[SPIR-V] Support sizeof(vk::BufferPointer)

This commit enables sizeof operator support for vk::BufferPointer types.
It updates SemaExpr to allow vk::BufferPointer in sizeof expressions,
and modifies ASTContext to correctly report the size and alignment of
vk::BufferPointer as equivalent to uint64_t.

Fixes #7998

Author: s-perron

tools/clang/lib/AST/ASTContext.cpp

@@ -40,6 +40,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/MathExtras.h" // HLSL Change
+#include "clang/AST/HlslTypes.h" // HLSL Change
 #include <map>
 
 using namespace clang;
@@ -1804,6 +1805,17 @@ TypeInfo ASTContext::getTypeInfoImpl(const Type *T) const {
 
     const RecordType *RT = cast<RecordType>(TT);
     const RecordDecl *RD = RT->getDecl();
+    // HLSL Change Begins
+#ifdef ENABLE_SPIRV_CODEGEN
+    if (hlsl::IsVKBufferPointerType(QualType(T, 0))) {
+      TypeInfo Info = getTypeInfo(UnsignedLongLongTy);
+      Width = Info.Width;
+      Align = Info.Align;
+      AlignIsRequired = Info.AlignIsRequired;
+      break;
+    }
+#endif
+    // HLSL Change Ends
     const ASTRecordLayout &Layout = getASTRecordLayout(RD);
     Width = toBits(Layout.getSize());
     Align = toBits(Layout.getAlignment());

tools/clang/lib/Sema/SemaExpr.cpp

@@ -45,6 +45,7 @@
 #include "clang/Sema/Template.h"
 #include "llvm/Support/ConvertUTF.h"
 #include "clang/Sema/SemaHLSL.h" // HLSL Change
+#include "clang/AST/HlslTypes.h" // HLSL Change
 using namespace clang;
 using namespace sema;
 
@@ -3820,6 +3821,13 @@ bool Sema::CheckHLSLUnaryExprOrTypeTraitOperand(QualType ExprType,
     return true;
   }
 
+  // vk::BufferPointer is allowed in sizeof
+#ifdef ENABLE_SPIRV_CODEGEN
+  if (hlsl::IsVKBufferPointerType(ExprType)) {
+    return false;
+  }
+#endif
+
   if (!hlsl::IsHLSLNumericOrAggregateOfNumericType(ExprType)) {
     Diag(Loc, diag::err_hlsl_sizeof_nonnumeric) << ExprType;
     return true;

tools/clang/test/CodeGenSPIRV/vk.buffer-pointer.sizeof.hlsl

@@ -0,0 +1,13 @@
+// RUN: %dxc -T cs_6_0 -E main -fcgl %s -spirv | FileCheck %s
+
+struct S {
+    float a;
+};
+
+[numthreads(1, 1, 1)]
+void main() {
+    vk::BufferPointer<S> p = vk::BufferPointer<S>(0);
+    // CHECK: %uint_8 = OpConstant %uint 8
+    // CHECK: OpStore %size %uint_8
+    uint size = sizeof(p);
+}