[Lldb-commits] [PATCH] D43096: [lit] Update how clang and other binaries are found in per-configuration directories

Stella Stamenova via Phabricator via lldb-commits lldb-commits at lists.llvm.org
Thu Feb 8 20:24:56 PST 2018

stella.stamenova added inline comments.

Comment at: lit/CMakeLists.txt:10-13
zturner wrote:
> This only works if you're using a just-built clang, which might not be the case.  In fact, it's usually not the case, because it's common to want to run the test suite against a debug build of lldb but using a release build of clang (otherwise you'll be there all day waiting for it to finish).
> I feel like if the user specifies an absolute path to the test compiler on the command line, that should be what it uses -- always.  If we want to use a just built toolchain, maybe we need something else, like `-DLLDB_TEST_BUILT_CLANG=ON`, which would trigger this logic.
> As I don't use this configuration though, I'm interested in hearing your thoughts.
It actually does work in the case when a user specifies a compiler on the command line as well as when the just-built clang is used and the default today is to use the just-built clang.

As far as I can tell, you can specify the compiler with LLDB_TEST_C_COMPILER (or LLDB_TEST_CXX_COMPILER) when calling CMake or by passing a value to the tests directly with -C. I assume that you are concerned about the first case - when passing the property to CMake?

In that case LLDB_TEST_C_COMPILER is set to /path/to/compiler and these lines won't actually affect it - unless for some reason the path contained ${CMAKE_CFG_INTDIR}. If ${CMAKE_CFG_INTDIR} is a period, which is the likely scenario, it will just be replaced by another period since the build mode would be the same.

The only case when it might not work is if ${CMAKE_CFG_INTDIR} is in the path but not a period - but that is unlikely since the scenario would mean that ${CMAKE_CFG_INTDIR} is, say, $Configuration and the path that the user specified contains $Configuration AND it is different than the one they're using for LLDB.

On the other hand, without this change it is not possible to use the just-built compiler when using Visual Studio, for example, because the path to the just built compiler is not being set correctly and this particular substitution needs to happen here.

The way to make sure that both scenarios work always is to guard against the substitution when the user explicitly specifies a path or to enforce the sibstitution when they're using the just-built clang so a property like LLDB_TEST_BUILD_CLANG would work. If you think that the error scenario is likely enough, then we should add the property.


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