Lines Matching +full:- +full:dcmake_cxx_compiler

2 How To Build Clang and LLVM with Profile-Guided Optimizations
8 PGO (Profile-Guided Optimization) allows your compiler to better optimize code
15 If you want to build other software with PGO, see the `end-user documentation
16 for PGO <https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization>`_.
22 See https://llvm.org/docs/AdvancedBuilds.html#multi-stage-pgo
29 compiler-rt. Despite the name, it performs four clean builds of Clang, so it
30 can take a while to run to completion. Please see the script's ``--help`` for
32 If you want to get the most out of PGO for a particular use-case (e.g. compiling
39 This script also supports a ``--dry-run`` option, which causes it to print
52 - runs all of Clang and LLVM's lit tests, and
53 - uses the instrumented Clang to build Clang, LLVM, and all of the other
58 - solid coverage of building C++,
59 - good coverage of building C,
60 - great coverage of running optimizations,
61 - great coverage of the backend for your host's architecture, and
62 - some coverage of other architectures (if other arches are supported backends).
76 First, you should have at least LLVM, Clang, and compiler-rt checked out
85   - Running the instrumented Clang/LLVM/lld/etc. on tasks that represent how
87   - Using a tool to convert the "raw" profiles generated above into a single,
98    to build the ``all`` target (e.g. ``ninja all`` or ``make -j4 all``).
102    - ``-DLLVM_BUILD_INSTRUMENTED=IR`` -- This causes us to build everything
104    - ``-DLLVM_BUILD_RUNTIME=No`` -- A few projects have bad interactions when
107    - ``-DCMAKE_C_COMPILER=/path/to/stage1/clang`` - Use the Clang we built in
109    - ``-DCMAKE_CXX_COMPILER=/path/to/stage1/clang++`` - Same as above.
118       benchmark recommended is to run ``check-clang`` and ``check-llvm`` in your
123       - ``-DCMAKE_C_COMPILER=/path/to/stage2/clang`` - Use the Clang we built in
125       - ``-DCMAKE_CXX_COMPILER=/path/to/stage2/clang++`` - Same as above.
128       ``-DCMAKE_BUILD_TYPE=RelWithDebInfo`` instead of
129       ``-DCMAKE_BUILD_TYPE=Release``. This will grant better coverage of
138      ``llvm-profdata`` (even if you only have one! The profile merge transforms
140      ``/path/to/stage1/llvm-profdata merge
141      -output=/path/to/output/profdata.prof path/to/stage2/profiles/*.profraw``.
143 4. Now, build your final, PGO-optimized Clang. To do this, you'll want to pass
146    - ``-DLLVM_PROFDATA_FILE=/path/to/output/profdata.prof`` - Use the PGO
148    - ``-DCMAKE_C_COMPILER=/path/to/stage1/clang`` - Use the Clang we built in
150    - ``-DCMAKE_CXX_COMPILER=/path/to/stage1/clang++`` - Same as above.
157      ``-DCMAKE_C_FLAGS='-Wno-backend-plugin'
158      -DCMAKE_CXX_FLAGS='-Wno-backend-plugin'`` to your CMake invocation.
161 Congrats! You now have a Clang built with profile-guided optimizations, and you
169 ``-DCLANG_TABLEGEN=/path/to/stage1/bin/clang-tblgen
170 -DLLVM_TABLEGEN=/path/to/stage1/bin/llvm-tblgen`` to steps 2 and onward to avoid