[llvm-dev] llvm::UpgradeDebugInfo does a full verification

[Adrian Prantl via llvm-dev]

> On Jan 23, 2018, at 11:01 PM, Carlo Kok via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Hi,
> 
> I noticed that since recently UpgradeDebugInfo (Which is called for loading any bitcode from disk/memory) does a full bitcode verification. Is this on purpose or is this a mistake? Seems to have a fair amount of overhead.

That is be design, though there are bugs in the LTO pipeline where we run the Verifier more than once. "Upgrading" debug info means checking for a malformed metadata graph (for example, produced by older, buggy versions of LLVM, or buggy frontends) that would crash LLVM. The "upgrade" consists of stripping the debug info form the module.

-- adrian