MFC r268993, r268893, r268994, plus partial r264070, r264082

 Fix C++ exception handling for ARM EABI.

 Just the part of r264070 that creates the FBSD_1.4 namespace in libc
 is hand-applied, and then r264082 which creates the Versions.def entry
 is MFC'd.

3 files changed, 111 insertions, 1 deletions

diff --git a/lib/libc/arm/Symbol.map b/lib/libc/arm/Symbol.map
index a58d443..cf65492 100644
--- a/lib/libc/arm/Symbol.map
+++ b/lib/libc/arm/Symbol.map
@@ -37,6 +37,11 @@ FBSD_1.3 {
 	__flt_rounds;
 };
 
+FBSD_1.4 {
+	__gnu_Unwind_Find_exidx;
+	dl_unwind_find_exidx;
+};
+
 FBSDprivate_1.0 {
 	/* PSEUDO syscalls */
 	__sys_getlogin;
diff --git a/lib/libc/arm/aeabi/Makefile.inc b/lib/libc/arm/aeabi/Makefile.inc
index a42831d..b9fd3c0 100644
--- a/lib/libc/arm/aeabi/Makefile.inc
+++ b/lib/libc/arm/aeabi/Makefile.inc
@@ -5,7 +5,8 @@
 SRCS+=	aeabi_atexit.c		\
 	aeabi_double.c		\
 	aeabi_float.c		\
-	aeabi_unwind_cpp.c
+	aeabi_unwind_cpp.c	\
+	aeabi_unwind_exidx.c
 .if ${MACHINE_ARCH:Marmv6*}
 SRCS+=	aeabi_vfp_double.S	\
 	aeabi_vfp_float.S
diff --git a/lib/libc/arm/aeabi/aeabi_unwind_exidx.c b/lib/libc/arm/aeabi/aeabi_unwind_exidx.c
new file mode 100644
index 0000000..d5af8b3
--- /dev/null
+++ b/lib/libc/arm/aeabi/aeabi_unwind_exidx.c
@@ -0,0 +1,104 @@
+/*-
+ * Copyright (c) 2014 Ian Lepore <ian@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <machine/elf.h>
+#include <link.h>
+#include <stddef.h>
+
+/*
+ * ARM EABI unwind helper.
+ *
+ * This finds the exidx section address and size associated with a given code
+ * address.  There are separate implementations for static and dynamic code.
+ *
+ * GCC expects this function to exist as __gnu_Unwind_Find_exidx(), clang and
+ * BSD tools expect it to be dl_unwind_find_exidx().  Both have the same API, so
+ * we set up an alias for GCC.
+ */
+__strong_reference(dl_unwind_find_exidx, __gnu_Unwind_Find_exidx);
+
+/*
+ * Each entry in the exidx section is a pair of 32-bit words.  We don't
+ * interpret the contents of the entries here; this typedef is just a local
+ * convenience for using sizeof() and doing pointer math.
+ */
+typedef struct exidx_entry {
+	uint32_t data[2];
+} exidx_entry;
+
+#ifdef __PIC__
+
+/*
+ * Unwind helper for dynamically linked code.
+ *
+ * This finds the shared object that contains the given address, and returns the
+ * address of the exidx section in that shared object along with the number of
+ * entries in that section, or NULL if it wasn't found.
+ */
+void *
+dl_unwind_find_exidx(const void *pc, int *pcount)
+{
+	const Elf_Phdr *hdr;
+	struct dl_phdr_info info;
+	int i;
+
+	if (_rtld_addr_phdr(pc, &info)) {
+		hdr = info.dlpi_phdr;
+		for (i = 0; i < info.dlpi_phnum; i++, hdr++) {
+			if (hdr->p_type == PT_ARM_EXIDX) {
+				*pcount = hdr->p_memsz / sizeof(exidx_entry);
+				return ((void *)(info.dlpi_addr + hdr->p_vaddr));
+			}
+		}
+	}
+	return (NULL);
+}
+
+#else	/* !__PIC__ */
+
+/*
+ * Unwind helper for statically linked code.
+ *
+ * In a statically linked program, the linker populates a pair of symbols with
+ * the addresses of the start and end of the exidx table, so returning the
+ * address and count of elements is pretty straighforward.
+ */
+void *
+dl_unwind_find_exidx(const void *pc, int *pcount)
+{
+	extern struct exidx_entry __exidx_start;
+	extern struct exidx_entry __exidx_end;
+
+	*pcount = (int)(&__exidx_end - &__exidx_start);
+	return (&__exidx_start);
+}
+
+#endif	/* __PIC__ */
+