From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Bertalan <dani@danielbertalan.dev>
Date: Thu, 14 Apr 2022 09:54:22 +0200
Subject: [PATCH] [Support] Add support for building LLVM on SerenityOS

Adds SerenityOS `#ifdef`s for platform-specific code.

We stub out wait4, as SerenityOS doesn't support querying a child
process's resource usage information.
---
 llvm/include/llvm/Support/SwapByteOrder.h | 2 +-
 llvm/lib/Support/Unix/Path.inc            | 5 ++++-
 llvm/lib/Support/Unix/Program.inc         | 9 ++++++++-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/llvm/include/llvm/Support/SwapByteOrder.h b/llvm/include/llvm/Support/SwapByteOrder.h
index 9dd08665b..8915f92e8 100644
--- a/llvm/include/llvm/Support/SwapByteOrder.h
+++ b/llvm/include/llvm/Support/SwapByteOrder.h
@@ -20,7 +20,7 @@
 #include <type_traits>
 
 #if defined(__linux__) || defined(__GNU__) || defined(__HAIKU__) ||            \
-    defined(__Fuchsia__) || defined(__EMSCRIPTEN__)
+    defined(__Fuchsia__) || defined(__EMSCRIPTEN__) || defined(__serenity__)
 #include <endian.h>
 #elif defined(_AIX)
 #include <sys/machine.h>
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 3efcad4f2..4f83d0e76 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -112,7 +112,7 @@ typedef uint_t uint;
 #endif
 
 #if defined(__NetBSD__) || defined(__DragonFly__) || defined(__GNU__) ||       \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__serenity__)
 #define STATVFS_F_FLAG(vfs) (vfs).f_flag
 #else
 #define STATVFS_F_FLAG(vfs) (vfs).f_flags
@@ -506,6 +506,9 @@ static bool is_local_impl(struct STATVFS &Vfs) {
 #elif defined(__HAIKU__)
   // Haiku doesn't expose this information.
   return false;
+#elif defined(__serenity__)
+  // Serenity doesn't yet support remote filesystem mounts.
+  return false;
 #elif defined(__sun)
   // statvfs::f_basetype contains a null-terminated FSType name of the mounted
   // target
diff --git a/llvm/lib/Support/Unix/Program.inc b/llvm/lib/Support/Unix/Program.inc
index 897e22711..23965a1a1 100644
--- a/llvm/lib/Support/Unix/Program.inc
+++ b/llvm/lib/Support/Unix/Program.inc
@@ -340,7 +340,7 @@ static bool Execute(ProcessInfo &PI, StringRef Program,
 namespace llvm {
 namespace sys {
 
-#ifndef _AIX
+#if !defined(_AIX) && !defined(__serenity__)
 using ::wait4;
 #else
 static pid_t(wait4)(pid_t pid, int *status, int options, struct rusage *usage);
@@ -383,6 +383,13 @@ pid_t(llvm::sys::wait4)(pid_t pid, int *status, int options,
 }
 #endif
 
+#ifdef __serenity__
+pid_t (llvm::sys::wait4)(pid_t pid, int *status, int options,
+                         struct rusage*) {
+  return ::waitpid(pid, status, options);
+}
+#endif
+
 ProcessInfo llvm::sys::Wait(const ProcessInfo &PI,
                             std::optional<unsigned> SecondsToWait,
                             std::string *ErrMsg,