wasilibc: 19 -> 20

pkgsCross.wasi32.llvmPackages: 12 -> 16

* It appears BULK_MEMORY_SOURCES no longer needs to be set to be empty
  to compile firefox. Without it, the build of wasilibc would fail if
  enableThreads is true.

* Include preliminary support for the experimental threads support in
  wasilibc which provides pthreads API. If wasilibc is built with
  support, is exposed via passthru and libcxx / libcxxabi are built with
  threads support accordingly.

  See also:
  - WebAssembly/wasi-sdk#274
  - WebAssembly/wasi-sdk#301
  - WebAssembly/wasi-sdk#314

  wasi-sdk ships it by default, but as a separate variant of libc which
  would be a hassle for us. Let's just make it optional for now.

  You can try it out using the following overlay:

      self: super: {
        wasilibc = super.wasilibc.override { enableThreads = true; };
      }

  Flags for libc++abi are copied from wasi-sdk.

pkgs/development/compilers/llvm/16/libcxx/default.nix

@@ -86,7 +86,7 @@ stdenv.mkDerivation rec {
  # libcxx appears to require unwind and doesn't pull it in via other means.
  "-DLIBCXX_ADDITIONAL_LIBRARIES=unwind"
  ] ++ lib.optionals stdenv.hostPlatform.isWasm [
- "-DLIBCXX_ENABLE_THREADS=OFF"
+ "-DLIBCXX_ENABLE_THREADS=${if stdenv.cc.libc.hasThreads then "ON" else "OFF"}"
  "-DLIBCXX_ENABLE_FILESYSTEM=OFF"
  "-DLIBCXX_ENABLE_EXCEPTIONS=OFF"
  ] ++ lib.optional (!enableShared) "-DLIBCXX_ENABLE_SHARED=OFF"

pkgs/development/compilers/llvm/16/libcxxabi/default.nix

@@ -74,10 +74,26 @@ stdenv.mkDerivation rec {
  # pkgsLLVM.libcxxabi (which uses clangNoCompilerRtWithLibc).
  "-DCMAKE_EXE_LINKER_FLAGS=-nostdlib"
  "-DCMAKE_SHARED_LINKER_FLAGS=-nostdlib"
- ] ++ lib.optionals stdenv.hostPlatform.isWasm [
- "-DLIBCXXABI_ENABLE_THREADS=OFF"
- "-DLIBCXXABI_ENABLE_EXCEPTIONS=OFF"
- ] ++ lib.optionals (!enableShared) [
+ ] ++ lib.optionals stdenv.hostPlatform.isWasm (
+ [
+ "-DLIBCXXABI_ENABLE_EXCEPTIONS=OFF"
+ # CMake tests for -fno-exceptions together with -lc++ -lc++abi which fails
+ # here, without -fno-exceptions, libc++abi is unusable later.
+ # See also: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=260005
+ # TODO(@sternenseemann): make this unconditional?
+ "-DCXX_SUPPORTS_FNO_EXCEPTIONS_FLAG=ON"
+ ]
+ ++ (if stdenv.cc.libc.hasThreads then [
+ "-DLIBCXXABI_ENABLE_THREADS=ON"
+ "-DLIBCXXABI_HAS_PTHREAD_API=ON"
+ "-DLIBCXXABI_HAS_EXTERNAL_THREAD_API=OFF"
+ "-DLIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY=OFF"
+ "-DLIBCXXABI_HAS_WIN32_THREAD_API=OFF"
+ ] else [
+ "-DLIBCXXABI_ENABLE_THREADS=OFF"
+ ])
+ )
+ ++ lib.optionals (!enableShared) [
  "-DLIBCXXABI_ENABLE_SHARED=OFF"
  ];
 

pkgs/development/libraries/wasilibc/default.nix

@@ -2,13 +2,16 @@
 , buildPackages
 , fetchFromGitHub
 , lib
+# Enable experimental wasilibc pthread support
+, enableThreads ? false
+# For tests
 , firefox-unwrapped
 , firefox-esr-unwrapped
 }:
 
 let
  pname = "wasilibc";
- version = "19";
+ version = "20";
 in
 stdenv.mkDerivation {
  inherit pname version;
@@ -17,7 +20,7 @@ stdenv.mkDerivation {
  owner = "WebAssembly";
  repo = "wasi-libc";
  rev = "refs/tags/wasi-sdk-${version}";
- hash = "sha256-yQSKoSil/C/1lIHwEO9eQKC/ye3PJIFGYjHyNDn61y4=";
+ sha256 = "0knm5ch499dksmv1k0kh7356pjd9n1gjn0p3vp9bw57mn478zp8z";
  fetchSubmodules = true;
  };
 
@@ -38,8 +41,7 @@ stdenv.mkDerivation {
  "SYSROOT_LIB:=$SYSROOT_LIB"
  "SYSROOT_INC:=$SYSROOT_INC"
  "SYSROOT_SHARE:=$SYSROOT_SHARE"
- # https://bugzilla.mozilla.org/show_bug.cgi?id=1773200
- "BULK_MEMORY_SOURCES:="
+ "THREAD_MODEL=${if enableThreads then "posix" else "single"}"
  )
 
  '';
@@ -53,8 +55,11 @@ stdenv.mkDerivation {
  ln -s $share/share/undefined-symbols.txt $out/lib/wasi.imports
  '';
 
- passthru.tests = {
- inherit firefox-unwrapped firefox-esr-unwrapped;
+ passthru = {
+ tests = {
+ inherit firefox-unwrapped firefox-esr-unwrapped;
+ };
+ hasThreads = enableThreads;
  };
 
  meta = with lib; {

pkgs/top-level/all-packages.nix

@@ -16646,7 +16646,7 @@ with pkgs;
  else if platform.isFreeBSD then 12
  else if platform.isAndroid then 12
  else if platform.isLinux then 11
- else if platform.isWasm then 12
+ else if platform.isWasm then 16
  else 14;
  # We take the "max of the mins". Why? Since those are lower bounds of the
  # supported version set, this is like intersecting those sets and then