polkawasm: add custom gc that relies on an external allocator

builder/build.go

@@ -816,15 +816,25 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 					args = append(args, "--asyncify")
 				}
 
-				args = append(args,
-					opt,
-					"-g",
-					result.Executable,
-					"--output", result.Executable,
-				)
-
 				if config.Target.Triple == "wasm32-unknown-polkawasm" {
-					args = append(args, "--signext-lowering")
+					args = append(args,
+						opt,
+						"--signext-lowering",
+						// "--signature-pruning",
+						// "--const-hoisting",
+						// "--mvp-features",
+						result.Executable,
+						"--output",
+						result.Executable,
+					)
+				} else {
+					args = append(args,
+						opt,
+						"-g",
+						result.Executable,
+						"--output",
+						result.Executable,
+					)
 				}
 
 				cmd := exec.Command(goenv.Get("WASMOPT"), args...)

compileopts/config.go

@@ -104,7 +104,7 @@ func (c *Config) GC() string {
 // that can be traced by the garbage collector.
 func (c *Config) NeedsStackObjects() bool {
 	switch c.GC() {
-	case "conservative", "custom", "precise":
+	case "conservative", "custom", "extalloc", "extalloc_leaking", "precise":
 		for _, tag := range c.BuildTags() {
 			if tag == "tinygo.wasm" {
 				return true
@@ -152,6 +152,8 @@ func (c *Config) OptLevel() (level string, speedLevel, sizeLevel int) {
 		return "O1", 1, 0
 	case "2":
 		return "O2", 2, 0
+	case "3":
+		return "O3", 2, 0
 	case "s":
 		return "Os", 2, 1
 	case "z":

compileopts/options.go

@@ -8,12 +8,12 @@ import (
 )
 
 var (
-	validGCOptions            = []string{"none", "leaking", "conservative", "custom", "precise"}
+	validGCOptions            = []string{"none", "leaking", "conservative", "custom", "extalloc", "extalloc_leaking", "precise"}
 	validSchedulerOptions     = []string{"none", "tasks", "asyncify"}
 	validSerialOptions        = []string{"none", "uart", "usb"}
 	validPrintSizeOptions     = []string{"none", "short", "full"}
 	validPanicStrategyOptions = []string{"print", "trap"}
-	validOptOptions           = []string{"none", "0", "1", "2", "s", "z"}
+	validOptOptions           = []string{"none", "0", "1", "2", "3", "s", "z"}
 )
 
 // Options contains extra options to give to the compiler. These options are

compileopts/options_test.go

@@ -9,7 +9,7 @@ import (
 
 func TestVerifyOptions(t *testing.T) {
 
-	expectedGCError := errors.New(`invalid gc option 'incorrect': valid values are none, leaking, conservative, custom, precise`)
+	expectedGCError := errors.New(`invalid gc option 'incorrect': valid values are none, leaking, conservative, custom, extalloc, extalloc_leaking, precise`)
 	expectedSchedulerError := errors.New(`invalid scheduler option 'incorrect': valid values are none, tasks, asyncify`)
 	expectedPrintSizeError := errors.New(`invalid size option 'incorrect': valid values are none, short, full`)
 	expectedPanicStrategyError := errors.New(`invalid panic option 'incorrect': valid values are print, trap`)

main.go

@@ -1406,7 +1406,7 @@ func main() {
 	}
 	command := os.Args[1]
 
-	opt := flag.String("opt", "z", "optimization level: 0, 1, 2, s, z")
+	opt := flag.String("opt", "z", "optimization level: 0, 1, 2, 3, s, z")
 	gc := flag.String("gc", "", "garbage collector to use (none, leaking, conservative)")
 	panicStrategy := flag.String("panic", "print", "panic strategy (print, trap)")
 	scheduler := flag.String("scheduler", "", "which scheduler to use (none, tasks, asyncify)")

src/runtime/arch_tinygowasm.go

@@ -66,7 +66,7 @@ var (
 func align(ptr uintptr) uintptr {
 	// Align to 16, which is the alignment of max_align_t:
 	// https://godbolt.org/z/dYqTsWrGq
-	const heapAlign = 16
+	const heapAlign = 8
 	return (ptr + heapAlign - 1) &^ (heapAlign - 1)
 }
 

src/runtime/gc_custom.go

@@ -1,5 +1,4 @@
 //go:build gc.custom
-// +build gc.custom
 
 package runtime
 

src/runtime/gc_debug.go

@@ -0,0 +1,47 @@
+//go:build gc.extalloc || gc.extalloc_leaking
+
+package runtime
+
+const gcDebug = false
+
+func printnum(num int) {
+	if num == 0 {
+		printstr("0")
+		return
+	}
+
+	digits := [16]int{} // store up to 16 digits
+	digitStrings := [10]string{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"}
+	count := 0 // count of digits
+
+	// extract digits from the number
+	for ; num > 0; num /= 10 {
+		digits[count] = num % 10
+		count++
+	}
+
+	// reverse the digits
+	for i := 0; i < count/2; i++ {
+		j := count - i - 1
+		digits[i], digits[j] = digits[j], digits[i]
+	}
+
+	// print each digit
+	for i := 0; i < count; i++ {
+		printstr(digitStrings[digits[i]])
+	}
+}
+
+func printstr(str string) {
+	if !gcDebug {
+		return
+	}
+
+	for i := 0; i < len(str); i++ {
+		if putcharPosition >= putcharBufferSize {
+			break
+		}
+
+		putchar(str[i])
+	}
+}