wasm: restrict supported types in go:wasmimport function signatures

Changes the set of types supported in functions declared with the
go:wasmimport directive to only allow 32 bits and 64 bits integers
and floats, as well as unsafe.Pointer in parameters only. Both the
compiler code and the standard library are updated because the new
restrictions require modifying the use of go:wasmimport in the
syscall and runtime packages.

In preparation of enabling packages outside of the standard library
to use the go:wasmimport directive, the error messages are modified
to carry more context and use ErrorfAt instead of Fatalf to avoid
printing the compiler stack trace when a function with an invalid
signature is encountered.

Fixes #59156

Change-Id: Ied8317f8ead9c28f0297060ac35a5b5255ab49db
Reviewed-on: https://go-review.googlesource.com/c/go/+/483415
Reviewed-by: Cherry Mui <[email protected]>
Reviewed-by: Johan Brandhorst-Satzkorn <[email protected]>
Reviewed-by: David Chase <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Johan Brandhorst-Satzkorn <[email protected]>

Author: achille-roussel

src/cmd/compile/internal/ssagen/abi.go

@@ -366,23 +366,48 @@ func CreateWasmImportWrapper(fn *ir.Func) bool {
 	return true
 }
 
-func toWasmFields(result *abi.ABIParamResultInfo, abiParams []abi.ABIParamAssignment) []obj.WasmField {
+func paramsToWasmFields(f *ir.Func, result *abi.ABIParamResultInfo, abiParams []abi.ABIParamAssignment) []obj.WasmField {
 	wfs := make([]obj.WasmField, len(abiParams))
 	for i, p := range abiParams {
 		t := p.Type
-		switch {
-		case t.IsInteger() && t.Size() == 4:
+		switch t.Kind() {
+		case types.TINT32, types.TUINT32:
 			wfs[i].Type = obj.WasmI32
-		case t.IsInteger() && t.Size() == 8:
+		case types.TINT64, types.TUINT64:
 			wfs[i].Type = obj.WasmI64
-		case t.IsFloat() && t.Size() == 4:
+		case types.TFLOAT32:
 			wfs[i].Type = obj.WasmF32
-		case t.IsFloat() && t.Size() == 8:
+		case types.TFLOAT64:
 			wfs[i].Type = obj.WasmF64
-		case t.IsPtr():
+		case types.TUNSAFEPTR:
 			wfs[i].Type = obj.WasmPtr
 		default:
-			base.Fatalf("wasm import has bad function signature")
+			base.ErrorfAt(f.Pos(), 0, "go:wasmimport %s %s: unsupported parameter type %s", f.WasmImport.Module, f.WasmImport.Name, t.String())
+		}
+		wfs[i].Offset = p.FrameOffset(result)
+	}
+	return wfs
+}
+
+func resultsToWasmFields(f *ir.Func, result *abi.ABIParamResultInfo, abiParams []abi.ABIParamAssignment) []obj.WasmField {
+	if len(abiParams) > 1 {
+		base.ErrorfAt(f.Pos(), 0, "go:wasmimport %s %s: too many return values", f.WasmImport.Module, f.WasmImport.Name)
+		return nil
+	}
+	wfs := make([]obj.WasmField, len(abiParams))
+	for i, p := range abiParams {
+		t := p.Type
+		switch t.Kind() {
+		case types.TINT32, types.TUINT32:
+			wfs[i].Type = obj.WasmI32
+		case types.TINT64, types.TUINT64:
+			wfs[i].Type = obj.WasmI64
+		case types.TFLOAT32:
+			wfs[i].Type = obj.WasmF32
+		case types.TFLOAT64:
+			wfs[i].Type = obj.WasmF64
+		default:
+			base.ErrorfAt(f.Pos(), 0, "go:wasmimport %s %s: unsupported result type %s", f.WasmImport.Module, f.WasmImport.Name, t.String())
 		}
 		wfs[i].Offset = p.FrameOffset(result)
 	}
@@ -419,8 +444,8 @@ func setupWasmABI(f *ir.Func) {
 		// 	(import "a_module" "add" (func (param i32 i32) (result i32)))
 		abiConfig := AbiForBodylessFuncStackMap(f)
 		abiInfo := abiConfig.ABIAnalyzeFuncType(f.Type().FuncType())
-		wi.Params = toWasmFields(abiInfo, abiInfo.InParams())
-		wi.Results = toWasmFields(abiInfo, abiInfo.OutParams())
+		wi.Params = paramsToWasmFields(f, abiInfo, abiInfo.InParams())
+		wi.Results = resultsToWasmFields(f, abiInfo, abiInfo.OutParams())
 	}
 	f.LSym.Func().WasmImport = &wi
 }

src/runtime/os_wasip1.go

@@ -48,31 +48,31 @@ func exit(code int32)
 
 //go:wasmimport wasi_snapshot_preview1 args_get
 //go:noescape
-func args_get(argv *uintptr32, argvBuf *byte) errno
+func args_get(argv, argvBuf unsafe.Pointer) errno
 
 //go:wasmimport wasi_snapshot_preview1 args_sizes_get
 //go:noescape
-func args_sizes_get(argc *size, argvBufLen *size) errno
+func args_sizes_get(argc, argvBufLen unsafe.Pointer) errno
 
 //go:wasmimport wasi_snapshot_preview1 clock_time_get
 //go:noescape
-func clock_time_get(clock_id clockid, precision timestamp, time *timestamp) errno
+func clock_time_get(clock_id clockid, precision timestamp, time unsafe.Pointer) errno
 
 //go:wasmimport wasi_snapshot_preview1 environ_get
 //go:noescape
-func environ_get(environ *uintptr32, environBuf *byte) errno
+func environ_get(environ, environBuf unsafe.Pointer) errno
 
 //go:wasmimport wasi_snapshot_preview1 environ_sizes_get
 //go:noescape
-func environ_sizes_get(environCount *size, environBufLen *size) errno
+func environ_sizes_get(environCount, environBufLen unsafe.Pointer) errno
 
 //go:wasmimport wasi_snapshot_preview1 fd_write
 //go:noescape
-func fd_write(fd int32, iovs *iovec, iovsLen size, nwritten *size) errno
+func fd_write(fd int32, iovs unsafe.Pointer, iovsLen size, nwritten unsafe.Pointer) errno
 
 //go:wasmimport wasi_snapshot_preview1 random_get
 //go:noescape
-func random_get(buf *byte, bufLen size) errno
+func random_get(buf unsafe.Pointer, bufLen size) errno
 
 type eventtype = uint8
 
@@ -140,15 +140,15 @@ func (u *subscriptionUnion) subscriptionClock() *subscriptionClock {
 
 //go:wasmimport wasi_snapshot_preview1 poll_oneoff
 //go:noescape
-func poll_oneoff(in *subscription, out *event, nsubscriptions size, nevents *size) errno
+func poll_oneoff(in, out unsafe.Pointer, nsubscriptions size, nevents unsafe.Pointer) errno
 
 func write1(fd uintptr, p unsafe.Pointer, n int32) int32 {
 	iov := iovec{
 		buf:    uintptr32(uintptr(p)),
 		bufLen: size(n),
 	}
 	var nwritten size
-	if fd_write(int32(fd), &iov, 1, &nwritten) != 0 {
+	if fd_write(int32(fd), unsafe.Pointer(&iov), 1, unsafe.Pointer(&nwritten)) != 0 {
 		throw("fd_write failed")
 	}
 	return int32(nwritten)
@@ -167,13 +167,13 @@ func usleep(usec uint32) {
 	subscription.timeout = timestamp(usec) * 1e3
 	subscription.precision = 1e3
 
-	if poll_oneoff(&in, &out, 1, &nevents) != 0 {
+	if poll_oneoff(unsafe.Pointer(&in), unsafe.Pointer(&out), 1, unsafe.Pointer(&nevents)) != 0 {
 		throw("wasi_snapshot_preview1.poll_oneoff")
 	}
 }
 
 func getRandomData(r []byte) {
-	if random_get(&r[0], size(len(r))) != 0 {
+	if random_get(unsafe.Pointer(&r[0]), size(len(r))) != 0 {
 		throw("random_get failed")
 	}
 }
@@ -182,15 +182,15 @@ func goenvs() {
 	// arguments
 	var argc size
 	var argvBufLen size
-	if args_sizes_get(&argc, &argvBufLen) != 0 {
+	if args_sizes_get(unsafe.Pointer(&argc), unsafe.Pointer(&argvBufLen)) != 0 {
 		throw("args_sizes_get failed")
 	}
 
 	argslice = make([]string, argc)
 	if argc > 0 {
 		argv := make([]uintptr32, argc)
 		argvBuf := make([]byte, argvBufLen)
-		if args_get(&argv[0], &argvBuf[0]) != 0 {
+		if args_get(unsafe.Pointer(&argv[0]), unsafe.Pointer(&argvBuf[0])) != 0 {
 			throw("args_get failed")
 		}
 
@@ -207,15 +207,15 @@ func goenvs() {
 	// environment
 	var environCount size
 	var environBufLen size
-	if environ_sizes_get(&environCount, &environBufLen) != 0 {
+	if environ_sizes_get(unsafe.Pointer(&environCount), unsafe.Pointer(&environBufLen)) != 0 {
 		throw("environ_sizes_get failed")
 	}
 
 	envs = make([]string, environCount)
 	if environCount > 0 {
 		environ := make([]uintptr32, environCount)
 		environBuf := make([]byte, environBufLen)
-		if environ_get(&environ[0], &environBuf[0]) != 0 {
+		if environ_get(unsafe.Pointer(&environ[0]), unsafe.Pointer(&environBuf[0])) != 0 {
 			throw("environ_get failed")
 		}
 
@@ -236,15 +236,15 @@ func walltime() (sec int64, nsec int32) {
 
 func walltime1() (sec int64, nsec int32) {
 	var time timestamp
-	if clock_time_get(clockRealtime, 0, &time) != 0 {
+	if clock_time_get(clockRealtime, 0, unsafe.Pointer(&time)) != 0 {
 		throw("clock_time_get failed")
 	}
 	return int64(time / 1000000000), int32(time % 1000000000)
 }
 
 func nanotime1() int64 {
 	var time timestamp
-	if clock_time_get(clockMonotonic, 0, &time) != 0 {
+	if clock_time_get(clockMonotonic, 0, unsafe.Pointer(&time)) != 0 {
 		throw("clock_time_get failed")
 	}
 	return int64(time)