Add BENCHMARK_BUILD_32_BITS option and add builders to test it (#360)

* Add BENCHMARK_BUILD_32_BITS option and add builders to test it

* Attempt to fix travis configuration

* Make add_required_cxx_compiler_flag cause an error when the flag isn't supported

* add gcc-multilib dependancy on travis

* attempt to fix travis.yml parsing error

* Require g++-multilib instead of gcc-multilib

* Add 32 bit release configurations

* Attempt to fix libc++ travis build w/ 32 bits

* Work around CMake configuration failure on Travis

.travis-libcxx-setup.sh

@@ -10,12 +10,18 @@ git clone --depth=1 https://github.com/llvm-mirror/llvm.git llvm-source
 git clone --depth=1 https://github.com/llvm-mirror/libcxx.git llvm-source/projects/libcxx
 git clone --depth=1 https://github.com/llvm-mirror/libcxxabi.git llvm-source/projects/libcxxabi
 
+# Setup libc++ options
+if [ -z "$BUILD_32_BITS" ]; then
+  export BUILD_32_BITS=OFF && echo disabling 32 bit build
+fi
+
 # Build and install libc++ (Use unstable ABI for better sanitizer coverage)
 mkdir llvm-build && cd llvm-build
 cmake -DCMAKE_C_COMPILER=${C_COMPILER} -DCMAKE_CXX_COMPILER=${COMPILER} \
       -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_INSTALL_PREFIX=/usr \
       -DLIBCXX_ABI_UNSTABLE=ON \
       -DLLVM_USE_SANITIZER=${LIBCXX_SANITIZER} \
+      -DLLVM_BUILD_32_BITS=${BUILD_32_BITS} \
       ../llvm-source
 make cxx -j2
 sudo make install-cxxabi install-cxx

.travis.yml

@@ -20,6 +20,18 @@ matrix:
           env: COMPILER=g++ C_COMPILER=gcc       BUILD_TYPE=Debug
         - compiler: gcc
           env: COMPILER=g++ C_COMPILER=gcc       BUILD_TYPE=Release
+        - compiler: gcc
+          addons:
+            apt:
+              packages:
+                - g++-multilib
+          env: COMPILER=g++ C_COMPILER=gcc       BUILD_TYPE=Debug   BUILD_32_BITS=ON
+        - compiler: gcc
+          addons:
+            apt:
+              packages:
+                - g++-multilib
+          env: COMPILER=g++ C_COMPILER=gcc       BUILD_TYPE=Release BUILD_32_BITS=ON
         - compiler: gcc
           addons:
             apt:
@@ -44,6 +56,39 @@ matrix:
             - COMPILER=clang++-3.8 C_COMPILER=clang-3.8 BUILD_TYPE=Debug
             - LIBCXX_BUILD=1
             - EXTRA_FLAGS="-stdlib=libc++"
+        - compiler: clang
+          addons:
+            apt:
+              packages:
+                clang-3.8
+          env:
+            - COMPILER=clang++-3.8 C_COMPILER=clang-3.8 BUILD_TYPE=Release
+            - LIBCXX_BUILD=1
+            - EXTRA_FLAGS="-stdlib=libc++"
+        # Clang w/ 32bit libc++
+        - compiler: clang
+          addons:
+            apt:
+              packages:
+                - clang-3.8
+                - g++-multilib
+          env:
+            - COMPILER=clang++-3.8 C_COMPILER=clang-3.8 BUILD_TYPE=Debug
+            - LIBCXX_BUILD=1
+            - BUILD_32_BITS=ON
+            - EXTRA_FLAGS="-stdlib=libc++ -m32"
+        # Clang w/ 32bit libc++
+        - compiler: clang
+          addons:
+            apt:
+              packages:
+                - clang-3.8
+                - g++-multilib
+          env:
+            - COMPILER=clang++-3.8 C_COMPILER=clang-3.8 BUILD_TYPE=Release
+            - LIBCXX_BUILD=1
+            - BUILD_32_BITS=ON
+            - EXTRA_FLAGS="-stdlib=libc++ -m32"
         # Clang w/ libc++, ASAN, UBSAN
         - compiler: clang
           addons:
@@ -77,6 +122,9 @@ matrix:
             - EXTRA_FLAGS="-stdlib=libc++ -g -O2 -fno-omit-frame-pointer -fsanitize=thread -fno-sanitize-recover=all"
 
 before_script:
+    - if [ -z "$BUILD_32_BITS" ]; then
+        export BUILD_32_BITS=OFF && echo disabling 32 bit build;
+      fi
     - if [ -n "${LIBCXX_BUILD}" ]; then
         source .travis-libcxx-setup.sh;
       fi
@@ -90,7 +138,7 @@ install:
     fi
 
 script:
-    - cmake -DCMAKE_C_COMPILER=${C_COMPILER} -DCMAKE_CXX_COMPILER=${COMPILER} -DCMAKE_BUILD_TYPE=${BUILD_TYPE} -DCMAKE_CXX_FLAGS="${EXTRA_FLAGS}" ..
+    - cmake -DCMAKE_C_COMPILER=${C_COMPILER} -DCMAKE_CXX_COMPILER=${COMPILER} -DCMAKE_BUILD_TYPE=${BUILD_TYPE} -DCMAKE_CXX_FLAGS="${EXTRA_FLAGS}" -DBENCHMARK_BUILD_32_BITS=${BUILD_32_BITS} ..
     - make
     - make CTEST_OUTPUT_ON_FAILURE=1 test
 

CMakeLists.txt

@@ -14,6 +14,8 @@ option(BENCHMARK_ENABLE_TESTING "Enable testing of the benchmark library." ON)
 option(BENCHMARK_ENABLE_EXCEPTIONS "Enable the use of exceptions in the benchmark library." ON)
 option(BENCHMARK_ENABLE_LTO "Enable link time optimisation of the benchmark library." OFF)
 option(BENCHMARK_USE_LIBCXX "Build and test using libc++ as the standard library." OFF)
+option(BENCHMARK_BUILD_32_BITS "Build a 32 bit version of the library" OFF)
+
 # Make sure we can import out CMake functions
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 
@@ -34,6 +36,10 @@ include(CheckCXXCompilerFlag)
 include(AddCXXCompilerFlag)
 include(CXXFeatureCheck)
 
+if (BENCHMARK_BUILD_32_BITS)
+  add_required_cxx_compiler_flag(-m32)
+endif()
+
 if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
   # Turn compiler warnings up to 11
   string(REGEX REPLACE "[-/]W[1-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")

cmake/AddCXXCompilerFlag.cmake

@@ -19,14 +19,21 @@ set(__add_cxx_compiler_flag INCLUDED)
 
 include(CheckCXXCompilerFlag)
 
-function(add_cxx_compiler_flag FLAG)
+function(mangle_compiler_flag FLAG OUTPUT)
   string(TOUPPER "HAVE_CXX_FLAG_${FLAG}" SANITIZED_FLAG)
   string(REPLACE "+" "X" SANITIZED_FLAG ${SANITIZED_FLAG})
   string(REGEX REPLACE "[^A-Za-z_0-9]" "_" SANITIZED_FLAG ${SANITIZED_FLAG})
   string(REGEX REPLACE "_+" "_" SANITIZED_FLAG ${SANITIZED_FLAG})
-  set(CMAKE_REQUIRED_FLAGS "${FLAG}")
+  set(${OUTPUT} "${SANITIZED_FLAG}" PARENT_SCOPE)
-  check_cxx_compiler_flag("${FLAG}" ${SANITIZED_FLAG})
+endfunction(mangle_compiler_flag)
-  if(${SANITIZED_FLAG})
+
+function(add_cxx_compiler_flag FLAG)
+  mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
+  set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
+  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}")
+  check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
+  set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
+  if(${MANGLED_FLAG})
     set(VARIANT ${ARGV1})
     if(ARGV1)
       string(TOUPPER "_${VARIANT}" VARIANT)
@@ -35,3 +42,23 @@ function(add_cxx_compiler_flag FLAG)
   endif()
 endfunction()
 
+function(add_required_cxx_compiler_flag FLAG)
+  mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
+  set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
+  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}")
+  check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
+  set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
+  if(${MANGLED_FLAG})
+    set(VARIANT ${ARGV1})
+    if(ARGV1)
+      string(TOUPPER "_${VARIANT}" VARIANT)
+    endif()
+    set(CMAKE_CXX_FLAGS${VARIANT} "${CMAKE_CXX_FLAGS${VARIANT}} ${FLAG}" PARENT_SCOPE)
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
+    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
+    set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
+    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}" PARENT_SCOPE)
+  else()
+    message(FATAL_ERROR "Required flag '${FLAG}' is not supported by the compiler")
+  endif()
+endfunction()