[3/21] Keep .text, .data and .bss on AIX

[Richard Sandiford <richards at transitive dot com>]

We currently strip empty output sections on AIX, just like we do on ELF.
However, the AIX loader complains if a shared library contains no .text,
.data or .bss section (that is, if the SNtext, SNdata and SNbss fields
are 0 rather than valid section indices).

This patch makes sure we keep these three sections.  OK to install?

Richard


ld/
	* emultempl/aix.em (gld${EMULATION_NAME}_before_allocation): Mark
	.text, .data and .bss output sections as SEC_KEEP.

ld/testsuite/
	* ld-powerpc/aix-core-sec-1.s, ld-powerpc/aix-core-sec-1.ex,
	ld-powerpc/aix-core-sec-1.hd, ld-powerpc/aix-core-sec-2.s,
	ld-powerpc/aix-core-sec-2.ex, ld-powerpc/aix-core-sec-2.hd,
	ld-powerpc/aix-core-sec-3.s, ld-powerpc/aix-core-sec-3.ex,
	ld-powerpc/aix-core-sec-3.hd: New tests.
	* ld-powerpc/aix52.exp: New harness.

Index: ld/emultempl/aix.em
===================================================================
--- ld/emultempl/aix.em	2009-03-10 13:38:53.000000000 +0000
+++ ld/emultempl/aix.em	2009-03-10 13:43:04.000000000 +0000
@@ -616,7 +616,12 @@ gld${EMULATION_NAME}_before_allocation (
   struct export_symbol_list *el;
   char *libpath;
   asection *special_sections[XCOFF_NUMBER_OF_SPECIAL_SECTIONS];
-  int i;
+  static const char *const must_keep_sections[] = {
+    ".text",
+    ".data",
+    ".bss"
+  };
+  unsigned int i;
 
   /* Handle the import and export files, if any.  */
   for (fl = import_files; fl != NULL; fl = fl->next)
@@ -824,6 +829,19 @@ gld${EMULATION_NAME}_before_allocation (
 	}
     }
 
+  /* We must always have .text, .data and .bss output sections, so that
+     the header can refer to them.  The kernel refuses to load shared
+     objects that have missing sections.  */
+  for (i = 0; i < ARRAY_SIZE (must_keep_sections); i++)
+    {
+      asection *sec;
+
+      sec = bfd_get_section_by_name (link_info.output_bfd,
+				     must_keep_sections[i]);
+      if (sec)
+	sec->flags |= SEC_KEEP;
+    }
+
   before_allocation_default ();
 }
 
Index: ld/testsuite/ld-powerpc/aix-core-sec-1.s
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-1.s	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,5 @@
+	.globl	foo
+	.csect	foo[RO]
+foo:
+	.long	0x12345678
+	.long	0xdeadbeef
Index: ld/testsuite/ld-powerpc/aix-core-sec-1.ex
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-1.ex	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,1 @@
+foo
Index: ld/testsuite/ld-powerpc/aix-core-sec-1.hd
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-1.hd	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,11 @@
+#...
+Sections:
+.*
+ * 0 * \.text * 0+8 .*
+ * CONTENTS, ALLOC, LOAD, CODE
+ * 1 * \.data * 0+0 .*
+ * ALLOC, LOAD, DATA
+ * 2 * \.bss * 0+0 .*
+ * ALLOC
+ * 3 * \.loader .*
+ * CONTENTS, ALLOC, LOAD
Index: ld/testsuite/ld-powerpc/aix-core-sec-2.s
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-2.s	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,5 @@
+	.globl	foo
+	.csect	foo[RW]
+foo:
+	.long	0x12345678
+	.long	0xdeadbeef
Index: ld/testsuite/ld-powerpc/aix-core-sec-2.ex
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-2.ex	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,1 @@
+foo
Index: ld/testsuite/ld-powerpc/aix-core-sec-2.hd
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-2.hd	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,11 @@
+#...
+Sections:
+.*
+ * 0 * \.text * 0+0 .*
+ * ALLOC, LOAD, CODE
+ * 1 * \.data * 0+8 .*
+ * CONTENTS, ALLOC, LOAD, DATA
+ * 2 * \.bss * 0+0 .*
+ * ALLOC
+ * 3 * \.loader .*
+ * CONTENTS, ALLOC, LOAD
Index: ld/testsuite/ld-powerpc/aix-core-sec-3.s
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-3.s	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,1 @@
+	.comm	foo,8
Index: ld/testsuite/ld-powerpc/aix-core-sec-3.ex
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-3.ex	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,1 @@
+foo
Index: ld/testsuite/ld-powerpc/aix-core-sec-3.hd
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-core-sec-3.hd	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,11 @@
+#...
+Sections:
+.*
+ * 0 * \.text * 0+0 .*
+ * ALLOC, LOAD, CODE
+ * 1 * \.data * 0+0 .*
+ * ALLOC, LOAD, DATA
+ * 2 * \.bss * 0+8 .*
+ * ALLOC
+ * 3 * \.loader .*
+ * CONTENTS, ALLOC, LOAD
Index: ld/testsuite/ld-powerpc/aix52.exp
===================================================================
--- /dev/null	2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix52.exp	2009-03-10 13:43:04.000000000 +0000
@@ -0,0 +1,89 @@
+# Expect script for AIX 5.2+ tests
+#   Copyright 2009 Free Software Foundation
+#
+# 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.
+#
+
+if { ![istarget "powerpc*-*-aix\[5-9\]*"]
+     || [istarget "powerpc*-*-aix5.\[01\]*"] } {
+    return
+}
+
+# Run a run_link_tests-style test for AIX.  SIZE selects the target size
+# (32 or 64).  The other arguments are elements of a run_link_tests test.
+#
+# Make the following changes before running the test:
+#
+#    - Mention SIZE in the test name.
+#    - Add "-aSIZE --defsym size=SIZE" to the assembler options.
+#    - Add the source directory to any "-bI:" and "-bE:" linker options.
+#    - Add "-bSIZE" to the linker options.
+#    - Add "-XSIZE" to the archiver options.
+#    - Replace "SIZE" with SIZE in TOOLS.
+#    - When testing 64-bit targets:
+#      - Turn tmpdir/aix-* into tmpdir/aix64-*.
+#      - Turn tmpdir/libaix-* into tmpdir/libaix64-*.
+#      - Turn -laix* into -laix64*, to compensate for the above.
+proc run_aix_test { size name ldopts asopts sources tools output } {
+    global srcdir subdir
+
+    if { $size == 64 } {
+	regsub -all {tmpdir/aix-} $ldopts {tmpdir/aix64-} ldopts
+	regsub {^aix} $output {aix64} output
+
+	regsub -all -- {-laix-} $ldopts {-laix64-} ldopts
+	regsub {^libaix} $output {libaix64} output
+    }
+    if { [regexp {.a$} $output] } {
+	append ldopts " -X$size"
+    } else {
+	regsub -all {(-b[IE]):} $ldopts "\\1:$srcdir/$subdir/" ldopts
+	append ldopts " -b$size"
+    }
+    regsub -all {SIZE} $tools $size tools
+    run_ld_link_tests [list [list "$name ($size-bit)" \
+				 $ldopts \
+				 "$asopts -a$size --defsym size=$size" \
+				 $sources \
+				 $tools \
+				 $output]]
+}
+
+set aix52tests {
+    {"Core sections test 1" "-shared -bE:aix-core-sec-1.ex"
+     "" {aix-core-sec-1.s}
+     {{objdump -h aix-core-sec-1.hd}}
+     "aix-core-sec-1.so"}
+
+    {"Core sections test 2" "-shared -bE:aix-core-sec-2.ex"
+     "" {aix-core-sec-2.s}
+     {{objdump -h aix-core-sec-2.hd}}
+     "aix-core-sec-2.so"}
+
+    {"Core sections test 3" "-shared -bE:aix-core-sec-3.ex"
+     "" {aix-core-sec-3.s}
+     {{objdump -h aix-core-sec-3.hd}}
+     "aix-core-sec-3.so"}
+}
+
+foreach test $aix52tests {
+    foreach { name ldopts asopts sources tools output } $test {
+	run_aix_test 32 $name $ldopts $asopts $sources $tools $output
+	run_aix_test 64 $name $ldopts $asopts $sources $tools $output
+    }
+}