main: run the compiler from any path

compiler/compiler.go

@@ -134,7 +134,7 @@ func (c *Compiler) Module() llvm.Module {
 	return c.mod
 }
 
-func (c *Compiler) Parse(mainPath string, buildTags []string) error {
+func (c *Compiler) Parse(mainPath, sourceDir string, buildTags []string) error {
 	tripleSplit := strings.Split(c.triple, "-")
 
 	config := loader.Config{
@@ -148,7 +148,7 @@ func (c *Compiler) Parse(mainPath string, buildTags []string) error {
 		Build: &build.Context{
 			GOARCH:      tripleSplit[0],
 			GOOS:        tripleSplit[2],
-			GOROOT:      ".",
+			GOROOT:      sourceDir,
 			GOPATH:      runtime.GOROOT(),
 			CgoEnabled:  true,
 			UseAllFiles: false,

main.go

@@ -32,7 +32,7 @@ func Compile(pkgName, outpath string, spec *TargetSpec, printIR, dumpSSA bool, p
 				fmt.Println(c.IR())
 			}()
 		}
-		return c.Parse(pkgName, spec.BuildTags)
+		return c.Parse(pkgName, sourceDir(), spec.BuildTags)
 	}()
 	if parseErr != nil {
 		return parseErr
@@ -93,6 +93,7 @@ func Compile(pkgName, outpath string, spec *TargetSpec, printIR, dumpSSA bool, p
 		cmd := exec.Command(spec.Linker, args...)
 		cmd.Stdout = os.Stdout
 		cmd.Stderr = os.Stderr
+		cmd.Dir = sourceDir()
 		err = cmd.Run()
 		if err != nil {
 			return err
@@ -182,6 +183,7 @@ func Flash(pkgName, target, port string, printIR, dumpSSA bool, printSizes strin
 		cmd := exec.Command("/bin/sh", "-c", flashCmd)
 		cmd.Stdout = os.Stdout
 		cmd.Stderr = os.Stderr
+		cmd.Dir = sourceDir()
 		return cmd.Run()
 	})
 }
@@ -192,7 +194,7 @@ func Run(pkgName string) error {
 	if err != nil {
 		return errors.New("compiler: " + err.Error())
 	}
-	err = c.Parse(pkgName, []string{runtime.GOOS, runtime.GOARCH})
+	err = c.Parse(pkgName, sourceDir(), []string{runtime.GOOS, runtime.GOARCH})
 	if err != nil {
 		return errors.New("compiler: " + err.Error())
 	}

target.go

@@ -34,7 +34,7 @@ func LoadTarget(target string) (*TargetSpec, error) {
 
 	// See whether there is a target specification for this target (e.g.
 	// Arduino).
-	path := filepath.Join("targets", strings.ToLower(target)+".json")
+	path := filepath.Join(sourceDir(), "targets", strings.ToLower(target)+".json")
 	if fp, err := os.Open(path); err == nil {
 		defer fp.Close()
 		err := json.NewDecoder(fp).Decode(spec)
@@ -50,3 +50,11 @@ func LoadTarget(target string) (*TargetSpec, error) {
 
 	return spec, nil
 }
+
+// Return the source directory of this package, or "." when it cannot be
+// recovered.
+func sourceDir() string {
+	// https://stackoverflow.com/a/32163888/559350
+	_, path, _, _ := runtime.Caller(0)
+	return filepath.Dir(path)
+}