[Ada] New port arm-qnx

The QNX system specs for ARM and AARCH64 are identical. It makes more
sense to have it named for the base architecture.

gcc/ada/

	* Makefile.rtl: Rename system-qnx-aarch64.ads to
	system-qnx-arm.ads.
	(AARCH64 QNX section): Modify to handle both arm and arch64.
	* tracebak.c (__QNX__): Add new __ARMEL__ section.
	* sigtramp-arm-qnx.c: New file.
	* libgnat/system-qnx-aarch64.ads: Renamed to ...
	* libgnat/system-qnx-arm.ads: this.

4 files changed, 174 insertions, 9 deletions

diff --git a/gcc/ada/Makefile.rtl b/gcc/ada/Makefile.rtl
index fde20d4..e4ca894 100644
--- a/gcc/ada/Makefile.rtl
+++ b/gcc/ada/Makefile.rtl
@@ -1493,8 +1493,8 @@ ifeq ($(strip $(filter-out arm% linux-androideabi,$(target_cpu) $(target_os))),)
   LIBRARY_VERSION := $(LIB_VERSION)
 endif
 
-# AARCH64 QNX
-ifeq ($(strip $(filter-out aarch64 %qnx,$(target_cpu) $(target_os))),)
+# ARM and AARCH64 QNX
+ifeq ($(strip $(filter-out arm aarch64 %qnx,$(target_cpu) $(target_os))),)
   LIBGNAT_TARGET_PAIRS = \
   a-intnam.ads<libgnarl/a-intnam__qnx.ads \
   a-nallfl.ads<libgnat/a-nallfl__wraplf.ads \
@@ -1511,21 +1511,28 @@ ifeq ($(strip $(filter-out aarch64 %qnx,$(target_cpu) $(target_os))),)
   g-soliop.ads<libgnat/g-soliop__qnx.ads \
   $(ATOMICS_TARGET_PAIRS) \
   $(ATOMICS_BUILTINS_TARGET_PAIRS) \
-  $(GNATRTL_128BIT_PAIRS) \
-  system.ads<libgnat/system-qnx-aarch64.ads
+  system.ads<libgnat/system-qnx-arm.ads
 
   TOOLS_TARGET_PAIRS = indepsw.adb<indepsw-gnu.adb
 
-  EXTRA_GNATRTL_NONTASKING_OBJS = $(GNATRTL_128BIT_OBJS)
   EXTRA_GNATRTL_TASKING_OBJS=s-qnx.o
-  EXTRA_LIBGNAT_OBJS+=sigtramp-qnx.o
+  ifeq ($(strip $(filter-out arm%, $(target_cpu))),)
+     EH_MECHANISM=-arm
+     SIGTRAMP_OBJ=sigtramp-arm-qnx.o
+  else
+     EH_MECHANISM=-gcc
+     SIGTRAMP_OBJ=sigtramp-qnx.o
+     LIBGNAT_TARGET_PAIRS += $(GNATRTL_128BIT_PAIRS)
+     EXTRA_GNATRTL_NONTASKING_OBJS = $(GNATRTL_128BIT_OBJS)
+     # Temporarily restrict shared library build to aarch64 (V303-025)
+     GNATLIB_SHARED = gnatlib-shared-dual
+  endif
+  EXTRA_LIBGNAT_OBJS+=$(SIGTRAMP_OBJ)
   EXTRA_LIBGNAT_SRCS+=sigtramp.h
-  EH_MECHANISM=-gcc
 
   SO_OPTS= -shared-libgcc -Wl,-soname,
   MISCLIB= -lsocket
   THREADSLIB=
-  GNATLIB_SHARED = gnatlib-shared-dual
   LIBRARY_VERSION := $(LIB_VERSION)
 endif
 
diff --git a/gcc/ada/libgnat/system-qnx-aarch64.ads b/gcc/ada/libgnat/system-qnx-arm.ads
index 7e61ae3..5f4b90e 100644
--- a/gcc/ada/libgnat/system-qnx-aarch64.ads
+++ b/gcc/ada/libgnat/system-qnx-arm.ads
@@ -5,7 +5,7 @@
 --                               S Y S T E M                                --
 --                                                                          --
 --                                 S p e c                                  --
---                         (QNX/Aarch64 Version)                            --
+--                        (QNX-ARM/AARCH64 Version)                         --
 --                                                                          --
 --          Copyright (C) 1992-2022, Free Software Foundation, Inc.         --
 --                                                                          --
diff --git a/gcc/ada/sigtramp-arm-qnx.c b/gcc/ada/sigtramp-arm-qnx.c
new file mode 100644
index 0000000..4d359d7
--- /dev/null
+++ b/gcc/ada/sigtramp-arm-qnx.c
@@ -0,0 +1,155 @@
+/****************************************************************************
+ *                                                                          *
+ *                         GNAT COMPILER COMPONENTS                         *
+ *                                                                          *
+ *                             S I G T R A M P                              *
+ *                                                                          *
+ *                         Asm Implementation File                          *
+ *                                                                          *
+ *           Copyright (C) 2015-2022, Free Software Foundation, Inc.        *
+ *                                                                          *
+ * GNAT is free software;  you can  redistribute it  and/or modify it under *
+ * terms of the  GNU General Public License as published  by the Free Soft- *
+ * ware  Foundation;  either version 3,  or (at your option) any later ver- *
+ * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
+ * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
+ * or FITNESS FOR A PARTICULAR PURPOSE.                                     *
+ *                                                                          *
+ * As a special exception under Section 7 of GPL version 3, you are granted *
+ * additional permissions described in the GCC Runtime Library Exception,   *
+ * version 3.1, as published by the Free Software Foundation.               *
+ *                                                                          *
+ * In particular,  you can freely  distribute your programs  built with the *
+ * GNAT Pro compiler, including any required library run-time units,  using *
+ * any licensing terms  of your choosing.  See the AdaCore Software License *
+ * for full details.                                                        *
+ *                                                                          *
+ * GNAT was originally developed  by the GNAT team at  New York University. *
+ * Extensive contributions were provided by Ada Core Technologies Inc.      *
+ *                                                                          *
+ ****************************************************************************/
+
+/**************************************************
+ * ARM-QNX version of the __gnat_sigtramp service *
+ **************************************************/
+
+#include <ucontext.h>
+
+#include "sigtramp.h"
+/* See sigtramp.h for a general explanation of functionality.  */
+
+/* ----------------------
+   -- General comments --
+   ----------------------
+
+   Stubs are generated from toplevel asms,
+   The general idea is to establish CFA as the sigcontext
+   and state where to find the registers as offsets from there.
+
+   Note that the registers we "restore" here are those to which we have
+   direct access through the system sigcontext structure, which includes
+   only a partial set of the non-volatiles ABI-wise.  */
+
+/* -----------------------------------------
+   -- Protypes for our internal asm stubs --
+   -----------------------------------------
+
+   The registers are expected to be at SIGCONTEXT + 12 (reference the
+   sicontext structure in asm/sigcontext.h which describes the first
+   3 * 4byte fields.)  Even though our symbols will remain local, the
+   prototype claims "extern" and not "static" to prevent compiler complaints
+   about a symbol used but never defined.  */
+
+/* sigtramp stub providing unwind info for common registers.  */
+
+extern void __gnat_sigtramp_common
+  (int signo, void *siginfo, void *sigcontext,
+   __sigtramphandler_t * handler);
+
+void __gnat_sigtramp (int signo, void *si, void *sc,
+                      __sigtramphandler_t * handler)
+     __attribute__((optimize(2)));
+
+void __gnat_sigtramp (int signo, void *si, void *ucontext,
+                      __sigtramphandler_t * handler)
+{
+  struct sigcontext *mcontext = &((ucontext_t *) ucontext)->uc_mcontext;
+
+  __gnat_sigtramp_common (signo, si, mcontext, handler);
+}
+
+/* asm string construction helpers.  */
+
+#define STR(TEXT) #TEXT
+/* stringify expanded TEXT, surrounding it with double quotes.  */
+
+#define S(E) STR(E)
+/* stringify E, which will resolve as text but may contain macros
+   still to be expanded.  */
+
+/* asm (TEXT) outputs <tab>TEXT. These facilitate the output of
+   multiline contents:  */
+#define TAB(S) "\t" S
+#define CR(S)  S "\n"
+
+#undef TCR
+#define TCR(S) TAB(CR(S))
+
+/* Trampoline body block
+   ---------------------  */
+
+#define SIGTRAMP_BODY \
+CR("") \
+TCR("# Allocate frame and also save r2 which is the argument register") \
+TCR("# containing the sigcontext, so that we can restore it during") \
+TCR("# unwinding and thereby load the rest of the desired context.") \
+TCR("stmfd	sp!, {r2, r3, lr}") \
+TCR("# The unwinder undo's these operations in reverse order so starting") \
+TCR("# from bottom, restore r2 from the current vsp location, move r2 into") \
+TCR("# the vsp, add 12 bytes to get the start of the register save area") \
+TCR("# then restore the 15 general purpose registers of the frame which") \
+TCR("# raised the signal.") \
+TCR(".save {r0-r15}") \
+TCR(".pad #12") \
+TCR(".movsp r2") \
+TCR(".save {r2}") \
+TCR("# Call the real handler. The signo, siginfo and sigcontext") \
+TCR("# arguments are the same as those we received in r0, r1 and r2.") \
+TCR("blx	r3") \
+TCR("# Restore our callee-saved items, release our frame and return") \
+TCR("# (should never get here!).") \
+TCR("ldmfd	sp, {r2, r3, pc}")
+
+/* Symbol definition block
+   -----------------------  */
+
+#define SIGTRAMP_START(SYM) \
+CR("# " S(SYM) " unwind trampoline") \
+TCR(".type " S(SYM) ", %function") \
+CR("") \
+CR(S(SYM) ":") \
+TCR(".fnstart")
+
+/* Symbol termination block
+   ------------------------  */
+
+#define SIGTRAMP_END(SYM) \
+CR(".fnend") \
+TCR(".size " S(SYM) ", .-" S(SYM))
+
+/*----------------------------
+  -- And now, the real code --
+  ---------------------------- */
+
+/* Text section start.  The compiler isn't aware of that switch.  */
+
+asm (".text\n"
+     TCR(".align 2"));
+
+/* sigtramp stub for common registers.  */
+
+#define TRAMP_COMMON __gnat_sigtramp_common
+
+asm (SIGTRAMP_START(TRAMP_COMMON));
+asm (SIGTRAMP_BODY);
+asm (SIGTRAMP_END(TRAMP_COMMON));
diff --git a/gcc/ada/tracebak.c b/gcc/ada/tracebak.c
index 6cc5d30..f4e739d 100644
--- a/gcc/ada/tracebak.c
+++ b/gcc/ada/tracebak.c
@@ -555,6 +555,9 @@ is_return_from(void *symbol_addr, void *ret_addr)
 
 #if defined (__aarch64__)
 #define PC_ADJUST -4
+#elif defined (__ARMEL__)
+#define PC_ADJUST -2
+#define USING_ARM_UNWINDING 1
 #else
 #error Unhandled QNX architecture.
 #endif