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Re: [PATCH][1-3] New configure options that make the compiler use -fPIE and -pie as default option


fredag 01 augusti 2014 10.52.27 skrev  Rainer Orth:
> Hi Magnus,
> 
> a couple of comments, mostly nits.
> 
> > 2014-07-31  Magnus Granberg  <zorry@gentoo.org>
> > 
> > 	/gcc
> > 	* config/gnu-user.h: Define PIE_DRIVER_SELF_SPECS for PIE
> > 	as default and GNU_DRIVER_SELF_SPECS.
> > 	* config/i386/gnu-user-common.h: Define DRIVER_SELF_SPECS
> > 	* configure.ac: Add new option that enable PIE as default.
> > 	* configure, config.in: Rebuild.
> > 	* Makefile.in: Disable PIE when building the compiler.
> > 	* doc/install.texi: Add the new configure option default PIE.
> > 	* doc/invoke.texi: Add note for the new configure option default PIE.
> 
> Many of those entries are mis-formatted.  See other examples and the GNU
> Coding Standards for details.  E.g. the first would be
> 
> 	* config/gnu-user.h (PIE_DRIVER_SELF_SPECS): Define.
> 
> In general, you need to mention which macro, variable, manual section
> you change.  Emacs' add-change-log-entry does the basics for you.
> Besides, you only state what changed, not why.
> 
> Apart from that, I don't think defining PIE_DRIVER_SELF_SPECS in
> gnu-user.h is a good idea.  This way, every other target supporting the
> option would have to duplicate that stuff.
> 
> 	* testsuite/gcc/default-pie.c: New test for new configure option
> 	--enale-default-pie
> 
> gcc/testsuite has its own ChangeLog file.  Typo for --enale-...
> 
> 	* testsuite/gcc.dg/other/anon5.C: Add skip test as it fail to link
> 	on effective_target default_pie.
> 
> should be
> 
> 	* g++.dg/other/anon5.C: Skip if default_pie.
> 
> No explanations in ChangeLog entries; they belong into the code.
> Besides, you had the first dir component wrong.  Again, Emacs does this
> for you.
> 
> 	* testsuite/lib/target-supports.exp (check_profiling_available):
> 	We can't use profiling on effective target default_pie.
> 	(check_effective_target_pie): Add check_effective_target_default_pie.
> 
> Wrong: should be
> 
> 	* lib/target-supports.exp (check_effective_target_default_pie):
>         New proc.
> 
> The new default_pic effective-target keyword needs to be documented in
> doc/sourcebuild.texi.
> 
> --- a/gcc/testsuite/gcc.dg/default-pie.c	2013-11-09 21:07:16.741479728 
+0100
> +++ b/gcc/testsuite/gcc.dg/default-pie.c	2013-11-09 21:05:07.801479218
> +0100 @@ -0,0 +1,12 @@
> +/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
> +/* { dg-require-effective-target default_pie } */
> 
> Why restrict to Linux, GNU?  default_pie should be enough once other
> targets add this.
> 
> --- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-store-ccp-3.c	2012-03-14
> 17:33:37.000000000 +0100 +++
> b/gcc/testsuite/gcc.dg/tree-ssa/ssa-store-ccp-3.c	2014-07-29
> 00:55:17.421086416 +0200 @@ -2,6 +2,9 @@
>  /* Skipped on MIPS GNU/Linux target because __PIC__ can be
>     defined for executables as well as shared libraries.  */
>  /* { dg-skip-if "" { *-*-darwin* hppa*64*-*-* mips*-*-linux* *-*-mingw* } {
> "*" } { "" } } */ +/* Skipped on default_pie targets because __PIC__ is
> +   defined for executables.  */
> +/* { dg-skip-if "" { default_pie } { "*" } { "" } }  */
> 
> Emit those default args, they're unnecessary.  Also in g++.dg/other/anon5.C.
> 
> --- a/gcc/testsuite/g++.dg/other/anon5.C	2012-11-10 15:34:42.000000000 +0100
> +++ b/gcc/testsuite/g++.dg/other/anon5.C	2013-11-09 14:49:52.281390127
> +0100 @@ -1,5 +1,6 @@
>  // PR c++/34094
>  // { dg-do link { target { ! { *-*-darwin* *-*-hpux* *-*-solaris2.* } } } }
> +// { dg-skip-if "" { default_pie } { "*" } { "" } }
> 
> The first arg to dg-skip-if should explain why you're skipping the test.
> 
> --- a/gcc/testsuite/lib/target-supports.exp	2013-10-01 11:18:30.000000000
> +0200 +++ b/gcc/testsuite/lib/target-supports.exp	2013-10-25
> 22:01:46.743388469 +0200 @@ -474,6 +474,11 @@ proc
> check_profiling_available { test_wh
>  	}
>      }
> 
> +    # Profiling don't work with default -fPIE -pie.
> 
> Grammar: "doesn't work".
> 
> +# Return 1 if -pie, -fPIE are default enable, 0 otherwise.
> +
> +proc check_effective_target_default_pie { } {
> 
> Hard to understand, perhaps
> 
> # Return 1 if -pie -fPIE are enabled by default, 0 otherwise.
> 
> --- a/gcc/doc/invoke.texi	2013-10-03 19:13:50.000000000 +0200
> +++ b/gcc/doc/invoke.texi	2013-11-17 21:30:02.784220111 +0100
> @@ -10535,6 +10535,12 @@ For predictable results, you must also s
>  used for compilation (@option{-fpie}, @option{-fPIE},
>  or model suboptions) when you specify this linker option.
> 
> +NOTE: With configure --enable-default-pie this option is enabled by default
> 
> With the @option{--enable-default-pie} configure option, ...
> 
> +for C, C++, ObjC, ObjC++, if none of @option{-fno-PIE}, @option{-fno-pie},
> +@option{-fPIC}, @option{-fpic}, @option{-fno-PIC}, @option{-fno-pic},
> +@option{-nostdlib}, @option{-nostartfiles}, @option{-shared},
> +@option{-nodefaultlibs}, nor @option{static} are found.
> 
> @option{-static}.
> 
> 	Rainer
Thanks Rainer for the nits and comments.
Have updated the patches and Changelogs.
But i still use PIE_DRIVER_SELF_SPECS, do you have a ide where move it so
i don't need to duplicate that stuff or how to do it?

Magnus G

2014-11-10  Magnus Granberg  <zorry@gentoo.org>

	/gcc
	* config/gnu-user.h (PIE_DRIVER_SELF_SPECS) and 
	(GNU_DRIVER_SELF_SPECS): Define.
	* config/i386/gnu-user-common.h (DRIVER_SELF_SPECS): Define
	* configure.ac: Add new option.
	* configure, config.in: Rebuild.
	* Makefile.in (ALL_CFLAGS) and (ALL_CXXFLAGS): Disable PIE.
	* doc/install.texi: New configure option.
	* doc/invoke.texi: Add note to PIE.
	* doc/sourcebuild.texi: New effective target.
	gcc/testsuite
	* gcc/default-pie.c: New test
	* gcc.dg/tree-ssa/ssa-store-ccp-3.c: Skip if default_pie
	* g++.dg/other/anon5.C: Skip if default_pie
	* lib/target-supports.exp (check_effective_target_default_pie):
	New proc.
	/libgcc
	* Makefile.in (CRTSTUFF_CFLAGS): Disable PIE.
--- a/gcc/doc/install.texi	2013-10-01 19:29:40.000000000 +0200
+++ b/gcc/doc/install.texi	2013-11-17 16:13:20.474144921 +0100
@@ -1455,6 +1455,10 @@ do a @samp{make -C gcc gnatlib_and_tools
 Specify that the run-time libraries for stack smashing protection
 should not be built.
 
+@item --enable-default-pie
+Turn on @option{-fPIE} and @option{-pie} by default if supported.
+Currently supported targets are i?86-*-linux* and x86-64-*-linux*.
+
 @item --disable-libquadmath
 Specify that the GCC quad-precision math library should not be built.
 On some systems, the library is required to be linkable when building
--- a/gcc/doc/invoke.texi	2013-10-03 19:13:50.000000000 +0200
+++ b/gcc/doc/invoke.texi	2013-11-17 21:30:02.784220111 +0100
@@ -10535,6 +10535,13 @@ For predictable results, you must also s
 used for compilation (@option{-fpie}, @option{-fPIE},
 or model suboptions) when you specify this linker option.
 
+@emph{Note}: With the @option{--enable-default-pie} configure option, this
+options is enabled by default for C, C++, ObjC, ObjC++, if none of
+@option{-fno-PIE}, @option{-fno-pie}, @option{-fPIC}, @option{-fpic},
+@option{-fno-PIC}, @option{-fno-pic}, @option{-nostdlib},
+@option{-nostartfiles}, @option{-shared}, @option{-nodefaultlibs},
+nor @option{-static} are found.
+
 @item -rdynamic
 @opindex rdynamic
 Pass the flag @option{-export-dynamic} to the ELF linker, on targets
@@ -22476,6 +22476,13 @@ used during linking.
 @code{__pie__} and @code{__PIE__}.  The macros have the value 1
 for @option{-fpie} and 2 for @option{-fPIE}.
 
+@emph{Note}: With the @option{--enable-default-pie} configure option, this
+options is enabled by default for C, C++, ObjC, ObjC++, if none of
+@option{-fno-PIE}, @option{-fno-pie}, @option{-fPIC}, @option{-fpic},
+@option{-fno-PIC}, @option{-fno-pic}, @option{-nostdlib},
+@option{-nostartfiles}, @option{-shared}, @option{-nodefaultlibs},
+nor @option{-static} are found.
+
 @item -fno-jump-tables
 @opindex fno-jump-tables
 Do not use jump tables for switch statements even where it would be
--- a/gcc/doc/sourcebuild.texi	2014-08-20 17:56:45.000000000 +0200
+++ b/gcc/doc/sourcebuild.texi	2014-11-09 23:43:06.254817553 +0100
@@ -1881,6 +1881,9 @@ Target supports @option{-mpe-aligned-com
 @item pie
 Target supports @option{-pie}, @option{-fpie} and @option{-fPIE}.
 
+@item default_pie
+Target enable @option{-pie}, and @option{-fPIE} as default.
+
 @item section_anchors
 Target supports section anchors.
 
--- a/gcc/config/gnu-user.h	2013-08-20 10:31:40.000000000 +0200
+++ b/gcc/config/gnu-user.h	2013-10-23 22:01:42.337238981 +0200
@@ -126,3 +126,17 @@ see the files COPYING3 and COPYING.RUNTI
   LD_STATIC_OPTION " --whole-archive -ltsan --no-whole-archive " \
   LD_DYNAMIC_OPTION "}}%{!static-libtsan:-ltsan}"
 #endif
+
+/* We use this to make the compiler use -fPIE as default and link
+   with -pie.  */
+#ifdef ENABLE_DEFAULT_PIE
+#define PIE_DRIVER_SELF_SPECS \
+"%{pie|fpic|fPIC|fpie|fPIE|fno-pic|fno-PIC|fno-pie|fno-PIE| \
+  shared|static|nostdlib|nodefaultlibs|nostartfiles:;:-fPIE -pie}"
+#else
+#define PIE_DRIVER_SELF_SPECS ""
+#endif
+
+#ifndef GNU_DRIVER_SELF_SPECS
+#define GNU_DRIVER_SELF_SPECS PIE_DRIVER_SELF_SPECS
+#endif
--- a/gcc/config/i386/gnu-user-common.h	2013-01-10 21:38:27.000000000 +0100
+++ b/gcc/config/i386/gnu-user-common.h	2013-10-23 17:37:45.432767049 +0200
@@ -70,3 +70,8 @@ along with GCC; see the file COPYING3.
 
 /* Static stack checking is supported by means of probes.  */
 #define STACK_CHECK_STATIC_BUILTIN 1
+
+/* Use GNU_DRIVER_SELF_SPECS.  */
+#ifndef DRIVER_SELF_SPECS
+#define DRIVER_SELF_SPECS GNU_DRIVER_SELF_SPECS
+#endif
--- a/gcc/configure.ac	2014-04-28 16:01:40.000000000 +0200
+++ b/gcc/configure.ac	2014-05-08 02:42:30.900883247 +0200
@@ -5671,6 +5671,36 @@ if test x"${LINKER_HASH_STYLE}" != x; th
                                          [The linker hash style])
 fi
 
+# Check whether --enable-default-pie was given and target have the support.
+AC_ARG_ENABLE(default-pie,
+[AS_HELP_STRING([--enable-default-pie],
+  [enable Position Independent Executable as default])],
+enable_default_pie=$enableval,
+enable_default_pie=no)
+if test x$enable_default_pie = xyes; then
+  AC_MSG_CHECKING(if $target supports default PIE)
+  enable_default_pie=no
+  case $target in
+    i?86*-*-linux* | x86_64*-*-linux*)
+      saved_LDFLAGS="$LDFLAGS"
+      saved_CFLAGS="$CFLAGS"
+      CFLAGS="$CFLAGS -fPIE"
+      LDFLAGS="$LDFLAGS -fPIE -pie"
+      AC_TRY_LINK(,,[enable_default_pie=yes],)
+      LDFLAGS="$saved_LDFLAGS"
+      CFLAGS="$saved_CFLAGS"
+      ;;
+    *)
+      ;;
+    esac
+  AC_MSG_RESULT($enable_default_pie)
+fi
+if test x$enable_default_pie == xyes ; then
+  AC_DEFINE(ENABLE_DEFAULT_PIE, 1,
+      [Define if your target supports default PIE and it is enabled.])
+fi
+AC_SUBST([enable_default_pie])
+
 # Configure the subdirectories
 # AC_CONFIG_SUBDIRS($subdirs)
 
--- a/gcc/Makefile.in	2013-10-02 21:52:27.000000000 +0200
+++ b/gcc/Makefile.in	2013-10-24 17:46:22.055357122 +0200
@@ -968,14 +968,23 @@ CONTEXT_H = context.h
 # cross compiler which does not use the native headers and libraries.
 INTERNAL_CFLAGS = -DIN_GCC $(PICFLAG) @CROSS@
 
+# We don't want to compile the compiler with -fPIE, it make PCH fail.
+enable_default_pie = @enable_default_pie@
+ifeq ($(enable_default_pie),yes)
+NOPIE_CFLAGS = -fno-PIE
+else
+NOPIE_CFLAGS=
+endif
+
 # This is the variable actually used when we compile. If you change this,
 # you probably want to update BUILD_CFLAGS in configure.ac
-ALL_CFLAGS = $(T_CFLAGS) $(CFLAGS-$@) \
+ALL_CFLAGS = $(NOPIE_CFLAGS) $(T_CFLAGS) $(CFLAGS-$@) \
   $(CFLAGS) $(INTERNAL_CFLAGS) $(COVERAGE_FLAGS) $(WARN_CFLAGS) @DEFS@
 
 # The C++ version.
-ALL_CXXFLAGS = $(T_CFLAGS) $(CFLAGS-$@) $(CXXFLAGS) $(INTERNAL_CFLAGS) \
-  $(COVERAGE_FLAGS) $(NOEXCEPTION_FLAGS) $(WARN_CXXFLAGS) @DEFS@
+ALL_CXXFLAGS = $(NOPIE_CFLAGS) $(T_CFLAGS) $(CFLAGS-$@) $(CXXFLAGS) \
+  $(INTERNAL_CFLAGS) $(COVERAGE_FLAGS) $(NOEXCEPTION_FLAGS) \
+  $(WARN_CXXFLAGS) @DEFS@
 
 # Likewise.  Put INCLUDES at the beginning: this way, if some autoconf macro
 # puts -I options in CPPFLAGS, our include files in the srcdir will always
@@ -1831,6 +1831,7 @@ libgcc.mvars: config.status Makefile spe
 	echo GCC_CFLAGS = '$(GCC_CFLAGS)' >> tmp-libgcc.mvars
 	echo INHIBIT_LIBC_CFLAGS = '$(INHIBIT_LIBC_CFLAGS)' >> tmp-libgcc.mvars
 	echo TARGET_SYSTEM_ROOT = '$(TARGET_SYSTEM_ROOT)' >> tmp-libgcc.mvars
+	echo enable_default_pie = '$(enable_default_pie)' >> tmp-libgcc.mvars
 
 	mv tmp-libgcc.mvars libgcc.mvars
 
@@ -3536,6 +3536,9 @@ site.exp: ./config.status Makefile
 	@if test "@enable_lto@" = "yes" ; then \
 	  echo "set ENABLE_LTO 1" >> ./site.tmp; \
 	fi
+	@if test "@enable_default_pie@" = "yes" ; then \
+	  echo "set ENABLE_DEFAULT_PIE 1" >> ./site.tmp; \
+	fi
 # If newlib has been configured, we need to pass -B to gcc so it can find
 # newlib's crt0.o if it exists.  This will cause a "path prefix not used"
 # message if it doesn't, but the testsuite is supposed to ignore the message -
--- a/libgcc/Makefile.in	2014-10-30 18:28:30.000000000 +0100
+++ b/libgcc/Makefile.in	2014-11-08 20:37:04.462496763 +0100
@@ -281,11 +281,19 @@ override CFLAGS := $(filter-out -fprofil
 INTERNAL_CFLAGS = $(CFLAGS) $(LIBGCC2_CFLAGS) $(HOST_LIBGCC2_CFLAGS) \
 		  $(INCLUDES) @set_have_cc_tls@ @set_use_emutls@
 
+#Don't use -fPIE when compiling crtbegin/end.
+ifeq ($(enable_default_pie),yes)
+NOPIE_CFLAGS = -fno-PIE
+else
+NOPIE_CFLAGS=
+endif
+
 # Options to use when compiling crtbegin/end.
 CRTSTUFF_CFLAGS = -O2 $(GCC_CFLAGS) $(INCLUDES) $(MULTILIB_CFLAGS) -g0 \
   -finhibit-size-directive -fno-inline -fno-exceptions \
   -fno-zero-initialized-in-bss -fno-toplevel-reorder -fno-tree-vectorize \
   -fbuilding-libgcc -fno-stack-protector $(FORCE_EXPLICIT_EH_REGISTRY) \
+  $(NOPIE_CFLAGS) \
   $(INHIBIT_LIBC_CFLAGS)
 
 # Extra flags to use when compiling crt{begin,end}.o.
--- a/gcc/testsuite/gcc.dg/default-pie.c	2013-11-09 21:07:16.741479728 +0100
+++ b/gcc/testsuite/gcc.dg/default-pie.c	2013-11-09 21:05:07.801479218 +0100
@@ -0,0 +1,11 @@
+/* { dg-require-effective-target default_pie } */
+/* { dg-options "-O2" } */
+int foo (void);
+
+int
+main (void)
+{
+	return foo ();
+}
+
+/* { dg-final { scan-assembler "foo@PLT" } } */
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-store-ccp-3.c	2012-03-14 17:33:37.000000000 +0100
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-store-ccp-3.c	2014-07-29 00:55:17.421086416 +0200
@@ -2,6 +2,7 @@
 /* Skipped on MIPS GNU/Linux target because __PIC__ can be
    defined for executables as well as shared libraries.  */
 /* { dg-skip-if "" { *-*-darwin* hppa*64*-*-* mips*-*-linux* *-*-mingw* } { "*" } { "" } } */
+/* { dg-skip-if "" { default_pie } { "*" } { "" } }  */
 /* { dg-options "-O2 -fno-common -fdump-tree-optimized" } */
 
 const int conststaticvariable;
--- a/gcc/testsuite/g++.dg/other/anon5.C	2012-11-10 15:34:42.000000000 +0100
+++ b/gcc/testsuite/g++.dg/other/anon5.C	2013-11-09 14:49:52.281390127 +0100
@@ -1,5 +1,6 @@
 // PR c++/34094
 // { dg-do link { target { ! { *-*-darwin* *-*-hpux* *-*-solaris2.* } } } }
+// { dg-skip-if "" { default_pie } { "*" } { "" } }
 // { dg-options "-g" }
 // Ignore additional message on powerpc-ibm-aix
 // { dg-prune-output "obtain more information" } */
--- a/gcc/testsuite/lib/target-supports.exp	2013-10-01 11:18:30.000000000 +0200
+++ b/gcc/testsuite/lib/target-supports.exp	2013-10-25 22:01:46.743388469 +0200
@@ -474,6 +474,11 @@ proc check_profiling_available { test_wh
 	}
     }
 
+    # Profiling doesn't work with default -fPIE -pie.
+    if { [check_effective_target_default_pie] } {
+      return 0
+    }
+
     # Support for -p on solaris2 relies on mcrt1.o which comes with the
     # vendor compiler.  We cannot reliably predict the directory where the
     # vendor compiler (and thus mcrt1.o) is installed so we can't
@@ -856,6 +856,14 @@ proc check_effective_target_pie { } {
     return 0
 }
 
+# Return 1 if -pie, -fPIE are enable by default, 0 otherwise.
+
+proc check_effective_target_default_pie { } {
+    global ENABLE_DEFAULT_PIE
+    return [info exists ENABLE_DEFAULT_PIE]
+    return 0
+}
+
 # Return true if the target supports -mpaired-single (as used on MIPS).
 
 proc check_effective_target_mpaired_single { } {

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