gdb and binutils branch master updated. 808f7ab1fc88da40007c17a20e49928359f27491

[qiyao at sourceware dot org]

This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "gdb and binutils".

The branch, master has been updated
       via  808f7ab1fc88da40007c17a20e49928359f27491 (commit)
       via  540314bdd87c7478d21b44dd4856d937bcc1479b (commit)
       via  1db01f22f58cc01768dc921a7443a1bad4e48eb5 (commit)
      from  3116063bd617de56fbc3bad046a692b1fb363a9d (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=808f7ab1fc88da40007c17a20e49928359f27491

commit 808f7ab1fc88da40007c17a20e49928359f27491
Author: Yao Qi <yao@codesourcery.com>
Date:   Wed Jul 2 15:16:26 2014 +0800

    Stop prologue analysis when past the epilogue
    
    We see a fail in gdb.trace/entry-values.exp on armv4t thumb,
    
    bt^M
     #0  0x000086fc in foo (i=0, i@entry=<optimized out>, j=2, j@entry=<optimized out>)^M
     #1  0x00000002 in ?? ()^M
    Backtrace stopped: previous frame identical to this frame (corrupt stack?)^M
    (gdb) FAIL: gdb.trace/entry-values.exp: bt (1) (pattern 1)
    
    The fail is caused by incorrect prologue analysis, which can be illustrated by
    setting a breakpoint on function foo,
    
    (gdb) disassemble foo
    Dump of assembler code for function foo:
       0x000086e8 <+0>:	push	{r7, lr}
       0x000086ea <+2>:	sub	sp, #8
       0x000086ec <+4>:	add	r7, sp, #0
       0x000086ee <+6>:	str	r0, [r7, #4]
       0x000086f0 <+8>:	str	r1, [r7, #0]
       0x000086f2 <+10>:	movs	r3, #0
       0x000086f4 <+12>:	adds	r0, r3, #0
       0x000086f6 <+14>:	mov	sp, r7
       0x000086f8 <+16>:	add	sp, #8
       0x000086fa <+18>:	pop	{r7}
       0x000086fc <+20>:	pop	{r1}
       0x000086fe <+22>:	bx	r1
    End of assembler dump.
    (gdb) b foo
    Breakpoint 1 at 0x86fc
    
    As we can see, GDB analyzes the prologue and skip the prologue to the last
    instruction but one.  The breakpoint is set within the epilogue, and GDB
    skips too many instruction for prologue.  This patch teaches GDB to stop
    prologue analysis when goes into the epilogue.  With this patch applied,
    GDB is able to unwind correctly,
    
    (gdb) bt
     #0  0x000086f6 in foo (i=0, i@entry=2, j=2, j@entry=3)
     #1  0x00008718 in bar (i=<optimized out>)
     #2  0x00008758 in main ()
    
    gdb:
    
    2014-07-11  Yao Qi  <yao@codesourcery.com>
    
    	* arm-tdep.c (thumb_analyze_prologue): Break the loop if
    	thumb_instruction_restores_sp return true.

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=540314bdd87c7478d21b44dd4856d937bcc1479b

commit 540314bdd87c7478d21b44dd4856d937bcc1479b
Author: Yao Qi <yao@codesourcery.com>
Date:   Wed Jul 2 14:45:12 2014 +0800

    Match instruction adjusts SP in thumb
    
    This is a refactor patch, that moves matching instructions adjusting
    SP into a new function, thumb_instruction_restores_sp.  The second
    call to thumb_instruction_restores_sp in thumb_in_function_epilogue_p
    is a little different from the original.  The original code matches
    'POP <registers> without PC', but thumb_in_function_epilogue_p matches
    'POP <registers> (with and without PC)'.  However, GDB found one
    instruction about return and is scanning the previous instruction,
    which should be an instruction about return too, so the code change
    doesn't affect the functionality.
    
    gdb:
    
    2014-07-11  Yao Qi  <yao@codesourcery.com>
    
    	* arm-tdep.c (thumb_instruction_restores_sp): New function.
    	(thumb_in_function_epilogue_p): Call
    	thumb_instruction_restores_sp.

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1db01f22f58cc01768dc921a7443a1bad4e48eb5

commit 1db01f22f58cc01768dc921a7443a1bad4e48eb5
Author: Yao Qi <yao@codesourcery.com>
Date:   Tue Jul 1 15:36:44 2014 +0800

    Restrict matching add/sub sp, #imm
    
    Currently, GDB matches both add/sub sp, #imm in prologue and epilogue,
    which is not very precise.  On the instruction level, the immediate
    number in both instruction can't be negative, so 'sub sp, #imm' only
    appears in prologue while 'add sp, #imm' only appears in epilogue.
    Note that on assembly level, we can write 'add sp, -8', but gas will
    translate to 'sub sp, 8' instruction.
    
    This patch is to only match 'sub sp, #imm' in prologue and match
    'add sp, #immm' in epilogue.  It paves the way for the following
    patch.
    
    gdb:
    
    2014-07-11  Yao Qi  <yao@codesourcery.com>
    
    	* arm-tdep.c (thumb_analyze_prologue): Don't match instruction
    	'add sp, #imm'.
    	(thumb_in_function_epilogue_p): Don't match 'sub sp, #imm'.

-----------------------------------------------------------------------

Summary of changes:
 gdb/ChangeLog  |   17 +++++++++++++++++
 gdb/arm-tdep.c |   41 ++++++++++++++++++++++-------------------
 2 files changed, 39 insertions(+), 19 deletions(-)


hooks/post-receive
-- 
gdb and binutils