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.

1 files changed, 83 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.arch/aarch64-prologue.c b/gdb/testsuite/gdb.arch/aarch64-prologue.c
new file mode 100644
index 00000000000..aa664f704fb
--- /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;
+}