Re: [PATCH] Use PIE_SPEC/NO_PIE_SPEC for crtend.o/crtendS.o

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Thu, Jun 25, 2015 at 4:37 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Wed, Jun 10, 2015 at 6:20 AM, Rainer Orth
> <ro@cebitec.uni-bielefeld.de> wrote:
>> "H.J. Lu" <hjl.tools@gmail.com> writes:
>>
>>> On Tue, May 19, 2015 at 8:33 AM, Joseph Myers <joseph@codesourcery.com> wrote:
>>>> On Tue, 19 May 2015, H.J. Lu wrote:
>>>>
>>>>> > I think the whole thing should be posted as one patch, with both the
>>>>> > target-independent changes and the target-specific changes for all
>>>>> > targets.
>>>>> >
>>>>>
>>>>> That is what makes me concerned.  I have some simple target-specified
>>>>> patches which weren't reviewed for years. What will happen if no one
>>>>
>>>> For any unreviewed patch, keep pinging weekly.
>>>>
>>>>> reviews some simple target-specified changes due to
>>>>>
>>>>> 1. Reviewers don't have access to those targets.
>>>>> 2. Target maintainers aren't review them.
>>>>> 3. There are no clear maintainers for those targets.
>>>>
>>>> I've already said in
>>>> <https://gcc.gnu.org/ml/gcc-patches/2015-05/msg00593.html> that, given
>>>> target maintainers CC:ed, I might be inclined to approve the patch on the
>>>> basis of allowing them a week to test their target changes.
>>>>
>>>
>>> Here is the complete patch.  Tested on Linux/x86-64.  It is also
>>> available on hjl/pie/master branch in git mirror.
>>
>> I just noticed that with --enable-default-pie, while crtbeginS.o is
>> linked into the executable, crtend.o is used, while with an explicit
>> -pie, crtendS.o is taken.  Shouldn't GNU_USER_TARGET_ENDFILE_SPEC have
>> the same treatment as GNU_USER_TARGET_STARTFILE_SPEC already did?
>>
>>         * config/gnu-user.h (GNU_USER_TARGET_STARTFILE_SPEC): Use
>>         PIE_SPEC and NO_PIE_SPEC if HAVE_LD_PIE is defined.
>>
>
> Here is a patch.  OK for trunk?
>

This patch requires:

https://gcc.gnu.org/ml/gcc-patches/2015-06/msg01782.html

since "pie" may not be used in any SPECs.  Here is the updated
combined patch.  OK to install?

Thanks.

-- 
H.J.

From 130ebd65884ae2ca4507ed6c689206d46a568e9f Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 25 Jun 2015 03:04:56 -0700
Subject: [PATCH] Use PIE_SPEC/NO_PIE_SPEC for crtend.o/crtendS.o

We need to link with crtend.o and crtendS.o properly for GCC configured
to generate PIE by default.  When PIE is enabled by default, -pie is
treated as nop in driver.  We should simply validate it, instead of issue
an error, since "pie" may not be used in any SPECs.

	* gcc.c (driver_handle_option): Validate -pie if PIE is enabled
	by default.
	* config/gnu-user.h (GNU_USER_TARGET_ENDFILE_SPEC): Use
	PIE_SPEC and NO_PIE_SPEC if HAVE_LD_PIE is defined.
---
 gcc/config/gnu-user.h | 9 +++++++++
 gcc/gcc.c             | 5 +++++
 2 files changed, 14 insertions(+)

diff --git a/gcc/config/gnu-user.h b/gcc/config/gnu-user.h
index 2fcb55d..5b3576b 100644
--- a/gcc/config/gnu-user.h
+++ b/gcc/config/gnu-user.h
@@ -67,11 +67,20 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    object constructed before entering `main', followed by a normal
    GNU userspace "finalizer" file, `crtn.o'.  */
 
+#if defined HAVE_LD_PIE
+#define GNU_USER_TARGET_ENDFILE_SPEC \
+  "%{fvtable-verify=none:%s; \
+     fvtable-verify=preinit:vtv_end_preinit.o%s; \
+     fvtable-verify=std:vtv_end.o%s} \
+   %{shared:crtendS.o%s;: %{" PIE_SPEC ":crtendS.o%s} \
+   %{" NO_PIE_SPEC ":crtend.o%s}} crtn.o%s"
+#else
 #define GNU_USER_TARGET_ENDFILE_SPEC \
   "%{fvtable-verify=none:%s; \
      fvtable-verify=preinit:vtv_end_preinit.o%s; \
      fvtable-verify=std:vtv_end.o%s} \
    %{shared|pie:crtendS.o%s;:crtend.o%s} crtn.o%s"
+#endif
 #undef  ENDFILE_SPEC
 #define ENDFILE_SPEC GNU_USER_TARGET_ENDFILE_SPEC
 
diff --git a/gcc/gcc.c b/gcc/gcc.c
index d77c6c5..0f29b78 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -3893,6 +3893,11 @@ driver_handle_option (struct gcc_options *opts,
       save_switch ("-o", 1, &arg, validated, true);
       return true;
 
+#ifdef ENABLE_DEFAULT_PIE
+    case OPT_pie:
+      /* -pie is turned on by default.  */
+#endif
+
     case OPT_static_libgcc:
     case OPT_shared_libgcc:
     case OPT_static_libgfortran:
-- 
2.1.0