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

[Zachary Turner via lldb-commits]

The problem is that CMAKE_CFG_INTDIR evaluates to something very common,
like “Debug” or “Release”, and replacing a common string like that in a
path creates more problems than it solves in my opinion. What if your build
dir is C:\src\LLDBDebugger\out\Debug\clang.exe? Debug appears twice in this
string so a replace might have unexpected results.

More importantly though, what if you *dont* want to use the just built
compiler? Maybe you specifically want to use the one from the release dir
because it’s faster, but your lldb is in the debug dir?

What if we say that if LLDB_TEST_JUST_BUILT_CLANG is ON, it initializes
these values as you’re doing now, but if you specify them manually it uses
exactly what you specify with no replacement? Would that work? (Having one
variable also saves some typing on the command line anyway)
On Thu, Feb 8, 2018 at 8:24 PM Stella Stamenova via Phabricator <
reviews at reviews.llvm.org> wrote:

> stella.stamenova added inline comments.
>
>
> ================
> Comment at: lit/CMakeLists.txt:10-13
> +string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE}
> LLDB_TEST_C_COMPILER ${LLDB_TEST_C_COMPILER})
> +string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE}
> LLDB_TEST_CXX_COMPILER ${LLDB_TEST_CXX_COMPILER})
> +string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} LLDB_LIBS_DIR
> ${LLVM_LIBRARY_OUTPUT_INTDIR})
> +string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} LLDB_TOOLS_DIR
> ${LLVM_RUNTIME_OUTPUT_INTDIR})
> ----------------
> 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.
>
>
>
> https://reviews.llvm.org/D43096
>
>
>
>
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