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[Matrix][Clang][HLSL] Move MaxMatrixDimension to a LangOpt #163307

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Merged
merged 5 commits into from
Oct 16, 2025
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[Matrix][Clang][HLSL] Move MaxMatrixDimension to a LangOpt #163307

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f709052
[NFC][Matrix][Clang][HLSL] Move MaxMatrixDimension to a LangOpt
farzonl Oct 14, 2025
17751d0
add unit test
farzonl Oct 14, 2025
1d1ff45
update tests to confirm matrix_type can not be larger than 4 per dim
farzonl Oct 15, 2025
98a61b2
add more tests and cover the row and column size too large case with …
farzonl Oct 15, 2025
74c9738
fix typo
farzonl Oct 16, 2025
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12 changes: 0 additions & 12 deletions clang/include/clang/AST/TypeBase.h
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Expand Up @@ -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);

Expand All @@ -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());
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1 change: 1 addition & 0 deletions clang/include/clang/Basic/LangOptions.def
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Expand Up @@ -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")

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4 changes: 2 additions & 2 deletions clang/lib/AST/ASTContext.cpp
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Expand Up @@ -4712,8 +4712,8 @@ 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))
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8 changes: 6 additions & 2 deletions clang/lib/Basic/LangOptions.cpp
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Expand Up @@ -132,8 +132,12 @@ 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();
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3 changes: 2 additions & 1 deletion clang/lib/Sema/HLSLExternalSemaSource.cpp
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Expand Up @@ -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());
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4 changes: 2 additions & 2 deletions clang/lib/Sema/SemaChecking.cpp
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Expand Up @@ -16239,9 +16239,9 @@ 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;
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10 changes: 8 additions & 2 deletions clang/lib/Sema/SemaType.cpp
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Expand Up @@ -2517,12 +2517,18 @@ 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 &&
MatrixColumns > Context.getLangOpts().MaxMatrixDimension) {
Diag(AttrLoc, diag::err_attribute_size_too_large)
<< RowRange << ColRange << "matrix row and column";
return QualType();
}
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();
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1 change: 1 addition & 0 deletions clang/test/SemaCXX/matrix-type.cpp
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Expand Up @@ -14,6 +14,7 @@ void matrix_var_dimensions(int Rows, unsigned Columns, char C) {
using matrix7_t = int __attribute__((matrix_type(1, 0))); // expected-error{{zero matrix size}}
using matrix7_t = int __attribute__((matrix_type(char, 0))); // expected-error{{expected '(' for function-style cast or type construction}}
using matrix8_t = int __attribute__((matrix_type(1048576, 1))); // expected-error{{matrix row size too large}}
using matrix8_t = int __attribute__((matrix_type(1048576, 1048576))); // expected-error{{matrix row and column size too large}}
}

struct S1 {};
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23 changes: 23 additions & 0 deletions clang/test/SemaHLSL/BuiltIns/matrix-basic_types-errors.hlsl
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Expand Up @@ -10,3 +10,26 @@ uint16_t4x4 mat2;
matrix<int, 5, 5> mat3;
// expected-error@-1 {{constraints not satisfied for alias template 'matrix' [with element = int, rows_count = 5, cols_count = 5]}}
// expected-note@* {{because '5 <= 4' (5 <= 4) evaluated to false}}

using float8x4 = __attribute__((matrix_type(8,4))) float;
// expected-error@-1 {{matrix row size too large}}

using float4x8 = __attribute__((matrix_type(4,8))) float;
// expected-error@-1 {{matrix column size too large}}
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A few other cases to consider:

using float8x8 = __attribute__((matrix_type(8,8))) float; // both dimensions too large

// these are likely tested in C/C++, but might be worth verifying or just adding them:
using floatNeg1x4 = __attribute__((matrix_type(-1,4))) float; // negative rows
using float4xNeg1 = __attribute__((matrix_type(4,-1))) float; // negative columns
using floatNeg1xNeg1 = __attribute__((matrix_type(-1,-1))) float; // both dimensions negative!

using float0x4 = __attribute__((matrix_type(0,4))) float; // zero rows?
using float4x0 = __attribute__((matrix_type(4,0))) float; // zero columns?
using float0x0 = __attribute__((matrix_type(0,0))) float; // both dimensions zero

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The current implementation does not do multiple errors so if both row/col are larger than 4 then we will just error matrix row size too large. The negative cases will just be treated as an unsinged integer so 4294967295 and will also be a row dimensions too large case. All of these will error.

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I can change the BuildMatrixType implementation to allow for both row and col errors.


using float8x8 = __attribute__((matrix_type(8,8))) float;
// expected-error@-1 {{matrix row and column size too large}}

using floatNeg1x4 = __attribute__((matrix_type(-1,4))) float;
// expected-error@-1 {{matrix row size too large}}
using float4xNeg1 = __attribute__((matrix_type(4,-1))) float;
// expected-error@-1 {{matrix column size too large}}
using floatNeg1xNeg1 = __attribute__((matrix_type(-1,-1))) float;
// expected-error@-1 {{matrix row and column size too large}}

using float0x4 = __attribute__((matrix_type(0,4))) float;
// expected-error@-1 {{zero matrix size}}
using float4x0 = __attribute__((matrix_type(4,0))) float;
// expected-error@-1 {{zero matrix size}}
using float0x0 = __attribute__((matrix_type(0,0))) float;
// expected-error@-1 {{zero matrix size}}
20 changes: 20 additions & 0 deletions clang/unittests/Frontend/CompilerInvocationTest.cpp
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Expand Up @@ -732,6 +732,26 @@ TEST_F(CommandLineTest, ConditionalParsingIfTrueFlagPresent) {
ASSERT_THAT(GeneratedArgs, Contains(StrEq("-sycl-std=2017")));
}

TEST_F(CommandLineTest, ConditionalParsingIfHLSLFlagPresent) {
const char *Args[] = {"-xhlsl"};

CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);

ASSERT_EQ(Invocation.getLangOpts().MaxMatrixDimension, 4u);

Invocation.generateCC1CommandLine(GeneratedArgs, *this);
}

TEST_F(CommandLineTest, ConditionalParsingIfHLSLFlagNotPresent) {
const char *Args[] = {""};

CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);

ASSERT_EQ(Invocation.getLangOpts().MaxMatrixDimension, 1048575u);

Invocation.generateCC1CommandLine(GeneratedArgs, *this);
}

// Wide integer option.

TEST_F(CommandLineTest, WideIntegerHighValue) {
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