Use SSA parser from Go tools

Hopefully this makes the conversion a lot easier: now both sides of the
conversion are in SSA form.

tgo.go

@@ -5,12 +5,13 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"go/ast"
 	"go/constant"
 	"go/token"
 	"os"
 
 	"golang.org/x/tools/go/loader"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/ssautil"
 	"llvm.org/llvm/bindings/go/llvm"
 )
 
@@ -70,138 +71,164 @@ func (c *Compiler) Parse(path string) error {
 		// TODO: Build (build.Context) - GOOS, GOARCH, GOPATH, etc
 	}
 	config.CreateFromFilenames("main", path)
-	program, err := config.Load()
+	lprogram, err := config.Load()
 	if err != nil {
 		return err
 	}
 
-	pkgInfo := program.Created[0] // main?
-	if len(pkgInfo.Errors) != 0 {
-		return pkgInfo.Errors[0] // TODO: better error checking
-	}
-	fmt.Println("package:", pkgInfo.Pkg.Name())
-	for _, file := range pkgInfo.Files {
-		err := c.parseFile(pkgInfo.Pkg.Name(), file)
-		if err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
+	program := ssautil.CreateProgram(lprogram, ssa.SanityCheckFunctions)
+	program.Build()
+	for _, pkg := range program.AllPackages() {
+		fmt.Println("package:", pkg.Pkg.Name())
+		for name, member := range pkg.Members {
+			fmt.Println("member:", name, member, member.Token())
+			if member.Name() == "init" {
+				continue
+			}
+			switch member := member.(type) {
+			case *ssa.Function:
+				err := c.parseFunc(pkg.Pkg.Name(), member)
+				if err != nil {
+					return err
+				}
 
-func (c *Compiler) parseFile(pkgName string, file *ast.File) error {
-	for _, decl := range file.Decls {
-		switch v := decl.(type) {
-		case *ast.FuncDecl:
-			err := c.parseFunc(pkgName, v)
-			if err != nil {
-				return err
+			default:
+				fmt.Println("  TODO")
 			}
-		default:
-			return errors.New("unknown declaration")
 		}
 	}
 
 	return nil
 }
 
-func (c *Compiler) parseFunc(pkgName string, f *ast.FuncDecl) error {
-	fmt.Println("func:", f.Name)
+func (c *Compiler) parseFunc(pkgName string, f *ssa.Function) error {
+	fmt.Println("func:", f.Name(), f.Blocks, "len:", len(f.Blocks))
 
 	var fnType llvm.Type
-	if f.Type.Results == nil {
+	if f.Signature.Results() == nil {
 		fnType = llvm.FunctionType(llvm.VoidType(), nil, false)
 	} else {
 		return errors.New("todo: return values")
 	}
 
-	fn := llvm.AddFunction(c.mod, pkgName + "." + f.Name.Name, fnType)
+	fn := llvm.AddFunction(c.mod, pkgName + "." + f.Name(), fnType)
 	start := c.ctx.AddBasicBlock(fn, "start")
 	c.builder.SetInsertPointAtEnd(start)
 
 	// TODO: external functions
-	for _, stmt := range f.Body.List {
-		err := c.parseStmt(stmt)
-		if err != nil {
-			return err
+	for _, block := range f.Blocks {
+		for _, instr := range block.Instrs {
+			fmt.Printf("  instr: %v\n", instr)
+			err := c.parseInstr(instr)
+			if err != nil {
+				return err
+			}
 		}
 	}
-
-	if f.Type.Results == nil {
-		c.builder.CreateRetVoid()
-	//} else if len(f.Type.Results.List) == 1 {
-	//	c.builder.CreateRet(llvm.ConstInt(llvm.Int32Type(), 0, false))
-	}
 	return nil
 }
 
-func (c *Compiler) parseStmt(stmt ast.Node) error {
-	switch v := stmt.(type) {
-	case *ast.ExprStmt:
-		err := c.parseExpr(v.X)
-		if err != nil {
-			return err
+func (c *Compiler) parseInstr(instr ssa.Instruction) error {
+	switch instr := instr.(type) {
+	case *ssa.Call:
+		switch call := instr.Common().Value.(type) {
+		case *ssa.Builtin:
+			return c.parseBuiltin(instr.Common(), call)
+		default:
+			return errors.New("todo: unknown call type: " + fmt.Sprintf("%#v", call))
 		}
+	case *ssa.Return:
+		if len(instr.Results) == 0 {
+			c.builder.CreateRetVoid()
+			return nil
+		} else {
+			return errors.New("todo: return value")
+		}
+	case *ssa.BinOp:
+		return c.parseBinOp(instr)
 	default:
-		return errors.New("unknown stmt")
+		return errors.New("unknown instruction: " + fmt.Sprintf("%#v", instr))
 	}
-	return nil
 }
 
-func (c *Compiler) parseExpr(expr ast.Expr) error {
-	switch v := expr.(type) {
-	case *ast.CallExpr:
-		name := v.Fun.(*ast.Ident).Name
-		fmt.Printf("  call: %s\n", name)
-
-		printnl := false
-		if name == "println" {
-			printnl = true
-		} else if name == "print" {
-		} else {
-			return errors.New("todo: call anything other than println()")
-		}
+func (c *Compiler) parseBuiltin(instr *ssa.CallCommon, call *ssa.Builtin) error {
+	fmt.Printf("    builtin: %#v\n", call)
+	name := call.Name()
 
-		for i, arg := range v.Args {
+	switch name {
+	case "print", "println":
+		for i, arg := range instr.Args {
 			if i >= 1 {
 				c.builder.CreateCall(c.printspaceFunc, nil, "")
 			}
-			switch arg := arg.(type) {
-			case *ast.BasicLit:
-				fmt.Printf("    arg: %s\n", arg.Value)
-				val := constant.MakeFromLiteral(arg.Value, arg.Kind, 0)
-				switch arg.Kind {
-				case token.STRING:
-					str := constant.StringVal(val)
-					strVal := c.ctx.ConstString(str, false)
-					strLen := llvm.ConstInt(llvm.Int32Type(), uint64(len(str)), false)
-					strObj := llvm.ConstStruct([]llvm.Value{strLen, strVal}, false)
-					ptr := llvm.AddGlobal(c.mod, strObj.Type(), ".str")
-					ptr.SetInitializer(strObj)
-					ptr.SetLinkage(llvm.InternalLinkage)
-					ptrCast := llvm.ConstPointerCast(ptr, c.stringPtrType)
-					c.builder.CreateCall(c.printstringFunc, []llvm.Value{ptrCast}, "")
-				case token.INT:
-					n, _ := constant.Int64Val(val) // TODO: do something with the 'exact' return value?
-					val := llvm.ConstInt(llvm.Int32Type(), uint64(n), true)
-					c.builder.CreateCall(c.printintFunc, []llvm.Value{val}, "")
-				default:
-					return errors.New("todo: print anything other than strings")
-				}
+			fmt.Printf("    arg: %s\n", arg);
+			expr, err := c.parseExpr(arg)
+			if err != nil {
+				return err
+			}
+			switch expr.Type() {
+			case c.stringPtrType:
+				c.builder.CreateCall(c.printstringFunc, []llvm.Value{*expr}, "")
+			case llvm.Int32Type():
+				c.builder.CreateCall(c.printintFunc, []llvm.Value{*expr}, "")
 			default:
 				return errors.New("unknown arg type")
 			}
 		}
-		if printnl {
+		if name == "println" {
 			c.builder.CreateCall(c.printnlFunc, nil, "")
 		}
-	default:
-		return errors.New("unknown expr")
 	}
+
 	return nil
 }
 
+func (c *Compiler) parseBinOp(binop *ssa.BinOp) error {
+	x, err := c.parseExpr(binop.X)
+	if err != nil {
+		return err
+	}
+	y, err := c.parseExpr(binop.Y)
+	if err != nil {
+		return err
+	}
+	switch binop.Op {
+	case token.ADD:
+		c.builder.CreateBinOp(llvm.Add, *x, *y, "")
+		return nil
+	case token.MUL:
+		c.builder.CreateBinOp(llvm.Mul, *x, *y, "")
+		return nil
+	}
+	return errors.New("todo: unknown binop")
+}
+
+func (c *Compiler) parseExpr(expr ssa.Value) (*llvm.Value, error) {
+	fmt.Printf("      expr: %v\n", expr)
+	switch expr := expr.(type) {
+	case *ssa.Const:
+		switch expr.Value.Kind() {
+		case constant.String:
+			str := constant.StringVal(expr.Value)
+			strVal := c.ctx.ConstString(str, false)
+			strLen := llvm.ConstInt(llvm.Int32Type(), uint64(len(str)), false)
+			strObj := llvm.ConstStruct([]llvm.Value{strLen, strVal}, false)
+			ptr := llvm.AddGlobal(c.mod, strObj.Type(), ".str")
+			ptr.SetInitializer(strObj)
+			ptr.SetLinkage(llvm.InternalLinkage)
+			ptrCast := llvm.ConstPointerCast(ptr, c.stringPtrType)
+			return &ptrCast, nil
+		case constant.Int:
+			n, _ := constant.Int64Val(expr.Value) // TODO: do something with the 'exact' return value?
+			val := llvm.ConstInt(llvm.Int32Type(), uint64(n), true)
+			return &val, nil
+		default:
+			return nil, errors.New("todo: unknown constant")
+		}
+	}
+	return nil, errors.New("todo: unknown expression: " + fmt.Sprintf("%#v", expr))
+}
+
 // IR returns the whole IR as a human-readable string.
 func (c *Compiler) IR() string {
 	return c.mod.String()