Allow disabling libunwind for backtrace (stability, default disabled for arm32/armhf else enabled), use cmake variable USE_LIBUNWIND

4 files changed, 39 insertions, 5 deletions

diff --git a/JaulibSetup.cmake b/JaulibSetup.cmake
index 477ce46..19b6541 100644
--- a/JaulibSetup.cmake
+++ b/JaulibSetup.cmake
@@ -125,6 +125,26 @@ message (STATUS "OS_NAME ${OS_NAME}")
 message (STATUS "OS_ARCH ${OS_ARCH} (${CMAKE_SYSTEM_PROCESSOR})")
 message (STATUS "OS_AND_ARCH ${OS_AND_ARCH}")
 
+message(STATUS "${PROJECT_NAME} USE_LIBUNWIND = ${USE_LIBUNWIND} (pre-set)")
+if(NOT DEFINED USE_LIBUNWIND)
+    if(${OS_ARCH} STREQUAL "armhf")
+        set(USE_LIBUNWIND OFF)
+        message(STATUS "${PROJECT_NAME} USE_LIBUNWIND ${USE_LIBUNWIND} (default armhf)")
+    else()
+        set(USE_LIBUNWIND ON)
+        message(STATUS "${PROJECT_NAME} USE_LIBUNWIND ${USE_LIBUNWIND} (default !armhf)")
+    endif()
+else()
+    message(STATUS "${PROJECT_NAME} USE_LIBUNWIND ${USE_LIBUNWIND} (user)")
+endif()
+if(USE_LIBUNWIND)
+    set(LIBUNWIND_LIBNAME "unwind")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DUSE_LIBUNWIND=1")
+else()
+    set(LIBUNWIND_LIBNAME "")
+endif()
+message(STATUS "${PROJECT_NAME} USE_LIBUNWIND ${USE_LIBUNWIND} -> libname ${LIBUNWIND_LIBNAME}")
+
 # Make a version file containing the current version from git.
 include (GetGitRevisionDescription)
 
diff --git a/README.md b/README.md
index 18b2fec..08eedcc 100644
--- a/README.md
+++ b/README.md
@@ -77,6 +77,11 @@ Disable stripping native lib even in non debug build:
 ~~~~~~~~~~~~~
 -DUSE_STRIP=OFF
 ~~~~~~~~~~~~~
+Disable using `libunwind` (default: enabled for all but `arm32`, `armhf`)
+~~~~~~~~~~~~~
+-DUSE_LIBUNWIND=OFF
+~~~~~~~~~~~~~
+
 Override default javac debug arguments `source,lines`:
 ~~~~~~~~~~~~~
 -DJAVAC_DEBUG_ARGS="source,lines,vars"
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index dcb2c60..6253666 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -21,7 +21,7 @@ set (jaulib_LIB_SRCS
 add_library (jaulib SHARED ${jaulib_LIB_SRCS})
 target_link_libraries (
   jaulib
-  unwind
+  ${LIBUNWIND_LIBNAME}
   ${CMAKE_THREAD_LIBS_INIT}
 )
 
diff --git a/src/debug.cpp b/src/debug.cpp
index acc77a7..08ae750 100644
--- a/src/debug.cpp
+++ b/src/debug.cpp
@@ -27,9 +27,11 @@
 
 #include <cstdarg>
 
-#define UNW_LOCAL_ONLY
-#include <libunwind.h>
-#include <cxxabi.h>
+#ifdef USE_LIBUNWIND
+    #define UNW_LOCAL_ONLY
+    #include <libunwind.h>
+    #include <cxxabi.h>
+#endif /* USE_LIBUNWIND */
 
 using namespace jau;
 
@@ -44,11 +46,12 @@ using namespace jau;
 #endif
 
 std::string jau::get_backtrace(const bool skip_anon_frames, const jau::snsize_t max_frames, const jau::snsize_t skip_frames) noexcept {
+    std::string out;
+#ifdef USE_LIBUNWIND
     // symbol:
     //  1: _ZN9direct_bt10DBTAdapter14startDiscoveryEbNS_19HCILEOwnAddressTypeEtt + 0x58d @ ip 0x7faa959d6daf, sp 0x7ffe38f301e0
     // de-mangled:
     //  1: direct_bt::DBTAdapter::startDiscovery(bool, direct_bt::HCILEOwnAddressType, unsigned short, unsigned short) + 0x58d @ ip 0x7f687b459071, sp 0x7fff2bf795d0
-    std::string out;
     jau::snsize_t frame=0;
     int res;
     char cstr[256];
@@ -108,6 +111,12 @@ std::string jau::get_backtrace(const bool skip_anon_frames, const jau::snsize_t
             out.append(line);
         }
     }
+#else /* USE_LIBUNWIND */
+    (void)skip_anon_frames;
+    (void)max_frames;
+    (void)skip_frames;
+    out.append("0: backtrace disabled\n");
+#endif /* USE_LIBUNWIND */
     return out;
 }