[NFC][Matrix][Clang][HLSL] Move MaxMatrixDimension to a LangOpt

fixes #160190

This change just makes MaxMatrixDimension configurable by language mode.
It was previously introduced in 94b4311
when there was not a need to make dimensions configurable.

Current testing to this effect exists in:
- clang/test/Sema/matrix-type-builtins.c
- clang/test/SemaCXX/matrix-type-builtins.cpp
- clang/test/SemaHLSL/BuiltIns/matrix-basic_types-errors.hlsl

I considered adding a driver flag to `clang/include/clang/Driver/Options.td`
but HLSL matrix max dim is always 4 so we don't need this configurable
beyond that size for our use case.

Author: farzonl

clang/include/clang/AST/TypeBase.h

@@ -4378,8 +4378,6 @@ class ConstantMatrixType final : public MatrixType {
   unsigned NumRows;
   unsigned NumColumns;
 
-  static constexpr unsigned MaxElementsPerDimension = (1 << 20) - 1;
-
   ConstantMatrixType(QualType MatrixElementType, unsigned NRows,
                      unsigned NColumns, QualType CanonElementType);
 
@@ -4398,16 +4396,6 @@ class ConstantMatrixType final : public MatrixType {
     return getNumRows() * getNumColumns();
   }
 
-  /// Returns true if \p NumElements is a valid matrix dimension.
-  static constexpr bool isDimensionValid(size_t NumElements) {
-    return NumElements > 0 && NumElements <= MaxElementsPerDimension;
-  }
-
-  /// Returns the maximum number of elements per dimension.
-  static constexpr unsigned getMaxElementsPerDimension() {
-    return MaxElementsPerDimension;
-  }
-
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, getElementType(), getNumRows(), getNumColumns(),
             getTypeClass());

clang/include/clang/Basic/LangOptions.def

@@ -432,6 +432,7 @@ ENUM_LANGOPT(RegisterStaticDestructors, RegisterStaticDestructorsKind, 2,
 LANGOPT(RegCall4, 1, 0, NotCompatible, "Set __regcall4 as a default calling convention to respect __regcall ABI v.4")
 
 LANGOPT(MatrixTypes, 1, 0, NotCompatible, "Enable or disable the builtin matrix type")
+VALUE_LANGOPT(MaxMatrixDimension, 32, (1 << 20) - 1, NotCompatible, "maximum allowed matrix dimension")
 
 LANGOPT(CXXAssumptions, 1, 1, NotCompatible, "Enable or disable codegen and compile-time checks for C++23's [[assume]] attribute")
 

clang/lib/AST/ASTContext.cpp

@@ -4713,8 +4713,8 @@ QualType ASTContext::getConstantMatrixType(QualType ElementTy, unsigned NumRows,
 
   assert(MatrixType::isValidElementType(ElementTy) &&
          "need a valid element type");
-  assert(ConstantMatrixType::isDimensionValid(NumRows) &&
-         ConstantMatrixType::isDimensionValid(NumColumns) &&
+  assert(NumRows > 0 && NumRows <= LangOpts.MaxMatrixDimension &&
+         NumColumns > 0 && NumColumns <= LangOpts.MaxMatrixDimension &&
          "need valid matrix dimensions");
   void *InsertPos = nullptr;
   if (ConstantMatrixType *MTP = MatrixTypes.FindNodeOrInsertPos(ID, InsertPos))

clang/lib/Basic/LangOptions.cpp

@@ -131,8 +131,12 @@ void LangOptions::setLangDefaults(LangOptions &Opts, Language Lang,
   Opts.NamedLoops = Std.isC2y();
 
   Opts.HLSL = Lang == Language::HLSL;
-  if (Opts.HLSL && Opts.IncludeDefaultHeader)
-    Includes.push_back("hlsl.h");
+  if (Opts.HLSL) {
+    if (Opts.IncludeDefaultHeader)
+      Includes.push_back("hlsl.h");
+    // Set maximum matrix dimension to 4 for HLSL
+    Opts.MaxMatrixDimension = 4;
+  }
 
   // Set OpenCL Version.
   Opts.OpenCL = Std.isOpenCL();

clang/lib/Sema/HLSLExternalSemaSource.cpp

@@ -159,7 +159,8 @@ void HLSLExternalSemaSource::defineHLSLMatrixAlias() {
                                                   SourceLocation(), ColsParam));
   TemplateParams.emplace_back(ColsParam);
 
-  const unsigned MaxMatDim = 4;
+  const unsigned MaxMatDim = SemaPtr->getLangOpts().MaxMatrixDimension;
+  ;
   auto *MaxRow = IntegerLiteral::Create(
       AST, llvm::APInt(AST.getIntWidth(AST.IntTy), MaxMatDim), AST.IntTy,
       SourceLocation());

clang/lib/Sema/SemaChecking.cpp

@@ -16240,9 +16240,9 @@ getAndVerifyMatrixDimension(Expr *Expr, StringRef Name, Sema &S) {
     return {};
   }
   uint64_t Dim = Value->getZExtValue();
-  if (!ConstantMatrixType::isDimensionValid(Dim)) {
+  if (Dim == 0 || Dim > S.Context.getLangOpts().MaxMatrixDimension) {
     S.Diag(Expr->getBeginLoc(), diag::err_builtin_matrix_invalid_dimension)
-        << Name << ConstantMatrixType::getMaxElementsPerDimension();
+        << Name << S.Context.getLangOpts().MaxMatrixDimension;
     return {};
   }
   return Dim;

clang/lib/Sema/SemaType.cpp

@@ -2517,12 +2517,12 @@ QualType Sema::BuildMatrixType(QualType ElementTy, Expr *NumRows, Expr *NumCols,
     Diag(AttrLoc, diag::err_attribute_zero_size) << "matrix" << ColRange;
     return QualType();
   }
-  if (!ConstantMatrixType::isDimensionValid(MatrixRows)) {
+  if (MatrixRows > Context.getLangOpts().MaxMatrixDimension) {
     Diag(AttrLoc, diag::err_attribute_size_too_large)
         << RowRange << "matrix row";
     return QualType();
   }
-  if (!ConstantMatrixType::isDimensionValid(MatrixColumns)) {
+  if (MatrixColumns > Context.getLangOpts().MaxMatrixDimension) {
     Diag(AttrLoc, diag::err_attribute_size_too_large)
         << ColRange << "matrix column";
     return QualType();