Emit SPIRV NonReadable decoration for WTexture* (#6922)

3 files changed, 38 insertions, 4 deletions

diff --git a/source/slang/slang-emit-glsl.cpp b/source/slang/slang-emit-glsl.cpp
index 848d9c08d..5e9fa7f70 100644
--- a/source/slang/slang-emit-glsl.cpp
+++ b/source/slang/slang-emit-glsl.cpp
@@ -1837,8 +1837,9 @@ bool GLSLSourceEmitter::tryEmitGlobalParamImpl(IRGlobalParam* varDecl, IRType* v
 
 void GLSLSourceEmitter::emitImageFormatModifierImpl(IRInst* varDecl, IRType* varType)
 {
-    // As a special case, if we are emitting a GLSL declaration
-    // for an HLSL `RWTexture*` then we need to emit a `format` layout qualifier.
+    // Special cases when emitting a GLSL declaration for HLSL/Slang `RWTexture* and `WTexture*`:
+    // - Emit a `format` layout qualifier.
+    // - Emit `writeonly` memory qualifier for `WTexture*`.
 
     if (auto resourceType = as<IRTextureType>(unwrapArray(varType)))
     {
@@ -1855,6 +1856,11 @@ void GLSLSourceEmitter::emitImageFormatModifierImpl(IRInst* varDecl, IRType* var
         default:
             break;
         }
+
+        if (resourceType->getAccess() == SLANG_RESOURCE_ACCESS_WRITE)
+        {
+            m_writer->emit("writeonly\n");
+        }
     }
 }
 
diff --git a/source/slang/slang-emit-spirv.cpp b/source/slang/slang-emit-spirv.cpp
index d07d587e5..e4b5c2f4d 100644
--- a/source/slang/slang-emit-spirv.cpp
+++ b/source/slang/slang-emit-spirv.cpp
@@ -2767,6 +2767,7 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
             param->getDataType(),
             storageClass);
         maybeEmitPointerDecoration(varInst, param);
+        maybeEmitWriteOnlyImageDecoration(varInst, param);
         if (layout)
             emitVarLayout(param, varInst, layout);
         emitDecorations(param, getID(varInst));
@@ -5686,6 +5687,25 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
         maybeEmitPointerDecoration(varInst, inst->getDataType(), as<IRVar>(inst), inst->getOp());
     }
 
+    void maybeEmitWriteOnlyImageDecoration(SpvInst* varInst, IRInst* inst)
+    {
+        auto ptrType = as<IRPtrTypeBase>(inst->getDataType());
+        if (!ptrType)
+            return;
+        auto textureType = as<IRTextureType>(ptrType->getValueType());
+        if (!textureType)
+            return;
+
+        if (textureType->getAccess() == SLANG_RESOURCE_ACCESS_WRITE)
+        {
+            emitOpDecorate(
+                getSection(SpvLogicalSectionID::Annotations),
+                nullptr,
+                getID(varInst),
+                SpvDecorationNonReadable);
+        }
+    }
+
     SpvInst* emitParam(SpvInstParent* parent, IRInst* inst)
     {
         auto paramSpvInst = emitOpFunctionParameter(parent, inst, inst->getFullType());
diff --git a/tests/wgsl/write-only-texture.slang b/tests/wgsl/write-only-texture.slang
index 56034ce6a..7fc9d4266 100644
--- a/tests/wgsl/write-only-texture.slang
+++ b/tests/wgsl/write-only-texture.slang
@@ -1,14 +1,22 @@
 //TEST:REFLECTION(filecheck=REFLECT):-stage compute -entry computeMain -target wgsl -no-codegen
-//TEST:SIMPLE(filecheck=SPV): -target spirv
+//TEST:SIMPLE(filecheck=SPV): -target spirv -emit-spirv-directly
+//TEST:SIMPLE(filecheck=SPV): -target spirv -emit-spirv-via-glsl
 //TEST:SIMPLE(filecheck=CHECK): -target wgsl -entry computeMain -stage compute
 //TEST:SIMPLE(filecheck=CHECK-WGSL-SPV): -target wgsl-spirv-asm -entry computeMain -stage compute
 //TEST:SIMPLE(filecheck=HLSL): -target hlsl -entry computeMain -profile cs_6_0
 //TEST:SIMPLE(filecheck=GLSL): -target glsl -entry computeMain -stage compute
 
 // CHECK: texture_storage_2d<rgba8unorm, write>
+
+// CHECK-WGSL-SPV: OpDecorate {{.*}} NonReadable
 // CHECK-WGSL-SPV: OpTypeImage %float 2D {{.}} 0 0 2 Rgba8
+
+// SPV: OpDecorate {{.*}} NonReadable
 // SPV: OpTypeImage %float 2D {{.}} 0 0 2 Rgba8
+
 // HLSL: RWTexture2D
+
+// GLSL: writeonly
 // GLSL: image2D
 
 // REFLECT: "name": "writeOnlyTexture"
@@ -21,4 +29,4 @@ WTexture2D writeOnlyTexture;
 void computeMain()
 {
     writeOnlyTexture.Store(int2(0,0), float4(0.2, 0.3, 0.4, 1.0));
-}
\ No newline at end of file
+}