Conditionalize use of POSIX features missing on WASI/WebAssembly

clang/lib/Driver/Driver.cpp

@@ -1578,7 +1578,7 @@ bool Driver::getCrashDiagnosticFile(StringRef ReproCrashFilename,
     CrashDiagDir = "/";
   path::append(CrashDiagDir, "Library/Logs/DiagnosticReports");
   int PID =
-#if LLVM_ON_UNIX
+#if LLVM_ON_UNIX && !defined(__wasi__)
       getpid();
 #else
       0;

llvm/cmake/config-ix.cmake

@@ -300,6 +300,7 @@ check_symbol_exists(getrlimit "sys/types.h;sys/time.h;sys/resource.h" HAVE_GETRL
 check_symbol_exists(posix_spawn spawn.h HAVE_POSIX_SPAWN)
 check_symbol_exists(pread unistd.h HAVE_PREAD)
 check_symbol_exists(sbrk unistd.h HAVE_SBRK)
+check_symbol_exists(setjmp setjmp.h HAVE_SETJMP)
 check_symbol_exists(strerror_r string.h HAVE_STRERROR_R)
 check_symbol_exists(strerror_s string.h HAVE_DECL_STRERROR_S)
 check_symbol_exists(setenv stdlib.h HAVE_SETENV)

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -217,6 +217,10 @@ elseif(FUCHSIA OR UNIX)
   else()
     set(LLVM_HAVE_LINK_VERSION_SCRIPT 1)
   endif()
+elseif(WASI)
+  set(LLVM_ON_WIN32 0)
+  set(LLVM_ON_UNIX 1)
+  set(LLVM_HAVE_LINK_VERSION_SCRIPT 0)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "Generic")
   set(LLVM_ON_WIN32 0)
   set(LLVM_ON_UNIX 0)

llvm/include/llvm/ADT/bit.h

@@ -29,7 +29,7 @@
 
 #if defined(__linux__) || defined(__GNU__) || defined(__HAIKU__) ||            \
     defined(__Fuchsia__) || defined(__EMSCRIPTEN__) || defined(__NetBSD__) ||  \
-    defined(__OpenBSD__) || defined(__DragonFly__)
+    defined(__OpenBSD__) || defined(__DragonFly__) || defined(__wasm__)
 #include <endian.h>
 #elif defined(_AIX)
 #include <sys/machine.h>

llvm/include/llvm/Config/config.h.cmake

@@ -164,6 +164,10 @@
 /* Define to 1 if you have the `sbrk' function. */
 #cmakedefine HAVE_SBRK ${HAVE_SBRK}
 
+/* Define to 1 if you have the `setjmp' function. */
+/* This function is expected to be present everywhere except for a subset of WebAssembly builds. */
+#cmakedefine HAVE_SETJMP ${HAVE_SETJMP}
+
 /* Define to 1 if you have the `setenv' function. */
 #cmakedefine HAVE_SETENV ${HAVE_SETENV}
 

llvm/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp

@@ -34,7 +34,9 @@
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
 #include <cmath>
+#if !defined(__wasi__)
 #include <csignal>
+#endif
 #include <cstdint>
 #include <cstdio>
 #include <cstring>
@@ -340,7 +342,11 @@ static GenericValue lle_X_exit(FunctionType *FT, ArrayRef<GenericValue> Args) {
 static GenericValue lle_X_abort(FunctionType *FT, ArrayRef<GenericValue> Args) {
   //FIXME: should we report or raise here?
   //report_fatal_error("Interpreted program raised SIGABRT");
+#if defined(__wasi__)
+  abort();
+#else
   raise (SIGABRT);
+#endif
   return GenericValue();
 }
 

llvm/lib/Support/CrashRecoveryContext.cpp

@@ -13,8 +13,15 @@
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/thread.h"
 #include <cassert>
+#if !defined(__wasi__)
+#include <csignal>
+#endif
 #include <mutex>
+#if HAVE_SETJMP
+// We can rely on setjmp to exist everywhere except for a subset of WebAssembly
+// builds.
 #include <setjmp.h>
+#endif
 
 using namespace llvm;
 
@@ -31,7 +38,9 @@ struct CrashRecoveryContextImpl {
   const CrashRecoveryContextImpl *Next;
 
   CrashRecoveryContext *CRC;
+#ifdef HAVE_SETJMP
   ::jmp_buf JumpBuffer;
+#endif
   volatile unsigned Failed : 1;
   unsigned SwitchedThread : 1;
   unsigned ValidJumpBuffer : 1;
@@ -50,9 +59,7 @@ struct CrashRecoveryContextImpl {
   /// Called when the separate crash-recovery thread was finished, to
   /// indicate that we don't need to clear the thread-local CurrentContext.
   void setSwitchedThread() {
-#if defined(LLVM_ENABLE_THREADS) && LLVM_ENABLE_THREADS != 0
     SwitchedThread = true;
-#endif
   }
 
   // If the function ran by the CrashRecoveryContext crashes or fails, then
@@ -72,9 +79,11 @@ struct CrashRecoveryContextImpl {
 
     CRC->RetCode = RetCode;
 
+#if HAVE_SETJMP
     // Jump back to the RunSafely we were called under.
     if (ValidJumpBuffer)
       longjmp(JumpBuffer, 1);
+#endif
 
     // Otherwise let the caller decide of the outcome of the crash. Currently
     // this occurs when using SEH on Windows with MSVC or clang-cl.
@@ -329,7 +338,16 @@ static void uninstallExceptionOrSignalHandlers() {
   }
 }
 
-#else // !_WIN32
+#elif defined(__wasi__)
+
+// WASI implementation.
+//
+// WASI traps are always fatal, and recovery is not possible. Do nothing.
+
+static void installExceptionOrSignalHandlers() {}
+static void uninstallExceptionOrSignalHandlers() {}
+
+#else // !_WIN32 && !__wasi__
 
 // Generic POSIX implementation.
 //
@@ -417,10 +435,12 @@ bool CrashRecoveryContext::RunSafely(function_ref<void()> Fn) {
     CrashRecoveryContextImpl *CRCI = new CrashRecoveryContextImpl(this);
     Impl = CRCI;
 
+#if HAVE_SETJMP
     CRCI->ValidJumpBuffer = true;
     if (setjmp(CRCI->JumpBuffer) != 0) {
       return false;
     }
+#endif
   }
 
   Fn();
@@ -467,7 +487,9 @@ bool CrashRecoveryContext::isCrash(int RetCode) {
 bool CrashRecoveryContext::throwIfCrash(int RetCode) {
   if (!isCrash(RetCode))
     return false;
-#if defined(_WIN32)
+#if defined(__wasi__)
+  abort();
+#elif defined(_WIN32)
   ::RaiseException(RetCode, 0, 0, NULL);
 #else
   llvm::sys::unregisterHandlers();

llvm/lib/Support/InitLLVM.cpp

@@ -47,6 +47,7 @@ InitLLVM::InitLLVM(int &Argc, const char **&Argv,
   // Bring stdin/stdout/stderr into a known state.
   sys::AddSignalHandler(CleanupStdHandles, nullptr);
 #endif
+#if !defined(__wasi__)
   if (InstallPipeSignalExitHandler)
     // The pipe signal handler must be installed before any other handlers are
     // registered. This is because the Unix \ref RegisterHandlers function does
@@ -59,6 +60,7 @@ InitLLVM::InitLLVM(int &Argc, const char **&Argv,
   StackPrinter.emplace(Argc, Argv);
   sys::PrintStackTraceOnErrorSignal(Argv[0]);
   install_out_of_memory_new_handler();
+#endif
 
 #ifdef __MVS__
 

llvm/lib/Support/LockFileManager.cpp

@@ -94,7 +94,7 @@ static std::error_code getHostID(SmallVectorImpl<char> &HostID) {
   StringRef UUIDRef(UUIDStr);
   HostID.append(UUIDRef.begin(), UUIDRef.end());
 
-#elif LLVM_ON_UNIX
+#elif !defined(__wasi__)
   char HostName[256];
   HostName[255] = 0;
   HostName[0] = 0;
@@ -111,7 +111,7 @@ static std::error_code getHostID(SmallVectorImpl<char> &HostID) {
 }
 
 bool LockFileManager::processStillExecuting(StringRef HostID, int PID) {
-#if LLVM_ON_UNIX && !defined(__ANDROID__)
+#if LLVM_ON_UNIX && !defined(__ANDROID__) && !defined(__wasi__)
   SmallString<256> StoredHostID;
   if (getHostID(StoredHostID))
     return true; // Conservatively assume it's executing on error.

llvm/lib/Support/Signals.cpp

@@ -273,9 +273,19 @@ static bool printMarkupStackTrace(StringRef Argv0, void **StackTrace, int Depth,
 }
 
 // Include the platform-specific parts of this class.
-#ifdef LLVM_ON_UNIX
+#if defined(__wasi__)
+// WASI does not have signals.
+void llvm::sys::AddSignalHandler(sys::SignalHandlerCallback FnPtr,
+                                 void *Cookie) {}
+void llvm::sys::RunInterruptHandlers() {}
+void sys::CleanupOnSignal(uintptr_t Context) {}
+bool llvm::sys::RemoveFileOnSignal(StringRef Filename, std::string *ErrMsg) {
+  return false;
+}
+void llvm::sys::DontRemoveFileOnSignal(StringRef Filename) {}
+void llvm::sys::DisableSystemDialogsOnCrash() {}
+#elif defined(LLVM_ON_UNIX)
 #include "Unix/Signals.inc"
-#endif
-#ifdef _WIN32
+#elif defined(_WIN32)
 #include "Windows/Signals.inc"
 #endif

llvm/lib/Support/Unix/Memory.inc

@@ -163,6 +163,11 @@ std::error_code Memory::releaseMappedMemory(MemoryBlock &M) {
 
 std::error_code Memory::protectMappedMemory(const MemoryBlock &M,
                                             unsigned Flags) {
+#if defined(__wasi__)
+  // Wasm does not allow making memory read-only or executable.
+  return std::error_code(ENOSYS, std::generic_category());
+#endif
+
   static const Align PageSize = Align(Process::getPageSizeEstimate());
   if (M.Address == nullptr || M.AllocatedSize == 0)
     return std::error_code();

llvm/lib/Support/Unix/Path.inc

@@ -32,7 +32,9 @@
 #endif
 
 #include <dirent.h>
+#if !defined(__wasi__)
 #include <pwd.h>
+#endif
 #include <sys/file.h>
 
 #ifdef __APPLE__
@@ -126,10 +128,12 @@ namespace fs {
 
 const file_t kInvalidFile = -1;
 
-#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||      \
-    defined(__FreeBSD_kernel__) || defined(__linux__) || defined(__CYGWIN__) || \
-    defined(__DragonFly__) || defined(_AIX) || defined(__GNU__) ||              \
-    (defined(__sun__) && defined(__svr4__) || defined(__HAIKU__))
+#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||     \
+    defined(__FreeBSD_kernel__) || defined(__linux__) ||                       \
+    defined(__CYGWIN__) || defined(__DragonFly__) || defined(_AIX) ||          \
+    defined(__GNU__) ||                                                        \
+    (defined(__sun__) && defined(__svr4__) || defined(__HAIKU__)) ||           \
+    defined(__wasi__)
 static int test_dir(char ret[PATH_MAX], const char *dir, const char *bin) {
   struct stat sb;
   char fullpath[PATH_MAX];
@@ -283,7 +287,7 @@ std::string getMainExecutable(const char *argv0, void *MainAddr) {
   // Fall back to the classical detection.
   if (getprogpath(exe_path, argv0))
     return exe_path;
-#elif defined(__OpenBSD__) || defined(__HAIKU__)
+#elif defined(__OpenBSD__) || defined(__HAIKU__) || defined(__wasi__)
   char exe_path[PATH_MAX];
   // argv[0] only
   if (getprogpath(exe_path, argv0) != NULL)
@@ -508,6 +512,9 @@ static bool is_local_impl(struct STATVFS &Vfs) {
 #elif defined(__EMSCRIPTEN__)
   // Emscripten doesn't currently support remote filesystem mounts.
   return true;
+#elif defined(__wasi__)
+  // WASI doesn't currently support remote filesystem mounts.
+  return true;
 #elif defined(__HAIKU__)
   // Haiku doesn't expose this information.
   return false;
@@ -673,6 +680,11 @@ static void expandTildeExpr(SmallVectorImpl<char> &Path) {
     return;
   }
 
+#if defined(__wasi__)
+  // No access to password database, return back the original path.
+  (void)Remainder;
+  return;
+#else
   // This is a string of the form ~username/, look up this user's entry in the
   // password database.
   std::unique_ptr<char[]> Buf;
@@ -694,6 +706,7 @@ static void expandTildeExpr(SmallVectorImpl<char> &Path) {
   Path.clear();
   Path.append(Entry->pw_dir, Entry->pw_dir + strlen(Entry->pw_dir));
   llvm::sys::path::append(Path, Storage);
+#endif
 }
 
 void expand_tilde(const Twine &path, SmallVectorImpl<char> &dest) {
@@ -770,11 +783,15 @@ std::error_code status(int FD, file_status &Result) {
 }
 
 unsigned getUmask() {
+#if defined(__wasi__)
+  return 0022;
+#else
   // Chose arbitary new mask and reset the umask to the old mask.
   // umask(2) never fails so ignore the return of the second call.
   unsigned Mask = ::umask(0);
   (void)::umask(Mask);
   return Mask;
+#endif
 }
 
 std::error_code setPermissions(const Twine &Path, perms Permissions) {
@@ -880,7 +897,7 @@ void mapped_file_region::dontNeedImpl() {
   assert(Mode == mapped_file_region::readonly);
   if (!Mapping)
     return;
-#if defined(__MVS__) || defined(_AIX)
+#if defined(__MVS__) || defined(_AIX) || defined(__wasi__)
     // If we don't have madvise, or it isn't beneficial, treat this as a no-op.
 #elif defined(POSIX_MADV_DONTNEED)
   ::posix_madvise(Mapping, Size, POSIX_MADV_DONTNEED);
@@ -1224,6 +1241,9 @@ Expected<size_t> readNativeFileSlice(file_t FD, MutableArrayRef<char> Buf,
 }
 
 std::error_code tryLockFile(int FD, std::chrono::milliseconds Timeout) {
+#if defined(__wasi__)
+  return std::error_code(ENOSYS, std::generic_category());
+#else
   auto Start = std::chrono::steady_clock::now();
   auto End = Start + Timeout;
   do {
@@ -1241,9 +1261,13 @@ std::error_code tryLockFile(int FD, std::chrono::milliseconds Timeout) {
     usleep(1000);
   } while (std::chrono::steady_clock::now() < End);
   return make_error_code(errc::no_lock_available);
+#endif
 }
 
 std::error_code lockFile(int FD) {
+#if defined(__wasi__)
+  return std::error_code(ENOSYS, std::generic_category());
+#else
   struct flock Lock;
   memset(&Lock, 0, sizeof(Lock));
   Lock.l_type = F_WRLCK;
@@ -1253,9 +1277,13 @@ std::error_code lockFile(int FD) {
   if (::fcntl(FD, F_SETLKW, &Lock) != -1)
     return std::error_code();
   return errnoAsErrorCode();
+#endif
 }
 
 std::error_code unlockFile(int FD) {
+#if defined(__wasi__)
+  return std::error_code(ENOSYS, std::generic_category());
+#else
   struct flock Lock;
   Lock.l_type = F_UNLCK;
   Lock.l_whence = SEEK_SET;
@@ -1264,6 +1292,7 @@ std::error_code unlockFile(int FD) {
   if (::fcntl(FD, F_SETLK, &Lock) != -1)
     return std::error_code();
   return errnoAsErrorCode();
+#endif
 }
 
 std::error_code closeFile(file_t &F) {
@@ -1335,11 +1364,15 @@ std::error_code real_path(const Twine &path, SmallVectorImpl<char> &dest,
 }
 
 std::error_code changeFileOwnership(int FD, uint32_t Owner, uint32_t Group) {
+#if defined(__wasi__)
+  return std::error_code(ENOTSUP, std::generic_category());
+#else
   auto FChown = [&]() { return ::fchown(FD, Owner, Group); };
   // Retry if fchown call fails due to interruption.
   if ((sys::RetryAfterSignal(-1, FChown)) < 0)
     return errnoAsErrorCode();
   return std::error_code();
+#endif
 }
 
 } // end namespace fs
@@ -1349,6 +1382,7 @@ namespace path {
 bool home_directory(SmallVectorImpl<char> &result) {
   std::unique_ptr<char[]> Buf;
   char *RequestedDir = getenv("HOME");
+#if !defined(__wasi__)
   if (!RequestedDir) {
     long BufSize = sysconf(_SC_GETPW_R_SIZE_MAX);
     if (BufSize <= 0)
@@ -1360,6 +1394,7 @@ bool home_directory(SmallVectorImpl<char> &result) {
     if (pw && pw->pw_dir)
       RequestedDir = pw->pw_dir;
   }
+#endif
   if (!RequestedDir)
     return false;