On Thu, Nov 10, 2016 at 06:17:57PM -0600, Segher Boessenkool wrote:
> On Fri, Nov 11, 2016 at 12:47:02AM +0100, Dominik Vogt wrote:
> > On Thu, Nov 03, 2016 at 11:40:44AM +0100, Dominik Vogt wrote:
> > > The attached patch fixes the stack layout problems on AIX and
> > > Power as described here:
> > >
> > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77359
> > >
> > > The patch has been bootstrapped on AIX (32 Bit) and bootstrappend
> > > and regression tested on Power (biarch). It needs more testing
> > > that I cannot do with the hardware available to me.
> > >
> > > If the patch is good, this one can be re-applied:
> > >
> > > https://gcc.gnu.org/ml/gcc-patches/2016-07/msg01730.html
> > > https://gcc.gnu.org/ml/gcc-patches/2016-08/msg01616.html
> >
> > So, is this patch in order to be committed? (Assuming that a
> > followup patch will clean up the rs6000.h+aix.h quirks.)
>
> You say it needs more testing -- what testing?
Regression testing on AIX (David has done this in reply to the
original message), possibly also on 32-Bit Power, if that is a
reasonable target.
> (And it needs to be posted to gcc-patches@ of course).
This discussion was originally on gcc-patches, but somehow it got
removed from the recipient list.
> > > + : (cfun->calls_alloca \
> > > + ? RS6000_ALIGN (crtl->outgoing_args_size + RS6000_SAVE_AREA, 16)
> > > \
> > > + : (RS6000_ALIGN (crtl->outgoing_args_size, 16) +
> > > RS6000_SAVE_AREA)))
>
> Maybe you can make the comment explain these last two lines as well... It
> seems to me you want to align STARTING_FRAME_OFFSET if calls_alloca?
Done.
> Also add a comment for the one in rs6000.h?
Done.
> > > + RS6000_ALIGN (crtl->outgoing_args_size + (STACK_POINTER_OFFSET), 16)
>
> You don't need parens around STACK_POINTER_OFFSET.
Done.
New patch attached (added more comments and removed parentheses;
not re-tested). (The first attachment is a diff between the two
patches.)
Ciao
Dominik ^_^ ^_^
--
Dominik Vogt
IBM Germany
--- old/0001-PR77359-Properly-align-local-variables-in-functions-.patch
2016-11-11 09:52:16.535439142 +0100
+++ new/0001-PR77359-Properly-align-local-variables-in-functions-.patch
2016-11-11 09:50:03.715439142 +0100
@@ -1,4 +1,4 @@
-From bd36042fd82e29204d2f10c180b9e7c27281eef2 Mon Sep 17 00:00:00 2001
+From faae30210f584bba92ab96aac479ae8f253e59b7 Mon Sep 17 00:00:00 2001
From: Dominik Vogt <v...@linux.vnet.ibm.com>
Date: Fri, 28 Oct 2016 12:59:55 +0100
Subject: [PATCH 1/2] PR77359: Properly align local variables in functions
@@ -7,16 +7,16 @@
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77359 for a discussion of the
problem and the fix.
---
- gcc/config/rs6000/aix.h | 27 +++++++++++++++++++++++++++
+ gcc/config/rs6000/aix.h | 35 +++++++++++++++++++++++++++++++++++
gcc/config/rs6000/rs6000.c | 9 +++++++--
- gcc/config/rs6000/rs6000.h | 14 ++++++++------
- 3 files changed, 42 insertions(+), 8 deletions(-)
+ gcc/config/rs6000/rs6000.h | 26 ++++++++++++++++++--------
+ 3 files changed, 60 insertions(+), 10 deletions(-)
diff --git a/gcc/config/rs6000/aix.h b/gcc/config/rs6000/aix.h
-index b254236..7773517 100644
+index b254236..f6eb122 100644
--- a/gcc/config/rs6000/aix.h
+++ b/gcc/config/rs6000/aix.h
-@@ -40,6 +40,33 @@
+@@ -40,6 +40,41 @@
#undef STACK_BOUNDARY
#define STACK_BOUNDARY 128
@@ -27,7 +27,12 @@
+
+ On the RS/6000, the frame pointer is the same as the stack pointer,
+ except for dynamic allocations. So we start after the fixed area and
-+ outgoing parameter area. */
++ outgoing parameter area.
++
++ If the function uses dynamic stack space (CALLS_ALLOCA is set), that
++ space needs to be aligned to STACK_BOUNDARY, i.e. the sum of the
++ sizes of the fixed area and the parameter area must be a multiple of
++ STACK_BOUNDARY. */
+
+#undef STARTING_FRAME_OFFSET
+#define STARTING_FRAME_OFFSET \
@@ -42,10 +47,13 @@
+
+ The default value for this macro is `STACK_POINTER_OFFSET' plus the
+ length of the outgoing arguments. The default is correct for most
-+ machines. See `function.c' for details. */
++ machines. See `function.c' for details.
++
++ This value must be a multiple of STACK_BOUNDARY (hard coded in
++ `emit-rtl.c'). */
+#undef STACK_DYNAMIC_OFFSET
+#define STACK_DYNAMIC_OFFSET(FUNDECL) \
-+ RS6000_ALIGN (crtl->outgoing_args_size + (STACK_POINTER_OFFSET), 16)
++ RS6000_ALIGN (crtl->outgoing_args_size + STACK_POINTER_OFFSET, 16)
+
#undef TARGET_IEEEQUAD
#define TARGET_IEEEQUAD 0
@@ -71,10 +79,21 @@
info->vars_size
+= RS6000_ALIGN (info->fixed_size + info->vars_size + info->parm_size,
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
-index 4b83abd..c11dc1b 100644
+index 4b83abd..afda416 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
-@@ -1728,9 +1728,12 @@ extern enum reg_class
rs6000_constraints[RS6000_CONSTRAINT_MAX];
+@@ -1723,25 +1723,35 @@ extern enum reg_class
rs6000_constraints[RS6000_CONSTRAINT_MAX];
+
+ On the RS/6000, the frame pointer is the same as the stack pointer,
+ except for dynamic allocations. So we start after the fixed area and
+- outgoing parameter area. */
++ outgoing parameter area.
++
++ If the function uses dynamic stack space (CALLS_ALLOCA is set), that
++ space needs to be aligned to STACK_BOUNDARY, i.e. the sum of the
++ sizes of the fixed area and the parameter area must be a multiple of
++ STACK_BOUNDARY. */
+
#define STARTING_FRAME_OFFSET \
(FRAME_GROWS_DOWNWARD
\
? 0
\
@@ -90,14 +109,19 @@
/* Offset from the stack pointer register to an item dynamically
allocated on the stack, e.g., by `alloca'.
-@@ -1739,9 +1742,8 @@ extern enum reg_class
rs6000_constraints[RS6000_CONSTRAINT_MAX];
+
+ The default value for this macro is `STACK_POINTER_OFFSET' plus the
length of the outgoing arguments. The default is correct for most
- machines. See `function.c' for details. */
+- machines. See `function.c' for details. */
++ machines. See `function.c' for details.
++
++ This value must be a multiple of STACK_BOUNDARY (hard coded in
++ `emit-rtl.c'). */
#define STACK_DYNAMIC_OFFSET(FUNDECL) \
- (RS6000_ALIGN (crtl->outgoing_args_size, \
- (TARGET_ALTIVEC || TARGET_VSX) ? 16 : 8) \
- + (STACK_POINTER_OFFSET))
-+ RS6000_ALIGN (crtl->outgoing_args_size + (STACK_POINTER_OFFSET), \
++ RS6000_ALIGN (crtl->outgoing_args_size + STACK_POINTER_OFFSET, \
+ (TARGET_ALTIVEC || TARGET_VSX) ? 16 : 8)
/* If we generate an insn to push BYTES bytes,
gcc/ChangeLog
* config/rs6000/rs6000.c (rs6000_stack_info): Properly align local
variables in functions calling alloca.
* config/rs6000/rs6000.h (STARTING_FRAME_OFFSET, STACK_DYNAMIC_OFFSET):
Likewise.
* config/rs6000/aix.h (STARTING_FRAME_OFFSET, STACK_DYNAMIC_OFFSET):
Copy AIX specific versions of the rs6000.h macros to aix.h.
>From faae30210f584bba92ab96aac479ae8f253e59b7 Mon Sep 17 00:00:00 2001
From: Dominik Vogt <v...@linux.vnet.ibm.com>
Date: Fri, 28 Oct 2016 12:59:55 +0100
Subject: [PATCH] PR77359: Properly align local variables in functions
calling alloca.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77359 for a discussion of the
problem and the fix.
---
gcc/config/rs6000/aix.h | 35 +++++++++++++++++++++++++++++++++++
gcc/config/rs6000/rs6000.c | 9 +++++++--
gcc/config/rs6000/rs6000.h | 26 ++++++++++++++++++--------
3 files changed, 60 insertions(+), 10 deletions(-)
diff --git a/gcc/config/rs6000/aix.h b/gcc/config/rs6000/aix.h
index b254236..f6eb122 100644
--- a/gcc/config/rs6000/aix.h
+++ b/gcc/config/rs6000/aix.h
@@ -40,6 +40,41 @@
#undef STACK_BOUNDARY
#define STACK_BOUNDARY 128
+/* Offset within stack frame to start allocating local variables at.
+ If FRAME_GROWS_DOWNWARD, this is the offset to the END of the
+ first local allocated. Otherwise, it is the offset to the BEGINNING
+ of the first local allocated.
+
+ On the RS/6000, the frame pointer is the same as the stack pointer,
+ except for dynamic allocations. So we start after the fixed area and
+ outgoing parameter area.
+
+ If the function uses dynamic stack space (CALLS_ALLOCA is set), that
+ space needs to be aligned to STACK_BOUNDARY, i.e. the sum of the
+ sizes of the fixed area and the parameter area must be a multiple of
+ STACK_BOUNDARY. */
+
+#undef STARTING_FRAME_OFFSET
+#define STARTING_FRAME_OFFSET \
+ (FRAME_GROWS_DOWNWARD
\
+ ? 0 \
+ : (cfun->calls_alloca \
+ ? RS6000_ALIGN (crtl->outgoing_args_size + RS6000_SAVE_AREA, 16) \
+ : (RS6000_ALIGN (crtl->outgoing_args_size, 16) + RS6000_SAVE_AREA)))
+
+/* Offset from the stack pointer register to an item dynamically
+ allocated on the stack, e.g., by `alloca'.
+
+ The default value for this macro is `STACK_POINTER_OFFSET' plus the
+ length of the outgoing arguments. The default is correct for most
+ machines. See `function.c' for details.
+
+ This value must be a multiple of STACK_BOUNDARY (hard coded in
+ `emit-rtl.c'). */
+#undef STACK_DYNAMIC_OFFSET
+#define STACK_DYNAMIC_OFFSET(FUNDECL) \
+ RS6000_ALIGN (crtl->outgoing_args_size + STACK_POINTER_OFFSET, 16)
+
#undef TARGET_IEEEQUAD
#define TARGET_IEEEQUAD 0
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index f9e4739..02ed9c1 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -26004,8 +26004,13 @@ rs6000_stack_info (void)
info->reg_size = reg_size;
info->fixed_size = RS6000_SAVE_AREA;
info->vars_size = RS6000_ALIGN (get_frame_size (), 8);
- info->parm_size = RS6000_ALIGN (crtl->outgoing_args_size,
- TARGET_ALTIVEC ? 16 : 8);
+ if (cfun->calls_alloca)
+ info->parm_size =
+ RS6000_ALIGN (crtl->outgoing_args_size + info->fixed_size,
+ STACK_BOUNDARY / BITS_PER_UNIT) - info->fixed_size;
+ else
+ info->parm_size = RS6000_ALIGN (crtl->outgoing_args_size,
+ TARGET_ALTIVEC ? 16 : 8);
if (FRAME_GROWS_DOWNWARD)
info->vars_size
+= RS6000_ALIGN (info->fixed_size + info->vars_size + info->parm_size,
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 4b83abd..afda416 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -1723,25 +1723,35 @@ extern enum reg_class
rs6000_constraints[RS6000_CONSTRAINT_MAX];
On the RS/6000, the frame pointer is the same as the stack pointer,
except for dynamic allocations. So we start after the fixed area and
- outgoing parameter area. */
+ outgoing parameter area.
+
+ If the function uses dynamic stack space (CALLS_ALLOCA is set), that
+ space needs to be aligned to STACK_BOUNDARY, i.e. the sum of the
+ sizes of the fixed area and the parameter area must be a multiple of
+ STACK_BOUNDARY. */
#define STARTING_FRAME_OFFSET \
(FRAME_GROWS_DOWNWARD
\
? 0 \
- : (RS6000_ALIGN (crtl->outgoing_args_size, \
- (TARGET_ALTIVEC || TARGET_VSX) ? 16 : 8) \
- + RS6000_SAVE_AREA))
+ : (cfun->calls_alloca \
+ ? (RS6000_ALIGN (crtl->outgoing_args_size + RS6000_SAVE_AREA, \
+ (TARGET_ALTIVEC || TARGET_VSX) ? 16 : 8 )) \
+ : (RS6000_ALIGN (crtl->outgoing_args_size, \
+ (TARGET_ALTIVEC || TARGET_VSX) ? 16 : 8) \
+ + RS6000_SAVE_AREA)))
/* Offset from the stack pointer register to an item dynamically
allocated on the stack, e.g., by `alloca'.
The default value for this macro is `STACK_POINTER_OFFSET' plus the
length of the outgoing arguments. The default is correct for most
- machines. See `function.c' for details. */
+ machines. See `function.c' for details.
+
+ This value must be a multiple of STACK_BOUNDARY (hard coded in
+ `emit-rtl.c'). */
#define STACK_DYNAMIC_OFFSET(FUNDECL) \
- (RS6000_ALIGN (crtl->outgoing_args_size, \
- (TARGET_ALTIVEC || TARGET_VSX) ? 16 : 8) \
- + (STACK_POINTER_OFFSET))
+ RS6000_ALIGN (crtl->outgoing_args_size + STACK_POINTER_OFFSET, \
+ (TARGET_ALTIVEC || TARGET_VSX) ? 16 : 8)
/* If we generate an insn to push BYTES bytes,
this says how many the stack pointer really advances by.
--
2.3.0
