[HLSL][SPIRV] Add vk::binding attribute

clang/include/clang/Basic/Attr.td

@@ -4894,6 +4894,14 @@ def HLSLSV_GroupIndex: HLSLAnnotationAttr {
   let Documentation = [HLSLSV_GroupIndexDocs];
 }
 
+def HLSLVkBinding : InheritableAttr {
+  let Spellings = [CXX11<"vk", "binding">];
+  let Subjects = SubjectList<[HLSLBufferObj, ExternalGlobalVar], ErrorDiag>;
+  let Args = [IntArgument<"Binding">, IntArgument<"Set", 1>];
+  let LangOpts = [HLSL];
+  let Documentation = [HLSLVkBindingDocs];
+}
+
 def HLSLResourceBinding: InheritableAttr {
   let Spellings = [HLSLAnnotation<"register">];
   let Subjects = SubjectList<[HLSLBufferObj, ExternalGlobalVar], ErrorDiag>;

clang/include/clang/Basic/AttrDocs.td

@@ -8778,6 +8778,32 @@ def ReadOnlyPlacementDocs : Documentation {
   }];
 }
 
+def HLSLVkBindingDocs : Documentation {
+  let Category = DocCatVariable;
+  let Content = [{
+The ``[[vk::binding]]`` attribute allows you to explicitly specify the descriptor
+set and binding for a resource when targeting SPIR-V. This is particularly
+useful when you need different bindings for SPIR-V and DXIL, as the ``register``
+attribute can be used for DXIL-specific bindings.
+
+The attribute takes two integer arguments: the binding and the descriptor set.
+The descriptor set is optional and defaults to 0 if not provided.
+
+.. code-block:: c++
+
+  // A structured buffer with binding 23 in descriptor set 102.
+  [[vk::binding(23, 102)]] StructuredBuffer<float> Buf;
+
+  // A structured buffer with binding 14 in descriptor set 0.
+  [[vk::binding(14)]] StructuredBuffer<float> Buf2;
+
+  // A cbuffer with binding 1 in descriptor set 2.
+  [[vk::binding(1, 2)]] cbuffer MyCBuffer {
+    float4x4 worldViewProj;
+  };
+  }];
+}
+
 def WebAssemblyFuncrefDocs : Documentation {
   let Category = DocCatType;
   let Content = [{

clang/include/clang/Parse/Parser.h

@@ -5191,7 +5191,7 @@ class Parser : public CodeCompletionHandler {
   void ParseHLSLAnnotations(ParsedAttributes &Attrs,
                             SourceLocation *EndLoc = nullptr,
                             bool CouldBeBitField = false);
-  Decl *ParseHLSLBuffer(SourceLocation &DeclEnd);
+  Decl *ParseHLSLBuffer(SourceLocation &DeclEnd, ParsedAttributes &Attrs);
 
   ///@}
 

clang/include/clang/Sema/SemaHLSL.h

@@ -161,6 +161,7 @@ class SemaHLSL : public SemaBase {
   void handleNumThreadsAttr(Decl *D, const ParsedAttr &AL);
   void handleWaveSizeAttr(Decl *D, const ParsedAttr &AL);
   void handleVkConstantIdAttr(Decl *D, const ParsedAttr &AL);
+  void handleVkBindingAttr(Decl *D, const ParsedAttr &AL);
   void handleSV_DispatchThreadIDAttr(Decl *D, const ParsedAttr &AL);
   void handleSV_GroupThreadIDAttr(Decl *D, const ParsedAttr &AL);
   void handleSV_GroupIDAttr(Decl *D, const ParsedAttr &AL);

clang/lib/CodeGen/CGHLSLRuntime.cpp

@@ -273,10 +273,14 @@ void CGHLSLRuntime::addBuffer(const HLSLBufferDecl *BufDecl) {
   emitBufferGlobalsAndMetadata(BufDecl, BufGV);
 
   // Initialize cbuffer from binding (implicit or explicit)
-  HLSLResourceBindingAttr *RBA = BufDecl->getAttr<HLSLResourceBindingAttr>();
-  assert(RBA &&
-         "cbuffer/tbuffer should always have resource binding attribute");
-  initializeBufferFromBinding(BufDecl, BufGV, RBA);
+  if (HLSLVkBindingAttr *VkBinding = BufDecl->getAttr<HLSLVkBindingAttr>()) {
+    initializeBufferFromBinding(BufDecl, BufGV, VkBinding);
+  } else {
+    HLSLResourceBindingAttr *RBA = BufDecl->getAttr<HLSLResourceBindingAttr>();
+    assert(RBA &&
+           "cbuffer/tbuffer should always have resource binding attribute");
+    initializeBufferFromBinding(BufDecl, BufGV, RBA);
+  }
 }
 
 llvm::TargetExtType *
@@ -593,6 +597,31 @@ static void initializeBuffer(CodeGenModule &CGM, llvm::GlobalVariable *GV,
   CGM.AddCXXGlobalInit(InitResFunc);
 }
 
+static Value *buildNameForResource(llvm::StringRef BaseName,
+                                   CodeGenModule &CGM) {
+  std::string Str(BaseName);
+  std::string GlobalName(Str + ".str");
+  return CGM.GetAddrOfConstantCString(Str, GlobalName.c_str()).getPointer();
+}
+
+void CGHLSLRuntime::initializeBufferFromBinding(const HLSLBufferDecl *BufDecl,
+                                                llvm::GlobalVariable *GV,
+                                                HLSLVkBindingAttr *VkBinding) {
+  assert(VkBinding && "expect a nonnull binding attribute");
+  llvm::Type *Int1Ty = llvm::Type::getInt1Ty(CGM.getLLVMContext());
+  auto *NonUniform = llvm::ConstantInt::get(Int1Ty, false);
+  auto *Index = llvm::ConstantInt::get(CGM.IntTy, 0);
+  auto *RangeSize = llvm::ConstantInt::get(CGM.IntTy, 1);
+  auto *Set = llvm::ConstantInt::get(CGM.IntTy, VkBinding->getSet());
+  auto *Binding = llvm::ConstantInt::get(CGM.IntTy, VkBinding->getBinding());
+  Value *Name = buildNameForResource(BufDecl->getName(), CGM);
+  llvm::Intrinsic::ID IntrinsicID =
+      CGM.getHLSLRuntime().getCreateHandleFromBindingIntrinsic();
+
+  SmallVector<Value *> Args{Set, Binding, RangeSize, Index, NonUniform, Name};
+  initializeBuffer(CGM, GV, IntrinsicID, Args);
+}
+
 void CGHLSLRuntime::initializeBufferFromBinding(const HLSLBufferDecl *BufDecl,
                                                 llvm::GlobalVariable *GV,
                                                 HLSLResourceBindingAttr *RBA) {

clang/lib/CodeGen/CGHLSLRuntime.h

@@ -62,6 +62,7 @@ class VarDecl;
 class ParmVarDecl;
 class InitListExpr;
 class HLSLBufferDecl;
+class HLSLVkBindingAttr;
 class HLSLResourceBindingAttr;
 class Type;
 class RecordType;
@@ -166,6 +167,9 @@ class CGHLSLRuntime {
 private:
   void emitBufferGlobalsAndMetadata(const HLSLBufferDecl *BufDecl,
                                     llvm::GlobalVariable *BufGV);
+  void initializeBufferFromBinding(const HLSLBufferDecl *BufDecl,
+                                   llvm::GlobalVariable *GV,
+                                   HLSLVkBindingAttr *VkBinding);
   void initializeBufferFromBinding(const HLSLBufferDecl *BufDecl,
                                    llvm::GlobalVariable *GV,
                                    HLSLResourceBindingAttr *RBA);

clang/lib/Parse/ParseDecl.cpp

@@ -1901,7 +1901,7 @@ Parser::DeclGroupPtrTy Parser::ParseDeclaration(DeclaratorContext Context,
 
   case tok::kw_cbuffer:
   case tok::kw_tbuffer:
-    SingleDecl = ParseHLSLBuffer(DeclEnd);
+    SingleDecl = ParseHLSLBuffer(DeclEnd, DeclAttrs);
     break;
   case tok::kw_namespace:
     ProhibitAttributes(DeclAttrs);

clang/lib/Parse/ParseHLSL.cpp

@@ -48,7 +48,8 @@ static bool validateDeclsInsideHLSLBuffer(Parser::DeclGroupPtrTy DG,
   return IsValid;
 }
 
-Decl *Parser::ParseHLSLBuffer(SourceLocation &DeclEnd) {
+Decl *Parser::ParseHLSLBuffer(SourceLocation &DeclEnd,
+                              ParsedAttributes &Attrs) {
   assert((Tok.is(tok::kw_cbuffer) || Tok.is(tok::kw_tbuffer)) &&
          "Not a cbuffer or tbuffer!");
   bool IsCBuffer = Tok.is(tok::kw_cbuffer);
@@ -62,7 +63,6 @@ Decl *Parser::ParseHLSLBuffer(SourceLocation &DeclEnd) {
   IdentifierInfo *Identifier = Tok.getIdentifierInfo();
   SourceLocation IdentifierLoc = ConsumeToken();
 
-  ParsedAttributes Attrs(AttrFactory);
   MaybeParseHLSLAnnotations(Attrs, nullptr);
 
   ParseScope BufferScope(this, Scope::DeclScope);

clang/lib/Sema/SemaDeclAttr.cpp

@@ -7441,6 +7441,9 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
   case ParsedAttr::AT_HLSLVkConstantId:
     S.HLSL().handleVkConstantIdAttr(D, AL);
     break;
+  case ParsedAttr::AT_HLSLVkBinding:
+    S.HLSL().handleVkBindingAttr(D, AL);
+    break;
   case ParsedAttr::AT_HLSLSV_GroupThreadID:
     S.HLSL().handleSV_GroupThreadIDAttr(D, AL);
     break;

clang/lib/Sema/SemaHLSL.cpp

@@ -596,8 +596,9 @@ void SemaHLSL::ActOnFinishBuffer(Decl *Dcl, SourceLocation RBrace) {
   // create buffer layout struct
   createHostLayoutStructForBuffer(SemaRef, BufDecl);
 
+  HLSLVkBindingAttr *VkBinding = Dcl->getAttr<HLSLVkBindingAttr>();
   HLSLResourceBindingAttr *RBA = Dcl->getAttr<HLSLResourceBindingAttr>();
-  if (!RBA || !RBA->hasRegisterSlot()) {
+  if (!VkBinding && (!RBA || !RBA->hasRegisterSlot())) {
     SemaRef.Diag(Dcl->getLocation(), diag::warn_hlsl_implicit_binding);
     // Use HLSLResourceBindingAttr to transfer implicit binding order_ID
     // to codegen. If it does not exist, create an implicit attribute.
@@ -1479,6 +1480,23 @@ void SemaHLSL::handleVkConstantIdAttr(Decl *D, const ParsedAttr &AL) {
     D->addAttr(NewAttr);
 }
 
+void SemaHLSL::handleVkBindingAttr(Decl *D, const ParsedAttr &AL) {
+  // The vk::binding attribute only applies to SPIR-V.
+  if (!getASTContext().getTargetInfo().getTriple().isSPIRV())
+    return;
+
+  uint32_t Binding = 0;
+  if (!SemaRef.checkUInt32Argument(AL, AL.getArgAsExpr(0), Binding))
+    return;
+  uint32_t Set = 0;
+  if (AL.getNumArgs() > 1 &&
+      !SemaRef.checkUInt32Argument(AL, AL.getArgAsExpr(1), Set))
+    return;
+
+  D->addAttr(::new (getASTContext())
+                 HLSLVkBindingAttr(getASTContext(), AL, Binding, Set));
+}
+
 bool SemaHLSL::diagnoseInputIDType(QualType T, const ParsedAttr &AL) {
   const auto *VT = T->getAs<VectorType>();
 
@@ -3643,8 +3661,12 @@ static bool initVarDeclWithCtor(Sema &S, VarDecl *VD,
 bool SemaHLSL::initGlobalResourceDecl(VarDecl *VD) {
   std::optional<uint32_t> RegisterSlot;
   uint32_t SpaceNo = 0;
+  HLSLVkBindingAttr *VkBinding = VD->getAttr<HLSLVkBindingAttr>();
   HLSLResourceBindingAttr *RBA = VD->getAttr<HLSLResourceBindingAttr>();
-  if (RBA) {
+  if (VkBinding) {
+    RegisterSlot = VkBinding->getBinding();
+    SpaceNo = VkBinding->getSet();
+  } else if (RBA) {
     if (RBA->hasRegisterSlot())
       RegisterSlot = RBA->getSlotNumber();
     SpaceNo = RBA->getSpaceNumber();
@@ -3747,6 +3769,9 @@ void SemaHLSL::processExplicitBindingsOnDecl(VarDecl *VD) {
 
   bool HasBinding = false;
   for (Attr *A : VD->attrs()) {
+    if (isa<HLSLVkBindingAttr>(A))
+      HasBinding = true;
+
     HLSLResourceBindingAttr *RBA = dyn_cast<HLSLResourceBindingAttr>(A);
     if (!RBA || !RBA->hasRegisterSlot())
       continue;

clang/test/AST/HLSL/vk_binding_attr.hlsl

@@ -0,0 +1,70 @@
+// RUN: %clang_cc1 -triple spirv-unknown-vulkan1.3-library -finclude-default-header -ast-dump -o - %s | FileCheck %s -check-prefixes=SPV,CHECK
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.8-library -finclude-default-header -ast-dump -o - %s | FileCheck %s -check-prefixes=DXIL,CHECK
+
+// CHECK: VarDecl {{.*}} Buf 'StructuredBuffer<float>':'hlsl::StructuredBuffer<float>'
+// SPV-NEXT: CXXConstructExpr {{.*}} 'StructuredBuffer<float>':'hlsl::StructuredBuffer<float>' 'void (unsigned int, unsigned int, int, unsigned int, const char *)'
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 23
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 102
+// DXIL-NEXT: CXXConstructExpr {{.*}} 'StructuredBuffer<float>':'hlsl::StructuredBuffer<float>' 'void (unsigned int, int, unsigned int, unsigned int, const char *)'
+// DXIL-NEXT: IntegerLiteral {{.*}} 'unsigned int' 0
+// DXIL-NEXT: IntegerLiteral {{.*}} 'int' 1
+// SPV: HLSLVkBindingAttr {{.*}} 23 102
+// DXIL-NOT: HLSLVkBindingAttr
+[[vk::binding(23, 102)]] StructuredBuffer<float> Buf;
+
+// CHECK: VarDecl {{.*}} Buf2 'StructuredBuffer<float>':'hlsl::StructuredBuffer<float>'
+// CHECK-NEXT: CXXConstructExpr {{.*}} 'StructuredBuffer<float>':'hlsl::StructuredBuffer<float>' 'void (unsigned int, unsigned int, int, unsigned int, const char *)'
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 14
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 1
+// DXIL-NEXT: IntegerLiteral {{.*}} 'unsigned int' 23
+// DXIL-NEXT: IntegerLiteral {{.*}} 'unsigned int' 102
+// SPV: HLSLVkBindingAttr {{.*}} 14 1
+// DXIL-NOT: HLSLVkBindingAttr
+// CHECK: HLSLResourceBindingAttr {{.*}} "t23" "space102"
+[[vk::binding(14, 1)]] StructuredBuffer<float> Buf2 : register(t23, space102);
+
+// CHECK: VarDecl {{.*}} Buf3 'StructuredBuffer<float>':'hlsl::StructuredBuffer<float>'
+// CHECK-NEXT: CXXConstructExpr {{.*}} 'StructuredBuffer<float>':'hlsl::StructuredBuffer<float>' 'void (unsigned int, unsigned int, int, unsigned int, const char *)'
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 14
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 0
+// DXIL-NEXT: IntegerLiteral {{.*}} 'unsigned int' 23
+// DXIL-NEXT: IntegerLiteral {{.*}} 'unsigned int' 102
+// SPV: HLSLVkBindingAttr {{.*}} 14 0
+// DXIL-NOT: HLSLVkBindingAttr
+// CHECK: HLSLResourceBindingAttr {{.*}} "t23" "space102"
+[[vk::binding(14)]] StructuredBuffer<float> Buf3 : register(t23, space102);
+
+// CHECK: HLSLBufferDecl {{.*}} cbuffer CB
+// CHECK-NEXT: HLSLResourceClassAttr {{.*}} Implicit CBuffer
+// SPV-NEXT: HLSLVkBindingAttr {{.*}} 1 2
+// DXIL-NOT: HLSLVkBindingAttr
+[[vk::binding(1, 2)]] cbuffer CB {
+  float a;
+}
+
+// CHECK: VarDecl {{.*}} Buf4 'Buffer<int>':'hlsl::Buffer<int>'
+// SPV-NEXT: CXXConstructExpr {{.*}} 'Buffer<int>':'hlsl::Buffer<int>' 'void (unsigned int, unsigned int, int, unsigned int, const char *)'
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 24
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 103
+// DXL-NEXT: CXXConstructExpr {{.*}} 'Buffer<int>':'hlsl::Buffer<int>' 'void (unsigned int, int, unsigned int, unsigned int, const char *)'
+// SPV: HLSLVkBindingAttr {{.*}} 24 103
+// DXIL-NOT: HLSLVkBindingAttr
+[[vk::binding(24, 103)]] Buffer<int> Buf4;
+
+// CHECK: VarDecl {{.*}} Buf5 'RWBuffer<int2>':'hlsl::RWBuffer<vector<int, 2>>'
+// SPV-NEXT: CXXConstructExpr {{.*}} 'RWBuffer<int2>':'hlsl::RWBuffer<vector<int, 2>>' 'void (unsigned int, unsigned int, int, unsigned int, const char *)'
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 25
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 104
+// DXL-NEXT: CXXConstructExpr {{.*}} 'Buffer<int>':'hlsl::Buffer<int>' 'void (unsigned int, int, unsigned int, unsigned int, const char *)'
+// SPV: HLSLVkBindingAttr {{.*}} 25 104
+// DXIL-NOT: HLSLVkBindingAttr
+[[vk::binding(25, 104)]] RWBuffer<int2> Buf5;
+
+// CHECK: VarDecl {{.*}} Buf6 'RWStructuredBuffer<int>':'hlsl::RWStructuredBuffer<int>'
+// SPV-NEXT: CXXConstructExpr {{.*}} 'RWStructuredBuffer<int>':'hlsl::RWStructuredBuffer<int>' 'void (unsigned int, unsigned int, int, unsigned int, const char *)'
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 26
+// SPV-NEXT: IntegerLiteral {{.*}} 'unsigned int' 105
+// DXL-NEXT: CXXConstructExpr {{.*}} 'Buffer<int>':'hlsl::Buffer<int>' 'void (unsigned int, int, unsigned int, unsigned int, const char *)'
+// SPV: HLSLVkBindingAttr {{.*}} 26 105
+// DXIL-NOT: HLSLVkBindingAttr
+[[vk::binding(26, 105)]] RWStructuredBuffer<int> Buf6;

clang/test/CodeGenHLSL/vk_binding_attr.hlsl

@@ -0,0 +1,44 @@
+// RUN: %clang_cc1 -triple spirv-unknown-vulkan1.3-library -finclude-default-header -O3 -emit-llvm -o - %s | FileCheck %s
+// CHECK: [[Buf:@.*]] = private unnamed_addr constant [4 x i8] c"Buf\00"
+// CHECK: [[Buf2:@.*]] = private unnamed_addr constant [5 x i8] c"Buf2\00"
+// CHECK: [[Buf3:@.*]] = private unnamed_addr constant [5 x i8] c"Buf3\00"
+// CHECK: [[CB:@.*]] = private unnamed_addr constant [3 x i8] c"CB\00"
+// CHECK: [[CB2:@.*]] = private unnamed_addr constant [4 x i8] c"CB2\00"
+// CHECK: [[Buf4:@.*]] = private unnamed_addr constant [5 x i8] c"Buf4\00"
+// CHECK: [[Buf5:@.*]] = private unnamed_addr constant [5 x i8] c"Buf5\00"
+// CHECK: [[Buf6:@.*]] = private unnamed_addr constant [5 x i8] c"Buf6\00"
+
+[[vk::binding(23, 102)]] StructuredBuffer<float> Buf;
+[[vk::binding(14, 1)]] StructuredBuffer<float> Buf2 : register(t23, space102);
+[[vk::binding(14)]] StructuredBuffer<float> Buf3 : register(t23, space102);
+
+[[vk::binding(1, 2)]] cbuffer CB {
+  float a;
+};
+
+[[vk::binding(10,20)]] cbuffer CB2 {
+  float b;
+};
+
+
+[[vk::binding(24, 103)]] Buffer<int> Buf4;
+[[vk::binding(25, 104)]] RWBuffer<int2> Buf5;
+[[vk::binding(26, 105)]] RWStructuredBuffer<float> Buf6;
+
+[numthreads(1,1,1)]
+void main() {
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 102, i32 23, {{.*}} [[Buf]])
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 1, i32 14, {{.*}} [[Buf2]])
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 0, i32 14, {{.*}} [[Buf3]])
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 2, i32 1, {{.*}} [[CB]])
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 20, i32 10, {{.*}} [[CB2]])
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 103, i32 24, {{.*}} [[Buf4]])
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 104, i32 25, {{.*}} [[Buf5]])
+// CHECK: call {{.*}} @llvm.spv.resource.handlefrombinding{{.*}}(i32 105, i32 26, {{.*}} [[Buf6]])
+  float f1 = Buf.Load(0);
+  float f2 = Buf2.Load(0);
+  float f3 = Buf3.Load(0);
+  int i = Buf4.Load(0);
+  Buf5[0] = i;
+  Buf6[0] = f1+f2+f3+a+b;
+}