diff --git a/compiler/compiler.go b/compiler/compiler.go
index 77300291..86d51a9e 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -28,10 +28,17 @@ func init() {
 	llvm.InitializeAllAsmPrinters()
 }
 
+// Configure the compiler.
+type Config struct {
+	Triple    string   // LLVM target triple, e.g. x86_64-unknown-linux-gnu (empty string means default)
+	DumpSSA   bool     // dump Go SSA, for compiler debugging
+	Debug     bool     // add debug symbols for gdb
+	RootDir   string   // GOROOT for TinyGo
+	BuildTags []string // build tags for TinyGo (empty means {runtime.GOOS/runtime.GOARCH})
+}
+
 type Compiler struct {
-	dumpSSA         bool
-	debug           bool
-	triple          string
+	Config
 	mod             llvm.Module
 	ctx             llvm.Context
 	builder         llvm.Builder
@@ -75,24 +82,28 @@ type Phi struct {
 	llvm llvm.Value
 }
 
-func NewCompiler(pkgName, triple string, dumpSSA bool) (*Compiler, error) {
+func NewCompiler(pkgName string, config Config) (*Compiler, error) {
+	if config.Triple == "" {
+		config.Triple = llvm.DefaultTargetTriple()
+	}
+	if len(config.BuildTags) == 0 {
+		config.BuildTags = []string{runtime.GOOS, runtime.GOARCH}
+	}
 	c := &Compiler{
-		dumpSSA: dumpSSA,
-		debug:   true, // TODO: make configurable
-		triple:  triple,
+		Config:  config,
 		difiles: make(map[string]llvm.Metadata),
 		ditypes: make(map[string]llvm.Metadata),
 	}
 
-	target, err := llvm.GetTargetFromTriple(triple)
+	target, err := llvm.GetTargetFromTriple(config.Triple)
 	if err != nil {
 		return nil, err
 	}
-	c.machine = target.CreateTargetMachine(triple, "", "", llvm.CodeGenLevelDefault, llvm.RelocStatic, llvm.CodeModelDefault)
+	c.machine = target.CreateTargetMachine(config.Triple, "", "", llvm.CodeGenLevelDefault, llvm.RelocStatic, llvm.CodeModelDefault)
 	c.targetData = c.machine.CreateTargetData()
 
 	c.mod = llvm.NewModule(pkgName)
-	c.mod.SetTarget(triple)
+	c.mod.SetTarget(config.Triple)
 	c.mod.SetDataLayout(c.targetData.String())
 	c.ctx = c.mod.Context()
 	c.builder = c.ctx.NewBuilder()
@@ -134,8 +145,8 @@ func (c *Compiler) Module() llvm.Module {
 	return c.mod
 }
 
-func (c *Compiler) Parse(mainPath, sourceDir string, buildTags []string) error {
-	tripleSplit := strings.Split(c.triple, "-")
+func (c *Compiler) Parse(mainPath string) error {
+	tripleSplit := strings.Split(c.Triple, "-")
 
 	config := loader.Config{
 		TypeChecker: types.Config{
@@ -148,12 +159,12 @@ func (c *Compiler) Parse(mainPath, sourceDir string, buildTags []string) error {
 		Build: &build.Context{
 			GOARCH:      tripleSplit[0],
 			GOOS:        tripleSplit[2],
-			GOROOT:      sourceDir,
+			GOROOT:      c.RootDir,
 			GOPATH:      runtime.GOROOT(),
 			CgoEnabled:  true,
 			UseAllFiles: false,
 			Compiler:    "gc", // must be one of the recognized compilers
-			BuildTags:   append([]string{"tgo"}, buildTags...),
+			BuildTags:   append([]string{"tgo"}, c.BuildTags...),
 		},
 		ParserMode:  parser.ParseComments,
 		AllowErrors: true,
@@ -303,7 +314,7 @@ func (c *Compiler) Parse(mainPath, sourceDir string, buildTags []string) error {
 			// continues at runtime).
 			// This should only happen when it hits a function call or the end
 			// of the block, ideally.
-			err := c.ir.Interpret(frame.fn.Blocks[0], c.dumpSSA)
+			err := c.ir.Interpret(frame.fn.Blocks[0], c.DumpSSA)
 			if err != nil {
 				return err
 			}
@@ -835,7 +846,7 @@ func (c *Compiler) parseFuncDecl(f *ir.Function) (*Frame, error) {
 		frame.fn.LLVMFn = llvm.AddFunction(c.mod, name, fnType)
 	}
 
-	if c.debug && f.Syntax() != nil && len(f.Blocks) != 0 {
+	if c.Debug && f.Syntax() != nil && len(f.Blocks) != 0 {
 		// Create debug info file if needed.
 		pos := c.ir.Program.Fset.Position(f.Syntax().Pos())
 		if _, ok := c.difiles[pos.Filename]; !ok {
@@ -1165,14 +1176,14 @@ func (c *Compiler) getInterpretedValue(prefix string, value ir.Value) (llvm.Valu
 }
 
 func (c *Compiler) parseFunc(frame *Frame) error {
-	if c.dumpSSA {
+	if c.DumpSSA {
 		fmt.Printf("\nfunc %s:\n", frame.fn.Function)
 	}
 	if !frame.fn.IsExported() {
 		frame.fn.LLVMFn.SetLinkage(llvm.InternalLinkage)
 	}
 
-	if c.debug {
+	if c.Debug {
 		pos := c.ir.Program.Fset.Position(frame.fn.Pos())
 		c.builder.SetCurrentDebugLocation(uint(pos.Line), uint(pos.Column), frame.difunc, llvm.Metadata{})
 	}
@@ -1204,7 +1215,7 @@ func (c *Compiler) parseFunc(frame *Frame) error {
 		frame.locals[param] = c.collapseFormalParam(llvmType, fields)
 
 		// Add debug information to this parameter (if available)
-		if c.debug && frame.fn.Syntax() != nil {
+		if c.Debug && frame.fn.Syntax() != nil {
 			pos := c.ir.Program.Fset.Position(frame.fn.Syntax().Pos())
 			dityp, err := c.getDIType(param.Type())
 			if err != nil {
@@ -1311,7 +1322,7 @@ func (c *Compiler) parseFunc(frame *Frame) error {
 
 	// Fill blocks with instructions.
 	for _, block := range frame.fn.DomPreorder() {
-		if c.dumpSSA {
+		if c.DumpSSA {
 			fmt.Printf("%s:\n", block.Comment)
 		}
 		c.builder.SetInsertPointAtEnd(frame.blocks[block])
@@ -1320,7 +1331,7 @@ func (c *Compiler) parseFunc(frame *Frame) error {
 			if _, ok := instr.(*ssa.DebugRef); ok {
 				continue
 			}
-			if c.dumpSSA {
+			if c.DumpSSA {
 				if val, ok := instr.(ssa.Value); ok && val.Name() != "" {
 					fmt.Printf("\t%s = %s\n", val.Name(), val.String())
 				} else {
@@ -1354,7 +1365,7 @@ func (c *Compiler) parseFunc(frame *Frame) error {
 }
 
 func (c *Compiler) parseInstr(frame *Frame, instr ssa.Instruction) error {
-	if c.debug {
+	if c.Debug {
 		pos := c.ir.Program.Fset.Position(instr.Pos())
 		c.builder.SetCurrentDebugLocation(uint(pos.Line), uint(pos.Column), frame.difunc, llvm.Metadata{})
 	}
diff --git a/main.go b/main.go
index 635b4e57..2965bb08 100644
--- a/main.go
+++ b/main.go
@@ -9,7 +9,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"runtime"
 	"strings"
 
 	"github.com/aykevl/llvm/bindings/go/llvm"
@@ -18,7 +17,14 @@ import (
 
 // Helper function for Compiler object.
 func Compile(pkgName, outpath string, spec *TargetSpec, printIR, dumpSSA bool, printSizes string, action func(string) error) error {
-	c, err := compiler.NewCompiler(pkgName, spec.Triple, dumpSSA)
+	config := compiler.Config{
+		Triple:    spec.Triple,
+		Debug:     true, // TODO: make configurable
+		DumpSSA:   dumpSSA,
+		RootDir:   sourceDir(),
+		BuildTags: spec.BuildTags,
+	}
+	c, err := compiler.NewCompiler(pkgName, config)
 	if err != nil {
 		return err
 	}
@@ -32,7 +38,7 @@ func Compile(pkgName, outpath string, spec *TargetSpec, printIR, dumpSSA bool, p
 				fmt.Println(c.IR())
 			}()
 		}
-		return c.Parse(pkgName, sourceDir(), spec.BuildTags)
+		return c.Parse(pkgName)
 	}()
 	if parseErr != nil {
 		return parseErr
@@ -190,11 +196,14 @@ func Flash(pkgName, target, port string, printIR, dumpSSA bool, printSizes strin
 
 // Run the specified package directly (using JIT or interpretation).
 func Run(pkgName string) error {
-	c, err := compiler.NewCompiler(pkgName, llvm.DefaultTargetTriple(), false)
+	config := compiler.Config{
+		RootDir: sourceDir(),
+	}
+	c, err := compiler.NewCompiler(pkgName, config)
 	if err != nil {
 		return errors.New("compiler: " + err.Error())
 	}
-	err = c.Parse(pkgName, sourceDir(), []string{runtime.GOOS, runtime.GOARCH})
+	err = c.Parse(pkgName)
 	if err != nil {
 		return errors.New("compiler: " + err.Error())
 	}