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#include "WebAssemblySortRegion.h"
#include "WebAssemblyExceptionInfo.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
using namespace llvm;
using namespace WebAssembly;
namespace llvm {
namespace WebAssembly {
template <>
bool ConcreteSortRegion<MachineLoop>::isLoop() const {
return true;
}
} // end namespace WebAssembly
} // end namespace llvm
const SortRegion *SortRegionInfo::getRegionFor(const MachineBasicBlock *MBB) {
const auto *ML = MLI.getLoopFor(MBB);
const auto *WE = WEI.getExceptionFor(MBB);
if (!ML && !WE)
return nullptr;
// We determine subregion relationship by domination of their headers, i.e.,
// if region A's header dominates region B's header, B is a subregion of A.
// WebAssemblyException contains BBs in all its subregions (loops or
// exceptions), but MachineLoop may not, because MachineLoop does not
// contain BBs that don't have a path to its header even if they are
// dominated by its header. So here we should use
// WE->contains(ML->getHeader()), but not ML->contains(WE->getHeader()).
if ((ML && !WE) || (ML && WE && WE->contains(ML->getHeader()))) {
// If the smallest region containing MBB is a loop
if (LoopMap.count(ML))
return LoopMap[ML].get();
LoopMap[ML] = std::make_unique<ConcreteSortRegion<MachineLoop>>(ML);
return LoopMap[ML].get();
} else {
// If the smallest region containing MBB is an exception
if (ExceptionMap.count(WE))
return ExceptionMap[WE].get();
ExceptionMap[WE] =
std::make_unique<ConcreteSortRegion<WebAssemblyException>>(WE);
return ExceptionMap[WE].get();
}
}
MachineBasicBlock *SortRegionInfo::getBottom(const SortRegion *R) {
if (R->isLoop())
return getBottom(MLI.getLoopFor(R->getHeader()));
else
return getBottom(WEI.getExceptionFor(R->getHeader()));
}
MachineBasicBlock *SortRegionInfo::getBottom(const MachineLoop *ML) {
MachineBasicBlock *Bottom = ML->getHeader();
for (MachineBasicBlock *MBB : ML->blocks()) {
if (MBB->getNumber() > Bottom->getNumber())
Bottom = MBB;
// MachineLoop does not contain all BBs dominated by its header. BBs that
// don't have a path back to the loop header aren't included. But for the
// purpose of CFG sorting and stackification, we need a bottom BB among all
// BBs that are dominated by the loop header. So we check if there is any
// WebAssemblyException contained in this loop, and computes the most bottom
// BB of them all.
if (MBB->isEHPad()) {
MachineBasicBlock *ExBottom = getBottom(WEI.getExceptionFor(MBB));
if (ExBottom->getNumber() > Bottom->getNumber())
Bottom = ExBottom;
}
}
return Bottom;
}
MachineBasicBlock *SortRegionInfo::getBottom(const WebAssemblyException *WE) {
MachineBasicBlock *Bottom = WE->getHeader();
for (MachineBasicBlock *MBB : WE->blocks())
if (MBB->getNumber() > Bottom->getNumber())
Bottom = MBB;
return Bottom;
}
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