Bring heterogeneous-hello-world back up to date. (#1935)

* Bring heterogeneous-hello-world back up to date.

* Reintroduced heterogeneous-hello-world into the premake

* No longer uses compiled bytecode for entry point, instead a loadModule
call is hardocoded with the slang file name.

* Entry point is, similarly, hardcoded for now.

* Added a bypass to slang-legalize-types for an unneeded GPUForeach check

* Run premake and change to relative path

* Removed experimental and added README

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 335 insertions, 0 deletions

diff --git a/examples/heterogeneous-hello-world/main.cpp b/examples/heterogeneous-hello-world/main.cpp
new file mode 100644
index 000000000..9e0bb8b0f
--- /dev/null
+++ b/examples/heterogeneous-hello-world/main.cpp
@@ -0,0 +1,335 @@
+// main.cpp
+
+// This example uses the Slang gfx layer to target different APIs and execute
+// both CPU and GPU code from a single Slang file (?)
+//
+#include <slang.h>
+#include <slang-com-ptr.h>
+using Slang::ComPtr;
+
+#include "slang-gfx.h"
+#include "gfx-util/shader-cursor.h"
+#include "source/core/slang-basic.h"
+#include "../../prelude/slang-cpp-types.h"
+
+using namespace gfx;
+using namespace Slang;
+
+// Creating global ref pointers to avoid dereferencing values
+//
+ComPtr<gfx::IDevice> gDevice;
+ComPtr<gfx::IShaderProgram> gProgram;
+ComPtr<gfx::IBufferResource> gBufferResource;
+ComPtr<gfx::IResourceView> gResourceView;
+ComPtr<gfx::ITransientResourceHeap> gTransientHeap;
+ComPtr<gfx::IPipelineState> gPipelineState;
+ComPtr<gfx::ICommandQueue> gQueue;
+
+// Boilerplate types to help the slang-generated file
+//
+struct gfx_Device_0;
+struct gfx_BufferResource_0;
+struct gfx_ShaderProgram_0;
+struct gfx_ResourceView_0;
+struct gfx_TransientResourceHeap_0;
+struct gfx_PipelineState_0;
+bool executeComputation_0();
+
+// Many Slang API functions return detailed diagnostic information
+// (error messages, warnings, etc.) as a "blob" of data, or return
+// a null blob pointer instead if there were no issues.
+//
+// For convenience, we define a subroutine that will dump the information
+// in a diagnostic blob if one is produced, and skip it otherwise.
+//
+void diagnoseIfNeeded(slang::IBlob *diagnosticsBlob)
+{
+    if (diagnosticsBlob != nullptr)
+    {
+        printf("%s", (const char *)diagnosticsBlob->getBufferPointer());
+    }
+}
+
+gfx::IDevice* createDevice()
+{
+    ComPtr<gfx::IDevice> device;
+    IDevice::Desc deviceDesc = {};
+    // Changing device type would happen here. For example:
+    //deviceDesc.deviceType = DeviceType::CUDA;
+    SLANG_RETURN_NULL_ON_FAIL(gfxCreateDevice(&deviceDesc, gDevice.writeRef()));
+    return gDevice;
+}
+
+// Loads the shader code defined in `shader.slang` for use by the `gfx` layer.
+//
+gfx::IShaderProgram* loadShaderProgram(gfx::IDevice *device)
+{
+    // We need to obtain a compilation session (`slang::ISession`) that will provide
+    // a scope to all the compilation and loading of code we do.
+    //
+    ComPtr<slang::ISession> slangSession;
+    SLANG_RETURN_NULL_ON_FAIL(device->getSlangSession(slangSession.writeRef()));
+
+    // We can now start loading code into the slang session.
+    //
+    // The simplest way to load code is by calling `loadModule` with the name of a Slang
+    // module. A call to `loadModule("MyStuff")` will behave more or less as if you
+    // wrote:
+    //
+    //      import MyStuff;
+    //
+    // In a Slang shader file. The compiler will use its search paths to try to locate
+    // `MyModule.slang`, then compile and load that file. If a matching module had
+    // already been loaded previously, that would be used directly.
+    //
+    ComPtr<slang::IBlob> diagnosticsBlob;
+    slang::IModule *module = slangSession->loadModule("shader", diagnosticsBlob.writeRef());
+    diagnoseIfNeeded(diagnosticsBlob);
+    if (!module)
+        return NULL;
+
+    // Look up entry point (hardcoded for now)
+    //
+    char const *computeEntryPointName = "computeMain";
+    ComPtr<slang::IEntryPoint> computeEntryPoint;
+    SLANG_RETURN_NULL_ON_FAIL(
+        module->findEntryPointByName(computeEntryPointName, computeEntryPoint.writeRef()));
+
+    // At this point we have a few different Slang API objects that represent
+    // pieces of our code: `module`, `vertexEntryPoint`, and `fragmentEntryPoint`.
+    //
+    // A single Slang module could contain many different entry points (e.g.,
+    // four vertex entry points, three fragment entry points, and two compute
+    // shaders), and before we try to generate output code for our target API
+    // we need to identify which entry points we plan to use together.
+    //
+    // Modules and entry points are both examples of *component types* in the
+    // Slang API. The API also provides a way to build a *composite* out of
+    // other pieces, and that is what we are going to do with our module
+    // and entry points.
+    //
+    Slang::List<slang::IComponentType *> componentTypes;
+    componentTypes.add(module);
+    componentTypes.add(computeEntryPoint);
+
+    // Actually creating the composite component type is a single operation
+    // on the Slang session, but the operation could potentially fail if
+    // something about the composite was invalid (e.g., you are trying to
+    // combine multiple copies of the same module), so we need to deal
+    // with the possibility of diagnostic output.
+    //
+    ComPtr<slang::IComponentType> composedProgram;
+    SlangResult result = slangSession->createCompositeComponentType(
+        componentTypes.getBuffer(),
+        componentTypes.getCount(),
+        composedProgram.writeRef(),
+        diagnosticsBlob.writeRef());
+    diagnoseIfNeeded(diagnosticsBlob);
+    SLANG_RETURN_NULL_ON_FAIL(result);
+
+    // At this point, `composedProgram` represents the shader program
+    // we want to run, and the compute shader there have been checked.
+    // We can create a `gfx::IShaderProgram` object from `composedProgram`
+    // so it may be used by the graphics layer.
+    gfx::IShaderProgram::Desc programDesc = {};
+    programDesc.pipelineType = gfx::PipelineType::Compute;
+    programDesc.slangProgram = composedProgram.get();
+
+    gProgram = device->createProgram(programDesc);
+
+    return gProgram;
+}
+
+gfx::IBufferResource* createStructuredBuffer(
+    gfx::IDevice *device,
+    float *initialData)
+{
+    // Create a structured buffer for storing computation data
+    //
+    const int numberCount = 4;
+    int structuredBufferSize = numberCount * sizeof(float);
+
+    IBufferResource::Desc bufferDesc = {};
+    bufferDesc.sizeInBytes = numberCount * sizeof(float);
+    bufferDesc.format = gfx::Format::Unknown;
+    bufferDesc.elementSize = sizeof(float);
+    bufferDesc.allowedStates = ResourceStateSet(ResourceState::ShaderResource,
+                                                ResourceState::UnorderedAccess,
+                                                ResourceState::CopyDestination,
+                                                ResourceState::CopySource);
+    bufferDesc.defaultState = ResourceState::UnorderedAccess;
+    bufferDesc.cpuAccessFlags = AccessFlag::Write | AccessFlag::Read;
+
+    SlangResult result = device->createBufferResource(bufferDesc,
+                                                      (void *)initialData,
+                                                      gBufferResource.writeRef());
+    SLANG_RETURN_NULL_ON_FAIL(result);
+    return gBufferResource;
+}
+
+gfx::IResourceView* createBufferView(
+    gfx::IDevice* device,
+    gfx::IBufferResource* buffer)
+{
+    // Create a resource view for the structured buffer
+    //
+    gfx::IResourceView::Desc viewDesc = {};
+    viewDesc.type = gfx::IResourceView::Type::UnorderedAccess;
+    viewDesc.format = gfx::Format::Unknown;
+    SLANG_RETURN_NULL_ON_FAIL(device->createBufferView(buffer, viewDesc, gResourceView.writeRef()));
+    return gResourceView;
+}
+
+gfx::ITransientResourceHeap* buildTransientHeap(gfx::IDevice *device)
+{
+    ITransientResourceHeap::Desc transientHeapDesc = {};
+    transientHeapDesc.constantBufferSize = 4096;
+    SLANG_RETURN_NULL_ON_FAIL(
+        device->createTransientResourceHeap(transientHeapDesc, gTransientHeap.writeRef()));
+    return gTransientHeap;
+}
+
+gfx::IPipelineState* buildPipelineState(
+    gfx::IDevice *device,
+    gfx::IShaderProgram* shaderProgram)
+{
+    gfx::ComputePipelineStateDesc pipelineDesc = {};
+    pipelineDesc.program = shaderProgram;
+    SLANG_RETURN_NULL_ON_FAIL(
+        device->createComputePipelineState(pipelineDesc, gPipelineState.writeRef()));
+    return gPipelineState;
+}
+
+void printInitialValues(float *initialArray, int length)
+{
+    printf("Before:\n");
+    for (int i = 0; i < length; i++)
+    {
+        printf("%f, ", initialArray[i]);
+    }
+    printf("\n");
+}
+
+void dispatchComputation(
+    gfx::IDevice* device,
+    gfx::ITransientResourceHeap* transientHeap,
+    gfx::IPipelineState* pipelineState,
+    gfx::IResourceView* bufferView,
+    unsigned int gridDimsX,
+    unsigned int gridDimsY,
+    unsigned int gridDimsZ)
+{
+    ICommandQueue::Desc queueDesc = {ICommandQueue::QueueType::Graphics};
+    gQueue = device->createCommandQueue(queueDesc);
+
+    auto commandBuffer = transientHeap->createCommandBuffer();
+    auto encoder = commandBuffer->encodeComputeCommands();
+
+    // First, obtain a root shader object from command encoder to start parameter binding.
+    auto rootObject = encoder->bindPipeline(pipelineState);
+
+    gfx::ShaderCursor entryPointCursor(
+        rootObject->getEntryPoint(0)); // get a cursor the the first entry-point.
+    // Bind buffer view to the entry point.
+    entryPointCursor.getPath("ioBuffer").setResource(bufferView);
+
+    encoder->dispatchCompute(gridDimsX, gridDimsY, gridDimsZ);
+    encoder->endEncoding();
+    commandBuffer->close();
+    gQueue->executeCommandBuffer(commandBuffer);
+    gQueue->wait();
+}
+
+bool printOutputValues(
+    gfx::IDevice *device,
+    gfx::IBufferResource *buffer,
+    int length)
+{
+    ComPtr<ISlangBlob> resultBlob;
+    SLANG_RETURN_FALSE_ON_FAIL(device->readBufferResource(
+        buffer, 0, length * sizeof(float), resultBlob.writeRef()));
+    auto result = reinterpret_cast<const float *>(resultBlob->getBufferPointer());
+    printf("After: \n");
+    for (int i = 0; i < length; i++)
+    {
+        printf("%f, ", result[i]);
+    }
+    printf("\n");
+    return true;
+}
+
+// Boilerplate functions to help the slang-generated file and types
+
+gfx_Device_0* createDevice_0()
+{
+     return (gfx_Device_0*)createDevice();
+}
+
+gfx_BufferResource_0* createStructuredBuffer_0(gfx_Device_0* _0, FixedArray<float, 4> _1)
+{
+    return (gfx_BufferResource_0*)createStructuredBuffer((gfx::IDevice*)_0, (float*)&_1);
+}
+
+gfx_ShaderProgram_0* loadShaderProgram_0(gfx_Device_0* _0)
+{
+    return (gfx_ShaderProgram_0*)loadShaderProgram((gfx::IDevice*)_0);
+}
+
+gfx_ResourceView_0* createBufferView_0(gfx_Device_0* _0, gfx_BufferResource_0* _1)
+{
+    return (gfx_ResourceView_0*)createBufferView((gfx::IDevice*)_0, (gfx::IBufferResource*)_1);
+}
+
+gfx_TransientResourceHeap_0* buildTransientHeap_0(gfx_Device_0* _0)
+{
+    return (gfx_TransientResourceHeap_0*)buildTransientHeap((gfx::IDevice*)_0);
+}
+
+gfx_PipelineState_0* buildPipelineState_0(gfx_Device_0* _0, gfx_ShaderProgram_0* _1)
+{
+    return (gfx_PipelineState_0*)buildPipelineState((gfx::IDevice*)_0, (gfx::IShaderProgram*)_1);
+}
+
+void printInitialValues_0(FixedArray<float, 4> _0, int32_t _1)
+{
+    printInitialValues((float*)&_0, _1);
+}
+
+void dispatchComputation_0(gfx_Device_0* _0, gfx_TransientResourceHeap_0* _1, gfx_PipelineState_0* _2, gfx_ResourceView_0* _3, unsigned int gridDimsX, unsigned int gridDimsY, unsigned int gridDimsZ)
+{
+    dispatchComputation(
+        (gfx::IDevice*)_0,
+        (gfx::ITransientResourceHeap*)_1,
+        (gfx::IPipelineState*)_2,
+        (gfx::IResourceView*)_3,
+        gridDimsX,
+        gridDimsY,
+        gridDimsZ);
+}
+
+RWStructuredBuffer<float> convertBuffer_0(gfx_BufferResource_0* _0) {
+    RWStructuredBuffer<float> result;
+    result.data = (float*)_0;
+    return result;
+}
+
+gfx_BufferResource_0* unconvertBuffer_0(RWStructuredBuffer<float> _0) {
+    return (gfx_BufferResource_0*)(_0.data);
+}
+
+bool printOutputValues_0(gfx_Device_0* _0, gfx_BufferResource_0* _1, int32_t _2)
+{
+    return printOutputValues((gfx::IDevice*)_0, (gfx::IBufferResource*)_1, _2);
+}
+
+int main()
+{
+    // We construct an instance of our example application
+    // `struct` type, and then walk through the lifecyle
+    // of the application.
+
+    if (!(executeComputation_0()))
+    {
+        return -1;
+    }
+}