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Diffstat (limited to 'clang-tools-extra/clang-reorder-fields/Designator.cpp')
| -rw-r--r-- | clang-tools-extra/clang-reorder-fields/Designator.cpp | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/clang-tools-extra/clang-reorder-fields/Designator.cpp b/clang-tools-extra/clang-reorder-fields/Designator.cpp new file mode 100644 index 000000000000..d36a080c0435 --- /dev/null +++ b/clang-tools-extra/clang-reorder-fields/Designator.cpp @@ -0,0 +1,219 @@ +//===-- tools/extra/clang-reorder-fields/utils/Designator.cpp ---*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +/// +/// \file +/// This file contains the definition of the Designator and Designators utility +/// classes. +/// +//===----------------------------------------------------------------------===// + +#include "Designator.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/Expr.h" +#include "llvm/Support/raw_ostream.h" + +namespace clang { +namespace reorder_fields { + +void Designator::advanceToNextField() { + assert(!isFinished() && "Iterator is already finished"); + switch (Tag) { + case STRUCT: + if (StructIt.Record->isUnion()) { + // Union always finishes on first increment. + StructIt.Field = StructIt.Record->field_end(); + Type = QualType(); + break; + } + ++StructIt.Field; + if (StructIt.Field != StructIt.Record->field_end()) { + Type = StructIt.Field->getType(); + } else { + Type = QualType(); + } + break; + case ARRAY: + ++ArrayIt.Index; + break; + case ARRAY_RANGE: + ArrayIt.Index = ArrayRangeIt.End + 1; + ArrayIt.Size = ArrayRangeIt.Size; + Tag = ARRAY; + break; + } +} + +bool Designator::isFinished() { + switch (Tag) { + case STRUCT: + return StructIt.Field == StructIt.Record->field_end(); + case ARRAY: + return ArrayIt.Index == ArrayIt.Size; + case ARRAY_RANGE: + return ArrayRangeIt.End == ArrayRangeIt.Size; + } + return false; +} + +Designators::Designators(const Expr *Init, const InitListExpr *ILE, + const ASTContext *Context) + : Context(Context) { + if (ILE->getType()->isArrayType()) { + const ConstantArrayType *CAT = + Context->getAsConstantArrayType(ILE->getType()); + // Only constant size arrays are supported. + if (!CAT) { + DesignatorList.clear(); + return; + } + DesignatorList.push_back( + {CAT->getElementType(), 0, CAT->getSize().getZExtValue()}); + } else { + const RecordDecl *DesignatorRD = ILE->getType()->getAsRecordDecl(); + DesignatorList.push_back({DesignatorRD->field_begin()->getType(), + DesignatorRD->field_begin(), DesignatorRD}); + } + + // If the designator list is empty at this point, then there must be excess + // elements in the initializer list. They are not currently supported. + if (DesignatorList.empty()) + return; + + if (!enterImplicitInitLists(Init)) + DesignatorList.clear(); +} + +Designators::Designators(const DesignatedInitExpr *DIE, const InitListExpr *ILE, + const ASTContext *Context) + : Context(Context) { + for (const auto &D : DIE->designators()) { + if (D.isFieldDesignator()) { + RecordDecl *DesignatorRecord = D.getFieldDecl()->getParent(); + for (auto FieldIt = DesignatorRecord->field_begin(); + FieldIt != DesignatorRecord->field_end(); ++FieldIt) { + if (*FieldIt == D.getFieldDecl()) { + DesignatorList.push_back( + {FieldIt->getType(), FieldIt, DesignatorRecord}); + break; + } + } + } else { + const QualType CurrentType = DesignatorList.empty() + ? ILE->getType() + : DesignatorList.back().getType(); + const ConstantArrayType *CAT = + Context->getAsConstantArrayType(CurrentType); + if (!CAT) { + // Non-constant-sized arrays are not supported. + DesignatorList.clear(); + return; + } + if (D.isArrayDesignator()) { + DesignatorList.push_back({CAT->getElementType(), + DIE->getArrayIndex(D) + ->EvaluateKnownConstInt(*Context) + .getZExtValue(), + CAT->getSize().getZExtValue()}); + } else if (D.isArrayRangeDesignator()) { + DesignatorList.push_back({CAT->getElementType(), + DIE->getArrayRangeStart(D) + ->EvaluateKnownConstInt(*Context) + .getZExtValue(), + DIE->getArrayRangeEnd(D) + ->EvaluateKnownConstInt(*Context) + .getZExtValue(), + CAT->getSize().getZExtValue()}); + } else { + llvm_unreachable("Unexpected designator kind"); + } + } + } +} + +bool Designators::advanceToNextField(const Expr *Init) { + // Remove all designators that refer to the last field of a struct or final + // element of the array. + while (!DesignatorList.empty()) { + auto &CurrentDesignator = DesignatorList.back(); + CurrentDesignator.advanceToNextField(); + if (CurrentDesignator.isFinished()) { + DesignatorList.pop_back(); + continue; + } + break; + } + + // If the designator list is empty at this point, then there must be excess + // elements in the initializer list. They are not currently supported. + if (DesignatorList.empty()) + return false; + + if (!enterImplicitInitLists(Init)) { + DesignatorList.clear(); + return false; + } + + return true; +} + +bool Designators::enterImplicitInitLists(const Expr *Init) { + // Check for missing braces by comparing the type of the last designator and + // type of Init. + while (true) { + const QualType T = DesignatorList.back().getType(); + // If the types match, there are no missing braces. + if (Init->getType() == T) + break; + + // If the current type is a struct, then get its first field. + if (T->isRecordType()) { + DesignatorList.push_back({T->getAsRecordDecl()->field_begin()->getType(), + T->getAsRecordDecl()->field_begin(), + T->getAsRecordDecl()}); + continue; + } + // If the current type is an array, then get its first element. + if (T->isArrayType()) { + DesignatorList.push_back( + {Context->getAsArrayType(T)->getElementType(), 0, + Context->getAsConstantArrayType(T)->getSize().getZExtValue()}); + continue; + } + + // The initializer doesn't match the expected type. The initializer list is + // invalid. + return false; + } + + return true; +} + +std::string Designators::toString() const { + if (DesignatorList.empty()) + return ""; + std::string Designator; + llvm::raw_string_ostream OS(Designator); + for (auto &I : DesignatorList) { + switch (I.getTag()) { + case Designator::STRUCT: + OS << '.' << I.getStructIter()->getName(); + break; + case Designator::ARRAY: + OS << '[' << I.getArrayIndex() << ']'; + break; + case Designator::ARRAY_RANGE: + OS << '[' << I.getArrayRangeStart() << "..." << I.getArrayRangeEnd() + << ']'; + } + } + OS << " = "; + return Designator; +} + +} // namespace reorder_fields +} // namespace clang |