CMake: Add GPERF option

This option links the tcmalloc and gperf memory profiler.

It can then be used to memory-profile individual sections of the app.

On Ubuntu, the package that provides the profiler is
`libgoogle-perftools-dev`.

CMake/FindGperftools.cmake

@@ -0,0 +1,53 @@
+# Based on https://github.com/baidu/braft/blob/e7776cd03ccc04f18d0f0911200617a89ac3cdf0/cmake/FindGperftools.cmake
+
+# Tries to find Gperftools.
+#
+# Usage of this module as follows:
+#
+#     find_package(Gperftools)
+#
+# Variables used by this module, they can change the default behaviour and need
+# to be set before calling find_package:
+#
+#  Gperftools_ROOT_DIR  Set this variable to the root installation of
+#                       Gperftools if the module has problems finding
+#                       the proper installation path.
+#
+# Variables defined by this module:
+#
+#  GPERFTOOLS_FOUND              System has Gperftools libs/headers
+#  GPERFTOOLS_LIBRARIES          The Gperftools libraries (tcmalloc & profiler)
+#  GPERFTOOLS_INCLUDE_DIR        The location of Gperftools headers
+
+find_library(GPERFTOOLS_TCMALLOC
+  NAMES tcmalloc
+  HINTS ${Gperftools_ROOT_DIR}/lib)
+
+find_library(GPERFTOOLS_PROFILER
+  NAMES profiler
+  HINTS ${Gperftools_ROOT_DIR}/lib)
+
+find_library(GPERFTOOLS_TCMALLOC_AND_PROFILER
+  NAMES tcmalloc_and_profiler
+  HINTS ${Gperftools_ROOT_DIR}/lib)
+
+find_path(GPERFTOOLS_INCLUDE_DIR
+  NAMES gperftools/heap-profiler.h
+  HINTS ${Gperftools_ROOT_DIR}/include)
+
+set(GPERFTOOLS_LIBRARIES ${GPERFTOOLS_TCMALLOC_AND_PROFILER})
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(
+  Gperftools
+  DEFAULT_MSG
+  GPERFTOOLS_LIBRARIES
+  GPERFTOOLS_INCLUDE_DIR)
+
+mark_as_advanced(
+  Gperftools_ROOT_DIR
+  GPERFTOOLS_TCMALLOC
+  GPERFTOOLS_PROFILER
+  GPERFTOOLS_TCMALLOC_AND_PROFILER
+  GPERFTOOLS_LIBRARIES
+  GPERFTOOLS_INCLUDE_DIR)

CMakeLists.txt

@@ -7,6 +7,7 @@ include(CMake/genex.cmake)
 DEBUG_OPTION(ASAN "Enable address sanitizer")
 DEBUG_OPTION(UBSAN "Enable undefined behaviour sanitizer")
 DEBUG_OPTION(DEBUG "Enable debug mode in engine")
+option(GPERF "Build with GPerfTools profiler" OFF)
 option(DISABLE_LTO "Disable link-time optimization (by default enabled in release mode)" OFF)
 option(PIE "Generate position-independent code" OFF)
 option(DIST "Dynamically link only glibc and SDL2" OFF)
@@ -422,6 +423,10 @@ if(RUN_TESTS)
   gtest_add_tests(${BIN_TARGET} "" AUTO)
 endif()
 
+if(GPERF)
+  find_package(Gperftools REQUIRED)
+endif()
+
 target_include_directories(devilution PUBLIC Source SourceS ${CMAKE_CURRENT_BINARY_DIR})
 target_include_directories(${BIN_TARGET} PRIVATE
   SourceS
@@ -462,6 +467,7 @@ foreach(
   PREFILL_PLAYER_NAME
   DISABLE_STREAMING_MUSIC
   DISABLE_STREAMING_SOUNDS
+  GPERF
 )
 if(${def_name})
   list(APPEND def_list ${def_name})
@@ -600,6 +606,10 @@ foreach(target devilution ${BIN_TARGET} SourceS)
   endif()
 
   target_compile_definitions(${target} PRIVATE ${def_list})
+
+  if (GPERF)
+    target_link_libraries(${target} PRIVATE ${GPERFTOOLS_LIBRARIES})
+  endif()
 endforeach(target)
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND NOT HAIKU AND NOT VITA)