test that link time extern struct layouts are visible for nested types (#6568)

closes https://github.com/shader-slang/slang/issues/6556

1 files changed, 241 insertions, 0 deletions

diff --git a/tools/gfx-unit-test/link-time-type-layout-nested.cpp b/tools/gfx-unit-test/link-time-type-layout-nested.cpp
new file mode 100644
index 000000000..b6ea0e64d
--- /dev/null
+++ b/tools/gfx-unit-test/link-time-type-layout-nested.cpp
@@ -0,0 +1,241 @@
+#include "core/slang-blob.h"
+#include "gfx-test-util.h"
+#include "slang-gfx.h"
+#include "unit-test/slang-unit-test.h"
+
+using namespace gfx;
+
+namespace gfx_test
+{
+
+static void diagnoseIfNeeded(Slang::ComPtr<slang::IBlob>& diagnosticsBlob)
+{
+    if (diagnosticsBlob && diagnosticsBlob->getBufferSize() > 0)
+    {
+        fprintf(stderr, "%s\n", (const char*)diagnosticsBlob->getBufferPointer());
+    }
+}
+
+static Slang::Result loadProgram(
+    gfx::IDevice* device,
+    Slang::ComPtr<gfx::IShaderProgram>& outShaderProgram,
+    slang::ProgramLayout*& slangReflection)
+{
+    // main.slang: declares the interface, extern struct Inner, and Outer struct with Inner field
+    const char* mainSrc = R"(
+        // Define an interface
+        public interface IFoo
+        {
+            public float4 getFoo();
+        };
+
+        // Define an extern struct that implements the interface
+        public extern struct Inner : IFoo;
+
+        // Define a regular struct that contains an Inner field
+        public struct Outer
+        {
+            float2 position;
+            Inner innerData;
+            float2 texCoord;
+        };
+
+        // Vertex shader entry point that takes an Outer parameter
+        [shader("vertex")]
+        float4 vertexMain(Outer params) : SV_Position
+        {
+            return float4(params.position, 0.0f, 1.0f) + params.innerData.getFoo();
+        }
+    )";
+
+    // inner.slang: defines Inner with its field layout and its implementation of getFoo()
+    const char* innerSrc = R"(
+        import main;
+
+        // Define the implementation of Inner with its field layout
+        export public struct Inner : IFoo
+        {
+            public float4 getFoo() { return this.data; }
+            float4 data;
+        }
+    )";
+
+    Slang::ComPtr<slang::ISession> slangSession;
+    SLANG_RETURN_ON_FAIL(device->getSlangSession(slangSession.writeRef()));
+    Slang::ComPtr<slang::IBlob> diagnosticsBlob;
+
+    // Create blobs for the two modules
+    auto mainBlob = Slang::UnownedRawBlob::create(mainSrc, strlen(mainSrc));
+    auto innerBlob = Slang::UnownedRawBlob::create(innerSrc, strlen(innerSrc));
+
+    // Load modules from source
+    slang::IModule* mainModule = slangSession->loadModuleFromSource("main", "main.slang", mainBlob);
+    slang::IModule* innerModule =
+        slangSession->loadModuleFromSource("inner", "inner.slang", innerBlob);
+
+    // Find the entry point from main.slang
+    Slang::ComPtr<slang::IEntryPoint> vsEntryPoint;
+    SLANG_RETURN_ON_FAIL(mainModule->findEntryPointByName("vertexMain", vsEntryPoint.writeRef()));
+
+    // Compose the program from both modules and the entry point
+    Slang::List<slang::IComponentType*> componentTypes;
+    componentTypes.add(mainModule);
+    componentTypes.add(innerModule);
+    componentTypes.add(vsEntryPoint);
+
+    Slang::ComPtr<slang::IComponentType> composedProgram;
+    SLANG_RETURN_ON_FAIL(slangSession->createCompositeComponentType(
+        componentTypes.getBuffer(),
+        componentTypes.getCount(),
+        composedProgram.writeRef(),
+        diagnosticsBlob.writeRef()));
+    diagnoseIfNeeded(diagnosticsBlob);
+
+    // Link the composite program
+    Slang::ComPtr<slang::IComponentType> linkedProgram;
+    SLANG_RETURN_ON_FAIL(
+        composedProgram->link(linkedProgram.writeRef(), diagnosticsBlob.writeRef()));
+    diagnoseIfNeeded(diagnosticsBlob);
+
+    // Retrieve the reflection information
+    composedProgram = linkedProgram;
+    slangReflection = composedProgram->getLayout();
+
+    // Create a shader program
+    gfx::IShaderProgram::Desc programDesc = {};
+    programDesc.slangGlobalScope = composedProgram.get();
+    auto shaderProgram = device->createProgram(programDesc);
+    outShaderProgram = shaderProgram;
+
+    return SLANG_OK;
+}
+
+// Function to validate the type layout of Outer struct with nested Inner struct
+static void validateNestedExternStructLayout(
+    UnitTestContext* context,
+    slang::ProgramLayout* slangReflection)
+{
+    // Check reflection is available
+    SLANG_CHECK(slangReflection != nullptr);
+
+    // Get the entry point layout for vertexMain
+    slang::EntryPointLayout* entryPointLayout = slangReflection->findEntryPointByName("vertexMain");
+
+    SLANG_CHECK_MSG(entryPointLayout != nullptr, "Could not find vertexMain entry point");
+
+    // Get the parameter count for the entry point
+    auto paramCount = entryPointLayout->getParameterCount();
+    SLANG_CHECK_MSG(paramCount >= 1, "Entry point has no parameters");
+
+    // Get the first parameter, which should be of type Outer
+    auto paramLayout = entryPointLayout->getParameterByIndex(0);
+    SLANG_CHECK_MSG(paramLayout != nullptr, "Could not get first parameter layout");
+
+    // Get the type layout of the parameter
+    auto outerTypeLayout = paramLayout->getTypeLayout();
+    SLANG_CHECK_MSG(outerTypeLayout != nullptr, "Parameter has no type layout");
+
+    // Check if it's a struct type
+    auto kind = outerTypeLayout->getKind();
+    SLANG_CHECK_MSG(kind == slang::TypeReflection::Kind::Struct, "Parameter is not a struct type");
+
+    // Verify Outer has 3 fields: position, innerData, texCoord
+    auto fieldCount = outerTypeLayout->getFieldCount();
+    SLANG_CHECK_MSG(fieldCount == 3, "Outer struct does not have 3 fields");
+
+    // Find and check the innerData field
+    slang::VariableLayoutReflection* innerDataField = nullptr;
+    for (unsigned int i = 0; i < fieldCount; i++)
+    {
+        auto fieldLayout = outerTypeLayout->getFieldByIndex(i);
+        const char* fieldName = fieldLayout->getName();
+
+        if (fieldName && strcmp(fieldName, "innerData") == 0)
+        {
+            innerDataField = fieldLayout;
+            break;
+        }
+    }
+
+    SLANG_CHECK_MSG(innerDataField != nullptr, "Could not find innerData field in Outer struct");
+
+    // Get the type layout of the innerData field
+    auto innerTypeLayout = innerDataField->getTypeLayout();
+    SLANG_CHECK_MSG(innerTypeLayout != nullptr, "innerData field has no type layout");
+
+    // Verify Inner is a struct type
+    kind = innerTypeLayout->getKind();
+    SLANG_CHECK_MSG(kind == slang::TypeReflection::Kind::Struct, "Inner is not a struct type");
+
+    // Verify Inner has 1 field (data)
+    fieldCount = innerTypeLayout->getFieldCount();
+    SLANG_CHECK_MSG(fieldCount == 1, "Inner struct does not have 1 field");
+
+    // Find and check the data field in Inner
+    bool foundDataField = false;
+    for (unsigned int i = 0; i < fieldCount; i++)
+    {
+        auto fieldLayout = innerTypeLayout->getFieldByIndex(i);
+        const char* fieldName = fieldLayout->getName();
+
+        if (fieldName && strcmp(fieldName, "data") == 0)
+        {
+            foundDataField = true;
+
+            // Check that it's a float4 type
+            auto fieldTypeLayout = fieldLayout->getTypeLayout();
+            auto fieldTypeKind = fieldTypeLayout->getKind();
+
+            SLANG_CHECK_MSG(
+                fieldTypeKind == slang::TypeReflection::Kind::Vector,
+                "Field 'data' is not a vector type");
+
+            auto elementCount = fieldTypeLayout->getElementCount();
+            SLANG_CHECK_MSG(elementCount == 4, "Field 'data' is not a 4-element vector");
+
+            break;
+        }
+    }
+
+    SLANG_CHECK_MSG(foundDataField, "Could not find field 'data' in Inner struct");
+}
+
+void linkTimeTypeLayoutNestedImpl(gfx::IDevice* device, UnitTestContext* context)
+{
+    Slang::ComPtr<gfx::IShaderProgram> shaderProgram;
+    slang::ProgramLayout* slangReflection = nullptr;
+
+    auto result = loadProgram(device, shaderProgram, slangReflection);
+    SLANG_CHECK(SLANG_SUCCEEDED(result));
+
+    // Validate the nested struct layout
+    validateNestedExternStructLayout(context, slangReflection);
+
+    // Create a graphics pipeline to verify everything works
+    GraphicsPipelineStateDesc pipelineDesc = {};
+    pipelineDesc.program = shaderProgram.get();
+    pipelineDesc.primitiveType = PrimitiveType::Triangle;
+
+    ComPtr<gfx::IPipelineState> pipelineState;
+    auto pipelineResult =
+        device->createGraphicsPipelineState(pipelineDesc, pipelineState.writeRef());
+    SLANG_CHECK(SLANG_SUCCEEDED(pipelineResult));
+}
+
+//
+// This test verifies that type layout information correctly propagates through
+// the Slang compilation pipeline when a regular struct contains a field whose type
+// is an extern struct defined in another module.
+// Specifically, it tests that:
+//
+// 1. The Outer struct correctly includes the Inner extern struct as a field
+// 2. After linking, the Inner struct's layout is properly resolved with its field
+// 3. The complete type layout information is available in the reflection data
+//
+
+SLANG_UNIT_TEST(linkTimeTypeLayoutNested)
+{
+    runTestImpl(linkTimeTypeLayoutNestedImpl, unitTestContext, Slang::RenderApiFlag::Vulkan);
+}
+
+} // namespace gfx_test