[HLSL] Translate cbuffer declarations to target type dx.CBuffer - initial commit

Author: hekota

clang/include/clang/AST/Decl.h

@@ -5032,6 +5032,9 @@ class HLSLBufferDecl final : public NamedDecl, public DeclContext {
   SourceLocation KwLoc;
   /// IsCBuffer - Whether the buffer is a cbuffer (and not a tbuffer).
   bool IsCBuffer;
+  /// HasValidPackoffset - Whether the buffer has valid packoffset annotations
+  //                       on all declarations
+  bool HasPackoffset;
 
   HLSLBufferDecl(DeclContext *DC, bool CBuffer, SourceLocation KwLoc,
                  IdentifierInfo *ID, SourceLocation IDLoc,
@@ -5052,6 +5055,9 @@ class HLSLBufferDecl final : public NamedDecl, public DeclContext {
   SourceLocation getRBraceLoc() const { return RBraceLoc; }
   void setRBraceLoc(SourceLocation L) { RBraceLoc = L; }
   bool isCBuffer() const { return IsCBuffer; }
+  void setHasPackoffset(bool PO) { HasPackoffset = PO; }
+  bool hasPackoffset() const { return HasPackoffset; }
+  const CXXRecordDecl *getLayoutStruct() const;
 
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Decl *D) { return classofKind(D->getKind()); }

clang/include/clang/AST/Type.h

@@ -6266,8 +6266,8 @@ class HLSLAttributedResourceType : public Type, public llvm::FoldingSetNode {
     LLVM_PREFERRED_TYPE(bool)
     uint8_t RawBuffer : 1;
 
-    Attributes(llvm::dxil::ResourceClass ResourceClass, bool IsROV,
-               bool RawBuffer)
+    Attributes(llvm::dxil::ResourceClass ResourceClass, bool IsROV = false,
+               bool RawBuffer = false)
         : ResourceClass(ResourceClass), IsROV(IsROV), RawBuffer(RawBuffer) {}
 
     Attributes() : Attributes(llvm::dxil::ResourceClass::UAV, false, false) {}

clang/lib/AST/Decl.cpp

@@ -1747,6 +1747,10 @@ void NamedDecl::printNestedNameSpecifier(raw_ostream &OS,
       }
     }
 
+    // Suppress transparent contexts like export or HLSLBufferDecl context
+    if (Ctx->isTransparentContext())
+      continue;
+
     // Skip non-named contexts such as linkage specifications and ExportDecls.
     const NamedDecl *ND = dyn_cast<NamedDecl>(Ctx);
     if (!ND)
@@ -5713,7 +5717,7 @@ HLSLBufferDecl::HLSLBufferDecl(DeclContext *DC, bool CBuffer,
                                SourceLocation IDLoc, SourceLocation LBrace)
     : NamedDecl(Decl::Kind::HLSLBuffer, DC, IDLoc, DeclarationName(ID)),
       DeclContext(Decl::Kind::HLSLBuffer), LBraceLoc(LBrace), KwLoc(KwLoc),
-      IsCBuffer(CBuffer) {}
+      IsCBuffer(CBuffer), HasPackoffset(false) {}
 
 HLSLBufferDecl *HLSLBufferDecl::Create(ASTContext &C,
                                        DeclContext *LexicalParent, bool CBuffer,
@@ -5743,6 +5747,17 @@ HLSLBufferDecl *HLSLBufferDecl::CreateDeserialized(ASTContext &C,
                                     SourceLocation(), SourceLocation());
 }
 
+const CXXRecordDecl *HLSLBufferDecl::getLayoutStruct() const {
+  // Layout struct is the last decl in the HLSLBufferDecl.
+  if (CXXRecordDecl *RD = llvm::dyn_cast_or_null<CXXRecordDecl>(LastDecl)) {
+    assert(RD->getName().starts_with(
+               ("__cblayout_" + getIdentifier()->getName()).str()) &&
+           "expected buffer layout struct");
+    return RD;
+  }
+  llvm_unreachable("HLSL buffer is missing a layout struct");
+}
+
 //===----------------------------------------------------------------------===//
 // ImportDecl Implementation
 //===----------------------------------------------------------------------===//