[Interest] Qt 5 LTO build on OS X 10.9 (and earlier)

[René J. V. Bertin]

Thiago Macieira wrote:

> On Friday 11 September 2015 10:24:32 René J.V. Bertin wrote:

> I've only ever tested LTO builds on Linux. That's where llvm-ar comes from --
> the *official* clang + LLVM build.

Quick check: my llvm 3.5.1 build on Linux indeed has llvm-ar, but it's got a 
-3.5 suffix like all other user-visible commands. I think that's what's official 
on Debian/Ubuntu at least; does Qt's build system pick up binaries named that 
way?

>> It seems that the ar command works too though it complains about and ignores
>> invalid debug info (which fits in with though doesn't fully explain my
>> experience that LTO builds lack debug information in shared libraries).
> 
> That depends on whether the .o files were fat or thin.

I don't know of a way to chose between those options with clang, but if I 
understand you correctly and the .o files were thin, wouldn't that also cause 
executables to lack debugging info? Because executables do seem to have 
everything for normal debugging.

R.