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| author | Christian Pfeiffer <cpfeiffer@live.de> | 2017-11-07 16:02:47 +0100 |
|---|---|---|
| committer | Brad King <brad.king@kitware.com> | 2017-11-08 08:10:52 -0500 |
| commit | 41aacca7fb61eccf673024180e6020250fb301b2 (patch) | |
| tree | 6da56ac28dc8f6f6d86a59ea04de2f17ae47d9db /Modules/CMakeParseImplicitLinkInfo.cmake | |
| parent | ddeabf05d80db0758708ec502a68def11b4f9591 (diff) | |
| download | cmake-41aacca7fb61eccf673024180e6020250fb301b2.tar.gz | |
Restore exclusion of "gcc_eh" from implicit link libraries
Since commit v3.9.0-rc1~148^2 (Do not assume GCC libs are linked by all
compilers, 2017-05-05) we no longer filter out all `gcc*` implicit link
libraries. This allows mixing of gcc and non-gcc compilers across
languages. However, this caused a subtle problem with how GCC makes
exception handling symbols available to linked binaries.
GCC (at least on MinGW) provides two different libraries with exception
handling symbols:
* gcc_s: A shared library with -fvisibility=default, used by -shared-libgcc.
* gcc_eh: A static library with -fvisibility=hidden, used by -static-libgcc.
The C compiler (on MinGW) defaults to -static-libgcc and uses gcc_eh.
The C++ compiler defaults to -shared-libgcc and uses gcc_s when linking
shared libraries and executables so that exceptions can propagate across
shared libraries [1]. When linking a mixed-language binary, the C++
compiler should be used along with its choice of gcc_s. In this case
gcc_eh should not be added even though the C compiler implies it because
gcc_s supersedes it.
Since the above-mentioned change, CMake is adding gcc_eh to C++ link
lines that also contain C code on MinGW. This causes both gcc_s and
gcc_eh to be used, which is incorrect. We can fix this simply by
excluding gcc_eh from the C compiler's implicit link libraries.
[1] https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/Link-Options.html#Link-Options
Fixes: #17436
Diffstat (limited to 'Modules/CMakeParseImplicitLinkInfo.cmake')
| -rw-r--r-- | Modules/CMakeParseImplicitLinkInfo.cmake | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Modules/CMakeParseImplicitLinkInfo.cmake b/Modules/CMakeParseImplicitLinkInfo.cmake index 3b772784b4..63d18abec1 100644 --- a/Modules/CMakeParseImplicitLinkInfo.cmake +++ b/Modules/CMakeParseImplicitLinkInfo.cmake @@ -142,7 +142,7 @@ function(CMAKE_PARSE_IMPLICIT_LINK_INFO text lib_var dir_var fwk_var log_var obj # We remove items that are not language-specific. set(implicit_libs "") foreach(lib IN LISTS implicit_libs_tmp) - if("x${lib}" MATCHES "^x(crt.*\\.o|System.*|.*libclang_rt.*|msvcrt.*|libvcruntime.*|libucrt.*|libcmt.*)$") + if("x${lib}" MATCHES "^x(crt.*\\.o|gcc_eh.*|System.*|.*libclang_rt.*|msvcrt.*|libvcruntime.*|libucrt.*|libcmt.*)$") string(APPEND log " remove lib [${lib}]\n") elseif(IS_ABSOLUTE "${lib}") get_filename_component(abs "${lib}" ABSOLUTE) |