Revert "[HLSL] Support packoffset attribute in AST (#89836)" (#91473)

This reverts commit c5509fe.

Author: python3kgae

clang/include/clang/Basic/Attr.td

@@ -4415,18 +4415,6 @@ def HLSLResourceBinding: InheritableAttr {
   let Documentation = [HLSLResourceBindingDocs];
 }
 
-def HLSLPackOffset: HLSLAnnotationAttr {
-  let Spellings = [HLSLAnnotation<"packoffset">];
-  let LangOpts = [HLSL];
-  let Args = [IntArgument<"Subcomponent">, IntArgument<"Component">];
-  let Documentation = [HLSLPackOffsetDocs];
-  let AdditionalMembers = [{
-      unsigned getOffset() {
-        return subcomponent * 4 + component;
-      }
-  }];
-}
-
 def HLSLSV_DispatchThreadID: HLSLAnnotationAttr {
   let Spellings = [HLSLAnnotation<"SV_DispatchThreadID">];
   let Subjects = SubjectList<[ParmVar, Field]>;

clang/include/clang/Basic/AttrDocs.td

@@ -7408,26 +7408,6 @@ The full documentation is available here: https://docs.microsoft.com/en-us/windo
   }];
 }
 
-def HLSLPackOffsetDocs : Documentation {
-  let Category = DocCatFunction;
-  let Content = [{
-The packoffset attribute is used to change the layout of a cbuffer.
-Attribute spelling in HLSL is: ``packoffset( c[Subcomponent][.component] )``.
-A subcomponent is a register number, which is an integer. A component is in the form of [.xyzw].
-
-Examples:
-
-.. code-block:: c++
-
-  cbuffer A {
-    float3 a : packoffset(c0.y);
-    float4 b : packoffset(c4);
-  }
-
-The full documentation is available here: https://learn.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-variable-packoffset
-  }];
-}
-
 def HLSLSV_DispatchThreadIDDocs : Documentation {
   let Category = DocCatFunction;
   let Content = [{

clang/include/clang/Basic/DiagnosticGroups.td

@@ -1507,9 +1507,6 @@ def BranchProtection : DiagGroup<"branch-protection">;
 // Warnings for HLSL Clang extensions
 def HLSLExtension : DiagGroup<"hlsl-extensions">;
 
-// Warning for mix packoffset and non-packoffset.
-def HLSLMixPackOffset : DiagGroup<"mix-packoffset">;
-
 // Warnings for DXIL validation
 def DXILValidation : DiagGroup<"dxil-validation">;
 

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -1754,7 +1754,5 @@ def err_hlsl_separate_attr_arg_and_number : Error<"wrong argument format for hls
 def ext_hlsl_access_specifiers : ExtWarn<
   "access specifiers are a clang HLSL extension">,
   InGroup<HLSLExtension>;
-def err_hlsl_unsupported_component : Error<"invalid component '%0' used; expected 'x', 'y', 'z', or 'w'">;
-def err_hlsl_packoffset_invalid_reg : Error<"invalid resource class specifier '%0' for packoffset, expected 'c'">;
 
 } // end of Parser diagnostics

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -12184,11 +12184,6 @@ def err_hlsl_init_priority_unsupported : Error<
 def err_hlsl_unsupported_register_type : Error<"invalid resource class specifier '%0' used; expected 'b', 's', 't', or 'u'">;
 def err_hlsl_unsupported_register_number : Error<"register number should be an integer">;
 def err_hlsl_expected_space : Error<"invalid space specifier '%0' used; expected 'space' followed by an integer, like space1">;
-def warn_hlsl_packoffset_mix : Warning<"cannot mix packoffset elements with nonpackoffset elements in a cbuffer">,
-    InGroup<HLSLMixPackOffset>;
-def err_hlsl_packoffset_overlap : Error<"packoffset overlap between %0, %1">;
-def err_hlsl_packoffset_cross_reg_boundary : Error<"packoffset cannot cross register boundary">;
-def err_hlsl_packoffset_alignment_mismatch : Error<"packoffset at 'y' not match alignment %0 required by %1">;
 def err_hlsl_pointers_unsupported : Error<
   "%select{pointers|references}0 are unsupported in HLSL">;
 

clang/lib/Parse/ParseHLSL.cpp

@@ -183,94 +183,6 @@ void Parser::ParseHLSLAnnotations(ParsedAttributes &Attrs,
       return;
     }
   } break;
-  case ParsedAttr::AT_HLSLPackOffset: {
-    // Parse 'packoffset( c[Subcomponent][.component] )'.
-    // Check '('.
-    if (ExpectAndConsume(tok::l_paren, diag::err_expected_lparen_after)) {
-      SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-      return;
-    }
-    // Check c[Subcomponent] as an identifier.
-    if (!Tok.is(tok::identifier)) {
-      Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
-      SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-      return;
-    }
-    StringRef OffsetStr = Tok.getIdentifierInfo()->getName();
-    SourceLocation SubComponentLoc = Tok.getLocation();
-    if (OffsetStr[0] != 'c') {
-      Diag(Tok.getLocation(), diag::err_hlsl_packoffset_invalid_reg)
-          << OffsetStr;
-      SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-      return;
-    }
-    OffsetStr = OffsetStr.substr(1);
-    unsigned SubComponent = 0;
-    if (!OffsetStr.empty()) {
-      // Make sure SubComponent is a number.
-      if (OffsetStr.getAsInteger(10, SubComponent)) {
-        Diag(SubComponentLoc.getLocWithOffset(1),
-             diag::err_hlsl_unsupported_register_number);
-        SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-        return;
-      }
-    }
-    unsigned Component = 0;
-    ConsumeToken(); // consume identifier.
-    SourceLocation ComponentLoc;
-    if (Tok.is(tok::period)) {
-      ConsumeToken(); // consume period.
-      if (!Tok.is(tok::identifier)) {
-        Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
-        SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-        return;
-      }
-      StringRef ComponentStr = Tok.getIdentifierInfo()->getName();
-      ComponentLoc = Tok.getLocation();
-      ConsumeToken(); // consume identifier.
-      // Make sure Component is a single character.
-      if (ComponentStr.size() != 1) {
-        Diag(ComponentLoc, diag::err_hlsl_unsupported_component)
-            << ComponentStr;
-        SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-        return;
-      }
-      switch (ComponentStr[0]) {
-      case 'x':
-      case 'r':
-        Component = 0;
-        break;
-      case 'y':
-      case 'g':
-        Component = 1;
-        break;
-      case 'z':
-      case 'b':
-        Component = 2;
-        break;
-      case 'w':
-      case 'a':
-        Component = 3;
-        break;
-      default:
-        Diag(ComponentLoc, diag::err_hlsl_unsupported_component)
-            << ComponentStr;
-        SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-        return;
-      }
-    }
-    ASTContext &Ctx = Actions.getASTContext();
-    QualType SizeTy = Ctx.getSizeType();
-    uint64_t SizeTySize = Ctx.getTypeSize(SizeTy);
-    ArgExprs.push_back(IntegerLiteral::Create(
-        Ctx, llvm::APInt(SizeTySize, SubComponent), SizeTy, SubComponentLoc));
-    ArgExprs.push_back(IntegerLiteral::Create(
-        Ctx, llvm::APInt(SizeTySize, Component), SizeTy, ComponentLoc));
-    if (ExpectAndConsume(tok::r_paren, diag::err_expected)) {
-      SkipUntil(tok::r_paren, StopAtSemi); // skip through )
-      return;
-    }
-  } break;
   case ParsedAttr::UnknownAttribute:
     Diag(Loc, diag::err_unknown_hlsl_semantic) << II;
     return;

clang/lib/Sema/SemaDeclAttr.cpp

@@ -7309,55 +7309,6 @@ static void handleHLSLSV_DispatchThreadIDAttr(Sema &S, Decl *D,
   D->addAttr(::new (S.Context) HLSLSV_DispatchThreadIDAttr(S.Context, AL));
 }
 
-static void handleHLSLPackOffsetAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
-  if (!isa<VarDecl>(D) || !isa<HLSLBufferDecl>(D->getDeclContext())) {
-    S.Diag(AL.getLoc(), diag::err_hlsl_attr_invalid_ast_node)
-        << AL << "shader constant in a constant buffer";
-    return;
-  }
-
-  uint32_t SubComponent;
-  if (!checkUInt32Argument(S, AL, AL.getArgAsExpr(0), SubComponent))
-    return;
-  uint32_t Component;
-  if (!checkUInt32Argument(S, AL, AL.getArgAsExpr(1), Component))
-    return;
-
-  QualType T = cast<VarDecl>(D)->getType().getCanonicalType();
-  // Check if T is an array or struct type.
-  // TODO: mark matrix type as aggregate type.
-  bool IsAggregateTy = (T->isArrayType() || T->isStructureType());
-
-  // Check Component is valid for T.
-  if (Component) {
-    unsigned Size = S.getASTContext().getTypeSize(T);
-    if (IsAggregateTy || Size > 128) {
-      S.Diag(AL.getLoc(), diag::err_hlsl_packoffset_cross_reg_boundary);
-      return;
-    } else {
-      // Make sure Component + sizeof(T) <= 4.
-      if ((Component * 32 + Size) > 128) {
-        S.Diag(AL.getLoc(), diag::err_hlsl_packoffset_cross_reg_boundary);
-        return;
-      }
-      QualType EltTy = T;
-      if (const auto *VT = T->getAs<VectorType>())
-        EltTy = VT->getElementType();
-      unsigned Align = S.getASTContext().getTypeAlign(EltTy);
-      if (Align > 32 && Component == 1) {
-        // NOTE: Component 3 will hit err_hlsl_packoffset_cross_reg_boundary.
-        // So we only need to check Component 1 here.
-        S.Diag(AL.getLoc(), diag::err_hlsl_packoffset_alignment_mismatch)
-            << Align << EltTy;
-        return;
-      }
-    }
-  }
-
-  D->addAttr(::new (S.Context)
-                 HLSLPackOffsetAttr(S.Context, AL, SubComponent, Component));
-}
-
 static void handleHLSLShaderAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   StringRef Str;
   SourceLocation ArgLoc;
@@ -9779,9 +9730,6 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
   case ParsedAttr::AT_HLSLSV_DispatchThreadID:
     handleHLSLSV_DispatchThreadIDAttr(S, D, AL);
     break;
-  case ParsedAttr::AT_HLSLPackOffset:
-    handleHLSLPackOffsetAttr(S, D, AL);
-    break;
   case ParsedAttr::AT_HLSLShader:
     handleHLSLShaderAttr(S, D, AL);
     break;

clang/lib/Sema/SemaHLSL.cpp

@@ -39,89 +39,9 @@ Decl *SemaHLSL::ActOnStartBuffer(Scope *BufferScope, bool CBuffer,
   return Result;
 }
 
-// Calculate the size of a legacy cbuffer type based on
-// https://learn.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-packing-rules
-static unsigned calculateLegacyCbufferSize(const ASTContext &Context,
-                                           QualType T) {
-  unsigned Size = 0;
-  constexpr unsigned CBufferAlign = 128;
-  if (const RecordType *RT = T->getAs<RecordType>()) {
-    const RecordDecl *RD = RT->getDecl();
-    for (const FieldDecl *Field : RD->fields()) {
-      QualType Ty = Field->getType();
-      unsigned FieldSize = calculateLegacyCbufferSize(Context, Ty);
-      unsigned FieldAlign = 32;
-      if (Ty->isAggregateType())
-        FieldAlign = CBufferAlign;
-      Size = llvm::alignTo(Size, FieldAlign);
-      Size += FieldSize;
-    }
-  } else if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
-    if (unsigned ElementCount = AT->getSize().getZExtValue()) {
-      unsigned ElementSize =
-          calculateLegacyCbufferSize(Context, AT->getElementType());
-      unsigned AlignedElementSize = llvm::alignTo(ElementSize, CBufferAlign);
-      Size = AlignedElementSize * (ElementCount - 1) + ElementSize;
-    }
-  } else if (const VectorType *VT = T->getAs<VectorType>()) {
-    unsigned ElementCount = VT->getNumElements();
-    unsigned ElementSize =
-        calculateLegacyCbufferSize(Context, VT->getElementType());
-    Size = ElementSize * ElementCount;
-  } else {
-    Size = Context.getTypeSize(T);
-  }
-  return Size;
-}
-
 void SemaHLSL::ActOnFinishBuffer(Decl *Dcl, SourceLocation RBrace) {
   auto *BufDecl = cast<HLSLBufferDecl>(Dcl);
   BufDecl->setRBraceLoc(RBrace);
-
-  // Validate packoffset.
-  llvm::SmallVector<std::pair<VarDecl *, HLSLPackOffsetAttr *>> PackOffsetVec;
-  bool HasPackOffset = false;
-  bool HasNonPackOffset = false;
-  for (auto *Field : BufDecl->decls()) {
-    VarDecl *Var = dyn_cast<VarDecl>(Field);
-    if (!Var)
-      continue;
-    if (Field->hasAttr<HLSLPackOffsetAttr>()) {
-      PackOffsetVec.emplace_back(Var, Field->getAttr<HLSLPackOffsetAttr>());
-      HasPackOffset = true;
-    } else {
-      HasNonPackOffset = true;
-    }
-  }
-
-  if (HasPackOffset && HasNonPackOffset)
-    Diag(BufDecl->getLocation(), diag::warn_hlsl_packoffset_mix);
-
-  if (HasPackOffset) {
-    ASTContext &Context = getASTContext();
-    // Make sure no overlap in packoffset.
-    // Sort PackOffsetVec by offset.
-    std::sort(PackOffsetVec.begin(), PackOffsetVec.end(),
-              [](const std::pair<VarDecl *, HLSLPackOffsetAttr *> &LHS,
-                 const std::pair<VarDecl *, HLSLPackOffsetAttr *> &RHS) {
-                return LHS.second->getOffset() < RHS.second->getOffset();
-              });
-
-    for (unsigned i = 0; i < PackOffsetVec.size() - 1; i++) {
-      VarDecl *Var = PackOffsetVec[i].first;
-      HLSLPackOffsetAttr *Attr = PackOffsetVec[i].second;
-      unsigned Size = calculateLegacyCbufferSize(Context, Var->getType());
-      unsigned Begin = Attr->getOffset() * 32;
-      unsigned End = Begin + Size;
-      unsigned NextBegin = PackOffsetVec[i + 1].second->getOffset() * 32;
-      if (End > NextBegin) {
-        VarDecl *NextVar = PackOffsetVec[i + 1].first;
-        Diag(NextVar->getLocation(), diag::err_hlsl_packoffset_overlap)
-            << NextVar << Var;
-      }
-    }
-  }
-
   SemaRef.PopDeclContext();
 }