vkd3d and dxvk integration (#2823)

* Add d3d sources for linux builds

* Return NOT_IMPLEMENTED for shared handle support on Linux

* Enable DirectX api on Linux

* Do not report DX11 support without FXC

* Initial version of SynchAPI emulation

* Neaten dx library name handling

* Neaten and use posix-synchapi

* Add premake option for DirectX on Vulkan

* s/SLANG_ENABLE_VKD3D_PROTON/SLANG_ENABLE_VKD3D

* Skip failing tests on vkd3d

* Regenerate vs projects

* Silence unused var warning

15 files changed, 600 insertions, 33 deletions

diff --git a/build/visual-studio/gfx/gfx.vcxproj b/build/visual-studio/gfx/gfx.vcxproj
index 583d78e25..3198cd6e1 100644
--- a/build/visual-studio/gfx/gfx.vcxproj
+++ b/build/visual-studio/gfx/gfx.vcxproj
@@ -372,6 +372,7 @@ IF EXIST "$(SolutionDir)tools\gfx\slang.slang"\ (xcopy /Q /E /Y /I "$(SolutionDi
     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-framebuffer.h" />

     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-helper-functions.h" />

     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-pipeline-state.h" />

+    <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-posix-synchapi.h" />

     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-query.h" />

     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-render-pass.h" />

     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-resource-views.h" />

@@ -490,6 +491,7 @@ IF EXIST "$(SolutionDir)tools\gfx\slang.slang"\ (xcopy /Q /E /Y /I "$(SolutionDi
     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-fence.cpp" />

     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-helper-functions.cpp" />

     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-pipeline-state.cpp" />

+    <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-posix-synchapi.cpp" />

     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-query.cpp" />

     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-render-pass.cpp" />

     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-resource-views.cpp" />

diff --git a/build/visual-studio/gfx/gfx.vcxproj.filters b/build/visual-studio/gfx/gfx.vcxproj.filters
index 1a7ed3d03..c4fcd6046 100644
--- a/build/visual-studio/gfx/gfx.vcxproj.filters
+++ b/build/visual-studio/gfx/gfx.vcxproj.filters
@@ -183,6 +183,9 @@
     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-pipeline-state.h">

       <Filter>Header Files</Filter>

     </ClInclude>

+    <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-posix-synchapi.h">

+      <Filter>Header Files</Filter>

+    </ClInclude>

     <ClInclude Include="..\..\..\tools\gfx\d3d12\d3d12-query.h">

       <Filter>Header Files</Filter>

     </ClInclude>

@@ -533,6 +536,9 @@
     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-pipeline-state.cpp">

       <Filter>Source Files</Filter>

     </ClCompile>

+    <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-posix-synchapi.cpp">

+      <Filter>Source Files</Filter>

+    </ClCompile>

     <ClCompile Include="..\..\..\tools\gfx\d3d12\d3d12-query.cpp">

       <Filter>Source Files</Filter>

     </ClCompile>

diff --git a/premake5.lua b/premake5.lua
index 7226d18ad..06da86754 100644
--- a/premake5.lua
+++ b/premake5.lua
@@ -212,6 +212,14 @@ newoption {
     allowed     = { { "true", "True"}, { "false", "False" } }
 }
 
+newoption {
+    trigger     = "dx-on-vk",
+    description = "(Optional) If true will use dxvk and vkd3d-proton for DirectX support",
+    value       = "bool",
+    default     = "false",
+    allowed     = { { "true", "True"}, { "false", "False" } }
+}
+
 buildLocation = _OPTIONS["build-location"]
 executeBinary = (_OPTIONS["execute-binary"] == "true")
 buildGlslang = (_OPTIONS["build-glslang"] == "true")
@@ -227,6 +235,7 @@ deployLLVM = (_OPTIONS["deploy-slang-llvm"] == "true")
 deployGLSLang = (_OPTIONS["deploy-slang-glslang"] == "true")
 fullDebugValidation = (_OPTIONS["full-debug-validation"] == "true")
 enableAsan = (_OPTIONS["enable-asan"] == "true")
+dxOnVk = (_OPTIONS["dx-on-vk"] == "true")
 
 -- If stdlib embedding is enabled, disable stdlib source embedding by default
 disableStdlibSource = enableEmbedStdLib
@@ -396,6 +405,10 @@ workspace "slang"
         -- files which may be included by another project
         defines { "WIN32_LEAN_AND_MEAN", "VC_EXTRALEAN", "NOMINMAX" }
 
+        if dxOnVk then
+            defines { "SLANG_CONFIG_DX_ON_VK" }
+        end
+
 function dump(o)
     if type(o) == 'table' then
         local s = '{ '
@@ -1028,6 +1041,11 @@ tool "gfx"
     else
         -- Linux like
         addSourceDir "tools/gfx/vulkan"
+        if dxOnVk then
+            addSourceDir "tools/gfx/d3d"
+            addSourceDir "tools/gfx/d3d11"
+            addSourceDir "tools/gfx/d3d12"
+        end
         --addSourceDir "tools/gfx/open-gl"
     end
 
diff --git a/slang.h b/slang.h
index 31a98481a..89ef4ce4e 100644
--- a/slang.h
+++ b/slang.h
@@ -167,27 +167,29 @@ Any platforms not detected by the above logic are now now explicitly zeroed out.
 #define SLANG_UNIX_FAMILY (SLANG_LINUX_FAMILY || SLANG_APPLE_FAMILY) /* shortcut for unix/posix platforms */
 
 /* Macros concerning DirectX */
+#if !defined(SLANG_CONFIG_DX_ON_VK) || !SLANG_CONFIG_DX_ON_VK
+#    define SLANG_ENABLE_DXVK 0
+#    define SLANG_ENABLE_VKD3D 0
+#else
+#    define SLANG_ENABLE_DXVK 1
+#    define SLANG_ENABLE_VKD3D 1
+#endif
+
 #if SLANG_WINDOWS_FAMILY
 #    define SLANG_ENABLE_DIRECTX 1
 #    define SLANG_ENABLE_DXGI_DEBUG 1
 #    define SLANG_ENABLE_DXBC_SUPPORT 1
 #    define SLANG_ENABLE_PIX 1
-#    define SLANG_ENABLE_DXVK 0
-#    define SLANG_ENABLE_VKD3D_PROTON 0
 #elif SLANG_LINUX_FAMILY
-#    define SLANG_ENABLE_DIRECTX 0
+#    define SLANG_ENABLE_DIRECTX (SLANG_ENABLE_DXVK || SLANG_ENABLE_VKD3D)
 #    define SLANG_ENABLE_DXGI_DEBUG 0
 #    define SLANG_ENABLE_DXBC_SUPPORT 0
 #    define SLANG_ENABLE_PIX 0
-#    define SLANG_ENABLE_DXVK 1
-#    define SLANG_ENABLE_VKD3D_PROTON 1
 #else
 #    define SLANG_ENABLE_DIRECTX 0
 #    define SLANG_ENABLE_DXGI_DEBUG 0
 #    define SLANG_ENABLE_DXBC_SUPPORT 0
 #    define SLANG_ENABLE_PIX 0
-#    define SLANG_ENABLE_DXVK 0
-#    define SLANG_ENABLE_VKD3D_PROTON 0
 #endif
 
 /* Macro for declaring if a method is no throw. Should be set before the return parameter. */
diff --git a/source/compiler-core/slang-fxc-compiler.cpp b/source/compiler-core/slang-fxc-compiler.cpp
index 4153585d3..b3b952796 100644
--- a/source/compiler-core/slang-fxc-compiler.cpp
+++ b/source/compiler-core/slang-fxc-compiler.cpp
@@ -363,7 +363,8 @@ SlangResult FXCDownstreamCompiler::convert(IArtifact* from, const ArtifactDesc&
 {
     ComPtr<ISlangSharedLibrary> library;
 
-    SLANG_RETURN_ON_FAIL(DownstreamCompilerUtil::loadSharedLibrary(path, loader, nullptr, "d3dcompiler_47", library));
+    const char* const libName = "d3dcompiler_47";
+    SLANG_RETURN_ON_FAIL(DownstreamCompilerUtil::loadSharedLibrary(path, loader, nullptr, libName, library));
 
     SLANG_ASSERT(library);
     if (!library)
diff --git a/source/core/slang-render-api-util.cpp b/source/core/slang-render-api-util.cpp
index ca58091af..334e9a9d1 100644
--- a/source/core/slang-render-api-util.cpp
+++ b/source/core/slang-render-api-util.cpp
@@ -245,7 +245,7 @@ static Token nextToken(Slang::UnownedStringSlice& textInOut, Slang::UnownedStrin
     return RenderApiType::Unknown;
 }
 
-#if SLANG_WINDOWS_FAMILY
+#if SLANG_ENABLE_DIRECTX
 static bool _canLoadSharedLibrary(const char* libName)
 {
     SharedLibrary::Handle handle;
@@ -266,18 +266,16 @@ static bool _canLoadSharedLibrary(const char* libName)
 #if SLANG_WINDOWS_FAMILY
         case RenderApiType::OpenGl: return _canLoadSharedLibrary("opengl32");
         case RenderApiType::Vulkan: return _canLoadSharedLibrary("vulkan-1") || _canLoadSharedLibrary("vk_swiftshader");
-        case RenderApiType::D3D11:  return _canLoadSharedLibrary("d3d11");
-        case RenderApiType::D3D12:  return _canLoadSharedLibrary("d3d12");
 #elif SLANG_UNIX_FAMILY
-        case RenderApiType::D3D11:  return false;
-        case RenderApiType::D3D12:  return false;
-        // The below can be used once they're confirmed working with gfx
-        // case RenderApiType::D3D11:  return _canLoadSharedLibrary("dxvk_d3d11");
-        // case RenderApiType::D3D12:  return _canLoadSharedLibrary("vkd3d-proton-d3d12");
-
         case RenderApiType::OpenGl: return true;
         case RenderApiType::Vulkan: return true;
 #endif
+
+#if SLANG_ENABLE_DIRECTX
+        case RenderApiType::D3D11:  return _canLoadSharedLibrary(SLANG_ENABLE_DXVK ? "dxvk_d3d11" : "d3d11");
+        case RenderApiType::D3D12:  return _canLoadSharedLibrary(SLANG_ENABLE_VKD3D ? "vkd3d-proton-d3d12" : "d3d12");
+#endif
+
         case RenderApiType::CPU:    return true;
         // We'll assume CUDA is available, and if not, trying to create it will detect it
         case RenderApiType::CUDA:   return true;
diff --git a/tools/gfx-unit-test/copy-texture-tests.cpp b/tools/gfx-unit-test/copy-texture-tests.cpp
index 6a9d39d22..0129dd818 100644
--- a/tools/gfx-unit-test/copy-texture-tests.cpp
+++ b/tools/gfx-unit-test/copy-texture-tests.cpp
@@ -744,12 +744,23 @@ namespace gfx_test
     template<typename T>
     void copyTextureTestImpl(IDevice* device, UnitTestContext* context)
     {
+        const bool isVkd3d = SLANG_ENABLE_VKD3D &&
+            strcmp(device->getDeviceInfo().apiName, "Direct3D 12") == 0;
+
         // Skip Type::Unknown and Type::Buffer as well as Format::Unknown
         // TODO: Add support for TextureCube
         for (uint32_t i = 2; i < (uint32_t)ITextureResource::Type::_Count - 1; ++i)
         {
             for (uint32_t j = 1; j < (uint32_t)Format::_Count; ++j)
             {
+                // Fails validation VUID-VkImageCreateInfo-imageCreateMaxMipLevels-02251
+                if(isVkd3d && ((Format)j == Format::R32G32B32_TYPELESS ||
+                               (Format)j == Format::R32G32B32_FLOAT ||
+                               (Format)j == Format::R32G32B32_UINT ||
+                               (Format)j == Format::R32G32B32_SINT))
+                {
+                    continue;
+                }
                 auto type = (ITextureResource::Type)i;
                 auto format = (Format)j;
                 auto validationFormat = getValidationTextureFormat(format);
diff --git a/tools/gfx/d3d/d3d-util.cpp b/tools/gfx/d3d/d3d-util.cpp
index aff610796..0257ede1b 100644
--- a/tools/gfx/d3d/d3d-util.cpp
+++ b/tools/gfx/d3d/d3d-util.cpp
@@ -431,15 +431,20 @@ bool D3DUtil::isTypeless(DXGI_FORMAT format)
     static pD3DCompile compileFunc = nullptr;
     if (!compileFunc)
     {
+        // On Linux, vkd3d-utils isn't suitable as a unix replacement for fxc
+        // due to at least the following missing feature:
+        // https://bugs.winehq.org/show_bug.cgi?id=54872
+
         // TODO(tfoley): maybe want to search for one of a few versions of the DLL
-        HMODULE compilerModule = LoadLibraryA("d3dcompiler_47.dll");
-        if (!compilerModule)
+        const char* const libName = "d3dcompiler_47";
+        SharedLibrary::Handle compilerModule;
+        if (SLANG_FAILED(SharedLibrary::load(libName, compilerModule)))
         {
-            fprintf(stderr, "error: failed load 'd3dcompiler_47.dll'\n");
+            fprintf(stderr, "error: failed to load '%s'\n", libName);
             return SLANG_FAIL;
         }
 
-        compileFunc = (pD3DCompile)GetProcAddress(compilerModule, "D3DCompile");
+        compileFunc = (pD3DCompile)SharedLibrary::findSymbolAddressByName(compilerModule, "D3DCompile");
         if (!compileFunc)
         {
             fprintf(stderr, "error: failed load symbol 'D3DCompile'\n");
@@ -488,17 +493,14 @@ bool D3DUtil::isTypeless(DXGI_FORMAT format)
 
 /* static */SharedLibrary::Handle D3DUtil::getDxgiModule()
 {
-#if SLANG_ENABLE_DXVK
-    const char* const libPath = "dxvk_dxgi";
-#else
-    const char* const libPath = "dxgi";
-#endif
+    const char* const libName = SLANG_ENABLE_DXVK ? "dxvk_dxgi" : "dxgi";
+
     static SharedLibrary::Handle s_dxgiModule = [&](){
         SharedLibrary::Handle h = nullptr;
-        SharedLibrary::load(libPath, h);
+        SharedLibrary::load(libName, h);
         if (!h)
         {
-            fprintf(stderr, "error: failed to load dll '%s'\n", libPath);
+            fprintf(stderr, "error: failed to load dll '%s'\n", libName);
         }
         return h;
     }();
diff --git a/tools/gfx/d3d11/d3d11-device.cpp b/tools/gfx/d3d11/d3d11-device.cpp
index 4ab26725e..c10a608dc 100644
--- a/tools/gfx/d3d11/d3d11-device.cpp
+++ b/tools/gfx/d3d11/d3d11-device.cpp
@@ -47,11 +47,7 @@ SlangResult DeviceImpl::initialize(const Desc& desc)
 
     // Rather than statically link against D3D, we load it dynamically.
     SharedLibrary::Handle d3dModule;
-#if SLANG_ENABLE_DXVK
-    const char* libName = "dxvk_d3d11";
-#else
-    const char* libName = "d3d11";
-#endif
+    const char* libName = SLANG_ENABLE_DXVK ? "dxvk_d3d11" : "d3d11";
     if (SLANG_FAILED(SharedLibrary::load(libName, d3dModule)))
     {
         fprintf(stderr, "error: failed to load '%s'\n", libName);
diff --git a/tools/gfx/d3d12/d3d12-base.h b/tools/gfx/d3d12/d3d12-base.h
index 52e8d4623..0e648f9c4 100644
--- a/tools/gfx/d3d12/d3d12-base.h
+++ b/tools/gfx/d3d12/d3d12-base.h
@@ -13,6 +13,7 @@
 #include "core/slang-chunked-list.h"
 #include "d3d12-descriptor-heap.h"
 #include "d3d12-resource.h"
+#include "d3d12-posix-synchapi.h"
 
 #pragma push_macro("WIN32_LEAN_AND_MEAN")
 #pragma push_macro("NOMINMAX")
diff --git a/tools/gfx/d3d12/d3d12-buffer.cpp b/tools/gfx/d3d12/d3d12-buffer.cpp
index 42babfae6..7d3376607 100644
--- a/tools/gfx/d3d12/d3d12-buffer.cpp
+++ b/tools/gfx/d3d12/d3d12-buffer.cpp
@@ -35,6 +35,9 @@ Result BufferResourceImpl::getNativeResourceHandle(InteropHandle* outHandle)
 
 Result BufferResourceImpl::getSharedHandle(InteropHandle* outHandle)
 {
+#if !SLANG_WINDOWS_FAMILY
+    return SLANG_E_NOT_IMPLEMENTED;
+#else
     // Check if a shared handle already exists for this resource.
     if (sharedHandle.handleValue != 0)
     {
@@ -51,6 +54,7 @@ Result BufferResourceImpl::getSharedHandle(InteropHandle* outHandle)
     outHandle->api = InteropHandleAPI::D3D12;
     sharedHandle = *outHandle;
     return SLANG_OK;
+#endif
 }
 
 Result BufferResourceImpl::map(MemoryRange* rangeToRead, void** outPointer)
diff --git a/tools/gfx/d3d12/d3d12-fence.cpp b/tools/gfx/d3d12/d3d12-fence.cpp
index be3d94fcd..124d9354c 100644
--- a/tools/gfx/d3d12/d3d12-fence.cpp
+++ b/tools/gfx/d3d12/d3d12-fence.cpp
@@ -47,6 +47,9 @@ Result FenceImpl::setCurrentValue(uint64_t value)
 
 Result FenceImpl::getSharedHandle(InteropHandle* outHandle)
 {
+#if !SLANG_WINDOWS_FAMILY
+    return SLANG_E_NOT_IMPLEMENTED;
+#else
     // Check if a shared handle already exists.
     if (sharedHandle.handleValue != 0)
     {
@@ -61,6 +64,7 @@ Result FenceImpl::getSharedHandle(InteropHandle* outHandle)
     outHandle->api = InteropHandleAPI::D3D12;
     sharedHandle = *outHandle;
     return SLANG_OK;
+#endif
 }
 
 Result FenceImpl::getNativeHandle(InteropHandle* outNativeHandle)
diff --git a/tools/gfx/d3d12/d3d12-posix-synchapi.cpp b/tools/gfx/d3d12/d3d12-posix-synchapi.cpp
new file mode 100644
index 000000000..a46e96141
--- /dev/null
+++ b/tools/gfx/d3d12/d3d12-posix-synchapi.cpp
@@ -0,0 +1,452 @@
+#include "d3d12-posix-synchapi.h"
+
+#include "slang.h"
+
+#if SLANG_LINUX_FAMILY
+
+#include "core/slang-common.h"
+
+#include <fcntl.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <sys/poll.h>
+#include <sys/timerfd.h>
+#include <unistd.h>
+
+#include <cerrno>
+
+// To keep aligned with the d3d12 API, we store file descriptors in the low 32
+// bits of HANDLEs.
+static int _handleToFD(HANDLE h)
+{
+    auto i = reinterpret_cast<std::intptr_t>(h);
+    int fd = static_cast<int>(i);
+    return fd;
+}
+
+static int _handleToFlags(HANDLE h)
+{
+    auto i = reinterpret_cast<std::intptr_t>(h) >> 32;
+    int flags = static_cast<int>(i);
+    return flags;
+}
+
+static HANDLE _fdToHandle(int fd, int flags)
+{
+    static_assert(sizeof(int) <= 4);
+    static_assert(sizeof(std::intptr_t) >= 8);
+    return reinterpret_cast<HANDLE>(static_cast<std::intptr_t>(flags) << 32 | fd);
+}
+
+
+HANDLE CreateEventEx(
+    LPSECURITY_ATTRIBUTES lpEventAttributes,
+    LPCSTR                lpName,
+    DWORD                 dwFlags,
+    DWORD                 dwDesiredAccess)
+{
+    int fd = ::eventfd(dwFlags & CREATE_EVENT_INITIAL_SET ? 1 : 0, EFD_CLOEXEC | EFD_NONBLOCK);
+    // Make sure not to return a zero handle, duplicate the fd if necessary
+    if(fd == 0)
+    {
+        int nextFd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
+        if(fcntl(nextFd, F_SETFL, O_NONBLOCK) == -1)
+        {
+            close(nextFd);
+            nextFd = -1;
+        }
+        close(fd);
+        fd = nextFd;
+    }
+    return fd == -1 ? nullptr : _fdToHandle(fd, dwFlags);
+}
+
+BOOL CloseHandle(HANDLE h)
+{
+    if(h == 0)
+    {
+        return 1;
+    }
+    // TODO: Windows does reference counting, how to, dupfd?
+    return ::close(_handleToFD(h)) == 0;
+    return 1;
+}
+
+BOOL ResetEvent(HANDLE h)
+{
+    int fd = _handleToFD(h);
+    pollfd pfd{fd, POLLIN, 0};
+    uint64_t x;
+    int r = 0;
+    int nEvents = poll(&pfd, 1, 0);
+    if(pfd.revents != POLLIN)
+    {
+        // Nothing to read, already reset
+        return 1;
+    }
+    if(nEvents != 1)
+    {
+        return 0;
+    }
+    r = read(fd, &x, sizeof(x));
+    if(r == sizeof(x))
+    {
+        // We reset it
+        return 1;
+    }
+    if(r == -1 && errno == EAGAIN)
+    {
+        // Something else reset it
+        return 1;
+    }
+    return 0;
+}
+
+BOOL SetEvent(HANDLE h)
+{
+    int fd = _handleToFD(h);
+    pollfd pfd{fd, POLLOUT, 0};
+    for(;;)
+    {
+        int nEvents = poll(&pfd, 1, -1);
+        SLANG_ASSERT(nEvents != -1);
+        SLANG_ASSERT(nEvents != 0); // shouldn't have timed out
+        const uint64_t one = 1;
+        int w = ::write(fd, &one, sizeof(one));
+        if(w == sizeof(one))
+        {
+            return 1;
+        }
+        if(errno != EAGAIN)
+        {
+            return 0;
+        }
+    }
+}
+
+DWORD WaitForSingleObject(HANDLE h, DWORD ms)
+{
+    int fd = _handleToFD(h);
+    bool manualReset = _handleToFlags(h) & CREATE_EVENT_MANUAL_RESET;
+    pollfd pfd{fd, POLLIN, 0};
+    uint64_t x;
+    int r = 0;
+    int nEvents = poll(&pfd, 1, ms);
+    if(pfd.revents != POLLIN)
+    {
+        return WAIT_FAILED;
+    }
+    if(nEvents == -1)
+    {
+        return WAIT_FAILED;
+    }
+    if (nEvents == 0)
+    {
+        return WAIT_TIMEOUT;
+    }
+    if(manualReset)
+    {
+        return WAIT_OBJECT_0;
+    }
+    r = read(fd, &x, sizeof(x));
+    if(r == sizeof(x))
+    {
+        return WAIT_OBJECT_0;
+    }
+    if(r == -1 && errno == EAGAIN)
+    {
+        return WAIT_TIMEOUT;
+    }
+    return WAIT_FAILED;
+}
+
+DWORD WaitForMultipleObjects(
+    DWORD        n,
+    const HANDLE *hs,
+    BOOL         bWaitAll,
+    DWORD        dwMilliseconds)
+{
+    if(n == 0)
+    {
+        return bWaitAll ? WAIT_OBJECT_0 : WAIT_FAILED;
+    }
+    DWORD res;
+    int fds[n];
+    int flagss[n];
+    epoll_event evs[n+1]; // +1 for our timer
+    int ufd = -1;
+    int epfd = epoll_create1(EPOLL_CLOEXEC);
+    if(epfd == -1)
+    {
+        goto fail;
+    }
+
+    for(int i = 0; i < n; ++i)
+    {
+        fds[i] = _handleToFD(hs[i]);
+        flagss[i] = _handleToFlags(hs[i]);
+        epoll_event ev;
+        ev.data.fd = fds[i];
+        ev.events = EPOLLIN | EPOLLONESHOT;
+        if(epoll_ctl(epfd, EPOLL_CTL_ADD, fds[i], &ev) == -1)
+        {
+            goto fail;
+        }
+    }
+
+    // The wait all case can't be made correct on linux, as we can't atomically
+    // read from several fds and eventfd is the interface available from
+    // vkd3d-proton.
+    //
+    // As a best-effort we wait until they're all free, then grab them on one
+    // after the other, and put the values back if we can't claim them all, it
+    // sucks.
+    //
+    if(bWaitAll)
+    {
+        // Use a timer to easily know for sure when we've timed out
+        if(dwMilliseconds != INFINITE)
+        {
+            ufd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
+            if(ufd == -1)
+            {
+                goto fail;
+            }
+            itimerspec spec;
+            spec.it_interval.tv_sec = 0;
+            spec.it_interval.tv_nsec = 0;
+            spec.it_value.tv_sec = 0;
+            spec.it_value.tv_nsec = 1000000 * dwMilliseconds;
+            if(timerfd_settime(ufd, 0, &spec, nullptr) == -1)
+            {
+                goto fail;
+            }
+            evs[n].data.fd = ufd;
+            evs[n].events = EPOLLIN | EPOLLONESHOT;
+            if(epoll_ctl(epfd, EPOLL_CTL_ADD, ufd, &evs[n]) == -1)
+            {
+                goto fail;
+            }
+        }
+
+        bool timesUp = false;
+        int nSeenEvents = 0;
+        // Repeatedly call epoll_wait to eliminate read fds until the timer
+        // expires or we have elimininated all our fds
+        do
+        {
+            do
+            {
+                // Wait until epoll tells us they're all available, or the timer is
+                const int nEvents = epoll_wait(epfd, evs, n+1, -1);
+                // We didn't specify a timeout, so 0 results is abnormal
+                if(nEvents < 1)
+                {
+                    goto fail;
+                }
+
+                // Process all the returned fds
+                for(int i = 0; i < nEvents; ++i)
+                {
+                    if(!(evs[i].events & EPOLLIN))
+                    {
+                        // Something exceptional happened on the fd
+                        // Possibly we could just continue and hope it doesn't
+                        // happen again?
+                        goto fail;
+                    }
+                    if(evs[i].data.fd == ufd)
+                    {
+                        // We're out of time, make this the last loop
+                        uint64_t x;
+                        int r = read(ufd, &x, sizeof(x));
+                        if(r == sizeof(x))
+                        {
+                            timesUp = true;
+                        }
+                        else
+                        {
+                            goto fail;
+                        }
+                    }
+                    else
+                    {
+                        // EPOLLONESHOT has removed this fd
+                        ++nSeenEvents;
+                    }
+                }
+            }
+            while(!(timesUp || nSeenEvents == n));
+
+            // If we got here without seeing enough events, we must have timed out
+            if(nSeenEvents < n)
+            {
+                res = WAIT_TIMEOUT;
+                goto end;
+            }
+
+            // See if all the events are readable.
+            // This isn't strictly necessary from a correctness point of view,
+            // but since we're not correct anything we can do helps, and it
+            // makes the code a bit cleaner.
+            // Put all the events back in our epoll instance and see if they're
+            // all readable.
+            for(int i = 0; i < n; ++i)
+            {
+                epoll_event modEv;
+                modEv.data.fd = fds[i];
+                modEv.events = EPOLLIN | EPOLLONESHOT;
+                if(epoll_ctl(epfd, EPOLL_CTL_MOD, fds[i], &modEv) == -1)
+                {
+                    goto fail;
+                }
+            }
+            // Remove the timer if we're using it
+            if(dwMilliseconds != INFINITE && epoll_ctl(epfd, EPOLL_CTL_DEL, ufd, nullptr) == -1)
+            {
+                goto fail;
+            }
+            int nEvents = epoll_wait(epfd, evs, n, 0);
+            if(nEvents < 0)
+            {
+                goto fail;
+            }
+            else if(nEvents < n)
+            {
+                // They're not all still available :(
+                // Put our timer back in and try again from the top
+                if(dwMilliseconds != INFINITE && epoll_ctl(epfd, EPOLL_CTL_ADD, ufd, &evs[n]) == -1)
+                {
+                    goto fail;
+                }
+                // Put back the any fds which did trigger
+                for(int i = 0; i < nEvents; ++i)
+                {
+                    epoll_event modEv = evs[i];
+                    modEv.events = EPOLLIN | EPOLLONESHOT;
+                    if(epoll_ctl(epfd, EPOLL_CTL_MOD, modEv.data.fd, &modEv) == -1)
+                    {
+                        goto fail;
+                    }
+                }
+                continue;
+            }
+            else if(nEvents == n)
+            {
+                for(int i = 0; i < nEvents; ++i)
+                {
+                    if(!(evs->events & EPOLLIN))
+                    {
+                        goto fail;
+                    }
+                }
+            }
+
+            // Try to grab all the events
+            uint64_t vs[n];
+            int i;
+            bool failure = false;
+            for(i = 0; i < n; ++i)
+            {
+                if(flagss[i] & CREATE_EVENT_MANUAL_RESET)
+                {
+                    // We don't need to read this to unset it
+                    continue;
+                }
+                int r = read(fds[i], &vs[i], sizeof(vs[i]));
+                if(r == sizeof(vs[i]))
+                {
+                    continue;
+                }
+                else if(r == -1 && errno == EAGAIN)
+                {
+                    // contention, put things back and try again
+                    break;
+                }
+                else
+                {
+                    // failure, put things back and fail
+                    failure = true;
+                    break;
+                }
+            }
+            if (i < n)
+            {
+                // contention or failure
+                for(int j = 0; j < i; ++j)
+                {
+                    if(flagss[i] & CREATE_EVENT_MANUAL_RESET)
+                    {
+                        // We didn't read, so we shouldn't write
+                        continue;
+                    }
+                    // TODO: If this doesn't succeed then another thread has jumped
+                    // in between our non-atomic reads earlier, oops!
+                    //
+                    // This is just one case of failure we can detect,
+                    // arbitrarily many things may have happened between reads
+                    // and we just wouldn't know...
+                    int w = write(fds[j], &vs[j], sizeof(vs[j]));
+                    SLANG_ASSERT(w == sizeof(vs[j]));
+                }
+                if(failure)
+                {
+                    goto fail;
+                }
+            }
+            else
+            {
+                // success
+                res = WAIT_OBJECT_0;
+                goto end;
+            }
+
+            // If we get here then we've got some contention, go back to the top and try again (or timeout)
+        }
+        while(!timesUp);
+    }
+    else
+    {
+        // Wait any
+        const int nEvents = epoll_wait(epfd, evs, n, dwMilliseconds == INFINITE ? -1 : dwMilliseconds);
+        if(nEvents == -1)
+        {
+            goto fail;
+        }
+        if(nEvents == 0)
+        {
+            res = WAIT_TIMEOUT;
+            goto end;
+        }
+        // Try reads until we get one
+        for(int i = 0; i < nEvents; ++i)
+        {
+            uint64_t x;
+            if(!evs[i].events & EPOLLIN)
+            {
+                continue;
+            }
+            const int r = ::read(evs[i].data.fd, &x, sizeof(x));
+            if (r == sizeof(x))
+            {
+                res = WAIT_OBJECT_0;
+                goto end;
+            }
+            if (errno != EAGAIN)
+            {
+                goto fail;
+            }
+            // Some other waiter got this one first
+        }
+    }
+
+    goto end;
+fail:
+    res = WAIT_FAILED;
+end:
+    close(ufd);
+    close(epfd);
+    return res;
+}
+
+#endif // SLANG_LINUX_FAMILY
diff --git a/tools/gfx/d3d12/d3d12-posix-synchapi.h b/tools/gfx/d3d12/d3d12-posix-synchapi.h
new file mode 100644
index 000000000..fb556fb51
--- /dev/null
+++ b/tools/gfx/d3d12/d3d12-posix-synchapi.h
@@ -0,0 +1,66 @@
+#pragma once
+
+#include "slang.h"
+
+#if SLANG_LINUX_FAMILY
+
+#pragma push_macro("WIN32_LEAN_AND_MEAN")
+#pragma push_macro("NOMINMAX")
+#undef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#undef NOMINMAX
+#define NOMINMAX
+#include <windows.h>
+#pragma pop_macro("NOMINMAX")
+#pragma pop_macro("WIN32_LEAN_AND_MEAN")
+
+////////////////////////////////////////////////////////////////
+//
+// It's important to note that due to platform constraints this can't be a
+// totally faithful implementation of the Windows API.
+//
+// Notably, the "wait all" case in WaitForMultipleObjects can't be made correct
+// on linux, as we can't atomically read from several fds and eventfd is the
+// interface available from vkd3d-proton.
+//
+////////////////////////////////////////////////////////////////
+
+//
+// The synchapi types and macros used in gfx
+//
+#define INFINITE 0xffffffff
+
+#define WAIT_FAILED 0xffffffff
+#define WAIT_OBJECT_0 0
+#define WAIT_TIMEOUT 258
+
+typedef struct _SECURITY_ATTRIBUTES *LPSECURITY_ATTRIBUTES;
+
+#define CREATE_EVENT_MANUAL_RESET 1
+#define CREATE_EVENT_INITIAL_SET  2
+
+#define SYNCHRONIZE               0x00100000
+#define STANDARD_RIGHTS_REQUIRED  0x000f0000
+#define EVENT_ALL_ACCESS          (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0x3)
+
+HANDLE CreateEventEx(
+    LPSECURITY_ATTRIBUTES lpEventAttributes,
+    LPCSTR                lpName,
+    DWORD                 dwFlags,
+    DWORD                 dwDesiredAccess);
+
+BOOL CloseHandle(HANDLE h);
+
+BOOL ResetEvent(HANDLE h);
+
+BOOL SetEvent(HANDLE h);
+
+DWORD WaitForSingleObject(HANDLE h, DWORD ms);
+
+DWORD WaitForMultipleObjects(
+    DWORD        nHandles,
+    const HANDLE *handles,
+    BOOL         bWaitAll,
+    DWORD        dwMilliseconds);
+
+#endif // SLANG_LINUX_FAMILY
diff --git a/tools/gfx/d3d12/d3d12-texture.cpp b/tools/gfx/d3d12/d3d12-texture.cpp
index 4f1898ef7..9f47760e5 100644
--- a/tools/gfx/d3d12/d3d12-texture.cpp
+++ b/tools/gfx/d3d12/d3d12-texture.cpp
@@ -30,6 +30,9 @@ Result TextureResourceImpl::getNativeResourceHandle(InteropHandle* outHandle)
 
 Result TextureResourceImpl::getSharedHandle(InteropHandle* outHandle)
 {
+#if !SLANG_WINDOWS_FAMILY
+    return SLANG_E_NOT_IMPLEMENTED;
+#else
     // Check if a shared handle already exists for this resource.
     if (sharedHandle.handleValue != 0)
     {
@@ -45,6 +48,7 @@ Result TextureResourceImpl::getSharedHandle(InteropHandle* outHandle)
         pResource, NULL, GENERIC_ALL, nullptr, (HANDLE*)&outHandle->handleValue));
     outHandle->api = InteropHandleAPI::D3D12;
     return SLANG_OK;
+#endif
 }
 
 Result TextureResourceImpl::setDebugName(const char* name)