[Bug target/94417] New: -fcf-protection -mcmodel=large is broken

[Bug target/94417] New: -fcf-protection -mcmodel=large is broken

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

            Bug ID: 94417
           Summary: -fcf-protection -mcmodel=large is broken
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
  Target Milestone: ---
            Target: x86-64

From:

https://bugs.llvm.org/show_bug.cgi?id=45364

Testcase:

void ext();
__attribute((noinline)) static void a() { ext(); }
void b() { a(); }

Compile with "gcc -O2 -mcmodel=large -fcf-protection".  Note the indirect
call to "a", which does not have an endbr64.

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|-fcf-protection             |-fcf-protection
                   |-mcmodel=large is broken    |-mcmodel=large/-mforce-indi
                   |                            |rect-call is broken

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
-mforce-indirect-call has the same issue.

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-03-31

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
This seems to work:

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)

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |10.0
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2020-March/5
                   |                            |42984.html
           Keywords|                            |patch

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> ---
A patch is posted at

https://gcc.gnu.org/pipermail/gcc-patches/2020-March/542984.html

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by H.J. Lu <hjl@gcc.gnu.org>:

https://gcc.gnu.org/g:c5f379653964a1d2c7037b2de3e947a48370a198

commit r10-7633-gc5f379653964a1d2c7037b2de3e947a48370a198
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Apr 8 09:47:35 2020 -0700

    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.

    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.

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed for GCC 10.

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by H.J. Lu <hjl@gcc.gnu.org>:

https://gcc.gnu.org/g:4a745938b56da04ed01055d5bcb520dc1c760414

commit r9-8508-g4a745938b56da04ed01055d5bcb520dc1c760414
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Apr 17 15:23:27 2020 -0700

    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/

            Backport from master
            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)

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-8 branch has been updated by H.J. Lu <hjl@gcc.gnu.org>:

https://gcc.gnu.org/g:99ddb11c0840f68466a14fd583dd4d3a558d4961

commit r8-10186-g99ddb11c0840f68466a14fd583dd4d3a558d4961
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Apr 17 15:23:27 2020 -0700

    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/

            Backport from master
            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)

[Bug target/94417] -fcf-protection -mcmodel=large/-mforce-indirect-call is broken

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94417

--- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed for GCC 10, GCC 9.4 and GCC 8.5.