Use Link Time Optimisation whenever possible (#6967)

.github/workflows/osrm-backend.yml

@@ -200,6 +200,7 @@ jobs:
  CCOMPILER: clang-15
  CXXCOMPILER: clang++-15
  CUCUMBER_TIMEOUT: 60000
+ ENABLE_LTO: OFF
 
  - name: clang-15-debug
  continue-on-error: false
@@ -210,6 +211,7 @@ jobs:
  CCOMPILER: clang-15
  CXXCOMPILER: clang++-15
  CUCUMBER_TIMEOUT: 60000
+ ENABLE_LTO: OFF
 
  - name: clang-18-debug-clang-tidy
  continue-on-error: false
@@ -232,6 +234,7 @@ jobs:
  CCOMPILER: clang-14
  CXXCOMPILER: clang++-14
  CUCUMBER_TIMEOUT: 60000
+ ENABLE_LTO: OFF
 
  - name: clang-13-release
  continue-on-error: false
@@ -242,6 +245,7 @@ jobs:
  CCOMPILER: clang-13
  CXXCOMPILER: clang++-13
  CUCUMBER_TIMEOUT: 60000
+ ENABLE_LTO: OFF
 
  - name: conan-linux-debug-asan-ubsan
  continue-on-error: false
@@ -253,6 +257,7 @@ jobs:
  CXXCOMPILER: clang++-15
  ENABLE_CONAN: ON
  ENABLE_SANITIZER: ON
+ ENABLE_LTO: OFF
 
  - name: conan-linux-release
  continue-on-error: false
@@ -263,6 +268,7 @@ jobs:
  CCOMPILER: clang-15
  CXXCOMPILER: clang++-15
  ENABLE_CONAN: ON
+ ENABLE_LTO: OFF
 
  - name: gcc-14-release
  continue-on-error: false
@@ -361,6 +367,7 @@ jobs:
  TARGET_ARCH: ${{ matrix.TARGET_ARCH }}
  OSRM_CONNECTION_RETRIES: ${{ matrix.OSRM_CONNECTION_RETRIES }}
  OSRM_CONNECTION_EXP_BACKOFF_COEF: ${{ matrix.OSRM_CONNECTION_EXP_BACKOFF_COEF }}
+ ENABLE_LTO: ${{ matrix.ENABLE_LTO }}
  steps:
  - uses: actions/checkout@v4
  - name: Build machine architecture
@@ -521,6 +528,7 @@ jobs:
  -DENABLE_SANITIZER=${ENABLE_SANITIZER:-OFF} \
  -DBUILD_TOOLS=${BUILD_TOOLS:-OFF} \
  -DENABLE_CCACHE=ON \
+ -DENABLE_LTO=${ENABLE_LTO:-ON} \
  -DCMAKE_INSTALL_PREFIX=${OSRM_INSTALL_DIR}
  make --jobs=${JOBS}
 

CHANGELOG.md

@@ -24,6 +24,7 @@
  - NodeJS:
  - CHANGED: Use node-api instead of NAN. [#6452](https://github.com/Project-OSRM/osrm-backend/pull/6452)
  - Misc:
+ - CHANGED: Use Link Time Optimisation whenever possible. [#6967](https://github.com/Project-OSRM/osrm-backend/pull/6967)
  - CHANGED: Use struct instead of tuple to define UnpackedPath. [#6974](https://github.com/Project-OSRM/osrm-backend/pull/6974)
  - CHANGED: Micro performance optimisation in map matching. [#6976](https://github.com/Project-OSRM/osrm-backend/pull/6976)
  - CHANGED: Re-use priority queue in StaticRTree. [#6952](https://github.com/Project-OSRM/osrm-backend/pull/6952)

CMakeLists.txt

@@ -31,11 +31,12 @@ option(ENABLE_ASSERTIONS "Use assertions in release mode" OFF)
 option(ENABLE_DEBUG_LOGGING "Use debug logging in release mode" OFF)
 option(ENABLE_COVERAGE "Build with coverage instrumentalisation" OFF)
 option(ENABLE_SANITIZER "Use memory sanitizer for Debug build" OFF)
-option(ENABLE_LTO "Use LTO if available" OFF)
+option(ENABLE_LTO "Use Link Time Optimisation" ON)
 option(ENABLE_FUZZING "Fuzz testing using LLVM's libFuzzer" OFF)
 option(ENABLE_NODE_BINDINGS "Build NodeJs bindings" OFF)
 option(ENABLE_CLANG_TIDY "Enables clang-tidy checks" OFF)
 
+
 if (ENABLE_CLANG_TIDY)
  find_program(CLANG_TIDY_COMMAND NAMES clang-tidy)
  if(NOT CLANG_TIDY_COMMAND)
@@ -57,6 +58,18 @@ if (POLICY CMP0074)
 endif()
 project(OSRM C CXX)
 
+
+if(ENABLE_LTO AND (CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES MinRelSize OR CMAKE_BUILD_TYPE MATCHES RelWithDebInfo))
+ include(CheckIPOSupported)
+ check_ipo_supported(RESULT LTO_SUPPORTED OUTPUT error)
+ if(LTO_SUPPORTED)
+ message(STATUS "IPO / LTO enabled")
+ set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
+ else()
+ message(FATAL_ERROR "IPO / LTO not supported: <${error}>")
+ endif()
+endif()
+
 # add @loader_path/$ORIGIN to rpath to make binaries relocatable
 if (APPLE)
  set(CMAKE_BUILD_RPATH "@loader_path")
@@ -208,17 +221,6 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
  set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -Og -ggdb")
 endif()
 
-if(ENABLE_LTO AND (CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES MinRelSize OR CMAKE_BUILD_TYPE MATCHES RelWithDebInfo))
- include(CheckIPOSupported)
- check_ipo_supported(RESULT LTO_SUPPORTED OUTPUT error)
- if(LTO_SUPPORTED)
- message(STATUS "IPO / LTO enabled")
- set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
- else()
- message(WARNING "IPO / LTO not supported: <${error}>")
- endif()
-endif()
-
 set(MAYBE_COVERAGE_LIBRARIES "")
 if (ENABLE_COVERAGE)
  if (NOT CMAKE_BUILD_TYPE MATCHES "Debug")
@@ -290,6 +292,7 @@ include_directories(SYSTEM ${MICROTAR_INCLUDE_DIR})
 
 add_library(MICROTAR OBJECT "${CMAKE_CURRENT_SOURCE_DIR}/third_party/microtar/src/microtar.c")
 set_property(TARGET MICROTAR PROPERTY POSITION_INDEPENDENT_CODE ON)
+
 target_no_warning(MICROTAR unused-variable)
 target_no_warning(MICROTAR format)
 

cmake/warnings.cmake

@@ -64,7 +64,6 @@ add_warning(init-self)
 add_warning(bool-compare)
 add_warning(logical-not-parentheses)
 add_warning(logical-op)
-add_warning(maybe-uninitialized)
 add_warning(misleading-indentation)
 # `no-` prefix is part of warning name(i.e. doesn't mean we are disabling it)
 add_warning(no-return-local-addr)
@@ -84,3 +83,6 @@ no_warning(comma-subscript)
 no_warning(ambiguous-reversed-operator)
 no_warning(restrict)
 no_warning(free-nonheap-object)
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+ no_warning(stringop-overflow)
+endif()

docker/Dockerfile-alpine

@@ -31,7 +31,7 @@ RUN NPROC=${BUILD_CONCURRENCY:-$(nproc)} && \
  case ${DOCKER_TAG} in *"-debug"*) BUILD_TYPE="Debug";; esac && \
  case ${DOCKER_TAG} in *"-assertions"*) BUILD_TYPE="RelWithDebInfo" && ENABLE_ASSERTIONS="On" && BUILD_TOOLS="On";; esac && \
  echo "Building ${BUILD_TYPE} with ENABLE_ASSERTIONS=${ENABLE_ASSERTIONS} BUILD_TOOLS=${BUILD_TOOLS}" && \
- cmake .. -DCMAKE_BUILD_TYPE=${BUILD_TYPE} -DENABLE_ASSERTIONS=${ENABLE_ASSERTIONS} -DBUILD_TOOLS=${BUILD_TOOLS} -DENABLE_LTO=On && \
+ cmake .. -DCMAKE_BUILD_TYPE=${BUILD_TYPE} -DENABLE_ASSERTIONS=${ENABLE_ASSERTIONS} -DBUILD_TOOLS=${BUILD_TOOLS} -DENABLE_LTO=OFF && \
  make -j${NPROC} install && \
  cd ../profiles && \
  cp -r * /opt && \

docker/Dockerfile-debian

@@ -21,7 +21,7 @@ COPY . /src
 WORKDIR /src
 
 RUN NPROC=${BUILD_CONCURRENCY:-$(nproc)} && \
- export CXXFLAGS="-Wno-array-bounds -Wno-uninitialized" && \
+ export CXXFLAGS="-Wno-array-bounds -Wno-uninitialized -Wno-stringop-overflow" && \
  echo "Building OSRM ${DOCKER_TAG}" && \
  git show --format="%H" | head -n1 > /opt/OSRM_GITSHA && \
  echo "Building OSRM gitsha $(cat /opt/OSRM_GITSHA)" && \

scripts/ci/windows-build.bat

@@ -62,7 +62,7 @@ SET test_region_ch=ch\monaco
 SET test_region_corech=corech\monaco
 SET test_region_mld=mld\monaco
 SET test_osm=%test_region%.osm.pbf
-COPY %PROJECT_DIR%\test\data\%test_region%.osm.pbf %test_osm% 
+COPY %PROJECT_DIR%\test\data\%test_region%.osm.pbf %test_osm%
 %CONFIGURATION%\osrm-extract.exe -p %PROJECT_DIR%\profiles\car.lua %test_osm%
 IF %ERRORLEVEL% NEQ 0 GOTO ERROR
 

src/extractor/extractor_callbacks.cpp

@@ -23,8 +23,6 @@
 #include <vector>
 
 #ifdef _MSC_VER
-#if (_MSC_VER >= 1928)
-#ifdef _DEBUG
 namespace osrm
 {
 namespace extractor
@@ -37,8 +35,6 @@ const ByEdgeOrByMeterValue::ValueByMeter ByEdgeOrByMeterValue::by_meter;
 } // namespace extractor
 } // namespace osrm
 #endif
-#endif
-#endif
 
 namespace osrm::extractor
 {