[all-commits] [llvm/llvm-project] 8395f9: [lldb/DWARF] Remove parsing recursion when searchi...

[Pavel Labath via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8395f9cecd34af8a79c96e661e46a80d0d471fb1
      https://github.com/llvm/llvm-project/commit/8395f9cecd34af8a79c96e661e46a80d0d471fb1
  Author: Pavel Labath <pavel at labath.sk>
  Date:   2024-06-25 (Tue, 25 Jun 2024)

  Changed paths:
    M lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h

  Log Message:
  -----------
  [lldb/DWARF] Remove parsing recursion when searching for definition DIEs (#96484)

If ParseStructureLikeDIE (or ParseEnum) encountered a declaration DIE,
it would call FindDefinitionTypeForDIE. This returned a fully formed
type, which it achieved by recursing back into ParseStructureLikeDIE
with the definition DIE.

This obscured the control flow and caused us to repeat some work (e.g.
the UniqueDWARFASTTypeMap lookup), but it mostly worked until we tried
to delay the definition search in #90663. After this patch, the two
ParseStructureLikeDIE calls were no longer recursive, but rather the
second call happened as a part of the CompleteType() call. This opened
the door to inconsistencies, as the second ParseStructureLikeDIE call
was not aware it was called to process a definition die for an existing
type.

To make that possible, this patch removes the recusive type resolution
from this function, and leaves just the "find definition die"
functionality. After finding the definition DIE, we just go back to the
original ParseStructureLikeDIE call, and have it finish the parsing
process with the new DIE.

While this patch is motivated by the work on delaying the definition
searching, I believe it is also useful on its own.



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