Update the arm-*-vxworks* support

2019-11-13  Jerome Lambourg  <lambourg@adacore.com>
            Doug Rupp <rupp@adacore.com>
            Olivier Hainque  <hainque@adacore.com>

	gcc/
	* config.gcc: Collapse the arm-vxworks entries into
	a single arm-wrs-vxworks7* one, bpabi based.  Update
	the default cpu from arm8 to armv7-a
	* config/arm/vxworks.h (CC1_SPEC): Simplify, knowing that
	we always use ARM_UNWIND_INFO.
	(DWARF2_UNWIND_INFO): Remove redefinition.
	(ARM_TARGET2_DWARF_FORMAT): Likewise.
	(VXWORKS_PERSONALITY): Define, to "llvm".
	(VXWORKS_EXTRA_LIBS_RTP): Define, to "-lllvm".

	libgcc/
	* config.host: Collapse the arm-vxworks entries into
	a single arm-wrs-vxworks7* one.
	* config/arm/unwind-arm-vxworks.c: Update comments.  Provide
	__gnu_Unwind_Find_exidx and a weak dummy __cxa_type_match for
	kernel modules, to be overriden by libstdc++ when we link with
	it.  Rely on externally provided __exidx_start/end.

Co-Authored-By: Doug Rupp <rupp@adacore.com>
Co-Authored-By: Olivier Hainque <hainque@adacore.com>

From-SVN: r278253

3 files changed, 71 insertions, 21 deletions

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index dfb30a6..dfc842d 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,14 @@
+2019-11-14  Jerome Lambourg  <lambourg@adacore.com>
+	    Doug Rupp <rupp@adacore.com>
+	    Olivier Hainque  <hainque@adacore.com>
+
+	* config.host: Collapse the arm-vxworks entries into
+	a single arm-wrs-vxworks7* one.
+	* config/arm/unwind-arm-vxworks.c: Update comments.  Provide
+	__gnu_Unwind_Find_exidx and a weak dummy __cxa_type_match for
+	kernel modules, to be overriden by libstdc++ when we link with
+	it.  Rely on externally provided __exidx_start/end.
+
 2019-11-14  Doug Rupp  <rupp@adacore.com>
 	    Olivier Hainque  <hainque@adacore.com>
 
diff --git a/libgcc/config.host b/libgcc/config.host
index 1c8d63b..3035168 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -438,18 +438,12 @@ arc*-*-linux*)
 	extra_parts="$extra_parts crttls.o"
 	md_unwind_header=arc/linux-unwind.h
 	;;
-arm-wrs-vxworks|arm-wrs-vxworks7)
-	tmake_file="$tmake_file arm/t-arm arm/t-elf t-softfp-sfdf t-softfp-excl arm/t-softfp t-softfp"
+arm-wrs-vxworks7*)
+	tmake_file="$tmake_file arm/t-arm arm/t-elf arm/t-bpabi arm/t-vxworks7"
+        tmake_file="$tmake_file t-softfp-sfdf t-softfp-excl arm/t-softfp t-softfp"
+	tm_file="$tm_file arm/bpabi-lib.h"
+	unwind_header=config/arm/unwind-arm.h
 	extra_parts="$extra_parts crti.o crtn.o"
-	case ${host} in
-	*-*-vxworks7)
-	  # Note that arm/t-bpabi will reset the LIB2ADDEH macro.
-	  # This is intentional.
-	  tmake_file="$tmake_file arm/t-bpabi arm/t-vxworks7"
-	  tm_file="$tm_file arm/bpabi-lib.h"
-	  unwind_header=config/arm/unwind-arm.h
-	  ;;
-	esac
 	;;
 arm*-*-freebsd*)                # ARM FreeBSD EABI
 	tmake_file="${tmake_file} arm/t-arm t-fixedpoint-gnu-prefix arm/t-elf"
diff --git a/libgcc/config/arm/unwind-arm-vxworks.c b/libgcc/config/arm/unwind-arm-vxworks.c
index 03d753d..6fccf10 100644
--- a/libgcc/config/arm/unwind-arm-vxworks.c
+++ b/libgcc/config/arm/unwind-arm-vxworks.c
@@ -1,4 +1,4 @@
-/* Support for ARM EABI unwinding in VxWorks Downloadable Kernel Modules.
+/* Support for ARM EABI unwinding on VxWorks Downloadable Kernel Modules.
    Copyright (C) 2017-2019 Free Software Foundation, Inc.
 
    This file is free software; you can redistribute it and/or modify it
@@ -20,14 +20,59 @@
    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined(__vxworks) && !defined (__RTP__)
-/* Vxworks for ARM uses __gnu_Unwind_Find_exidx to retrieve the exception
-   table for downloadable kernel modules.  As those modules are only partially
-   linked, the linker won't generate __exidx_start|end, but the two symbols
-   are still used in alternate paths from unwind-arm-common.inc.
+/* The common unwinding code refers to __gnu_Unwind_Find_exidx and
+   __cxa_type_match symbols, which are not in VxWorks kernels on ARM,
+   now llvm based.
+
+   While the common code works just fine for RTPs thanks to weak references
+   and proper positioning of __exidx_start/end from linker scripts, we need
+   symbol definitions for kernel modules.  */
+
+#ifndef __RTP__
+
+#include <private/moduleLibP.h>
+
+/* __gnu_Unwind_Find_exidx.  See if we can use _func_moduleExidxGet to
+   refine whatever we have in __exidx_start and __exidx_end.  */
+
+typedef struct
+{
+  UINT32 fnoffset;
+  UINT32 content;
+} __EIT_entry;
+
+extern __EIT_entry __exidx_start;
+extern __EIT_entry __exidx_end;
+
+__EIT_entry *
+__gnu_Unwind_Find_exidx (void *pc, int *nrec)
+{
+  __EIT_entry *pstart = 0;
+  __EIT_entry *pend = 0;
+
+  if (_func_moduleExidxGet != NULL)
+    _func_moduleExidxGet (pc,
+			  (void *) &__exidx_start, (void *) &__exidx_end,
+			  (void **) &pstart, (void **) &pend);
+
+  if (!pstart)
+    {
+      pstart = &__exidx_start;
+      pend = &__exidx_end;
+    }
+
+  *nrec = pend - pstart;
+
+  return pstart;
+}
+
+/* __cxa_type_match.  A dummy version to be overridden by the libstdc++ one
+ when we link with it.  */
+
+void * __attribute__((weak))
+__cxa_type_match ()
+{
+  return (void *) 0;
+}
 
-   As we don't rely on them, but still need the symbols, we define dummy
-   values here.  */
-void *__exidx_start __attribute__((__visibility__ ("hidden")));
-void *__exidx_end __attribute__((__visibility__ ("hidden")));
 #endif