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[HLSL][NFC] Move packoffset validation to separate function and calculate offsets in bytes (#121989)

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There will be more changes coming in to `SemaHLSL::ActOnFinishBuffer` so
it would be good to move the packoffset validation out to a separate
function. This change also unifies the units for cbuffer offset
calculations to bytes.
This commit is contained in:
Helena Kotas 2025-01-09 11:01:44 -08:00 committed by GitHub
parent ca10deaa72
commit c123d0c1df
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GPG Key ID: B5690EEEBB952194
2 changed files with 47 additions and 35 deletions
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6
clang/include/clang/Basic/Attr.td
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@ -4711,9 +4711,9 @@ def HLSLPackOffset: HLSLAnnotationAttr {
let Args = [IntArgument<"Subcomponent">, IntArgument<"Component">];
let Documentation = [HLSLPackOffsetDocs];
let AdditionalMembers = [{
unsigned getOffset() {
return subcomponent * 4 + component;
}
unsigned getOffsetInBytes() {
return subcomponent * 16 + component * 4;
}
}];
}

76
clang/lib/Sema/SemaHLSL.cpp
View File

@ -164,18 +164,20 @@ Decl *SemaHLSL::ActOnStartBuffer(Scope *BufferScope, bool CBuffer,
return Result;
}
// Calculate the size of a legacy cbuffer type based on
// Calculate the size of a legacy cbuffer type in bytes 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;
constexpr unsigned CBufferAlign = 16;
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;
// FIXME: This is not the correct alignment, it does not work for 16-bit
// types. See llvm/llvm-project#119641.
unsigned FieldAlign = 4;
if (Ty->isAggregateType())
FieldAlign = CBufferAlign;
Size = llvm::alignTo(Size, FieldAlign);
@ -194,17 +196,19 @@ static unsigned calculateLegacyCbufferSize(const ASTContext &Context,
calculateLegacyCbufferSize(Context, VT->getElementType());
Size = ElementSize * ElementCount;
} else {
Size = Context.getTypeSize(T);
Size = Context.getTypeSize(T) / 8;
}
return Size;
}
void SemaHLSL::ActOnFinishBuffer(Decl *Dcl, SourceLocation RBrace) {
auto *BufDecl = cast<HLSLBufferDecl>(Dcl);
BufDecl->setRBraceLoc(RBrace);
// Validate packoffset.
// Validate packoffset:
// - if packoffset it used it must be set on all declarations inside the buffer
// - packoffset ranges must not overlap
static void validatePackoffset(Sema &S, HLSLBufferDecl *BufDecl) {
llvm::SmallVector<std::pair<VarDecl *, HLSLPackOffsetAttr *>> PackOffsetVec;
// Make sure the packoffset annotations are either on all declarations
// or on none.
bool HasPackOffset = false;
bool HasNonPackOffset = false;
for (auto *Field : BufDecl->decls()) {
@ -219,33 +223,41 @@ void SemaHLSL::ActOnFinishBuffer(Decl *Dcl, SourceLocation RBrace) {
}
}
if (HasPackOffset && HasNonPackOffset)
Diag(BufDecl->getLocation(), diag::warn_hlsl_packoffset_mix);
if (!HasPackOffset)
return;
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();
});
if (HasNonPackOffset)
S.Diag(BufDecl->getLocation(), diag::warn_hlsl_packoffset_mix);
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;
}
// Make sure there is no overlap in packoffset - sort PackOffsetVec by offset
// and compare adjacent values.
ASTContext &Context = S.getASTContext();
std::sort(PackOffsetVec.begin(), PackOffsetVec.end(),
[](const std::pair<VarDecl *, HLSLPackOffsetAttr *> &LHS,
const std::pair<VarDecl *, HLSLPackOffsetAttr *> &RHS) {
return LHS.second->getOffsetInBytes() <
RHS.second->getOffsetInBytes();
});
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->getOffsetInBytes();
unsigned End = Begin + Size;
unsigned NextBegin = PackOffsetVec[i + 1].second->getOffsetInBytes();
if (End > NextBegin) {
VarDecl *NextVar = PackOffsetVec[i + 1].first;
S.Diag(NextVar->getLocation(), diag::err_hlsl_packoffset_overlap)
<< NextVar << Var;
}
}
}
void SemaHLSL::ActOnFinishBuffer(Decl *Dcl, SourceLocation RBrace) {
auto *BufDecl = cast<HLSLBufferDecl>(Dcl);
BufDecl->setRBraceLoc(RBrace);
validatePackoffset(SemaRef, BufDecl);
SemaRef.PopDeclContext();
}