diff --git a/ssa/builder.go b/ssa/builder.go
new file mode 100644
index 00000000..3b6ec4ea
--- /dev/null
+++ b/ssa/builder.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 ssa
+
+import (
+	"github.com/goplus/llvm"
+)
+
+type Builder struct {
+	impl llvm.Builder
+}
+
+type BasicBlock struct {
+	impl llvm.BasicBlock
+}
+
+func (p BasicBlock) End() {
+}
diff --git a/ssa/decl.go b/ssa/decl.go
index 4d460dc3..582b909a 100644
--- a/ssa/decl.go
+++ b/ssa/decl.go
@@ -28,14 +28,79 @@ import (
 //
 // NB: a NamedConst is not a Value; it contains a constant Value, which
 // it augments with the name and position of its 'const' declaration.
-type NamedConst struct {
+type TyNamedConst struct {
 }
 
+type NamedConst = *TyNamedConst
+
 // A Global is a named Value holding the address of a package-level
 // variable.
 //
 // Pos() returns the position of the ast.ValueSpec.Names[*]
 // identifier.
-type Global struct {
+type TyGlobal struct {
 	impl llvm.Value
 }
+
+type Global = *TyGlobal
+
+// Function represents the parameters, results, and code of a function
+// or method.
+//
+// If Blocks is nil, this indicates an external function for which no
+// Go source code is available.  In this case, FreeVars, Locals, and
+// Params are nil too.  Clients performing whole-program analysis must
+// handle external functions specially.
+//
+// Blocks contains the function's control-flow graph (CFG).
+// Blocks[0] is the function entry point; block order is not otherwise
+// semantically significant, though it may affect the readability of
+// the disassembly.
+// To iterate over the blocks in dominance order, use DomPreorder().
+//
+// Recover is an optional second entry point to which control resumes
+// after a recovered panic.  The Recover block may contain only a return
+// statement, preceded by a load of the function's named return
+// parameters, if any.
+//
+// A nested function (Parent()!=nil) that refers to one or more
+// lexically enclosing local variables ("free variables") has FreeVars.
+// Such functions cannot be called directly but require a
+// value created by MakeClosure which, via its Bindings, supplies
+// values for these parameters.
+//
+// If the function is a method (Signature.Recv() != nil) then the first
+// element of Params is the receiver parameter.
+//
+// A Go package may declare many functions called "init".
+// For each one, Object().Name() returns "init" but Name() returns
+// "init#1", etc, in declaration order.
+//
+// Pos() returns the declaring ast.FuncLit.Type.Func or the position
+// of the ast.FuncDecl.Name, if the function was explicit in the
+// source.  Synthetic wrappers, for which Synthetic != "", may share
+// the same position as the function they wrap.
+// Syntax.Pos() always returns the position of the declaring "func" token.
+//
+// Type() returns the function's Signature.
+//
+// A generic function is a function or method that has uninstantiated type
+// parameters (TypeParams() != nil). Consider a hypothetical generic
+// method, (*Map[K,V]).Get. It may be instantiated with all ground
+// (non-parameterized) types as (*Map[string,int]).Get or with
+// parameterized types as (*Map[string,U]).Get, where U is a type parameter.
+// In both instantiations, Origin() refers to the instantiated generic
+// method, (*Map[K,V]).Get, TypeParams() refers to the parameters [K,V] of
+// the generic method. TypeArgs() refers to [string,U] or [string,int],
+// respectively, and is nil in the generic method.
+type TyFunction struct {
+	impl llvm.Value
+	prog Program
+}
+
+type Function = *TyFunction
+
+func (p *TyFunction) BodyStart() *BasicBlock {
+	body := llvm.AddBasicBlock(p.impl, "entry")
+	return &BasicBlock{body}
+}
diff --git a/ssa/expr.go b/ssa/expr.go
new file mode 100644
index 00000000..4c151a79
--- /dev/null
+++ b/ssa/expr.go
@@ -0,0 +1,17 @@
+/*
+ * 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
diff --git a/ssa/func.go b/ssa/func.go
deleted file mode 100644
index 3890bff7..00000000
--- a/ssa/func.go
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * 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 (
-	"github.com/goplus/llvm"
-)
-
-// Function represents the parameters, results, and code of a function
-// or method.
-//
-// If Blocks is nil, this indicates an external function for which no
-// Go source code is available.  In this case, FreeVars, Locals, and
-// Params are nil too.  Clients performing whole-program analysis must
-// handle external functions specially.
-//
-// Blocks contains the function's control-flow graph (CFG).
-// Blocks[0] is the function entry point; block order is not otherwise
-// semantically significant, though it may affect the readability of
-// the disassembly.
-// To iterate over the blocks in dominance order, use DomPreorder().
-//
-// Recover is an optional second entry point to which control resumes
-// after a recovered panic.  The Recover block may contain only a return
-// statement, preceded by a load of the function's named return
-// parameters, if any.
-//
-// A nested function (Parent()!=nil) that refers to one or more
-// lexically enclosing local variables ("free variables") has FreeVars.
-// Such functions cannot be called directly but require a
-// value created by MakeClosure which, via its Bindings, supplies
-// values for these parameters.
-//
-// If the function is a method (Signature.Recv() != nil) then the first
-// element of Params is the receiver parameter.
-//
-// A Go package may declare many functions called "init".
-// For each one, Object().Name() returns "init" but Name() returns
-// "init#1", etc, in declaration order.
-//
-// Pos() returns the declaring ast.FuncLit.Type.Func or the position
-// of the ast.FuncDecl.Name, if the function was explicit in the
-// source.  Synthetic wrappers, for which Synthetic != "", may share
-// the same position as the function they wrap.
-// Syntax.Pos() always returns the position of the declaring "func" token.
-//
-// Type() returns the function's Signature.
-//
-// A generic function is a function or method that has uninstantiated type
-// parameters (TypeParams() != nil). Consider a hypothetical generic
-// method, (*Map[K,V]).Get. It may be instantiated with all ground
-// (non-parameterized) types as (*Map[string,int]).Get or with
-// parameterized types as (*Map[string,U]).Get, where U is a type parameter.
-// In both instantiations, Origin() refers to the instantiated generic
-// method, (*Map[K,V]).Get, TypeParams() refers to the parameters [K,V] of
-// the generic method. TypeArgs() refers to [string,U] or [string,int],
-// respectively, and is nil in the generic method.
-type Function struct {
-	impl llvm.Value
-}
diff --git a/ssa/operator.go b/ssa/operator.go
new file mode 100644
index 00000000..31232763
--- /dev/null
+++ b/ssa/operator.go
@@ -0,0 +1,178 @@
+/*
+ * 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/token"
+
+	"github.com/goplus/llvm"
+)
+
+type valueKind = int
+
+type Value struct {
+	impl llvm.Value
+	kind valueKind
+}
+
+const (
+	mathOpBase = token.ADD
+	mathOpLast = token.REM
+)
+
+const (
+	vkInvalid valueKind = iota
+	vkSigned
+	vkUnsigned
+	vkFloat
+	vkComplex
+	vkString
+	vkBool
+)
+
+var mathOpToLLVM = []llvm.Opcode{
+	int(token.ADD-mathOpBase)<<2 | vkSigned:   llvm.Add,
+	int(token.ADD-mathOpBase)<<2 | vkUnsigned: llvm.Add,
+	int(token.ADD-mathOpBase)<<2 | vkFloat:    llvm.FAdd,
+
+	int(token.SUB-mathOpBase)<<2 | vkSigned:   llvm.Sub,
+	int(token.SUB-mathOpBase)<<2 | vkUnsigned: llvm.Sub,
+	int(token.SUB-mathOpBase)<<2 | vkFloat:    llvm.FSub,
+
+	int(token.MUL-mathOpBase)<<2 | vkSigned:   llvm.Mul,
+	int(token.MUL-mathOpBase)<<2 | vkUnsigned: llvm.Mul,
+	int(token.MUL-mathOpBase)<<2 | vkFloat:    llvm.FMul,
+
+	int(token.QUO-mathOpBase)<<2 | vkSigned:   llvm.SDiv,
+	int(token.QUO-mathOpBase)<<2 | vkUnsigned: llvm.UDiv,
+	int(token.QUO-mathOpBase)<<2 | vkFloat:    llvm.FDiv,
+
+	int(token.REM-mathOpBase)<<2 | vkSigned:   llvm.SRem,
+	int(token.REM-mathOpBase)<<2 | vkUnsigned: llvm.URem,
+	int(token.REM-mathOpBase)<<2 | vkFloat:    llvm.FRem,
+}
+
+func mathOpIdx(op token.Token, x valueKind) int {
+	return int(op-mathOpBase)<<2 | x
+}
+
+// ADD SUB MUL QUO REM          + - * / %
+func isMathOp(op token.Token) bool {
+	return op >= mathOpBase && op <= mathOpLast
+}
+
+const (
+	logicOpBase = token.AND
+	logicOpLast = token.AND_NOT
+)
+
+var logicOpToLLVM = []llvm.Opcode{
+	token.AND - logicOpBase: llvm.And,
+	token.OR - logicOpBase:  llvm.Or,
+	token.XOR - logicOpBase: llvm.Xor,
+	token.SHL - logicOpBase: llvm.Shl,
+	token.SHR - logicOpBase: llvm.LShr,
+}
+
+// AND OR XOR SHL SHR AND_NOT   & | ^ << >> &^
+func isLogicOp(op token.Token) bool {
+	return op >= logicOpBase && op <= logicOpLast
+}
+
+const (
+	predOpBase = token.EQL
+	predOpLast = token.GEQ
+)
+
+var intPredOpToLLVM = []llvm.IntPredicate{
+	token.EQL - predOpBase: llvm.IntEQ,
+	token.NEQ - predOpBase: llvm.IntNE,
+	token.LSS - predOpBase: llvm.IntSLT,
+	token.LEQ - predOpBase: llvm.IntSLE,
+	token.GTR - predOpBase: llvm.IntSGT,
+	token.GEQ - predOpBase: llvm.IntSGE,
+}
+
+var uintPredOpToLLVM = []llvm.IntPredicate{
+	token.EQL - predOpBase: llvm.IntEQ,
+	token.NEQ - predOpBase: llvm.IntNE,
+	token.LSS - predOpBase: llvm.IntULT,
+	token.LEQ - predOpBase: llvm.IntULE,
+	token.GTR - predOpBase: llvm.IntUGT,
+	token.GEQ - predOpBase: llvm.IntUGE,
+}
+
+var floatPredOpToLLVM = []llvm.FloatPredicate{
+	token.EQL - predOpBase: llvm.FloatOEQ,
+	token.NEQ - predOpBase: llvm.FloatONE,
+	token.LSS - predOpBase: llvm.FloatOLT,
+	token.LEQ - predOpBase: llvm.FloatOLE,
+	token.GTR - predOpBase: llvm.FloatOGT,
+	token.GEQ - predOpBase: llvm.FloatOGE,
+}
+
+// EQL NEQ LSS LEQ GTR GEQ      == != < <= < >=
+func isPredOp(op token.Token) bool {
+	return op >= predOpBase && op <= predOpLast
+}
+
+// op:
+// ADD SUB MUL QUO REM          + - * / %
+// AND OR XOR SHL SHR AND_NOT   & | ^ << >> &^
+// EQL NEQ LSS LEQ GTR GEQ      == != < <= < >=
+func (b Builder) BinOp(op token.Token, x, y Value) (v Value) {
+	switch {
+	case isMathOp(op): // op: + - * / %
+		switch x.kind {
+		case vkString, vkComplex:
+			panic("todo")
+		}
+		idx := mathOpIdx(op, x.kind)
+		if llop := mathOpToLLVM[idx]; llop != 0 {
+			v.impl = llvm.CreateBinOp(b.impl, llop, x.impl, y.impl)
+			return
+		}
+	case isLogicOp(op): // op: & | ^ << >> &^
+		if op == token.AND_NOT {
+			panic("todo")
+		}
+		llop := logicOpToLLVM[op-logicOpBase]
+		if op == token.SHR && x.kind == vkUnsigned {
+			llop = llvm.AShr
+		}
+		v.impl = llvm.CreateBinOp(b.impl, llop, x.impl, y.impl)
+		return
+	case isPredOp(op): // op: == != < <= < >=
+		switch x.kind {
+		case vkSigned:
+			pred := intPredOpToLLVM[op-predOpBase]
+			v.impl = llvm.CreateICmp(b.impl, pred, x.impl, y.impl)
+			return
+		case vkUnsigned:
+			pred := uintPredOpToLLVM[op-predOpBase]
+			v.impl = llvm.CreateICmp(b.impl, pred, x.impl, y.impl)
+			return
+		case vkFloat:
+			pred := floatPredOpToLLVM[op-predOpBase]
+			v.impl = llvm.ConstFCmp(pred, x.impl, y.impl)
+			return
+		case vkString, vkComplex, vkBool:
+			panic("todo")
+		}
+	}
+	return
+}
diff --git a/ssa/package.go b/ssa/package.go
index 1c897fc7..5bc7fe8c 100644
--- a/ssa/package.go
+++ b/ssa/package.go
@@ -25,8 +25,9 @@ import (
 )
 
 // A Program is a partial or complete Go program converted to SSA form.
-type Program struct {
+type TyProgram struct {
 	ctx  llvm.Context
+	b    Builder
 	typs typeutil.Map
 
 	target *Target
@@ -42,20 +43,28 @@ type Program struct {
 	voidPtrTy llvm.Type
 }
 
-func NewProgram(target *Target) *Program {
+type Program = *TyProgram
+
+func NewProgram(target *Target) Program {
 	if target == nil {
 		target = &Target{}
 	}
 	ctx := llvm.NewContext()
 	ctx.Finalize()
+	b := ctx.NewBuilder()
+	b.Finalize()
 	td := llvm.NewTargetData("") // TODO(xsw): target config
-	return &Program{ctx: ctx, target: target, td: td}
+	return &TyProgram{ctx: ctx, b: Builder{b}, target: target, td: td}
 }
 
-func (p *Program) NewPackage(name, pkgPath string) *Package {
+func (p *TyProgram) NewPackage(name, pkgPath string) Package {
 	mod := p.ctx.NewModule(pkgPath)
 	mod.Finalize()
-	return &Package{mod, p}
+	return &TyPackage{mod, p}
+}
+
+func (p *TyProgram) Builder() Builder {
+	return p.b
 }
 
 // A Package is a single analyzed Go package containing Members for
@@ -66,26 +75,28 @@ func (p *Program) NewPackage(name, pkgPath string) *Package {
 // Members also contains entries for "init" (the synthetic package
 // initializer) and "init#%d", the nth declared init function,
 // and unspecified other things too.
-type Package struct {
+type TyPackage struct {
 	mod  llvm.Module
-	prog *Program
+	prog Program
 }
 
-func (p *Package) NewConst(name string, val constant.Value) *NamedConst {
-	return &NamedConst{}
+type Package = *TyPackage
+
+func (p *TyPackage) NewConst(name string, val constant.Value) NamedConst {
+	return &TyNamedConst{}
 }
 
-func (p *Package) NewVar(name string, typ types.Type) *Global {
+func (p *TyPackage) NewVar(name string, typ types.Type) Global {
 	gbl := llvm.AddGlobal(p.mod, p.prog.llvmType(typ), name)
-	return &Global{gbl}
+	return &TyGlobal{gbl}
 }
 
-func (p *Package) NewFunc(name string, sig *types.Signature) *Function {
+func (p *TyPackage) NewFunc(name string, sig *types.Signature) Function {
 	fn := llvm.AddFunction(p.mod, name, p.prog.llvmSignature(sig))
-	return &Function{fn}
+	return &TyFunction{fn, p.prog}
 }
 
-func (p *Package) String() string {
+func (p *TyPackage) String() string {
 	return p.mod.String()
 }
 
diff --git a/ssa/ssa_test.go b/ssa/ssa_test.go
index eed37539..8bd2aabe 100644
--- a/ssa/ssa_test.go
+++ b/ssa/ssa_test.go
@@ -33,7 +33,7 @@ func asmPkg(t *testing.T, p *Package) {
 }
 */
 
-func assertPkg(t *testing.T, p *Package, expected string) {
+func assertPkg(t *testing.T, p Package, expected string) {
 	if v := p.String(); v != expected {
 		t.Fatalf("\n==> got:\n%s\n==> expected:\n%s\n", v, expected)
 	}
diff --git a/ssa/type.go b/ssa/type.go
index d4a87ea9..91a660f3 100644
--- a/ssa/type.go
+++ b/ssa/type.go
@@ -29,7 +29,7 @@ type Type struct {
 }
 */
 
-func (p *Program) llvmType(typ types.Type) llvm.Type {
+func (p *TyProgram) llvmType(typ types.Type) llvm.Type {
 	if v := p.typs.At(typ); v != nil {
 		return v.(llvm.Type)
 	}
@@ -38,7 +38,7 @@ func (p *Program) llvmType(typ types.Type) llvm.Type {
 	return ret
 }
 
-func (p *Program) llvmSignature(sig *types.Signature) llvm.Type {
+func (p *TyProgram) llvmSignature(sig *types.Signature) llvm.Type {
 	if v := p.typs.At(sig); v != nil {
 		return v.(llvm.Type)
 	}
@@ -47,56 +47,56 @@ func (p *Program) llvmSignature(sig *types.Signature) llvm.Type {
 	return ret
 }
 
-func (p *Program) tyVoidPtr() llvm.Type {
+func (p *TyProgram) tyVoidPtr() llvm.Type {
 	if p.voidPtrTy.IsNil() {
 		p.voidPtrTy = llvm.PointerType(p.tyVoid(), 0)
 	}
 	return p.voidPtrTy
 }
 
-func (p *Program) tyVoid() llvm.Type {
+func (p *TyProgram) tyVoid() llvm.Type {
 	if p.voidType.IsNil() {
 		p.voidType = p.ctx.VoidType()
 	}
 	return p.voidType
 }
 
-func (p *Program) tyInt() llvm.Type {
+func (p *TyProgram) tyInt() llvm.Type {
 	if p.intType.IsNil() {
 		p.intType = llvmIntType(p.ctx, p.td.PointerSize())
 	}
 	return p.intType
 }
 
-func (p *Program) tyInt8() llvm.Type {
+func (p *TyProgram) tyInt8() llvm.Type {
 	if p.int8Type.IsNil() {
 		p.int8Type = p.ctx.Int8Type()
 	}
 	return p.int8Type
 }
 
-func (p *Program) tyInt16() llvm.Type {
+func (p *TyProgram) tyInt16() llvm.Type {
 	if p.int16Type.IsNil() {
 		p.int16Type = p.ctx.Int16Type()
 	}
 	return p.int16Type
 }
 
-func (p *Program) tyInt32() llvm.Type {
+func (p *TyProgram) tyInt32() llvm.Type {
 	if p.int32Type.IsNil() {
 		p.int32Type = p.ctx.Int32Type()
 	}
 	return p.int32Type
 }
 
-func (p *Program) tyInt64() llvm.Type {
+func (p *TyProgram) tyInt64() llvm.Type {
 	if p.int64Type.IsNil() {
 		p.int64Type = p.ctx.Int64Type()
 	}
 	return p.int64Type
 }
 
-func (p *Program) toLLVMType(typ types.Type) llvm.Type {
+func (p *TyProgram) toLLVMType(typ types.Type) llvm.Type {
 	switch t := typ.(type) {
 	case *types.Basic:
 		switch t.Kind() {
@@ -146,19 +146,19 @@ func llvmIntType(ctx llvm.Context, size int) llvm.Type {
 	return ctx.Int64Type()
 }
 
-func (p *Program) toLLVMNamedStruct(name string, typ *types.Struct) llvm.Type {
+func (p *TyProgram) toLLVMNamedStruct(name string, typ *types.Struct) llvm.Type {
 	t := p.ctx.StructCreateNamed(name)
 	fields := p.toLLVMFields(typ)
 	t.StructSetBody(fields, false)
 	return t
 }
 
-func (p *Program) toLLVMStruct(typ *types.Struct) llvm.Type {
+func (p *TyProgram) toLLVMStruct(typ *types.Struct) llvm.Type {
 	fields := p.toLLVMFields(typ)
 	return p.ctx.StructType(fields, false)
 }
 
-func (p *Program) toLLVMFields(typ *types.Struct) []llvm.Type {
+func (p *TyProgram) toLLVMFields(typ *types.Struct) []llvm.Type {
 	n := typ.NumFields()
 	fields := make([]llvm.Type, n)
 	for i := 0; i < n; i++ {
@@ -167,11 +167,11 @@ func (p *Program) toLLVMFields(typ *types.Struct) []llvm.Type {
 	return fields
 }
 
-func (p *Program) toLLVMTuple(t *types.Tuple) llvm.Type {
+func (p *TyProgram) toLLVMTuple(t *types.Tuple) llvm.Type {
 	return p.ctx.StructType(p.toLLVMTypes(t), false)
 }
 
-func (p *Program) toLLVMTypes(t *types.Tuple) []llvm.Type {
+func (p *TyProgram) toLLVMTypes(t *types.Tuple) []llvm.Type {
 	n := t.Len()
 	ret := make([]llvm.Type, n)
 	for i := 0; i < n; i++ {
@@ -180,7 +180,7 @@ func (p *Program) toLLVMTypes(t *types.Tuple) []llvm.Type {
 	return ret
 }
 
-func (p *Program) toLLVMFunc(sig *types.Signature) llvm.Type {
+func (p *TyProgram) toLLVMFunc(sig *types.Signature) llvm.Type {
 	params := p.toLLVMTypes(sig.Params())
 	results := sig.Results()
 	var ret llvm.Type
@@ -195,7 +195,7 @@ func (p *Program) toLLVMFunc(sig *types.Signature) llvm.Type {
 	return llvm.FunctionType(ret, params, sig.Variadic())
 }
 
-func (p *Program) toLLVMNamed(typ *types.Named) llvm.Type {
+func (p *TyProgram) toLLVMNamed(typ *types.Named) llvm.Type {
 	name := typ.Obj().Name()
 	switch typ := typ.Underlying().(type) {
 	case *types.Struct: