backport: merge bitcoin#24460, #27672, #27766, #28065, #30228, partial bitcoin#28349, #28579 (drop c++17 support)

.github/workflows/build.yml

@@ -75,15 +75,6 @@ jobs:
       container-path: ${{ needs.container.outputs.path }}
       depends-key: ${{ needs.depends-linux64.outputs.key }}
 
-  src-linux64_cxx20:
-    name: linux64_cxx20-build
-    uses: ./.github/workflows/build-src.yml
-    needs: [container, depends-linux64]
-    with:
-      build-target: linux64_cxx20
-      container-path: ${{ needs.container.outputs.path }}
-      depends-key: ${{ needs.depends-linux64.outputs.key }}
-
   src-linux64_fuzz:
     name: linux64_fuzz-build
     uses: ./.github/workflows/build-src.yml

.gitlab-ci.yml

@@ -235,15 +235,6 @@ linux64-build:
   variables:
     BUILD_TARGET: linux64
 
-linux64_cxx20-build:
-  extends:
-    - .build-template
-    - .skip-in-fast-mode-template
-  needs:
-    - x86_64-pc-linux-gnu
-  variables:
-    BUILD_TARGET: linux64_cxx20
-
 linux64_sqlite-build:
   extends:
     - .build-template

CMakeLists.txt

@@ -8,7 +8,7 @@
 cmake_minimum_required(VERSION 3.7)
 project(dash)
 
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
 
 include_directories(
         src

build-aux/m4/ax_cxx_compile_stdcxx.m4

@@ -10,14 +10,13 @@
 #
 #   Check for baseline language coverage in the compiler for the specified
 #   version of the C++ standard.  If necessary, add switches to CXX and
-#   CXXCPP to enable support.  VERSION may be '11' (for the C++11 standard),
-#   '14' (for the C++14 standard), '17' (for the C++17 standard) or
-#   '20' (for the C++20 standard)
+#   CXXCPP to enable support.  VERSION may be '11', '14', '17', or '20' for
+#   the respective C++ standard version.
 #
 #   The second argument, if specified, indicates whether you insist on an
 #   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
 #   -std=c++11).  If neither is specified, you get whatever works, with
-#   preference for an extended mode.
+#   preference for no added switch, and then for an extended mode.
 #
 #   The third argument, if specified 'mandatory' or if left unspecified,
 #   indicates that baseline support for the specified C++ standard is
@@ -36,25 +35,24 @@
 #   Copyright (c) 2015 Moritz Klammler <[email protected]>
 #   Copyright (c) 2016, 2018 Krzesimir Nowak <[email protected]>
 #   Copyright (c) 2019 Enji Cooper <[email protected]>
+#   Copyright (c) 2020 Jason Merrill <[email protected]>
+#   Copyright (c) 2021 Jörn Heusipp <[email protected]>
 #
 #   Copying and distribution of this file, with or without modification, are
 #   permitted in any medium without royalty provided the copyright notice
 #   and this notice are preserved.  This file is offered as-is, without any
 #   warranty.
 
-#serial 11
+#serial 14
 
 dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
 dnl  (serial version number 13).
 
-dnl  Modifications:
-dnl  Add support for C++20, with no new tests
-
 AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
   m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"],
         [$1], [14], [ax_cxx_compile_alternatives="14 1y"],
         [$1], [17], [ax_cxx_compile_alternatives="17 1z"],
-        [$1], [20], [ax_cxx_compile_alternatives="20 2a"],
+        [$1], [20], [ax_cxx_compile_alternatives="20"],
         [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
   m4_if([$2], [], [],
         [$2], [ext], [],
@@ -67,6 +65,16 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
   AC_LANG_PUSH([C++])dnl
   ac_success=no
 
+  m4_if([$2], [], [dnl
+    AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
+		   ax_cv_cxx_compile_cxx$1,
+      [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+        [ax_cv_cxx_compile_cxx$1=yes],
+        [ax_cv_cxx_compile_cxx$1=no])])
+    if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
+      ac_success=yes
+    fi])
+
   m4_if([$2], [noext], [], [dnl
   if test x$ac_success = xno; then
     for alternative in ${ax_cxx_compile_alternatives}; do
@@ -145,33 +153,28 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
 )
 
-
 dnl  Test body for checking C++14 support
 
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
 )
 
+dnl  Test body for checking C++17 support
+
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
 )
 
+dnl  Test body for checking C++20 support
 
-dnl Test body for checking C++20 support: R modification
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_20],
-#ifndef __cplusplus
-#error "This is not a C++ compiler"
-dnl value from 2020-01-14 draft, clang 11 has 202002L
-#elif __cplusplus < 201703L
-#error "This is not a C++20 compiler"
-#else
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
-#endif
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_20
 )
 
 
@@ -272,7 +275,7 @@ namespace cxx11
     }
 
     int
-    test(const int c, volatile int v) // 'volatile is deprecated in C++20'
+    test(const int c, volatile int v)
     {
       static_assert(is_same<int, decltype(0)>::value == true, "");
       static_assert(is_same<int, decltype(c)>::value == false, "");
@@ -970,3 +973,33 @@ namespace cxx17
 #endif  // __cplusplus < 201703L
 
 ]])
+
+
+dnl  Tests for new features in C++20
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_20], [[
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 202002L
+
+#error "This is not a C++20 compiler"
+
+#else
+
+#include <version>
+
+namespace cxx20
+{
+
+// As C++20 supports feature test macros in the standard, there is no
+// immediate need to actually test for feature availability on the
+// Autoconf side.
+
+}  // namespace cxx20
+
+#endif  // __cplusplus < 202002L
+
+]])

ci/dash/matrix.sh

@@ -22,8 +22,6 @@ elif [ "$BUILD_TARGET" = "linux64" ]; then
   source ./ci/test/00_setup_env_native_qt5.sh
 elif [ "$BUILD_TARGET" = "linux64_asan" ]; then
   source ./ci/test/00_setup_env_native_asan.sh
-elif [ "$BUILD_TARGET" = "linux64_cxx20" ]; then
-  source ./ci/test/00_setup_env_native_cxx20.sh
 elif [ "$BUILD_TARGET" = "linux64_fuzz" ]; then
   source ./ci/test/00_setup_env_native_fuzz.sh
 elif [ "$BUILD_TARGET" = "linux64_multiprocess" ]; then

ci/test/00_setup_env_native_fuzz.sh

@@ -10,7 +10,7 @@ export CONTAINER_NAME=ci_native_fuzz
 export PACKAGES="clang llvm python3 libevent-dev bsdmainutils libboost-dev"
 export DEP_OPTS="NO_UPNP=1 DEBUG=1"
 export CPPFLAGS="-DDEBUG_LOCKORDER -DARENA_DEBUG"
-export CXXFLAGS="-Werror -Wno-unused-command-line-argument -Wno-unused-value -Wno-deprecated-builtins"
+export CXXFLAGS="-Werror -Wno-unused-command-line-argument -Wno-unused-value -Wno-deprecated-builtins -Wno-deprecated-volatile"
 export PYZMQ=true
 export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false

ci/test/04_install.sh

@@ -85,7 +85,11 @@ if [ "$RUN_FUZZ_TESTS" = "true" ] || [ "$RUN_UNIT_TESTS" = "true" ] || [ "$RUN_U
   if [ ! -d "${DIR_QA_ASSETS}" ]; then
     DOCKER_EXEC git clone --depth=1 https://github.com/bitcoin-core/qa-assets "${DIR_QA_ASSETS}"
   fi
-
+  (
+    DOCKER_EXEC cd "${DIR_QA_ASSETS}"
+    DOCKER_EXEC echo "Using qa-assets repo from commit ..."
+    DOCKER_EXEC git log -1
+  )
   export DIR_FUZZ_IN=${DIR_QA_ASSETS}/fuzz_seed_corpus/
 fi
 

configure.ac

@@ -77,18 +77,8 @@ case $host in
   ;;
 esac
 
-AC_ARG_ENABLE([c++20],
-  [AS_HELP_STRING([--enable-c++20],
-  [enable compilation in c++20 mode (disabled by default)])],
-  [use_cxx20=$enableval],
-  [use_cxx20=no])
-
-dnl Require C++17 compiler (no GNU extensions)
-if test "$use_cxx20" = "no"; then
-  AX_CXX_COMPILE_STDCXX([17], [noext], [mandatory])
-else
-  AX_CXX_COMPILE_STDCXX([20], [noext], [mandatory])
-fi
+dnl Require C++20 compiler (no GNU extensions)
+AX_CXX_COMPILE_STDCXX([20], [noext], [mandatory])
 
 dnl Unless the user specified OBJCXX, force it to be the same as CXX. This ensures
 dnl that we get the same -std flags for both.

depends/Makefile

@@ -46,7 +46,7 @@ LTO ?=
 FALLBACK_DOWNLOAD_PATH ?= http://dash-depends-sources.s3-website-us-west-2.amazonaws.com
 
 C_STANDARD ?= c11
-CXX_STANDARD ?= c++17
+CXX_STANDARD ?= c++20
 
 BUILD = $(shell ./config.guess)
 HOST ?= $(BUILD)

depends/README.md

@@ -108,7 +108,7 @@ The following can be set when running make: `make FOO=bar`
 - `SDK_PATH`: Path where SDKs can be found (used by macOS)
 - `FALLBACK_DOWNLOAD_PATH`: If a source file can't be fetched, try here before giving up
 - `C_STANDARD`: Set the C standard version used. Defaults to `c11`.
-- `CXX_STANDARD`: Set the C++ standard version used. Defaults to `c++17`.
+- `CXX_STANDARD`: Set the C++ standard version used. Defaults to `c++20`.
 - `NO_QT`: Don't download/build/cache Qt and its dependencies
 - `NO_QR`: Don't download/build/cache packages needed for enabling qrencode
 - `NO_ZMQ`: Don't download/build/cache packages needed for enabling ZeroMQ

depends/packages/qt.mk

@@ -43,7 +43,7 @@ $(package)_config_opts_release += -silent
 $(package)_config_opts_debug = -debug
 $(package)_config_opts_debug += -optimized-tools
 $(package)_config_opts += -bindir $(build_prefix)/bin
-$(package)_config_opts += -c++std c++17
+$(package)_config_opts += -c++std c++2a
 $(package)_config_opts += -confirm-license
 $(package)_config_opts += -hostprefix $(build_prefix)
 $(package)_config_opts += -no-compile-examples

src/bitcoin-cli.cpp

@@ -556,7 +556,7 @@ class NetinfoRequestHandler : public BaseRequestHandler
                     peer.is_outbound ? "out" : "in",
                     ConnectionTypeForNetinfo(peer.conn_type),
                     peer.network,
-                    peer.transport_protocol_type.rfind('v', 0) == 0 ? peer.transport_protocol_type[1] : ' ',
+                    peer.transport_protocol_type.starts_with('v') == 0 ? peer.transport_protocol_type[1] : ' ',
                     PingTimeToString(peer.min_ping),
                     PingTimeToString(peer.ping),
                     peer.last_send ? ToString(time_now - peer.last_send) : "",

src/compat/assumptions.h

@@ -11,20 +11,6 @@
 #include <cstddef>
 #include <limits>
 
-// Assumption: We assume that the macro NDEBUG is not defined.
-// Example(s): We use assert(...) extensively with the assumption of it never
-//             being a noop at runtime.
-#if defined(NDEBUG)
-# error "Dash Core cannot be compiled without assertions."
-#endif
-
-// Assumption: We assume a C++17 (ISO/IEC 14882:2017) compiler (minimum requirement).
-// Example(s): We assume the presence of C++17 features everywhere :-)
-// ISO Standard C++17 [cpp.predefined]p1:
-// "The name __cplusplus is defined to the value 201703L when compiling a C++
-//  translation unit."
-static_assert(__cplusplus >= 201703L, "C++17 standard assumed");
-
 // Assumption: We assume the floating-point types to fulfill the requirements of
 //             IEC 559 (IEEE 754) standard.
 // Example(s): Floating-point division by zero in ConnectBlock, CreateTransaction

src/fs.h

@@ -8,7 +8,7 @@
 #include <tinyformat.h>
 
 #include <cstdio>
-#include <filesystem>
+#include <filesystem> // IWYU pragma: export
 #include <iomanip>
 #include <ios>
 #include <ostream>

src/net.cpp

@@ -1119,16 +1119,9 @@ constexpr std::array<std::string_view, 256> V2ShortIDs() {
     static_assert(std::size(V2_DASH_IDS) <= 128);
 
     std::array<std::string_view, 256> ret{};
-    for (size_t idx{0}; idx < std::size(ret); idx++) {
-        if (idx < 128 && idx < std::size(V2_BITCOIN_IDS)) {
-            ret[idx] = V2_BITCOIN_IDS[idx];
-        } else if (idx >= 128 && idx - 128 < std::size(V2_DASH_IDS)) {
-            ret[idx] = V2_DASH_IDS[idx - 128];
-        } else {
-            ret[idx] = "";
-        }
-    }
-
+    std::fill(ret.begin(), ret.end(), "");
+    std::copy(V2_BITCOIN_IDS.begin(), V2_BITCOIN_IDS.end(), ret.begin());
+    std::copy(V2_DASH_IDS.begin(), V2_DASH_IDS.end(), ret.begin() + 128);
     return ret;
 }
 

src/net_processing.cpp

@@ -35,7 +35,7 @@
 #include <index/txindex.h>
 #include <txmempool.h>
 #include <txorphanage.h>
-#include <util/check.h> // For NDEBUG compile time check
+#include <util/check.h>
 #include <util/system.h>
 #include <util/strencodings.h>
 #include <util/trace.h>

src/test/fuzz/addrman.cpp

@@ -45,7 +45,7 @@ void initialize_addrman()
     return NetGroupManager(asmap);
 }
 
-FUZZ_TARGET_INIT(data_stream_addr_man, initialize_addrman)
+FUZZ_TARGET(data_stream_addr_man, .init = initialize_addrman)
 {
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
     CDataStream data_stream = ConsumeDataStream(fuzzed_data_provider);
@@ -232,7 +232,7 @@ class AddrManDeterministic : public AddrMan
     }
 };
 
-FUZZ_TARGET_INIT(addrman, initialize_addrman)
+FUZZ_TARGET(addrman, .init = initialize_addrman)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     SetMockTime(ConsumeTime(fuzzed_data_provider));
@@ -313,7 +313,7 @@ FUZZ_TARGET_INIT(addrman, initialize_addrman)
 }
 
 // Check that serialize followed by unserialize produces the same addrman.
-FUZZ_TARGET_INIT(addrman_serdeser, initialize_addrman)
+FUZZ_TARGET(addrman_serdeser, .init = initialize_addrman)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     SetMockTime(ConsumeTime(fuzzed_data_provider));

src/test/fuzz/banman.cpp

@@ -40,7 +40,7 @@ static bool operator==(const CBanEntry& lhs, const CBanEntry& rhs)
            lhs.nBanUntil == rhs.nBanUntil;
 }
 
-FUZZ_TARGET_INIT(banman, initialize_banman)
+FUZZ_TARGET(banman, .init = initialize_banman)
 {
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
     SetMockTime(ConsumeTime(fuzzed_data_provider));

src/test/fuzz/bip324.cpp

@@ -19,7 +19,7 @@ void initialize_bip324()
     SelectParams(CBaseChainParams::MAIN);
 }
 
-FUZZ_TARGET_INIT(bip324_cipher_roundtrip, initialize_bip324)
+FUZZ_TARGET(bip324_cipher_roundtrip, .init = initialize_bip324)
 {
     // Test that BIP324Cipher's encryption and decryption agree.