[DwarfGenerator] Emit dwarf address section when dwarf version is not less than 4

[lkail]

Summary

Some targets (like AIX) might not feature dwarf address section due to low dwarf version. Check before emitting one.

Fixed DebugInfo unit test failures in https://lab.llvm.org/buildbot/#/builders/214/builds/5739.

[benmxwl-arm]

llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp

586–587

Maybe change this to if (Version >= 5), it looks like the DWARF5 tests are already disabled for AIX, so that should achieve the same effect (if that were not the case these tests would still fail on AIX with this change).

[lkail]

Check dwarf version number per @benmxwl-arm 's suggestion.

[benmxwl-arm]

If this fixes the test failures this LGTM

[qiucf]

Is this an AIX only restriction or for all DWARF <= 4?

[lkail]

In D143561#4117072, @qiucf wrote:

Is this an AIX only restriction or for all DWARF <= 4?

For all DWARF <= 4. See https://github.com/llvm/llvm-project/blob/32b3f13337ef0bf747705d058f4772c7fdabd736/llvm/include/llvm/MC/MCObjectFileInfo.h#L118.

[qiucf]

Looks good, thanks

llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp

StringRef dwarfgen::Generator::generate() {
   }
   Abbreviations.Emit(Asm.get(), TLOF->getDwarfAbbrevSection());
 
   StringPool->emitStringOffsetsTableHeader(*Asm, TLOF->getDwarfStrOffSection(),
                                            StringOffsetsStartSym);
   StringPool->emit(*Asm, TLOF->getDwarfStrSection(),
                    TLOF->getDwarfStrOffSection());
 
+  if (Asm->getDwarfVersion() >= 5)
     AddressPool.emit(*Asm, TLOF->getDwarfAddrSection(), AddrTableStartSym);
 
   MS->switchSection(TLOF->getDwarfInfoSection());
   for (auto &CU : CompileUnits) {
     uint16_t Version = CU->getVersion();
     auto Length = CU->getLength();
     MC->setDwarfVersion(Version);
     assert(Length != -1U);
     Asm->emitInt32(Length);
     Asm->emitInt16(Version);