[llvm-dev] How is target_triple/default_triple handled in tests?

[Mehdi Amini via llvm-dev]

> On Oct 6, 2016, at 1:40 PM, Teresa Johnson via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> As part of trying to fix PR30610 (ThinLTO with module inline asm), I wanted to add an assert that we have a Target and an MCAsmParser when we have non-null module inline asm in IRObjectFile::CollectAsmUndefinedRefs. Otherwise it silently fails to parse the module inline asm, which I initially found when trying to add an 'opt' based test for my fix (because 'opt' wasn't initializing asm parsers, something I am fixing).
> 
> However, I had a test case failure in test/LTO/X86/current-section.ll, which has module asm, but no target triple. However, it does have a "REQUIRES: default_triple". Mehdi, looks like you added this as part of D12660. 
> I found that this is set to true in test/lit.cfg, and when I print out the config.target_triple there it is x86_64-unknown-linux-gnu. But when I print out the target triple on the Module in CollectAsmUndefinedRefs it is null. How is the config.target_triple supposed to propagate into the test - I assume that is the intention of requiring a default_triple?

Tools are usually adding the default triple when there is none. This is not a “feature” I like though.
The “default” triple is defined at configuration time, either you supply the cmake option otherwise it default to your host.
It is likely that llvm-lto is not overriding the triple (I rather have it asserting that there is a triple by the way).

Adding a triple to any test that relies on inline module asm seem the right thing to do to me, otherwise the test would break if someone were to configure with a default triple for a different target.

— 
Mehdi