[HLSL] Add implicit binding attribute to resource arrays

clang/include/clang/Basic/Attr.td

@@ -4932,6 +4932,7 @@ def HLSLResourceBinding: InheritableAttr {
         return SpaceNumber;
       }
       void setImplicitBindingOrderID(uint32_t Value) {
+        assert(!hasImplicitBindingOrderID() && "attribute already has implicit binding order id");
         ImplicitBindingOrderID = Value;
       }
       bool hasImplicitBindingOrderID() const {

clang/lib/Sema/SemaHLSL.cpp

@@ -71,6 +71,10 @@ static RegisterType getRegisterType(ResourceClass RC) {
   llvm_unreachable("unexpected ResourceClass value");
 }
 
+static RegisterType getRegisterType(const HLSLAttributedResourceType *ResTy) {
+  return getRegisterType(ResTy->getAttrs().ResourceClass);
+}
+
 // Converts the first letter of string Slot to RegisterType.
 // Returns false if the letter does not correspond to a valid register type.
 static bool convertToRegisterType(StringRef Slot, RegisterType *RT) {
@@ -342,6 +346,16 @@ static bool isResourceRecordTypeOrArrayOf(VarDecl *VD) {
   return Ty->isHLSLResourceRecord() || Ty->isHLSLResourceRecordArray();
 }
 
+static const HLSLAttributedResourceType *
+getResourceArrayHandleType(VarDecl *VD) {
+  assert(VD->getType()->isHLSLResourceRecordArray() &&
+         "expected array of resource records");
+  const Type *Ty = VD->getType()->getUnqualifiedDesugaredType();
+  while (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Ty))
+    Ty = CAT->getArrayElementTypeNoTypeQual()->getUnqualifiedDesugaredType();
+  return HLSLAttributedResourceType::findHandleTypeOnResource(Ty);
+}
+
 // Returns true if the type is a leaf element type that is not valid to be
 // included in HLSL Buffer, such as a resource class, empty struct, zero-sized
 // array, or a builtin intangible type. Returns false it is a valid leaf element
@@ -568,16 +582,13 @@ void createHostLayoutStructForBuffer(Sema &S, HLSLBufferDecl *BufDecl) {
   BufDecl->addLayoutStruct(LS);
 }
 
-static void addImplicitBindingAttrToBuffer(Sema &S, HLSLBufferDecl *BufDecl,
-                                           uint32_t ImplicitBindingOrderID) {
-  RegisterType RT =
-      BufDecl->isCBuffer() ? RegisterType::CBuffer : RegisterType::SRV;
+static void addImplicitBindingAttrToDecl(Sema &S, Decl *D, RegisterType RT,
+                                         uint32_t ImplicitBindingOrderID) {
   auto *Attr =
       HLSLResourceBindingAttr::CreateImplicit(S.getASTContext(), "", "0", {});
-  std::optional<unsigned> RegSlot;
-  Attr->setBinding(RT, RegSlot, 0);
+  Attr->setBinding(RT, std::nullopt, 0);
   Attr->setImplicitBindingOrderID(ImplicitBindingOrderID);
-  BufDecl->addAttr(Attr);
+  D->addAttr(Attr);
 }
 
 // Handle end of cbuffer/tbuffer declaration
@@ -600,7 +611,10 @@ void SemaHLSL::ActOnFinishBuffer(Decl *Dcl, SourceLocation RBrace) {
     if (RBA)
       RBA->setImplicitBindingOrderID(OrderID);
     else
-      addImplicitBindingAttrToBuffer(SemaRef, BufDecl, OrderID);
+      addImplicitBindingAttrToDecl(SemaRef, BufDecl,
+                                   BufDecl->isCBuffer() ? RegisterType::CBuffer
+                                                        : RegisterType::SRV,
+                                   OrderID);
   }
 
   SemaRef.PopDeclContext();
@@ -1906,7 +1920,7 @@ static bool DiagnoseLocalRegisterBinding(Sema &S, SourceLocation &ArgLoc,
   if (const HLSLAttributedResourceType *AttrResType =
           HLSLAttributedResourceType::findHandleTypeOnResource(
               VD->getType().getTypePtr())) {
-    if (RegType == getRegisterType(AttrResType->getAttrs().ResourceClass))
+    if (RegType == getRegisterType(AttrResType))
       return true;
 
     S.Diag(D->getLocation(), diag::err_hlsl_binding_type_mismatch)
@@ -2439,8 +2453,8 @@ void SemaHLSL::ActOnEndOfTranslationUnit(TranslationUnitDecl *TU) {
     HLSLBufferDecl *DefaultCBuffer = HLSLBufferDecl::CreateDefaultCBuffer(
         SemaRef.getASTContext(), SemaRef.getCurLexicalContext(),
         DefaultCBufferDecls);
-    addImplicitBindingAttrToBuffer(SemaRef, DefaultCBuffer,
-                                   getNextImplicitBindingOrderID());
+    addImplicitBindingAttrToDecl(SemaRef, DefaultCBuffer, RegisterType::CBuffer,
+                                 getNextImplicitBindingOrderID());
     SemaRef.getCurLexicalContext()->addDecl(DefaultCBuffer);
     createHostLayoutStructForBuffer(SemaRef, DefaultCBuffer);
 
@@ -3640,6 +3654,24 @@ void SemaHLSL::ActOnVariableDeclarator(VarDecl *VD) {
 
     // process explicit bindings
     processExplicitBindingsOnDecl(VD);
+
+    if (VD->getType()->isHLSLResourceRecordArray()) {
+      // If the resource array does not have an explicit binding attribute,
+      // create an implicit one. It will be used to transfer implicit binding
+      // order_ID to codegen.
+      if (!VD->hasAttr<HLSLVkBindingAttr>()) {
+        HLSLResourceBindingAttr *RBA = VD->getAttr<HLSLResourceBindingAttr>();
+        if (!RBA || !RBA->hasRegisterSlot()) {
+          uint32_t OrderID = getNextImplicitBindingOrderID();
+          if (RBA)
+            RBA->setImplicitBindingOrderID(OrderID);
+          else
+            addImplicitBindingAttrToDecl(
+                SemaRef, VD, getRegisterType(getResourceArrayHandleType(VD)),
+                OrderID);
+        }
+      }
+    }
   }
 
   deduceAddressSpace(VD);

clang/test/AST/HLSL/resource_binding_attr.hlsl

@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -finclude-default-header -ast-dump -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -finclude-default-header -ast-dump -o - %s | FileCheck %s -check-prefixes=CHECK,DXIL
+// RUN: %clang_cc1 -triple spirv-unknown-vulkan-library -finclude-default-header -ast-dump -o - %s | FileCheck %s -check-prefixes=CHECK,SPV
 
 // CHECK: HLSLBufferDecl {{.*}} line:[[# @LINE + 4]]:9 cbuffer CB
 // CHECK-NEXT: HLSLResourceClassAttr {{.*}} Implicit CBuffer
@@ -34,6 +35,10 @@ RWBuffer<float> UAV1 : register(u2), UAV2 : register(u4);
 // CHECK: HLSLResourceBindingAttr {{.*}} "" "space5"
 RWBuffer<float> UAV3 : register(space5);
 
+// CHECK: VarDecl {{.*}} UAV_Array 'RWBuffer<float>[10]'
+// CHECK: HLSLResourceBindingAttr {{.*}} "u10" "space6"
+RWBuffer<float> UAV_Array[10] : register(u10, space6);
+
 //
 // Default constants ($Globals) layout annotations
 
@@ -56,3 +61,44 @@ struct S {
 // CHECK: VarDecl {{.*}} s 'hlsl_constant S'
 // CHECK: HLSLResourceBindingAttr {{.*}} "c10" "space0
 S s : register(c10);
+
+//
+// Implicit binding
+
+// Constant buffers should have implicit binding attribute added by SemaHLSL,
+// unless the target is SPIR-V and there is [[vk::binding]] attribute.
+// CHECK: HLSLBufferDecl {{.*}} line:[[# @LINE + 3]]:9 cbuffer CB2
+// CHECK-NEXT: HLSLResourceClassAttr {{.*}} Implicit CBuffer
+// CHECK-NEXT: HLSLResourceBindingAttr {{.*}} Implicit "" "0"
+cbuffer CB2 {
+  float4 c;
+}
+
+// CHECK: HLSLBufferDecl {{.*}} line:[[# @LINE + 7]]:9 cbuffer CB3
+// CHECK-NEXT: HLSLResourceClassAttr {{.*}} Implicit CBuffer
+// DXIL: HLSLResourceBindingAttr {{.*}} Implicit
+// DXIL-NOT: HLSLVkBindingAttr
+// SPV: HLSLVkBindingAttr {{.*}} 1 0
+// SPV-NOT: HLSLResourceBindingAttr {{.*}} Implicit
+[[vk::binding(1)]]
+cbuffer CB3 {
+  float2 d;
+}
+
+// Resource arrays should have implicit binding attribute added by SemaHLSL,
+// unless the target is SPIR-V and there is [[vk::binding]] attribute.
+// CHECK: VarDecl {{.*}} SB 'StructuredBuffer<float>[10]'
+// CHECK: HLSLResourceBindingAttr {{.*}} Implicit "" "0"
+StructuredBuffer<float> SB[10];
+
+// CHECK: VarDecl {{.*}} SB2 'StructuredBuffer<float>[10]'
+// DXIL: HLSLResourceBindingAttr {{.*}} Implicit
+// DXIL-NOT: HLSLVkBindingAttr
+// SPV: HLSLVkBindingAttr {{.*}} 2 0
+// SPV-NOT: HLSLResourceBindingAttr {{.*}} Implicit
+[[vk::binding(2)]]
+StructuredBuffer<float> SB2[10];
+
+// $Globals should have implicit binding attribute added by SemaHLSL
+// CHECK: HLSLBufferDecl {{.*}} implicit cbuffer $Globals
+// CHECK: HLSLResourceBindingAttr {{.*}} Implicit "" "0"