Only define global heap variables in 6.6+ (microsoft#4011)

RsourceDescriptorHeap and SamplerDescriptorHeap were predefined in all
shader models, not just 6.6+. By checking the shader model version
before declaring them, we can limit this to relevant shader models.

Added tests for 6.6 and 6.5 behavior when these are redefined

Author: pow2clk

tools/clang/lib/Sema/SemaHLSL.cpp

@@ -3508,6 +3508,8 @@ class HLSLExternalSource : public ExternalSemaSource {
     TypeSourceInfo *float4TypeSourceInfo = m_context->getTrivialTypeSourceInfo(float4Type, NoLoc);
     m_objectTypeLazyInitMask = 0;
     unsigned effectKindIndex = 0;
+    const auto *SM =
+        hlsl::ShaderModel::GetByName(m_sema->getLangOpts().HLSLProfile.c_str());
     for (unsigned i = 0; i < _countof(g_ArBasicKindsAsTypes); i++)
     {
       ArBasicKind kind = g_ArBasicKindsAsTypes[i];
@@ -3566,14 +3568,18 @@ class HLSLExternalSource : public ExternalSemaSource {
         recordDecl = DeclareRayQueryType(*m_context);
       } else if (kind == AR_OBJECT_HEAP_RESOURCE) {
         recordDecl = DeclareResourceType(*m_context, /*bSampler*/false);
-        // create Resource ResourceDescriptorHeap;
-        DeclareBuiltinGlobal("ResourceDescriptorHeap",
-                             m_context->getRecordType(recordDecl), *m_context);
+        if (SM->IsSM66Plus()) {
+          // create Resource ResourceDescriptorHeap;
+          DeclareBuiltinGlobal("ResourceDescriptorHeap",
+                               m_context->getRecordType(recordDecl), *m_context);
+        }
       } else if (kind == AR_OBJECT_HEAP_SAMPLER) {
         recordDecl = DeclareResourceType(*m_context, /*bSampler*/true);
-        // create Resource SamplerDescriptorHeap;
-        DeclareBuiltinGlobal("SamplerDescriptorHeap",
-                             m_context->getRecordType(recordDecl), *m_context);
+        if (SM->IsSM66Plus()) {
+          // create Resource SamplerDescriptorHeap;
+          DeclareBuiltinGlobal("SamplerDescriptorHeap",
+                               m_context->getRecordType(recordDecl), *m_context);
+        }
 
       }
       else if (kind == AR_OBJECT_FEEDBACKTEXTURE2D) {

tools/clang/test/HLSLFileCheck/hlsl/intrinsics/createHandleFromHeap/redefine_heap_vars.hlsl

@@ -0,0 +1,25 @@
+// RUN: %dxc -T ps_6_5 %s | %FileCheck %s
+// RUN: %dxc -T ps_6_6 %s | %FileCheck %s -check-prefix=FAIL
+
+// Make sure that global heap variable redeclaration fails
+// on 6.6 and passes on previous shader models
+
+// FAIL: error: redefinition of 'ResourceDescriptorHeap' with a different type: 'Texture2D<float> []' vs '.Resource'
+// FAIL: error: redefinition of 'SamplerDescriptorHeap' with a different type: 'SamplerState []' vs '.Sampler'
+
+// Verify that feature bits aren't set and the shader produce roughly reasonable code
+// CHECK-NOT: Resource descriptor heap indexing
+// CHECK-NOT: Sampler descriptor heap indexing
+// CHECK: @main
+// CHECK: @dx.op.sample.f32
+
+Texture2D<float> ResourceDescriptorHeap[] : register(t0);
+SamplerState SamplerDescriptorHeap[] : register(s0);
+
+uint ID;
+float main(float4 pos: SV_Position): SV_Target {
+  Texture2D<float> tex = ResourceDescriptorHeap[ID];
+  SamplerState samp = SamplerDescriptorHeap[ID];
+  return tex.Sample(samp, pos.xy);
+}
+