[clang] dd0356d - [CMake][PGO] Add option for using an external project to generate profile data (#78879)
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Fri Feb 2 11:35:12 PST 2024
Author: Tom Stellard
Date: 2024-02-02T11:35:08-08:00
New Revision: dd0356d741aefa25ece973d6cc4b55dcb73b84b4
URL: https://github.com/llvm/llvm-project/commit/dd0356d741aefa25ece973d6cc4b55dcb73b84b4
DIFF: https://github.com/llvm/llvm-project/commit/dd0356d741aefa25ece973d6cc4b55dcb73b84b4.diff
LOG: [CMake][PGO] Add option for using an external project to generate profile data (#78879)
The new CLANG_PGO_TRAINING_DATA_SOURCE_DIR allows users to specify a
CMake project to use for generating the profile data. For example, to
use the llvm-test-suite to generate profile data you would do:
$ cmake -G Ninja -B build -S llvm -C <path to
source>/clang/cmake/caches/PGO.cmake \
-DBOOTSTRAP_CLANG_PGO_TRAINING_DATA_SOURCE_DIR=<path to llvm-test-suite>
\
-DBOOTSTRAP_CLANG_PGO_TRAINING_DEPS=runtimes
Note that the CLANG_PERF_TRAINING_DEPS has been renamed to
CLANG_PGO_TRAINING_DEPS.
---------
Co-authored-by: Petr Hosek <phosek at google.com>
Added:
Modified:
clang/utils/perf-training/CMakeLists.txt
clang/utils/perf-training/perf-helper.py
llvm/docs/AdvancedBuilds.rst
Removed:
################################################################################
diff --git a/clang/utils/perf-training/CMakeLists.txt b/clang/utils/perf-training/CMakeLists.txt
index 601f40902fa34..61df987da7139 100644
--- a/clang/utils/perf-training/CMakeLists.txt
+++ b/clang/utils/perf-training/CMakeLists.txt
@@ -1,6 +1,10 @@
+include(LLVMExternalProjectUtils)
+
set(CLANG_PGO_TRAINING_DATA "${CMAKE_CURRENT_SOURCE_DIR}" CACHE PATH
"The path to a lit testsuite containing samples for PGO and order file generation"
)
+set(CLANG_PGO_TRAINING_DATA_SOURCE_DIR OFF CACHE STRING "Path to source directory containing cmake project with source files to use for generating pgo data")
+set(CLANG_PGO_TRAINING_DEPS "" CACHE STRING "Extra dependencies needed to build the PGO training data.")
if(LLVM_BUILD_INSTRUMENTED)
configure_lit_site_cfg(
@@ -11,11 +15,11 @@ if(LLVM_BUILD_INSTRUMENTED)
add_lit_testsuite(generate-profraw "Generating clang PGO data"
${CMAKE_CURRENT_BINARY_DIR}/pgo-data/
EXCLUDE_FROM_CHECK_ALL
- DEPENDS clang clear-profraw ${CLANG_PERF_TRAINING_DEPS}
+ DEPENDS clang clear-profraw ${CLANG_PGO_TRAINING_DEPS}
)
add_custom_target(clear-profraw
- COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py clean ${CMAKE_CURRENT_BINARY_DIR} profraw
+ COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py clean ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_BINARY_DIR}/profiles/ profraw
COMMENT "Clearing old profraw data")
if(NOT LLVM_PROFDATA)
@@ -26,9 +30,14 @@ if(LLVM_BUILD_INSTRUMENTED)
message(STATUS "To enable merging PGO data LLVM_PROFDATA has to point to llvm-profdata")
else()
add_custom_target(generate-profdata
- COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py merge ${LLVM_PROFDATA} ${CMAKE_CURRENT_BINARY_DIR}/clang.profdata ${CMAKE_CURRENT_BINARY_DIR}
+ COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py merge ${LLVM_PROFDATA} ${CMAKE_CURRENT_BINARY_DIR}/clang.profdata ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_BINARY_DIR}/profiles/
COMMENT "Merging profdata"
DEPENDS generate-profraw)
+ if (CLANG_PGO_TRAINING_DATA_SOURCE_DIR)
+ llvm_ExternalProject_Add(generate-profraw-external ${CLANG_PGO_TRAINING_DATA_SOURCE_DIR}
+ USE_TOOLCHAIN EXLUDE_FROM_ALL NO_INSTALL DEPENDS generate-profraw)
+ add_dependencies(generate-profdata generate-profraw-external)
+ endif()
endif()
endif()
diff --git a/clang/utils/perf-training/perf-helper.py b/clang/utils/perf-training/perf-helper.py
index 959bdba5c98cc..3ed42a187fd80 100644
--- a/clang/utils/perf-training/perf-helper.py
+++ b/clang/utils/perf-training/perf-helper.py
@@ -30,26 +30,28 @@ def findFilesWithExtension(path, extension):
def clean(args):
- if len(args) != 2:
+ if len(args) < 2:
print(
- "Usage: %s clean <path> <extension>\n" % __file__
+ "Usage: %s clean <paths> <extension>\n" % __file__
+ "\tRemoves all files with extension from <path>."
)
return 1
- for filename in findFilesWithExtension(args[0], args[1]):
- os.remove(filename)
+ for path in args[1:-1]:
+ for filename in findFilesWithExtension(path, args[-1]):
+ os.remove(filename)
return 0
def merge(args):
- if len(args) != 3:
+ if len(args) < 3:
print(
- "Usage: %s merge <llvm-profdata> <output> <path>\n" % __file__
+ "Usage: %s merge <llvm-profdata> <output> <paths>\n" % __file__
+ "\tMerges all profraw files from path into output."
)
return 1
cmd = [args[0], "merge", "-o", args[1]]
- cmd.extend(findFilesWithExtension(args[2], "profraw"))
+ for path in args[2:]:
+ cmd.extend(findFilesWithExtension(path, "profraw"))
subprocess.check_call(cmd)
return 0
diff --git a/llvm/docs/AdvancedBuilds.rst b/llvm/docs/AdvancedBuilds.rst
index 960b19fa5317f..ee178dd3772c4 100644
--- a/llvm/docs/AdvancedBuilds.rst
+++ b/llvm/docs/AdvancedBuilds.rst
@@ -145,6 +145,29 @@ that also enables ThinTLO, use the following command:
-DPGO_INSTRUMENT_LTO=Thin \
<path to source>/llvm
+By default, clang will generate profile data by compiling a simple
+hello world program. You can also tell clang use an external
+project for generating profile data that may be a better fit for your
+use case. The project you specify must either be a lit test suite
+(use the CLANG_PGO_TRAINING_DATA option) or a CMake project (use the
+CLANG_PERF_TRAINING_DATA_SOURCE_DIR option).
+
+For example, If you wanted to use the
+`LLVM Test Suite <https://github.com/llvm/llvm-test-suite/>`_ to generate
+profile data you would use the following command:
+
+.. code-block:: console
+
+ $ cmake -G Ninja -C <path to source>/clang/cmake/caches/PGO.cmake \
+ -DBOOTSTRAP_CLANG_PGO_TRAINING_DATA_SOURCE_DIR=<path to llvm-test-suite> \
+ -DBOOTSTRAP_CLANG_PGO_TRAINING_DEPS=runtimes
+
+The BOOTSTRAP\_ prefixes tells CMake to pass the variables on to the instrumented
+stage two build. And the CLANG_PGO_TRAINING_DEPS option let's you specify
+additional build targets to build before building the external project. The
+LLVM Test Suite requires compiler-rt to build, so we need to add the
+`runtimes` target as a dependency.
+
After configuration, building the stage2-instrumented-generate-profdata target
will automatically build the stage1 compiler, build the instrumented compiler
with the stage1 compiler, and then run the instrumented compiler against the
@@ -172,12 +195,12 @@ You can feed that file into the LLVM_PROFDATA_FILE option when you build your
optimized compiler.
It may be necessary to build additional targets before running perf training, such as
-builtins and runtime libraries. You can use the :code:`CLANG_PERF_TRAINING_DEPS` CMake
+builtins and runtime libraries. You can use the :code:`CLANG_PGO_TRAINING_DEPS` CMake
variable for that purpose:
.. code-block:: cmake
- set(CLANG_PERF_TRAINING_DEPS builtins runtimes CACHE STRING "")
+ set(CLANG_PGO_TRAINING_DEPS builtins runtimes CACHE STRING "")
The PGO cache has a slightly
diff erent stage naming scheme than other
multi-stage builds. It generates three stages: stage1, stage2-instrumented, and
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