[PATCH] PR61123 : Fix the ABI mis-matching error caused by LTO

["Hale Wang" <Hale dot Wang at arm dot com>]

Hi,

With LTO, -fno-short-enums is ignored, resulting in ABI mis-matching in
linking.

Refer https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61123  for details. 

This patch add fshort-enums and fshout-wchar to LTO group.

To check it, a new procedure object-readelf is added in
testsuite/lib/lto.exp and new lto tests are added in gcc.target/arm/lto.

Bootstrap and no make check regression on X86-64.

Patch also attached for convenience.  Is It ok for trunk?

Thanks and Best Regards,
Hale Wang

c-family/ChangeLog
2014-06-18 Hale Wang <hale.wang@arm.com>

                    PR lto/61123
                    *c.opt (fshort-enums): Add to LTO.
                    *c.opt (fshort-wchar): Likewise.

testsuite/ChangeLog
2014-06-18 Hale Wang <hale.wang@arm.com>

                    * gcc.target/arm/lto/: New folder to verify the LTO
option for ARM specific.
                    * gcc.target/arm/lto/pr61123-enum-size_0.c: New test
case.
                    * gcc.target/arm/lto/pr61123-enum-size_1.c: Likewise.
                    * gcc.target/arm/lto/lto.exp: New exp file used to test
LTO option for ARM specific.
                    * lib/lto.exp (object-readelf): New procedure used to
catch the enum size in the final executable.

Index: gcc/c-family/c.opt
===================================================================
--- gcc/c-family/c.opt     (revision 211394)
+++ gcc/c-family/c.opt  (working copy)
@@ -1189,11 +1189,11 @@
Use the same size for double as for float

 fshort-enums
-C ObjC C++ ObjC++ Optimization Var(flag_short_enums)
+C ObjC C++ ObjC++ LTO Optimization Var(flag_short_enums)
Use the narrowest integer type possible for enumeration types

 fshort-wchar
-C ObjC C++ ObjC++ Optimization Var(flag_short_wchar)
+C ObjC C++ ObjC++ LTO Optimization Var(flag_short_wchar)
Force the underlying type for \"wchar_t\" to be \"unsigned short\"

 fsigned-bitfields
Index: gcc/testsuite/gcc.target/arm/lto/pr61123-enum-size_0.c
===================================================================
--- gcc/testsuite/gcc.target/arm/lto/pr61123-enum-size_0.c       (revision
0)
+++ gcc/testsuite/gcc.target/arm/lto/pr61123-enum-size_0.c    (revision 0)
@@ -0,0 +1,22 @@
+/* { dg-lto-do link } */
+/* { dg-lto-options { { -fno-short-enums -Wl,-Ur,--no-enum-size-warning -Os
-nostdlib -flto } } } */
+
+#include <stdlib.h>
+
+enum enum_size_attribute
+{
+  small_size, int_size
+};
+
+struct debug_ABI_enum_size
+{
+  enum enum_size_attribute es;
+};
+
+int
+foo1 (struct debug_ABI_enum_size *x)
+{
+  return sizeof (x->es);
+}
+
+/* { dg-final { object-readelf Tag_ABI_enum_size int { target arm_eabi } }
} */
Index: gcc/testsuite/gcc.target/arm/lto/lto.exp
===================================================================
--- gcc/testsuite/gcc.target/arm/lto/lto.exp        (revision 0)
+++ gcc/testsuite/gcc.target/arm/lto/lto.exp     (revision 0)
@@ -0,0 +1,59 @@
+# Copyright (C) 2009-2014 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+#
+# Contributed by Diego Novillo <dnovillo@google.com>
+
+
+# Test link-time optimization across multiple files.
+#
+# Programs are broken into multiple files.  Each one is compiled
+# separately with LTO information.  The final executable is generated
+# by collecting all the generated object files using regular LTO or WHOPR.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+# Load procedures from common libraries.
+load_lib standard.exp
+load_lib gcc.exp
+
+# Load the language-independent compabibility support procedures.
+load_lib lto.exp
+
+# If LTO has not been enabled, bail.
+if { ![check_effective_target_lto] } {
+    return
+}
+
+gcc_init
+lto_init no-mathlib
+
+# Define an identifier for use with this suite to avoid name conflicts
+# with other lto tests running at the same time.
+set sid "c_lto"
+
+# Main loop.
+foreach src [lsort [find $srcdir/$subdir *_0.c]] {
+    # If we're only testing specific files and this isn't one of them, skip
it.
+    if ![runtest_file_p $runtests $src] then {
+             continue
+    }
+
+    lto-execute $src $sid
+}
+
+lto_finish
Index: gcc/testsuite/gcc.target/arm/lto/pr61123-enum-size_1.c
===================================================================
--- gcc/testsuite/gcc.target/arm/lto/pr61123-enum-size_1.c       (revision
0)
+++ gcc/testsuite/gcc.target/arm/lto/pr61123-enum-size_1.c    (revision 0)
@@ -0,0 +1,5 @@
+int
+foo2 (int y)
+{
+  return y*10;
+}
Index: gcc/testsuite/lib/lto.exp
===================================================================
--- gcc/testsuite/lib/lto.exp         (revision 211394)
+++ gcc/testsuite/lib/lto.exp      (working copy)
@@ -650,3 +650,82 @@
               fail "scan-symbol $args"
     }
}
+
+# Call pass if object readelf is ok, otherwise fail.
+# example: /* { dg-final { object-readelf Tag_ABI_enum_size int} } */
+proc object-readelf { args } {
+    global readelf
+    global base_dir
+             upvar 2 execname execname
+
+    if { [llength $args] < 2 } {
+                             error "object-readelf: too few arguments"
+        return
+    }
+    if { [llength $args] > 3 } {
+                             error "object-readelf: too many arguments"
+                             return
+    }
+    if { [llength $args] >= 3 } {
+             switch [dg-process-target [lindex $args 2]] {
+                 "S" { }
+                 "N" { return }
+                 "F" { setup_xfail "*-*-*" }
+                 "P" { }
+             }
+    }
+
+    # Find size like we find g++ in g++.exp.
+    if ![info exists readelf]  {
+             set readelf [findfile $base_dir/../../../binutils/readelf \
+                               $base_dir/../../../binutils/readelf \
+                               [findfile $base_dir/../../readelf
$base_dir/../../readelf \
+                                [findfile $base_dir/readelf
$base_dir/readelf \
+                                 [transform readelf]]]]
+             verbose -log "readelf is $readelf"
+    }
+
+    set what [lindex $args 0]
+             set with [lindex $args 1]
+
+    if ![file_on_host exists $execname] {
+             verbose -log "$execname does not exist"
+             unresolved "object-readelf $what "
+             return
+    }
+
+    set output [remote_exec host "$readelf -A" "$execname"]
+    set status [lindex $output 0]
+    if { $status != 0 } {
+        verbose -log "object-readelf: $readelf failed"
+        unresolved "object-readelf $what $execname"
+        return
+    }
+
+    set text [lindex $output 1]
+    set lines [split $text "\n"]
+
+             set done 0
+             set i 0
+             while { !$done } {
+                             set line_tex [lindex $lines $i]
+                             if { [llength ${line_tex}] > 1} {
+                                             incr i
+                                             if [regexp -- $what $line_tex]
{
+                                                             set match
[regexp -- $with $line_tex]
+                                                             set done 1
+                                             }
+                             } else {
+                                             set done 1
+                             }
+             }
+
+    verbose -log "$what size is $with;"
+    if { $match == 1 } {
+             pass "object-readelf $what size is correct."
+    } else {
+             fail "object-readelf $what size is incorrect."
+    }
+}
+
+

Attachment: ABI-mismatching-lto.patch
Description: Binary data