Feature/shared library refactor (#712)

* * Added ISlangSharedLibraryLoader and ISlangSharedLibrary
* Implemented default implementations
* Added slang API function to get/set the ISlangSharedLibraryLoader on the session
* Put function caching onto the Session - so that if the loader is chaged, its easy to reset the shared libraries, and functions

* Run premake.

* Fix problem with setting null, would cause an unnecessary function/shared lib flush.

* * Unload SharedLibrary when DefaultSharedLibrary is deleted.
* Make SharedLibrary handle unload safely if already unloaded.

* Refactor SharedLibrary, such that it becomes a utility class - simplifying it's semantics.

* Simplified ISlangSharedLibrary such that doesn't have unload and isLoaded so easier to implement.
Use updated SharedLibrary impl.

* Disable aarch64 on windows

* Premake windows files without aarch64 build.

* Moved slang-shared-library to core (so can be used in code outside of main slang)
Fixed problem in premake5 where on windows projects were incorrectly constructed

* Allowed RefObject to base class of com types
Added ConfigurableSharedLibraryLoader
Added -dxc-path -fxc-path -glslang-path
Fix problem with dxc-path not honoring it's path when loading dxil

* Added documentation for command line control of dll loading paths.

* Remove some tabbing issues.

* Change name of include guard.

1 files changed, 115 insertions, 0 deletions

diff --git a/source/core/slang-shared-library.cpp b/source/core/slang-shared-library.cpp
new file mode 100644
index 000000000..716f570c4
--- /dev/null
+++ b/source/core/slang-shared-library.cpp
@@ -0,0 +1,115 @@
+#include "slang-shared-library.h"
+
+#include "../../slang-com-ptr.h"
+#include "../core/slang-io.h"
+#include "../core/slang-string-util.h"
+
+namespace Slang
+{
+
+// Allocate static const storage for the various interface IDs that the Slang API needs to expose
+static const Guid IID_ISlangUnknown = SLANG_UUID_ISlangUnknown;
+static const Guid IID_ISlangSharedLibrary = SLANG_UUID_ISlangSharedLibrary;
+static const Guid IID_ISlangSharedLibraryLoader = SLANG_UUID_ISlangSharedLibraryLoader;
+
+/* !!!!!!!!!!!!!!!!!!!!!!!!!! DefaultSharedLibraryLoader !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*/
+
+/* static */const char* DefaultSharedLibraryLoader::s_libraryNames[int(SharedLibraryType::CountOf)] =
+{
+    nullptr,                    // SharedLibraryType::Unknown 
+    "dxcompiler",               // SharedLibraryType::Dxc 
+    "d3dcompiler_47",           // SharedLibraryType::Fxc
+    "slang-glslang",            // SharedLibraryType::Glslang  
+    "dxil",                     // SharedLibraryType::Dxil
+};
+
+/* static */DefaultSharedLibraryLoader DefaultSharedLibraryLoader::s_singleton;
+
+/* static */SharedLibraryType DefaultSharedLibraryLoader::getSharedLibraryTypeFromName(const UnownedStringSlice& name)
+{
+    // Start from 1 to skip Unknown
+    for (int i = 1; i < SLANG_COUNT_OF(s_libraryNames); ++i)
+    {
+        if (name == s_libraryNames[i])
+        {
+            return SharedLibraryType(i);
+        }
+    }
+    return SharedLibraryType::Unknown;
+}
+
+ISlangUnknown* DefaultSharedLibraryLoader::getInterface(const Guid& guid)
+{
+    return (guid == IID_ISlangUnknown || guid == IID_ISlangSharedLibraryLoader) ? static_cast<ISlangSharedLibraryLoader*>(this) : nullptr;
+}
+
+SlangResult DefaultSharedLibraryLoader::loadSharedLibrary(const char* path, ISlangSharedLibrary** sharedLibraryOut)
+{
+    *sharedLibraryOut = nullptr;
+    // Try loading
+    SharedLibrary::Handle handle;
+    SLANG_RETURN_ON_FAIL(SharedLibrary::load(path, handle));
+    *sharedLibraryOut = ComPtr<ISlangSharedLibrary>(new DefaultSharedLibrary(handle)).detach();
+    return SLANG_OK;
+}
+
+/* !!!!!!!!!!!!!!!!!!!!!!!!!! DefaultSharedLibrary !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*/
+
+ISlangUnknown* DefaultSharedLibrary::getInterface(const Guid& guid)
+{
+    return (guid == IID_ISlangUnknown || guid == IID_ISlangSharedLibrary) ? static_cast<ISlangSharedLibrary*>(this) : nullptr;
+}
+
+DefaultSharedLibrary::~DefaultSharedLibrary()
+{
+    SharedLibrary::unload(m_sharedLibraryHandle);
+}
+
+SlangFuncPtr DefaultSharedLibrary::findFuncByName(char const* name)
+{
+    return SharedLibrary::findFuncByName(m_sharedLibraryHandle, name); 
+}
+
+/* !!!!!!!!!!!!!!!!!!!!!!!!!! ConfigurableSharedLibraryLoader !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*/
+
+ISlangUnknown* ConfigurableSharedLibraryLoader::getInterface(const Guid& guid)
+{
+    return (guid == IID_ISlangUnknown || guid == IID_ISlangSharedLibraryLoader) ? static_cast<ISlangSharedLibraryLoader*>(this) : nullptr;
+}
+
+SlangResult ConfigurableSharedLibraryLoader::loadSharedLibrary(const char* path, ISlangSharedLibrary** sharedLibraryOut)
+{
+    Entry* entry = m_entryMap.TryGetValue(String(path));
+    if (entry)
+    {
+        SharedLibrary::Handle handle;
+        SLANG_RETURN_ON_FAIL(entry->func(path, entry->entryString, handle));
+        SLANG_ASSERT(handle);
+
+        ComPtr<ISlangSharedLibrary> sharedLib(new DefaultSharedLibrary(handle));
+        *sharedLibraryOut = sharedLib.detach();
+        return SLANG_OK;
+    }
+
+    return DefaultSharedLibraryLoader::getSingleton()->loadSharedLibrary(path, sharedLibraryOut);
+}
+
+/* static */Result ConfigurableSharedLibraryLoader::replace(const char* pathIn, const String& entryString, SharedLibrary::Handle& handleOut)
+{
+    SLANG_UNUSED(pathIn);
+    // The replacement is the *whole* string
+    return SharedLibrary::loadWithPlatformFilename(entryString.begin(), handleOut);
+}
+
+/* static */Result ConfigurableSharedLibraryLoader::changePath(const char* pathIn, const String& entryString, SharedLibrary::Handle& handleOut )
+{
+    // Okay we need to reconstruct the name and insert the path
+    StringBuilder builder;
+    SharedLibrary::appendPlatformFileName(UnownedStringSlice(pathIn), builder);
+    String path = Path::Combine(entryString, builder);
+
+    return SharedLibrary::loadWithPlatformFilename(path.begin(), handleOut);
+}
+
+
+} 
\ No newline at end of file