[CMake] Enable LLVM_ENABLE_PER_TARGET_RUNTIME_DIR by default on Linux

This makes the default build closer to a -DLLVM_ENABLE_RUNTIMES=all build.
The layout is arguably superior because different libraries of target triples
are in different directories, similar to GCC/Debian multiarch.

When LLVM_DEFAULT_TARGET_TRIPLE is x86_64-unknown-linux-gnu,
`lib/clang/14.0.0/lib/libclang_rt.asan-x86_64.a`
is moved to
`lib/clang/14.0.0/lib/x86_64-unknown-linux-gnu/libclang_rt.asan.a`.

In addition, if the host compiler supports -m32 (multilib),
`lib/clang/14.0.0/lib/libclang_rt.asan-i386.a`
is moved to
`lib/clang/14.0.0/lib/i386-unknown-linux-gnu/libclang_rt.asan.a`.

Clang has been detecting both paths for lib/Driver/ToolChains/Gnu.cpp since 2018 (D50547).

---

Note: Darwin needs to be disabled. The hierarchy needs to be sorted out.
The current -DLLVM_DEFAULT_TARGET_TRIPLE=off state is like:
```
lib/clang/14.0.0/lib/darwin/libclang_rt.profile_ios.a
lib/clang/14.0.0/lib/darwin/libclang_rt.profile_iossim.a
lib/clang/14.0.0/lib/darwin/libclang_rt.profile_osx.a
```

Windows needs to be disabled: https://reviews.llvm.org/D107799?id=368557#2963311

Differential Revision: https://reviews.llvm.org/D107799
This commit is contained in:
Fangrui Song 2021-09-15 09:32:59 -07:00
parent 210d72e9d6
commit f9dbca68d4

View File

@ -671,7 +671,12 @@ endif()
set(LLVM_TARGET_TRIPLE_ENV CACHE STRING "The name of environment variable to override default target. Disabled by blank.")
mark_as_advanced(LLVM_TARGET_TRIPLE_ENV)
set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR OFF CACHE BOOL
if(CMAKE_SYSTEM_NAME MATCHES "Linux")
set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_default ON)
else()
set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_default OFF)
endif()
set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR ${LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_default} CACHE BOOL
"Enable per-target runtimes directory")
set(LLVM_PROFDATA_FILE "" CACHE FILEPATH