2 files changed, 66 insertions, 0 deletions
diff --git a/lib/builtins/gcc_personality_v0.c b/lib/builtins/gcc_personality_v0.c
index 29e5be30712f..0bc765624564 100644
@@ -12,6 +12,17 @@
+#if defined(__arm__) && !defined(__ARM_DWARF_EH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+ * When building with older compilers (e.g. clang <3.9), it is possible that we
+ * have a version of unwind.h which does not provide the EHABI declarations
+ * which are quired for the C personality to conform to the specification. In
+ * order to provide forward compatibility for such compilers, we re-declare the
+ * necessary interfaces in the helper to permit a standalone compilation of the
+ * builtins (which contains the C unwinding personality for historical reasons).
* Pointer encodings documented at:
diff --git a/lib/builtins/unwind-ehabi-helpers.h b/lib/builtins/unwind-ehabi-helpers.h
new file mode 100644
@@ -0,0 +1,55 @@
+/* ===-- arm-ehabi-helpers.h - Supplementary ARM EHABI declarations --------===
+ * The LLVM Compiler Infrastructure
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ * ===--------------------------------------------------------------------=== */
+/* NOTE: see reasoning for this inclusion below */
+ * NOTE: _URC_OK, _URC_FAILURE must be present as preprocessor tokens. This
+ * allows for a substitution of a constant which can be cast into the
+ * appropriate enumerated type. This header is expected to always be included
+ * AFTER unwind.h (which is why it is forcefully included above). This ensures
+ * that we do not overwrite the token for the enumeration. Subsequent uses of
+ * the token would be clean to rewrite with constant values.
+ * The typedef redeclaration should be safe. Due to the protection granted to
+ * us by the `__ARM_EABI_UNWINDER__` above, we are guaranteed that we are in a
+ * header not vended by gcc. The HP unwinder (being an itanium unwinder) does
+ * not support EHABI, and the GNU unwinder, derived from the HP unwinder, also
+ * does not support EHABI as of the introduction of this header. As such, we
+ * are fairly certain that we are in the LLVM case. Here, _Unwind_State is a
+ * typedef, and so we can get away with a redeclaration.
+ * Guarded redefinitions of the needed unwind state prevent the redefinition of
+ * those states.
+#define _URC_OK 0
+#define _URC_FAILURE 9
+typedef uint32_t _Unwind_State;
+#define _US_UNWIND_FRAME_STARTING ((_Unwind_State)1)
+#define _US_ACTION_MASK ((_Unwind_State)3)