Commits on Aug 30, 2024

1. [clang] Don't add DWARF debug info when assembling .s with clang-cl /Z7 …

   This fixes a regression from f58330c.
   
   That commit changed the clang-cl options /Zi and /Z7 to be
   implemented as aliases of -g rather than having separate handling.
   
   This had the unintended effect, that when assembling .s files
   with clang-cl, the /Z7 option (which implies using CodeView debug
   info) was treated as a -g option, which causes `ClangAs::ConstructJob`
   to pick up the option as part of `Args.getLastArg(options::OPT_g_Group)`,
   which sets the `WantDebug` variable.
   
   Within `Clang::ConstructJob`, we check for whether explicit
   `-gdwarf` or `-gcodeview` options have been set, and if not, we
   pick the default debug format for the current toolchain. However,
   in `ClangAs`, if debug info has been enabled, it always adds DWARF
   debug info.
   
   Add similar logic in `ClangAs` - check if the user has explicitly
   requested either DWARF or CodeView, otherwise look up the toolchain
   default. If we (either implicitly or explicitly) should be producing
   CodeView, don't enable the default `ClangAs` DWARF generation.
   
   This fixes the issue, where assembling a single `.s` file with
   clang-cl, with the /Z7 option, causes the file to contain some DWARF
   sections. This causes the output executable to contain DWARF, in
   addition to the separate intended main PDB file.
   
   By having the output executable contain DWARF sections, LLDB only
   looks at the (very little) DWARF info in the executable, rather than
   looking for a separate standalone PDB file. This caused an issue
   with LLDB's tests, llvm#101710.

   

   mstorsjo committed Aug 30, 2024
   Configuration menu

   • View commit details
   • Copy full SHA for ac59e23
   • Browse repository at this point

   Copy the full SHA

   ac59e23 View commit details

   Browse the repository at this point in the history