## DP: Description: http://sourceware.org/ml/binutils/2010-09/msg00216.html 

2010-09-15  Maciej W. Rozycki  <macro@codesourcery.com>

	PR ld/10144

	bfd/
	* elfxx-mips.c (_bfd_mips_elf_check_relocs)
	[R_MIPS_32, R_MIPS_REL32, R_MIPS_64]: Ignore relocs from
	SEC_DEBUGGING sections.

	ld/testsuite/
	* lib/ld-lib.exp (run_ld_link_tests): Handle sources from other
	directories.
	(run_ld_link_exec_tests): Likewise.
	(run_cc_link_tests): Likewise.
	* ld-elf/comm-data1.sd: New test.
	* ld-elf/comm-data1.s: Source for the new test.
	* ld-elf/comm-data2.sd: New test.
	* ld-elf/comm-data2.rd: Likewise.
	* ld-elf/comm-data2.xd: Likewise.
	* ld-elf/comm-data2.s: Source for the new tests.
	* ld-elf/comm-data.exp: Run the new tests.
	* ld-mips-elf/comm-data.exp: Likewise.

--- /dev/null
+++ b/ld/testsuite/ld-elf/comm-data1.s
@@ -0,0 +1,6 @@
+	.section .rodata,"a",%progbits
+	.balign	8
+	.globl	foo
+	.type	foo,%object
+foo:
+	.skip	4, 0
--- /dev/null
+++ b/ld/testsuite/ld-elf/comm-data2.xd
@@ -0,0 +1,2 @@
+Hex dump of section '\.debug_foo':
+ +0x0+ +00000000 00000000 00000000 00000000 +\.\.\.\.\.\.\.\.\.\.\.\.\.\.\.\.
--- /dev/null
+++ b/ld/testsuite/ld-elf/comm-data2.s
@@ -0,0 +1,14 @@
+	.text
+	.globl	_start
+	.globl	__start
+_start:
+__start:
+	.comm	foo, 4, 4
+	.section .debug_foo,"",%progbits
+	.balign	16
+	.ifdef	ELF64
+	.8byte	foo
+	.else
+	.4byte	foo
+	.endif
+	.balign	16
--- /dev/null
+++ b/ld/testsuite/ld-elf/comm-data.exp
@@ -0,0 +1,76 @@
+# Expect script for common symbol override.
+#
+#   Copyright 2010  Free Software Foundation, Inc.
+#
+# This file is part of the GNU Binutils.
+#
+# 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 this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+# MA 02110-1301, USA.
+#
+
+#
+# Written by Maciej W. Rozycki <macro@codesourcery.com>
+#
+
+# Exclude non-ELF targets.
+if ![is_elf_format] {
+    return
+}
+
+# Exclude non-Linux targets; feel free to include your favourite one
+# if you like.
+if ![istarget *-*-linux*] {
+    return
+}
+
+set testname "Common symbol override test"
+
+# Define a global symbol.
+run_ld_link_tests [list \
+    [list \
+	"$testname (auxiliary shared object build)" \
+	"-shared" \
+	"" \
+	{ comm-data1.s } \
+	{ \
+	    { readelf -s comm-data1.sd } \
+	} \
+	"libcomm-data.so" \
+    ] \
+]
+
+# Set the pointer size according to the ELF flavour.
+set AFLAGS ""
+if [is_elf64 "tmpdir/libcomm-data.so"] {
+    append AFLAGS " --defsym ELF64=1"
+}
+
+# Verify that a common symbol has been converted to an undefined
+# reference to the global symbol of the same name defined above
+# and that the debug reference has been dropped.
+run_ld_link_tests [list \
+    [list \
+	"$testname" \
+	"-Ltmpdir -lcomm-data" \
+	"$AFLAGS" \
+	{ comm-data2.s } \
+	{ \
+	    { readelf -s comm-data2.sd } \
+	    { readelf -r comm-data2.rd } \
+	    { readelf "-x .debug_foo" comm-data2.xd } \
+	} \
+	"comm-data" \
+    ] \
+]
--- /dev/null
+++ b/ld/testsuite/ld-elf/comm-data1.sd
@@ -0,0 +1,10 @@
+Symbol table '\.dynsym' contains [0-9]+ entries:
+ +Num: +Value +Size +Type +Bind +Vis +Ndx +Name
+#...
+ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +[0-9]+ +foo
+#...
+Symbol table '\.symtab' contains [0-9]+ entries:
+ +Num: +Value +Size +Type +Bind +Vis +Ndx +Name
+#...
+ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +[0-9]+ +foo
+#pass
--- /dev/null
+++ b/ld/testsuite/ld-elf/comm-data2.rd
@@ -0,0 +1 @@
+There are no relocations in this file\.
--- /dev/null
+++ b/ld/testsuite/ld-elf/comm-data2.sd
@@ -0,0 +1,10 @@
+Symbol table '\.dynsym' contains [0-9]+ entries:
+ +Num: +Value +Size +Type +Bind +Vis +Ndx +Name
+#...
+ +[0-9]+: +0+ +0 +OBJECT +GLOBAL +DEFAULT +UND +foo
+#...
+Symbol table '\.symtab' contains [0-9]+ entries:
+ +Num: +Value +Size +Type +Bind +Vis +Ndx +Name
+#...
+ +[0-9]+: +0+ +0 +OBJECT +GLOBAL +DEFAULT +UND +foo
+#pass
--- a/ld/testsuite/lib/ld-lib.exp
+++ b/ld/testsuite/lib/ld-lib.exp
@@ -1252,11 +1252,12 @@
 
 	# Assemble each file in the test.
 	foreach src_file $src_files {
-	    set objfile "tmpdir/[file rootname $src_file].o"
+	    set fileroot "[file rootname [file tail $src_file]]"
+	    set objfile "tmpdir/$fileroot.o"
 	    lappend objfiles $objfile
 
 	    if { [file extension $src_file] == ".c" } {
-		set as_file "tmpdir/[file rootname $src_file].s"
+		set as_file "tmpdir/$fileroot.s"
 		if ![ld_compile "$CC -S $CFLAGS $cflags" $srcdir/$subdir/$src_file $as_file] {
 		    set is_unresolved 1
 		    break
@@ -1446,7 +1447,8 @@
 
 	# Assemble each file in the test.
 	foreach src_file $src_files {
-	    set objfile "tmpdir/[file rootname $src_file].o"
+	    set fileroot "[file rootname [file tail $src_file]]"
+	    set objfile "tmpdir/$fileroot.o"
 	    lappend objfiles $objfile
 
 	    # We ignore warnings since some compilers may generate
@@ -1565,7 +1567,8 @@
 
 	# Compile each file in the test.
 	foreach src_file $src_files {
-	    set objfile "tmpdir/[file rootname $src_file].o"
+	    set fileroot "[file rootname [file tail $src_file]]"
+	    set objfile "tmpdir/$fileroot.o"
 	    lappend objfiles $objfile
 
 	    # We ignore warnings since some compilers may generate
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/comm-data.exp
@@ -0,0 +1,88 @@
+# Expect script for common symbol override, MIPS variation.
+#
+#   Copyright 2010  Free Software Foundation, Inc.
+#
+# This file is part of the GNU Binutils.
+#
+# 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 this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+# MA 02110-1301, USA.
+#
+
+#
+# Written by Maciej W. Rozycki <macro@codesourcery.com>
+#
+
+# Exclude non-ELF targets.
+if ![is_elf_format] {
+    return
+}
+
+# Exclude non-Linux targets; feel free to include your favourite one
+# if you like.
+if ![istarget mips*-*-linux*] {
+    return
+}
+
+proc mips_comm_data_test { abi flag emul reloc } {
+
+    set testname "MIPS $abi/$reloc common symbol override test"
+    set AFLAGS "$flag -EB"
+    set LDFLAGS "-m$emul"
+
+    # Define a global symbol.
+    run_ld_link_tests [list \
+	[list \
+	    "$testname (auxiliary shared object build)" \
+	    "$LDFLAGS -shared" \
+	    "$AFLAGS -call_shared" \
+	    { ../ld-elf/comm-data1.s } \
+	    { \
+		{ readelf -s ../ld-elf/comm-data1.sd } \
+	    } \
+	  "libmips-$abi-$reloc-comm-data.so" \
+	] \
+    ]
+
+    # Set the pointer size according to the ABI.
+    if { $abi == "n64" } {
+	append AFLAGS " --defsym ELF64=1"
+    }
+
+    # Verify that a common symbol has been converted to an undefined
+    # reference to the global symbol of the same name defined above
+    # and that the debug reference has been dropped.
+    run_ld_link_tests [list \
+	[list \
+	    "$testname" \
+	    "$LDFLAGS -z $reloc -Ltmpdir -lmips-$abi-$reloc-comm-data" \
+	    "$AFLAGS -call_nonpic" \
+	    { ../ld-elf/comm-data2.s } \
+	    { \
+		{ readelf -s ../ld-elf/comm-data2.sd } \
+		{ readelf -r ../ld-elf/comm-data2.rd } \
+		{ readelf "-x .debug_foo" ../ld-elf/comm-data2.xd } \
+	    } \
+	    "mips-$abi-$reloc-comm-data" \
+	] \
+    ]
+}
+
+set abis { o32 -32 elf32btsmip n32 -n32 elf32btsmipn32 n64 -64 elf64btsmip }
+set relocs { copyreloc nocopyreloc }
+foreach { abi flag emul } $abis {
+    foreach reloc $relocs {
+	mips_comm_data_test $abi $flag $emul $reloc
+    }
+}
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -7583,6 +7583,19 @@
 		elf_hash_table (info)->dynobj = dynobj = abfd;
 	      break;
 	    }
+	  /* Ignore relocs from SEC_DEBUGGING sections because such
+	     sections are not SEC_ALLOC and thus ld.so will not process
+	     them.  Don't set has_static_relocs for the corresponding
+	     symbol.
+
+	     This is needed in cases such as a global symbol definition
+	     in a shared library causing a common symbol from an object
+	     file to be converted to an undefined reference.  If that
+	     happens, then all the relocations against this symbol from
+	     SEC_DEBUGGING sections in the object file will resolve to
+	     nil.  */
+	  if ((sec->flags & SEC_DEBUGGING) != 0)
+	    break;
 	  /* Fall through.  */
 
 	default: