Use LLVM libunwind for stack unwinding on Unix

This change replaces external libunwind usage on Unix by a copy of the LLVM libunwind.
It also modifies libunwind to support reporting register location and implements
the unw_get_save_loc API to get this location.
For now, only memory locations are supported (register locations are not).

Author: janvorli

THIRD-PARTY-NOTICES

@@ -0,0 +1,59 @@
+.NET Core uses third-party libraries or other resources that may be
+distributed under licenses different than the .NET Core software.
+
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+
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+The attached notices are provided for information only.
+
+License notice for The LLVM Compiler Infrastructure
+---------------------------------------------------
+==============================================================================
+LLVM Release License
+==============================================================================
+University of Illinois/NCSA
+Open Source License
+
+Copyright (c) 2003-2015 University of Illinois at Urbana-Champaign.
+All rights reserved.
+
+Developed by:
+
+    LLVM Team
+
+    University of Illinois at Urbana-Champaign
+
+    http://llvm.org
+
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+      this list of conditions and the following disclaimers.
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+      Urbana-Champaign, nor the names of its contributors may be used to
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+SOFTWARE.
+

src/Native/Runtime/CMakeLists.txt

@@ -93,6 +93,12 @@ else()
   include_directories(unix)
   include_directories(../libunwind/include)
 
+  # Disable building _Unwind_XXX style APIs of libunwind, since we don't use them.
+  add_definitions(-D_LIBUNWIND_DISABLE_ZERO_COST_APIS=1)
+
+  # Compile unwinding only for the current compilation target architecture
+  add_definitions(-D_LIBUNWIND_IS_NATIVE_ONLY)
+
   list(APPEND COMMON_RUNTIME_SOURCES
     unix/PalRedhawkUnix.cpp
   )
@@ -105,6 +111,12 @@ else()
     ../libunwind/src/libunwind.cpp
   )
 
+  if(CLR_CMAKE_PLATFORM_DARWIN)
+    list(APPEND FULL_RUNTIME_SOURCES
+      ../libunwind/src/Unwind_AppleExtras.cpp
+    )
+  endif()
+
   if(CLR_CMAKE_PLATFORM_ARCH_AMD64)
     set(ARCH_SOURCES_DIR amd64)
     set(ASM_SUFFIX S)
@@ -117,8 +129,8 @@ else()
   endif()
 
   list(APPEND RUNTIME_SOURCES_ARCH_ASM
-    ../libunwind/src/UnwindRegistersRestore.${ASM_SUFFIX}
-    ../libunwind/src/UnwindRegistersSave.${ASM_SUFFIX}
+    ../libunwind/src/UnwindRegistersRestore.S
+    ../libunwind/src/UnwindRegistersSave.S
   )
 endif()
 

src/Native/Runtime/startup.cpp

@@ -70,15 +70,13 @@ bool InitDLL(HANDLE hPalInstance)
     if (!RestrictedCallouts::Initialize())
         return false;
 
-#ifndef USE_PORTABLE_HELPERS
-#ifndef APP_LOCAL_RUNTIME
+#if !defined(APP_LOCAL_RUNTIME) && !defined(USE_PORTABLE_HELPERS)
 #ifndef PLATFORM_UNIX
     PalAddVectoredExceptionHandler(1, RhpVectoredExceptionHandler);
 #else
     PalSetHardwareExceptionHandler(RhpHardwareExceptionHandler);
 #endif
-#endif
-#endif
+#endif // !APP_LOCAL_RUNTIME && !USE_PORTABLE_HELPERS
 
     //
     // init per-instance state

src/Native/Runtime/unix/PalRedhawkUnix.cpp

@@ -443,12 +443,12 @@ REDHAWK_PALEXPORT bool REDHAWK_PALAPI PalInit()
     {
         return false;
     }
-#ifndef USE_PORTABLE_HELPERS 
+#ifndef USE_PORTABLE_HELPERS
     if (!InitializeHardwareExceptionHandling())
     {
         return false;
     }
-#endif
+#endif // !USE_PORTABLE_HELPERS
     int status = pthread_key_create(&g_threadKey, TlsObjectDestructor);
     if (status != 0)
     {

src/Native/Runtime/unix/UnixContext.cpp

@@ -11,10 +11,6 @@
 #include "regdisplay.h"
 #include "config.h"
 
-#if !HAVE_LIBUNWIND_H
-#error Don't know how to unwind on this platform
-#endif
-
 #include <libunwind.h>
 
 #if HAVE_UCONTEXT_T

src/Native/Runtime/unix/config.h.in

@@ -4,7 +4,6 @@
 #cmakedefine01 HAVE_SYS_VMPARAM_H
 #cmakedefine01 HAVE_MACH_VM_TYPES_H
 #cmakedefine01 HAVE_MACH_VM_PARAM_H
-#cmakedefine01 HAVE_LIBUNWIND_H
 
 #cmakedefine01 HAVE_PTHREAD_ATTR_GET_NP
 #cmakedefine01 HAVE_PTHREAD_GETATTR_NP

src/Native/Runtime/unix/configure.cmake

@@ -18,7 +18,6 @@ list(APPEND CMAKE_REQUIRED_DEFINITIONS -D_FILE_OFFSET_BITS=64)
 check_include_files(sys/vmparam.h HAVE_SYS_VMPARAM_H)
 check_include_files(mach/vm_types.h HAVE_MACH_VM_TYPES_H)
 check_include_files(mach/vm_param.h HAVE_MACH_VM_PARAM_H)
-check_include_files(libunwind.h HAVE_LIBUNWIND_H)
 
 check_library_exists(pthread pthread_attr_get_np "" HAVE_PTHREAD_ATTR_GET_NP)
 check_library_exists(pthread pthread_getattr_np "" HAVE_PTHREAD_GETATTR_NP)
@@ -106,9 +105,4 @@ int main()
   exit(ret);
 }" HAVE_MACH_ABSOLUTE_TIME)
 
-if(NOT HAVE_LIBUNWIND_H)
-  unset(HAVE_LIBUNWIND_H CACHE)
-  message(FATAL_ERROR "Cannot find libunwind. Try installing libunwind8 and libunwind8-dev (or the appropriate packages for your platform)")
-endif()
-
 configure_file(${CMAKE_CURRENT_LIST_DIR}/config.h.in ${CMAKE_CURRENT_BINARY_DIR}/config.h)

src/Native/libunwind/include/__libunwind_config.h

@@ -25,8 +25,8 @@
 #  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 9
 # elif defined(__x86_64__)
 #  define _LIBUNWIND_TARGET_X86_64 1
-#  define _LIBUNWIND_CONTEXT_SIZE 21
-#  define _LIBUNWIND_CURSOR_SIZE 33
+#  define _LIBUNWIND_CONTEXT_SIZE 42
+#  define _LIBUNWIND_CURSOR_SIZE 54
 #  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 17
 # elif defined(__ppc__)
 #  define _LIBUNWIND_TARGET_PPC 1

src/Native/libunwind/include/libunwind.h

@@ -95,6 +95,26 @@ struct unw_proc_info_t {
 };
 typedef struct unw_proc_info_t unw_proc_info_t;
 
+enum unw_save_loc_type_t
+{
+    UNW_SLT_NONE,       /* register is not saved ("not an l-value") */
+    UNW_SLT_MEMORY,     /* register has been saved in memory */
+    UNW_SLT_REG         /* register has been saved in (another) register */
+};
+typedef enum unw_save_loc_type_t unw_save_loc_type_t;
+
+struct unw_save_loc_t
+{
+    unw_save_loc_type_t type;
+    union
+    {
+        unw_word_t addr;        /* valid if type==UNW_SLT_MEMORY */
+        unw_regnum_t regnum;    /* valid if type==UNW_SLT_REG */
+    }
+    u;
+};
+typedef struct unw_save_loc_t unw_save_loc_t;
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -119,7 +139,7 @@ extern int unw_get_proc_info(unw_cursor_t *, unw_proc_info_t *) LIBUNWIND_AVAIL;
 extern int unw_is_fpreg(unw_cursor_t *, unw_regnum_t) LIBUNWIND_AVAIL;
 extern int unw_is_signal_frame(unw_cursor_t *) LIBUNWIND_AVAIL;
 extern int unw_get_proc_name(unw_cursor_t *, char *, size_t, unw_word_t *) LIBUNWIND_AVAIL;
-//extern int       unw_get_save_loc(unw_cursor_t*, int, unw_save_loc_t*);
+extern int unw_get_save_loc(unw_cursor_t*, int, unw_save_loc_t*);
 
 extern unw_addr_space_t unw_local_addr_space;