package/gcc: backport xtensa trap pattern for 5.x

gcc 5.x uses trap pattern extensively to mark locations where program
execution should never get. Default pattern implementation emits a call
to 'abort' function. This function however is not always available, e.g.
it's not available for the libc dynamic linker. Backport implementation
of the trap pattern for xtensa that does not result in a call to
'abort'.

Fixes:
  http://autobuild.buildroot.net/results/0fbcc4475545904bf88f25a3bdf3ee552bf4960e
  http://autobuild.buildroot.net/results/cb7f5bdfac615d774f3bcd1b802f8d74460bc557
  http://autobuild.buildroot.net/results/cf3dc9ae4f74ff28b285f1a862b71d96384d7651

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/gcc/5.4.0/875-xtensa-implement-trap-pattern.patch

@@ -0,0 +1,67 @@
+From 2b4b5775554c91a63ccae4ee566db696b633652e Mon Sep 17 00:00:00 2001
+From: jcmvbkbc <jcmvbkbc@138bc75d-0d04-0410-961f-82ee72b054a4>
+Date: Wed, 10 Jun 2015 15:07:40 +0000
+Subject: [PATCH] xtensa: implement trap pattern
+
+2015-06-10  Max Filippov  <jcmvbkbc@gmail.com>
+gcc/
+	* config/xtensa/xtensa.h (TARGET_DEBUG): New definition.
+	* config/xtensa/xtensa.md (define_attr "type"): New type "trap".
+	(define_insn "trap"): New definition.
+
+Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
+
+git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@224330 138bc75d-0d04-0410-961f-82ee72b054a4
+---
+ gcc/config/xtensa/xtensa.h  |  1 +
+ gcc/config/xtensa/xtensa.md | 15 ++++++++++++++-
+ 2 files changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/gcc/config/xtensa/xtensa.h b/gcc/config/xtensa/xtensa.h
+index 615f741..fb8702c 100644
+--- a/gcc/config/xtensa/xtensa.h
++++ b/gcc/config/xtensa/xtensa.h
+@@ -67,6 +67,7 @@ extern unsigned xtensa_current_frame_size;
+ #define TARGET_THREADPTR	XCHAL_HAVE_THREADPTR
+ #define TARGET_LOOPS	        XCHAL_HAVE_LOOPS
+ #define TARGET_WINDOWED_ABI	(XSHAL_ABI == XTHAL_ABI_WINDOWED)
++#define TARGET_DEBUG		XCHAL_HAVE_DEBUG
+ 
+ #define TARGET_DEFAULT \
+   ((XCHAL_HAVE_L32R	? 0 : MASK_CONST16) |				\
+diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
+index 6d84384..a577aa3 100644
+--- a/gcc/config/xtensa/xtensa.md
++++ b/gcc/config/xtensa/xtensa.md
+@@ -86,7 +86,7 @@
+ ;; Attributes.
+ 
+ (define_attr "type"
+-  "unknown,jump,call,load,store,move,arith,multi,nop,farith,fmadd,fconv,fload,fstore,mul16,mul32,div32,mac16,rsr,wsr,entry"
++  "unknown,jump,call,load,store,move,arith,multi,nop,farith,fmadd,fconv,fload,fstore,mul16,mul32,div32,mac16,rsr,wsr,entry,trap"
+   (const_string "unknown"))
+ 
+ (define_attr "mode"
+@@ -1764,6 +1764,19 @@
+   [(set_attr "length" "0")
+    (set_attr "type" "nop")])
+ 
++(define_insn "trap"
++  [(trap_if (const_int 1) (const_int 0))]
++  ""
++{
++  if (TARGET_DEBUG)
++    return "break\t1, 15";
++  else
++    return (TARGET_DENSITY ? "ill.n" : "ill");
++}
++  [(set_attr "type"	"trap")
++   (set_attr "mode"	"none")
++   (set_attr "length"	"3")])
++
+ ;; Setting up a frame pointer is tricky for Xtensa because GCC doesn't
+ ;; know if a frame pointer is required until the reload pass, and
+ ;; because there may be an incoming argument value in the hard frame
+-- 
+2.1.4
+