Defaulting to C++17 for building.

.circleci/config.yml

@@ -292,13 +292,13 @@ jobs:
           command: codecov --flags all --gcov-root build
       - store_artifacts: *artifacts_test_results
 
-  # Builds in C++17 mode and uses debug build in order to speed up.
+  # Builds in C++20 mode and uses debug build in order to speed up.
   # Do *NOT* store any artifacts or workspace as we don't run tests on this build.
-  b_ubu_cxx17:
+  b_ubu_cxx20:
     <<: *build_ubuntu1904
     environment:
       CMAKE_BUILD_TYPE: Debug
-      CMAKE_OPTIONS: -DCMAKE_TOOLCHAIN_FILE=cmake/toolchains/cxx17.cmake -DUSE_CVC4=OFF
+      CMAKE_OPTIONS: -DCMAKE_TOOLCHAIN_FILE=cmake/toolchains/cxx20.cmake -DUSE_CVC4=OFF
     steps:
       - checkout
       - run: *run_build
@@ -612,7 +612,7 @@ workflows:
       # build-only
       - b_docs: *workflow_trigger_on_tags
       - b_archlinux: *workflow_trigger_on_tags
-      - b_ubu_cxx17: *workflow_trigger_on_tags
+      - b_ubu_cxx20: *workflow_trigger_on_tags
       - b_ubu_ossfuzz: *workflow_trigger_on_tags
 
       # OS/X build and tests

.travis.yml

@@ -188,7 +188,7 @@ cache:
 
 install:
     - test $SOLC_INSTALL_DEPS_TRAVIS != On || (scripts/install_deps.sh)
-    - test "$TRAVIS_OS_NAME" != "linux" || (scripts/install_cmake.sh)
+    - test "$TRAVIS_OS_NAME" != "linux" || (sudo scripts/install_cmake.sh)
 
 before_script:
     # Disable tests unless run on the release branch, on tags or with daily cron

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5.0)
+cmake_minimum_required(VERSION 3.9.0)
 
 set(ETH_CMAKE_DIR   "${CMAKE_CURRENT_LIST_DIR}/cmake"   CACHE PATH "The the path to the cmake directory")
 list(APPEND CMAKE_MODULE_PATH ${ETH_CMAKE_DIR})
@@ -13,11 +13,6 @@ eth_policy()
 set(PROJECT_VERSION "0.5.12")
 project(solidity VERSION ${PROJECT_VERSION} LANGUAGES C CXX)
 
-if (${CMAKE_VERSION} VERSION_LESS "3.9.0")
-	# needed for the big endian test for older cmake versions
-	enable_language(C)
-endif()
-
 include(TestBigEndian)
 TEST_BIG_ENDIAN(IS_BIG_ENDIAN)
 if (IS_BIG_ENDIAN)

cmake/jsoncpp.cmake

@@ -15,9 +15,9 @@ set(JSONCPP_INCLUDE_DIR "${prefix}/include")
 # versions used in the CI runs.
 if(EMSCRIPTEN)
     # Do not include all flags in CMAKE_CXX_FLAGS for emscripten,
-    # but only use -std=c++14. Using all flags causes build failures
+    # but only use -std=c++17. Using all flags causes build failures
     # at the moment.
-    set(JSONCPP_CXX_FLAGS -std=c++14)
+    set(JSONCPP_CXX_FLAGS -std=c++17)
 else()
     set(JSONCPP_CXX_FLAGS ${CMAKE_CXX_FLAGS})
 endif()

cmake/toolchains/cxx17.cmake

@@ -1,4 +0,0 @@
-# Require C++17.
-set(CMAKE_CXX_STANDARD 17)
-set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
-set(CMAKE_CXX_EXTENSIONS OFF)

cmake/toolchains/cxx20.cmake

@@ -0,0 +1,4 @@
+# Require C++20.
+set(CMAKE_CXX_STANDARD 20) # This requires at least CMake 3.12 to understand this C++20 flag
+set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
+set(CMAKE_CXX_EXTENSIONS OFF)

cmake/toolchains/default.cmake

@@ -1,4 +1,4 @@
-# Require C++14.
-set(CMAKE_CXX_STANDARD 14)
+# Require C++17.
+set(CMAKE_CXX_STANDARD 17) # This requires at least CMake 3.8 to accept this C++17 flag.
 set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
 set(CMAKE_CXX_EXTENSIONS OFF)

docs/installing-solidity.rst

@@ -184,7 +184,7 @@ The following are dependencies for all builds of Solidity:
 +-----------------------------------+-------------------------------------------------------+
 | Software                          | Notes                                                 |
 +===================================+=======================================================+
-| `CMake`_ (version 3.5+)           | Cross-platform build file generator.                  |
+| `CMake`_ (version 3.9+)           | Cross-platform build file generator.                  |
 +-----------------------------------+-------------------------------------------------------+
 | `Boost`_  (version 1.65+)         | C++ libraries.                                        |
 +-----------------------------------+-------------------------------------------------------+

libdevcore/CMakeLists.txt

@@ -34,6 +34,6 @@ set(sources
 )
 
 add_library(devcore ${sources})
-target_link_libraries(devcore PUBLIC jsoncpp Boost::boost Boost::filesystem Boost::regex Boost::system Threads::Threads)
+target_link_libraries(devcore PUBLIC jsoncpp Boost::boost Boost::filesystem Boost::regex Boost::system)
 target_include_directories(devcore PUBLIC "${CMAKE_SOURCE_DIR}")
 add_dependencies(devcore solidity_BuildInfo.h)

scripts/install_cmake.sh

@@ -6,16 +6,18 @@
 
 set -e
 
-VERSION=3.7.1
-PREFIX=~/.local
+VERSION_MAJOR=3
+VERSION_MINOR=15
+VERSION_MICRO=2
+VERSION=$VERSION_MAJOR.$VERSION_MINOR.$VERSION_MICRO
+PREFIX="/usr/local"
 
 OS=$(uname -s)
 case $OS in
-Linux)  SHA256=7b4b7a1d9f314f45722899c0521c261e4bfab4a6b532609e37fef391da6bade2;;
-Darwin) SHA256=1851d1448964893fdc5a8c05863326119f397a3790e0c84c40b83499c7960267;;
+Linux)  SHA256=f8cbec2abc433938bd9378b129d1d288bb33b8b5a277afe19644683af6e32a59;;
+Darwin) SHA256=7ec056d641b8cbea98b220efdcc99da1991758a370063dcac3a0cd388d6b30b6;;
 esac
 
-
 BIN=$PREFIX/bin
 
 PATH=$PREFIX/bin:$PATH
@@ -24,7 +26,7 @@ if test -f $BIN/cmake && ($BIN/cmake --version | grep -q "$VERSION"); then
     echo "CMake $VERSION already installed in $BIN"
 else
     FILE=cmake-$VERSION-$OS-x86_64.tar.gz
-    URL=https://cmake.org/files/v3.7/$FILE
+    URL=https://cmake.org/files/v$VERSION_MAJOR.$VERSION_MINOR/$FILE
     ERROR=0
     TMPFILE=$(mktemp --tmpdir cmake-$VERSION-$OS-x86_64.XXXXXXXX.tar.gz)
     echo "Downloading CMake ($URL)..."