From 318c7263d0395c6b590b67231960457d23a732e7 Mon Sep 17 00:00:00 2001 From: "Wladimir J. van der Laan" Date: Fri, 12 Feb 2021 10:56:51 +0100 Subject: [PATCH] Merge #19522: build: fix building libconsensus with reduced exports for Darwin targets MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit de4238f92f4c067f099663f68d9772105de81d75 build: consolidate reduced export checks (fanquake) 012bdec1b7df01906566a6526e56f27d57d1653b build: add building libconsensus to end-of-configure output (fanquake) 8f360e349e365870b40a6873917c81de714ae41a build: remove ax_gcc_func_attribute macro (fanquake) f054a089ecfbdc4732e6f705a10e93189074f41c build: remove AX_GCC_FUNC_ATTRIBUTE test for dllimport (fanquake) 7cd0a696643a824ab6f6911278f116f01c5af662 build: test for __declspec(dllexport) in configure (fanquake) 1624e17b5430dfe808bb3b1b79dfa53bf45aa053 build: remove duplicate visibility attribute detection (fanquake) Pull request description: Darwin targets do not have a `protected` visibility function attribute, see [LLVM explanation](https://github.com/llvm/llvm-project/blob/8e9a505139fbef7d2e6e9d0adfe1efc87326f9ef/clang/lib/Basic/Targets/OSTargets.h#L131). This means that the `AX_GCC_FUNC_ATTRIBUTE` check for `visibility` fails: ```bash configure:24513: checking for __attribute__((visibility)) configure:24537: g++ -std=c++11 -o conftest -g -O2 -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS -DMAC_OSX -DOBJC_OLD_DISPATCH_PROTOTYPES=0 -Wl,-headerpad_max_install_names conftest.cpp >&5 conftest.cpp:35:56: warning: target does not support 'protected' visibility; using 'default' [-Wunsupported-visibility] int foo_pro( void ) __attribute__((visibility("protected"))); ^ 1 warning generated. configure:24537: $? = 0 configure:24550: result: no ``` This leads to `EXPORT_SYMBOL` being [defined to nothing](https://github.com/bitcoin/bitcoin/blob/f4de89edfa8be4501534fec0c662c650a4ce7ef2/src/script/bitcoinconsensus.h#L29), as `HAVE_FUNC_ATTRIBUTE_VISIBILITY` is not defined, and when building with reduced exports, you end up with a libbitcoinconsensus.dylib that doesn't export any `_bitcoinconsensus_*` symbols. ```bash ➜ git:(master) nm -C src/.libs/libbitcoinconsensus.dylib | rg _bitcoinconsensus_ ➜ git:(master) ``` We do have a [second check](https://github.com/bitcoin/bitcoin/blob/f4de89edfa8be4501534fec0c662c650a4ce7ef2/configure.ac#L882) for the `visibility` attribute, which works for Darwin as it's only testing for default visibility, however the result of this check isn't used at all. It was added in #4725, along with the `--enable-reduce-exports` option, however when libbitcoinconsensus was added in #5235, it used the results of the added `AX_GCC_FUNC_ATTRIBUTE` calls. This PR removes our usage of the AX_GCC_FUNC_ATTRIBUTE macro entirely, in favour of our own checks in configure. This meant adding a check for `dllexport`, which I've tested as working with both [GCC](https://gcc.gnu.org/onlinedocs/gcc/Microsoft-Windows-Function-Attributes.html) and [Clang](https://releases.llvm.org/10.0.0/tools/clang/docs/AttributeReference.html#dllexport) when building for Windows. I haven't added an equivalent check for `dllimport`, as we weren't actually using the result of that check, we're just testing that `MSC_VER` was defined before using. With these changes building a libbitcoinconsensus with reduced exports, when targeting Darwin, works as expected: ```bash ./autogen.sh ./configure --disable-tests --disable-bench --with-utils=no --with-daemon=no --with-gui=no --disable-wallet --with-libs=yes --enable-reduce-exports make -j8 ... nm -C src/.libs/libbitcoinconsensus.dylib | rg _bitcoinconsensus_ 000000000000a340 T _bitcoinconsensus_verify_script 00000000000097e0 T _bitcoinconsensus_verify_script_with_amount 000000000000a3c0 T _bitcoinconsensus_version ``` ```python >>> import ctypes >>> consensus = ctypes.CDLL("src/.libs/libbitcoinconsensus.dylib") >>> print(consensus.bitcoinconsensus_version()) 1 >>> exit() ``` TODO: Modify a CI job to compile with --enable-reduce-exports and check for symbols in shared lib? ACKs for top commit: laanwj: Code review ACK de4238f92f4c067f099663f68d9772105de81d75 Tree-SHA512: d148f3c55d14dac6e9e5b718cc65bb557bcf6f663218d24bc9044b86281bd5dd3d931ebea79c336a58e8ed50d683218c0a9e75494f2267b91097665043e252ae --- build-aux/m4/ax_gcc_func_attribute.m4 | 223 -------------------------- configure.ac | 37 +++-- src/script/bitcoinconsensus.h | 12 +- 3 files changed, 26 insertions(+), 246 deletions(-) delete mode 100644 build-aux/m4/ax_gcc_func_attribute.m4 diff --git a/build-aux/m4/ax_gcc_func_attribute.m4 b/build-aux/m4/ax_gcc_func_attribute.m4 deleted file mode 100644 index c788ca9bd4..0000000000 --- a/build-aux/m4/ax_gcc_func_attribute.m4 +++ /dev/null @@ -1,223 +0,0 @@ -# =========================================================================== -# http://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html -# =========================================================================== -# -# SYNOPSIS -# -# AX_GCC_FUNC_ATTRIBUTE(ATTRIBUTE) -# -# DESCRIPTION -# -# This macro checks if the compiler supports one of GCC's function -# attributes; many other compilers also provide function attributes with -# the same syntax. Compiler warnings are used to detect supported -# attributes as unsupported ones are ignored by default so quieting -# warnings when using this macro will yield false positives. -# -# The ATTRIBUTE parameter holds the name of the attribute to be checked. -# -# If ATTRIBUTE is supported define HAVE_FUNC_ATTRIBUTE_. -# -# The macro caches its result in the ax_cv_have_func_attribute_ -# variable. -# -# The macro currently supports the following function attributes: -# -# alias -# aligned -# alloc_size -# always_inline -# artificial -# cold -# const -# constructor -# constructor_priority for constructor attribute with priority -# deprecated -# destructor -# dllexport -# dllimport -# error -# externally_visible -# flatten -# format -# format_arg -# gnu_inline -# hot -# ifunc -# leaf -# malloc -# noclone -# noinline -# nonnull -# noreturn -# nothrow -# optimize -# pure -# unused -# used -# visibility -# warning -# warn_unused_result -# weak -# weakref -# -# Unsuppored function attributes will be tested with a prototype returning -# an int and not accepting any arguments and the result of the check might -# be wrong or meaningless so use with care. -# -# LICENSE -# -# Copyright (c) 2013 Gabriele Svelto -# -# 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 3 - -AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [ - AS_VAR_PUSHDEF([ac_var], [ax_cv_have_func_attribute_$1]) - - AC_CACHE_CHECK([for __attribute__(($1))], [ac_var], [ - AC_LINK_IFELSE([AC_LANG_PROGRAM([ - m4_case([$1], - [alias], [ - int foo( void ) { return 0; } - int bar( void ) __attribute__(($1("foo"))); - ], - [aligned], [ - int foo( void ) __attribute__(($1(32))); - ], - [alloc_size], [ - void *foo(int a) __attribute__(($1(1))); - ], - [always_inline], [ - inline __attribute__(($1)) int foo( void ) { return 0; } - ], - [artificial], [ - inline __attribute__(($1)) int foo( void ) { return 0; } - ], - [cold], [ - int foo( void ) __attribute__(($1)); - ], - [const], [ - int foo( void ) __attribute__(($1)); - ], - [constructor_priority], [ - int foo( void ) __attribute__((__constructor__(65535/2))); - ], - [constructor], [ - int foo( void ) __attribute__(($1)); - ], - [deprecated], [ - int foo( void ) __attribute__(($1(""))); - ], - [destructor], [ - int foo( void ) __attribute__(($1)); - ], - [dllexport], [ - __attribute__(($1)) int foo( void ) { return 0; } - ], - [dllimport], [ - int foo( void ) __attribute__(($1)); - ], - [error], [ - int foo( void ) __attribute__(($1(""))); - ], - [externally_visible], [ - int foo( void ) __attribute__(($1)); - ], - [flatten], [ - int foo( void ) __attribute__(($1)); - ], - [format], [ - int foo(const char *p, ...) __attribute__(($1(printf, 1, 2))); - ], - [format_arg], [ - char *foo(const char *p) __attribute__(($1(1))); - ], - [gnu_inline], [ - inline __attribute__(($1)) int foo( void ) { return 0; } - ], - [hot], [ - int foo( void ) __attribute__(($1)); - ], - [ifunc], [ - int my_foo( void ) { return 0; } - static int (*resolve_foo(void))(void) { return my_foo; } - int foo( void ) __attribute__(($1("resolve_foo"))); - ], - [leaf], [ - __attribute__(($1)) int foo( void ) { return 0; } - ], - [malloc], [ - void *foo( void ) __attribute__(($1)); - ], - [noclone], [ - int foo( void ) __attribute__(($1)); - ], - [noinline], [ - __attribute__(($1)) int foo( void ) { return 0; } - ], - [nonnull], [ - int foo(char *p) __attribute__(($1(1))); - ], - [noreturn], [ - void foo( void ) __attribute__(($1)); - ], - [nothrow], [ - int foo( void ) __attribute__(($1)); - ], - [optimize], [ - __attribute__(($1(3))) int foo( void ) { return 0; } - ], - [pure], [ - int foo( void ) __attribute__(($1)); - ], - [unused], [ - int foo( void ) __attribute__(($1)); - ], - [used], [ - int foo( void ) __attribute__(($1)); - ], - [visibility], [ - int foo_def( void ) __attribute__(($1("default"))); - int foo_hid( void ) __attribute__(($1("hidden"))); - int foo_int( void ) __attribute__(($1("internal"))); - int foo_pro( void ) __attribute__(($1("protected"))); - ], - [warning], [ - int foo( void ) __attribute__(($1(""))); - ], - [warn_unused_result], [ - int foo( void ) __attribute__(($1)); - ], - [weak], [ - int foo( void ) __attribute__(($1)); - ], - [weakref], [ - static int foo( void ) { return 0; } - static int bar( void ) __attribute__(($1("foo"))); - ], - [ - m4_warn([syntax], [Unsupported attribute $1, the test may fail]) - int foo( void ) __attribute__(($1)); - ] - )], []) - ], - dnl GCC doesn't exit with an error if an unknown attribute is - dnl provided but only outputs a warning, so accept the attribute - dnl only if no warning were issued. - [AS_IF([test -s conftest.err], - [AS_VAR_SET([ac_var], [no])], - [AS_VAR_SET([ac_var], [yes])])], - [AS_VAR_SET([ac_var], [no])]) - ]) - - AS_IF([test yes = AS_VAR_GET([ac_var])], - [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_FUNC_ATTRIBUTE_$1), 1, - [Define to 1 if the system has the `$1' function attribute])], []) - - AS_VAR_POPDEF([ac_var]) -]) diff --git a/configure.ac b/configure.ac index e86fc71d9a..989cbbcfe9 100644 --- a/configure.ac +++ b/configure.ac @@ -913,10 +913,6 @@ if test x$ac_cv_sys_large_files != x && CPPFLAGS="$CPPFLAGS -D_LARGE_FILES=$ac_cv_sys_large_files" fi -AX_GCC_FUNC_ATTRIBUTE([visibility]) -AX_GCC_FUNC_ATTRIBUTE([dllexport]) -AX_GCC_FUNC_ATTRIBUTE([dllimport]) - AC_SEARCH_LIBS([clock_gettime],[rt]) if test "x$enable_gprof" = xyes; then @@ -1078,13 +1074,13 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ [ AC_MSG_RESULT(no)] ) -AC_MSG_CHECKING([for visibility attribute]) -AC_LINK_IFELSE([AC_LANG_SOURCE([ - int foo_def( void ) __attribute__((visibility("default"))); +AC_MSG_CHECKING([for default visibility attribute]) +AC_COMPILE_IFELSE([AC_LANG_SOURCE([ + int foo(void) __attribute__((visibility("default"))); int main(){} ])], [ - AC_DEFINE(HAVE_VISIBILITY_ATTRIBUTE,1,[Define if the visibility attribute is supported.]) + AC_DEFINE(HAVE_DEFAULT_VISIBILITY_ATTRIBUTE,1,[Define if the visibility attribute is supported.]) AC_MSG_RESULT(yes) ], [ @@ -1095,6 +1091,18 @@ AC_LINK_IFELSE([AC_LANG_SOURCE([ ] ) +AC_MSG_CHECKING([for dllexport attribute]) +AC_COMPILE_IFELSE([AC_LANG_SOURCE([ + __declspec(dllexport) int foo(void); + int main(){} + ])], + [ + AC_DEFINE(HAVE_DLLEXPORT_ATTRIBUTE,1,[Define if the dllexport attribute is supported.]) + AC_MSG_RESULT(yes) + ], + [AC_MSG_RESULT(no)] +) + if test "x$use_thread_local" = xyes || test "x$use_thread_local" = xauto; then TEMP_LDFLAGS="$LDFLAGS" LDFLAGS="$TEMP_LDFLAGS $PTHREAD_CFLAGS" @@ -1269,12 +1277,6 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ [ AC_MSG_RESULT(no); HAVE_STRONG_GETAUXVAL=0 ] ) -dnl Check for reduced exports -if test x$use_reduce_exports = xyes; then - AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],[RE_CXXFLAGS="-fvisibility=hidden"], - [AC_MSG_ERROR([Cannot set default symbol visibility. Use --disable-reduce-exports.])]) -fi - AC_MSG_CHECKING([for std::system]) AC_LINK_IFELSE( [ AC_LANG_PROGRAM( @@ -1486,9 +1488,11 @@ fi BOOST_LIBS="$BOOST_LDFLAGS $BOOST_SYSTEM_LIB $BOOST_FILESYSTEM_LIB" fi +dnl Check for reduced exports if test x$use_reduce_exports = xyes; then - CXXFLAGS="$CXXFLAGS $RE_CXXFLAGS" - AX_CHECK_LINK_FLAG([[-Wl,--exclude-libs,ALL]], [RELDFLAGS="-Wl,--exclude-libs,ALL"],, [[$LDFLAG_WERROR]]) + AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],[CXXFLAGS="$CXXFLAGS -fvisibility=hidden"], + [AC_MSG_ERROR([Cannot set hidden symbol visibility. Use --disable-reduce-exports.])],[[$CXXFLAG_WERROR]]) + AX_CHECK_LINK_FLAG([[-Wl,--exclude-libs,ALL]],[RELDFLAGS="-Wl,--exclude-libs,ALL"],,[[$LDFLAG_WERROR]]) fi if test x$use_tests = xyes; then @@ -1951,6 +1955,7 @@ echo echo "Options used to compile and link:" echo " boost process = $with_boost_process" echo " multiprocess = $build_multiprocess" +echo " with libs = $build_bitcoin_libs" echo " with wallet = $enable_wallet" echo " with gui / qt = $bitcoin_enable_qt" if test "x$enable_wallet" != "xno"; then diff --git a/src/script/bitcoinconsensus.h b/src/script/bitcoinconsensus.h index 63958ac377..5fa4ac3a52 100644 --- a/src/script/bitcoinconsensus.h +++ b/src/script/bitcoinconsensus.h @@ -11,14 +11,12 @@ #if defined(BUILD_BITCOIN_INTERNAL) && defined(HAVE_CONFIG_H) #include #if defined(_WIN32) - #if defined(DLL_EXPORT) - #if defined(HAVE_FUNC_ATTRIBUTE_DLLEXPORT) - #define EXPORT_SYMBOL __declspec(dllexport) - #else - #define EXPORT_SYMBOL - #endif + #if defined(HAVE_DLLEXPORT_ATTRIBUTE) + #define EXPORT_SYMBOL __declspec(dllexport) + #else + #define EXPORT_SYMBOL #endif - #elif defined(HAVE_FUNC_ATTRIBUTE_VISIBILITY) + #elif defined(HAVE_DEFAULT_VISIBILITY_ATTRIBUTE) #define EXPORT_SYMBOL __attribute__ ((visibility ("default"))) #endif #elif defined(MSC_VER) && !defined(STATIC_LIBBITCOINCONSENSUS)