Properly implement STT_COMMON

The BFD configure option, --enable-elf-stt-common, can't be to used to
verify STT_COMMON implementation with the normal binutils build.  Instead,
this patch removes it from BFD.  It adds --elf-stt-common=[no|yes] to ELF
assembler/objcopy and adds -z common/-z nocommon to ld.

A configure option, --enable-elf-stt-common, is added to gas to specify
whether ELF assembler should generate common symbols with the STT_COMMON
type by default.

Since BSF_KEEP_G is never used, it is renamed to BSF_ELF_COMMON for ELF
common symbols.

bfd/

	PR ld/19645
	* bfd.c (bfd): Change flags to 20 bits.
	(BFD_CONVERT_ELF_COMMON): New.
	(BFD_USE_ELF_STT_COMMON): Likewise.
	(BFD_FLAGS_SAVED): Add BFD_CONVERT_ELF_COMMON and
	BFD_USE_ELF_STT_COMMON.
	(BFD_FLAGS_FOR_BFD_USE_MASK): Likewise.
	* configure.ac: Remove --enable-elf-stt-common.
	* elf.c (swap_out_syms): Choose STT_COMMON or STT_OBJECT for
	common symbol depending on BFD_CONVERT_ELF_COMMON and
	BFD_USE_ELF_STT_COMMON.
	* elfcode.h (elf_slurp_symbol_table): Set BSF_ELF_COMMON for
	STT_COMMON.
	* elflink.c (bfd_elf_link_mark_dynamic_symbol): Also check
	STT_COMMON.
	(elf_link_convert_common_type): New function.
	(elf_link_output_extsym): Choose STT_COMMON or STT_OBJECT for
	common symbol depending on BFD_CONVERT_ELF_COMMON and
	BFD_USE_ELF_STT_COMMON.  Set sym.st_info after sym.st_shndx.
	* elfxx-target.h (TARGET_BIG_SYM): Add BFD_CONVERT_ELF_COMMON
	and BFD_USE_ELF_STT_COMMON to object_flags.
	(TARGET_LITTLE_SYM): Likewise.
	* syms.c (BSF_KEEP_G): Renamed to ...
	(BSF_ELF_COMMON): This.
	* bfd-in2.h: Regenerated.
	* config.in: Likewise.
	* configure: Likewise.

binutils/

	PR ld/19645
	* NEWS: Mention --elf-stt-common= for objcopy.
	* doc/binutils.texi: Document --elf-stt-common= for objcopy.
	* objcopy.c (do_elf_stt_common): New.
	(command_line_switch): Add OPTION_ELF_STT_COMMON.
	(copy_options): Add --elf-stt-common=.
	(copy_usage): Add --elf-stt-common=.
	(copy_object): Also check do_elf_stt_common for ELF targets.
	(copy_file): Handle do_elf_stt_common.
	(copy_main): Handle OPTION_ELF_STT_COMMON.
	* readelf.c (apply_relocations): Support STT_COMMON.
	* testsuite/binutils-all/common-1.s: New file.
	* testsuite/binutils-all/common-1a.d: Likewise.
	* testsuite/binutils-all/common-1b.d: Likewise.
	* testsuite/binutils-all/common-1c.d: Likewise.
	* testsuite/binutils-all/common-1d.d: Likewise.
	* testsuite/binutils-all/common-1e.d: Likewise.
	* testsuite/binutils-all/common-1f.d: Likewise.
	* testsuite/binutils-all/common-2.s: Likewise.
	* testsuite/binutils-all/common-2a.d: Likewise.
	* testsuite/binutils-all/common-2b.d: Likewise.
	* testsuite/binutils-all/common-2c.d: Likewise.
	* testsuite/binutils-all/common-2d.d: Likewise.
	* testsuite/binutils-all/common-2e.d: Likewise.
	* testsuite/binutils-all/common-2f.d: Likewise.
	* testsuite/binutils-all/objcopy.exp
	(objcopy_test_elf_common_symbols): New proc.
	Run objcopy_test_elf_common_symbols for ELF targets

gas/

	PR ld/19645
	* NEWS: Mention --enable-elf-stt-common and --elf-stt-common=
	for ELF assemblers.
	* as.c (flag_use_elf_stt_common): New.
	(show_usage): Add --elf-stt-common=.
	(option_values): Add OPTION_ELF_STT_COMMON.
	(std_longopts): Add --elf-stt-common=.
	(parse_args): Handle --elf-stt-common=.
	* as.h (flag_use_elf_stt_common): New.
	* config.in: Regenerated.
	* configure: Likewise.
	* configure.ac: Add --enable-elf-stt-common and define
	DEFAULT_GENERATE_ELF_STT_COMMON.
	* gas/write.c (write_object_file): Set BFD_CONVERT_ELF_COMMON
	and BFD_USE_ELF_STT_COMMON if flag_use_elf_stt_common is set.
	* doc/as.texinfo: Document --elf-stt-common=.
	* testsuite/gas/elf/common3.s: New file.
	* testsuite/gas/elf/common3a.d: Likewise.
	* testsuite/gas/elf/common3b.d: Likewise.
	* testsuite/gas/elf/common4.s: Likewise.
	* testsuite/gas/elf/common4a.d: Likewise.
	* testsuite/gas/elf/common4b.d: Likewise.
	* testsuite/gas/i386/dw2-compress-3b.d: Likewise.
	* testsuite/gas/i386/dw2-compressed-3b.d: Likewise.
	* testsuite/gas/elf/elf.exp: Run common3a, common3b, common4a
	and common4b.
	* testsuite/gas/i386/dw2-compress-3.d: Renamed to ...
	* testsuite/gas/i386/dw2-compress-3a.d: This.  Pass
	--elf-stt-common=no to as.
	* testsuite/gas/i386/dw2-compressed-3.d: Renamed to ...
	* testsuite/gas/i386/dw2-compressed-3a.d: This.  Pass
	--elf-stt-common=no to as.
	* testsuite/gas/i386/i386.exp: Run dw2-compress-3a,
	dw2-compress-3b, dw2-compressed-3a and dw2-compressed-3b instead
	of dw2-compress-3 and dw2-compressed-3.

include/

	PR ld/19645
	* bfdlink.h (bfd_link_elf_stt_common): New enum.
	(bfd_link_info): Add elf_stt_common.

ld/

	PR ld/19645
	* NEWS: Mention -z common/-z nocommon for ELF targets.
	* emultempl/elf32.em (gld${EMULATION_NAME}_handle_option): Handle
	-z common and -z nocommon.
	* ld.texinfo: Document -z common/-z nocommon.
	* lexsup.c (elf_shlib_list_options): Add -z common/-z nocommon.
	* testsuite/ld-elf/tls_common.exp: Test --elf-stt-common=no and
	--elf-stt-common=yes with assembler.
	* testsuite/ld-elfcomm/common-1.s: New file.
	* testsuite/ld-elfcomm/common-1a.d: Likewise.
	* testsuite/ld-elfcomm/common-1b.d: Likewise.
	* testsuite/ld-elfcomm/common-1c.d: Likewise.
	* testsuite/ld-elfcomm/common-1d.d: Likewise.
	* testsuite/ld-elfcomm/common-1e.d: Likewise.
	* testsuite/ld-elfcomm/common-1f.d: Likewise.
	* testsuite/ld-elfcomm/common-2.s: Likewise.
	* testsuite/ld-elfcomm/common-2a.d: Likewise.
	* testsuite/ld-elfcomm/common-2b.d: Likewise.
	* testsuite/ld-elfcomm/common-2c.d: Likewise.
	* testsuite/ld-elfcomm/common-2d.d: Likewise.
	* testsuite/ld-elfcomm/common-2e.d: Likewise.
	* testsuite/ld-elfcomm/common-2f.d: Likewise.
	* testsuite/ld-elfcomm/common-3a.rd: Likewise.
	* testsuite/ld-elfcomm/common-3b.rd: Likewise.
	* testsuite/ld-i386/pr19645.d: Likewise.
	* testsuite/ld-i386/pr19645.s: Likewise.
	* testsuite/ld-x86-64/largecomm-1.s: Likewise.
	* testsuite/ld-x86-64/largecomm-1a.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1b.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1c.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1d.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1e.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1f.d: Likewise.
	* testsuite/ld-x86-64/pr19645.d: Likewise.
	* testsuite/ld-x86-64/pr19645.s: Likewise.
	* testsuite/ld-elfcomm/elfcomm.exp: Test --elf-stt-common=yes
	with assembler.
	(assembler_generates_commons): Removed.
	Run -z common/-z nocommon tests.  Run *.d tests.
	* testsuite/ld-i386/i386.exp: Run pr19645.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-x86-64/dwarfreloc.exp: Test --elf-stt-common with
	assembler.  Test STT_COMMON with readelf.

18 files changed, 169 insertions, 25 deletions

diff --git a/ld/testsuite/ld-elfcomm/common-1.s b/ld/testsuite/ld-elfcomm/common-1.s
new file mode 100644
index 0000000..97e2bf4
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-1.s
@@ -0,0 +1,3 @@
+	.data
+	.dc.a foobar
+	.comm foobar,30,4
diff --git a/ld/testsuite/ld-elfcomm/common-1a.d b/ld/testsuite/ld-elfcomm/common-1a.d
new file mode 100644
index 0000000..28ed86b
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-1a.d
@@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-1b.d b/ld/testsuite/ld-elfcomm/common-1b.d
new file mode 100644
index 0000000..f0d135a
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-1b.d
@@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-1c.d b/ld/testsuite/ld-elfcomm/common-1c.d
new file mode 100644
index 0000000..c2805c3
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-1c.d
@@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-1d.d b/ld/testsuite/ld-elfcomm/common-1d.d
new file mode 100644
index 0000000..33c5c43
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-1d.d
@@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-1e.d b/ld/testsuite/ld-elfcomm/common-1e.d
new file mode 100644
index 0000000..a296db3
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-1e.d
@@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-1f.d b/ld/testsuite/ld-elfcomm/common-1f.d
new file mode 100644
index 0000000..91b530a
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-1f.d
@@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-2.s b/ld/testsuite/ld-elfcomm/common-2.s
new file mode 100644
index 0000000..9e51c8e
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-2.s
@@ -0,0 +1,3 @@
+	.data
+	.dc.a foobar
+	.tls_common foobar,30,4
diff --git a/ld/testsuite/ld-elfcomm/common-2a.d b/ld/testsuite/ld-elfcomm/common-2a.d
new file mode 100644
index 0000000..aacaad4
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-2a.d
@@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-2b.d b/ld/testsuite/ld-elfcomm/common-2b.d
new file mode 100644
index 0000000..4cb9e8e
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-2b.d
@@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-2c.d b/ld/testsuite/ld-elfcomm/common-2c.d
new file mode 100644
index 0000000..c4ddd6a
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-2c.d
@@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-2d.d b/ld/testsuite/ld-elfcomm/common-2d.d
new file mode 100644
index 0000000..577c381
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-2d.d
@@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-2e.d b/ld/testsuite/ld-elfcomm/common-2e.d
new file mode 100644
index 0000000..e6a3649
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-2e.d
@@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-2f.d b/ld/testsuite/ld-elfcomm/common-2f.d
new file mode 100644
index 0000000..728a099
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-2f.d
@@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-3a.rd b/ld/testsuite/ld-elfcomm/common-3a.rd
new file mode 100644
index 0000000..5d75572
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-3a.rd
@@ -0,0 +1,6 @@
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/common-3b.rd b/ld/testsuite/ld-elfcomm/common-3b.rd
new file mode 100644
index 0000000..7859718
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/common-3b.rd
@@ -0,0 +1,6 @@
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
diff --git a/ld/testsuite/ld-elfcomm/dummy.s b/ld/testsuite/ld-elfcomm/dummy.s
new file mode 100644
index 0000000..403f980
--- /dev/null
+++ b/ld/testsuite/ld-elfcomm/dummy.s
@@ -0,0 +1 @@
+# Dummy
diff --git a/ld/testsuite/ld-elfcomm/elfcomm.exp b/ld/testsuite/ld-elfcomm/elfcomm.exp
index 81fd520..926b98c 100644
--- a/ld/testsuite/ld-elfcomm/elfcomm.exp
+++ b/ld/testsuite/ld-elfcomm/elfcomm.exp
@@ -144,7 +144,7 @@ proc stt_common_test { options testname } {
     global READELF
     global ld
 
-    set options "$options tmpdir/common1a.o"
+    set options "$options tmpdir/common1c.o"
 
     if { ! [ld_simple_link $ld tmpdir/common.exe $options] } {
       unresolved $testname
@@ -154,7 +154,7 @@ proc stt_common_test { options testname } {
     send_log "$READELF --syms tmpdir/common.exe | grep foo\n"
     set exec_output [run_host_cmd "$READELF" "--syms tmpdir/common.exe | grep foo"]
 
-    if {![regexp "(\[ 	\]*)(\[0-9\]+):(\[ 	\]*)(\[0-9\]+)(\[ 	\]+)(\[0-9\]+)(\[ 	\]+)COMMON(\[ 	\]+)GLOBAL(\[ 	\]+)DEFAULT(\[ 	\]+)(\[0-9\]+)(\[ 	\]+)_?foo2" $exec_output] } {
+    if {![regexp { +[0-9a-f]+. +[0-9a-f]+ OBJECT + GLOBAL +DEFAULT +[0-9]+ _?foo2} $exec_output] } {
 	fail $testname
 	return 0
     }
@@ -163,23 +163,6 @@ proc stt_common_test { options testname } {
     return 1
 }
 
-# Check to see if the assembler is generating symbols with the STT_COMMON type.
-proc assembler_generates_commons {} {
-    global exec_output
-    global READELF
-
-    verbose "Check to see if STT_COMMON symbols are being generated:"
-    set exec_output [run_host_cmd "$READELF" "--syms tmpdir/common1a.o | grep foo"]
-
-    if { ![regexp "(\[ 	\]*)(\[0-9\]+):(\[ 	\]*)(\[0\]*)80(\[ 	\]+).(\[ 	\]+)COMMON(\[ 	\]+)GLOBAL(\[ 	\]+)DEFAULT(\[ 	\]+)(PRC\\\[0xff03\\\]|COM|SCOM)(\[ 	\]+)_?foo2" $exec_output] } {
-	verbose "STT_COMMON not generated"
-	return 0
-    }
-
-    verbose "STT_COMMON's are generated"
-    return 1
-}
-
 if [istarget nios2*-*-*] {
     set CFLAGS "$CFLAGS -G0"
 }
@@ -187,7 +170,9 @@ if [istarget nios2*-*-*] {
 # Explicitly use "-fcommon" so that even if $CFLAGS includes
 # "-fno-common", these tests are compiled as expected.
 if {   ![ld_compile "$CC $CFLAGS -fcommon" $srcdir/$subdir/common1a.c tmpdir/common1a.o]
-    || ![ld_compile "$CC $CFLAGS -fcommon" $srcdir/$subdir/common1b.c tmpdir/common1b.o] } {
+    || ![ld_compile "$CC $CFLAGS -fcommon" $srcdir/$subdir/common1b.c tmpdir/common1b.o]
+    || ![ld_compile "$CC $CFLAGS -Wa,--elf-stt-common=yes -fcommon" $srcdir/$subdir/common1b.c tmpdir/common1c.o] } {
+    unresolved $test1
     unresolved $test1
     return
 }
@@ -261,12 +246,56 @@ if { [dump_common1 $test1c2] } {
 #
 # The following tests are for when we are generating STT_COMMON symbols only.
 #
-
-if { ![assembler_generates_commons] } {
-    return
-}
-
 stt_common_test "-static -e 0" "static link of common symbols"
 stt_common_test "-shared"      "shared link of common symbols"
 stt_common_test "-pie"         "position independent link of common symbols"
 
+run_ld_link_tests [list \
+  [list \
+    "Build common-3x.o" \
+     "-r" "" "--elf-stt-common=no" \
+     {common-1.s} {} "common-3x.o" \
+  ] \
+  [list \
+    "Build common-3y.o" \
+     "-r" "" "--elf-stt-common=yes" \
+     {common-1.s} {} "common-3y.o" \
+  ] \
+  [list \
+    "Build common-3a.o" \
+    "-r tmpdir/common-3x.o tmpdir/common-3y.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3a.rd}} "common-3a.o" \
+  ] \
+  [list \
+    "Build common-3b.o" \
+    "-r tmpdir/common-3y.o tmpdir/common-3x.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3b.rd}} "common-3b.o" \
+  ] \
+  [list \
+    "Build common-3c.o" \
+    "-r -z nocommon tmpdir/common-3x.o tmpdir/common-3y.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3a.rd}} "common-3c.o" \
+  ] \
+  [list \
+    "Build common-3d.o" \
+    "-r -z common tmpdir/common-3x.o tmpdir/common-3y.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3b.rd}} "common-3b.o" \
+  ] \
+  [list \
+    "Build common-3e.o" \
+    "-r -z common tmpdir/common-3y.o tmpdir/common-3x.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3b.rd}} "common-3e.o" \
+  ] \
+  [list \
+    "Build common-3f.o" \
+    "-r -z nocommon tmpdir/common-3y.o tmpdir/common-3x.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3a.rd}} "common-3f.o" \
+  ] \
+]
+
+set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
+foreach t $test_list {
+    # We need to strip the ".d", but can leave the dirname.
+    verbose [file rootname $t]
+    run_dump_test [file rootname $t]
+}