[clang] [HLSL] Add __is_scalarized_layout_compatible (PR #102227)
Damyan Pepper via cfe-commits
cfe-commits at lists.llvm.org
Tue Aug 13 14:35:41 PDT 2024
================
@@ -1142,3 +1142,85 @@ bool SemaHLSL::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
}
return false;
}
+
+static void BuildFlattenedTypeList(QualType BaseTy,
+ llvm::SmallVectorImpl<QualType> &List) {
+ llvm::SmallVector<QualType, 16> WorkList;
+ WorkList.push_back(BaseTy);
+ while (!WorkList.empty()) {
+ QualType T = WorkList.pop_back_val();
+ T = T.getCanonicalType().getUnqualifiedType();
+ assert(!isa<MatrixType>(T) && "Matrix types not yet supported in HLSL");
+ if (const auto *AT = dyn_cast<ConstantArrayType>(T)) {
+ llvm::SmallVector<QualType, 16> ElementFields;
+ // Generally I've avoided recursion in this algorithm, but arrays of
+ // structs could be time-consuming to flatten and churn through on the
+ // work list. Hopefully nesting arrays of structs containing arrays
+ // of structs too many levels deep is unlikely.
+ BuildFlattenedTypeList(AT->getElementType(), ElementFields);
+ // Repeat the element's field list n times.
+ for (uint64_t Ct = 0; Ct < AT->getZExtSize(); ++Ct)
+ List.insert(List.end(), ElementFields.begin(), ElementFields.end());
+ continue;
+ }
+ // Vectors can only have element types that are builtin types, so this can
+ // add directly to the list instead of to the WorkList.
+ if (const auto *VT = dyn_cast<VectorType>(T)) {
+ List.insert(List.end(), VT->getNumElements(), VT->getElementType());
+ continue;
+ }
+ if (const auto *RT = dyn_cast<RecordType>(T)) {
+ const RecordDecl *RD = RT->getDecl();
+ if (RD->isUnion()) {
+ List.push_back(T);
+ continue;
+ }
+ const CXXRecordDecl *CXXD = dyn_cast<CXXRecordDecl>(RD);
+
+ llvm::SmallVector<QualType, 16> FieldTypes;
+ if (CXXD && CXXD->isStandardLayout())
+ RD = CXXD->getStandardLayoutBaseWithFields();
+
+ for (const auto *FD : RD->fields())
+ FieldTypes.push_back(FD->getType());
+ // Reverse the newly added sub-range.
+ std::reverse(FieldTypes.begin(), FieldTypes.end());
----------------
damyanp wrote:
Is it obvious to someone with more domain knowledge why this has to be reversed?
https://github.com/llvm/llvm-project/pull/102227
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