[Lldb-commits] [PATCH] D113930: [LLDB][NativePDB] Fix function decl creation for class methods

[Zequan Wu via Phabricator via lldb-commits]

zequanwu added a comment.

In D113930#3173181 <https://reviews.llvm.org/D113930#3173181>, @labath wrote:

> While I'm not very familiar with PDBs or the process of clang ast creation, it sounds to me like there is something wrong here, and I want to make sure we're not using the deduplication to cover up some other issue. Were you able to understand (and ideally, explain) why we have the two parsing methods and why they end up trying to add the same method twice?

In `ModuleParseAllDebugSymbols`, these two functions (`NativePDB::ParseFunctions` and `NativePDB::ParseTypes`) are called with NativePDB plugin. `NativePDB::ParseFunctions` parses pdb debug stream <https://llvm.org/docs/PDB/DbiStream.html>, which contains information for those methods existing in the binary. Functions defined in the source files but removed by optimizations will not show up in it. This is where those methods get created at first time. `NativePDB::ParseTypes` parses pdb type stream <https://llvm.org/docs/PDB/TpiStream.html>, which contains type information for methods even if they are removed by optimizations. All class members are in the class's FieldList type record. `ParseTypes` visits all classes' FieldList to complete their TagRecord. This is where those methods get created the second time. We can refer to a function's type record (from type stream) using its symbol record (from debug stream) but not the opposite, since it's common multiple functions have the same signature, which will be just one type record for them. If we can change the order of function calls so that `ParseFunctions` is after `ParseTypes`, we check if a method is already created or not, not sure if it's okay.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113930/new/

https://reviews.llvm.org/D113930