|
| 1 | +//===-- tools/extra/clang-reorder-fields/utils/Designator.cpp ---*- C++ -*-===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | +/// |
| 9 | +/// \file |
| 10 | +/// This file contains the definition of the Designator and Designators utility |
| 11 | +/// classes. |
| 12 | +/// |
| 13 | +//===----------------------------------------------------------------------===// |
| 14 | + |
| 15 | +#include "Designator.h" |
| 16 | +#include "clang/AST/ASTContext.h" |
| 17 | +#include "clang/AST/Expr.h" |
| 18 | +#include "llvm/Support/raw_ostream.h" |
| 19 | + |
| 20 | +namespace clang { |
| 21 | +namespace reorder_fields { |
| 22 | + |
| 23 | +void Designator::advanceToNextField() { |
| 24 | + assert(!isFinished() && "Iterator is already finished"); |
| 25 | + switch (Tag) { |
| 26 | + case STRUCT: |
| 27 | + if (StructIt.Record->isUnion()) { |
| 28 | + // Union always finishes on first increment. |
| 29 | + StructIt.Field = StructIt.Record->field_end(); |
| 30 | + Type = QualType(); |
| 31 | + break; |
| 32 | + } |
| 33 | + ++StructIt.Field; |
| 34 | + if (StructIt.Field != StructIt.Record->field_end()) { |
| 35 | + Type = StructIt.Field->getType(); |
| 36 | + } else { |
| 37 | + Type = QualType(); |
| 38 | + } |
| 39 | + break; |
| 40 | + case ARRAY: |
| 41 | + ++ArrayIt.Index; |
| 42 | + break; |
| 43 | + case ARRAY_RANGE: |
| 44 | + ArrayIt.Index = ArrayRangeIt.End + 1; |
| 45 | + ArrayIt.Size = ArrayRangeIt.Size; |
| 46 | + Tag = ARRAY; |
| 47 | + break; |
| 48 | + } |
| 49 | +} |
| 50 | + |
| 51 | +bool Designator::isFinished() { |
| 52 | + switch (Tag) { |
| 53 | + case STRUCT: |
| 54 | + return StructIt.Field == StructIt.Record->field_end(); |
| 55 | + case ARRAY: |
| 56 | + return ArrayIt.Index == ArrayIt.Size; |
| 57 | + case ARRAY_RANGE: |
| 58 | + return ArrayRangeIt.End == ArrayRangeIt.Size; |
| 59 | + } |
| 60 | + return false; |
| 61 | +} |
| 62 | + |
| 63 | +Designators::Designators(const Expr *Init, const InitListExpr *ILE, |
| 64 | + const ASTContext *Context) |
| 65 | + : Context(Context) { |
| 66 | + if (ILE->getType()->isArrayType()) { |
| 67 | + const ConstantArrayType *CAT = |
| 68 | + Context->getAsConstantArrayType(ILE->getType()); |
| 69 | + // Only constant size arrays are supported. |
| 70 | + if (!CAT) { |
| 71 | + DesignatorList.clear(); |
| 72 | + return; |
| 73 | + } |
| 74 | + DesignatorList.push_back( |
| 75 | + {CAT->getElementType(), 0, CAT->getSize().getZExtValue()}); |
| 76 | + } else { |
| 77 | + const RecordDecl *DesignatorRD = ILE->getType()->getAsRecordDecl(); |
| 78 | + DesignatorList.push_back({DesignatorRD->field_begin()->getType(), |
| 79 | + DesignatorRD->field_begin(), DesignatorRD}); |
| 80 | + } |
| 81 | + |
| 82 | + // If the designator list is empty at this point, then there must be excess |
| 83 | + // elements in the initializer list. They are not currently supported. |
| 84 | + if (DesignatorList.empty()) |
| 85 | + return; |
| 86 | + |
| 87 | + if (!enterImplicitInitLists(Init)) |
| 88 | + DesignatorList.clear(); |
| 89 | +} |
| 90 | + |
| 91 | +Designators::Designators(const DesignatedInitExpr *DIE, const InitListExpr *ILE, |
| 92 | + const ASTContext *Context) |
| 93 | + : Context(Context) { |
| 94 | + for (const auto &D : DIE->designators()) { |
| 95 | + if (D.isFieldDesignator()) { |
| 96 | + RecordDecl *DesignatorRecord = D.getFieldDecl()->getParent(); |
| 97 | + for (auto FieldIt = DesignatorRecord->field_begin(); |
| 98 | + FieldIt != DesignatorRecord->field_end(); ++FieldIt) { |
| 99 | + if (*FieldIt == D.getFieldDecl()) { |
| 100 | + DesignatorList.push_back( |
| 101 | + {FieldIt->getType(), FieldIt, DesignatorRecord}); |
| 102 | + break; |
| 103 | + } |
| 104 | + } |
| 105 | + } else { |
| 106 | + const QualType CurrentType = DesignatorList.empty() |
| 107 | + ? ILE->getType() |
| 108 | + : DesignatorList.back().getType(); |
| 109 | + const ConstantArrayType *CAT = |
| 110 | + Context->getAsConstantArrayType(CurrentType); |
| 111 | + if (!CAT) { |
| 112 | + // Non-constant-sized arrays are not supported. |
| 113 | + DesignatorList.clear(); |
| 114 | + return; |
| 115 | + } |
| 116 | + if (D.isArrayDesignator()) { |
| 117 | + DesignatorList.push_back({CAT->getElementType(), |
| 118 | + DIE->getArrayIndex(D) |
| 119 | + ->EvaluateKnownConstInt(*Context) |
| 120 | + .getZExtValue(), |
| 121 | + CAT->getSize().getZExtValue()}); |
| 122 | + } else if (D.isArrayRangeDesignator()) { |
| 123 | + DesignatorList.push_back({CAT->getElementType(), |
| 124 | + DIE->getArrayRangeStart(D) |
| 125 | + ->EvaluateKnownConstInt(*Context) |
| 126 | + .getZExtValue(), |
| 127 | + DIE->getArrayRangeEnd(D) |
| 128 | + ->EvaluateKnownConstInt(*Context) |
| 129 | + .getZExtValue(), |
| 130 | + CAT->getSize().getZExtValue()}); |
| 131 | + } else { |
| 132 | + llvm_unreachable("Unexpected designator kind"); |
| 133 | + } |
| 134 | + } |
| 135 | + } |
| 136 | +} |
| 137 | + |
| 138 | +bool Designators::advanceToNextField(const Expr *Init) { |
| 139 | + // Remove all designators that refer to the last field of a struct or final |
| 140 | + // element of the array. |
| 141 | + while (!DesignatorList.empty()) { |
| 142 | + auto &CurrentDesignator = DesignatorList.back(); |
| 143 | + CurrentDesignator.advanceToNextField(); |
| 144 | + if (CurrentDesignator.isFinished()) { |
| 145 | + DesignatorList.pop_back(); |
| 146 | + continue; |
| 147 | + } |
| 148 | + break; |
| 149 | + } |
| 150 | + |
| 151 | + // If the designator list is empty at this point, then there must be excess |
| 152 | + // elements in the initializer list. They are not currently supported. |
| 153 | + if (DesignatorList.empty()) |
| 154 | + return false; |
| 155 | + |
| 156 | + if (!enterImplicitInitLists(Init)) { |
| 157 | + DesignatorList.clear(); |
| 158 | + return false; |
| 159 | + } |
| 160 | + |
| 161 | + return true; |
| 162 | +} |
| 163 | + |
| 164 | +bool Designators::enterImplicitInitLists(const Expr *Init) { |
| 165 | + // Check for missing braces by comparing the type of the last designator and |
| 166 | + // type of Init. |
| 167 | + while (true) { |
| 168 | + const QualType T = DesignatorList.back().getType(); |
| 169 | + // If the types match, there are no missing braces. |
| 170 | + if (Init->getType() == T) |
| 171 | + break; |
| 172 | + |
| 173 | + // If the current type is a struct, then get its first field. |
| 174 | + if (T->isRecordType()) { |
| 175 | + DesignatorList.push_back({T->getAsRecordDecl()->field_begin()->getType(), |
| 176 | + T->getAsRecordDecl()->field_begin(), |
| 177 | + T->getAsRecordDecl()}); |
| 178 | + continue; |
| 179 | + } |
| 180 | + // If the current type is an array, then get its first element. |
| 181 | + if (T->isArrayType()) { |
| 182 | + DesignatorList.push_back( |
| 183 | + {Context->getAsArrayType(T)->getElementType(), 0, |
| 184 | + Context->getAsConstantArrayType(T)->getSize().getZExtValue()}); |
| 185 | + continue; |
| 186 | + } |
| 187 | + |
| 188 | + // The initializer doesn't match the expected type. The initializer list is |
| 189 | + // invalid. |
| 190 | + return false; |
| 191 | + } |
| 192 | + |
| 193 | + return true; |
| 194 | +} |
| 195 | + |
| 196 | +std::string Designators::toString() const { |
| 197 | + if (DesignatorList.empty()) |
| 198 | + return ""; |
| 199 | + std::string Designator; |
| 200 | + llvm::raw_string_ostream OS(Designator); |
| 201 | + for (auto &I : DesignatorList) { |
| 202 | + switch (I.getTag()) { |
| 203 | + case Designator::STRUCT: |
| 204 | + OS << '.' << I.getStructIter()->getName(); |
| 205 | + break; |
| 206 | + case Designator::ARRAY: |
| 207 | + OS << '[' << I.getArrayIndex() << ']'; |
| 208 | + break; |
| 209 | + case Designator::ARRAY_RANGE: |
| 210 | + OS << '[' << I.getArrayRangeStart() << "..." << I.getArrayRangeEnd() |
| 211 | + << ']'; |
| 212 | + } |
| 213 | + } |
| 214 | + OS << " = "; |
| 215 | + return Designator; |
| 216 | +} |
| 217 | + |
| 218 | +} // namespace reorder_fields |
| 219 | +} // namespace clang |
0 commit comments