[libunwind] Add a _LIBUNWIND_VERSION macro
This allows us to detect whether we're being compiled with LLVM's libunwind
more easily, without CMake having to set explicit variables.
As discussed in https://llvm.org/D119538.
Differential Revision: https://reviews.llvm.org/D121015
GitOrigin-RevId: f29002a4b71b7734dfc4bd0e62eec2d341edb3fd
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bf9f112..a7d6d19 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -485,11 +485,6 @@
add_definitions(-D_CRT_SECURE_NO_WARNINGS)
endif()
-# Define LIBCXXABI_USE_LLVM_UNWINDER for conditional compilation.
-if (LIBCXXABI_USE_LLVM_UNWINDER)
- add_definitions(-DLIBCXXABI_USE_LLVM_UNWINDER)
-endif()
-
if (LIBCXXABI_SILENT_TERMINATE)
add_definitions(-DLIBCXXABI_SILENT_TERMINATE)
endif()
diff --git a/src/cxa_personality.cpp b/src/cxa_personality.cpp
index f6e135f..b7ff4c2 100644
--- a/src/cxa_personality.cpp
+++ b/src/cxa_personality.cpp
@@ -22,6 +22,15 @@
#include "private_typeinfo.h"
#include "unwind.h"
+// TODO: This is a temporary workaround for libc++abi to recognize that it's being
+// built against LLVM's libunwind. LLVM's libunwind started reporting _LIBUNWIND_VERSION
+// in LLVM 15 -- we can remove this workaround after shipping LLVM 17. Once we remove
+// this workaround, it won't be possible to build libc++abi against libunwind headers
+// from LLVM 14 and before anymore.
+#if defined(____LIBUNWIND_CONFIG_H__) && !defined(_LIBUNWIND_VERSION)
+# define _LIBUNWIND_VERSION
+#endif
+
#if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
#include <windows.h>
#include <winnt.h>
@@ -1015,7 +1024,7 @@
}
// ARM register names
-#if !defined(LIBCXXABI_USE_LLVM_UNWINDER)
+#if !defined(_LIBUNWIND_VERSION)
static const uint32_t REG_UCB = 12; // Register to save _Unwind_Control_Block
#endif
static const uint32_t REG_SP = 13;
@@ -1050,7 +1059,7 @@
bool native_exception = __isOurExceptionClass(unwind_exception);
-#if !defined(LIBCXXABI_USE_LLVM_UNWINDER)
+#if !defined(_LIBUNWIND_VERSION)
// Copy the address of _Unwind_Control_Block to r12 so that
// _Unwind_GetLanguageSpecificData() and _Unwind_GetRegionStart() can
// return correct address.
