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, 26 insertions, 3 deletions

diff --git a/source/slang/compiler.h b/source/slang/compiler.h
index 1f4a4736a..c8c242568 100644
--- a/source/slang/compiler.h
+++ b/source/slang/compiler.h
@@ -1,7 +1,9 @@
-#ifndef RASTER_SHADER_COMPILER_H
-#define RASTER_SHADER_COMPILER_H
+#ifndef SLANG_COMPILER_H_INCLUDED
+#define SLANG_COMPILER_H_INCLUDED
 
 #include "../core/basic.h"
+#include "../core/slang-shared-library.h"
+
 #include "../../slang-com-ptr.h"
 
 #include "diagnostics.h"
@@ -77,7 +79,7 @@ namespace Slang
 
     // When storing the layout for a matrix-type
     // value, we need to know whether it has been
-    // laid ot with row-major or column-major
+    // laid out with row-major or column-major
     // storage.
     //
     enum MatrixLayoutMode
@@ -503,6 +505,15 @@ namespace Slang
     class Session
     {
     public:
+        enum class SharedLibraryFuncType
+        {
+            Glslang_Compile,
+            Fxc_D3DCompile,
+            Fxc_D3DDisassemble,
+            Dxc_DxcCreateInstance,
+            CountOf,
+        };
+
         //
 
         RefPtr<Scope>   baseLanguageScope;
@@ -544,6 +555,10 @@ namespace Slang
         RefPtr<Type> constExprRate;
         RefPtr<Type> irBasicBlockType;
 
+        ComPtr<ISlangSharedLibraryLoader> sharedLibraryLoader;                          ///< The shared library loader (never null)
+        ComPtr<ISlangSharedLibrary> sharedLibraries[int(SharedLibraryType::CountOf)];   ///< The loaded shared libraries
+        SlangFuncPtr sharedLibraryFunctions[int(SharedLibraryFuncType::CountOf)];
+
         Dictionary<int, RefPtr<Type>> builtinTypes;
         Dictionary<String, Decl*> magicDecls;
 
@@ -602,6 +617,14 @@ namespace Slang
         void destroyTypeCheckingCache();
         //
 
+            /// Will try to load the library by specified name (using the set loader), if not one already available.
+        ISlangSharedLibrary* getOrLoadSharedLibrary(SharedLibraryType type, DiagnosticSink* sink);
+
+            /// Gets a shared library by type, or null if not loaded
+        ISlangSharedLibrary* getSharedLibrary(SharedLibraryType type) const { return sharedLibraries[int(type)]; }
+
+        SlangFuncPtr getSharedLibraryFunc(SharedLibraryFuncType type, DiagnosticSink* sink);
+
         Session();
 
         void addBuiltinSource(