Merge bitcoin/bitcoin#33842: build: Bump g++ minimum supported version to 12

fa9f29a4a7 doc: Recommend latest Debian stable or Ubuntu LTS (MarcoFalke)
fa1711ee0d doc: Add GCC-12 min release notes (MarcoFalke)
faa8be75c9 ci: Enable experimental kernel stuff in G++-12 task (previous releases) (MarcoFalke)
fabce97b30 test: Remove gccbug_90348 test case (MarcoFalke)
fa3854e432 test: Remove unused fs::create_directories test (MarcoFalke)
fa9dacdbde util: [refactor] Remove unused create_directories workaround (MarcoFalke)
fa807f78ae build: Bump g++ minimum supported version to 12 (MarcoFalke)

Pull request description:

  All supported operating systems that previously came with at least g++-11, also come with at least g++-12, so bumping the minimum should be fine.

  For reference:

  * https://packages.ubuntu.com/jammy/g++-12
  * https://packages.ubuntu.com/noble/g++ (g++-13)
  * https://packages.debian.org/bookworm/g++ (g++-12)
  * FreeBSD Ports ship a recent GCC
  * RHEL-based 8, and 9 ship with g++-14 via appstream (`dnf install gcc-toolset-14` -> `/opt/rh/gcc-toolset-14/`)
  * RHEL-based 10 ships with g++ (14 by default)
  * OpenSuse Leap and Tumbleweed ship with g++ 15 https://software.opensuse.org/package/gcc15-c++

  Obviously, downloading pre-compiled releases or compiling previous release branches is unaffected by this change.

ACKs for top commit:
  janb84:
    re-ACK fa9f29a4a7
  TheCharlatan:
    Re-ACK fa9f29a4a7
  hebasto:
    ACK fa9f29a4a7.

Tree-SHA512: ce14ecf78ccfe4f221dcbc9147dcfc00c0512b23a6fcda5ba71b62b4f5d39a5139f083d035113f189bfbd396d485e1ebc626a9a16b6fa0b74fd95aed2041c841

.github/workflows/ci.yml

@@ -510,7 +510,7 @@ jobs:
             timeout-minutes: 240
             file-env: './ci/test/00_setup_env_native_fuzz_with_valgrind.sh'
 
-          - name: 'previous releases, depends DEBUG'
+          - name: 'previous releases'
             cirrus-runner: 'ghcr.io/cirruslabs/ubuntu-runner-amd64:24.04-md'
             fallback-runner: 'ubuntu-24.04'
             timeout-minutes: 120

CMakeLists.txt

@@ -493,8 +493,8 @@ try_append_cxx_flags("-fmacro-prefix-map=A=B" TARGET core_interface SKIP_LINK
   IF_CHECK_PASSED "-fmacro-prefix-map=${PROJECT_SOURCE_DIR}/src=."
 )
 
-# Currently all versions of gcc are subject to a class of bugs, see the
-# gccbug_90348 test case (only reproduces on GCC 11 and earlier) and
+# GCC versions 13.2 (and earlier) are subject to a class of bugs, see
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90348 and the meta bug
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111843. To work around that, set
 # -fstack-reuse=none for all gcc builds. (Only gcc understands this flag).
 try_append_cxx_flags("-fstack-reuse=none" TARGET core_interface)

ci/test/00_setup_env_native_previous_releases.sh

@@ -8,15 +8,16 @@ export LC_ALL=C.UTF-8
 
 export CONTAINER_NAME=ci_native_previous_releases
 export CI_IMAGE_NAME_TAG="mirror.gcr.io/ubuntu:22.04"
-# Use minimum supported python3.10 and gcc-11, see doc/dependencies.md
-export PACKAGES="gcc-11 g++-11 python3-zmq"
-export DEP_OPTS="CC=gcc-11 CXX=g++-11"
+# Use minimum supported python3.10 and gcc-12, see doc/dependencies.md
+export PACKAGES="gcc-12 g++-12 python3-zmq"
+export DEP_OPTS="CC=gcc-12 CXX=g++-12"
 export TEST_RUNNER_EXTRA="--previous-releases --coverage --extended --exclude feature_dbcrash"  # Run extended tests so that coverage does not fail, but exclude the very slow dbcrash
 export GOAL="install"
 export CI_LIMIT_STACK_SIZE=1
 export DOWNLOAD_PREVIOUS_RELEASES="true"
 export BITCOIN_CONFIG="\
- -DWITH_ZMQ=ON -DBUILD_GUI=ON -DREDUCE_EXPORTS=ON \
+ --preset=dev-mode \
+ -DREDUCE_EXPORTS=ON \
  -DCMAKE_BUILD_TYPE=Debug \
  -DCMAKE_C_FLAGS='-funsigned-char' \
  -DCMAKE_C_FLAGS_DEBUG='-g2 -O2' \

doc/build-unix.md

@@ -46,10 +46,14 @@ Finally, clang (often less resource hungry) can be used instead of gcc, which is
 
 #### Dependency Build Instructions
 
-Build requirements:
+Build requirements for the latest Debian "stable" release, or the latest Ubuntu LTS release:
 
     sudo apt-get install build-essential cmake pkgconf python3
 
+For Debian "oldstable", or earlier Ubuntu LTS releases, you may need to pick a
+later compiler version, according to the [dependencies](/doc/dependencies.md)
+documentation.
+
 Now, you can either build from self-compiled [depends](#dependencies) or install the required dependencies:
 
     sudo apt-get install libevent-dev libboost-dev

doc/dependencies.md

@@ -11,7 +11,7 @@ Bitcoin Core requires one of the following compilers.
 | Dependency | Minimum required |
 | --- | --- |
 | [Clang](https://clang.llvm.org) | [17.0](https://github.com/bitcoin/bitcoin/pull/33555) |
-| [GCC](https://gcc.gnu.org) | [11.1](https://github.com/bitcoin/bitcoin/pull/29091) |
+| [GCC](https://gcc.gnu.org) | [12.1](https://github.com/bitcoin/bitcoin/pull/33842) |
 
 ## Required
 

doc/release-notes-33842.md

@@ -0,0 +1,4 @@
+Build System
+------------
+
+- The minimum supported GCC compiler version has been raised to 12.1 (#33842).

src/test/CMakeLists.txt

@@ -34,7 +34,6 @@ add_executable(test_bitcoin
   coinscachepair_tests.cpp
   coinstatsindex_tests.cpp
   common_url_tests.cpp
-  compilerbug_tests.cpp
   compress_tests.cpp
   crypto_tests.cpp
   cuckoocache_tests.cpp

src/test/compilerbug_tests.cpp

@@ -1,42 +0,0 @@
-// Copyright (c) 2019-2021 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#include <boost/test/unit_test.hpp>
-
-BOOST_AUTO_TEST_SUITE(compilerbug_tests)
-
-#if defined(__GNUC__)
-// This block will also be built under clang, which is fine (as it supports noinline)
-void __attribute__ ((noinline)) set_one(unsigned char* ptr)
-{
-    *ptr = 1;
-}
-
-int __attribute__ ((noinline)) check_zero(unsigned char const* in, unsigned int len)
-{
-    for (unsigned int i = 0; i < len; ++i) {
-        if (in[i] != 0) return 0;
-    }
-    return 1;
-}
-
-void set_one_on_stack() {
-    unsigned char buf[1];
-    set_one(buf);
-}
-
-BOOST_AUTO_TEST_CASE(gccbug_90348) {
-    // Test for GCC bug 90348. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90348
-    for (int i = 0; i <= 4; ++i) {
-        unsigned char in[4];
-        for (int j = 0; j < i; ++j) {
-            in[j] = 0;
-            set_one_on_stack(); // Apparently modifies in[0]
-        }
-        BOOST_CHECK(check_zero(in, i));
-    }
-}
-#endif
-
-BOOST_AUTO_TEST_SUITE_END()

src/test/fs_tests.cpp

@@ -139,28 +139,4 @@ BOOST_AUTO_TEST_CASE(rename)
     fs::remove(path2);
 }
 
-#ifndef __MINGW64__ // no symlinks on mingw
-BOOST_AUTO_TEST_CASE(create_directories)
-{
-    // Test fs::create_directories workaround.
-    const fs::path tmpfolder{m_args.GetDataDirBase()};
-
-    const fs::path dir{tmpfolder / "a"};
-    fs::create_directory(dir);
-    BOOST_CHECK(fs::exists(dir));
-    BOOST_CHECK(fs::is_directory(dir));
-    BOOST_CHECK(!fs::create_directories(dir));
-
-    const fs::path symlink{tmpfolder / "b"};
-    fs::create_directory_symlink(dir, symlink);
-    BOOST_CHECK(fs::exists(symlink));
-    BOOST_CHECK(fs::is_symlink(symlink));
-    BOOST_CHECK(fs::is_directory(symlink));
-    BOOST_CHECK(!fs::create_directories(symlink));
-
-    fs::remove(symlink);
-    fs::remove(dir);
-}
-#endif // __MINGW64__
-
 BOOST_AUTO_TEST_SUITE_END()

src/util/fs.h

@@ -185,29 +185,6 @@ static inline path PathFromString(const std::string& string)
     return std::filesystem::path(string);
 #endif
 }
-
-/**
- * Create directory (and if necessary its parents), unless the leaf directory
- * already exists or is a symlink to an existing directory.
- * This is a temporary workaround for an issue in libstdc++ that has been fixed
- * upstream [PR101510].
- * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101510
- */
-static inline bool create_directories(const std::filesystem::path& p)
-{
-    if (std::filesystem::is_symlink(p) && std::filesystem::is_directory(p)) {
-        return false;
-    }
-    return std::filesystem::create_directories(p);
-}
-
-/**
- * This variant is not used. Delete it to prevent it from accidentally working
- * around the workaround. If it is needed, add a workaround in the same pattern
- * as above.
- */
-bool create_directories(const std::filesystem::path& p, std::error_code& ec) = delete;
-
 } // namespace fs
 
 /** Bridge operations to C stdio */