Update build configuration to reduce friction

On systems with glibc < 2.34, the `-lpthread` option needs to be
included when linking with Google's benchmark and test frameworks.
However, the `pkg-config` command for `benchmark` needs to be explicitly
given the `--static` flag for this to be included. The static inclusion
has also been added to the Meson configuration.

I've also included some rudimentary logic to allow the Makefile to
shrink the scope of its compilation targets when an older compiler is
being used. I changed the benchmarks to run using `benchmark_main` in
the same way that the tests use `gtest_main`. Finally, I turned off
compilation of the package-internal tests for Google Benchmarks when
running in GitHub actions.

Author: mosullivan93

.github/workflows/c-cpp.yml

@@ -24,7 +24,7 @@ jobs:
         git clone https://github.com/google/benchmark.git
         cd benchmark
         cmake -E make_directory "build"
-        cmake -E chdir "build" cmake -DBENCHMARK_DOWNLOAD_DEPENDENCIES=on -DCMAKE_BUILD_TYPE=Release ../
+        cmake -E chdir "build" cmake -DBENCHMARK_ENABLE_GTEST_TESTS=OFF -DBENCHMARK_ENABLE_TESTING=OFF -DCMAKE_BUILD_TYPE=Release ../
         sudo cmake --build "build" --config Release --target install
 
     - name: Install Intel SDE
@@ -86,7 +86,7 @@ jobs:
         cd benchmark
         pip3 install -r requirements.txt
         cmake -E make_directory "build"
-        cmake -E chdir "build" cmake -DBENCHMARK_DOWNLOAD_DEPENDENCIES=on -DCMAKE_BUILD_TYPE=Release ../
+        cmake -E chdir "build" cmake -DBENCHMARK_ENABLE_GTEST_TESTS=OFF -DBENCHMARK_ENABLE_TESTING=OFF -DCMAKE_BUILD_TYPE=Release ../
         sudo cmake --build "build" --config Release --target install
 
     - name: Run bench-compare

.gitignore

@@ -33,5 +33,6 @@
 *.out
 *.app
 
+# Build or IDE artifacts
 **/.vscode
-
+/builddir/

Makefile

@@ -1,4 +1,11 @@
 CXX		?= g++-12
+CXXFLAGS	+= -I$(SRCDIR) -I$(UTILS) -O3
+GTESTCFLAGS	= `pkg-config --cflags gtest_main`
+GTESTLDFLAGS	= `pkg-config --static --libs gtest_main`
+GBENCHCFLAGS	= `pkg-config --cflags benchmark`
+GBENCHLDFLAGS	= `pkg-config --static --libs benchmark`
+MARCHFLAG	= -march=sapphirerapids
+
 SRCDIR		= ./src
 TESTDIR		= ./tests
 BENCHDIR	= ./benchmarks
@@ -8,13 +15,16 @@ TESTS		= $(wildcard $(TESTDIR)/*.cpp)
 BENCHS		= $(wildcard $(BENCHDIR)/*.cpp)
 TESTOBJS	= $(patsubst $(TESTDIR)/%.cpp,$(TESTDIR)/%.o,$(TESTS))
 BENCHOBJS	= $(patsubst $(BENCHDIR)/%.cpp,$(BENCHDIR)/%.o,$(BENCHS))
-BENCHOBJS	:= $(filter-out $(BENCHDIR)/main.o ,$(BENCHOBJS))
-CXXFLAGS	+= -I$(SRCDIR) -I$(UTILS)
-GTESTCFLAGS	= `pkg-config --cflags gtest_main`
-GTESTLDFLAGS	= `pkg-config --libs gtest_main`
-GBENCHCFLAGS	= `pkg-config --cflags benchmark`
-GBENCHLDFLAGS	= `pkg-config --libs benchmark`
-MARCHFLAG	= -march=sapphirerapids -O3
+
+# Compiling AVX512-FP16 instructions isn't possible for g++ < 12
+ifeq ($(shell expr `$(CXX) -dumpversion | cut -d '.' -f 1` \< 12), 1)
+	MARCHFLAG = -march=icelake-client
+	BENCHOBJS_SKIP += bench-qsortfp16.o
+	TESTOBJS_SKIP += test-qsortfp16.o
+endif
+
+BENCHOBJS	:= $(filter-out $(addprefix $(BENCHDIR)/, $(BENCHOBJS_SKIP)) ,$(BENCHOBJS))
+TESTOBJS	:= $(filter-out $(addprefix $(TESTDIR)/, $(TESTOBJS_SKIP)) ,$(TESTOBJS))
 
 all : test bench
 
@@ -31,7 +41,7 @@ $(BENCHDIR)/%.o : $(BENCHDIR)/%.cpp $(SRCS)
 	$(CXX) $(CXXFLAGS) $(MARCHFLAG) $(GBENCHCFLAGS) -c $< -o $@
 
 bench: $(BENCHOBJS) $(UTILS)/cpuinfo.o
-	$(CXX) $(BENCHDIR)/main.cpp $(BENCHOBJS) $(MARCHFLAG) $(CXXFLAGS) $(GBENCHLDFLAGS) $(UTILS)/cpuinfo.o -o benchexe
+	$(CXX) $(BENCHOBJS) $(UTILS)/cpuinfo.o $(MARCHFLAG) $(CXXFLAGS) -lbenchmark_main $(GBENCHLDFLAGS) -o benchexe
 
 meson:
 	meson setup --warnlevel 0 --buildtype plain builddir

benchmarks/main.cpp

@@ -6,8 +6,8 @@ src = include_directories('src')
 bench = include_directories('benchmarks')
 utils = include_directories('utils')
 tests = include_directories('tests')
-gtest_dep = dependency('gtest_main', required : true)
-gbench_dep = dependency('benchmark', required : true)
+gtest_dep = dependency('gtest_main', required : true, static: true)
+gbench_dep = dependency('benchmark', required : true, static: true)
 
 fp16code = '''#include<immintrin.h>
 int main() { 
@@ -28,9 +28,10 @@ testexe = executable('testexe',
                      link_whole : [libtests, libcpuinfo]
                     )
 
-benchexe = executable('benchexe', 'benchmarks/main.cpp',
+benchexe = executable('benchexe',
                       include_directories : [src, utils, bench],
                       dependencies : [gbench_dep],
+                      link_args: ['-lbenchmark_main'],
                       link_whole : [libbench, libcpuinfo],
                      )