[all-commits] [llvm/llvm-project] f66b69: [lldb] Fix lookup for global constants in namespaces

[Tonko Sabolčec via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f66b69a3925c547b1ee8ea93800f4bf7e31f407b
      https://github.com/llvm/llvm-project/commit/f66b69a3925c547b1ee8ea93800f4bf7e31f407b
  Author: Tonko Sabolčec <tonkosi123 at gmail.com>
  Date:   2021-11-23 (Tue, 23 Nov 2021)

  Changed paths:
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
    M lldb/test/API/lang/cpp/global_variables/TestCPPGlobalVariables.py
    M lldb/test/API/lang/cpp/global_variables/main.cpp

  Log Message:
  -----------
  [lldb] Fix lookup for global constants in namespaces

LLDB uses mangled name to construct a fully qualified name for global
variables. Sometimes DW_TAG_linkage_name attribute is missing from
debug info, so LLDB has to rely on parent entries to construct the
fully qualified name.

Currently, the fallback is handled when the parent DW_TAG is either
DW_TAG_compiled_unit or DW_TAG_partial_unit, which may not work well
for global constants in namespaces. For example:

  namespace ns {
    const int x = 10;
  }

may produce the following debug info:

  <1><2a>: Abbrev Number: 2 (DW_TAG_namespace)
     <2b>   DW_AT_name        : (indirect string, offset: 0x5e): ns
  <2><2f>: Abbrev Number: 3 (DW_TAG_variable)
     <30>   DW_AT_name        : (indirect string, offset: 0x61): x
     <34>   DW_AT_type        : <0x3c>
     <38>   DW_AT_decl_file   : 1
     <39>   DW_AT_decl_line   : 2
     <3a>   DW_AT_const_value : 10

Since the fallback didn't handle the case when parent tag is
DW_TAG_namespace, LLDB wasn't able to match the variable by its fully
qualified name "ns::x". This change fixes this by additional check
if the parent is a DW_TAG_namespace.

Reviewed By: werat, clayborg

Differential Revision: https://reviews.llvm.org/D112147