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
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Commit Message

Iain Buclaw via Gcc-patches March 31, 2020, 3:11 p.m.
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

-- 
2.25.1

Comments

Iain Buclaw via Gcc-patches April 8, 2020, 4:16 p.m. | #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
>
Iain Buclaw via Gcc-patches April 8, 2020, 4:23 p.m. | #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)).

-- 
H.J.
Iain Buclaw via Gcc-patches April 8, 2020, 4:41 p.m. | #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
>
Iain Buclaw via Gcc-patches April 17, 2020, 3:18 p.m. | #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.


-- 
H.J.
From f86e27e71fb963aaa95b1da31515f888f6e146f8 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 8 Apr 2020 09:47:35 -0700
Subject: [PATCH] x86: Insert ENDBR if function will be called indirectly

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.

NB: gcc.target/i386/pr94417-2.c is updated to expect 4 ENDBRs, instead
of 2, since only GCC 10 has the fix for PR target/89355 not to insert
ENDBR after NOTE_INSN_DELETED_LABEL.

gcc/

	Backport from master
	PR target/94417
	* config/i386/i386.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.

(cherry picked from commit c5f379653964a1d2c7037b2de3e947a48370a198)
---
 gcc/config/i386/i386.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

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 5d12d82db5b..3891d44ce85 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -2535,7 +2535,12 @@ 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..9e9c277e07f
--- /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} 4 } } */
+
+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 ();
+}
Iain Buclaw via Gcc-patches April 17, 2020, 10:15 p.m. | #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

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 ();
+}