| 1 | #include "WebAssemblySortRegion.h" |
|---|---|
| 2 | #include "WebAssemblyExceptionInfo.h" |
| 3 | #include "llvm/CodeGen/MachineLoopInfo.h" |
| 4 | |
| 5 | using namespace llvm; |
| 6 | using namespace WebAssembly; |
| 7 | |
| 8 | namespace llvm { |
| 9 | namespace WebAssembly { |
| 10 | template <> |
| 11 | bool ConcreteSortRegion<MachineLoop>::isLoop() const { |
| 12 | return true; |
| 13 | } |
| 14 | } // end namespace WebAssembly |
| 15 | } // end namespace llvm |
| 16 | |
| 17 | const SortRegion *SortRegionInfo::getRegionFor(const MachineBasicBlock *MBB) { |
| 18 | const auto *ML = MLI.getLoopFor(BB: MBB); |
| 19 | const auto *WE = WEI.getExceptionFor(MBB); |
| 20 | if (!ML && !WE) |
| 21 | return nullptr; |
| 22 | // We determine subregion relationship by domination of their headers, i.e., |
| 23 | // if region A's header dominates region B's header, B is a subregion of A. |
| 24 | // WebAssemblyException contains BBs in all its subregions (loops or |
| 25 | // exceptions), but MachineLoop may not, because MachineLoop does not |
| 26 | // contain BBs that don't have a path to its header even if they are |
| 27 | // dominated by its header. So here we should use |
| 28 | // WE->contains(ML->getHeader()), but not ML->contains(WE->getHeader()). |
| 29 | if ((ML && !WE) || (ML && WE && WE->contains(MBB: ML->getHeader()))) { |
| 30 | // If the smallest region containing MBB is a loop |
| 31 | if (LoopMap.count(Val: ML)) |
| 32 | return LoopMap[ML].get(); |
| 33 | LoopMap[ML] = std::make_unique<ConcreteSortRegion<MachineLoop>>(args&: ML); |
| 34 | return LoopMap[ML].get(); |
| 35 | } else { |
| 36 | // If the smallest region containing MBB is an exception |
| 37 | if (ExceptionMap.count(Val: WE)) |
| 38 | return ExceptionMap[WE].get(); |
| 39 | ExceptionMap[WE] = |
| 40 | std::make_unique<ConcreteSortRegion<WebAssemblyException>>(args&: WE); |
| 41 | return ExceptionMap[WE].get(); |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | MachineBasicBlock *SortRegionInfo::getBottom(const SortRegion *R) { |
| 46 | if (R->isLoop()) |
| 47 | return getBottom(ML: MLI.getLoopFor(BB: R->getHeader())); |
| 48 | else |
| 49 | return getBottom(WE: WEI.getExceptionFor(MBB: R->getHeader())); |
| 50 | } |
| 51 | |
| 52 | MachineBasicBlock *SortRegionInfo::getBottom(const MachineLoop *ML) { |
| 53 | MachineBasicBlock *Bottom = ML->getHeader(); |
| 54 | for (MachineBasicBlock *MBB : ML->blocks()) { |
| 55 | if (MBB->getNumber() > Bottom->getNumber()) |
| 56 | Bottom = MBB; |
| 57 | // MachineLoop does not contain all BBs dominated by its header. BBs that |
| 58 | // don't have a path back to the loop header aren't included. But for the |
| 59 | // purpose of CFG sorting and stackification, we need a bottom BB among all |
| 60 | // BBs that are dominated by the loop header. So we check if there is any |
| 61 | // WebAssemblyException contained in this loop, and computes the most bottom |
| 62 | // BB of them all. |
| 63 | if (MBB->isEHPad()) { |
| 64 | MachineBasicBlock *ExBottom = getBottom(WE: WEI.getExceptionFor(MBB)); |
| 65 | if (ExBottom->getNumber() > Bottom->getNumber()) |
| 66 | Bottom = ExBottom; |
| 67 | } |
| 68 | } |
| 69 | return Bottom; |
| 70 | } |
| 71 | |
| 72 | MachineBasicBlock *SortRegionInfo::getBottom(const WebAssemblyException *WE) { |
| 73 | MachineBasicBlock *Bottom = WE->getHeader(); |
| 74 | for (MachineBasicBlock *MBB : WE->blocks()) |
| 75 | if (MBB->getNumber() > Bottom->getNumber()) |
| 76 | Bottom = MBB; |
| 77 | return Bottom; |
| 78 | } |
| 79 |