wasm: use wasip1 API for parameter/env passing

Instead of hardcoding the command line parameters and the environment
variables in the binary, pass them at runtime to Node.js and use the
WASIp1 API to retrieve them in wasm_exec.js.

The only real benefit right now is that it becomes possible to change
`go.argv` and `go.env` before running a wasm binary.

This also changes the syscall package for GOOS=js: it now becomes more
like a libc (using wasi-libc), which means error values like
`syscall.EEXIST` will actually match the one returned by the relevant
libc function.

Wasm binary size for packages that import the os package will be
increased somewhat.

.github/workflows/build-macos.yml

@@ -27,7 +27,6 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Install Dependencies
-        shell: bash
         run: |
           HOMEBREW_NO_AUTO_UPDATE=1 brew install qemu binaryen
       - name: Checkout
@@ -72,7 +71,6 @@ jobs:
           path: llvm-build
       - name: Build LLVM
         if: steps.cache-llvm-build.outputs.cache-hit != 'true'
-        shell: bash
         run: |
           # fetch LLVM source
           rm -rf llvm-project
@@ -100,14 +98,12 @@ jobs:
       - name: make gen-device
         run: make -j3 gen-device
       - name: Test TinyGo
-        shell: bash
         run: make test GOTESTFLAGS="-short"
       - name: Build TinyGo release tarball
         run: make release -j3
       - name: Test stdlib packages
         run: make tinygo-test
       - name: Make release artifact
-        shell: bash
         run: cp -p build/release.tar.gz build/tinygo.darwin-${{ matrix.goarch }}.tar.gz
       - name: Publish release artifact
         # Note: this release artifact is double-zipped, see:
@@ -121,7 +117,6 @@ jobs:
           name: darwin-${{ matrix.goarch }}-double-zipped
           path: build/tinygo.darwin-${{ matrix.goarch }}.tar.gz
       - name: Smoke tests
-        shell: bash
         run: make smoketest TINYGO=$(PWD)/build/tinygo
   test-macos-homebrew:
     name: homebrew-install

compileopts/target.go

@@ -452,7 +452,7 @@ func defaultTarget(options *Options) (*TargetSpec, error) {
 			"--stack-first",
 			"--no-demangle",
 		)
-		spec.Emulator = "wasmtime --dir={tmpDir}::/tmp {}"
+		spec.Emulator = "wasmtime run --dir={tmpDir}::/tmp {}"
 		spec.ExtraFiles = append(spec.ExtraFiles,
 			"src/runtime/asm_tinygowasm.S",
 			"src/internal/task/task_asyncify_wasm.S",

main.go

@@ -769,22 +769,18 @@ func Run(pkgName string, options *compileopts.Options, cmdArgs []string) error {
 // passes command line arguments and environment variables in a way appropriate
 // for the given emulator.
 func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, cmdArgs, environmentVars []string, timeout time.Duration, run func(cmd *exec.Cmd, result builder.BuildResult) error) (builder.BuildResult, error) {
-
-	isSingleFile := strings.HasSuffix(pkgName, ".go")
-
 	// Determine whether we're on a system that supports environment variables
-	// and command line parameters (operating systems, WASI) or not (baremetal,
-	// WebAssembly in the browser). If we're on a system without an environment,
-	// we need to pass command line arguments and environment variables through
-	// global variables (built into the binary directly) instead of the
-	// conventional way.
-	needsEnvInVars := config.GOOS() == "js"
+	// and command line parameters (operating systems, WASI) or not (baremetal).
+	// If we're on a system without an environment, we need to pass command line
+	// arguments and environment variables through global variables (built into
+	// the binary directly) instead of the conventional way.
+	needsEnvInVars := false
 	for _, tag := range config.BuildTags() {
 		if tag == "baremetal" {
 			needsEnvInVars = true
 		}
 	}
-	var args, emuArgs, env []string
+	var args, env []string
 	var extraCmdEnv []string
 	if needsEnvInVars {
 		runtimeGlobals := make(map[string]string)
@@ -804,20 +800,6 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 				"runtime": runtimeGlobals,
 			}
 		}
-	} else if config.EmulatorName() == "wasmtime" {
-		for _, v := range environmentVars {
-			emuArgs = append(emuArgs, "--env", v)
-		}
-
-		// Use of '--' argument no longer necessary as of Wasmtime v14:
-		// https://github.com/bytecodealliance/wasmtime/pull/6946
-		// args = append(args, "--")
-		args = append(args, cmdArgs...)
-
-		// Set this for nicer backtraces during tests, but don't override the user.
-		if _, ok := os.LookupEnv("WASMTIME_BACKTRACE_DETAILS"); !ok {
-			extraCmdEnv = append(extraCmdEnv, "WASMTIME_BACKTRACE_DETAILS=1")
-		}
 	} else {
 		// Pass environment variables and command line parameters as usual.
 		// This also works on qemu-aarch64 etc.
@@ -860,7 +842,7 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 			return result, err
 		}
 
-		name = emulator[0]
+		name, emulator = emulator[0], emulator[1:]
 
 		// wasmtime is a WebAssembly runtime CLI with WASI enabled by default.
 		// By default, only stdio is allowed. For example, while STDOUT routes
@@ -869,11 +851,24 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 		// outside the package directory. Other tests require temporary
 		// writeable directories. We allow this by adding wasmtime flags below.
 		if name == "wasmtime" {
+			var emuArgs []string
+
+			// Extract the wasmtime subcommand (e.g. "run" or "serve")
+			if len(emulator) > 1 {
+				emuArgs = append(emuArgs, emulator[0])
+				emulator = emulator[1:]
+			}
+
+			wd, _ := os.Getwd()
+
 			// Below adds additional wasmtime flags in case a test reads files
 			// outside its directory, like "../testdata/e.txt". This allows any
 			// relative directory up to the module root, even if the test never
 			// reads any files.
 			if config.TestConfig.CompileTestBinary {
+				// Set working directory to package dir
+				wd = result.MainDir
+
 				// Add relative dirs (../, ../..) up to module root (for wasip1)
 				dirs := dirsToModuleRootRel(result.MainDir, result.ModuleRoot)
 
@@ -883,19 +878,25 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 				for _, d := range dirs {
 					emuArgs = append(emuArgs, "--dir="+d)
 				}
+			} else {
+				emuArgs = append(emuArgs, "--dir=.")
 			}
 
-			dir := result.MainDir
-			if isSingleFile {
-				dir, _ = os.Getwd()
+			emuArgs = append(emuArgs, "--dir="+wd)
+			emuArgs = append(emuArgs, "--env=PWD="+wd)
+			for _, v := range environmentVars {
+				emuArgs = append(emuArgs, "--env", v)
 			}
-			emuArgs = append(emuArgs, "--dir=.")
-			emuArgs = append(emuArgs, "--dir="+dir)
-			emuArgs = append(emuArgs, "--env=PWD="+dir)
+
+			// Set this for nicer backtraces during tests, but don't override the user.
+			if _, ok := os.LookupEnv("WASMTIME_BACKTRACE_DETAILS"); !ok {
+				extraCmdEnv = append(extraCmdEnv, "WASMTIME_BACKTRACE_DETAILS=1")
+			}
+
+			emulator = append(emuArgs, emulator...)
 		}
 
-		emuArgs = append(emuArgs, emulator[1:]...)
-		args = append(emuArgs, args...)
+		args = append(emulator, args...)
 	}
 	var cmd *exec.Cmd
 	if ctx != nil {
@@ -925,7 +926,7 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 
 	// Run binary.
 	if config.Options.PrintCommands != nil {
-		config.Options.PrintCommands(cmd.Path, cmd.Args...)
+		config.Options.PrintCommands(cmd.Path, cmd.Args[1:]...)
 	}
 	err = run(cmd, result)
 	if err != nil {

src/runtime/nonhosted.go

@@ -1,4 +1,4 @@
-//go:build baremetal || js || wasm_unknown
+//go:build baremetal || wasm_unknown
 
 package runtime
 

src/runtime/runtime_tinygowasm.go

@@ -29,6 +29,44 @@ func proc_exit(exitcode uint32)
 //export __stdio_exit
 func __stdio_exit()
 
+var args []string
+
+//go:linkname os_runtime_args os.runtime_args
+func os_runtime_args() []string {
+	if args == nil {
+		// Read the number of args (argc) and the buffer size required to store
+		// all these args (argv).
+		var argc, argv_buf_size uint32
+		args_sizes_get(&argc, &argv_buf_size)
+		if argc == 0 {
+			return nil
+		}
+
+		// Obtain the command line arguments
+		argsSlice := make([]unsafe.Pointer, argc)
+		buf := make([]byte, argv_buf_size)
+		args_get(&argsSlice[0], unsafe.Pointer(&buf[0]))
+
+		// Convert the array of C strings to an array of Go strings.
+		args = make([]string, argc)
+		for i, cstr := range argsSlice {
+			length := strlen(cstr)
+			argString := _string{
+				length: length,
+				ptr:    (*byte)(cstr),
+			}
+			args[i] = *(*string)(unsafe.Pointer(&argString))
+		}
+	}
+	return args
+}
+
+//go:wasmimport wasi_snapshot_preview1 args_get
+func args_get(argv *unsafe.Pointer, argv_buf unsafe.Pointer) (errno uint16)
+
+//go:wasmimport wasi_snapshot_preview1 args_sizes_get
+func args_sizes_get(argc *uint32, argv_buf_size *uint32) (errno uint16)
+
 const (
 	putcharBufferSize = 120
 	stdout            = 1

src/runtime/runtime_wasip1.go

@@ -2,10 +2,6 @@
 
 package runtime
 
-import (
-	"unsafe"
-)
-
 type timeUnit int64
 
 // libc constructors
@@ -21,38 +17,6 @@ func init() {
 	__wasm_call_ctors()
 }
 
-var args []string
-
-//go:linkname os_runtime_args os.runtime_args
-func os_runtime_args() []string {
-	if args == nil {
-		// Read the number of args (argc) and the buffer size required to store
-		// all these args (argv).
-		var argc, argv_buf_size uint32
-		args_sizes_get(&argc, &argv_buf_size)
-		if argc == 0 {
-			return nil
-		}
-
-		// Obtain the command line arguments
-		argsSlice := make([]unsafe.Pointer, argc)
-		buf := make([]byte, argv_buf_size)
-		args_get(&argsSlice[0], unsafe.Pointer(&buf[0]))
-
-		// Convert the array of C strings to an array of Go strings.
-		args = make([]string, argc)
-		for i, cstr := range argsSlice {
-			length := strlen(cstr)
-			argString := _string{
-				length: length,
-				ptr:    (*byte)(cstr),
-			}
-			args[i] = *(*string)(unsafe.Pointer(&argString))
-		}
-	}
-	return args
-}
-
 func ticksToNanoseconds(ticks timeUnit) int64 {
 	return int64(ticks)
 }
@@ -97,12 +61,6 @@ func beforeExit() {
 
 // Implementations of WASI APIs
 
-//go:wasmimport wasi_snapshot_preview1 args_get
-func args_get(argv *unsafe.Pointer, argv_buf unsafe.Pointer) (errno uint16)
-
-//go:wasmimport wasi_snapshot_preview1 args_sizes_get
-func args_sizes_get(argc *uint32, argv_buf_size *uint32) (errno uint16)
-
 //go:wasmimport wasi_snapshot_preview1 clock_time_get
 func clock_time_get(clockid uint32, precision uint64, time *uint64) (errno uint16)
 

src/sync/mutex.go

@@ -3,12 +3,10 @@ package sync
 import (
 	"internal/task"
 	_ "unsafe"
-
-	"runtime/volatile"
 )
 
 type Mutex struct {
-	state   uint8 // Set to non-zero if locked.
+	locked  bool
 	blocked task.Stack
 }
 
@@ -16,18 +14,18 @@ type Mutex struct {
 func scheduleTask(*task.Task)
 
 func (m *Mutex) Lock() {
-	if m.islocked() {
+	if m.locked {
 		// Push self onto stack of blocked tasks, and wait to be resumed.
 		m.blocked.Push(task.Current())
 		task.Pause()
 		return
 	}
 
-	m.setlock(true)
+	m.locked = true
 }
 
 func (m *Mutex) Unlock() {
-	if !m.islocked() {
+	if !m.locked {
 		panic("sync: unlock of unlocked Mutex")
 	}
 
@@ -35,7 +33,7 @@ func (m *Mutex) Unlock() {
 	if t := m.blocked.Pop(); t != nil {
 		scheduleTask(t)
 	} else {
-		m.setlock(false)
+		m.locked = false
 	}
 }
 
@@ -45,28 +43,13 @@ func (m *Mutex) Unlock() {
 // and use of TryLock is often a sign of a deeper problem
 // in a particular use of mutexes.
 func (m *Mutex) TryLock() bool {
-	if m.islocked() {
+	if m.locked {
 		return false
 	}
 	m.Lock()
 	return true
 }
 
-func (m *Mutex) islocked() bool {
-	return volatile.LoadUint8(&m.state) != 0
-}
-
-func (m *Mutex) setlock(b bool) {
-	volatile.StoreUint8(&m.state, boolToU8(b))
-}
-
-func boolToU8(b bool) uint8 {
-	if b {
-		return 1
-	}
-	return 0
-}
-
 type RWMutex struct {
 	// waitingWriters are all of the tasks waiting for write locks.
 	waitingWriters task.Stack

src/syscall/env_libc.go

@@ -1,4 +1,4 @@
-//go:build nintendoswitch || wasip1
+//go:build js || nintendoswitch || wasip1
 
 package syscall
 

src/syscall/errno_other.go

@@ -1,4 +1,4 @@
-//go:build !wasip1 && !wasip2
+//go:build !js && !wasip1 && !wasip2
 
 package syscall
 

src/syscall/errno_wasmlibc.go

@@ -1,4 +1,4 @@
-//go:build wasip1
+//go:build js || wasip1
 
 package syscall
 

src/syscall/syscall_libc.go

@@ -1,4 +1,4 @@
-//go:build nintendoswitch || wasip1 || wasip2
+//go:build js || nintendoswitch || wasip1 || wasip2
 
 package syscall
 

src/syscall/syscall_libc_wasi.go

@@ -1,4 +1,4 @@
-//go:build wasip1 || wasip2
+//go:build js || wasip1 || wasip2
 
 package syscall
 

src/syscall/syscall_nonhosted.go

@@ -1,4 +1,4 @@
-//go:build baremetal || js || wasm_unknown
+//go:build baremetal || wasm_unknown
 
 package syscall
 

src/syscall/tables_nonhosted.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build baremetal || nintendoswitch || js || wasm_unknown
+//go:build baremetal || nintendoswitch || wasm_unknown
 
 package syscall
 

targets/wasip1.json

@@ -23,5 +23,5 @@
 	"extra-files": [
 		"src/runtime/asm_tinygowasm.S"
 	],
-	"emulator":      "wasmtime --dir={tmpDir}::/tmp {}"
+	"emulator":      "wasmtime run --dir={tmpDir}::/tmp {}"
 }

targets/wasip2.json

@@ -25,7 +25,7 @@
 	"extra-files": [
 		"src/runtime/asm_tinygowasm.S"
 	],
-	"emulator": "wasmtime --wasm component-model -Sinherit-network -Sallow-ip-name-lookup --dir={tmpDir}::/tmp {}",
+	"emulator": "wasmtime run --wasm component-model -Sinherit-network -Sallow-ip-name-lookup --dir={tmpDir}::/tmp {}",
 	"wit-package": "{root}/lib/wasi-cli/wit/",
 	"wit-world": "wasi:cli/command"
 }

targets/wasm-unknown.json

@@ -24,5 +24,5 @@
 	"extra-files": [
 		"src/runtime/asm_tinygowasm.S"
 	],
-	"emulator":      "wasmtime --dir={tmpDir}::/tmp {}"
+	"emulator":      "wasmtime run --dir={tmpDir}::/tmp {}"
 }

targets/wasm_exec.js

@@ -135,6 +135,8 @@
 
 	global.Go = class {
 		constructor() {
+			this.argv = ["js"];
+			this.env = {};
 			this._callbackTimeouts = new Map();
 			this._nextCallbackTimeoutID = 1;
 
@@ -235,9 +237,58 @@
 				return decoder.decode(new DataView(this._inst.exports.memory.buffer, ptr, len));
 			}
 
+			const storeStringArraySizes = (array, num_ptr, buf_size_ptr) => {
+				let buf_size = 0;
+				for (let s of array) {
+					buf_size += s.length + 1;
+				}
+				mem().setUint32(num_ptr, array.length, true);
+				mem().setUint32(buf_size_ptr, buf_size, true);
+			}
+
+			const storeStringArray = (array, ptrs_ptr, buf_ptr) => {
+				for (let s of array) {
+					// Put string data in buffer.
+					let data = encoder.encode(s);
+					let dest = new Uint8Array(this._inst.exports.memory.buffer, buf_ptr, data.length);
+					dest.set(data);
+					mem().setUint8(buf_ptr+data.length, 0);
+
+					// Put pointer to buffer in pointers array.
+					mem().setUint32(ptrs_ptr, buf_ptr, true);
+
+					// Advance to the next element in the array.
+					ptrs_ptr += 4;
+					buf_ptr += data.length + 1;
+				}
+			}
+
+			const envArray = () => {
+				let array = [];
+				for (let [key, value] of Object.entries(this.env)) {
+					array.push(`${key}=${value}`);
+				}
+				return array;
+			}
+
 			const timeOrigin = Date.now() - performance.now();
 			this.importObject = {
 				wasi_snapshot_preview1: {
+					args_sizes_get: (argc_ptr, argv_buf_size_ptr) => {
+						storeStringArraySizes(this.argv, argc_ptr, argv_buf_size_ptr);
+						return 0;
+					},
+					args_get: (argv_ptr, argv_buf_ptr) => {
+						storeStringArray(this.argv, argv_ptr, argv_buf_ptr);
+						return 0;
+					},
+					environ_get: (env_ptr, env_buf_ptr) => {
+						storeStringArray(envArray(), env_ptr, env_buf_ptr);
+					},
+					environ_sizes_get: (env_ptr, env_buf_size_ptr) => {
+						storeStringArraySizes(envArray(), env_ptr, env_buf_size_ptr);
+						return 0;
+					},
 					// https://github.com/WebAssembly/WASI/blob/main/phases/snapshot/docs.md#fd_write
 					fd_write: function(fd, iovs_ptr, iovs_len, nwritten_ptr) {
 						let nwritten = 0;
@@ -504,12 +555,14 @@
 		global.process.versions &&
 		!global.process.versions.electron
 	) {
-		if (process.argv.length != 3) {
+		if (process.argv.length < 3) {
 			console.error("usage: go_js_wasm_exec [wasm binary] [arguments]");
 			process.exit(1);
 		}
 
 		const go = new Go();
+		go.argv = process.argv.slice(2);
+		go.env = process.env;
 		WebAssembly.instantiate(fs.readFileSync(process.argv[2]), go.importObject).then((result) => {
 			return go.run(result.instance);
 		}).catch((err) => {