diff mbox series

x86: Insert ENDBR if function will be called indirectly

Message ID 20200331151134.483137-1-hjl.tools@gmail.com
State New
Headers show
Series x86: Insert ENDBR if function will be called indirectly | expand

Commit Message

Li, Pan2 via Gcc-patches March 31, 2020, 3:11 p.m. UTC 
Since constant_call_address_operand has

;; Test for a pc-relative call operand
(define_predicate "constant_call_address_operand"
  (match_code "symbol_ref")
{
  if (ix86_cmodel == CM_LARGE || ix86_cmodel == CM_LARGE_PIC
      || flag_force_indirect_call)
    return false;
  if (TARGET_DLLIMPORT_DECL_ATTRIBUTES && SYMBOL_REF_DLLIMPORT_P (op))
    return false;
  return true;
})

even if cgraph_node::get (cfun->decl)->only_called_directly_p () returns
false, the fuction may still be called indirectly.  Copy the logic from
constant_call_address_operand to rest_of_insert_endbranch to insert ENDBR
at function entry if function will be called indirectly.

gcc/

	PR target/94417
	* config/i386/i386-features.c (rest_of_insert_endbranch): Insert
	ENDBR at function entry if function will be called indirectly.

gcc/testsuite/

	PR target/94417
	* gcc.target/i386/pr94417-1.c: New test.
	* gcc.target/i386/pr94417-2.c: Likewise.
	* gcc.target/i386/pr94417-3.c: Likewise.
---
 gcc/config/i386/i386-features.c           |  7 ++++++-
 gcc/testsuite/gcc.target/i386/pr94417-1.c | 20 ++++++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr94417-2.c | 21 +++++++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr94417-3.c | 19 +++++++++++++++++++
 4 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr94417-1.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr94417-2.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr94417-3.c

Comments

Li, Pan2 via Gcc-patches April 8, 2020, 4:16 p.m. UTC | #1 
On Tue, 2020-03-31 at 08:11 -0700, H.J. Lu via Gcc-patches wrote:
> Since constant_call_address_operand has
> 
> ;; Test for a pc-relative call operand
> (define_predicate "constant_call_address_operand"
>   (match_code "symbol_ref")
> {
>   if (ix86_cmodel == CM_LARGE || ix86_cmodel == CM_LARGE_PIC
>       || flag_force_indirect_call)
>     return false;
>   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES && SYMBOL_REF_DLLIMPORT_P (op))
>     return false;
>   return true;
> })
> 
> even if cgraph_node::get (cfun->decl)->only_called_directly_p () returns
> false, the fuction may still be called indirectly.  Copy the logic from
> constant_call_address_operand to rest_of_insert_endbranch to insert ENDBR
> at function entry if function will be called indirectly.
> 
> gcc/
> 
> 	PR target/94417
> 	* config/i386/i386-features.c (rest_of_insert_endbranch): Insert
> 	ENDBR at function entry if function will be called indirectly.
Can you just call constant_call_address_operand rather than copying its contents?

jeff
>
Li, Pan2 via Gcc-patches April 8, 2020, 4:23 p.m. UTC | #2 
On Wed, Apr 8, 2020 at 9:16 AM Jeff Law <law@redhat.com> wrote:
>
> On Tue, 2020-03-31 at 08:11 -0700, H.J. Lu via Gcc-patches wrote:
> > Since constant_call_address_operand has
> >
> > ;; Test for a pc-relative call operand
> > (define_predicate "constant_call_address_operand"
> >   (match_code "symbol_ref")
> > {
> >   if (ix86_cmodel == CM_LARGE || ix86_cmodel == CM_LARGE_PIC
> >       || flag_force_indirect_call)
> >     return false;
> >   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES && SYMBOL_REF_DLLIMPORT_P (op))
> >     return false;
> >   return true;
> > })
> >
> > even if cgraph_node::get (cfun->decl)->only_called_directly_p () returns
> > false, the fuction may still be called indirectly.  Copy the logic from
> > constant_call_address_operand to rest_of_insert_endbranch to insert ENDBR
> > at function entry if function will be called indirectly.
> >
> > gcc/
> >
> >       PR target/94417
> >       * config/i386/i386-features.c (rest_of_insert_endbranch): Insert
> >       ENDBR at function entry if function will be called indirectly.
> Can you just call constant_call_address_operand rather than copying its contents?

I wish I could.  constant_call_address_operand uses SYMBOL_REF_DLLIMPORT_P (op)
But I need to use DECL_DLLIMPORT_P (cfun->decl)).
Li, Pan2 via Gcc-patches April 8, 2020, 4:41 p.m. UTC | #3 
On Wed, 2020-04-08 at 09:23 -0700, H.J. Lu wrote:
> On Wed, Apr 8, 2020 at 9:16 AM Jeff Law <law@redhat.com> wrote:
> > On Tue, 2020-03-31 at 08:11 -0700, H.J. Lu via Gcc-patches wrote:
> > > Since constant_call_address_operand has
> > > 
> > > ;; Test for a pc-relative call operand
> > > (define_predicate "constant_call_address_operand"
> > >   (match_code "symbol_ref")
> > > {
> > >   if (ix86_cmodel == CM_LARGE || ix86_cmodel == CM_LARGE_PIC
> > >       || flag_force_indirect_call)
> > >     return false;
> > >   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES && SYMBOL_REF_DLLIMPORT_P (op))
> > >     return false;
> > >   return true;
> > > })
> > > 
> > > even if cgraph_node::get (cfun->decl)->only_called_directly_p () returns
> > > false, the fuction may still be called indirectly.  Copy the logic from
> > > constant_call_address_operand to rest_of_insert_endbranch to insert ENDBR
> > > at function entry if function will be called indirectly.
> > > 
> > > gcc/
> > > 
> > >       PR target/94417
> > >       * config/i386/i386-features.c (rest_of_insert_endbranch): Insert
> > >       ENDBR at function entry if function will be called indirectly.
> > Can you just call constant_call_address_operand rather than copying its
> > contents?
> 
> I wish I could.  constant_call_address_operand uses SYMBOL_REF_DLLIMPORT_P (op)
> But I need to use DECL_DLLIMPORT_P (cfun->decl)).
Sigh.  In that case I guess the patch is OK as-is.  

jeff
>
H.J. Lu April 17, 2020, 3:18 p.m. UTC | #4 
On Wed, Apr 8, 2020 at 9:41 AM Jeff Law <law@redhat.com> wrote:
>
> On Wed, 2020-04-08 at 09:23 -0700, H.J. Lu wrote:
> > On Wed, Apr 8, 2020 at 9:16 AM Jeff Law <law@redhat.com> wrote:
> > > On Tue, 2020-03-31 at 08:11 -0700, H.J. Lu via Gcc-patches wrote:
> > > > Since constant_call_address_operand has
> > > >
> > > > ;; Test for a pc-relative call operand
> > > > (define_predicate "constant_call_address_operand"
> > > >   (match_code "symbol_ref")
> > > > {
> > > >   if (ix86_cmodel == CM_LARGE || ix86_cmodel == CM_LARGE_PIC
> > > >       || flag_force_indirect_call)
> > > >     return false;
> > > >   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES && SYMBOL_REF_DLLIMPORT_P (op))
> > > >     return false;
> > > >   return true;
> > > > })
> > > >
> > > > even if cgraph_node::get (cfun->decl)->only_called_directly_p () returns
> > > > false, the fuction may still be called indirectly.  Copy the logic from
> > > > constant_call_address_operand to rest_of_insert_endbranch to insert ENDBR
> > > > at function entry if function will be called indirectly.
> > > >
> > > > gcc/
> > > >
> > > >       PR target/94417
> > > >       * config/i386/i386-features.c (rest_of_insert_endbranch): Insert
> > > >       ENDBR at function entry if function will be called indirectly.
> > > Can you just call constant_call_address_operand rather than copying its
> > > contents?
> >
> > I wish I could.  constant_call_address_operand uses SYMBOL_REF_DLLIMPORT_P (op)
> > But I need to use DECL_DLLIMPORT_P (cfun->decl)).
> Sigh.  In that case I guess the patch is OK as-is.
>

I'd like to backport this wrong code fix to GCC 9/8 branches.
Is it OK for GCC 9/8 branches?

Thanks.
Li, Pan2 via Gcc-patches April 17, 2020, 10:15 p.m. UTC | #5 
On Fri, 2020-04-17 at 08:18 -0700, H.J. Lu wrote:
> On Wed, Apr 8, 2020 at 9:41 AM Jeff Law <law@redhat.com> wrote:
> > On Wed, 2020-04-08 at 09:23 -0700, H.J. Lu wrote:
> > > On Wed, Apr 8, 2020 at 9:16 AM Jeff Law <law@redhat.com> wrote:
> > > > On Tue, 2020-03-31 at 08:11 -0700, H.J. Lu via Gcc-patches wrote:
> > > > > Since constant_call_address_operand has
> > > > > 
> > > > > ;; Test for a pc-relative call operand
> > > > > (define_predicate "constant_call_address_operand"
> > > > >   (match_code "symbol_ref")
> > > > > {
> > > > >   if (ix86_cmodel == CM_LARGE || ix86_cmodel == CM_LARGE_PIC
> > > > >       || flag_force_indirect_call)
> > > > >     return false;
> > > > >   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES && SYMBOL_REF_DLLIMPORT_P (op))
> > > > >     return false;
> > > > >   return true;
> > > > > })
> > > > > 
> > > > > even if cgraph_node::get (cfun->decl)->only_called_directly_p ()
> > > > > returns
> > > > > false, the fuction may still be called indirectly.  Copy the logic from
> > > > > constant_call_address_operand to rest_of_insert_endbranch to insert
> > > > > ENDBR
> > > > > at function entry if function will be called indirectly.
> > > > > 
> > > > > gcc/
> > > > > 
> > > > >       PR target/94417
> > > > >       * config/i386/i386-features.c (rest_of_insert_endbranch): Insert
> > > > >       ENDBR at function entry if function will be called indirectly.
> > > > Can you just call constant_call_address_operand rather than copying its
> > > > contents?
> > > 
> > > I wish I could.  constant_call_address_operand uses SYMBOL_REF_DLLIMPORT_P
> > > (op)
> > > But I need to use DECL_DLLIMPORT_P (cfun->decl)).
> > Sigh.  In that case I guess the patch is OK as-is.
> > 
> 
> I'd like to backport this wrong code fix to GCC 9/8 branches.
> Is it OK for GCC 9/8 branches?
Sure.
jeff
diff mbox series

Patch

diff --git a/gcc/config/i386/i386-features.c b/gcc/config/i386/i386-features.c
index 66b120d21a7..78fb373db6e 100644
--- a/gcc/config/i386/i386-features.c
+++ b/gcc/config/i386/i386-features.c
@@ -1963,7 +1963,12 @@  rest_of_insert_endbranch (void)
       && (!flag_manual_endbr
 	  || lookup_attribute ("cf_check",
 			       DECL_ATTRIBUTES (cfun->decl)))
-      && !cgraph_node::get (cfun->decl)->only_called_directly_p ())
+      && (!cgraph_node::get (cfun->decl)->only_called_directly_p ()
+	  || ix86_cmodel == CM_LARGE
+	  || ix86_cmodel == CM_LARGE_PIC
+	  || flag_force_indirect_call
+	  || (TARGET_DLLIMPORT_DECL_ATTRIBUTES
+	      && DECL_DLLIMPORT_P (cfun->decl))))
     {
       /* Queue ENDBR insertion to x86_function_profiler.  */
       if (crtl->profile && flag_fentry)
diff --git a/gcc/testsuite/gcc.target/i386/pr94417-1.c b/gcc/testsuite/gcc.target/i386/pr94417-1.c
new file mode 100644
index 00000000000..5bbe057fa8f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr94417-1.c
@@ -0,0 +1,20 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-O2 -fcf-protection -mcmodel=large" } */
+/* { dg-final { scan-assembler-times {\mendbr} 2 } } */
+
+extern void ext (void);
+
+__attribute((noclone, noinline))
+static
+void
+foo (void)
+{
+  ext ();
+}
+
+void
+bar (void)
+{
+  foo ();
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr94417-2.c b/gcc/testsuite/gcc.target/i386/pr94417-2.c
new file mode 100644
index 00000000000..9eb0f5b2141
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr94417-2.c
@@ -0,0 +1,21 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target fpic } */
+/* { dg-options "-O2 -fpic -mcmodel=large -fcf-protection" } */
+/* { dg-final { scan-assembler-times {\mendbr} 2 } } */
+
+extern void ext (void);
+
+__attribute((noclone, noinline))
+static
+void
+foo (void)
+{
+  ext ();
+}
+
+void
+bar (void)
+{
+  foo ();
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr94417-3.c b/gcc/testsuite/gcc.target/i386/pr94417-3.c
new file mode 100644
index 00000000000..07c451796c2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr94417-3.c
@@ -0,0 +1,19 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcf-protection -mforce-indirect-call" } */
+/* { dg-final { scan-assembler-times {\mendbr} 2 } } */
+
+extern void ext (void);
+
+__attribute((noclone, noinline))
+static
+void
+foo (void)
+{
+  ext ();
+}
+
+void
+bar (void)
+{
+  foo ();
+}