Switch to go/loader

This does typechecking internally and makes importing packages a whole
lot easier in the future.

tgo.go

@@ -7,10 +7,10 @@ import (
 	"fmt"
 	"go/ast"
 	"go/constant"
-	"go/parser"
 	"go/token"
 	"os"
 
+	"golang.org/x/tools/go/loader"
 	"llvm.org/llvm/bindings/go/llvm"
 )
 
@@ -46,23 +46,41 @@ func NewCompiler(path, triplet string) (*Compiler, error) {
 	putsType := llvm.FunctionType(llvm.Int32Type(), []llvm.Type{llvm.PointerType(llvm.Int8Type(), 0)}, false)
 	c.putsFunc = llvm.AddFunction(c.mod, "puts", putsType)
 
-	mainType := llvm.FunctionType(llvm.Int32Type(), nil, false)
-	mainFunc := llvm.AddFunction(c.mod, "main", mainType)
-	start := c.ctx.AddBasicBlock(mainFunc, "start")
-	c.builder.SetInsertPointAtEnd(start)
-
 	return c, nil
 }
 
 func (c *Compiler) Parse(path string) error {
-	fset := token.NewFileSet()
-	file, err := parser.ParseFile(fset, path, nil, 0)
+	config := loader.Config {
+		// TODO: TypeChecker.Sizes
+		// TODO: Build (build.Context) - GOOS, GOARCH, GOPATH, etc
+	}
+	config.CreateFromFilenames("main", path)
+	program, err := config.Load()
 	if err != nil {
 		return err
 	}
 
-	fmt.Println("package:", file.Name.Name)
+	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(file)
+		if err != nil {
+			return err
+		}
+	}
 
+	return nil
+}
+
+func (c *Compiler) IR() string {
+	return c.mod.String()
+}
+
+
+func (c *Compiler) parseFile(file *ast.File) error {
 	for _, decl := range file.Decls {
 		switch v := decl.(type) {
 		case *ast.FuncDecl:
@@ -75,17 +93,17 @@ func (c *Compiler) Parse(path string) error {
 		}
 	}
 
-	c.builder.CreateRet(llvm.ConstInt(llvm.Int32Type(), 0, false))
-
 	return nil
 }
 
-func (c *Compiler) IR() string {
-	return c.mod.String()
-}
-
 func (c *Compiler) parseFunc(f *ast.FuncDecl) error {
 	fmt.Println("func:", f.Name)
+
+	fnType := llvm.FunctionType(llvm.Int32Type(), nil, false)
+	fn := llvm.AddFunction(c.mod, f.Name.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)
@@ -93,6 +111,8 @@ func (c *Compiler) parseFunc(f *ast.FuncDecl) error {
 			return err
 		}
 	}
+
+	c.builder.CreateRet(llvm.ConstInt(llvm.Int32Type(), 0, false))
 	return nil
 }