[llvm-dev] Obtaining the origin function for a local var after inlining (original) (raw)

Adrian Prantl via llvm-dev llvm-dev at lists.llvm.org
Mon Sep 17 16:56:13 PDT 2018

On Sep 17, 2018, at 6:59 AM, Alexander Potapenko via llvm-dev <llvm-dev at lists.llvm.org> wrote:

(I think I've asked a similar question off-list a couple of times, but never got an answer) Hi folks, For [K]MSAN we need to figure out which inlined function a local var originally belonged to in the source file.

If you are looking at a llvm.dbg.declar/value/addr intrinsic, then the DILocation attached to the intrinsic indirectly points there:

DIScope *Scope = DILocation(dbg_intrinsic.getDebugLoc()).getScope(); while (!isa(Scope)) Scope = Scope->getScope(); auto *origFunction = cast(Scope);

if you want to find the function that it was inlined into then you need to follow the inlinedAt link in the DILoation.

-- adrian

E.g. when a local buffer %buf is declared in @bar(), but @bar() is inlined into @foo(), then there's a local %buf.i in @foo(), but we need to determine that the local came from @bar(). In the case of nested inline functions we need the deepest one.

Is there any existing code for that? If not, which debug info constructs do we need to look up to get this information? https://llvm.org/docs/SourceLevelDebugging.html mentions @llvm.dbg.addr as the source of information about a local var, but the ToT Clang doesn't emit it. There're calls to @llvm.debug.declare in the IR, but it's said to be deprecated, so I'm not sure if it's ok to use it. Thanks in advance, -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg

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