Hi David,
As discussed, I have updated the to use SYMBOL-$ syntax for
PC-relative addressing and to use a new symbol, __gcc_unwind_dbase,
rather than overloading __dso_handle.
Regards,
Andrew
2014-09-09 Andrew Dixie <andr...@gentrack.com>
Move exception tables to read-only memory on AIX.
* collect2.c (write_c_file_stat): Provide dbase on AIX.
(scan_prog_file): Don't output __dso_handle nor __gcc_unwind_dbase.
* config/rs6000/aix.h (ASM_PREFERRED_EH_DATA_FORMAT): define.
(EH_TABLES_CAN_BE_READ_ONLY): define.
(ASM_OUTPUT_DWARF_PCREL): define.
(ASM_OUTPUT_DWARF_DATAREL): define.
(EH_FRAME_IN_DATA_SECTION): undefine.
* config/rs6000/rs6000-aix.c: new file.
(rs6000_aix_asm_output_dwarf_pcrel): new function.
(rs6000_aix_asm_output_dwarf_datarel): new function.
* config/rs6000/rs6000.c (rs6000_xcoff_asm_init_sections): remove
assignment of exception_section.
* dwarf2asm.c (dw2_asm_output_encoded_addr_rtx): Add call to
ASM_OUTPUT_DWARF_DATAREL.
* dwarf2out.c (switch_to_eh_frame_section): Add call to
EMIT_COLLECT2_LABELS_FOR_EH_FRAMES.
diff -rupN orig/gcc-4.10-20140706/gcc/collect2.c
gcc-4.10-20140706/gcc/collect2.c
--- orig/gcc-4.10-20140706/gcc/collect2.c 2014-06-26
21:16:28.000000000 +1200
+++ gcc-4.10-20140706/gcc/collect2.c 2014-09-09 19:37:49.383271225 +1200
@@ -2101,12 +2110,23 @@ write_c_file_stat (FILE *stream, const c
fprintf (stream, " struct object *next;\n");
fprintf (stream, "};\n");
+ fprintf (stream, "extern void __register_frame_info_table_bases
(void *, struct object *, void *tbase, void *dbase);\n");
fprintf (stream, "extern void __register_frame_info_table (void
*, struct object *);\n");
fprintf (stream, "extern void *__deregister_frame_info (void *);\n");
+#ifdef TARGET_AIX_VERSION
+ fprintf (stream, "extern void *__gcc_unwind_dbase;\n");
+#endif
fprintf (stream, "static void reg_frame () {\n");
fprintf (stream, "\tstatic struct object ob;\n");
+#ifdef TARGET_AIX_VERSION
+ /* As per config/rs6000/rs6000-aix.c, we use __gcc_unwind_dbase
as the dbase on AIX.
+ This might not be the start of the segment, we assume signed offsets.
+ */
+ fprintf (stream, "\t__register_frame_info_table_bases
(frame_table, &ob, (void *)0, &__gcc_unwind_dbase);\n");
+#else
fprintf (stream, "\t__register_frame_info_table (frame_table, &ob);\n");
+#endif
fprintf (stream, "\t}\n");
fprintf (stream, "static void dereg_frame () {\n");
@@ -2868,7 +2888,16 @@ scan_prog_file (const char *prog_name, s
provides an explicit export list. */
if (shared_obj && !is_shared
&& which_pass == PASS_OBJ && !export_flag)
- add_to_list (&exports, name);
+ {
+ /* Do not auto-export __dso_handle
or __gcc_unwind_dbase.
+ They are required to be local
to each module.
+ */
+ if (strcmp(name, "__dso_handle") != 0
+ && strcmp(name,
"__gcc_unwind_dbase") != 0)
+ {
+ add_to_list (&exports, name);
+ }
+ }
#endif
continue;
}
diff -rupN orig/gcc-4.10-20140706/gcc/config/rs6000/aix61.h
gcc-4.10-20140706/gcc/config/rs6000/aix61.h
--- orig/gcc-4.10-20140706/gcc/config/rs6000/aix61.h 2014-01-03
11:23:26.000000000 +1300
+++ gcc-4.10-20140706/gcc/config/rs6000/aix61.h 2014-09-10
17:52:02.125993022 +1200
@@ -167,7 +167,7 @@ do {
\
%{!maix64:\
%{pthread:%{pg:gcrt0_r%O%s}%{!pg:%{p:mcrt0_r%O%s}%{!p:crt0_r%O%s}}}\
%{!pthread:%{pg:gcrt0%O%s}%{!pg:%{p:mcrt0%O%s}%{!p:crt0%O%s}}}}}\
- %{shared:crtcxa_s%O%s;:crtcxa%O%s}"
+ %{shared:crtcxa_s%O%s;:crtcxa%O%s} crtdbase%O%s"
/* AIX V5 typedefs ptrdiff_t as "long" while earlier releases used "int". */
diff -rupN orig/gcc-4.10-20140706/gcc/config/rs6000/rs6000-aix.c
gcc-4.10-20140706/gcc/config/rs6000/rs6000-aix.c
--- orig/gcc-4.10-20140706/gcc/config/rs6000/rs6000-aix.c
1970-01-01 12:00:00.000000000 +1200
+++ gcc-4.10-20140706/gcc/config/rs6000/rs6000-aix.c 2014-09-09
19:39:34.770296080 +1200
@@ -0,0 +1,48 @@
+/* Functions for AIX on PowerPC.
+ Copyright (C) 2014 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC 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, or (at your option)
+any later version.
+
+GCC 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 GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "output.h"
+
+/* Overide the default 'SYMBOL-.' syntax with AIX compatible 'SYMBOL-$'. */
+void rs6000_asm_output_dwarf_pcrel(FILE *file, int size, const char *label)
+{
+ fputs (integer_asm_op (size, FALSE), file);
+ assemble_name (file, label);
+ fputs ("-$", file);
+}
+
+/* Output a symbol offset relative to the dbase for the current object.
+ We use __gcc_unwind_dbase as an arbitrary base for dbase and
assume signed offsets.
+
+ __gcc_unwind_dbase is embedded in all executables/libraries through
+ libgcc/config/rs6000/crtdbase.S
+ */
+void rs6000_asm_output_dwarf_datarel(FILE *file, int size, const char *label)
+{
+ fputs (integer_asm_op (size, FALSE), file);
+ assemble_name (file, label);
+ fputs("-__gcc_unwind_dbase", file);
+}
+
diff -rupN orig/gcc-4.10-20140706/gcc/config/rs6000/rs6000.c
gcc-4.10-20140706/gcc/config/rs6000/rs6000.c
--- orig/gcc-4.10-20140706/gcc/config/rs6000/rs6000.c 2014-07-03
18:13:48.000000000 +1200
+++ gcc-4.10-20140706/gcc/config/rs6000/rs6000.c 2014-07-25
13:43:54.151118199 +1200
@@ -29251,7 +29251,6 @@ rs6000_xcoff_asm_init_sections (void)
= get_unnamed_section (0, rs6000_xcoff_output_toc_section_asm_op, NULL);
readonly_data_section = read_only_data_section;
- exception_section = data_section;
}
static int
diff -rupN orig/gcc-4.10-20140706/gcc/config/rs6000/rs6000-protos.h
gcc-4.10-20140706/gcc/config/rs6000/rs6000-protos.h
--- orig/gcc-4.10-20140706/gcc/config/rs6000/rs6000-protos.h
2014-06-26 02:46:08.000000000 +1200
+++ gcc-4.10-20140706/gcc/config/rs6000/rs6000-protos.h 2014-07-28
12:41:54.852926208 +1200
@@ -195,6 +195,8 @@ extern void rs6000_aix_asm_output_dwarf_
extern void get_ppc476_thunk_name (char name[32]);
extern bool rs6000_overloaded_builtin_p (enum rs6000_builtins);
extern HOST_WIDE_INT rs6000_builtin_mask_calculate (void);
+extern void rs6000_asm_output_dwarf_pcrel(FILE *file, int size, const
char *label);
+extern void rs6000_asm_output_dwarf_datarel(FILE *file, int size,
const char *label);
/* Declare functions in rs6000-c.c */
diff -rupN orig/gcc-4.10-20140706/gcc/config/rs6000/t-aix52
gcc-4.10-20140706/gcc/config/rs6000/t-aix52
--- orig/gcc-4.10-20140706/gcc/config/rs6000/t-aix52 2014-01-03
11:23:26.000000000 +1300
+++ gcc-4.10-20140706/gcc/config/rs6000/t-aix52 2014-07-25
13:43:54.151118199 +1200
@@ -24,3 +24,7 @@ MULTILIB_OPTIONS = pthread maix64
MULTILIB_DIRNAMES = pthread ppc64
MULTILIB_MATCHES =
+
+rs6000-aix.o: $(srcdir)/config/rs6000/rs6000-aix.c
+ $(COMPILE) $<
+ $(POSTCOMPILE)
diff -rupN orig/gcc-4.10-20140706/gcc/config/rs6000/xcoff.h
gcc-4.10-20140706/gcc/config/rs6000/xcoff.h
--- orig/gcc-4.10-20140706/gcc/config/rs6000/xcoff.h 2014-06-26
02:46:08.000000000 +1200
+++ gcc-4.10-20140706/gcc/config/rs6000/xcoff.h 2014-07-28
12:48:43.361071782 +1200
@@ -299,8 +299,25 @@
#define DATA_SECTION_ASM_OP \
"\t.csect .data[RW]," XCOFF_CSECT_DEFAULT_ALIGNMENT_STR
+/* The eh_frames are put in the read-only text segment.
+ Local code labels/function will also be in the local text segment so use
+ PC relative addressing.
+ Global symbols must be in the data segment to allow loader relocations.
+ So use DW_EH_PE_indirect to allocate a slot in the local data segment.
+ There is no constant offset to this data segment from the text segment,
+ so use addressing relative to the data segment.
+ */
+#define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL) \
+ ((GLOBAL) ? (DW_EH_PE_indirect | DW_EH_PE_datarel |
DW_EH_PE_sdata4) : (DW_EH_PE_pcrel | DW_EH_PE_sdata4))
-/* Define to prevent DWARF2 unwind info in the data section rather
- than in the .eh_frame section. We do this because the AIX linker
- would otherwise garbage collect these sections. */
-#define EH_FRAME_IN_DATA_SECTION 1
+#define EMIT_COLLECT2_LABELS_FOR_EH_FRAMES 1
+
+#define TARGET_TERMINATE_DW2_EH_FRAME_INFO true
+
+#define EH_TABLES_CAN_BE_READ_ONLY 1
+
+#define ASM_OUTPUT_DWARF_PCREL(FILE, SIZE, LABEL) \
+ rs6000_asm_output_dwarf_pcrel(FILE, SIZE, LABEL);
+
+#define ASM_OUTPUT_DWARF_DATAREL(FILE, SIZE, LABEL) \
+ rs6000_asm_output_dwarf_datarel(FILE, SIZE, LABEL);
diff -rupN orig/gcc-4.10-20140706/gcc/config.gcc
gcc-4.10-20140706/gcc/config.gcc
--- orig/gcc-4.10-20140706/gcc/config.gcc 2014-07-04
19:18:19.000000000 +1200
+++ gcc-4.10-20140706/gcc/config.gcc 2014-07-29 12:46:11.459162754 +1200
@@ -2369,6 +2369,7 @@ rs6000-ibm-aix5.1.* | powerpc-ibm-aix5.1
rs6000-ibm-aix5.2.* | powerpc-ibm-aix5.2.*)
tm_file="${tm_file} rs6000/aix.h rs6000/aix52.h rs6000/xcoff.h
rs6000/aix-stdint.h"
tmake_file="rs6000/t-aix52 t-slibgcc"
+ extra_objs="$extra_objs rs6000-aix.o"
extra_options="${extra_options} rs6000/aix64.opt"
use_collect2=yes
thread_file='aix'
@@ -2378,6 +2379,7 @@ rs6000-ibm-aix5.2.* | powerpc-ibm-aix5.2
rs6000-ibm-aix5.3.* | powerpc-ibm-aix5.3.*)
tm_file="${tm_file} rs6000/aix.h rs6000/aix53.h rs6000/xcoff.h
rs6000/aix-stdint.h"
tmake_file="rs6000/t-aix52 t-slibgcc"
+ extra_objs="$extra_objs rs6000-aix.o"
extra_options="${extra_options} rs6000/aix64.opt"
use_collect2=yes
thread_file='aix'
@@ -2387,6 +2389,7 @@ rs6000-ibm-aix5.3.* | powerpc-ibm-aix5.3
rs6000-ibm-aix[6789].* | powerpc-ibm-aix[6789].*)
tm_file="${tm_file} rs6000/aix.h rs6000/aix61.h rs6000/xcoff.h
rs6000/aix-stdint.h"
tmake_file="rs6000/t-aix52 t-slibgcc"
+ extra_objs="$extra_objs rs6000-aix.o"
extra_options="${extra_options} rs6000/aix64.opt"
use_collect2=yes
thread_file='aix'
diff -rupN orig/gcc-4.10-20140706/gcc/doc/tm.texi.in
gcc-4.10-20140706/gcc/doc/tm.texi.in
--- orig/gcc-4.10-20140706/gcc/doc/tm.texi.in 2014-06-06
13:04:22.000000000 +1200
+++ gcc-4.10-20140706/gcc/doc/tm.texi.in 2014-07-28
12:41:54.852926208 +1200
@@ -6525,6 +6525,15 @@ Do not define this macro unless @code{TA
also defined.
@end defmac
+@defmac EMIT_COLLECT2_LABELS_FOR_EH_FRAMES
+If defined, gcc will output specially named labels for DWARF 2 frame unwind
+information, and collect2 will detect these labels and emit code to register
+the frames at runtime.
+
+If not defined, the target must register frame unwind tables
+through another mechanism.
+@end defmac
+
@defmac EH_TABLES_CAN_BE_READ_ONLY
Define this macro to 1 if your target is such that no frame unwind
information encoding used with non-PIC code will ever require a
@@ -7067,6 +7076,11 @@ A C statement to issue assembly directiv
reference to the given @var{label}, using an integer of the given @var{size}.
@end defmac
+@defmac ASM_OUTPUT_DWARF_DATAREL (@var{stream}, @var{size}, @var{label})
+A C statement to issue assembly directives that create a reference to the
+given @var{label} relative to the dbase, using an integer of the
given @var{size}.
+@end defmac
+
@defmac ASM_OUTPUT_DWARF_TABLE_REF (@var{label})
A C statement to issue assembly directives that create a reference to
the DWARF table identifier @var{label} from the current section. This
diff -rupN orig/gcc-4.10-20140706/gcc/dwarf2asm.c
gcc-4.10-20140706/gcc/dwarf2asm.c
--- orig/gcc-4.10-20140706/gcc/dwarf2asm.c 2014-01-03
11:23:26.000000000 +1300
+++ gcc-4.10-20140706/gcc/dwarf2asm.c 2014-07-25 14:07:57.050230529 +1200
@@ -992,6 +992,13 @@ dw2_asm_output_encoded_addr_rtx (int enc
dw2_assemble_integer (size, addr);
break;
+#ifdef ASM_OUTPUT_DWARF_DATAREL
+ case DW_EH_PE_datarel:
+ gcc_assert (GET_CODE (addr) == SYMBOL_REF);
+ ASM_OUTPUT_DWARF_DATAREL (asm_out_file, size, XSTR (addr, 0));
+ break;
+#endif
+
case DW_EH_PE_pcrel:
gcc_assert (GET_CODE (addr) == SYMBOL_REF);
#ifdef ASM_OUTPUT_DWARF_PCREL
diff -rupN orig/gcc-4.10-20140706/gcc/dwarf2out.c
gcc-4.10-20140706/gcc/dwarf2out.c
--- orig/gcc-4.10-20140706/gcc/dwarf2out.c 2014-07-02
09:35:41.000000000 +1200
+++ gcc-4.10-20140706/gcc/dwarf2out.c 2014-07-28 12:48:12.925359014 +1200
@@ -424,6 +424,11 @@ static void
switch_to_eh_frame_section (bool back)
{
tree label;
+#ifdef EMIT_COLLECT2_LABELS_FOR_EH_FRAMES
+ bool emit_collect2_labels = EMIT_COLLECT2_LABELS_FOR_EH_FRAMES;
+#else
+ bool emit_collect2_labels = true;
+#endif
#ifdef EH_FRAME_SECTION_NAME
if (eh_frame_section == 0)
@@ -464,7 +469,11 @@ switch_to_eh_frame_section (bool back)
/* We have no special eh_frame section. Put the information in
the data section and emit special labels to guide collect2. */
switch_to_section (data_section);
+ emit_collect2_labels = true;
+ }
+ if (emit_collect2_labels)
+ {
if (!back)
{
label = get_file_function_name ("F");
@@ -929,6 +938,9 @@ output_call_frame_info (int for_eh)
augmentation, any_lsda_needed, lsda_encoding);
}
+ if (!targetm.terminate_dw2_eh_frame_info) {
+ abort();
+ }
if (for_eh && targetm.terminate_dw2_eh_frame_info)
dw2_asm_output_data (4, 0, "End of Table");
diff -rupN orig/gcc-4.10-20140706/libgcc/config/rs6000/crtdbase.c
gcc-4.10-20140706/libgcc/config/rs6000/crtdbase.c
--- orig/gcc-4.10-20140706/libgcc/config/rs6000/crtdbase.c
1970-01-01 12:00:00.000000000 +1200
+++ gcc-4.10-20140706/libgcc/config/rs6000/crtdbase.c 2014-09-10
17:28:48.189945402 +1200
@@ -0,0 +1,26 @@
+/* Defines __gcc_unwind_dbase
+
+ Copyright (C) 2014 Free Software Foundation, Inc.
+
+ This file 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, or (at your option) any
+ later version.
+
+ This file 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.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+__asm__(".csect data[RW]\n__gcc_unwind_dbase:\n.globl __gcc_unwind_dbase");
+/* Zero length symbol used as an arbitrary base for offsets inside the data
+ * segment for unwind information. */
diff -rupN orig/gcc-4.10-20140706/libgcc/config/rs6000/t-aix-cxa
gcc-4.10-20140706/libgcc/config/rs6000/t-aix-cxa
--- orig/gcc-4.10-20140706/libgcc/config/rs6000/t-aix-cxa
2013-11-24 04:38:07.000000000 +1300
+++ gcc-4.10-20140706/libgcc/config/rs6000/t-aix-cxa 2014-09-10
16:36:16.850791121 +1200
@@ -5,6 +5,9 @@ LIB2ADD_ST += $(srcdir)/config/rs6000/ai
SHLIB_MAPFILES += $(srcdir)/config/rs6000/libgcc-aix-cxa.ver
+crtdbase.o: $(srcdir)/config/rs6000/crtdbase.c
+ $(crt_compile) -c $<
+
crtcxa.o: $(srcdir)/config/rs6000/crtcxa.c
$(crt_compile) -c $<
diff -rupN orig/gcc-4.10-20140706/libgcc/config.host
gcc-4.10-20140706/libgcc/config.host
--- orig/gcc-4.10-20140706/libgcc/config.host 2014-05-21
23:08:58.000000000 +1200
+++ gcc-4.10-20140706/libgcc/config.host 2014-09-09
19:33:58.321410780 +1200
@@ -1027,7 +1027,7 @@ rs6000-ibm-aix5.1.* | powerpc-ibm-aix5.1
rs6000-ibm-aix[56789].* | powerpc-ibm-aix[56789].*)
md_unwind_header=rs6000/aix-unwind.h
tmake_file="t-fdpbit rs6000/t-ppc64-fp rs6000/t-slibgcc-aix
rs6000/t-ibm-ldouble rs6000/t-aix-cxa"
- extra_parts="crtcxa.o crtcxa_s.o"
+ extra_parts="crtcxa.o crtcxa_s.o crtdbase.o"
;;
rl78-*-elf)
tmake_file="$tm_file t-fdpbit rl78/t-rl78"
