[NFC][DWARF] Use proper analog GNU attribute for the pc address

[djtodoro]

Summary

The low_pc is analog to the DW_AT_call_return_pc, since it describes the return address after the call. The DW_AT_call_pc is the address of the call instruction, and we don't use it at the moment.

[vsk]

LGTM. As a heads up, according to the coverage report the DW_AT_call_target case doesn’t seem covered by a test either (lab.llvm.org:8080/coverage/coverage-reports/coverage/Users/buildslave/jenkins/workspace/coverage/llvm-project/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp.html).

[djtodoro]

Thanks for the info! I will work on adding more test cases.

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

if (!useGNUAnalogForDwarf5Feature(DD))
     return Attr;
   switch (Attr) {
   case dwarf::DW_AT_call_all_calls:
     return dwarf::DW_AT_GNU_all_call_sites;
   case dwarf::DW_AT_call_target:
     return dwarf::DW_AT_GNU_call_site_target;
   case dwarf::DW_AT_call_origin:
     return dwarf::DW_AT_abstract_origin;
-  case dwarf::DW_AT_call_pc:
   case dwarf::DW_AT_call_return_pc:
     return dwarf::DW_AT_low_pc;
   case dwarf::DW_AT_call_value:
     return dwarf::DW_AT_GNU_call_site_value;
   case dwarf::DW_AT_call_tail_call:
     return dwarf::DW_AT_GNU_tail_call;
   default:
     llvm_unreachable("DWARF5 attribute with no GNU analog");