tinygo: add a flag for creating cpu profiles

main.go

@@ -15,6 +15,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"runtime"
+	"runtime/pprof"
 	"strconv"
 	"strings"
 	"sync/atomic"
@@ -1089,6 +1090,7 @@ func main() {
 	ldflags := flag.String("ldflags", "", "Go link tool compatible ldflags")
 	wasmAbi := flag.String("wasm-abi", "", "WebAssembly ABI conventions: js (no i64 params) or generic")
 	llvmFeatures := flag.String("llvm-features", "", "comma separated LLVM features to enable")
+	cpuprofile := flag.String("cpuprofile", "", "cpuprofile output")
 
 	var flagJSON, flagDeps, flagTest *bool
 	if command == "help" || command == "list" {
@@ -1173,6 +1175,20 @@ func main() {
 		os.Exit(1)
 	}
 
+	if *cpuprofile != "" {
+		f, err := os.Create(*cpuprofile)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "could not create CPU profile: ", err)
+			os.Exit(1)
+		}
+		defer f.Close()
+		if err := pprof.StartCPUProfile(f); err != nil {
+			fmt.Fprintln(os.Stderr, "could not start CPU profile: ", err)
+			os.Exit(1)
+		}
+		defer pprof.StopCPUProfile()
+	}
+
 	switch command {
 	case "build":
 		if outpath == "" {