Ability to set Paths on Pass Through/Back End Compilers (#1010)

* Expanded prelude for some other resource types. Disable C++ output for ParameterGroup.

* WIP: Layout for CPU.

* Fixes to CPU layout.

* WIP: The uniform is output, but the variable definition is not.

* WIP: Entry point parameters to global scope in C++.
Handling of resource types (in so far as outputting)

* Some discussion of ABI and different input types.

* WIP: More C++ support around resource types.

* WIP: Split up variables into different structures on emit.

* WIP: Emitting C++ with wrapping up of 'Context'

* WIP: C++ code has access to semantic values.
Wrap in struct so can use method calls to pass shared state.
Disable  legalizeResourceTypes and legalizeExistentialTypeLayout

* Fix structured buffer layout for CPU.

* Remove testing/handling of global uniforms on CPU path.
Typo fix.
Changed CPU tests to use new CPU calling convention.

* Check globals are working. Initalize context to zero globals.

* Order the global parameters for C++ ouput by their layout.
Note - that layout isn't quite working correctly because the StructuredBuffer<int> the int seems to be consuming uniform space.

* Work around for reflection not having all data needed for layout ordering for C++ code.

* Output constant buffers as pointers.

* Entry point parameters accessed through pointer to struct.

* WIP: Layout for CPU is reasonable for test case.

* Only output 'f' after float literal if type marks as a float.

* Cast construction works on C++.

* Made IntrinsicOp::ConvertConstruct to make intent clearer.

* C++ handling construction from scalar.
Handle access of a scalar with .x.
Check default initialization.

* Comment about need for split of kIROp_construct.
Release build works.

* Added support from constructVectorFromScalar to C/C++ target.

* Handling of in/out in C/C++.

* First pass documentation CPU support.

* Improvements to C++/C slang code generation documentation.

* Small doc change to include need for mechansim to specify cpp compiler path.

* WIP: Being able to set path for backends.

* Better handling of swizzling - allow swizzling a scalar into a vector.

* Fix missing/broken headers for path setting on session.

* Fix for compiling using clang on Windows.

* Remove Clang test code.

* * Removed spSessionGetGlobalSession - no longer needed because SlangSession is slang::IGlobalSession alias.
* Gave Session a ref count on spCreateSession, and have it checked on spDestroySession, so behaves correctly as ISlangUnknown

Note that spDestroySession does a release (and checks the ref count on debug builds). It's behaviour could be the same as just release, but this seems closer to the original intention.

1 files changed, 57 insertions, 4 deletions

diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index bb7e705e6..f0570132f 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -146,6 +146,51 @@ SLANG_NO_THROW SlangProfileID SLANG_MCALL Session::findProfile(
     return Slang::Profile::LookUp(name).raw;
 }
 
+SLANG_NO_THROW void SLANG_MCALL Session::setPassThroughPath(
+    SlangPassThrough inPassThrough,
+    char const* path)
+{
+    PassThroughMode passThrough = PassThroughMode(inPassThrough);
+    SLANG_ASSERT(int(passThrough) > int(PassThroughMode::None) && int(passThrough) < int(PassThroughMode::CountOf));
+    
+    if (m_passThroughPaths[int(passThrough)] != path)
+    {
+        // If it's changed we should unload any shared libraries that use it
+        switch (passThrough)
+        {
+            case PassThroughMode::Dxc:
+            {
+                setSharedLibrary(SharedLibraryType::Dxc, nullptr);
+                setSharedLibrary(SharedLibraryType::Dxil, nullptr);
+                break;
+            }
+            case PassThroughMode::Fxc:
+            {
+                setSharedLibrary(SharedLibraryType::Fxc, nullptr);
+                break;
+            }
+            case PassThroughMode::Glslang:
+            {
+                setSharedLibrary(SharedLibraryType::Glslang, nullptr);
+                break;
+            }
+            case PassThroughMode::VisualStudio:
+            case PassThroughMode::Gcc:
+            case PassThroughMode::Clang:
+            case PassThroughMode::GenericCCpp:
+            {
+                // If any compiler path set changed, require all to be refreshed
+                cppCompilerSet.setNull();
+                break;
+            }
+            default: break;
+        }
+
+        // Set the path
+        m_passThroughPaths[int(passThrough)] = path;
+    }
+}
+
 struct IncludeHandlerImpl : IncludeHandler
 {
     Linkage*    linkage;
@@ -2446,7 +2491,9 @@ Session::~Session()
 
 SLANG_API SlangSession* spCreateSession(const char*)
 {
-    return asExternal(new Slang::Session());
+    Slang::RefPtr<Slang::Session> session(new Slang::Session());
+    // Will be returned with a refcount of 1
+    return asExternal(session.detach());
 }
 
 SLANG_API SlangResult slang_createGlobalSession(
@@ -2463,10 +2510,16 @@ SLANG_API SlangResult slang_createGlobalSession(
 }
 
 SLANG_API void spDestroySession(
-    SlangSession*   session)
+    SlangSession*   inSession)
 {
-    if(!session) return;
-    delete Slang::asInternal(session);
+    if(!inSession) return;
+
+    Slang::Session* session = Slang::asInternal(inSession);
+    // It is assumed there is only a single reference on the session (the one placed
+    // with spCreateSession) if this function is called
+    SLANG_ASSERT(session->debugGetReferenceCount() == 1);
+    // Release
+    session->release();
 }
 
 SLANG_API void spAddBuiltins(