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[patch] reverse: Do not run-away on jmp-only instr. function


Hi,

formerly: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54405

reverse-next sometimes run-aways:

 reverse-next
-
-No more reverse-execution history.
-main () at gdb.reverse/singlejmp-reverse.c:35
-35       v = 1;
-(gdb) FAIL: gdb.reverse/singlejmp-reverse.exp: reverse-next
+36       f ();
+(gdb) PASS: gdb.reverse/singlejmp-reverse.exp: reverse-next

No regressions on {x86_64,x86_64-m32,i686}-fedora18-linux-gnu.


Thanks,
Jan


gdb/
2012-09-12  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR 14548
	* infrun.c (handle_inferior_event): Do not reverse-continue back to the
	function start if we are already at function start.

gdb/testsuite/
2012-09-12  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR 14548
	* gdb.reverse/singlejmp-reverse.S: New file.
	* gdb.reverse/singlejmp-reverse.c: New file.
	* gdb.reverse/singlejmp-reverse.exp: New file.

diff --git a/gdb/infrun.c b/gdb/infrun.c
index cbab993..0add270 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -4902,14 +4902,19 @@ process_event_stop_test:
 
 	  if (execution_direction == EXEC_REVERSE)
 	    {
-	      struct symtab_and_line sr_sal;
-
-	      /* Normal function call return (static or dynamic).  */
-	      init_sal (&sr_sal);
-	      sr_sal.pc = ecs->stop_func_start;
-	      sr_sal.pspace = get_frame_program_space (frame);
-	      insert_step_resume_breakpoint_at_sal (gdbarch,
-						    sr_sal, null_frame_id);
+	      /* Do not run away if we are already at function start - the
+		 function contains only one (jump) instruction.  */
+	      if (ecs->stop_func_start != stop_pc)
+		{
+		  struct symtab_and_line sr_sal;
+
+		  /* Normal function call return (static or dynamic).  */
+		  init_sal (&sr_sal);
+		  sr_sal.pc = ecs->stop_func_start;
+		  sr_sal.pspace = get_frame_program_space (frame);
+		  insert_step_resume_breakpoint_at_sal (gdbarch,
+							sr_sal, null_frame_id);
+		}
 	    }
 	  else
 	    insert_step_resume_breakpoint_at_caller (frame);
diff --git a/gdb/testsuite/gdb.reverse/singlejmp-reverse.S b/gdb/testsuite/gdb.reverse/singlejmp-reverse.S
new file mode 100644
index 0000000..71f18e7
--- /dev/null
+++ b/gdb/testsuite/gdb.reverse/singlejmp-reverse.S
@@ -0,0 +1,284 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2012 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 source file was generated by:
+   gcc -o gdb.reverse/singlejmp-reverse.S gdb.reverse/singlejmp-reverse.c -Wall -S -dA -O2 -g
+   */
+
+	.file	"singlejmp-reverse.c"
+	.text
+.Ltext0:
+	.p2align 4,,15
+	.type	g, @function
+g:
+.LFB0:
+	.file 1 "gdb.reverse/singlejmp-reverse.c"
+	# gdb.reverse/singlejmp-reverse.c:22
+	.loc 1 22 0
+	.cfi_startproc
+	# basic block 2
+	# gdb.reverse/singlejmp-reverse.c:23
+	.loc 1 23 0
+	movl	$2, v(%rip)
+	# gdb.reverse/singlejmp-reverse.c:24
+	.loc 1 24 0
+	ret
+	.cfi_endproc
+.LFE0:
+	.size	g, .-g
+	.p2align 4,,15
+	.type	f, @function
+f:
+.LFB1:
+	# gdb.reverse/singlejmp-reverse.c:28
+	.loc 1 28 0
+	.cfi_startproc
+	# basic block 2
+	# gdb.reverse/singlejmp-reverse.c:29
+	.loc 1 29 0
+	jmp	g
+	.cfi_endproc
+.LFE1:
+	.size	f, .-f
+	.section	.text.startup,"ax",@progbits
+	.p2align 4,,15
+	.globl	main
+	.type	main, @function
+main:
+.LFB2:
+	# gdb.reverse/singlejmp-reverse.c:34
+	.loc 1 34 0
+	.cfi_startproc
+	# basic block 2
+	# gdb.reverse/singlejmp-reverse.c:35
+	.loc 1 35 0
+	movl	$1, v(%rip)
+	# gdb.reverse/singlejmp-reverse.c:36
+	.loc 1 36 0
+	call	f
+	# gdb.reverse/singlejmp-reverse.c:37
+	.loc 1 37 0
+	movl	$3, v(%rip)
+	# gdb.reverse/singlejmp-reverse.c:39
+	.loc 1 39 0
+	xorl	%eax, %eax
+	ret
+	.cfi_endproc
+.LFE2:
+	.size	main, .-main
+	.comm	v,4,4
+	.text
+.Letext0:
+	.section	.debug_info,"",@progbits
+.Ldebug_info0:
+	.long	0xa0	# Length of Compilation Unit Info
+	.value	0x2	# DWARF version number
+	.long	.Ldebug_abbrev0	# Offset Into Abbrev. Section
+	.byte	0x8	# Pointer Size (in bytes)
+	.uleb128 0x1	# (DIE (0xb) DW_TAG_compile_unit)
+	.long	.LASF0	# DW_AT_producer: "GNU C 4.6.4 20120911 (prerelease)"
+	.byte	0x1	# DW_AT_language
+	.long	.LASF1	# DW_AT_name: "gdb.reverse/singlejmp-reverse.c"
+	.long	.LASF2	# DW_AT_comp_dir: ""
+	.quad	0	# DW_AT_low_pc
+	.quad	0	# DW_AT_entry_pc
+	.long	.Ldebug_ranges0+0	# DW_AT_ranges
+	.long	.Ldebug_line0	# DW_AT_stmt_list
+	.uleb128 0x2	# (DIE (0x31) DW_TAG_subprogram)
+	.ascii "g\0"	# DW_AT_name
+	.byte	0x1	# DW_AT_decl_file (gdb.reverse/singlejmp-reverse.c)
+	.byte	0x15	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_prototyped
+	.quad	.LFB0	# DW_AT_low_pc
+	.quad	.LFE0	# DW_AT_high_pc
+	.byte	0x2	# DW_AT_frame_base
+	.byte	0x77	# DW_OP_breg7
+	.sleb128 8
+	.uleb128 0x2	# (DIE (0x4a) DW_TAG_subprogram)
+	.ascii "f\0"	# DW_AT_name
+	.byte	0x1	# DW_AT_decl_file (gdb.reverse/singlejmp-reverse.c)
+	.byte	0x1b	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_prototyped
+	.quad	.LFB1	# DW_AT_low_pc
+	.quad	.LFE1	# DW_AT_high_pc
+	.byte	0x2	# DW_AT_frame_base
+	.byte	0x77	# DW_OP_breg7
+	.sleb128 8
+	.uleb128 0x3	# (DIE (0x63) DW_TAG_subprogram)
+	.byte	0x1	# DW_AT_external
+	.long	.LASF3	# DW_AT_name: "main"
+	.byte	0x1	# DW_AT_decl_file (gdb.reverse/singlejmp-reverse.c)
+	.byte	0x21	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_prototyped
+	.long	0x83	# DW_AT_type
+	.quad	.LFB2	# DW_AT_low_pc
+	.quad	.LFE2	# DW_AT_high_pc
+	.byte	0x2	# DW_AT_frame_base
+	.byte	0x77	# DW_OP_breg7
+	.sleb128 8
+	.uleb128 0x4	# (DIE (0x83) DW_TAG_base_type)
+	.byte	0x4	# DW_AT_byte_size
+	.byte	0x5	# DW_AT_encoding
+	.ascii "int\0"	# DW_AT_name
+	.uleb128 0x5	# (DIE (0x8a) DW_TAG_variable)
+	.ascii "v\0"	# DW_AT_name
+	.byte	0x1	# DW_AT_decl_file (gdb.reverse/singlejmp-reverse.c)
+	.byte	0x12	# DW_AT_decl_line
+	.long	0x9e	# DW_AT_type
+	.byte	0x1	# DW_AT_external
+	.byte	0x9	# DW_AT_location
+	.byte	0x3	# DW_OP_addr
+	.quad	v
+	.uleb128 0x6	# (DIE (0x9e) DW_TAG_volatile_type)
+	.long	0x83	# DW_AT_type
+	.byte	0	# end of children of DIE 0xb
+	.section	.debug_abbrev,"",@progbits
+.Ldebug_abbrev0:
+	.uleb128 0x1	# (abbrev code)
+	.uleb128 0x11	# (TAG: DW_TAG_compile_unit)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x25	# (DW_AT_producer)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x13	# (DW_AT_language)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x1b	# (DW_AT_comp_dir)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x52	# (DW_AT_entry_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x55	# (DW_AT_ranges)
+	.uleb128 0x6	# (DW_FORM_data4)
+	.uleb128 0x10	# (DW_AT_stmt_list)
+	.uleb128 0x6	# (DW_FORM_data4)
+	.byte	0
+	.byte	0
+	.uleb128 0x2	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0	# DW_children_no
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0xc	# (DW_FORM_flag)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0xa	# (DW_FORM_block1)
+	.byte	0
+	.byte	0
+	.uleb128 0x3	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0	# DW_children_no
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0xc	# (DW_FORM_flag)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0xc	# (DW_FORM_flag)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0xa	# (DW_FORM_block1)
+	.byte	0
+	.byte	0
+	.uleb128 0x4	# (abbrev code)
+	.uleb128 0x24	# (TAG: DW_TAG_base_type)
+	.byte	0	# DW_children_no
+	.uleb128 0xb	# (DW_AT_byte_size)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3e	# (DW_AT_encoding)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.byte	0
+	.byte	0
+	.uleb128 0x5	# (abbrev code)
+	.uleb128 0x34	# (TAG: DW_TAG_variable)
+	.byte	0	# DW_children_no
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0xc	# (DW_FORM_flag)
+	.uleb128 0x2	# (DW_AT_location)
+	.uleb128 0xa	# (DW_FORM_block1)
+	.byte	0
+	.byte	0
+	.uleb128 0x6	# (abbrev code)
+	.uleb128 0x35	# (TAG: DW_TAG_volatile_type)
+	.byte	0	# DW_children_no
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.byte	0
+	.byte	0
+	.byte	0
+	.section	.debug_aranges,"",@progbits
+	.long	0x3c	# Length of Address Ranges Info
+	.value	0x2	# DWARF Version
+	.long	.Ldebug_info0	# Offset of Compilation Unit Info
+	.byte	0x8	# Size of Address
+	.byte	0	# Size of Segment Descriptor
+	.value	0	# Pad to 16 byte boundary
+	.value	0
+	.quad	.Ltext0	# Address
+	.quad	.Letext0-.Ltext0	# Length
+	.quad	.LFB2	# Address
+	.quad	.LFE2-.LFB2	# Length
+	.quad	0
+	.quad	0
+	.section	.debug_ranges,"",@progbits
+.Ldebug_ranges0:
+	.quad	.Ltext0	# Offset 0
+	.quad	.Letext0
+	.quad	.LFB2	# Offset 0x10
+	.quad	.LFE2
+	.quad	0
+	.quad	0
+	.section	.debug_line,"",@progbits
+.Ldebug_line0:
+	.section	.debug_str,"MS",@progbits,1
+.LASF3:
+	.string	"main"
+.LASF0:
+	.string	"GNU C 4.6.4 20120911 (prerelease)"
+.LASF2:
+	.string	""
+.LASF1:
+	.string	"gdb.reverse/singlejmp-reverse.c"
+	.ident	"GCC: (GNU) 4.6.4 20120911 (prerelease)"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/gdb/testsuite/gdb.reverse/singlejmp-reverse.c b/gdb/testsuite/gdb.reverse/singlejmp-reverse.c
new file mode 100644
index 0000000..d275727
--- /dev/null
+++ b/gdb/testsuite/gdb.reverse/singlejmp-reverse.c
@@ -0,0 +1,39 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2012 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/>.  */
+
+volatile int v;
+
+static __attribute__ ((noinline, noclone)) void
+g (void)
+{
+  v = 2;
+}
+
+static __attribute__ ((noinline, noclone)) void
+f (void)
+{
+  g ();
+}
+
+int
+main (void)
+{
+  v = 1;
+  f ();
+  v = 3;
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.reverse/singlejmp-reverse.exp b/gdb/testsuite/gdb.reverse/singlejmp-reverse.exp
new file mode 100644
index 0000000..4fb4d59
--- /dev/null
+++ b/gdb/testsuite/gdb.reverse/singlejmp-reverse.exp
@@ -0,0 +1,50 @@
+# Copyright (C) 2012 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/>.
+
+if ![supports_reverse] {
+    return
+}
+
+set opts {}
+standard_testfile .S
+
+if [info exists COMPILE] {
+    # make check RUNTESTFLAGS="gdb.reverse/singlejmp-reverse.exp COMPILE=1"
+    standard_testfile
+    lappend opts debug optimize=-O2
+} elseif { ![istarget x86_64-*-* ] || ![is_lp64_target] } {
+    verbose "Skipping ${testfile}."
+    return
+}
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile} $opts] } {
+    return -1
+}
+
+if ![runto_main] {
+    return -1
+}
+
+if [supports_process_record] {
+    gdb_test_no_output "record"
+}
+
+gdb_test "next" {f \(\);} "next to f"
+gdb_test "next" {v = 3;} "next to v = 3"
+
+# FAIL was:
+# No more reverse-execution history.
+# v = 1;
+gdb_test "reverse-next" {f \(\);}


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