[llvm-dev] Removing LLVM_ALWAYS_INLINE from ADT classes

[Davide Italiano via llvm-dev]

On Thu, Jan 10, 2019 at 1:20 PM Davide Italiano <davide at freebsd.org> wrote:
>
> On Wed, Jan 9, 2019 at 2:18 PM Davide Italiano <davide at freebsd.org> wrote:
> >
> > On Wed, Jan 9, 2019 at 9:38 AM Mehdi AMINI <joker.eph at gmail.com> wrote:
> > >
> > >
> > >
> > > On Fri, Jan 4, 2019 at 3:15 PM Davide Italiano via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> > >>
> > >> Hi,
> > >> I would like to propose, based on a previous discussion on llvm-dev,
> > >> the following change.
> > >> https://reviews.llvm.org/D56337
> > >>
> > >> The main motivation for annotating member functions of ADT clases with
> > >> LLVM_ALWAYS_INLINE  was that of speeding up `check-llvm` at `-O0`.
> > >> Turns out this significantly degrades the debuggability of fundamental
> > >> classes in llvm itself, e.g. StringRef or SmallVector.
> > >
> > >
> > > It seems that the issue is not a problem with the inlining these functions but rather that they aren't emitted when inlined and so can't be called from the debugger.
> > >
> > > An alternative that preserves the inlining for the performance aspect *and* still emit them in debug build so that they are available in debug builds would be another macro that would expand to something like __attribute__((used)).
> > >
> >
>
> Your suggestion works just fine. I'll update the patch.
>
> * thread #1, queue = 'com.apple.main-thread', stop reason = step over
>     frame #0: 0x000000010000a110 lldb`main(argc=1,
> argv=0x00007ffeefbff9c8) at Driver.cpp:872
>    869
>    870  // Print stack trace on crash.
>    871  llvm::StringRef ToolName = llvm::sys::path::filename(argv[0]);
> -> 872  llvm::sys::PrintStackTraceOnErrorSignal(ToolName);
>    873  llvm::PrettyStackTraceProgram X(argc, argv);
>    874
>    875  // Parse arguments.
>
> (lldb) p ToolName.size()
> (size_t) $2 = 4
> (lldb) p ToolName.consume_front(llvm::StringRef("l"))
> (bool) $4 = true
> (lldb) p ToolName.consume_front(llvm::StringRef("a"))
> (bool) $5 = false
> (lldb) p ToolName.slice(1,2)
> (llvm::StringRef) $3 = (Data = "ldb", Length = 1)
>
> Thank you!

New review online: https://reviews.llvm.org/D56567

-- 
Davide

"There are no solved problems; there are only problems that are more
or less solved" -- Henri Poincare