Merge pull request #3045 from benpye/allow-llvm-unwind

Detect libunwind features allowing LLVMs libunwind to be used

Author: jkotas

src/pal/src/CMakeLists.txt

@@ -228,26 +228,38 @@ endif(CMAKE_SYSTEM_NAME STREQUAL FreeBSD)
 
 if(CMAKE_SYSTEM_NAME STREQUAL Linux)
   if(PAL_CMAKE_PLATFORM_ARCH_ARM)
-    target_link_libraries(coreclrpal
-      unwind-arm
-    )
+    find_library(UNWIND_ARCH NAMES unwind-arm)
   endif()
 
   if(PAL_CMAKE_PLATFORM_ARCH_AMD64)
-    target_link_libraries(coreclrpal
-      unwind-x86_64
-    )
+    find_library(UNWIND_ARCH NAMES unwind-x86_64)
   endif()
 
+  find_library(UNWIND NAMES unwind)
+  find_library(UNWIND_GENERIC NAMES unwind-generic)
+
   target_link_libraries(coreclrpal
     gcc_s
     pthread
     rt
     dl
-    unwind
-    unwind-generic
     uuid
   )
+
+  if(UNWIND STREQUAL UNWIND-NOTFOUND)
+    message(FATAL_ERROR "Cannot find libunwind. Try installing libunwind8-dev and libunwind8.")
+  endif(UNWIND STREQUAL UNWIND-NOTFOUND)
+
+  target_link_libraries(coreclrpal ${UNWIND})
+
+  if(NOT UNWIND_GENERIC STREQUAL UNWIND_GENERIC-NOTFOUND)
+    target_link_libraries(coreclrpal ${UNWIND_GENERIC})
+  endif(NOT UNWIND_GENERIC STREQUAL UNWIND_GENERIC-NOTFOUND)
+
+  if(NOT UNWIND_ARCH STREQUAL UNWIND_ARCH-NOTFOUND)
+    target_link_libraries(coreclrpal ${UNWIND_ARCH})
+  endif(NOT UNWIND_ARCH STREQUAL UNWIND_ARCH-NOTFOUND)
+
 endif(CMAKE_SYSTEM_NAME STREQUAL Linux)
 
 if(CMAKE_SYSTEM_NAME STREQUAL NetBSD)

src/pal/src/configure.cmake

@@ -75,6 +75,8 @@ check_function_exists(directio HAVE_DIRECTIO)
 check_function_exists(semget HAS_SYSV_SEMAPHORES)
 check_function_exists(pthread_mutex_init HAS_PTHREAD_MUTEXES)
 check_function_exists(ttrace HAVE_TTRACE)
+check_function_exists(unw_get_save_loc HAVE_UNW_GET_SAVE_LOC)
+check_function_exists(unw_get_accessors HAVE_UNW_GET_ACCESSORS)
 
 check_struct_has_member ("struct stat" st_atimespec "sys/types.h;sys/stat.h" HAVE_STAT_TIMESPEC)
 check_struct_has_member ("struct stat" st_atimensec "sys/types.h;sys/stat.h" HAVE_STAT_NSEC)

src/pal/src/exception/seh-unwind.cpp

@@ -157,10 +157,7 @@ static void UnwindContextToWinContext(unw_cursor_t *cursor, CONTEXT *winContext)
 
 static void GetContextPointer(unw_cursor_t *cursor, unw_context_t *unwContext, int reg, SIZE_T **contextPointer)
 {
-#if defined(__APPLE__)
-    // Returning NULL indicates that we don't have context pointers available
-    *contextPointer = NULL;
-#else
+#if defined(HAVE_UNW_GET_SAVE_LOC)
     unw_save_loc_t saveLoc;
     unw_get_save_loc(cursor, reg, &saveLoc);
     if (saveLoc.type == UNW_SLT_MEMORY)
@@ -170,6 +167,9 @@ static void GetContextPointer(unw_cursor_t *cursor, unw_context_t *unwContext, i
         if (unwContext == NULL || (pLoc < (SIZE_T *)unwContext) || ((SIZE_T *)(unwContext + 1) <= pLoc))
             *contextPointer = (SIZE_T *)saveLoc.u.addr;
     }
+#else
+    // Returning NULL indicates that we don't have context pointers available
+    *contextPointer = NULL;
 #endif
 }
 
@@ -302,7 +302,7 @@ BOOL PAL_VirtualUnwind(CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *contextP
 
 // These methods are only used on the AMD64 build
 #ifdef _AMD64_
-#ifdef __LINUX__
+#ifdef HAVE_UNW_GET_ACCESSORS
 
 static struct LibunwindCallbacksInfoType
 {
@@ -528,7 +528,7 @@ BOOL PAL_VirtualUnwindOutOfProc(CONTEXT *context,
     }    
     return result;
 }
-#else // __LINUX__
+#else // HAVE_UNW_GET_ACCESSORS
 
 BOOL PAL_VirtualUnwindOutOfProc(CONTEXT *context, 
                                 KNONVOLATILE_CONTEXT_POINTERS *contextPointers, 
@@ -539,7 +539,7 @@ BOOL PAL_VirtualUnwindOutOfProc(CONTEXT *context,
     return FALSE;
 }
 
-#endif // !__LINUX__
+#endif // !HAVE_UNW_GET_ACCESSORS
 #endif // _AMD64_
 
 /*++