CMakeLists.txt

cmake_minimum_required(VERSION 3.15)
project(hoard
  VERSION 3.2
  LANGUAGES CXX
  DESCRIPTION "High-performance scalable memory allocator"
)

#
# ─── OPTIONS ──────────────────────────────────────────────────────────
#

set(CMAKE_CXX_STANDARD 23)
set(CMAKE_CXX_STANDARD_REQUIRED OFF)

# Add cmake modules path
list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")

if(APPLE)
  set(CMAKE_OSX_ARCHITECTURES arm64 arm64e x86_64)
endif()

# Generate position-independent code; required for shared libraries on many platforms
set(CMAKE_POSITION_INDEPENDENT_CODE ON)

# Note: alloc8 handles version scripts, visibility flags, and compiler options

#
# ─── INCLUDE DIRECTORIES ──────────────────────────────────────────────
#

include_directories(
  ${PROJECT_SOURCE_DIR}
  ${PROJECT_SOURCE_DIR}/src/include
  ${PROJECT_SOURCE_DIR}/src/include/hoard
  ${PROJECT_SOURCE_DIR}/src/include/superblocks
  ${PROJECT_SOURCE_DIR}/src/include/util
)

include(FetchContent)
FetchContent_Declare(
  Heap-Layers
  GIT_REPOSITORY https://github.com/emeryberger/Heap-Layers.git
  GIT_TAG        master
)
FetchContent_MakeAvailable(Heap-Layers)
include_directories(${heap-layers_SOURCE_DIR})

# Allocation-free printf (compiled directly into Hoard, not as a library)
FetchContent_Declare(
  printf
  GIT_REPOSITORY https://github.com/emeryberger/printf.git
  GIT_TAG        master
  GIT_SHALLOW    TRUE
)
FetchContent_MakeAvailable(printf)
include_directories(${printf_SOURCE_DIR})

# alloc8 - generic allocator interposition library for all platforms
FetchContent_Declare(
  alloc8
  GIT_REPOSITORY https://github.com/emeryberger/alloc8.git
  GIT_TAG        main
  GIT_SHALLOW    TRUE
)
FetchContent_MakeAvailable(alloc8)
include_directories(${alloc8_SOURCE_DIR}/include)

set(UNIX_SOURCES
  src/source/unixtls.cpp
  src/source/libhoard.cpp
  ${printf_SOURCE_DIR}/printf.cpp
  ${ALLOC8_INTERPOSE_SOURCES}
)

set(MACOS_SOURCES
  src/source/mactls.cpp
  src/source/libhoard.cpp
  ${printf_SOURCE_DIR}/printf.cpp
  ${ALLOC8_INTERPOSE_SOURCES}
)

set(WINDOWS_SOURCES
  src/source/wintls.cpp
  src/source/libhoard.cpp
  ${printf_SOURCE_DIR}/printf.cpp
  ${ALLOC8_INTERPOSE_SOURCES}
)

# Hoard never reads alloc8's caller-return-address hint (alloc8_caller_ra), and
# it is a thread_local store on EVERY malloc and free -- ~15% of the allocation
# fast path. Opt out of it. (Harmlessly ignored by alloc8 versions that predate
# the flag; the symbol is still defined either way.)
add_definitions(-DALLOC8_NO_CALLER_RA)

if(WIN32)
  #
  # ─── WINDOWS BUILD ───────────────────────────────────────────────────
  # alloc8 handles Detours fetching/building internally
  # ALLOC8_NO_DLLMAIN: Hoard provides its own DllMain in wintls.cpp
  #
  set(HOARD_SOURCES ${WINDOWS_SOURCES})
  add_definitions(-D_CRT_SECURE_NO_WARNINGS -DWIN32_LEAN_AND_MEAN -DALLOC8_NO_DLLMAIN)
  # Compile-time inline ownership hook for alloc8's Windows wrapper:
  # replaces SEH-probe foreign-pointer detection (which dereferences
  # masked addresses and, after init, skipped checking entirely) with
  # Hoard's O(1) ownership map. See hoardownsinline.h.
  add_definitions(-DALLOC8_XXOWNS_INLINE_HEADER=\"hoardownsinline.h\")

elseif(APPLE)
  set(HOARD_SOURCES ${MACOS_SOURCES})
  add_compile_options(-ftls-model=initial-exec -ftemplate-depth=1024)
  # Compile-time inline ownership hook for alloc8: the predicate in
  # hoardownsinline.h (backed by Hoard's superblock ownership map) inlines
  # directly into alloc8's replace_free/replace_realloc/malloc_size hot
  # paths. Harmlessly ignored by alloc8 versions without the hook (the
  # runtime xxowns() hook in libhoard.cpp then applies instead).
  add_definitions(-DALLOC8_XXOWNS_INLINE_HEADER=\"hoardownsinline.h\")
else()
  set(HOARD_SOURCES ${UNIX_SOURCES})
endif()

# NDEBUG is deliberately NOT forced here. The Release and RelWithDebInfo
# configs already define it (CMAKE_CXX_FLAGS_<CONFIG>), so adding it
# unconditionally changed nothing for them while making it impossible to
# ever get an assertion-checked build: the asserts throughout the heap
# layers (isValid(), alignment, size-class invariants) were compiled out
# in every configuration, including Debug. Leave it to the config.

# Force Release build type for optimal performance (memory allocators need aggressive inlining)
if(NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE Release CACHE STRING "Build type" FORCE)
endif()

# NOTE: Link-Time Optimization (LTO) DISABLED on Windows ARM64 - causes 6x slowdown!
# MSVC's ARM64 LTO codegen produces significantly slower code for memory allocators.
if(NOT WIN32)
  include(CheckIPOSupported)
  # Hoard is C++ only (project LANGUAGES CXX); scope the check to CXX so that
  # a C compiler pulled in by a dependency (which CMake's IPO table may not
  # recognize) doesn't disable LTO for our C++ targets.
  check_ipo_supported(RESULT ipo_supported OUTPUT ipo_error LANGUAGES CXX)
  if(ipo_supported)
    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
    message(STATUS "LTO enabled")
  else()
    message(STATUS "LTO not supported: ${ipo_error}")
  endif()
else()
  message(STATUS "LTO disabled on Windows (causes ARM64 slowdown)")
endif()

# Enable maximum optimization for MSVC
if(MSVC)
  # /O2 = maximize speed, /Ob2 = inline any suitable function, /Oi = enable intrinsics
  # /Ot = favor fast code
  # NOTE: /GL (whole program optimization) DISABLED - causes 6x slowdown on ARM64!
  # The MSVC ARM64 LTO codegen appears to produce significantly slower code.
  set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Ob2 /Oi /Ot")
  set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} /Ob2 /Oi /Ot")
  # NOTE: /LTCG disabled since /GL is disabled
endif()

add_library(hoard SHARED ${HOARD_SOURCES})

# Link with alloc8 interposition library (handles platform-specific linking)
target_link_libraries(hoard PRIVATE alloc8::interpose)

# Platform-specific additional settings
if(WIN32)
  # Export DetourFinishHelperProcess at ordinal #1 (required for withdll.exe)
  target_link_options(hoard PRIVATE "/export:DetourFinishHelperProcess,@1,NONAME")

  # Disable some MSVC warnings
  target_compile_options(hoard PRIVATE /W3 /WX-)

  # Set Windows-specific properties
  set_target_properties(hoard PROPERTIES
    OUTPUT_NAME "hoard"
    RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}"
  )
else()
  set_target_properties(hoard PROPERTIES OUTPUT_NAME "hoard")
endif()

target_compile_definitions(hoard
    PRIVATE
    _REENTRANT=1
)

#
# ─── EXPORT AND INSTALL ────────────────────────────────────────────────
#

include(CMakePackageConfigHelpers)
include(GNUInstallDirs)

# Set up the export name
set(HOARD_EXPORT_NAME HoardTargets)

# Install the library with export
install(TARGETS hoard
  EXPORT ${HOARD_EXPORT_NAME}
  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

# Export target with namespace
install(EXPORT ${HOARD_EXPORT_NAME}
  FILE HoardTargets.cmake
  NAMESPACE Hoard::
  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Hoard
)

# Create an alias for use from build tree
add_library(Hoard::Hoard ALIAS hoard)

# Set export name to maintain consistent Hoard::Hoard naming after installation
set_target_properties(hoard PROPERTIES EXPORT_NAME Hoard)

# Configure the package config file
configure_package_config_file(
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/HoardConfig.cmake.in"
  "${CMAKE_CURRENT_BINARY_DIR}/HoardConfig.cmake"
  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Hoard
)

# Generate version file
write_basic_package_version_file(
  "${CMAKE_CURRENT_BINARY_DIR}/HoardConfigVersion.cmake"
  VERSION ${PROJECT_VERSION}
  COMPATIBILITY SameMajorVersion
)

# Install the config files
install(FILES
  "${CMAKE_CURRENT_BINARY_DIR}/HoardConfig.cmake"
  "${CMAKE_CURRENT_BINARY_DIR}/HoardConfigVersion.cmake"
  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Hoard
)

#
# ─── EXTERNAL ALLOCATORS (for benchmarking) ────────────────────────────
#
# Build external allocators for comparison benchmarking.
# Enable with: -DBUILD_JEMALLOC=ON -DBUILD_MIMALLOC=ON -DBUILD_TCMALLOC=ON
# Or all at once: -DBUILD_ALL_ALLOCATORS=ON
#
if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/allocators/CMakeLists.txt")
  add_subdirectory(allocators)
endif()