18 using Field = OptimizedStructLayoutField;  typedef
21 static void checkValidLayout(ArrayRef<Field> Fields, uint64_t Size,  in checkValidLayout()
25   for (auto &Field : Fields) {  in checkValidLayout()  local
26     assert(Field.hasFixedOffset() &&  in checkValidLayout()
27            "didn't assign a fixed offset to field");  in checkValidLayout()
28     assert(isAligned(Field.Alignment, Field.Offset) &&  in checkValidLayout()
29            "didn't assign a correctly-aligned offset to field");  in checkValidLayout()
30     assert(Field.Offset >= LastEnd &&  in checkValidLayout()
32     LastEnd = Field.getEndOffset();  in checkValidLayout()
33     assert(Field.Alignment <= MaxAlign &&  in checkValidLayout()
35     ComputedMaxAlign = std::max(Field.Alignment, MaxAlign);  in checkValidLayout()
43 llvm::performOptimizedStructLayout(MutableArrayRef<Field> Fields) {  in performOptimizedStructLayout()
49     for (auto &Field : Fields) {  in performOptimizedStructLayout()  local
50       assert(Field.Size > 0 && "field of zero size");  in performOptimizedStructLayout()
51       if (Field.hasFixedOffset()) {  in performOptimizedStructLayout()
54         assert(LastEnd <= Field.Offset &&  in performOptimizedStructLayout()
56         LastEnd = Field.getEndOffset();  in performOptimizedStructLayout()
57         assert(LastEnd > Field.Offset &&  in performOptimizedStructLayout()
69   // Find the first flexible-offset field, tracking MaxAlign.  in performOptimizedStructLayout()
107                  [](const Field *lhs, const Field *rhs) -> int {  in performOptimizedStructLayout()
175   // field before the gap, or 0 if the gap is at the beginning of the  in performOptimizedStructLayout()
176   // structure.  Find the "best" flexible-offset field according to the  in performOptimizedStructLayout()
177   // criteria below.  If no such field exists, proceed to the next gap.  in performOptimizedStructLayout()
178   // Otherwise, add the field at the first properly-aligned offset for  in performOptimizedStructLayout()
179   // that field that is >= LastEnd, then update LastEnd and repeat in  in performOptimizedStructLayout()
180   // order to fill any remaining gap following that field.  in performOptimizedStructLayout()
183   // last fixed-offset field, or 0 if there are no fixed-offset fields.  in performOptimizedStructLayout()
185   // flexible-offset field according to the criteria below, add it at  in performOptimizedStructLayout()
186   // the first properly-aligned offset for that field that is >= LastEnd,  in performOptimizedStructLayout()
187   // and update LastEnd to the first byte following the field.  in performOptimizedStructLayout()
189   // The "best" field is chosen by the following criteria, considered  in performOptimizedStructLayout()
192   // - When filling a gap betweeen fields, the field must fit.  in performOptimizedStructLayout()
193   // - A field is preferred if it requires less padding following LastEnd.  in performOptimizedStructLayout()
194   // - A field is preferred if it is more aligned.  in performOptimizedStructLayout()
195   // - A field is preferred if it is larger.  in performOptimizedStructLayout()
196   // - A field is preferred if it appeared earlier in the initial order.  in performOptimizedStructLayout()
216   // the last fixed-layout field, the objects fit in the bins; note that  in performOptimizedStructLayout()
250     static Field *getNext(Field *Cur) {  in performOptimizedStructLayout()
251       return static_cast<Field *>(Cur->Scratch);  in performOptimizedStructLayout()
285         assert(I->Alignment == Queue.Alignment && "bad field in queue");  in performOptimizedStructLayout()
294   /// Helper function to remove a field from a queue.  in performOptimizedStructLayout()
295   auto spliceFromQueue = [&](AlignmentQueue *Queue, Field *Last, Field *Cur) {  in performOptimizedStructLayout()
303       // If Cur was the last field in the list, we need to update MinSize.  in performOptimizedStructLayout()
304       // We can just use the last field's size because the list is in  in performOptimizedStructLayout()
322   SmallVector<Field, 16> Layout;  in performOptimizedStructLayout()
330   auto addToLayout = [&](AlignmentQueue *Queue, Field *Last, Field *Cur,  in performOptimizedStructLayout()
346   // Helper function to try to find a field in the given queue that'll  in performOptimizedStructLayout()
355     // Figure out the maximum size that a field can be, and ignore this  in performOptimizedStructLayout()
362     // Find the matching field.  Note that this should always find  in performOptimizedStructLayout()
364     for (Field *Cur = Queue->Head, *Last = nullptr; true;  in performOptimizedStructLayout()
374   // Helper function to find the "best" flexible-offset field according  in performOptimizedStructLayout()
395       // satisfactory field.  in performOptimizedStructLayout()
422   // flexible-offset field that fits.  in performOptimizedStructLayout()
437   // Phase 2: repeatedly add the best flexible-offset field until  in performOptimizedStructLayout()
441     assert(Success && "didn't find a field with no fixed limit?");  in performOptimizedStructLayout()