[gdb/testsuite] Add gdb.arch/ppc64-break-on-_exit.exp

Add a regression test-case for commit a50bdb99afe "[gdb/tdep, rs6000] Don't
skip system call in skip_prologue":
- set a breakpoint on a local copy of glibc's _exit, and
- verify that it triggers.

The test-case uses an assembly file by default, but also has the possibility
to use a C source file instead.

Tested on ppc64le-linux.  Verified that the test-case fails without
aforementioned commit, and passes with the commit.  Both with assembly
and C source.

4 files changed, 303 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.arch/ppc64-break-on-_exit-main.c b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit-main.c
new file mode 100644
index 0000000..7725314
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit-main.c
@@ -0,0 +1,27 @@
+/* This file is part of GDB, the GNU debugger.
+
+   Copyright 2021 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 <unistd.h>
+
+__thread int __libc_errno;
+
+int
+main ()
+{
+  _exit (22);
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c
new file mode 100644
index 0000000..8638a7a
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c
@@ -0,0 +1,112 @@
+/* This file is part of GDB, the GNU debugger.
+
+   Copyright 2021 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 was generated from glibc's 2.31 _exit.c, by doing a glibc build
+   on ppc64le-linux, copying the command line, adding -g0 -save-temps and
+   recuding the _exit.i file.  */
+
+void _exit (int status);
+
+extern __thread int __libc_errno;
+
+void
+_exit (int status)
+{
+  while (1)
+    {
+      ({
+	long int sc_err __attribute__ ((unused));
+	long int sc_ret
+	  = ({
+	      register long int r0 __asm__ ("r0");
+	      register long int r3 __asm__ ("r3");
+	      register long int r4 __asm__ ("r4");
+	      register long int r5 __asm__ ("r5");
+	      register long int r6 __asm__ ("r6");
+	      register long int r7 __asm__ ("r7");
+	      register long int r8 __asm__ ("r8");
+	      long int arg1 = (long int) (status);
+
+	      r0 = 234;
+
+	      extern void __illegally_sized_syscall_arg1 (void);
+	      if (__builtin_classify_type (status) != 5 && sizeof (status) > 8)
+		__illegally_sized_syscall_arg1 ();
+
+	      r3 = arg1;
+	      __asm__ __volatile__ ("sc\n\t" "mfcr  %0\n\t" "0:"
+				    : "=&r" (r0), "=&r" (r3), "=&r" (r4),
+				      "=&r" (r5), "=&r" (r6), "=&r" (r7),
+				      "=&r" (r8) : "0" (r0), "1" (r3)
+				    : "r9", "r10", "r11", "r12", "cr0", "ctr", "memory");
+	      sc_err = r0;
+
+	      r3;
+	    });
+
+	if (((void) (sc_ret), __builtin_expect ((sc_err) & (1 << 28), 0)))
+	  {
+	    (__libc_errno = ((sc_ret)));
+	    sc_ret = -1L;
+	  }
+
+	sc_ret;
+      });
+
+      ({
+	long int sc_err __attribute__ ((unused));
+	long int sc_ret
+	  = ({
+	      register long int r0 __asm__ ("r0");
+	      register long int r3 __asm__ ("r3");
+	      register long int r4 __asm__ ("r4");
+	      register long int r5 __asm__ ("r5");
+	      register long int r6 __asm__ ("r6");
+	      register long int r7 __asm__ ("r7");
+	      register long int r8 __asm__ ("r8");
+	      long int arg1 = (long int) (status);
+
+	      r0 = 1;
+
+	      extern void __illegally_sized_syscall_arg1 (void);
+	      if (__builtin_classify_type (status) != 5 && sizeof (status) > 8)
+		__illegally_sized_syscall_arg1 ();
+
+	      r3 = arg1;
+	      __asm__ __volatile__ ("sc\n\t" "mfcr  %0\n\t" "0:"
+				    : "=&r" (r0), "=&r" (r3), "=&r" (r4),
+				      "=&r" (r5), "=&r" (r6), "=&r" (r7),
+				      "=&r" (r8) : "0" (r0), "1" (r3)
+				    : "r9", "r10", "r11", "r12", "cr0", "ctr", "memory");
+	      sc_err = r0;
+
+	      r3;
+	    });
+
+	if (((void) (sc_ret), __builtin_expect ((sc_err) & (1 << 28), 0)))
+	  {
+	    (__libc_errno = ((sc_ret)));
+	    sc_ret = -1L;
+	  }
+
+	sc_ret;
+      });
+
+
+      asm (".long 0");
+    }
+}
diff --git a/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.exp b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.exp
new file mode 100644
index 0000000..6b76d26
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.exp
@@ -0,0 +1,56 @@
+# Copyright 2021 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/>.
+
+# Set a breakpoint on a local copy of glibc's _exit, and verify that it
+# triggers.  The function does a syscall immediately after the prologue, and
+# if the breakpoint is set past the syscall due to faulty prologue skipping,
+# the breakpoint will not trigger.
+#
+# In particular, we're trying to excercise the instruction analysis
+# functionality of prologue skipping.  If non-minimal symbols are
+# read, then that functionality might not be used because f.i.
+# line-info is used instead.  So, we use nodebug.
+
+if {![istarget "powerpc*"] || ![is_lp64_target]} {
+    unsupported "Not powerpc64"
+    return
+}
+
+set flags { nodebug }
+if [info exists COMPILE] {
+    standard_testfile .c -main.c
+    lappend flags optimize=-O2
+    lappend flags additional_flags=-fno-stack-protector
+    lappend flags additional_flags=-mlong-double-128
+    lappend flags additional_flags=-fpic
+    lappend flags additional_flags=-ftls-model=initial-exec
+} else {
+    standard_testfile .s -main.c
+}
+
+if { [prepare_for_testing "failed to prepare" ${testfile} \
+	  [list $srcfile $srcfile2] $flags] } {
+    return -1
+}
+
+if ![runto_main] then {
+    return 0
+}
+
+gdb_breakpoint "_exit"
+
+# If the skip_prologue analysis of _exit is too eager, we may not hit the
+# breakpoint.
+gdb_continue_to_breakpoint "_exit" "_exit \\(\\).*"
diff --git a/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.s b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.s
new file mode 100644
index 0000000..37a9ace
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.s
@@ -0,0 +1,108 @@
+/* This file is part of GDB, the GNU debugger.
+
+   Copyright 2021 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 was generated from ppc64-break-on-_exit.c.  */
+
+	.file	"ppc64-break-on-_exit.c"
+	.abiversion 2
+	.section	".text"
+	.align 2
+	.p2align 4,,15
+	.globl _exit
+	.type	_exit, @function
+_exit:
+.LCF0:
+0:	addis 2,12,.TOC.-.LCF0@ha
+	addi 2,2,.TOC.-.LCF0@l
+	.localentry	_exit,.-_exit
+	addis 9,2,__libc_errno@got@tprel@ha
+	std 31,-8(1)
+	mr 31,3
+	std 30,-16(1)
+	li 0,234
+	ld 9,__libc_errno@got@tprel@l(9)
+	mr 3,31
+	add 30,9,__libc_errno@tls
+#APP
+ # 28 "src/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c" 1
+	sc
+	mfcr  0
+	0:
+ # 0 "" 2
+#NO_APP
+	andis. 9,0,0x1000
+	mr 9,3
+	li 0,1
+	mr 3,31
+	bne 0,.L13
+	.p2align 4,,15
+.L2:
+#APP
+ # 67 "src/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c" 1
+	sc
+	mfcr  0
+	0:
+ # 0 "" 2
+#NO_APP
+	andis. 9,0,0x1000
+	bne 0,.L14
+.L3:
+#APP
+ # 87 "src/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c" 1
+	.long 0
+ # 0 "" 2
+#NO_APP
+.L15:
+	li 0,234
+	mr 3,31
+#APP
+ # 28 "src/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c" 1
+	sc
+	mfcr  0
+	0:
+ # 0 "" 2
+#NO_APP
+	andis. 9,0,0x1000
+	mr 9,3
+	li 0,1
+	mr 3,31
+	beq 0,.L2
+.L13:
+	stw 9,0(30)
+#APP
+ # 67 "src/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c" 1
+	sc
+	mfcr  0
+	0:
+ # 0 "" 2
+#NO_APP
+	andis. 9,0,0x1000
+	beq 0,.L3
+	.p2align 4,,15
+.L14:
+	stw 3,0(30)
+#APP
+ # 87 "src/gdb/testsuite/gdb.arch/ppc64-break-on-_exit.c" 1
+	.long 0
+ # 0 "" 2
+#NO_APP
+	b .L15
+	.long 0
+	.byte 0,0,0,0,0,2,0,0
+	.size	_exit,.-_exit
+	.ident	"GCC: (SUSE Linux) 7.5.0"
+	.section	.note.GNU-stack,"",@progbits