main: add -programmer flag

This flag is overloaded. It can be used in two ways:

  * Choosing the flash method to use (openocd, msd, command).
  * Choosing the OpenOCD programmer name.

For example, you can use one of these to use OpenOCD instead of the
mass-storage device programmer:

    tinygo flash -target=microbit -programmer=openocd
    tinygo flash -target=microbit -programmer=cmsis-dap

compileopts/config.go

@@ -3,7 +3,9 @@
 package compileopts
 
 import (
+	"errors"
 	"fmt"
+	"regexp"
 	"strconv"
 	"strings"
 
@@ -152,6 +154,52 @@ func (c *Config) Debug() bool {
 	return c.Options.Debug
 }
 
+// Programmer returns the flash method and OpenOCD interface name given a
+// particular configuration. It may either be all configured in the target JSON
+// file or be modified using the -programmmer command-line option.
+func (c *Config) Programmer() (method, openocdInterface string) {
+	switch c.Options.Programmer {
+	case "":
+		// No configuration supplied.
+		return c.Target.FlashMethod, c.Target.OpenOCDInterface
+	case "openocd", "msd", "command":
+		// The -programmer flag only specifies the flash method.
+		return c.Options.Programmer, c.Target.OpenOCDInterface
+	default:
+		// The -programmer flag specifies something else, assume it specifies
+		// the OpenOCD interface name.
+		return "openocd", c.Options.Programmer
+	}
+}
+
+// OpenOCDConfiguration returns a list of command line arguments to OpenOCD.
+// This list of command-line arguments is based on the various OpenOCD-related
+// flags in the target specification.
+func (c *Config) OpenOCDConfiguration() (args []string, err error) {
+	_, openocdInterface := c.Programmer()
+	if openocdInterface == "" {
+		return nil, errors.New("OpenOCD programmer not set")
+	}
+	if !regexp.MustCompile("^[\\p{L}0-9_-]+$").MatchString(openocdInterface) {
+		return nil, fmt.Errorf("OpenOCD programmer has an invalid name: %#v", openocdInterface)
+	}
+	if c.Target.OpenOCDTarget == "" {
+		return nil, errors.New("OpenOCD chip not set")
+	}
+	if !regexp.MustCompile("^[\\p{L}0-9_-]+$").MatchString(c.Target.OpenOCDTarget) {
+		return nil, fmt.Errorf("OpenOCD target has an invalid name: %#v", c.Target.OpenOCDTarget)
+	}
+	if c.Target.OpenOCDTransport != "" && c.Target.OpenOCDTransport != "swd" {
+		return nil, fmt.Errorf("unknown OpenOCD transport: %#v", c.Target.OpenOCDTransport)
+	}
+	args = []string{"-f", "interface/" + openocdInterface + ".cfg"}
+	if c.Target.OpenOCDTransport != "" {
+		args = append(args, "-c", "transport select "+c.Target.OpenOCDTransport)
+	}
+	args = append(args, "-f", "target/"+c.Target.OpenOCDTarget+".cfg")
+	return args, nil
+}
+
 type TestConfig struct {
 	CompileTestBinary bool
 	// TODO: Filter the test functions to run, include verbose flag, etc

compileopts/options.go

@@ -19,4 +19,5 @@ type Options struct {
 	WasmAbi       string
 	HeapSize      int64
 	TestConfig    TestConfig
+	Programmer    string
 }

compileopts/target.go

@@ -5,11 +5,9 @@ package compileopts
 import (
 	"encoding/json"
 	"errors"
-	"fmt"
 	"io"
 	"os"
 	"path/filepath"
-	"regexp"
 	"runtime"
 	"strings"
 
@@ -277,30 +275,3 @@ func defaultTarget(goos, goarch, triple string) (*TargetSpec, error) {
 	}
 	return &spec, nil
 }
-
-// OpenOCDConfiguration returns a list of command line arguments to OpenOCD.
-// This list of command-line arguments is based on the various OpenOCD-related
-// flags in the target specification.
-func (spec *TargetSpec) OpenOCDConfiguration() (args []string, err error) {
-	if spec.OpenOCDInterface == "" {
-		return nil, errors.New("OpenOCD programmer not set")
-	}
-	if !regexp.MustCompile("^[\\p{L}0-9_-]+$").MatchString(spec.OpenOCDInterface) {
-		return nil, fmt.Errorf("OpenOCD programmer has an invalid name: %#v", spec.OpenOCDInterface)
-	}
-	if spec.OpenOCDTarget == "" {
-		return nil, errors.New("OpenOCD chip not set")
-	}
-	if !regexp.MustCompile("^[\\p{L}0-9_-]+$").MatchString(spec.OpenOCDTarget) {
-		return nil, fmt.Errorf("OpenOCD target has an invalid name: %#v", spec.OpenOCDTarget)
-	}
-	if spec.OpenOCDTransport != "" && spec.OpenOCDTransport != "swd" {
-		return nil, fmt.Errorf("unknown OpenOCD transport: %#v", spec.OpenOCDTransport)
-	}
-	args = []string{"-f", "interface/" + spec.OpenOCDInterface + ".cfg"}
-	if spec.OpenOCDTransport != "" {
-		args = append(args, "-c", "transport select "+spec.OpenOCDTransport)
-	}
-	args = append(args, "-f", "target/"+spec.OpenOCDTarget+".cfg")
-	return args, nil
-}