[libunwind] 57fc8ec - Reland "Enable `-funwind-tables` flag when building libunwind"
Sergej Jaskiewicz via cfe-commits
cfe-commits at lists.llvm.org
Tue Dec 10 17:27:22 PST 2019
Author: Sergej Jaskiewicz
Date: 2019-12-11T04:27:04+03:00
New Revision: 57fc8ecdbaa7fbb1a13907ca3f7a3cb9f9459d27
URL: https://github.com/llvm/llvm-project/commit/57fc8ecdbaa7fbb1a13907ca3f7a3cb9f9459d27
DIFF: https://github.com/llvm/llvm-project/commit/57fc8ecdbaa7fbb1a13907ca3f7a3cb9f9459d27.diff
LOG: Reland "Enable `-funwind-tables` flag when building libunwind"
Summary:
Relands https://reviews.llvm.org/D70815.
The original commit set `CMAKE_TRY_COMPILE_TARGET_TYPE` to
`STATIC_LIBRARY` globally in libunwind/CMakeLists.txt, which effectively
disabled the linking step in CMake checks.
This broke some builds (see 938c70b86c7d2165f8c28d5700e9c1ac1263307e).
Here we set CMAKE_TRY_COMPILE_TARGET_TYPE to
STATIC_LIBRARY only when checking for presence of the `-funwind-tables`
flag, and then set it back to the original value so it doesn't affect
other checks.
Reviewers: mstorsjo, jfb
Subscribers: mgorny, christof, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D71117
Added:
Modified:
libunwind/CMakeLists.txt
libunwind/cmake/config-ix.cmake
libunwind/test/CMakeLists.txt
libunwind/test/libunwind/test/config.py
libunwind/test/lit.site.cfg.in
libunwind/test/signal_frame.pass.cpp
Removed:
################################################################################
diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
index 08095d1333a5..6dd0a15405b5 100644
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -291,7 +291,29 @@ endif()
add_cxx_compile_flags_if_supported(-fstrict-aliasing)
add_cxx_compile_flags_if_supported(-EHsc)
+# Don't run the linker in this CMake check.
+#
+# The reason why this was added is that when building libunwind for
+# ARM Linux, we need to pass the -funwind-tables flag in order for it to
+# work properly with ARM EHABI.
+#
+# However, when performing CMake checks, adding this flag causes the check
+# to produce a false negative, because the compiler generates calls
+# to __aeabi_unwind_cpp_pr0, which is defined in libunwind itself,
+# which isn't built yet, so the linker complains about undefined symbols.
+#
+# This leads to libunwind not being built with this flag, which makes
+# libunwind quite useless in this setup.
+set(_previous_CMAKE_TRY_COMPILE_TARGET_TYPE ${CMAKE_TRY_COMPILE_TARGET_TYPE})
+set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
add_compile_flags_if_supported(-funwind-tables)
+set(CMAKE_TRY_COMPILE_TARGET_TYPE ${_previous_CMAKE_TRY_COMPILE_TARGET_TYPE})
+
+if (LIBUNWIND_USES_ARM_EHABI AND NOT LIBUNWIND_SUPPORTS_FUNWIND_TABLES_FLAG)
+ message(SEND_ERROR "The -funwind-tables flag must be supported "
+ "because this target uses ARM Exception Handling ABI")
+endif()
+
add_cxx_compile_flags_if_supported(-fno-exceptions)
add_cxx_compile_flags_if_supported(-fno-rtti)
diff --git a/libunwind/cmake/config-ix.cmake b/libunwind/cmake/config-ix.cmake
index 02d2f13f2e28..0d833e996ca1 100644
--- a/libunwind/cmake/config-ix.cmake
+++ b/libunwind/cmake/config-ix.cmake
@@ -2,6 +2,7 @@ include(CMakePushCheckState)
include(CheckCCompilerFlag)
include(CheckCXXCompilerFlag)
include(CheckLibraryExists)
+include(CheckSymbolExists)
include(CheckCSourceCompiles)
check_library_exists(c fopen "" LIBUNWIND_HAS_C_LIB)
@@ -73,3 +74,13 @@ check_cxx_compiler_flag(-nostdinc++ LIBUNWIND_HAS_NOSTDINCXX_FLAG)
# Check libraries
check_library_exists(dl dladdr "" LIBUNWIND_HAS_DL_LIB)
check_library_exists(pthread pthread_once "" LIBUNWIND_HAS_PTHREAD_LIB)
+
+# Check symbols
+check_symbol_exists(__arm__ "" LIBUNWIND_TARGET_ARM)
+check_symbol_exists(__USING_SJLJ_EXCEPTIONS__ "" LIBUNWIND_USES_SJLJ_EXCEPTIONS)
+check_symbol_exists(__ARM_DWARF_EH__ "" LIBUNWIND_USES_DWARF_EH)
+
+if(LIBUNWIND_TARGET_ARM AND NOT LIBUNWIND_USES_SJLJ_EXCEPTIONS AND NOT LIBUNWIND_USES_DWARF_EH)
+ # This condition is copied from __libunwind_config.h
+ set(LIBUNWIND_USES_ARM_EHABI ON)
+endif()
diff --git a/libunwind/test/CMakeLists.txt b/libunwind/test/CMakeLists.txt
index d902e3e82941..40d4acd4e8c2 100644
--- a/libunwind/test/CMakeLists.txt
+++ b/libunwind/test/CMakeLists.txt
@@ -16,6 +16,7 @@ pythonize_bool(LIBCXX_ENABLE_SHARED)
pythonize_bool(LIBUNWIND_ENABLE_SHARED)
pythonize_bool(LIBUNWIND_ENABLE_THREADS)
pythonize_bool(LIBUNWIND_ENABLE_EXCEPTIONS)
+pythonize_bool(LIBUNWIND_USES_ARM_EHABI)
pythonize_bool(LIBUNWIND_USE_COMPILER_RT)
pythonize_bool(LIBUNWIND_BUILD_EXTERNAL_THREAD_LIBRARY)
set(LIBUNWIND_TARGET_INFO "libcxx.test.target_info.LocalTI" CACHE STRING
diff --git a/libunwind/test/libunwind/test/config.py b/libunwind/test/libunwind/test/config.py
index 05e3f3cc21f3..41ca3f9b4a44 100644
--- a/libunwind/test/libunwind/test/config.py
+++ b/libunwind/test/libunwind/test/config.py
@@ -37,6 +37,8 @@ def configure_features(self):
super(Configuration, self).configure_features()
if not self.get_lit_bool('enable_exceptions', True):
self.config.available_features.add('libcxxabi-no-exceptions')
+ if self.get_lit_bool('arm_ehabi', False):
+ self.config.available_features.add('libunwind-arm-ehabi')
def configure_compile_flags(self):
self.cxx.compile_flags += ['-DLIBUNWIND_NO_TIMER']
@@ -66,3 +68,11 @@ def configure_compile_flags_exceptions(self):
def configure_compile_flags_rtti(self):
pass
+
+ def configure_link_flags_cxx_library(self):
+ # libunwind tests should not link with libc++
+ pass
+
+ def configure_link_flags_abi_library(self):
+ # libunwind tests should not link with libc++abi
+ pass
diff --git a/libunwind/test/lit.site.cfg.in b/libunwind/test/lit.site.cfg.in
index 34da72ac1068..37f90a90efdb 100644
--- a/libunwind/test/lit.site.cfg.in
+++ b/libunwind/test/lit.site.cfg.in
@@ -19,6 +19,7 @@ config.executor = "@LIBUNWIND_EXECUTOR@"
config.libunwind_shared = @LIBUNWIND_ENABLE_SHARED@
config.enable_shared = @LIBCXX_ENABLE_SHARED@
config.enable_exceptions = @LIBUNWIND_ENABLE_EXCEPTIONS@
+config.arm_ehabi = @LIBUNWIND_USES_ARM_EHABI@
config.host_triple = "@LLVM_HOST_TRIPLE@"
config.target_triple = "@TARGET_TRIPLE@"
config.use_target = bool("@LIBUNWIND_TARGET_TRIPLE@")
diff --git a/libunwind/test/signal_frame.pass.cpp b/libunwind/test/signal_frame.pass.cpp
index a6f3f483bea5..a899461fafb4 100644
--- a/libunwind/test/signal_frame.pass.cpp
+++ b/libunwind/test/signal_frame.pass.cpp
@@ -9,6 +9,8 @@
// Ensure that functions marked as signal frames are reported as such.
+// UNSUPPORTED: libunwind-arm-ehabi
+
#include <assert.h>
#include <stdlib.h>
#include <libunwind.h>
@@ -20,9 +22,7 @@ void test() {
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
assert(unw_step(&cursor) > 0);
-#if !defined(_LIBUNWIND_ARM_EHABI)
assert(unw_is_signal_frame(&cursor));
-#endif
}
int main() {
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