forked from OSchip/llvm-project
1872096f1e
Now that MachineBasicBlock::reverse_instr_iterator knows when it's at
the end (since r281168 and r281170), implement
MachineBasicBlock::reverse_iterator directly on top of an
ilist::reverse_iterator by adding an IsReverse template parameter to
MachineInstrBundleIterator. This replaces another hard-to-reason-about
use of std::reverse_iterator on list iterators, matching the changes for
ilist::reverse_iterator from r280032 (see the "out of scope" section at
the end of that commit message). MachineBasicBlock::reverse_iterator
now has a handle to the current node and has obvious invalidation
semantics.
r280032 has a more detailed explanation of how list-style reverse
iterators (invalidated when the pointed-at node is deleted) are
different from vector-style reverse iterators like std::reverse_iterator
(invalidated on every operation). A great motivating example is this
commit's changes to lib/CodeGen/DeadMachineInstructionElim.cpp.
Note: If your out-of-tree backend deletes instructions while iterating
on a MachineBasicBlock::reverse_iterator or converts between
MachineBasicBlock::iterator and MachineBasicBlock::reverse_iterator,
you'll need to update your code in similar ways to r280032. The
following table might help:
[Old] ==> [New]
delete &*RI, RE = end() delete &*RI++
RI->erase(), RE = end() RI++->erase()
reverse_iterator(I) std::prev(I).getReverse()
reverse_iterator(I) ++I.getReverse()
--reverse_iterator(I) I.getReverse()
reverse_iterator(std::next(I)) I.getReverse()
RI.base() std::prev(RI).getReverse()
RI.base() ++RI.getReverse()
--RI.base() RI.getReverse()
std::next(RI).base() RI.getReverse()
(For more details, have a look at r280032.)
llvm-svn: 281172
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| .. | ||
| ARMException.cpp | ||
| AddressPool.cpp | ||
| AddressPool.h | ||
| AsmPrinter.cpp | ||
| AsmPrinterDwarf.cpp | ||
| AsmPrinterHandler.h | ||
| AsmPrinterInlineAsm.cpp | ||
| ByteStreamer.h | ||
| CMakeLists.txt | ||
| CodeViewDebug.cpp | ||
| CodeViewDebug.h | ||
| DIE.cpp | ||
| DIEHash.cpp | ||
| DIEHash.h | ||
| DbgValueHistoryCalculator.cpp | ||
| DbgValueHistoryCalculator.h | ||
| DebugHandlerBase.cpp | ||
| DebugHandlerBase.h | ||
| DebugLocEntry.h | ||
| DebugLocStream.cpp | ||
| DebugLocStream.h | ||
| DwarfAccelTable.cpp | ||
| DwarfAccelTable.h | ||
| DwarfCFIException.cpp | ||
| DwarfCompileUnit.cpp | ||
| DwarfCompileUnit.h | ||
| DwarfDebug.cpp | ||
| DwarfDebug.h | ||
| DwarfException.h | ||
| DwarfExpression.cpp | ||
| DwarfExpression.h | ||
| DwarfFile.cpp | ||
| DwarfFile.h | ||
| DwarfStringPool.cpp | ||
| DwarfStringPool.h | ||
| DwarfUnit.cpp | ||
| DwarfUnit.h | ||
| EHStreamer.cpp | ||
| EHStreamer.h | ||
| ErlangGCPrinter.cpp | ||
| LLVMBuild.txt | ||
| OcamlGCPrinter.cpp | ||
| WinException.cpp | ||
| WinException.h | ||