ChangeLog:

	PR lto/42776
	* configure.ac (--enable-lto): Refactor handling so libelf tests
	are only performed inside then-clause of ACX_ELF_TARGET_IFELSE,
	and allow LTO to be explicitly enabled on non-ELF platforms that
	are known to support it inside else-clause.
	* configure: Regenerate.

gcc/ChangeLog:

	PR lto/42776
	* configure.ac (gcc_cv_as_section_has_align): Set if installed
	binutils supports extended .section directive needed by LTO, or
	warn if older binutils found.
	(LTO_BINARY_READER): New AC_SUBST'd variable.
	(LTO_USE_LIBELF): Likewise.
	* gcc/config.gcc (lto_binary_reader): New target-specific configure
	variable.
	* gcc/Makefile.in (LTO_BINARY_READER): Import AC_SUBST'd autoconf var.
	(LTO_USE_LIBELF): Likewise.
	* configure: Regenerate.

	* collect2.c (is_elf): Rename from this ...
	(is_elf_or_coff): ... to this, and recognize and allow i386 COFF
	 object files in addition to ELF-formatted ones.
	(scan_prog_file): Caller updated.  Also allow for LTO info marker
	symbol to be prefixed or not by an extra underscore.

	* config/i386/t-cygming (winnt.o): Also depend on LTO_STREAMER_H.
	* config/i386/winnt.c: Also #include lto-streamer.h
	(i386_pe_asm_named_section): Specify 1-byte section alignment for
	LTO named sections.
	(i386_pe_asm_output_aligned_decl_common): Add comment.
	(i386_pe_maybe_record_exported_symbol): Allow decl arg to be NULL.

gcc/lto/ChangeLog:

	PR lto/42776
	* Make-lang.in (LTO_OBJS): Use LTO_BINARY_READER instead of
	hardcoding 'lto-elf.o'.
	($(LTO_EXE)): Use LTO_USE_LIBELF instead of hardcoding '-lelf'.

	* lto-coff.h: New file.
	* lto-coff.c: Likewise.

gcc/testsuite/ChangeLog:

	PR lto/42776
	* lib/lto.exp (lto_prune_vis_warns): New function.
	(lto-link-and-maybe-run): Call it.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@158762 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 57 insertions, 2 deletions

diff --git a/gcc/configure b/gcc/configure
index fc4013b98f8..0515812873d 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -671,6 +671,8 @@ subdirs
 slibdir
 dollar
 gcc_tooldir
+LTO_USE_LIBELF
+LTO_BINARY_READER
 enable_lto
 MAINT
 zlibinc
@@ -17092,7 +17094,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 17095 "configure"
+#line 17097 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -17198,7 +17200,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 17201 "configure"
+#line 17203 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -22942,6 +22944,48 @@ if test $gcc_cv_as_ix86_pe_secrel32 = yes; then
 $as_echo "#define HAVE_GAS_PE_SECREL32_RELOC 1" >>confdefs.h
 
 fi
+	# Test if the assembler supports the extended form of the .section
+	# directive that specifies section alignment.  LTO support uses this,
+	# but normally only after installation, so we warn but don't fail the
+	# configure if LTO is enabled but the assembler does not support it.
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for .section with alignment" >&5
+$as_echo_n "checking assembler for .section with alignment... " >&6; }
+if test "${gcc_cv_as_section_has_align+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  gcc_cv_as_section_has_align=no
+    if test $in_tree_gas = yes; then
+    if test $gcc_cv_gas_vers -ge `expr \( \( 2 \* 1000 \) + 20 \) \* 1000 + 1`
+  then gcc_cv_as_section_has_align=yes
+fi
+  elif test x$gcc_cv_as != x; then
+    echo '.section lto_test,"dr0"' > conftest.s
+    if { ac_try='$gcc_cv_as $gcc_cv_as_flags -fatal-warnings -o conftest.o conftest.s >&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+    then
+	gcc_cv_as_section_has_align=yes
+    else
+      echo "configure: failed program was" >&5
+      cat conftest.s >&5
+    fi
+    rm -f conftest.o conftest.s
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_section_has_align" >&5
+$as_echo "$gcc_cv_as_section_has_align" >&6; }
+
+	if test x$gcc_cv_as_section_has_align != xyes; then
+	  case ",$enable_languages," in
+	    *,lto,*)
+	      { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: LTO for $target requires binutils >= 2.20.1, but version found appears insufficient; LTO will not work until binutils is upgraded." >&5
+$as_echo "$as_me: WARNING: LTO for $target requires binutils >= 2.20.1, but version found appears insufficient; LTO will not work until binutils is upgraded." >&2;}
+	      ;;
+	  esac
+	fi
 	;;
     esac
 
@@ -25078,6 +25122,17 @@ $as_echo "#define ENABLE_LTO 1" >>confdefs.h
 
 		    enable_lto=yes
 
+		    # LTO needs to speak the platform's object file format, and has a
+		    # number of implementations of the required binary file access APIs.
+		    # ELF is the most common, and default.  We only link libelf if ELF
+		    # is indeed the selected format.
+		    LTO_BINARY_READER=${lto_binary_reader}
+		    LTO_USE_LIBELF=-lelf
+		    if test "x$lto_binary_reader" != "xlto-elf" ; then
+		      LTO_USE_LIBELF=
+		    fi
+
+
 		    ;;
 		*) ;;
 	esac