diff mbox

[GCC/ARM] Fix PR77904: callee-saved register trashed when clobbering sp

Message ID 7a70eca3-3442-2553-2434-08b5e00879a3@foss.arm.com
State New
Headers show

Commit Message

Thomas Preudhomme Nov. 30, 2016, 10:42 a.m. UTC
Hi,

Is this ok to backport to gcc-5-branch and gcc-6-branch? Patch applies cleanly 
(patches attached for reference).


2016-11-30 Thomas Preud'homme <thomas.preudhomme@arm.com>

     Backport from mainline
     2016-11-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>

     gcc/
     PR target/77904
     * config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer
     in save register mask if it is needed.

     gcc/testsuite/
     PR target/77904
     * gcc.target/arm/pr77904.c: New test.


Best regards,

Thomas


On 22/11/16 10:45, Thomas Preudhomme wrote:
> On 17/11/16 09:11, Kyrill Tkachov wrote:
>>
>> On 17/11/16 08:56, Thomas Preudhomme wrote:
>>> On 16/11/16 10:30, Kyrill Tkachov wrote:
>>>> Hi Thomas,
>>>>
>>>> On 03/11/16 16:52, Thomas Preudhomme wrote:
>>>>> Hi,
>>>>>
>>>>> When using a callee-saved register to save the frame pointer the Thumb-1
>>>>> prologue fails to save the callee-saved register before that. For ARM and
>>>>> Thumb-2 targets the frame pointer is handled as a special case but nothing is
>>>>> done for Thumb-1 targets. This patch adds the same logic for Thumb-1 targets.
>>>>>
>>>>> ChangeLog entries are as follow:
>>>>>
>>>>> *** gcc/ChangeLog ***
>>>>>
>>>>> 2016-11-02  Thomas Preud'homme <thomas.preudhomme@arm.com>
>>>>>
>>>>>         PR target/77904
>>>>>         * config/arm/arm.c (thumb1_compute_save_reg_mask): mark frame pointer
>>>>>         in save register mask if it is needed.
>>>>>
>>>>
>>>> s/mark/Mark/
>>>>
>>>>>
>>>>> *** gcc/testsuite/ChangeLog ***
>>>>>
>>>>> 2016-11-02  Thomas Preud'homme <thomas.preudhomme@arm.com>
>>>>>
>>>>>         PR target/77904
>>>>>         * gcc.target/arm/pr77904.c: New test.
>>>>>
>>>>>
>>>>> Testing: Testsuite shows no regression when run with arm-none-eabi GCC
>>>>> cross-compiler for Cortex-M0 target.
>>>>>
>>>>> Is this ok for trunk?
>>>>>
>>>>
>>>> I'd ask for a bootstrap, but this code is Thumb-1 only so it wouldn't affect
>>>> anything.
>>>
>>> I can bootstrap for armv4t with --with-mode=thumb which would at least
>>> exercise the path. I'll try such a bootstrap on qemu.
>>>
>>
>> If you can get it to work, then yes please.
>
> Bootstrap came back clean so I've committed the patch (r242693). Thanks!
>
> Best regards,
>
> Thomas

Comments

Thomas Preudhomme Nov. 30, 2016, 10:44 a.m. UTC | #1
Sorry, the bug cannot be reproduced on gcc-5-branch so it's probably better to 
only do a backport to gcc-6-branch.

Ok for a backport to gcc-6-branch?

Best regards,

Thomas

On 30/11/16 10:42, Thomas Preudhomme wrote:
> Hi,
>
> Is this ok to backport to gcc-5-branch and gcc-6-branch? Patch applies cleanly
> (patches attached for reference).
>
>
> 2016-11-30 Thomas Preud'homme <thomas.preudhomme@arm.com>
>
>     Backport from mainline
>     2016-11-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>
>     gcc/
>     PR target/77904
>     * config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer
>     in save register mask if it is needed.
>
>     gcc/testsuite/
>     PR target/77904
>     * gcc.target/arm/pr77904.c: New test.
>
>
> Best regards,
>
> Thomas
>
>
> On 22/11/16 10:45, Thomas Preudhomme wrote:
>> On 17/11/16 09:11, Kyrill Tkachov wrote:
>>>
>>> On 17/11/16 08:56, Thomas Preudhomme wrote:
>>>> On 16/11/16 10:30, Kyrill Tkachov wrote:
>>>>> Hi Thomas,
>>>>>
>>>>> On 03/11/16 16:52, Thomas Preudhomme wrote:
>>>>>> Hi,
>>>>>>
>>>>>> When using a callee-saved register to save the frame pointer the Thumb-1
>>>>>> prologue fails to save the callee-saved register before that. For ARM and
>>>>>> Thumb-2 targets the frame pointer is handled as a special case but nothing is
>>>>>> done for Thumb-1 targets. This patch adds the same logic for Thumb-1 targets.
>>>>>>
>>>>>> ChangeLog entries are as follow:
>>>>>>
>>>>>> *** gcc/ChangeLog ***
>>>>>>
>>>>>> 2016-11-02  Thomas Preud'homme <thomas.preudhomme@arm.com>
>>>>>>
>>>>>>         PR target/77904
>>>>>>         * config/arm/arm.c (thumb1_compute_save_reg_mask): mark frame pointer
>>>>>>         in save register mask if it is needed.
>>>>>>
>>>>>
>>>>> s/mark/Mark/
>>>>>
>>>>>>
>>>>>> *** gcc/testsuite/ChangeLog ***
>>>>>>
>>>>>> 2016-11-02  Thomas Preud'homme <thomas.preudhomme@arm.com>
>>>>>>
>>>>>>         PR target/77904
>>>>>>         * gcc.target/arm/pr77904.c: New test.
>>>>>>
>>>>>>
>>>>>> Testing: Testsuite shows no regression when run with arm-none-eabi GCC
>>>>>> cross-compiler for Cortex-M0 target.
>>>>>>
>>>>>> Is this ok for trunk?
>>>>>>
>>>>>
>>>>> I'd ask for a bootstrap, but this code is Thumb-1 only so it wouldn't affect
>>>>> anything.
>>>>
>>>> I can bootstrap for armv4t with --with-mode=thumb which would at least
>>>> exercise the path. I'll try such a bootstrap on qemu.
>>>>
>>>
>>> If you can get it to work, then yes please.
>>
>> Bootstrap came back clean so I've committed the patch (r242693). Thanks!
>>
>> Best regards,
>>
>> Thomas
diff mbox

Patch

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 83cb13d1195beb19d6301f5c83a7eb544a91d877..ae479a43fe8514f2eacb7d56f89916b48f720768 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -19390,6 +19390,10 @@  thumb1_compute_save_reg_mask (void)
     if (df_regs_ever_live_p (reg) && callee_saved_reg_p (reg))
       mask |= 1 << reg;
 
+  /* Handle the frame pointer as a special case.  */
+  if (frame_pointer_needed)
+    mask |= 1 << HARD_FRAME_POINTER_REGNUM;
+
   if (flag_pic
       && !TARGET_SINGLE_PIC_BASE
       && arm_pic_register != INVALID_REGNUM
diff --git a/gcc/testsuite/gcc.target/arm/pr77904.c b/gcc/testsuite/gcc.target/arm/pr77904.c
new file mode 100644
index 0000000000000000000000000000000000000000..76728c07e73350ce44160cabff3dd2fa7a6ef021
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr77904.c
@@ -0,0 +1,45 @@ 
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+__attribute__ ((noinline, noclone)) void
+clobber_sp (void)
+{
+  __asm volatile ("" : : : "sp");
+}
+
+int
+main (void)
+{
+  int ret;
+
+  __asm volatile ("mov\tr4, #0xf4\n\t"
+		  "mov\tr5, #0xf5\n\t"
+		  "mov\tr6, #0xf6\n\t"
+		  "mov\tr7, #0xf7\n\t"
+		  "mov\tr0, #0xf8\n\t"
+		  "mov\tr8, r0\n\t"
+		  "mov\tr0, #0xfa\n\t"
+		  "mov\tr10, r0"
+		  : : : "r0", "r4", "r5", "r6", "r7", "r8", "r10");
+  clobber_sp ();
+
+  __asm volatile ("cmp\tr4, #0xf4\n\t"
+		  "bne\tfail\n\t"
+		  "cmp\tr5, #0xf5\n\t"
+		  "bne\tfail\n\t"
+		  "cmp\tr6, #0xf6\n\t"
+		  "bne\tfail\n\t"
+		  "cmp\tr7, #0xf7\n\t"
+		  "bne\tfail\n\t"
+		  "mov\tr0, r8\n\t"
+		  "cmp\tr0, #0xf8\n\t"
+		  "bne\tfail\n\t"
+		  "mov\tr0, r10\n\t"
+		  "cmp\tr0, #0xfa\n\t"
+		  "bne\tfail\n\t"
+		  "mov\t%0, #1\n"
+		  "fail:\n\t"
+		  "sub\tr0, #1"
+		  : "=r" (ret) : :);
+  return ret;
+}