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Merged
merged 7 commits into from
Nov 25, 2025
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Merged

Fix typo of register -> registers crashes DXC with segfault #7729

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2bbd043
Register assignments with mismatching ': register()' syntax now doesn…
Nielsbishere Sep 3, 2025
9e78ab3
Clang format
Nielsbishere Sep 3, 2025
3d3574e
Merge branch 'main' of https://github.com/Microsoft/DirectXShaderComp…
Nielsbishere Nov 4, 2025
fdcc854
Added hlsl unit test to check if registers() crashes or produces the …
Nielsbishere Nov 4, 2025
5a0391d
Greatly simplified the invalid hlsl annotation check to allow it to w…
Nielsbishere Nov 5, 2025
f835f7b
Changed packofset to packoffsets and added one where it also uses inv…
Nielsbishere Nov 5, 2025
6cfc632
Fixed the error message
Nielsbishere Nov 19, 2025
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2 changes: 2 additions & 0 deletions tools/clang/include/clang/Basic/DiagnosticParseKinds.td
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Original file line number Diff line number Diff line change
Expand Up @@ -1025,6 +1025,8 @@ def warn_hlsl_effect_technique : Warning <
def warn_hlsl_semantic_identifier_collision : Warning <
"'%0' interpreted as semantic; previous definition(s) ignored">,
InGroup< HLSLSemanticIdentifierCollision >;
def err_hlsl_register_is_misspelled : Error <
"Syntax similar to : register() was used but unexpected keyword '%0' was used instead.">;
def err_hlsl_enum : Error<
"enum is unsupported in HLSL before 2017">;
def warn_hlsl_new_feature : Warning <
Expand Down
3 changes: 3 additions & 0 deletions tools/clang/include/clang/Parse/Parser.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2098,6 +2098,9 @@ class Parser : public CodeCompletionHandler {

// HLSL Change Starts: Parse HLSL Attributes and append them to Declarator Object
bool MaybeParseHLSLAttributes(std::vector<hlsl::UnusualAnnotation *> &target);
bool ConsumeRegisterAssignment(
hlsl::RegisterAssignment
&asg); // Make sure it starts with register( first
inline bool MaybeParseHLSLAttributes(Declarator &D) {
return MaybeParseHLSLAttributes(D.UnusualAnnotations);
}
Expand Down
271 changes: 152 additions & 119 deletions tools/clang/lib/Parse/ParseDecl.cpp
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Expand Up @@ -341,6 +341,143 @@ static void ParseSpaceForHLSL(const StringRef name,
}
}

bool Parser::ConsumeRegisterAssignment(hlsl::RegisterAssignment &r) {

ASTContext &context = getActions().getASTContext();

if (!Tok.is(tok::identifier)) {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}

StringRef identifierText = Tok.getIdentifierInfo()->getName();
if (IsShaderProfileLike(identifierText) ||
IsShaderProfileShort(identifierText)) {
r.ShaderProfile = Tok.getIdentifierInfo()->getName();
ConsumeToken(); // consume shader model
if (ExpectAndConsume(tok::comma, diag::err_expected)) {
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}
}

if (!Tok.is(tok::identifier)) {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}

DXASSERT(Tok.is(tok::identifier),
"otherwise previous code should have failed");
unsigned diagId;

bool hasOnlySpace = false;
identifierText = Tok.getIdentifierInfo()->getName();
if (identifierText.substr(0, sizeof("space") - 1).equals("space")) {
hasOnlySpace = true;
} else {
ParseRegisterNumberForHLSL(Tok.getIdentifierInfo()->getName(),
&r.RegisterType, &r.RegisterNumber, &diagId);
if (diagId == 0) {
r.setIsValid(true);
} else {
r.setIsValid(false);
Diag(Tok.getLocation(), diagId);
}

ConsumeToken(); // consume register (type'#')

ExprResult subcomponentResult;
if (Tok.is(tok::l_square)) {
BalancedDelimiterTracker brackets(*this, tok::l_square);
brackets.consumeOpen();

ExprResult result;
if (Tok.isNot(tok::r_square)) {
subcomponentResult = ParseConstantExpression();
r.IsValid = r.IsValid && !subcomponentResult.isInvalid();
Expr::EvalResult evalResult;
if (!subcomponentResult.get()->EvaluateAsRValue(evalResult, context) ||
evalResult.hasSideEffects() ||
(!evalResult.Val.isInt() && !evalResult.Val.isFloat())) {
Diag(Tok.getLocation(),
diag::err_hlsl_unsupported_register_noninteger);
r.setIsValid(false);
} else {
llvm::APSInt intResult;
if (evalResult.Val.isFloat()) {
bool isExact;
// TODO: consider what to do when convertToInteger fails
evalResult.Val.getFloat().convertToInteger(
intResult, llvm::APFloat::roundingMode::rmTowardZero, &isExact);
} else {
DXASSERT(
evalResult.Val.isInt(),
"otherwise prior test in this function should have failed");
intResult = evalResult.Val.getInt();
}

if (intResult.isNegative()) {
Diag(Tok.getLocation(),
diag::err_hlsl_unsupported_register_noninteger);
r.setIsValid(false);
} else {
r.RegisterOffset = intResult.getLimitedValue();
}
}
} else {
Diag(Tok.getLocation(), diag::err_expected_expression);
r.setIsValid(false);
}

if (brackets.consumeClose()) {
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}
}
}
if (hasOnlySpace) {
uint32_t RegisterSpaceValue = 0;
ParseSpaceForHLSL(Tok.getIdentifierInfo()->getName(), &RegisterSpaceValue,
&diagId);
if (diagId != 0) {
Diag(Tok.getLocation(), diagId);
r.setIsValid(false);
} else {
r.RegisterSpace = RegisterSpaceValue;
r.setIsValid(true);
}
ConsumeToken(); // consume identifier
} else {
if (Tok.is(tok::comma)) {
ConsumeToken(); // consume comma
if (!Tok.is(tok::identifier)) {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}
unsigned RegisterSpaceVal = 0;
ParseSpaceForHLSL(Tok.getIdentifierInfo()->getName(), &RegisterSpaceVal,
&diagId);
if (diagId != 0) {
Diag(Tok.getLocation(), diagId);
r.setIsValid(false);
} else {
r.RegisterSpace = RegisterSpaceVal;
}
ConsumeToken(); // consume identifier
}
}

if (ExpectAndConsume(tok::r_paren, diag::err_expected)) {
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}

return false;
}

bool Parser::MaybeParseHLSLAttributes(std::vector<hlsl::UnusualAnnotation *> &target)
{
if (!getLangOpts().HLSL) {
Expand Down Expand Up @@ -428,127 +565,9 @@ bool Parser::MaybeParseHLSLAttributes(std::vector<hlsl::UnusualAnnotation *> &ta
if (ExpectAndConsume(tok::l_paren, diag::err_expected_lparen_after, "register")) {
return true;
}
if (!Tok.is(tok::identifier)) {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}

StringRef identifierText = Tok.getIdentifierInfo()->getName();
if (IsShaderProfileLike(identifierText) || IsShaderProfileShort(identifierText)) {
r.ShaderProfile = Tok.getIdentifierInfo()->getName();
ConsumeToken(); // consume shader model
if (ExpectAndConsume(tok::comma, diag::err_expected)) {
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}
}

if (!Tok.is(tok::identifier)) {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}

DXASSERT(Tok.is(tok::identifier), "otherwise previous code should have failed");
unsigned diagId;

bool hasOnlySpace = false;
identifierText = Tok.getIdentifierInfo()->getName();
if (identifierText.substr(0, sizeof("space")-1).equals("space")) {
hasOnlySpace = true;
} else {
ParseRegisterNumberForHLSL(
Tok.getIdentifierInfo()->getName(), &r.RegisterType, &r.RegisterNumber, &diagId);
if (diagId == 0) {
r.setIsValid(true);
} else {
r.setIsValid(false);
Diag(Tok.getLocation(), diagId);
}

ConsumeToken(); // consume register (type'#')

ExprResult subcomponentResult;
if (Tok.is(tok::l_square)) {
BalancedDelimiterTracker brackets(*this, tok::l_square);
brackets.consumeOpen();

ExprResult result;
if (Tok.isNot(tok::r_square)) {
subcomponentResult = ParseConstantExpression();
r.IsValid = r.IsValid && !subcomponentResult.isInvalid();
Expr::EvalResult evalResult;
if (!subcomponentResult.get()->EvaluateAsRValue(evalResult, context) ||
evalResult.hasSideEffects() ||
(!evalResult.Val.isInt() && !evalResult.Val.isFloat())) {
Diag(Tok.getLocation(), diag::err_hlsl_unsupported_register_noninteger);
r.setIsValid(false);
} else {
llvm::APSInt intResult;
if (evalResult.Val.isFloat()) {
bool isExact;
// TODO: consider what to do when convertToInteger fails
evalResult.Val.getFloat().convertToInteger(intResult, llvm::APFloat::roundingMode::rmTowardZero, &isExact);
} else {
DXASSERT(evalResult.Val.isInt(), "otherwise prior test in this function should have failed");
intResult = evalResult.Val.getInt();
}

if (intResult.isNegative()) {
Diag(Tok.getLocation(), diag::err_hlsl_unsupported_register_noninteger);
r.setIsValid(false);
} else {
r.RegisterOffset = intResult.getLimitedValue();
}
}
} else {
Diag(Tok.getLocation(), diag::err_expected_expression);
r.setIsValid(false);
}

if (brackets.consumeClose()) {
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}
}
}
if (hasOnlySpace) {
uint32_t RegisterSpaceValue = 0;
ParseSpaceForHLSL(Tok.getIdentifierInfo()->getName(), &RegisterSpaceValue, &diagId);
if (diagId != 0) {
Diag(Tok.getLocation(), diagId);
r.setIsValid(false);
} else {
r.RegisterSpace = RegisterSpaceValue;
r.setIsValid(true);
}
ConsumeToken(); // consume identifier
} else {
if (Tok.is(tok::comma)) {
ConsumeToken(); // consume comma
if (!Tok.is(tok::identifier)) {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
return true;
}
unsigned RegisterSpaceVal = 0;
ParseSpaceForHLSL(Tok.getIdentifierInfo()->getName(), &RegisterSpaceVal, &diagId);
if (diagId != 0) {
Diag(Tok.getLocation(), diagId);
r.setIsValid(false);
}
else {
r.RegisterSpace = RegisterSpaceVal;
}
ConsumeToken(); // consume identifier
}
}

if (ExpectAndConsume(tok::r_paren, diag::err_expected)) {
SkipUntil(tok::r_paren, StopAtSemi); // skip through )
if (ConsumeRegisterAssignment(r))
return true;
}

target.push_back(new (context) hlsl::RegisterAssignment(r));
}
Expand Down Expand Up @@ -633,6 +652,20 @@ bool Parser::MaybeParseHLSLAttributes(std::vector<hlsl::UnusualAnnotation *> &ta
Actions.DiagnoseSemanticDecl(pUA);
ConsumeToken(); // consume semantic

// Likely a misspell of register() or a mismatching macro:
// registers() would cause a crash without this fix.

if (Tok.is(tok::l_paren)) {

Diag(Tok.getLocation(), diag::err_hlsl_register_is_misspelled)
<< semanticName;

ConsumeParen();
hlsl::RegisterAssignment dummy;
if (ConsumeRegisterAssignment(dummy)) // Skip invalid syntax
return true;
}

target.push_back(pUA);
}
else {
Expand Down
11 changes: 11 additions & 0 deletions tools/clang/test/SemaHLSL/register-mistype-errors.hlsl
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@@ -0,0 +1,11 @@
// RUN: %dxc -T lib_6_3 -verify %s

// expected-error@+1 {{Syntax similar to : register() was used but unexpected keyword 'registers' was used instead.}}
RWStructuredBuffer<float4> uav1 : registers(u3);
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@bob80905 bob80905 Nov 4, 2025

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Does this also work with : register (u3); ?

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@bob80905 bob80905 Nov 4, 2025

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Also would you be able to add a case for an incorrectly spelled pack offset?

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@Nielsbishere Nielsbishere Nov 5, 2025 •
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Wow I think you're correct there, I've never heard of that syntax before. Will fix it and add a test for it.
: register (u3) uses the same parsing as before (I only moved it), so that should still work. I can still add a test for it though.

The pack offset is pretty annoying, because from what I saw in #hlsl code horrors... I'll let the code speak for itself:

struct PSInput {
	float4 color : COLOR;
};

cbuffer test {
  Texture2D horrors : register(t0);  
};

float4 PSMain(PSInput input) : SV_TARGET {
	return input.color * horrors[0.xx];
}

So I can't automatically exclude this error when it's parsing a constant buffer. I guess the way would be to fallback to parsing that syntax (packoffset syntax) if it fails to be parsed as a register...

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Ah yes, HLSL horrors beyond comprehension.
I meant adding a test case for packoffset, not exactly sure what you mean by fix it.
You might consider making the error diagnostic more generic, like "unexpected identifier %s, expected an hlsl attribute " or something to that effect. That way if the packoffset parsing fails you can reuse the same error.
I'm not sure falling back would work either because we only attempt to parse the register if the next token is detected to be a register token.

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@Nielsbishere Nielsbishere Nov 5, 2025 •
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and... packoffset allows unions apparently.

cbuffer ohno {
  float a : packoffset(c0.x);
  float b : packoffset(c0.x);
};

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@Nielsbishere Nielsbishere Nov 5, 2025 •
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What I mean is that packoffset likely will get unintentionally parsed as register() as you suggested. I think I might be able to correctly identify it's misspelled packoffset as long as the rest of the syntax is similar.


[shader("pixel")]
float4 main(): SV_Target
{
uav1[0] = 2;
return 0.xxxx;
}