Add datalayout for constant buffers. (#5608)

* Add datalayout for constant buffers.

* Fixes.

* Fix test.

* Fix glsl codegen.

* Update spirv-specific doc.

* Fix test.

* Fix binding in the presense of specialization constants.

* address comments.

* Add a test for constant buffer layout.

1 files changed, 10 insertions, 1 deletions

diff --git a/source/slang/slang-ir-entry-point-uniforms.cpp b/source/slang/slang-ir-entry-point-uniforms.cpp
index 0dfdc2d8e..b3073a97d 100644
--- a/source/slang/slang-ir-entry-point-uniforms.cpp
+++ b/source/slang/slang-ir-entry-point-uniforms.cpp
@@ -403,7 +403,16 @@ struct CollectEntryPointUniformParams : PerEntryPointPass
             // If we need a constant buffer, then the global
             // shader parameter will be a `ConstantBuffer<paramStructType>`
             //
-            auto constantBufferType = builder.getConstantBufferType(paramStructType);
+            IRType* layoutType = nullptr;
+
+            if (m_options.targetReq->getOptionSet().getBoolOption(
+                    CompilerOptionName::GLSLForceScalarLayout))
+                layoutType = builder.getType(kIROp_ScalarBufferLayoutType);
+            else if (isKhronosTarget(m_options.targetReq))
+                layoutType = builder.getType(kIROp_Std430BufferLayoutType);
+            else
+                layoutType = builder.getType(kIROp_DefaultBufferLayoutType);
+            auto constantBufferType = builder.getConstantBufferType(paramStructType, layoutType);
             collectedParam = builder.createParam(constantBufferType);
         }
         else