[Lldb-commits] [PATCH] D116217: [lldb] Fix PR52702 by fixing Mangled::operator!

[PoYao Chang via Phabricator via lldb-commits]

rZhBoYao created this revision.
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Mangled::operator! claimes to be true if the object has an empty mangled and unmangled name, false otherwise, but it was actually true if the object has an empty mangled name. Luckily, this operator doesn't have a lot of users.

The broken logical not operator causes PR52702 <https://llvm.org/PR52702> as https://reviews.llvm.org/D106837 used Mangled::operator! in Symbol::SynthesizeNameIfNeeded. For example, consider the symbol "puts" in a hello world C program:

  // Inside Symbol::SynthesizeNameIfNeeded
  (lldb) p m_mangled
  (lldb_private::Mangled) $0 = (m_mangled = None, m_demangled = "puts")
  (lldb) p !m_mangled
  (bool) $1 = true          # should be false!!

This leads to Symbol::SynthesizeNameIfNeeded overwriting m_demangled part of Mangled (in this case "puts").

In conclusion, this patch turns
`callq  0x401030                  ; symbol stub for: ___lldb_unnamed_symbol36`
back into
 `callq  0x401030                  ; symbol stub for: puts` .


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D116217

Files:
  lldb/source/Core/Mangled.cpp


Index: lldb/source/Core/Mangled.cpp
===================================================================
--- lldb/source/Core/Mangled.cpp
+++ lldb/source/Core/Mangled.cpp
@@ -86,7 +86,7 @@
 //  Mangled mangled(...);
 //  if (!file_spec)
 //  { ...
-bool Mangled::operator!() const { return !m_mangled; }
+bool Mangled::operator!() const { return !m_mangled && !m_demangled; }
 
 // Clear the mangled and demangled values.
 void Mangled::Clear() {


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