[HLSL][Matrix] Constrain matrix_type sizes using concepts

[pow2clk]

HLSL matrices are limited to a maximum size of 4 in either dimension while the matrix extension allows for much larger sizes. Using concepts in the template declarations of the matrices similar to how resource types are being constrained in #116413 allows a language-specific limitation with friendly diagnostics.

[pow2clk]

The first part of this will be to consolidate some of the code in HLSLExternalSemaSource.cpp to better enable using concepts for the matrix templates from where they are currently implemented in code meant for the declaration of resource types.

That can be done once that change is in. Actually applying them to matrices will require the change allowing matrix types.

[damyanp]

@farzonl - I don't know how this issues fits in with what you're planning now. Feel free to close as not planned if you're tackling this some other way now. Or we can find the right parent for it.

[farzonl]

We actually already did this in https://github.com/llvm/llvm-project/pull/159446/files

Specifically this part:

llvm-project/clang/lib/Sema/HLSLExternalSemaSource.cpp

Lines 162 to 194 in dbffd0a

	const unsigned MaxMatDim = 4;
	auto *MaxRow = IntegerLiteral::Create(
	AST, llvm::APInt(AST.getIntWidth(AST.IntTy), MaxMatDim), AST.IntTy,
	SourceLocation());
	auto *MaxCol = IntegerLiteral::Create(
	AST, llvm::APInt(AST.getIntWidth(AST.IntTy), MaxMatDim), AST.IntTy,
	SourceLocation());
	auto *RowsRef = DeclRefExpr::Create(
	AST, NestedNameSpecifierLoc(), SourceLocation(), RowsParam,
	/*RefersToEnclosingVariableOrCapture*/ false,
	DeclarationNameInfo(RowsParam->getDeclName(), SourceLocation()),
	AST.IntTy, VK_LValue);
	auto *ColsRef = DeclRefExpr::Create(
	AST, NestedNameSpecifierLoc(), SourceLocation(), ColsParam,
	/*RefersToEnclosingVariableOrCapture*/ false,
	DeclarationNameInfo(ColsParam->getDeclName(), SourceLocation()),
	AST.IntTy, VK_LValue);
	auto *RowsLE = BinaryOperator::Create(AST, RowsRef, MaxRow, BO_LE, AST.BoolTy,
	VK_PRValue, OK_Ordinary,
	SourceLocation(), FPOptionsOverride());
	auto *ColsLE = BinaryOperator::Create(AST, ColsRef, MaxCol, BO_LE, AST.BoolTy,
	VK_PRValue, OK_Ordinary,
	SourceLocation(), FPOptionsOverride());
	auto *RequiresExpr = BinaryOperator::Create(
	AST, RowsLE, ColsLE, BO_LAnd, AST.BoolTy, VK_PRValue, OK_Ordinary,
	SourceLocation(), FPOptionsOverride());
	auto *ParamList = TemplateParameterList::Create(
	AST, SourceLocation(), SourceLocation(), TemplateParams, SourceLocation(),
	RequiresExpr);

That said there is still one way you can get a larger matrix via using matrix_type directly. To solve that we will need to implement #160190

Do we want to keep this ticket around to capture the need for matrix_type limits or should we close this because we are already using concepts to restrict matrix size in the template?

[damyanp]

Do we want to keep this ticket around to capture the need for matrix_type limits or should we close this because we are already using concepts to restrict matrix size in the template?

Up to you!