Cmake refactoring (#1551)

* Ignore clangd .cache directory

With the in-tree build, clangd likes to put its cache files inside of
/.cache. Thus, put the directory to .gitignore.

* Remove redundant cmake_minimum_required calls

There is no need to repeat the same information in all subprojects, the
call in the root CMakeLists.txt is more than enough.

* Bump minimum CMake version to 3.16

This avoids deprecation warnings on newer CMake versions. 3.16 was
chosen as a version easily available on Ubuntu 20.04 -- the oldest
distributive we support.

* Do not automatically add -stdlib=libc++ when sanitizers are requested

In my experience, adding -stdlib=libc++ during compilation of a project
with C++ dependencies which are not consistently using libc++ never
works. In this particular case, modern enough stdlibc++ works just fine
when compiled with Clang and sanitizers, while using libc++ results in
obscure linker errors.

* Do not fall back to -O2 if CMAKE_BUILD_TYPE == RelWithDebInfo

* Use CMAKE_{C,CXX}_COMPILER_LAUNCHER for enabling ccache

Additionally, if user has already specified either of these two
variables, don't override their choices.

As per documentation, RULE_LAUNCH_{COMPILE,LINK} are only supposed to be
used in internal CMake code. More importantly, the previous approach
appended ccache two times if CMAKE_CXX_COMPILER_LAUNCHER was provided in
command line or via an environment variable.

* Remove unused crypto/openssl/digest.h

Author: DanShaders

.gitignore

@@ -11,6 +11,7 @@ crypto/smartcont/auto/
 test/regression-tests.cache/
 *.swp
 **/*build*/
+.cache
 .idea
 .vscode
 .DS_Store

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.16 FATAL_ERROR)
 
 project(TON VERSION 0.5 LANGUAGES C CXX)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
@@ -159,6 +159,9 @@ if (TON_USE_ROCKSDB)
   set(FAIL_ON_WARNINGS OFF CACHE BOOL "fail on warnings")
   message("Add rocksdb")
   add_subdirectory(third-party/rocksdb EXCLUDE_FROM_ALL)
+  # Broken CMake in rocksdb alters properties it has no business changing.
+  set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE)
+  set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK)
 endif()
 
 option(USE_COROUTINES "experimental support of coroutines" OFF)
@@ -188,11 +191,12 @@ include(BuildSECP256K1)
 
 # Configure CCache if available
 find_program(CCACHE_FOUND ccache)
-#set(CCACHE_FOUND 0)
 if (CCACHE_FOUND)
-  message(STATUS "Found ccache")
-  set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache)
-  set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
+  if (NOT DEFINED CMAKE_C_COMPILER_LAUNCHER AND NOT DEFINED CMAKE_CXX_COMPILER_LAUNCHER)
+    message(STATUS "Using ccache")
+    set(CMAKE_C_COMPILER_LAUNCHER ccache)
+    set(CMAKE_CXX_COMPILER_LAUNCHER ccache)
+  endif()
 else()
   message(STATUS "Could NOT find ccache")
 endif()
@@ -341,6 +345,14 @@ add_cxx_compiler_flag("-Qunused-arguments")
 add_cxx_compiler_flag("-Wno-unused-private-field")
 add_cxx_compiler_flag("-Wno-redundant-move")
 
+if (GCC OR CLANG)
+  if (CMAKE_BUILD_TYPE MATCHES "RelWithDebInfo")
+    # For historical reasons, CMake falls back to -O2 optimization level when CMAKE_BUILD_TYPE is
+    # set to RelWithDebInfo.
+    add_compile_options(-O3)
+  endif()
+endif()
+
 #add_cxx_compiler_flag("-Wno-unused-function")
 #add_cxx_compiler_flag("-Wno-unused-variable")
 #add_cxx_compiler_flag("-Wno-shorten-64-to-32")
@@ -351,22 +363,13 @@ if (CLANG)
   #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
 endif()
 if (TON_USE_ASAN)
-  if (CLANG)
-    add_cxx_compiler_flag("-stdlib=libc++")
-  endif()
   add_cxx_compiler_flag("-fsanitize=address")
   add_definitions(-DTD_USE_ASAN=1)
 endif()
 if (TON_USE_TSAN)
-  if (CLANG)
-    add_cxx_compiler_flag("-stdlib=libc++")
-  endif()
   add_cxx_compiler_flag("-fsanitize=thread")
 endif()
 if (TON_USE_UBSAN)
-  if (CLANG)
-    add_cxx_compiler_flag("-stdlib=libc++")
-  endif()
   add_cxx_compiler_flag("-fsanitize=undefined")
 endif()
 #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=thread")

adnl/CMakeLists.txt

@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
 #BEGIN internal
 if (NOT TON_ONLY_TONLIB)
 set(ADNL_HEADERS

blockchain-explorer/CMakeLists.txt

@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
 option(NIX "Use \"ON\" for a static build." OFF)
 
 set(BLOCHAIN_EXPLORER_SOURCE

catchain/CMakeLists.txt

@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
 if (NOT OPENSSL_FOUND)
   find_package(OpenSSL REQUIRED)
 endif()

common/CMakeLists.txt

@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
 set(COMMON_SOURCE
   checksum.h
   errorcode.h 

create-hardfork/CMakeLists.txt

@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
 if (NOT OPENSSL_FOUND)
   find_package(OpenSSL REQUIRED)
 endif()

crypto/CMakeLists.txt

@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
 if (NOT OPENSSL_FOUND)
   find_package(OpenSSL REQUIRED)
 endif()

crypto/openssl/digest.h

@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
 if (NOT OPENSSL_FOUND)
   find_package(OpenSSL REQUIRED)
 endif()