Fix duplicate SPIRV decorations. (#4346)

* Fix duplicate `DescriptorSet` decorations.

* Fix duplicate `Block` decoration.

3 files changed, 38 insertions, 20 deletions

diff --git a/source/slang/slang-emit-spirv.cpp b/source/slang/slang-emit-spirv.cpp
index 10c263793..df60feecf 100644
--- a/source/slang/slang-emit-spirv.cpp
+++ b/source/slang/slang-emit-spirv.cpp
@@ -2139,6 +2139,7 @@ struct SPIRVEmitContext
     {
         bool needDefaultSetBindingDecoration = false;
         bool hasExplicitSetBinding = false;
+        bool isDescirptorSetDecorated = false;
         for (auto rr : layout->getOffsetAttrs())
         {
             UInt index = rr->getOffset();
@@ -2200,32 +2201,40 @@ struct SPIRVEmitContext
                     nullptr,
                     varInst,
                     SpvLiteralInteger::from32(int32_t(index)));
-                if (space)
+                if (!isDescirptorSetDecorated)
+                {
+                    if (space)
+                    {
+                        emitOpDecorateDescriptorSet(
+                            getSection(SpvLogicalSectionID::Annotations),
+                            nullptr,
+                            varInst,
+                            SpvLiteralInteger::from32(int32_t(space)));
+                        isDescirptorSetDecorated = true;
+                    }
+                    else
+                    {
+                        needDefaultSetBindingDecoration = true;
+                    }
+                }
+                break;
+            case LayoutResourceKind::RegisterSpace:
+                if (!isDescirptorSetDecorated)
                 {
                     emitOpDecorateDescriptorSet(
                         getSection(SpvLogicalSectionID::Annotations),
                         nullptr,
                         varInst,
-                        SpvLiteralInteger::from32(int32_t(space)));
+                        SpvLiteralInteger::from32(int32_t(index)));
+                    hasExplicitSetBinding = true;
+                    isDescirptorSetDecorated = true;
                 }
-                else
-                {
-                    needDefaultSetBindingDecoration = true;
-                }
-                break;
-            case LayoutResourceKind::RegisterSpace:
-                emitOpDecorateDescriptorSet(
-                    getSection(SpvLogicalSectionID::Annotations),
-                    nullptr,
-                    varInst,
-                    SpvLiteralInteger::from32(int32_t(index)));
-                hasExplicitSetBinding = true;
                 break;
             default:
                 break;
             }
         }
-        if (needDefaultSetBindingDecoration && !hasExplicitSetBinding)
+        if (needDefaultSetBindingDecoration && !hasExplicitSetBinding && !isDescirptorSetDecorated)
         {
             emitOpDecorateDescriptorSet(
                 getSection(SpvLogicalSectionID::Annotations),
diff --git a/source/slang/slang-ir-insts.h b/source/slang/slang-ir-insts.h
index d63c6878e..bc86fa7ee 100644
--- a/source/slang/slang-ir-insts.h
+++ b/source/slang/slang-ir-insts.h
@@ -328,6 +328,8 @@ IR_SIMPLE_DECORATION(VulkanHitObjectAttributesDecoration)
 
 IR_SIMPLE_DECORATION(PerVertexDecoration)
 
+IR_SIMPLE_DECORATION(SPIRVBlockDecoration)
+
 struct IRRequireGLSLVersionDecoration : IRDecoration
 {
     enum { kOp = kIROp_RequireGLSLVersionDecoration };
@@ -4342,6 +4344,13 @@ public:
         return addDecoration(value, op, (IRInst* const*) nullptr, 0);
     }
 
+    IRDecoration* addDecorationIfNotExist(IRInst* value, IROp op)
+    {
+        if (auto decor = value->findDecorationImpl(op))
+            return decor;
+        return addDecoration(value, op);
+    }
+
     IRDecoration* addDecoration(IRInst* value, IROp op, IRInst* operand)
     {
         return addDecoration(value, op, &operand, 1);
diff --git a/source/slang/slang-ir-spirv-legalize.cpp b/source/slang/slang-ir-spirv-legalize.cpp
index 44c5bae7b..989790b13 100644
--- a/source/slang/slang-ir-spirv-legalize.cpp
+++ b/source/slang/slang-ir-spirv-legalize.cpp
@@ -137,9 +137,9 @@ struct SPIRVLegalizationContext : public SourceEmitterBase
         }
         builder.addNameHintDecoration(structType, nameSb.getUnownedSlice());
         if (m_sharedContext->isSpirv14OrLater())
-            builder.addDecoration(structType, kIROp_SPIRVBlockDecoration);
+            builder.addDecorationIfNotExist(structType, kIROp_SPIRVBlockDecoration);
         else
-            builder.addDecoration(structType, kIROp_SPIRVBufferBlockDecoration);
+            builder.addDecorationIfNotExist(structType, kIROp_SPIRVBufferBlockDecoration);
 
         result.structType = structType;
         result.arrayKey = arrayKey;
@@ -594,7 +594,7 @@ struct SPIRVLegalizationContext : public SourceEmitterBase
                 {
                     innerType = wrapConstantBufferElement(inst);
                 }
-                builder.addDecoration(innerType, kIROp_SPIRVBlockDecoration);
+                builder.addDecorationIfNotExist(innerType, kIROp_SPIRVBlockDecoration);
                 
                 auto varLayoutInst = inst->findDecoration<IRLayoutDecoration>();
                 if (paramBlockType)
@@ -650,12 +650,12 @@ struct SPIRVLegalizationContext : public SourceEmitterBase
                 innerType = glslShaderStorageBufferType->getElementType();
                 if (m_sharedContext->isSpirv14OrLater())
                 {
-                    builder.addDecoration(innerType, kIROp_SPIRVBlockDecoration);
+                    builder.addDecorationIfNotExist(innerType, kIROp_SPIRVBlockDecoration);
                     storageClass = SpvStorageClassStorageBuffer;
                 }
                 else
                 {
-                    builder.addDecoration(innerType, kIROp_SPIRVBufferBlockDecoration);
+                    builder.addDecorationIfNotExist(innerType, kIROp_SPIRVBufferBlockDecoration);
                     storageClass = SpvStorageClassUniform;
                 }
                 needLoad = false;