[HLSL][SPIR-V] Implement vk::push_constant

TODO:
  - get the wg-hlsl proposal accepted.
  - fill this description.
  - add tests

Author: Keenuts

clang/include/clang/Basic/AddressSpaces.h

@@ -62,6 +62,7 @@ enum class LangAS : unsigned {
   hlsl_private,
   hlsl_device,
   hlsl_input,
+  hlsl_push_constant,
 
   // Wasm specific address spaces.
   wasm_funcref,

clang/include/clang/Basic/Attr.td

@@ -5154,6 +5154,14 @@ def HLSLVkExtBuiltinInput : InheritableAttr {
   let Documentation = [HLSLVkExtBuiltinInputDocs];
 }
 
+def HLSLVkPushConstant : InheritableAttr {
+  let Spellings = [CXX11<"vk", "push_constant">];
+  let Args = [];
+  let Subjects = SubjectList<[GlobalVar], ErrorDiag>;
+  let LangOpts = [HLSL];
+  let Documentation = [HLSLVkPushConstantDocs];
+}
+
 def HLSLVkConstantId : InheritableAttr {
   let Spellings = [CXX11<"vk", "constant_id">];
   let Args = [IntArgument<"Id">];

clang/include/clang/Basic/AttrDocs.td

@@ -8838,6 +8838,11 @@ https://github.com/microsoft/hlsl-specs/blob/main/proposals/0011-inline-spirv.md
   }];
 }
 
+def HLSLVkPushConstantDocs : Documentation {
+  let Category = DocCatVariable;
+  let Content = [{ FIXME }];
+}
+
 def AnnotateTypeDocs : Documentation {
   let Category = DocCatType;
   let Heading = "annotate_type";

clang/include/clang/Basic/HLSLRuntime.h

@@ -14,6 +14,7 @@
 #ifndef CLANG_BASIC_HLSLRUNTIME_H
 #define CLANG_BASIC_HLSLRUNTIME_H
 
+#include "clang/Basic/AddressSpaces.h"
 #include "clang/Basic/LangOptions.h"
 #include <cstdint>
 
@@ -30,6 +31,10 @@ getStageFromEnvironment(const llvm::Triple::EnvironmentType &E) {
   return static_cast<ShaderStage>(Pipeline);
 }
 
+constexpr bool isInitializedByPipeline(LangAS AS) {
+  return AS == LangAS::hlsl_input || AS == LangAS::hlsl_push_constant;
+}
+
 #define ENUM_COMPARE_ASSERT(Value)                                             \
   static_assert(                                                               \
       getStageFromEnvironment(llvm::Triple::Value) == ShaderStage::Value,      \

clang/include/clang/Sema/SemaHLSL.h

@@ -197,6 +197,7 @@ class SemaHLSL : public SemaBase {
   void handleSemanticAttr(Decl *D, const ParsedAttr &AL);
 
   void handleVkExtBuiltinInputAttr(Decl *D, const ParsedAttr &AL);
+  void handleVkPushConstantAttr(Decl *D, const ParsedAttr &AL);
 
   bool CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
   QualType ProcessResourceTypeAttributes(QualType Wrapped);

clang/lib/AST/Type.cpp

@@ -101,6 +101,7 @@ bool Qualifiers::isTargetAddressSpaceSupersetOf(LangAS A, LangAS B,
          (A == LangAS::Default && B == LangAS::hlsl_private) ||
          (A == LangAS::Default && B == LangAS::hlsl_device) ||
          (A == LangAS::Default && B == LangAS::hlsl_input) ||
+         (A == LangAS::Default && B == LangAS::hlsl_push_constant) ||
          // Conversions from target specific address spaces may be legal
          // depending on the target information.
          Ctx.getTargetInfo().isAddressSpaceSupersetOf(A, B);

clang/lib/AST/TypePrinter.cpp

@@ -2749,6 +2749,8 @@ std::string Qualifiers::getAddrSpaceAsString(LangAS AS) {
     return "hlsl_device";
   case LangAS::hlsl_input:
     return "hlsl_input";
+  case LangAS::hlsl_push_constant:
+    return "hlsl_push_constant";
   case LangAS::wasm_funcref:
     return "__funcref";
   default:

clang/lib/Basic/TargetInfo.cpp

@@ -52,6 +52,7 @@ static const LangASMap FakeAddrSpaceMap = {
     15, // hlsl_private
     16, // hlsl_device
     17, // hlsl_input
+    18, // hlsl_push_constant
     20, // wasm_funcref
 };
 

clang/lib/Basic/Targets/AArch64.h

@@ -48,6 +48,7 @@ static const unsigned ARM64AddrSpaceMap[] = {
     0, // hlsl_private
     0, // hlsl_device
     0, // hlsl_input
+    0, // hlsl_push_constant
     // Wasm address space values for this target are dummy values,
     // as it is only enabled for Wasm targets.
     20, // wasm_funcref

clang/lib/Basic/Targets/AMDGPU.cpp

@@ -63,6 +63,7 @@ const LangASMap AMDGPUTargetInfo::AMDGPUDefIsGenMap = {
     llvm::AMDGPUAS::PRIVATE_ADDRESS, // hlsl_private
     llvm::AMDGPUAS::GLOBAL_ADDRESS,  // hlsl_device
     llvm::AMDGPUAS::PRIVATE_ADDRESS, // hlsl_input
+    llvm::AMDGPUAS::GLOBAL_ADDRESS,  // hlsl_push_constant
 };
 
 const LangASMap AMDGPUTargetInfo::AMDGPUDefIsPrivMap = {
@@ -91,6 +92,7 @@ const LangASMap AMDGPUTargetInfo::AMDGPUDefIsPrivMap = {
     llvm::AMDGPUAS::PRIVATE_ADDRESS,  // hlsl_private
     llvm::AMDGPUAS::GLOBAL_ADDRESS,   // hlsl_device
     llvm::AMDGPUAS::PRIVATE_ADDRESS,  // hlsl_input
+    llvm::AMDGPUAS::GLOBAL_ADDRESS,   // hlsl_push_constant
 };
 } // namespace targets
 } // namespace clang