[wasm][test] Fix build of StdlibUnittest on WASI

WASI platform doesn't support crash interception and spawning
threads/processes. So this patch disables interception support and
subprocess spawning. The later patch will disable crash tests in each
test case.

Author: kateinoigakukun

stdlib/private/StdlibUnittest/InterceptTraps.cpp

@@ -50,8 +50,6 @@ static void CrashCatcher(int Sig) {
   _exit(0);
 }
 
-#endif // __wasi__
-
 #if defined(_WIN32)
 static LONG WINAPI
 VectoredCrashHandler(PEXCEPTION_POINTERS ExceptionInfo) {
@@ -92,6 +90,8 @@ void installTrapInterceptor() {
   signal(SIGBUS,  CrashCatcher);
   signal(SIGSYS,  CrashCatcher);
 #endif
-}
 
 #endif // !defined(__wasi__)
+}
+
+#endif // !defined(__wasi__)

stdlib/private/StdlibUnittest/RaceTest.swift

@@ -38,7 +38,9 @@
 
 import SwiftPrivate
 import SwiftPrivateLibcExtras
+#if !os(WASI)
 import SwiftPrivateThreadExtras
+#endif
 #if canImport(Darwin)
 import Darwin
 #elseif canImport(Glibc)

stdlib/private/StdlibUnittest/StdlibUnittest.swift

@@ -12,7 +12,9 @@
 
 
 import SwiftPrivate
+#if !os(WASI)
 import SwiftPrivateThreadExtras
+#endif
 import SwiftPrivateLibcExtras
 
 #if canImport(Darwin)
@@ -22,6 +24,8 @@ import Foundation
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif os(WASI)
+import WASILibc
 #elseif os(Windows)
 import CRT
 import WinSDK
@@ -35,6 +39,12 @@ import ObjectiveC
 import _Concurrency
 #endif
 
+#if os(WASI)
+let platformSupportSpawnChild = false
+#else
+let platformSupportSpawnChild = true
+#endif
+
 extension String {
   /// Returns the lines in `self`.
   public var _lines : [String] {
@@ -855,8 +865,10 @@ var _testSuiteNameToIndex: [String : Int] = [:]
 let _stdlibUnittestStreamPrefix = "__STDLIB_UNITTEST__"
 let _crashedPrefix = "CRASHED:"
 
+#if !os(WASI)
 @_silgen_name("installTrapInterceptor")
 func _installTrapInterceptor()
+#endif
 
 #if _runtime(_ObjC)
 @objc protocol _StdlibUnittestNSException {
@@ -867,7 +879,9 @@ func _installTrapInterceptor()
 // Avoid serializing references to objc_setUncaughtExceptionHandler in SIL.
 @inline(never)
 func _childProcess() {
+#if !os(WASI)
   _installTrapInterceptor()
+#endif
 
 #if _runtime(_ObjC)
   objc_setUncaughtExceptionHandler {
@@ -923,7 +937,9 @@ func _childProcess() {
 @available(SwiftStdlib 5.1, *)
 @inline(never)
 func _childProcessAsync() async {
+#if !os(WASI)
   _installTrapInterceptor()
+#endif
 
 #if _runtime(_ObjC)
   objc_setUncaughtExceptionHandler {
@@ -1724,7 +1740,7 @@ public func runAllTests() {
   if _isChildProcess {
     _childProcess()
   } else {
-    var runTestsInProcess: Bool = false
+    var runTestsInProcess: Bool = !platformSupportSpawnChild
     var filter: String?
     var args = [String]()
     var i = 0
@@ -1794,7 +1810,7 @@ public func runAllTestsAsync() async {
   if _isChildProcess {
     await _childProcessAsync()
   } else {
-    var runTestsInProcess: Bool = false
+    var runTestsInProcess: Bool = !platformSupportSpawnChild
     var filter: String?
     var args = [String]()
     var i = 0