds debug info to a function declaration. It returns the
 // DISubprogram metadata node.
 func (c *compilerContext) attachDebugInfo(f *ssa.Function) llvm.Metadata {
-	pos := c.ir.Program.Fset.Position(f.Syntax().Pos())
+	pos := c.program.Fset.Position(f.Syntax().Pos())
 	return c.attachDebugInfoRaw(f, c.getFunction(f), "", pos.Filename, pos.Line)
 }
 
@@ -876,7 +945,7 @@ func (c *compilerContext) createFunction(irbuilder llvm.Builder, fn *ssa.Functio
 			// Create debug info file if needed.
 			b.difunc = b.attachDebugInfo(b.fn)
 		}
-		pos := b.ir.Program.Fset.Position(b.fn.Pos())
+		pos := b.program.Fset.Position(b.fn.Pos())
 		b.SetCurrentDebugLocation(uint(pos.Line), uint(pos.Column), b.difunc, llvm.Metadata{})
 	}
 
@@ -978,7 +1047,7 @@ func (c *compilerContext) createFunction(irbuilder llvm.Builder, fn *ssa.Functio
 					continue
 				}
 				dbgVar := b.getLocalVariable(variable)
-				pos := b.ir.Program.Fset.Position(instr.Pos())
+				pos := b.program.Fset.Position(instr.Pos())
 				b.dibuilder.InsertValueAtEnd(b.getValue(instr.X), dbgVar, b.dibuilder.CreateExpression(nil), llvm.DebugLoc{
 					Line:  uint(pos.Line),
 					Col:   uint(pos.Column),
@@ -1032,7 +1101,7 @@ func (c *compilerContext) createFunction(irbuilder llvm.Builder, fn *ssa.Functio
 // particular Go SSA instruction.
 func (b *builder) createInstruction(instr ssa.Instruction) {
 	if b.Debug() {
-		pos := b.ir.Program.Fset.Position(instr.Pos())
+		pos := b.program.Fset.Position(instr.Pos())
 		b.SetCurrentDebugLocation(uint(pos.Line), uint(pos.Column), b.difunc, llvm.Metadata{})
 	}
 

compiler/errors.go

@@ -14,7 +14,7 @@ import (
 // makeError makes it easy to create an error from a token.Pos with a message.
 func (c *compilerContext) makeError(pos token.Pos, msg string) types.Error {
 	return types.Error{
-		Fset: c.ir.Program.Fset,
+		Fset: c.program.Fset,
 		Pos:  pos,
 		Msg:  msg,
 	}

compiler/goroutine.go

@@ -29,7 +29,7 @@ func (b *builder) createGoInstruction(funcPtr llvm.Value, params []llvm.Value, p
 	default:
 		panic("unreachable")
 	}
-	start := b.getFunction(b.ir.Program.ImportedPackage("internal/task").Members["start"].(*ssa.Function))
+	start := b.getFunction(b.program.ImportedPackage("internal/task").Members["start"].(*ssa.Function))
 	b.createCall(start, []llvm.Value{callee, paramBundle, llvm.Undef(b.i8ptrType), llvm.ConstPointerNull(b.i8ptrType)}, "")
 	return llvm.Undef(funcPtr.Type().ElementType().ReturnType())
 }
@@ -75,7 +75,7 @@ func (c *compilerContext) createGoroutineStartWrapper(fn llvm.Value, prefix stri
 		builder.SetInsertPointAtEnd(entry)
 
 		if c.Debug() {
-			pos := c.ir.Program.Fset.Position(pos)
+			pos := c.program.Fset.Position(pos)
 			diFuncType := c.dibuilder.CreateSubroutineType(llvm.DISubroutineType{
 				File:       c.getDIFile(pos.Filename),
 				Parameters: nil, // do not show parameters in debugger
@@ -131,7 +131,7 @@ func (c *compilerContext) createGoroutineStartWrapper(fn llvm.Value, prefix stri
 		builder.SetInsertPointAtEnd(entry)
 
 		if c.Debug() {
-			pos := c.ir.Program.Fset.Position(pos)
+			pos := c.program.Fset.Position(pos)
 			diFuncType := c.dibuilder.CreateSubroutineType(llvm.DISubroutineType{
 				File:       c.getDIFile(pos.Filename),
 				Parameters: nil, // do not show parameters in debugger

compiler/interface.go

@@ -11,7 +11,6 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/tinygo-org/tinygo/ir"
 	"golang.org/x/tools/go/ssa"
 	"tinygo.org/x/go-llvm"
 )
@@ -236,7 +235,7 @@ func (c *compilerContext) getTypeMethodSet(typ types.Type) llvm.Value {
 		return llvm.ConstGEP(global, []llvm.Value{zero, zero})
 	}
 
-	ms := c.ir.Program.MethodSets.MethodSet(typ)
+	ms := c.program.MethodSets.MethodSet(typ)
 	if ms.Len() == 0 {
 		// no methods, so can leave that one out
 		return llvm.ConstPointerNull(llvm.PointerType(c.getLLVMRuntimeType("interfaceMethodInfo"), 0))
@@ -247,7 +246,7 @@ func (c *compilerContext) getTypeMethodSet(typ types.Type) llvm.Value {
 	for i := 0; i < ms.Len(); i++ {
 		method := ms.At(i)
 		signatureGlobal := c.getMethodSignature(method.Obj().(*types.Func))
-		fn := c.ir.Program.MethodValue(method)
+		fn := c.program.MethodValue(method)
 		llvmFn := c.getFunction(fn)
 		if llvmFn.IsNil() {
 			// compiler error, so panic
@@ -311,7 +310,7 @@ func (c *compilerContext) getInterfaceMethodSet(typ types.Type) llvm.Value {
 // external *i8 indicating the indicating the signature of this method. It is
 // used during the interface lowering pass.
 func (c *compilerContext) getMethodSignature(method *types.Func) llvm.Value {
-	signature := ir.MethodSignature(method)
+	signature := methodSignature(method)
 	signatureGlobal := c.mod.NamedGlobal("func " + signature)
 	if signatureGlobal.IsNil() {
 		signatureGlobal = llvm.AddGlobal(c.mod, c.ctx.Int8Type(), "func "+signature)
@@ -489,7 +488,7 @@ func (c *compilerContext) getInterfaceInvokeWrapper(fn *ssa.Function, llvmFn llv
 
 	// add debug info if needed
 	if c.Debug() {
-		pos := c.ir.Program.Fset.Position(fn.Pos())
+		pos := c.program.Fset.Position(fn.Pos())
 		difunc := c.attachDebugInfoRaw(fn, wrapper, "$invoke", pos.Filename, pos.Line)
 		b.SetCurrentDebugLocation(uint(pos.Line), uint(pos.Column), difunc, llvm.Metadata{})
 	}
@@ -522,3 +521,50 @@ func isAnonymous(typ types.Type) bool {
 	}
 	return false
 }
+
+// methodSignature creates a readable version of a method signature (including
+// the function name, excluding the receiver name). This string is used
+// internally to match interfaces and to call the correct method on an
+// interface. Examples:
+//
+//     String() string
+//     Read([]byte) (int, error)
+func methodSignature(method *types.Func) string {
+	return method.Name() + signature(method.Type().(*types.Signature))
+}
+
+// Make a readable version of a function (pointer) signature.
+// Examples:
+//
+//     () string
+//     (string, int) (int, error)
+func signature(sig *types.Signature) string {
+	s := ""
+	if sig.Params().Len() == 0 {
+		s += "()"
+	} else {
+		s += "("
+		for i := 0; i < sig.Params().Len(); i++ {
+			if i > 0 {
+				s += ", "
+			}
+			s += sig.Params().At(i).Type().String()
+		}
+		s += ")"
+	}
+	if sig.Results().Len() == 0 {
+		// keep as-is
+	} else if sig.Results().Len() == 1 {
+		s += " " + sig.Results().At(0).Type().String()
+	} else {
+		s += " ("
+		for i := 0; i < sig.Results().Len(); i++ {
+			if i > 0 {
+				s += ", "
+			}
+			s += sig.Results().At(i).Type().String()
+		}
+		s += ")"
+	}
+	return s
+}

compiler/interrupt.go

@@ -39,7 +39,7 @@ func (b *builder) createInterruptGlobal(instr *ssa.CallCommon) (llvm.Value, erro
 
 	// Create a new global of type runtime/interrupt.handle. Globals of this
 	// type are lowered in the interrupt lowering pass.
-	globalType := b.ir.Program.ImportedPackage("runtime/interrupt").Type("handle").Type()
+	globalType := b.program.ImportedPackage("runtime/interrupt").Type("handle").Type()
 	globalLLVMType := b.getLLVMType(globalType)
 	globalName := "runtime/interrupt.$interrupt" + strconv.FormatInt(id.Int64(), 10)
 	if global := b.mod.NamedGlobal(globalName); !global.IsNil() {
@@ -56,7 +56,7 @@ func (b *builder) createInterruptGlobal(instr *ssa.CallCommon) (llvm.Value, erro
 
 	// Add debug info to the interrupt global.
 	if b.Debug() {
-		pos := b.ir.Program.Fset.Position(instr.Pos())
+		pos := b.program.Fset.Position(instr.Pos())
 		diglobal := b.dibuilder.CreateGlobalVariableExpression(b.getDIFile(pos.Filename), llvm.DIGlobalVariableExpression{
 			Name:        "interrupt" + strconv.FormatInt(id.Int64(), 10),
 			LinkageName: globalName,

compiler/symbol.go

@@ -277,7 +277,7 @@ func (c *compilerContext) getGlobal(g *ssa.Global) llvm.Value {
 			// Add debug info.
 			// TODO: this should be done for every global in the program, not just
 			// the ones that are referenced from some code.
-			pos := c.ir.Program.Fset.Position(g.Pos())
+			pos := c.program.Fset.Position(g.Pos())
 			diglobal := c.dibuilder.CreateGlobalVariableExpression(c.difiles[pos.Filename], llvm.DIGlobalVariableExpression{
 				Name:        g.RelString(nil),
 				LinkageName: info.linkName,

ir/ir.go

@@ -1,151 +0,0 @@
-package ir
-
-import (
-	"go/types"
-
-	"github.com/tinygo-org/tinygo/loader"
-	"golang.org/x/tools/go/ssa"
-)
-
-// This file provides a wrapper around go/ssa values and adds extra
-// functionality to them.
-
-// View on all functions, types, and globals in a program, with analysis
-// results.
-type Program struct {
-	Program       *ssa.Program
-	LoaderProgram *loader.Program
-	mainPkg       *ssa.Package
-	mainPath      string
-}
-
-// Create and initialize a new *Program from a *ssa.Program.
-func NewProgram(lprogram *loader.Program, mainPath string) *Program {
-	program := lprogram.LoadSSA()
-	program.Build()
-
-	// Find the main package, which is a bit difficult when running a .go file
-	// directly.
-	mainPkg := program.ImportedPackage(mainPath)
-	if mainPkg == nil {
-		for _, pkgInfo := range program.AllPackages() {
-			if pkgInfo.Pkg.Name() == "main" {
-				if mainPkg != nil {
-					panic("more than one main package found")
-				}
-				mainPkg = pkgInfo
-			}
-		}
-	}
-	if mainPkg == nil {
-		panic("could not find main package")
-	}
-
-	return &Program{
-		Program:       program,
-		LoaderProgram: lprogram,
-		mainPkg:       mainPkg,
-		mainPath:      mainPath,
-	}
-}
-
-// Packages returns a list of all packages, sorted by import order.
-func (p *Program) Packages() []*ssa.Package {
-	packageList := []*ssa.Package{}
-	packageSet := map[string]struct{}{}
-	worklist := []string{"runtime", p.mainPath}
-	for len(worklist) != 0 {
-		pkgPath := worklist[0]
-		var pkg *ssa.Package
-		if pkgPath == p.mainPath {
-			pkg = p.mainPkg // necessary for compiling individual .go files
-		} else {
-			pkg = p.Program.ImportedPackage(pkgPath)
-		}
-		if pkg == nil {
-			// Non-SSA package (e.g. cgo).
-			packageSet[pkgPath] = struct{}{}
-			worklist = worklist[1:]
-			continue
-		}
-		if _, ok := packageSet[pkgPath]; ok {
-			// Package already in the final package list.
-			worklist = worklist[1:]
-			continue
-		}
-
-		unsatisfiedImports := make([]string, 0)
-		imports := pkg.Pkg.Imports()
-		for _, pkg := range imports {
-			if _, ok := packageSet[pkg.Path()]; ok {
-				continue
-			}
-			unsatisfiedImports = append(unsatisfiedImports, pkg.Path())
-		}
-		if len(unsatisfiedImports) == 0 {
-			// All dependencies of this package are satisfied, so add this
-			// package to the list.
-			packageList = append(packageList, pkg)
-			packageSet[pkgPath] = struct{}{}
-			worklist = worklist[1:]
-		} else {
-			// Prepend all dependencies to the worklist and reconsider this
-			// package (by not removing it from the worklist). At that point, it
-			// must be possible to add it to packageList.
-			worklist = append(unsatisfiedImports, worklist...)
-		}
-	}
-
-	return packageList
-}
-
-func (p *Program) MainPkg() *ssa.Package {
-	return p.mainPkg
-}
-
-// MethodSignature creates a readable version of a method signature (including
-// the function name, excluding the receiver name). This string is used
-// internally to match interfaces and to call the correct method on an
-// interface. Examples:
-//
-//     String() string
-//     Read([]byte) (int, error)
-func MethodSignature(method *types.Func) string {
-	return method.Name() + signature(method.Type().(*types.Signature))
-}
-
-// Make a readable version of a function (pointer) signature.
-// Examples:
-//
-//     () string
-//     (string, int) (int, error)
-func signature(sig *types.Signature) string {
-	s := ""
-	if sig.Params().Len() == 0 {
-		s += "()"
-	} else {
-		s += "("
-		for i := 0; i < sig.Params().Len(); i++ {
-			if i > 0 {
-				s += ", "
-			}
-			s += sig.Params().At(i).Type().String()
-		}
-		s += ")"
-	}
-	if sig.Results().Len() == 0 {
-		// keep as-is
-	} else if sig.Results().Len() == 1 {
-		s += " " + sig.Results().At(0).Type().String()
-	} else {
-		s += " ("
-		for i := 0; i < sig.Results().Len(); i++ {
-			if i > 0 {
-				s += ", "
-			}
-			s += sig.Results().At(i).Type().String()
-		}
-		s += ")"
-	}
-	return s
-}