At the moment if LLVM_BUILD_INSTRUMENTED is set to True
one has to set LLVM_PROFTDATA even if it's not really used
(because of message(FATAL_ERROR ...)).
Building the instrumented version of Clang can be useful even if
one doesn't plan to build the target generate-profdata
(currently that target would only compile utils/perf-training/cxx/hello_world.cpp).
For example, one can run the instrumented version of Clang
via a separate build system against a different codebase,
collect/analyze the profiles and merge them by llvm-profdata later.
Differential revision: https://reviews.llvm.org/D38859
llvm-svn: 315665
This diff fixes the clean build of the target generate-order-file.
In llvm/tools/clang/CMakeLists.txt
add_subdirectory(utils/perf-training) should go after the block where
the value of the variable CLANG_ORDER_FILE is set - otherwise
(tested with cmake's version 3.6.2) the arguments of perf-helper.py gen-order-file
will be ill-formed (CLANG_ORDER_FILE will be empty).
Differential revision: https://reviews.llvm.org/D28153
llvm-svn: 290781
Dtrace is implemented to try and minimize performance impact on the process being traced. This results in dtrace dropping samples if it is taking too many CPU resources. Multi-threading dtrace increases the sample drop rate dramatically.
llvm-svn: 266213
This is re-landing r260742. I've reworked the conditionals so that it only hits when targeting Apple platforms with ld64.
Original Summary:
With this change generating clang order files using dtrace uses the following workflow:
cmake <whatever options you want>
ninja generate-order-file
ninja clang
This patch works by setting a default path to the order file (which can be overridden by the user). If the order file doesn't exist during configuration CMake will create an empty one.
CMake then ties up the dependencies between the clang link job and the order file, and generate-order-file overwrites CLANG_ORDER_FILE with the new order file.
llvm-svn: 265864
This appears to be passing '-Wl,-order_file' to Linux link commands,
which then causes the linker to silently, behind the scenes, write the
output to 'rder_file' instead of somewhere else. Will work with Chris to
figure out the proper support for this, but so far there are numerous
people who can't get Clang to update when they build because of this.
llvm-svn: 261054
Summary:
This commit re-lands r259862. The underlying cause of the build breakage was an incorrectly written capabilities test. In tools/Driver/CMakeLists.txt I was attempting to check if a linker flag worked, the test was passing it to the compiler, not the linker. CMake doesn't have a linker test, so we have a hand-rolled one.
Original Patch Review: http://reviews.llvm.org/D16896
Original Summary:
With this change generating clang order files using dtrace uses the following workflow:
cmake <whatever options you want>
ninja generate-order-file
ninja clang
This patch works by setting a default path to the order file (which can be overridden by the user). If the order file doesn't exist during configuration CMake will create an empty one.
CMake then ties up the dependencies between the clang link job and the order file, and generate-order-file overwrites CLANG_ORDER_FILE with the new order file.
Reviewers: bogner
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D16999
llvm-svn: 260742
This reverts commit r259862, and attempts to fix builder CMakeCaches.
Will try this again some other time...
Conflicts:
CMakeLists.txt
tools/driver/CMakeLists.txt
llvm-svn: 259872
Summary:
With this change generating clang order files using dtrace uses the following workflow:
cmake <whatever options you want>
ninja generate-order-file
ninja clang
This patch works by setting a default path to the order file (which can be overridden by the user). If the order file doesn't exist during configuration CMake will create an empty one.
CMake then ties up the dependencies between the clang link job and the order file, and generate-order-file overwrites CLANG_ORDER_FILE with the new order file.
Reviewers: bogner
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D16896
llvm-svn: 259862
Summary:
This patch extends the lit-based perf-training tooling supplied for PGO data generation to also generate linker order files using dtrace.
This patch should work on any system that has dtrace. If CMake can find the dtrace tool it will generate a target 'generate-order-file' which will run the per-training tests wrapped by dtrace to capture function entries. There are several algorithms implemented for sorting the order files which can be experimented with for best performance. The dtrace wrapper also supports bot oneshot and pid probes.
The perf-helper.py changes to support order file construction are ported from internal changes by ddunbar; he gets all the credit for the hard work here, I just copy and pasted.
Note: I've tested these patches on FreeBSD and OS X 10.10.
Reviewers: ddunbar, bogner, silvas
Subscribers: llvm-commits, emaste
Differential Revision: http://reviews.llvm.org/D16134
llvm-svn: 257934
Summary:
This patch adds support for using LIT to drive generating PGO profile data for clang.
This first pass implementation should work on Linux and Unix based platforms. If you build clang using CMake with LLVM_BUILD_INSTRUMENTED=On the CMake build generates a generate-profdata target that will use the just-built clang to build any test files (see hello_world.cpp as an example). Each test compile will generate profraw files for each clang process. After all tests have run CMake will merge the profraw files using llvm-profdata.
Future opportunities for extension:
* Support for Build->Profile->Build bootstrapping
* Support for linker order file generation using a similar mechanism and the same training data
* Support for Windows
Reviewers: dexonsmith, friss, bogner, cmatthews, vsk, silvas
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D15462
llvm-svn: 255740
Alexander Shaposhnikov