Merge pull request #100 from xushiwei/q

llgo/ssa: vkFuncDecl/vkFuncPtr/vkClosure

cl/_testrt/cvar/in.go

@@ -0,0 +1,19 @@
+package main
+
+import _ "unsafe"
+
+//go:linkname barX _bar_x
+var barX struct {
+	Arr       [16]int8
+	Callbacks [2]func()
+}
+
+//go:linkname barY _bar_y
+var barY struct {
+	Arr [16]int8
+}
+
+func main() {
+	_ = barX
+	_ = barY
+}

cl/_testrt/cvar/out.ll

@@ -0,0 +1,30 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+@_bar_x = external global ptr
+@_bar_y = external global ptr
+@"main.init$guard" = global ptr null
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define void @main() {
+_llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  %0 = load { [16 x i8], [2 x ptr] }, ptr @_bar_x, align 8
+  %1 = load { [16 x i8] }, ptr @_bar_y, align 1
+  ret void
+}
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()

cl/_testrt/gblarray/out.ll

@@ -1,7 +1,8 @@
 ; ModuleID = 'main'
 source_filename = "main"
 
-%"github.com/goplus/llgo/internal/abi.Type" = type { i64, i64, i32, i8, i8, i8, i8, ptr, ptr, i32, i32 }
+%"github.com/goplus/llgo/internal/abi.Type" = type { i64, i64, i32, i8, i8, i8, i8, %"github.com/goplus/llgo/internal/runtime.Closure", ptr, i32, i32 }
+%"github.com/goplus/llgo/internal/runtime.Closure" = type { ptr, ptr }
 
 @main.basicTypes = global ptr null
 @"main.init$guard" = global ptr null

cl/_testrt/qsort/in.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/internal/runtime/c"
+)
+
+//go:linkname qsort C.qsort
+func qsort(base c.Pointer, count, elem uintptr, compar func(a, b c.Pointer) c.Int)
+
+func main() {
+	a := [...]int{100, 8, 23, 2, 7}
+	qsort(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	})
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}

cl/_testrt/qsort/out.ll

@@ -0,0 +1,64 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+@"main.init$guard" = global ptr null
+@0 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define void @main() {
+_llgo_0:
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  %0 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 40)
+  %1 = getelementptr inbounds i64, ptr %0, i64 0
+  %2 = getelementptr inbounds i64, ptr %0, i64 1
+  %3 = getelementptr inbounds i64, ptr %0, i64 2
+  %4 = getelementptr inbounds i64, ptr %0, i64 3
+  %5 = getelementptr inbounds i64, ptr %0, i64 4
+  store i64 100, ptr %1, align 4
+  store i64 8, ptr %2, align 4
+  store i64 23, ptr %3, align 4
+  store i64 2, ptr %4, align 4
+  store i64 7, ptr %5, align 4
+  %6 = getelementptr inbounds i64, ptr %0, i64 0
+  call void @qsort(ptr %6, i64 5, i64 8, ptr @"main.main$1")
+  %7 = load [5 x i64], ptr %0, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %8 = phi i64 [ -1, %_llgo_0 ], [ %9, %_llgo_2 ]
+  %9 = add i64 %8, 1
+  %10 = icmp slt i64 %9, 5
+  br i1 %10, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %11 = getelementptr inbounds i64, ptr %0, i64 %9
+  %12 = load i64, ptr %11, align 4
+  %13 = call i32 (ptr, ...) @printf(ptr @0, i64 %12)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+declare void @qsort(ptr, i64, i64, ptr)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64)
+
+declare i32 @"main.main$1"(ptr, ptr)
+
+declare i32 @printf(ptr, ...)

cl/builtin_test.go

@@ -25,6 +25,18 @@ import (
 	"golang.org/x/tools/go/ssa"
 )
 
+func TestErrCompileInstrOrValue(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Fatal("compileInstrOrValue: no error?")
+		}
+	}()
+	ctx := &context{
+		bvals: make(map[ssa.Value]llssa.Expr),
+	}
+	ctx.compileInstrOrValue(nil, &ssa.Call{}, true)
+}
+
 func TestErrAdvance(t *testing.T) {
 	defer func() {
 		if r := recover(); r == nil {

cl/compile.go

@@ -177,15 +177,18 @@ func (p *context) compileMethods(pkg llssa.Package, typ types.Type) {
 // Global variable.
 func (p *context) compileGlobal(pkg llssa.Package, gbl *ssa.Global) {
 	typ := gbl.Type()
-	name, isDef := p.varName(gbl.Pkg.Pkg, gbl)
+	name, vtype := p.varName(gbl.Pkg.Pkg, gbl)
 	if ignoreName(name) || checkCgo(gbl.Name()) {
 		return
 	}
 	if debugInstr {
 		log.Println("==> NewVar", name, typ)
 	}
+	if vtype == cVar {
+		typ = llssa.CType(typ)
+	}
 	g := pkg.NewVar(name, typ)
-	if isDef {
+	if vtype == goVar {
 		g.Init(p.prog.Null(g.Type))
 	}
 }
@@ -200,6 +203,9 @@ func (p *context) compileFunc(pkg llssa.Package, pkgTypes *types.Package, f *ssa
 	if debugInstr {
 		log.Println("==> NewFunc", name, "type:", sig.Recv(), sig)
 	}
+	if ftype == cFunc {
+		sig = llssa.CFuncDecl(sig)
+	}
 	fn := pkg.NewFunc(name, sig)
 	p.inits = append(p.inits, func() {
 		p.fn = fn
@@ -581,14 +587,11 @@ func (p *context) compileValue(b llssa.Builder, v ssa.Value) llssa.Expr {
 			}
 		}
 	case *ssa.Function:
-		panic("unreachable")
+		fn, ftype := p.funcOf(v)
-		/*
+		if ftype >= llgoInstrBase {
-			fn, ftype := p.funcOf(v)
+			panic("can't use llgo instruction as a value")
-			if ftype >= llgoInstrBase {
+		}
-				panic("can't use llgo instruction as a value")
+		return fn.Expr
-			}
-			return fn.Expr
-		*/
 	case *ssa.Global:
 		g := p.varOf(v)
 		return g.Expr

cl/import.go

@@ -220,12 +220,18 @@ func (p *context) funcName(pkg *types.Package, fn *ssa.Function, ignore bool) (s
 	return name, goFunc
 }
 
-func (p *context) varName(pkg *types.Package, v *ssa.Global) (vName string, isDef bool) {
+const (
+	ignoredVar = iota
+	goVar
+	cVar
+)
+
+func (p *context) varName(pkg *types.Package, v *ssa.Global) (vName string, vtype int) {
 	name := llssa.FullName(pkg, v.Name())
 	if v, ok := p.link[name]; ok {
-		return v, false
+		return v, cVar
 	}
-	return name, true
+	return name, goVar
 }
 
 // funcOf returns a function by name and set ftype = goFunc, cFunc, etc.

internal/abi/llgo_autogen.ll

@@ -2,13 +2,14 @@
 source_filename = "github.com/goplus/llgo/internal/abi"
 
 %"github.com/goplus/llgo/internal/abi.ArrayType" = type { %"github.com/goplus/llgo/internal/abi.Type", ptr, ptr, i64 }
-%"github.com/goplus/llgo/internal/abi.Type" = type { i64, i64, i32, i8, i8, i8, i8, ptr, ptr, i32, i32 }
+%"github.com/goplus/llgo/internal/abi.Type" = type { i64, i64, i32, i8, i8, i8, i8, %"github.com/goplus/llgo/internal/runtime.Closure", ptr, i32, i32 }
+%"github.com/goplus/llgo/internal/runtime.Closure" = type { ptr, ptr }
 %"github.com/goplus/llgo/internal/abi.ChanType" = type { %"github.com/goplus/llgo/internal/abi.Type", ptr, i64 }
 %"github.com/goplus/llgo/internal/abi.FuncType" = type { %"github.com/goplus/llgo/internal/abi.Type", i16, i16 }
 %"github.com/goplus/llgo/internal/abi.InterfaceType" = type { %"github.com/goplus/llgo/internal/abi.Type", %"github.com/goplus/llgo/internal/abi.Name", %"github.com/goplus/llgo/internal/runtime.Slice" }
 %"github.com/goplus/llgo/internal/abi.Name" = type { ptr }
 %"github.com/goplus/llgo/internal/runtime.Slice" = type { ptr, i64, i64 }
-%"github.com/goplus/llgo/internal/abi.MapType" = type { %"github.com/goplus/llgo/internal/abi.Type", ptr, ptr, ptr, ptr, i8, i8, i16, i32 }
+%"github.com/goplus/llgo/internal/abi.MapType" = type { %"github.com/goplus/llgo/internal/abi.Type", ptr, ptr, ptr, %"github.com/goplus/llgo/internal/runtime.Closure", i8, i8, i16, i32 }
 %"github.com/goplus/llgo/internal/abi.PtrType" = type { %"github.com/goplus/llgo/internal/abi.Type", ptr }
 %"github.com/goplus/llgo/internal/abi.SliceType" = type { %"github.com/goplus/llgo/internal/abi.Type", ptr }
 %"github.com/goplus/llgo/internal/abi.StructType" = type { %"github.com/goplus/llgo/internal/abi.Type", %"github.com/goplus/llgo/internal/abi.Name", %"github.com/goplus/llgo/internal/runtime.Slice" }

internal/aliases/aliases.go

@@ -0,0 +1,32 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package aliases
+
+import (
+	"go/token"
+	"go/types"
+)
+
+// Package aliases defines backward compatible shims
+// for the types.Alias type representation added in 1.22.
+// This defines placeholders for x/tools until 1.26.
+
+// NewAlias creates a new TypeName in Package pkg that
+// is an alias for the type rhs.
+//
+// The enabled parameter determines whether the resulting [TypeName]'s
+// type is an [types.Alias]. Its value must be the result of a call to
+// [Enabled], which computes the effective value of
+// GODEBUG=gotypesalias=... by invoking the type checker. The Enabled
+// function is expensive and should be called once per task (e.g.
+// package import), not once per call to NewAlias.
+func NewAlias(enabled bool, pos token.Pos, pkg *types.Package, name string, rhs types.Type) *types.TypeName {
+	if enabled {
+		tname := types.NewTypeName(pos, pkg, name, nil)
+		newAlias(tname, rhs)
+		return tname
+	}
+	return types.NewTypeName(pos, pkg, name, rhs)
+}

internal/aliases/aliases_go121.go

@@ -0,0 +1,31 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.22
+// +build !go1.22
+
+package aliases
+
+import (
+	"go/types"
+)
+
+// Alias is a placeholder for a go/types.Alias for <=1.21.
+// It will never be created by go/types.
+type Alias struct{}
+
+func (*Alias) String() string         { panic("unreachable") }
+func (*Alias) Underlying() types.Type { panic("unreachable") }
+func (*Alias) Obj() *types.TypeName   { panic("unreachable") }
+func Rhs(alias *Alias) types.Type     { panic("unreachable") }
+
+// Unalias returns the type t for go <=1.21.
+func Unalias(t types.Type) types.Type { return t }
+
+func newAlias(name *types.TypeName, rhs types.Type) *Alias { panic("unreachable") }
+
+// Enabled reports whether [NewAlias] should create [types.Alias] types.
+//
+// Before go1.22, this function always returns false.
+func Enabled() bool { return false }

internal/aliases/aliases_go122.go

@@ -0,0 +1,63 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.22
+// +build go1.22
+
+package aliases
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+)
+
+// Alias is an alias of types.Alias.
+type Alias = types.Alias
+
+// Rhs returns the type on the right-hand side of the alias declaration.
+func Rhs(alias *Alias) types.Type {
+	if alias, ok := any(alias).(interface{ Rhs() types.Type }); ok {
+		return alias.Rhs() // go1.23+
+	}
+
+	// go1.22's Alias didn't have the Rhs method,
+	// so Unalias is the best we can do.
+	return Unalias(alias)
+}
+
+// Unalias is a wrapper of types.Unalias.
+func Unalias(t types.Type) types.Type { return types.Unalias(t) }
+
+// newAlias is an internal alias around types.NewAlias.
+// Direct usage is discouraged as the moment.
+// Try to use NewAlias instead.
+func newAlias(tname *types.TypeName, rhs types.Type) *Alias {
+	a := types.NewAlias(tname, rhs)
+	// TODO(go.dev/issue/65455): Remove kludgy workaround to set a.actual as a side-effect.
+	Unalias(a)
+	return a
+}
+
+// Enabled reports whether [NewAlias] should create [types.Alias] types.
+//
+// This function is expensive! Call it sparingly.
+func Enabled() bool {
+	// The only reliable way to compute the answer is to invoke go/types.
+	// We don't parse the GODEBUG environment variable, because
+	// (a) it's tricky to do so in a manner that is consistent
+	//     with the godebug package; in particular, a simple
+	//     substring check is not good enough. The value is a
+	//     rightmost-wins list of options. But more importantly:
+	// (b) it is impossible to detect changes to the effective
+	//     setting caused by os.Setenv("GODEBUG"), as happens in
+	//     many tests. Therefore any attempt to cache the result
+	//     is just incorrect.
+	fset := token.NewFileSet()
+	f, _ := parser.ParseFile(fset, "a.go", "package p; type A = int", 0)
+	pkg, _ := new(types.Config).Check("p", fset, []*ast.File{f}, nil)
+	_, enabled := pkg.Scope().Lookup("A").Type().(*types.Alias)
+	return enabled
+}

internal/runtime/c/c.go

@@ -63,6 +63,9 @@ func Malloc(size uintptr) Pointer
 //go:linkname Memcpy C.memcpy
 func Memcpy(dst, src Pointer, n uintptr) Pointer
 
+//go:linkname Memset C.memset
+func Memset(s Pointer, c Int, n uintptr) Pointer
+
 //go:linkname Printf C.printf
 func Printf(format *Char, __llgo_va_list ...any) Int
 

internal/runtime/llgo_autogen.ll

@@ -4,8 +4,9 @@ source_filename = "github.com/goplus/llgo/internal/runtime"
 %"github.com/goplus/llgo/internal/runtime.String" = type { ptr, i64 }
 %"github.com/goplus/llgo/internal/runtime.iface" = type { ptr, ptr }
 %"github.com/goplus/llgo/internal/runtime.itab" = type { ptr, ptr, i32, [4 x i8], [1 x i64] }
+%"github.com/goplus/llgo/internal/runtime.Closure" = type { ptr, ptr }
 %"github.com/goplus/llgo/internal/runtime.Slice" = type { ptr, i64, i64 }
-%"github.com/goplus/llgo/internal/abi.Type" = type { i64, i64, i32, i8, i8, i8, i8, ptr, ptr, i32, i32 }
+%"github.com/goplus/llgo/internal/abi.Type" = type { i64, i64, i32, i8, i8, i8, i8, %"github.com/goplus/llgo/internal/runtime.Closure", ptr, i32, i32 }
 %"github.com/goplus/llgo/internal/runtime.hmap" = type { i64, i8, i8, i16, i32, ptr, ptr, i64, ptr }
 
 @"github.com/goplus/llgo/internal/runtime.TyAny" = global ptr null
@@ -211,6 +212,17 @@ _llgo_0:
   ret ptr %0
 }
 
+define %"github.com/goplus/llgo/internal/runtime.Closure" @"github.com/goplus/llgo/internal/runtime.NewClosure"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = alloca %"github.com/goplus/llgo/internal/runtime.Closure", align 8
+  %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Closure", ptr %2, i32 0, i32 0
+  %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Closure", ptr %2, i32 0, i32 1
+  store ptr %0, ptr %3, align 8
+  store ptr %1, ptr %4, align 8
+  %5 = load %"github.com/goplus/llgo/internal/runtime.Closure", ptr %2, align 8
+  ret %"github.com/goplus/llgo/internal/runtime.Closure" %5
+}
+
 define %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.NewSlice"(ptr %0, i64 %1, i64 %2) {
 _llgo_0:
   %3 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8

internal/runtime/z_closure.go

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package runtime
+
+import (
+	"unsafe"
+)
+
+// Closure represents a closure.
+type Closure struct {
+	f    unsafe.Pointer
+	data unsafe.Pointer // means no context if data is nil
+}
+
+// NewClosure creates a closure.
+func NewClosure(f, data unsafe.Pointer) Closure {
+	return Closure{f, data}
+}

internal/typeparams/normalize.go

@@ -0,0 +1,218 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typeparams
+
+import (
+	"errors"
+	"fmt"
+	"go/types"
+	"os"
+	"strings"
+)
+
+//go:generate go run copytermlist.go
+
+const debug = false
+
+var ErrEmptyTypeSet = errors.New("empty type set")
+
+// StructuralTerms returns a slice of terms representing the normalized
+// structural type restrictions of a type parameter, if any.
+//
+// Structural type restrictions of a type parameter are created via
+// non-interface types embedded in its constraint interface (directly, or via a
+// chain of interface embeddings). For example, in the declaration
+//
+//	type T[P interface{~int; m()}] int
+//
+// the structural restriction of the type parameter P is ~int.
+//
+// With interface embedding and unions, the specification of structural type
+// restrictions may be arbitrarily complex. For example, consider the
+// following:
+//
+//	type A interface{ ~string|~[]byte }
+//
+//	type B interface{ int|string }
+//
+//	type C interface { ~string|~int }
+//
+//	type T[P interface{ A|B; C }] int
+//
+// In this example, the structural type restriction of P is ~string|int: A|B
+// expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,
+// which when intersected with C (~string|~int) yields ~string|int.
+//
+// StructuralTerms computes these expansions and reductions, producing a
+// "normalized" form of the embeddings. A structural restriction is normalized
+// if it is a single union containing no interface terms, and is minimal in the
+// sense that removing any term changes the set of types satisfying the
+// constraint. It is left as a proof for the reader that, modulo sorting, there
+// is exactly one such normalized form.
+//
+// Because the minimal representation always takes this form, StructuralTerms
+// returns a slice of tilde terms corresponding to the terms of the union in
+// the normalized structural restriction. An error is returned if the
+// constraint interface is invalid, exceeds complexity bounds, or has an empty
+// type set. In the latter case, StructuralTerms returns ErrEmptyTypeSet.
+//
+// StructuralTerms makes no guarantees about the order of terms, except that it
+// is deterministic.
+func StructuralTerms(tparam *types.TypeParam) ([]*types.Term, error) {
+	constraint := tparam.Constraint()
+	if constraint == nil {
+		return nil, fmt.Errorf("%s has nil constraint", tparam)
+	}
+	iface, _ := constraint.Underlying().(*types.Interface)
+	if iface == nil {
+		return nil, fmt.Errorf("constraint is %T, not *types.Interface", constraint.Underlying())
+	}
+	return InterfaceTermSet(iface)
+}
+
+// InterfaceTermSet computes the normalized terms for a constraint interface,
+// returning an error if the term set cannot be computed or is empty. In the
+// latter case, the error will be ErrEmptyTypeSet.
+//
+// See the documentation of StructuralTerms for more information on
+// normalization.
+func InterfaceTermSet(iface *types.Interface) ([]*types.Term, error) {
+	return computeTermSet(iface)
+}
+
+// UnionTermSet computes the normalized terms for a union, returning an error
+// if the term set cannot be computed or is empty. In the latter case, the
+// error will be ErrEmptyTypeSet.
+//
+// See the documentation of StructuralTerms for more information on
+// normalization.
+func UnionTermSet(union *types.Union) ([]*types.Term, error) {
+	return computeTermSet(union)
+}
+
+func computeTermSet(typ types.Type) ([]*types.Term, error) {
+	tset, err := computeTermSetInternal(typ, make(map[types.Type]*termSet), 0)
+	if err != nil {
+		return nil, err
+	}
+	if tset.terms.isEmpty() {
+		return nil, ErrEmptyTypeSet
+	}
+	if tset.terms.isAll() {
+		return nil, nil
+	}
+	var terms []*types.Term
+	for _, term := range tset.terms {
+		terms = append(terms, types.NewTerm(term.tilde, term.typ))
+	}
+	return terms, nil
+}
+
+// A termSet holds the normalized set of terms for a given type.
+//
+// The name termSet is intentionally distinct from 'type set': a type set is
+// all types that implement a type (and includes method restrictions), whereas
+// a term set just represents the structural restrictions on a type.
+type termSet struct {
+	complete bool
+	terms    termlist
+}
+
+func indentf(depth int, format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, strings.Repeat(".", depth)+format+"\n", args...)
+}
+
+func computeTermSetInternal(t types.Type, seen map[types.Type]*termSet, depth int) (res *termSet, err error) {
+	if t == nil {
+		panic("nil type")
+	}
+
+	if debug {
+		indentf(depth, "%s", t.String())
+		defer func() {
+			if err != nil {
+				indentf(depth, "=> %s", err)
+			} else {
+				indentf(depth, "=> %s", res.terms.String())
+			}
+		}()
+	}
+
+	const maxTermCount = 100
+	if tset, ok := seen[t]; ok {
+		if !tset.complete {
+			return nil, fmt.Errorf("cycle detected in the declaration of %s", t)
+		}
+		return tset, nil
+	}
+
+	// Mark the current type as seen to avoid infinite recursion.
+	tset := new(termSet)
+	defer func() {
+		tset.complete = true
+	}()
+	seen[t] = tset
+
+	switch u := t.Underlying().(type) {
+	case *types.Interface:
+		// The term set of an interface is the intersection of the term sets of its
+		// embedded types.
+		tset.terms = allTermlist
+		for i := 0; i < u.NumEmbeddeds(); i++ {
+			embedded := u.EmbeddedType(i)
+			if _, ok := embedded.Underlying().(*types.TypeParam); ok {
+				return nil, fmt.Errorf("invalid embedded type %T", embedded)
+			}
+			tset2, err := computeTermSetInternal(embedded, seen, depth+1)
+			if err != nil {
+				return nil, err
+			}
+			tset.terms = tset.terms.intersect(tset2.terms)
+		}
+	case *types.Union:
+		// The term set of a union is the union of term sets of its terms.
+		tset.terms = nil
+		for i := 0; i < u.Len(); i++ {
+			t := u.Term(i)
+			var terms termlist
+			switch t.Type().Underlying().(type) {
+			case *types.Interface:
+				tset2, err := computeTermSetInternal(t.Type(), seen, depth+1)
+				if err != nil {
+					return nil, err
+				}
+				terms = tset2.terms
+			case *types.TypeParam, *types.Union:
+				// A stand-alone type parameter or union is not permitted as union
+				// term.
+				return nil, fmt.Errorf("invalid union term %T", t)
+			default:
+				if t.Type() == types.Typ[types.Invalid] {
+					continue
+				}
+				terms = termlist{{t.Tilde(), t.Type()}}
+			}
+			tset.terms = tset.terms.union(terms)
+			if len(tset.terms) > maxTermCount {
+				return nil, fmt.Errorf("exceeded max term count %d", maxTermCount)
+			}
+		}
+	case *types.TypeParam:
+		panic("unreachable")
+	default:
+		// For all other types, the term set is just a single non-tilde term
+		// holding the type itself.
+		if u != types.Typ[types.Invalid] {
+			tset.terms = termlist{{false, t}}
+		}
+	}
+	return tset, nil
+}
+
+// under is a facade for the go/types internal function of the same name. It is
+// used by typeterm.go.
+func under(t types.Type) types.Type {
+	return t.Underlying()
+}

internal/typeparams/termlist.go

@@ -0,0 +1,163 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by copytermlist.go DO NOT EDIT.
+
+package typeparams
+
+import (
+	"bytes"
+	"go/types"
+)
+
+// A termlist represents the type set represented by the union
+// t1 ∪ y2 ∪ ... tn of the type sets of the terms t1 to tn.
+// A termlist is in normal form if all terms are disjoint.
+// termlist operations don't require the operands to be in
+// normal form.
+type termlist []*term
+
+// allTermlist represents the set of all types.
+// It is in normal form.
+var allTermlist = termlist{new(term)}
+
+// String prints the termlist exactly (without normalization).
+func (xl termlist) String() string {
+	if len(xl) == 0 {
+		return "∅"
+	}
+	var buf bytes.Buffer
+	for i, x := range xl {
+		if i > 0 {
+			buf.WriteString(" | ")
+		}
+		buf.WriteString(x.String())
+	}
+	return buf.String()
+}
+
+// isEmpty reports whether the termlist xl represents the empty set of types.
+func (xl termlist) isEmpty() bool {
+	// If there's a non-nil term, the entire list is not empty.
+	// If the termlist is in normal form, this requires at most
+	// one iteration.
+	for _, x := range xl {
+		if x != nil {
+			return false
+		}
+	}
+	return true
+}
+
+// isAll reports whether the termlist xl represents the set of all types.
+func (xl termlist) isAll() bool {
+	// If there's a 𝓤 term, the entire list is 𝓤.
+	// If the termlist is in normal form, this requires at most
+	// one iteration.
+	for _, x := range xl {
+		if x != nil && x.typ == nil {
+			return true
+		}
+	}
+	return false
+}
+
+// norm returns the normal form of xl.
+func (xl termlist) norm() termlist {
+	// Quadratic algorithm, but good enough for now.
+	// TODO(gri) fix asymptotic performance
+	used := make([]bool, len(xl))
+	var rl termlist
+	for i, xi := range xl {
+		if xi == nil || used[i] {
+			continue
+		}
+		for j := i + 1; j < len(xl); j++ {
+			xj := xl[j]
+			if xj == nil || used[j] {
+				continue
+			}
+			if u1, u2 := xi.union(xj); u2 == nil {
+				// If we encounter a 𝓤 term, the entire list is 𝓤.
+				// Exit early.
+				// (Note that this is not just an optimization;
+				// if we continue, we may end up with a 𝓤 term
+				// and other terms and the result would not be
+				// in normal form.)
+				if u1.typ == nil {
+					return allTermlist
+				}
+				xi = u1
+				used[j] = true // xj is now unioned into xi - ignore it in future iterations
+			}
+		}
+		rl = append(rl, xi)
+	}
+	return rl
+}
+
+// union returns the union xl ∪ yl.
+func (xl termlist) union(yl termlist) termlist {
+	return append(xl, yl...).norm()
+}
+
+// intersect returns the intersection xl ∩ yl.
+func (xl termlist) intersect(yl termlist) termlist {
+	if xl.isEmpty() || yl.isEmpty() {
+		return nil
+	}
+
+	// Quadratic algorithm, but good enough for now.
+	// TODO(gri) fix asymptotic performance
+	var rl termlist
+	for _, x := range xl {
+		for _, y := range yl {
+			if r := x.intersect(y); r != nil {
+				rl = append(rl, r)
+			}
+		}
+	}
+	return rl.norm()
+}
+
+// equal reports whether xl and yl represent the same type set.
+func (xl termlist) equal(yl termlist) bool {
+	// TODO(gri) this should be more efficient
+	return xl.subsetOf(yl) && yl.subsetOf(xl)
+}
+
+// includes reports whether t ∈ xl.
+func (xl termlist) includes(t types.Type) bool {
+	for _, x := range xl {
+		if x.includes(t) {
+			return true
+		}
+	}
+	return false
+}
+
+// supersetOf reports whether y ⊆ xl.
+func (xl termlist) supersetOf(y *term) bool {
+	for _, x := range xl {
+		if y.subsetOf(x) {
+			return true
+		}
+	}
+	return false
+}
+
+// subsetOf reports whether xl ⊆ yl.
+func (xl termlist) subsetOf(yl termlist) bool {
+	if yl.isEmpty() {
+		return xl.isEmpty()
+	}
+
+	// each term x of xl must be a subset of yl
+	for _, x := range xl {
+		if !yl.supersetOf(x) {
+			return false // x is not a subset yl
+		}
+	}
+	return true
+}

internal/typeparams/typeterm.go

@@ -0,0 +1,169 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by copytermlist.go DO NOT EDIT.
+
+package typeparams
+
+import "go/types"
+
+// A term describes elementary type sets:
+//
+//	 ∅:  (*term)(nil)     == ∅                      // set of no types (empty set)
+//	 𝓤:  &term{}          == 𝓤                      // set of all types (𝓤niverse)
+//	 T:  &term{false, T}  == {T}                    // set of type T
+//	~t:  &term{true, t}   == {t' | under(t') == t}  // set of types with underlying type t
+type term struct {
+	tilde bool // valid if typ != nil
+	typ   types.Type
+}
+
+func (x *term) String() string {
+	switch {
+	case x == nil:
+		return "∅"
+	case x.typ == nil:
+		return "𝓤"
+	case x.tilde:
+		return "~" + x.typ.String()
+	default:
+		return x.typ.String()
+	}
+}
+
+// equal reports whether x and y represent the same type set.
+func (x *term) equal(y *term) bool {
+	// easy cases
+	switch {
+	case x == nil || y == nil:
+		return x == y
+	case x.typ == nil || y.typ == nil:
+		return x.typ == y.typ
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	return x.tilde == y.tilde && types.Identical(x.typ, y.typ)
+}
+
+// union returns the union x ∪ y: zero, one, or two non-nil terms.
+func (x *term) union(y *term) (_, _ *term) {
+	// easy cases
+	switch {
+	case x == nil && y == nil:
+		return nil, nil // ∅ ∪ ∅ == ∅
+	case x == nil:
+		return y, nil // ∅ ∪ y == y
+	case y == nil:
+		return x, nil // x ∪ ∅ == x
+	case x.typ == nil:
+		return x, nil // 𝓤 ∪ y == 𝓤
+	case y.typ == nil:
+		return y, nil // x ∪ 𝓤 == 𝓤
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	if x.disjoint(y) {
+		return x, y // x ∪ y == (x, y) if x ∩ y == ∅
+	}
+	// x.typ == y.typ
+
+	// ~t ∪ ~t == ~t
+	// ~t ∪  T == ~t
+	//  T ∪ ~t == ~t
+	//  T ∪  T ==  T
+	if x.tilde || !y.tilde {
+		return x, nil
+	}
+	return y, nil
+}
+
+// intersect returns the intersection x ∩ y.
+func (x *term) intersect(y *term) *term {
+	// easy cases
+	switch {
+	case x == nil || y == nil:
+		return nil // ∅ ∩ y == ∅ and ∩ ∅ == ∅
+	case x.typ == nil:
+		return y // 𝓤 ∩ y == y
+	case y.typ == nil:
+		return x // x ∩ 𝓤 == x
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	if x.disjoint(y) {
+		return nil // x ∩ y == ∅ if x ∩ y == ∅
+	}
+	// x.typ == y.typ
+
+	// ~t ∩ ~t == ~t
+	// ~t ∩  T ==  T
+	//  T ∩ ~t ==  T
+	//  T ∩  T ==  T
+	if !x.tilde || y.tilde {
+		return x
+	}
+	return y
+}
+
+// includes reports whether t ∈ x.
+func (x *term) includes(t types.Type) bool {
+	// easy cases
+	switch {
+	case x == nil:
+		return false // t ∈ ∅ == false
+	case x.typ == nil:
+		return true // t ∈ 𝓤 == true
+	}
+	// ∅ ⊂ x ⊂ 𝓤
+
+	u := t
+	if x.tilde {
+		u = under(u)
+	}
+	return types.Identical(x.typ, u)
+}
+
+// subsetOf reports whether x ⊆ y.
+func (x *term) subsetOf(y *term) bool {
+	// easy cases
+	switch {
+	case x == nil:
+		return true // ∅ ⊆ y == true
+	case y == nil:
+		return false // x ⊆ ∅ == false since x != ∅
+	case y.typ == nil:
+		return true // x ⊆ 𝓤 == true
+	case x.typ == nil:
+		return false // 𝓤 ⊆ y == false since y != 𝓤
+	}
+	// ∅ ⊂ x, y ⊂ 𝓤
+
+	if x.disjoint(y) {
+		return false // x ⊆ y == false if x ∩ y == ∅
+	}
+	// x.typ == y.typ
+
+	// ~t ⊆ ~t == true
+	// ~t ⊆ T == false
+	//  T ⊆ ~t == true
+	//  T ⊆  T == true
+	return !x.tilde || y.tilde
+}
+
+// disjoint reports whether x ∩ y == ∅.
+// x.typ and y.typ must not be nil.
+func (x *term) disjoint(y *term) bool {
+	if debug && (x.typ == nil || y.typ == nil) {
+		panic("invalid argument(s)")
+	}
+	ux := x.typ
+	if y.tilde {
+		ux = under(ux)
+	}
+	uy := y.typ
+	if x.tilde {
+		uy = under(uy)
+	}
+	return !types.Identical(ux, uy)
+}

internal/typeutil/map.go

@@ -0,0 +1,525 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package typeutil defines various utilities for types, such as Map,
+// a mapping from types.Type to interface{} values.
+package typeutil
+
+import (
+	"bytes"
+	"fmt"
+	"go/types"
+	"reflect"
+
+	"github.com/goplus/llgo/internal/aliases"
+	"github.com/goplus/llgo/internal/typeparams"
+)
+
+// Map is a hash-table-based mapping from types (types.Type) to
+// arbitrary interface{} values.  The concrete types that implement
+// the Type interface are pointers.  Since they are not canonicalized,
+// == cannot be used to check for equivalence, and thus we cannot
+// simply use a Go map.
+//
+// Just as with map[K]V, a nil *Map is a valid empty map.
+//
+// Not thread-safe.
+type Map struct {
+	hasher Hasher             // shared by many Maps
+	table  map[uint32][]entry // maps hash to bucket; entry.key==nil means unused
+	length int                // number of map entries
+}
+
+// entry is an entry (key/value association) in a hash bucket.
+type entry struct {
+	key   types.Type
+	value interface{}
+}
+
+// SetHasher sets the hasher used by Map.
+//
+// All Hashers are functionally equivalent but contain internal state
+// used to cache the results of hashing previously seen types.
+//
+// A single Hasher created by MakeHasher() may be shared among many
+// Maps.  This is recommended if the instances have many keys in
+// common, as it will amortize the cost of hash computation.
+//
+// A Hasher may grow without bound as new types are seen.  Even when a
+// type is deleted from the map, the Hasher never shrinks, since other
+// types in the map may reference the deleted type indirectly.
+//
+// Hashers are not thread-safe, and read-only operations such as
+// Map.Lookup require updates to the hasher, so a full Mutex lock (not a
+// read-lock) is require around all Map operations if a shared
+// hasher is accessed from multiple threads.
+//
+// If SetHasher is not called, the Map will create a private hasher at
+// the first call to Insert.
+func (m *Map) SetHasher(hasher Hasher) {
+	m.hasher = hasher
+}
+
+// Delete removes the entry with the given key, if any.
+// It returns true if the entry was found.
+func (m *Map) Delete(key types.Type) bool {
+	if m != nil && m.table != nil {
+		hash := m.hasher.Hash(key)
+		bucket := m.table[hash]
+		for i, e := range bucket {
+			if e.key != nil && types.Identical(key, e.key) {
+				// We can't compact the bucket as it
+				// would disturb iterators.
+				bucket[i] = entry{}
+				m.length--
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// At returns the map entry for the given key.
+// The result is nil if the entry is not present.
+func (m *Map) At(key types.Type) interface{} {
+	if m != nil && m.table != nil {
+		for _, e := range m.table[m.hasher.Hash(key)] {
+			if e.key != nil && types.Identical(key, e.key) {
+				return e.value
+			}
+		}
+	}
+	return nil
+}
+
+// Set sets the map entry for key to val,
+// and returns the previous entry, if any.
+func (m *Map) Set(key types.Type, value interface{}) (prev interface{}) {
+	if m.table != nil {
+		hash := m.hasher.Hash(key)
+		bucket := m.table[hash]
+		var hole *entry
+		for i, e := range bucket {
+			if e.key == nil {
+				hole = &bucket[i]
+			} else if types.Identical(key, e.key) {
+				prev = e.value
+				bucket[i].value = value
+				return
+			}
+		}
+
+		if hole != nil {
+			*hole = entry{key, value} // overwrite deleted entry
+		} else {
+			m.table[hash] = append(bucket, entry{key, value})
+		}
+	} else {
+		if m.hasher.memo == nil {
+			m.hasher = MakeHasher()
+		}
+		hash := m.hasher.Hash(key)
+		m.table = map[uint32][]entry{hash: {entry{key, value}}}
+	}
+
+	m.length++
+	return
+}
+
+// Len returns the number of map entries.
+func (m *Map) Len() int {
+	if m != nil {
+		return m.length
+	}
+	return 0
+}
+
+// Iterate calls function f on each entry in the map in unspecified order.
+//
+// If f should mutate the map, Iterate provides the same guarantees as
+// Go maps: if f deletes a map entry that Iterate has not yet reached,
+// f will not be invoked for it, but if f inserts a map entry that
+// Iterate has not yet reached, whether or not f will be invoked for
+// it is unspecified.
+func (m *Map) Iterate(f func(key types.Type, value interface{})) {
+	if m != nil {
+		for _, bucket := range m.table {
+			for _, e := range bucket {
+				if e.key != nil {
+					f(e.key, e.value)
+				}
+			}
+		}
+	}
+}
+
+// Keys returns a new slice containing the set of map keys.
+// The order is unspecified.
+func (m *Map) Keys() []types.Type {
+	keys := make([]types.Type, 0, m.Len())
+	m.Iterate(func(key types.Type, _ interface{}) {
+		keys = append(keys, key)
+	})
+	return keys
+}
+
+func (m *Map) toString(values bool) string {
+	if m == nil {
+		return "{}"
+	}
+	var buf bytes.Buffer
+	fmt.Fprint(&buf, "{")
+	sep := ""
+	m.Iterate(func(key types.Type, value interface{}) {
+		fmt.Fprint(&buf, sep)
+		sep = ", "
+		fmt.Fprint(&buf, key)
+		if values {
+			fmt.Fprintf(&buf, ": %q", value)
+		}
+	})
+	fmt.Fprint(&buf, "}")
+	return buf.String()
+}
+
+// String returns a string representation of the map's entries.
+// Values are printed using fmt.Sprintf("%v", v).
+// Order is unspecified.
+func (m *Map) String() string {
+	return m.toString(true)
+}
+
+// KeysString returns a string representation of the map's key set.
+// Order is unspecified.
+func (m *Map) KeysString() string {
+	return m.toString(false)
+}
+
+////////////////////////////////////////////////////////////////////////
+// Hasher
+
+// A Hasher maps each type to its hash value.
+// For efficiency, a hasher uses memoization; thus its memory
+// footprint grows monotonically over time.
+// Hashers are not thread-safe.
+// Hashers have reference semantics.
+// Call MakeHasher to create a Hasher.
+type Hasher struct {
+	memo map[types.Type]uint32
+
+	// ptrMap records pointer identity.
+	ptrMap map[interface{}]uint32
+
+	// sigTParams holds type parameters from the signature being hashed.
+	// Signatures are considered identical modulo renaming of type parameters, so
+	// within the scope of a signature type the identity of the signature's type
+	// parameters is just their index.
+	//
+	// Since the language does not currently support referring to uninstantiated
+	// generic types or functions, and instantiated signatures do not have type
+	// parameter lists, we should never encounter a second non-empty type
+	// parameter list when hashing a generic signature.
+	sigTParams *types.TypeParamList
+}
+
+// MakeHasher returns a new Hasher instance.
+func MakeHasher() Hasher {
+	return Hasher{
+		memo:       make(map[types.Type]uint32),
+		ptrMap:     make(map[interface{}]uint32),
+		sigTParams: nil,
+	}
+}
+
+// Hash computes a hash value for the given type t such that
+// Identical(t, t') => Hash(t) == Hash(t').
+func (h Hasher) Hash(t types.Type) uint32 {
+	hash, ok := h.memo[t]
+	if !ok {
+		hash = h.hashFor(t)
+		h.memo[t] = hash
+	}
+	return hash
+}
+
+// hashString computes the Fowler–Noll–Vo hash of s.
+func hashString(s string) uint32 {
+	var h uint32
+	for i := 0; i < len(s); i++ {
+		h ^= uint32(s[i])
+		h *= 16777619
+	}
+	return h
+}
+
+func HashSig(h Hasher, t *types.Signature) uint32 {
+	var hash uint32 = 9091
+	if t.Variadic() {
+		hash *= 8863
+	}
+
+	// Use a separate hasher for types inside of the signature, where type
+	// parameter identity is modified to be (index, constraint). We must use a
+	// new memo for this hasher as type identity may be affected by this
+	// masking. For example, in func[T any](*T), the identity of *T depends on
+	// whether we are mapping the argument in isolation, or recursively as part
+	// of hashing the signature.
+	//
+	// We should never encounter a generic signature while hashing another
+	// generic signature, but defensively set sigTParams only if h.mask is
+	// unset.
+	tparams := t.TypeParams()
+	if h.sigTParams == nil && tparams.Len() != 0 {
+		h = Hasher{
+			// There may be something more efficient than discarding the existing
+			// memo, but it would require detecting whether types are 'tainted' by
+			// references to type parameters.
+			memo: make(map[types.Type]uint32),
+			// Re-using ptrMap ensures that pointer identity is preserved in this
+			// hasher.
+			ptrMap:     h.ptrMap,
+			sigTParams: tparams,
+		}
+	}
+
+	for i := 0; i < tparams.Len(); i++ {
+		tparam := tparams.At(i)
+		hash += 7 * h.Hash(tparam.Constraint())
+	}
+
+	return hash + 3*h.hashTuple(t.Params()) + 5*h.hashTuple(t.Results())
+}
+
+// hashFor computes the hash of t.
+func (h Hasher) hashFor(t types.Type) uint32 {
+	// See Identical for rationale.
+	switch t := t.(type) {
+	case *types.Basic:
+		return uint32(t.Kind())
+
+	case *aliases.Alias:
+		return h.Hash(t.Underlying())
+
+	case *types.Array:
+		return 9043 + 2*uint32(t.Len()) + 3*h.Hash(t.Elem())
+
+	case *types.Slice:
+		return 9049 + 2*h.Hash(t.Elem())
+
+	case *types.Struct:
+		var hash uint32 = 9059
+		for i, n := 0, t.NumFields(); i < n; i++ {
+			f := t.Field(i)
+			if f.Anonymous() {
+				hash += 8861
+			}
+			hash += hashString(t.Tag(i))
+			hash += hashString(f.Name()) // (ignore f.Pkg)
+			hash += h.Hash(f.Type())
+		}
+		return hash
+
+	case *types.Pointer:
+		return 9067 + 2*h.Hash(t.Elem())
+
+	case *types.Signature:
+		return HashSig(h, t)
+
+	case *types.Union:
+		return h.hashUnion(t)
+
+	case *types.Interface:
+		// Interfaces are identical if they have the same set of methods, with
+		// identical names and types, and they have the same set of type
+		// restrictions. See go/types.identical for more details.
+		var hash uint32 = 9103
+
+		// Hash methods.
+		for i, n := 0, t.NumMethods(); i < n; i++ {
+			// Method order is not significant.
+			// Ignore m.Pkg().
+			m := t.Method(i)
+			// Use shallow hash on method signature to
+			// avoid anonymous interface cycles.
+			hash += 3*hashString(m.Name()) + 5*h.shallowHash(m.Type())
+		}
+
+		// Hash type restrictions.
+		terms, err := typeparams.InterfaceTermSet(t)
+		// if err != nil t has invalid type restrictions.
+		if err == nil {
+			hash += h.hashTermSet(terms)
+		}
+
+		return hash
+
+	case *types.Map:
+		return 9109 + 2*h.Hash(t.Key()) + 3*h.Hash(t.Elem())
+
+	case *types.Chan:
+		return 9127 + 2*uint32(t.Dir()) + 3*h.Hash(t.Elem())
+
+	case *types.Named:
+		hash := h.hashPtr(t.Obj())
+		targs := t.TypeArgs()
+		for i := 0; i < targs.Len(); i++ {
+			targ := targs.At(i)
+			hash += 2 * h.Hash(targ)
+		}
+		return hash
+
+	case *types.TypeParam:
+		return h.hashTypeParam(t)
+
+	case *types.Tuple:
+		return h.hashTuple(t)
+
+	case interface{ Hash(h Hasher) uint32 }:
+		return t.Hash(h)
+	}
+
+	panic(fmt.Sprintf("%T: %v", t, t))
+}
+
+func (h Hasher) hashTuple(tuple *types.Tuple) uint32 {
+	// See go/types.identicalTypes for rationale.
+	n := tuple.Len()
+	hash := 9137 + 2*uint32(n)
+	for i := 0; i < n; i++ {
+		hash += 3 * h.Hash(tuple.At(i).Type())
+	}
+	return hash
+}
+
+func (h Hasher) hashUnion(t *types.Union) uint32 {
+	// Hash type restrictions.
+	terms, err := typeparams.UnionTermSet(t)
+	// if err != nil t has invalid type restrictions. Fall back on a non-zero
+	// hash.
+	if err != nil {
+		return 9151
+	}
+	return h.hashTermSet(terms)
+}
+
+func (h Hasher) hashTermSet(terms []*types.Term) uint32 {
+	hash := 9157 + 2*uint32(len(terms))
+	for _, term := range terms {
+		// term order is not significant.
+		termHash := h.Hash(term.Type())
+		if term.Tilde() {
+			termHash *= 9161
+		}
+		hash += 3 * termHash
+	}
+	return hash
+}
+
+// hashTypeParam returns a hash of the type parameter t, with a hash value
+// depending on whether t is contained in h.sigTParams.
+//
+// If h.sigTParams is set and contains t, then we are in the process of hashing
+// a signature, and the hash value of t must depend only on t's index and
+// constraint: signatures are considered identical modulo type parameter
+// renaming. To avoid infinite recursion, we only hash the type parameter
+// index, and rely on types.Identical to handle signatures where constraints
+// are not identical.
+//
+// Otherwise the hash of t depends only on t's pointer identity.
+func (h Hasher) hashTypeParam(t *types.TypeParam) uint32 {
+	if h.sigTParams != nil {
+		i := t.Index()
+		if i >= 0 && i < h.sigTParams.Len() && t == h.sigTParams.At(i) {
+			return 9173 + 3*uint32(i)
+		}
+	}
+	return h.hashPtr(t.Obj())
+}
+
+// hashPtr hashes the pointer identity of ptr. It uses h.ptrMap to ensure that
+// pointers values are not dependent on the GC.
+func (h Hasher) hashPtr(ptr interface{}) uint32 {
+	if hash, ok := h.ptrMap[ptr]; ok {
+		return hash
+	}
+	hash := uint32(reflect.ValueOf(ptr).Pointer())
+	h.ptrMap[ptr] = hash
+	return hash
+}
+
+// shallowHash computes a hash of t without looking at any of its
+// element Types, to avoid potential anonymous cycles in the types of
+// interface methods.
+//
+// When an unnamed non-empty interface type appears anywhere among the
+// arguments or results of an interface method, there is a potential
+// for endless recursion. Consider:
+//
+//	type X interface { m() []*interface { X } }
+//
+// The problem is that the Methods of the interface in m's result type
+// include m itself; there is no mention of the named type X that
+// might help us break the cycle.
+// (See comment in go/types.identical, case *Interface, for more.)
+func (h Hasher) shallowHash(t types.Type) uint32 {
+	// t is the type of an interface method (Signature),
+	// its params or results (Tuples), or their immediate
+	// elements (mostly Slice, Pointer, Basic, Named),
+	// so there's no need to optimize anything else.
+	switch t := t.(type) {
+	case *aliases.Alias:
+		return h.shallowHash(t.Underlying())
+
+	case *types.Signature:
+		var hash uint32 = 604171
+		if t.Variadic() {
+			hash *= 971767
+		}
+		// The Signature/Tuple recursion is always finite
+		// and invariably shallow.
+		return hash + 1062599*h.shallowHash(t.Params()) + 1282529*h.shallowHash(t.Results())
+
+	case *types.Tuple:
+		n := t.Len()
+		hash := 9137 + 2*uint32(n)
+		for i := 0; i < n; i++ {
+			hash += 53471161 * h.shallowHash(t.At(i).Type())
+		}
+		return hash
+
+	case *types.Basic:
+		return 45212177 * uint32(t.Kind())
+
+	case *types.Array:
+		return 1524181 + 2*uint32(t.Len())
+
+	case *types.Slice:
+		return 2690201
+
+	case *types.Struct:
+		return 3326489
+
+	case *types.Pointer:
+		return 4393139
+
+	case *types.Union:
+		return 562448657
+
+	case *types.Interface:
+		return 2124679 // no recursion here
+
+	case *types.Map:
+		return 9109
+
+	case *types.Chan:
+		return 9127
+
+	case *types.Named:
+		return h.hashPtr(t.Obj())
+
+	case *types.TypeParam:
+		return h.hashPtr(t.Obj())
+	}
+	panic(fmt.Sprintf("shallowHash: %T: %v", t, t))
+}

ssa/expr.go

@@ -979,7 +979,7 @@ func (b Builder) BuiltinCall(fn string, args ...Expr) (ret Expr) {
 			case *types.Slice:
 				return b.InlineCall(b.fn.pkg.rtFunc("SliceLen"), arg)
 			case *types.Basic:
-				if t.Info()&types.IsString != 0 {
+				if t.Kind() == types.String {
 					return b.InlineCall(b.fn.pkg.rtFunc("StringLen"), arg)
 				}
 			}

ssa/package.go

@@ -17,12 +17,11 @@
 package ssa
 
 import (
-	"go/constant"
 	"go/types"
 	"runtime"
 
+	"github.com/goplus/llgo/internal/typeutil"
 	"github.com/goplus/llvm"
-	"golang.org/x/tools/go/types/typeutil"
 )
 
 const (
@@ -116,10 +115,11 @@ type aProgram struct {
 	voidType  llvm.Type
 	voidPtrTy llvm.Type
 
-	rtStringTy llvm.Type
+	rtClosureTy llvm.Type
-	rtIfaceTy  llvm.Type
+	rtStringTy  llvm.Type
-	rtSliceTy  llvm.Type
+	rtIfaceTy   llvm.Type
-	rtMapTy    llvm.Type
+	rtSliceTy   llvm.Type
+	rtMapTy     llvm.Type
 
 	anyTy     Type
 	voidTy    Type
@@ -185,6 +185,13 @@ func (p Program) rtType(name string) Type {
 	return p.Type(p.rtNamed(name))
 }
 
+func (p Program) rtClosure() llvm.Type {
+	if p.rtClosureTy.IsNil() {
+		p.rtClosureTy = p.rtType("Closure").ll
+	}
+	return p.rtClosureTy
+}
+
 func (p Program) rtIface() llvm.Type {
 	if p.rtIfaceTy.IsNil() {
 		p.rtIfaceTy = p.rtType("Interface").ll
@@ -305,10 +312,12 @@ type aPackage struct {
 
 type Package = *aPackage
 
+/*
 // NewConst creates a new named constant.
 func (p Package) NewConst(name string, val constant.Value) NamedConst {
 	return &aNamedConst{}
 }
+*/
 
 // NewVar creates a new global variable.
 func (p Package) NewVar(name string, typ types.Type) Global {
@@ -329,7 +338,7 @@ func (p Package) NewFunc(name string, sig *types.Signature) Function {
 	if v, ok := p.fns[name]; ok {
 		return v
 	}
-	t := p.prog.llvmSignature(sig, false)
+	t := p.prog.llvmFuncDecl(sig)
 	fn := llvm.AddFunction(p.mod, name, t.ll)
 	ret := newFunction(fn, t, p, p.prog)
 	p.fns[name] = ret

ssa/ssa_test.go

@@ -30,6 +30,32 @@ func TestMakeInterface(t *testing.T) {
 }
 */
 
+func TestCvtCType(t *testing.T) {
+	test := func(typ types.Type) {
+		defer func() {
+			if r := recover(); r == nil {
+				t.Log("cvtCType: no error?")
+			}
+		}()
+		cvtCType(typ)
+	}
+	test(types.NewInterfaceType(nil, nil))
+
+	a := types.NewTypeName(0, nil, "a", nil)
+	sig := types.NewSignatureType(nil, nil, nil, nil, nil, false)
+	named := types.NewNamed(a, sig, nil)
+	test(named)
+}
+
+func TestCFuncPtr(t *testing.T) {
+	sig := types.NewSignatureType(nil, nil, nil, nil, nil, false)
+	csig := (*CFuncPtr)(sig)
+	_ = csig.String()
+	if csig.Underlying() != sig {
+		t.Fatal("TestCFuncPtr failed")
+	}
+}
+
 func TestUserdefExpr(t *testing.T) {
 	a := delayExprTy(nil)
 	b := &phisExprTy{}

ssa/type.go

@@ -40,7 +40,9 @@ const (
 	vkString
 	vkBool
 	vkPtr
-	vkFunc
+	vkFuncDecl // func decl
+	vkFuncPtr  // func ptr in C
+	vkClosure  // func ptr in Go
 	vkTuple
 	vkDelayExpr = -1
 	vkPhisExpr  = -2
@@ -48,22 +50,6 @@ const (
 
 // -----------------------------------------------------------------------------
 
-const (
-	NameValist = "__llgo_va_list"
-)
-
-func VArg() *types.Var {
-	return types.NewParam(0, nil, NameValist, types.Typ[types.Invalid])
-}
-
-func IsVArg(arg *types.Var) bool {
-	return arg.Name() == NameValist
-}
-
-func HasVArg(t *types.Tuple, n int) bool {
-	return n > 0 && IsVArg(t.At(n-1))
-}
-
 func indexType(t types.Type) types.Type {
 	switch t := t.(type) {
 	case *types.Slice:
@@ -100,7 +86,7 @@ func methodToFunc(sig *types.Signature) *types.Signature {
 type aType struct {
 	ll   llvm.Type
 	t    types.Type
-	kind valueKind
+	kind valueKind // value kind of llvm.Type
 }
 
 type Type = *aType
@@ -128,9 +114,11 @@ func (p Program) Field(typ Type, i int) Type {
 }
 
 func (p Program) Type(typ types.Type) Type {
+	/* TODO(xsw): no need?
 	if sig, ok := typ.(*types.Signature); ok { // should methodToFunc
 		return p.llvmSignature(sig, true)
 	}
+	*/
 	if v := p.typs.At(typ); v != nil {
 		return v.(Type)
 	}
@@ -139,14 +127,9 @@ func (p Program) Type(typ types.Type) Type {
 	return ret
 }
 
-func (p Program) llvmSignature(sig *types.Signature, isPtr bool) Type {
+func (p Program) llvmFuncDecl(sig *types.Signature) Type {
 	sig = methodToFunc(sig)
-	if v := p.typs.At(sig); v != nil {
+	return p.toLLVMFunc(sig, false, true) // don't save func decl to cache
-		return v.(Type)
-	}
-	ret := p.toLLVMFunc(sig, isPtr)
-	p.typs.Set(sig, ret)
-	return ret
 }
 
 func (p Program) tyVoidPtr() llvm.Type {
@@ -262,6 +245,10 @@ func (p Program) toLLVMType(typ types.Type) Type {
 		return p.toLLVMStruct(t)
 	case *types.Named:
 		return p.toLLVMNamed(t)
+	case *types.Signature:
+		return p.toLLVMFunc(t, false, false)
+	case *CFuncPtr:
+		return p.toLLVMFunc((*types.Signature)(t), true, false)
 	case *types.Array:
 		elem := p.Type(t.Elem())
 		return &aType{llvm.ArrayType(elem.ll, int(t.Len())), typ, vkInvalid}
@@ -307,29 +294,39 @@ func (p Program) toLLVMTypes(t *types.Tuple, n int) (ret []llvm.Type) {
 	return
 }
 
-func (p Program) toLLVMFunc(sig *types.Signature, isPtr bool) Type {
+func (p Program) toLLVMFunc(sig *types.Signature, inC, isDecl bool) Type {
-	tParams := sig.Params()
+	var kind valueKind
-	n := tParams.Len()
+	var ft llvm.Type
-	hasVArg := HasVArg(tParams, n)
+	if isDecl || inC {
-	if hasVArg {
+		tParams := sig.Params()
-		n--
+		n := tParams.Len()
+		hasVArg := HasVArg(tParams, n)
+		if hasVArg {
+			n--
+		}
+		params := p.toLLVMTypes(tParams, n)
+		out := sig.Results()
+		var ret llvm.Type
+		switch nret := out.Len(); nret {
+		case 0:
+			ret = p.tyVoid()
+		case 1:
+			ret = p.Type(out.At(0).Type()).ll
+		default:
+			ret = p.toLLVMTuple(out)
+		}
+		ft = llvm.FunctionType(ret, params, hasVArg)
+		if isDecl {
+			kind = vkFuncDecl
+		} else {
+			ft = llvm.PointerType(ft, 0)
+			kind = vkFuncPtr
+		}
+	} else {
+		ft = p.rtClosure()
+		kind = vkClosure
 	}
-	params := p.toLLVMTypes(tParams, n)
+	return &aType{ft, sig, kind}
-	out := sig.Results()
-	var ret llvm.Type
-	switch nret := out.Len(); nret {
-	case 0:
-		ret = p.tyVoid()
-	case 1:
-		ret = p.Type(out.At(0).Type()).ll
-	default:
-		ret = p.toLLVMTuple(out)
-	}
-	ft := llvm.FunctionType(ret, params, hasVArg)
-	if isPtr {
-		ft = llvm.PointerType(ft, 0)
-	}
-	return &aType{ft, sig, vkFunc}
 }
 
 func (p Program) retType(sig *types.Signature) Type {

ssa/type_c.go

@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ssa
+
+import (
+	"go/types"
+
+	"github.com/goplus/llgo/internal/typeutil"
+)
+
+// -----------------------------------------------------------------------------
+
+const (
+	NameValist = "__llgo_va_list"
+)
+
+func VArg() *types.Var {
+	return types.NewParam(0, nil, NameValist, types.Typ[types.Invalid])
+}
+
+func IsVArg(arg *types.Var) bool {
+	return arg.Name() == NameValist
+}
+
+func HasVArg(t *types.Tuple, n int) bool {
+	return n > 0 && IsVArg(t.At(n-1))
+}
+
+// -----------------------------------------------------------------------------
+
+// CFuncPtr represents a C function pointer.
+type CFuncPtr types.Signature
+
+func (t *CFuncPtr) String() string         { return (*types.Signature)(t).String() }
+func (t *CFuncPtr) Underlying() types.Type { return (*types.Signature)(t) }
+
+func (t *CFuncPtr) Hash(h typeutil.Hasher) uint32 {
+	return typeutil.HashSig(h, (*types.Signature)(t))*13 + 97
+}
+
+// -----------------------------------------------------------------------------
+
+// CType convert a C type into Go.
+func CType(typ types.Type) types.Type {
+	t, _ := cvtCType(typ)
+	return t
+}
+
+// CFuncDecl convert a C function decl into Go signature.
+func CFuncDecl(sig *types.Signature) *types.Signature {
+	hasVArg := sig.Variadic()
+	params, cvt1 := cvtTuple(sig.Params(), hasVArg)
+	results, cvt2 := cvtTuple(sig.Results(), false)
+	if cvt1 || cvt2 {
+		return types.NewSignatureType(nil, nil, nil, params, results, hasVArg)
+	}
+	return sig
+}
+
+func cvtCType(typ types.Type) (types.Type, bool) {
+	switch t := typ.(type) {
+	case *types.Basic:
+	case *types.Pointer:
+		if elem, cvt := cvtCType(t.Elem()); cvt {
+			return types.NewPointer(elem), true
+		}
+	case *types.Struct:
+		return cvtCStruct(t)
+	case *types.Named:
+		if _, cvt := cvtCType(t.Underlying()); cvt {
+			panic("don't define named type")
+		}
+	case *types.Signature:
+		t = CFuncDecl(t)
+		return (*CFuncPtr)(t), true
+	case *types.Array:
+		if elem, cvt := cvtCType(t.Elem()); cvt {
+			return types.NewArray(elem, t.Len()), true
+		}
+	default:
+		panic("unreachable")
+	}
+	return typ, false
+}
+
+func cvtTuple(t *types.Tuple, hasVArg bool) (*types.Tuple, bool) {
+	n := t.Len()
+	vars := make([]*types.Var, n)
+	needcvt := false
+	if hasVArg {
+		n--
+		vars[n] = t.At(n)
+	}
+	for i := 0; i < n; i++ {
+		v := t.At(i)
+		if t, cvt := cvtCType(v.Type()); cvt {
+			v = types.NewParam(v.Pos(), v.Pkg(), v.Name(), t)
+			needcvt = true
+		}
+		vars[i] = v
+	}
+	if needcvt {
+		return types.NewTuple(vars...), true
+	}
+	return t, false
+}
+
+func cvtCStruct(typ *types.Struct) (*types.Struct, bool) {
+	n := typ.NumFields()
+	flds := make([]*types.Var, n)
+	needcvt := false
+	for i := 0; i < n; i++ {
+		f := typ.Field(i)
+		if t, cvt := cvtCType(f.Type()); cvt {
+			f = types.NewField(f.Pos(), f.Pkg(), f.Name(), t, f.Anonymous())
+			needcvt = true
+		}
+		flds[i] = f
+	}
+	if needcvt {
+		return types.NewStruct(flds, nil), true
+	}
+	return typ, false
+}
+
+// -----------------------------------------------------------------------------