On Wed, Sep 16, 2020 at 4:47 AM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Wed, Sep 16, 2020 at 12:34:50PM +0100, Richard Sandiford wrote:
> > Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> > > On Mon, Sep 14, 2020 at 08:57:18AM -0700, H.J. Lu via Gcc-patches wrote:
> > >> Something like this for GCC 8 and 9.
> > >
> > > Guess my preference would be to do this everywhere and then let's discuss
> > > if
> > > we change the warning into error there or keep it being deprecated.
> >
> > Agreed FWIW. On turning it into an error: I think it might be better
> > to wait a bit longer if we can.
>
> Ok. The patch is ok for trunk and affected release branches after a week.
>
I cherry-picked it to GCC 9 and 10 branches. GCC 8 needs some
changes. I am enclosing the backported patch for GCC 8. I will check
it in if there are no regressions on Linux/x86-64.
Thanks.
H.J.
From 97c34eb5f57bb1d37f3feddefefa5f553bcea9fc Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.to...@gmail.com>
Date: Mon, 14 Sep 2020 08:52:27 -0700
Subject: [PATCH] rtl_data: Add sp_is_clobbered_by_asm
Add sp_is_clobbered_by_asm to rtl_data to inform backends that the stack
pointer is clobbered by asm statement.
gcc/
PR target/97032
* cfgexpand.c (expand_asm_stmt): Set sp_is_clobbered_by_asm to
true if the stack pointer is clobbered by asm statement.
* emit-rtl.h (rtl_data): Add sp_is_clobbered_by_asm.
* config/i386/i386.c (ix86_get_drap_rtx): Set need_drap to true
if the stack pointer is clobbered by asm statement.
gcc/testsuite/
PR target/97032
* gcc.target/i386/pr97032.c: New test.
(cherry picked from commit 453a20c65722719b9e2d84339f215e7ec87692dc)
---
gcc/cfgexpand.c | 3 +++
gcc/config/i386/i386.c | 6 ++++--
gcc/emit-rtl.h | 3 +++
gcc/testsuite/gcc.target/i386/pr97032.c | 22 ++++++++++++++++++++++
4 files changed, 32 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr97032.c
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 18565bf1dab..dcf491954f1 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -2972,6 +2972,9 @@ expand_asm_stmt (gasm *stmt)
regname);
return;
}
+ /* Clobbering the stack pointer register. */
+ else if (reg == (int) STACK_POINTER_REGNUM)
+ crtl->sp_is_clobbered_by_asm = true;
SET_HARD_REG_BIT (clobbered_regs, reg);
rtx x = gen_rtx_REG (reg_raw_mode[reg], reg);
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index f3c722b51e9..ce20bc2ab4e 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -12528,10 +12528,12 @@ ix86_update_stack_boundary (void)
static rtx
ix86_get_drap_rtx (void)
{
- /* We must use DRAP if there are outgoing arguments on stack and
+ /* We must use DRAP if there are outgoing arguments on stack or
+ the stack pointer register is clobbered by asm statment and
ACCUMULATE_OUTGOING_ARGS is false. */
if (ix86_force_drap
- || (cfun->machine->outgoing_args_on_stack
+ || ((cfun->machine->outgoing_args_on_stack
+ || crtl->sp_is_clobbered_by_asm)
&& !ACCUMULATE_OUTGOING_ARGS))
crtl->need_drap = true;
diff --git a/gcc/emit-rtl.h b/gcc/emit-rtl.h
index 4e7bd1ec26d..55dc3e84e9c 100644
--- a/gcc/emit-rtl.h
+++ b/gcc/emit-rtl.h
@@ -265,6 +265,9 @@ struct GTY(()) rtl_data {
pass_stack_ptr_mod has run. */
bool sp_is_unchanging;
+ /* True if the stack pointer is clobbered by asm statement. */
+ bool sp_is_clobbered_by_asm;
+
/* Nonzero if function being compiled doesn't contain any calls
(ignoring the prologue and epilogue). This is set prior to
register allocation in IRA and is valid for the remaining
diff --git a/gcc/testsuite/gcc.target/i386/pr97032.c b/gcc/testsuite/gcc.target/i386/pr97032.c
new file mode 100644
index 00000000000..b9ef2ad0c05
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr97032.c
@@ -0,0 +1,22 @@
+/* { dg-do compile { target { ia32 && fstack_protector } } } */
+/* { dg-options "-O2 -mincoming-stack-boundary=2 -fstack-protector-all" } */
+
+#include <stdarg.h>
+
+extern int *__errno_location (void);
+
+long
+sys_socketcall (int op, ...)
+{
+ long int res;
+ va_list ap;
+ va_start (ap, op);
+ asm volatile ("push %%ebx; movl %2, %%ebx; int $0x80; pop %%ebx"
+ : "=a" (res) : "0" (102), "ri" (16), "c" (ap) : "memory", "esp");
+ if (__builtin_expect (res > 4294963200UL, 0))
+ *__errno_location () = -res;
+ va_end (ap);
+ return res;
+}
+
+/* { dg-final { scan-assembler "call\[ \t\]*_?__errno_location" } } */
--
2.26.2
