Add a CPU renderer implementation (#1750)

* Add a CPU renderer implementation

This change adds a CPU back-end to `gfx` and ensures that most of our existing CPU tests pass when using it.

Detailed notes:

* Most of the CPU renderer implementation is copy-pasted from the CUDA case, so they share a lot of similar logic

* The main addition to the CPU renderer is a semi-complete implementation of host-memory textures. The logic here handles all the main shapes (Buffer, 1D, 2D, 3D, Cube) and all the currently-supported `Format`s that are sample-able as-is (no D24S8). The implementation is not intended to be fast, and it currently only does nearest-neighbor sampling, but otherwise it tries to avoid cutting too many corners and should be ar reasonable starting point for a more complete (but not performance-oriented) implementation.

* Refactored the CPU prelude `IRWTexture` interface to inherit from `ITexture`, since in most cases a single type will end up implementing both. It might be worth it to collapse it all down to a single interface later.

* Changed the CPU prelude `ITexture`/`IRWTexture` interface so that it takes both a pointer *and* a size for output arguments. This change seems necessary to allow a shader variable declared as a `Texture2D<float>` to fetch a single `float` when the underlying texture might be using RGBA32F.

* Added to the `IComponentType` public API so that we can query a "host callable" for an entry point and not just a binary.

* Turned off the `-shaderobj` flag on two tests that weren't yet compatible with shader objects but still had the flag left in on the path (since previously the CPU path always used the non-`gfx` non-shader-object logic anyway)

* Disabled one test (`dynamic-dispatch-11`) that relied on the `ConstantBuffer<IInterface>` idiom that we know we are planning to chagne soon anyway.

* Made a few changes to the CUDA path to bring it into line with what I added for the CPU path. These were mostly bug fixes around indexing logic for sub-objects and resources.

* fixup

1 files changed, 31 insertions, 1 deletions

diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index 2ad5d25f8..ae3a1f419 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -2733,6 +2733,33 @@ SLANG_NO_THROW SlangResult SLANG_MCALL ComponentType::getEntryPointCode(
     return SLANG_OK;
 }
 
+SLANG_NO_THROW SlangResult SLANG_MCALL ComponentType::getEntryPointHostCallable(
+    int                     entryPointIndex,
+    int                     targetIndex,
+    ISlangSharedLibrary**   outSharedLibrary,
+    slang::IBlob**          outDiagnostics)
+{
+    auto linkage = getLinkage();
+    if(targetIndex < 0 || targetIndex >= linkage->targets.getCount())
+        return SLANG_E_INVALID_ARG;
+    auto target = linkage->targets[targetIndex];
+
+    auto targetProgram = getTargetProgram(target);
+
+    DiagnosticSink sink(linkage->getSourceManager(), Lexer::sourceLocationLexer);
+    auto& entryPointResult = targetProgram->getOrCreateEntryPointResult(entryPointIndex, &sink);
+    sink.getBlobIfNeeded(outDiagnostics);
+
+    if(entryPointResult.format == ResultFormat::None )
+        return SLANG_FAIL;
+
+    ComPtr<ISlangSharedLibrary> sharedLibrary;
+    SLANG_RETURN_ON_FAIL(entryPointResult.getSharedLibrary(sharedLibrary));
+
+    *outSharedLibrary = sharedLibrary.detach();
+    return SLANG_OK;
+}
+
 RefPtr<ComponentType> ComponentType::specialize(
     SpecializationArg const*    inSpecializationArgs,
     SlangInt                    specializationArgCount,
@@ -4385,7 +4412,10 @@ SlangReflection* EndToEndCompileRequest::getReflection()
 
     auto targetReq = linkage->targets[targetIndex];
     auto targetProgram = program->getTargetProgram(targetReq);
-    auto programLayout = targetProgram->getExistingLayout();
+
+
+    DiagnosticSink sink(linkage->getSourceManager(), Lexer::sourceLocationLexer);
+    auto programLayout = targetProgram->getOrCreateLayout(&sink);
 
     return (SlangReflection*)programLayout;
 }