AArch64: Allow additional sizes in prologue

When saving registers to the stack at the start of a function, not all state
needs to be saved. For example, only the first 64bits of float registers need
saving.  However, a program may choose to store extra state if it wishes,
there is nothing preventing it doing so.

The aarch64_analyze_prologue will error if it detects extra state being
stored.  Relex this restriction.

Tested via aarch64-prologue test.

gdb/ChangeLog:

	* aarch64-tdep.c (aarch64_analyze_prologue): Allow any valid
	register sizes.

gdb/testsuite/ChangeLog:

	* gdb.arch/aarch64-prologue.c: New test.
	* gdb.arch/aarch64-prologue.exp: New file.

3 files changed, 124 insertions, 0 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index e4b9616..6c80a69 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-08-14  Alan Hayward  <alan.hayward@arm.com>
+
+	* gdb.arch/aarch64-prologue.c: New test.
+	* gdb.arch/aarch64-prologue.exp: New file.
+
 2019-08-13  Tom de Vries  <tdevries@suse.de>
 
 	* gdb.gdb/selftest.exp (send ^C to child process again): Accept also
diff --git a/gdb/testsuite/gdb.arch/aarch64-prologue.c b/gdb/testsuite/gdb.arch/aarch64-prologue.c
new file mode 100644
index 0000000..aa664f7
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-prologue.c
@@ -0,0 +1,83 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2019 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+
+extern void excessiveprologue ();
+
+void
+innerfunc ()
+{
+  printf ("inner\n");
+}
+
+/* excessiveprologue saves to the stack in multiple ways.  */
+
+asm ("\t.section .gnu.sgstubs,\"ax\",%progbits\n"
+     "\t.global excessiveprologue\n"
+     "\t.type excessiveprologue, %function\n"
+     "excessiveprologue:\n"
+     "\tstp	x29, x30, [sp, #-208]!\n"
+     "\tmov	x29, sp\n"
+     "\tstp	w0,w1,[sp,16]\n"
+     "\tstp	x2,x3,[sp,24]\n"
+     "\tstr	w4,[sp,40]\n"
+     "\tstr	x5,[sp,48]\n"
+     "\tstur	w6,[sp,52]\n"
+     "\tstur	x7,[sp,56]\n"
+     "\tstp	s0,s1,[sp,64]\n"
+     "\tstp	d2,d3,[sp,72]\n"
+     "\tstp	q4,q5,[sp,96]\n"
+     "\tstr	b6,[sp,128]\n"
+     "\tstr	h7,[sp,132]\n"
+     "\tstr	s8,[sp,136]\n"
+     "\tstr	d9,[sp,140]\n"
+     "\tstr	q10,[sp,148]\n"
+     "\tstur	b11,[sp,164]\n"
+     "\tstur	h12,[sp,160]\n"
+     "\tstur	s13,[sp,172]\n"
+     "\tstur	d14,[sp,176]\n"
+     "\tstur	q15,[sp,184]\n"
+     "\tbl innerfunc\n"
+     "\tldp	w0,w1,[sp,16]\n"
+     "\tldp	x2,x3,[sp,24]\n"
+     "\tldr	w4,[sp,40]\n"
+     "\tldr	x5,[sp,48]\n"
+     "\tldur	w6,[sp,52]\n"
+     "\tldur	x7,[sp,56]\n"
+     "\tldp	s0,s1,[sp,64]\n"
+     "\tldp	d2,d3,[sp,72]\n"
+     "\tldp	q4,q5,[sp,96]\n"
+     "\tldr	b6,[sp,128]\n"
+     "\tldr	h7,[sp,132]\n"
+     "\tldr	s8,[sp,136]\n"
+     "\tldr	d9,[sp,140]\n"
+     "\tldr	q10,[sp,148]\n"
+     "\tldur	b11,[sp,164]\n"
+     "\tldur	h12,[sp,160]\n"
+     "\tldur	s13,[sp,172]\n"
+     "\tldur	d14,[sp,176]\n"
+     "\tldur	q15,[sp,184]\n"
+     "\tldp	x29, x30, [sp], #208\n"
+     "ret\n");
+
+int
+main (void)
+{
+  excessiveprologue ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.arch/aarch64-prologue.exp b/gdb/testsuite/gdb.arch/aarch64-prologue.exp
new file mode 100644
index 0000000..e31261a
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-prologue.exp
@@ -0,0 +1,36 @@
+# Copyright 2019 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+if {![is_aarch64_target]} {
+    verbose "Skipping ${gdb_test_file_name}."
+    return 1
+}
+
+standard_testfile
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile {nodebug}]} {
+    return -1
+}
+
+if ![runto_main] {
+   untested "could not run to main"
+   return -1
+}
+
+# Ensure gdb can break at excessiveprologue then continue.
+gdb_breakpoint "excessiveprologue"
+gdb_continue_to_breakpoint "excessiveprologue"
+gdb_continue_to_end "excessiveprologue" "continue" 1