target/wasm_unknown: remove bulk memory and use imported memory for extreme tinyness

Signed-off-by: deadprogram <ron@hybridgroup.com>

Author: deadprogram

src/runtime/arch_tinygowasm_malloc.go

@@ -1,4 +1,4 @@
-//go:build tinygo.wasm && !custommalloc
+//go:build tinygo.wasm && !(custommalloc || wasm_unknown)
 
 package runtime
 

src/runtime/runtime_tinygowasm_unknown.go

@@ -31,10 +31,9 @@ func abort() {
 
 //go:linkname syscall_Exit syscall.Exit
 func syscall_Exit(code int) {
-	//proc_exit(uint32(code))
 }
 
-// TinyGo does not yet support any form of parallelism on WebAssembly, so these
+// There is not yet any support for any form of parallelism on WebAssembly, so these
 // can be left empty.
 
 //go:linkname procPin sync/atomic.runtime_procPin

src/runtime/runtime_wasm_unknown.go

@@ -2,9 +2,7 @@
 
 package runtime
 
-import (
-	"unsafe"
-)
+import "unsafe"
 
 type timeUnit int64
 
@@ -21,10 +19,6 @@ func _start() {
 	run()
 }
 
-// Read the command line arguments from WASI.
-// For example, they can be passed to a program with wasmtime like this:
-//
-//	wasmtime run ./program.wasm arg1 arg2
 func init() {
 	__wasm_call_ctors()
 }
@@ -39,7 +33,8 @@ func nanosecondsToTicks(ns int64) timeUnit {
 	return timeUnit(ns)
 }
 
-const timePrecisionNanoseconds = 1000 // TODO: how can we determine the appropriate `precision`?
+// with the wasm32-unknown-unknown target there is no way to determine any `precision`
+const timePrecisionNanoseconds = 1000
 
 func sleepTicks(d timeUnit) {
 }

targets/wasm-unknown.json

@@ -1,7 +1,7 @@
 {
 	"llvm-target":   "wasm32-unknown-unknown",
 	"cpu":           "generic",
-	"features":      "+bulk-memory,+mutable-globals,+nontrapping-fptoint,+sign-ext",
+	"features":      "+mutable-globals,+nontrapping-fptoint,+sign-ext",
 	"build-tags":    ["tinygo.wasm", "wasm_unknown"],
 	"goos":          "linux",
 	"goarch":        "arm",
@@ -10,13 +10,14 @@
 	"scheduler":     "none",
 	"default-stack-size": 4096,
 	"cflags": [
-		"-mbulk-memory",
+		"-mno-bulk-memory",
 		"-mnontrapping-fptoint",
 		"-msign-ext"
 	],
 	"ldflags": [
 		"--no-demangle",
-		"--no-entry"
+		"--no-entry",
+		"--import-memory"
 	],
 	"extra-files": [
 		"src/runtime/asm_tinygowasm.S"