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(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(ML->getHeader()))) { 30 // If the smallest region containing MBB is a loop 31 if (LoopMap.count(ML)) 32 return LoopMap[ML].get(); 33 LoopMap[ML] = std::make_unique<ConcreteSortRegion<MachineLoop>>(ML); 34 return LoopMap[ML].get(); 35 } else { 36 // If the smallest region containing MBB is an exception 37 if (ExceptionMap.count(WE)) 38 return ExceptionMap[WE].get(); 39 ExceptionMap[WE] = 40 std::make_unique<ConcreteSortRegion<WebAssemblyException>>(WE); 41 return ExceptionMap[WE].get(); 42 } 43 } 44 45 MachineBasicBlock *SortRegionInfo::getBottom(const SortRegion *R) { 46 if (R->isLoop()) 47 return getBottom(MLI.getLoopFor(R->getHeader())); 48 else 49 return getBottom(WEI.getExceptionFor(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(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