RFC: Add AIX .ref support
Richard Sandiford
rdsandiford@googlemail.com
Thu Jan 14 19:42:00 GMT 2010
This patch adds .ref support for AIX, to be compatible with the
native assembler. I didn't go ahead and install it because of the
potentially-contentious change to gas/write.c.
.ref adds a R_REF relocation to the beginning of the current csect,
a bit like an ELF ".reloc ...,R_FOO_NONE". However, the difficulty
is that relocations must be sorted in section order, so it isn't
appropriate to add a fixup at frag offset 0 after a fixup at frag
offset 4 (say).
Fortunately, we're always adding fixups at the beginning of a frag.
All we need is a version of fix_new that adds the new fixup to the head
of the list rather than the tail. And the code to do that is already
there, protected by the now-defunct REVERSE_SORT_RELOCS macro. So I
simply made it a C test and provided a wrapper function.
I suppose in a way this is just me being lazy. Perhaps a more robust
fix would be to make the XCOFF port sort relocations before writing
them out. This would make general .relocs work, for example.
Unfortunately, I don't have enough experience of other old formats
(a.out, other flavours of COFF) to know where the code should go.
I'm also not sure which (if any) formats support ELF-like relocation
chains, which would make it wrong to sort relocations against
overlapping fields.
Tested on powerpc-ibm-aix6.1.
Richard
bfd/
* coff-rs6000.c (xcoff_howto_table): Change size to 0 and bitsize to 1.
(_bfd_xcoff_reloc_type_lookup): Handle BFD_RELOC_NONE.
* coff64-rs6000.c (xcoff64_howto_table): Change size to 0 and
bitsize to 1.
(xcoff64_reloc_type_lookup): Handle BFD_RELOC_NONE.
gas/
* write.h (fix_at_start): Declare.
* write.c (fix_new_internal): Add at_beginning parameter.
Use it instead of REVERSE_SORT_RELOCS. Fix the handling of
seg_fix_tailP for the at_beginning/REVERSE_SORT_RELOCS case.
(fix_new, fix_new_exp): Update accordingly.
(fix_at_start): New function.
* config/tc-ppc.c (md_pseudo_table): Add .ref to the OBJ_XCOFF section.
(ppc_ref): New function, for OBJ_XCOFF.
(md_apply_fix): Handle BFD_RELOC_NONE for OBJ_XCOFF.
* config/te-i386aix.h (REVERSE_SORT_RELOCS): Remove #undef.
gas/testsuite/
* gas/ppc/xcoff-ref-1.s, gas/ppc/xcoff-ref-1.l: New test.
* gas/ppc/aix.exp: Run it.
ld/testsuite/
* ld-powerpc/aix-ref-1-32.od, ld-powerpc/aix-ref-1-64.od,
ld-powerpc/aix-ref-1.s: New tests.
* ld-powerpc/aix52.exp: Run them.
Index: bfd/coff-rs6000.c
===================================================================
--- bfd/coff-rs6000.c 2010-01-14 19:18:18.000000000 +0000
+++ bfd/coff-rs6000.c 2010-01-14 19:18:30.000000000 +0000
@@ -896,11 +896,11 @@ reloc_howto_type xcoff_howto_table[] =
EMPTY_HOWTO (0xe),
- /* Non-relocating reference. */
+ /* Non-relocating reference. Bitsize is 1 so that r_rsize is 0. */
HOWTO (R_REF, /* type */
0, /* rightshift */
- 2, /* size (0 = byte, 1 = short, 2 = long) */
- 32, /* bitsize */
+ 0, /* size (0 = byte, 1 = short, 2 = long) */
+ 1, /* bitsize */
FALSE, /* pc_relative */
0, /* bitpos */
complain_overflow_dont, /* complain_on_overflow */
@@ -1162,6 +1162,8 @@ _bfd_xcoff_reloc_type_lookup (abfd, code
case BFD_RELOC_32:
case BFD_RELOC_CTOR:
return &xcoff_howto_table[0];
+ case BFD_RELOC_NONE:
+ return &xcoff_howto_table[0xf];
default:
return NULL;
}
Index: bfd/coff64-rs6000.c
===================================================================
--- bfd/coff64-rs6000.c 2010-01-14 19:18:18.000000000 +0000
+++ bfd/coff64-rs6000.c 2010-01-14 19:18:31.000000000 +0000
@@ -1594,11 +1594,11 @@ reloc_howto_type xcoff64_howto_table[] =
EMPTY_HOWTO (0xe),
- /* Non-relocating reference. */
+ /* Non-relocating reference. Bitsize is 1 so that r_rsize is 0. */
HOWTO (R_REF, /* type */
0, /* rightshift */
- 2, /* size (0 = byte, 1 = short, 2 = long) */
- 32, /* bitsize */
+ 0, /* size (0 = byte, 1 = short, 2 = long) */
+ 1, /* bitsize */
FALSE, /* pc_relative */
0, /* bitpos */
complain_overflow_dont, /* complain_on_overflow */
@@ -1882,6 +1882,8 @@ xcoff64_reloc_type_lookup (abfd, code)
return &xcoff64_howto_table[0x1c];
case BFD_RELOC_64:
return &xcoff64_howto_table[0];
+ case BFD_RELOC_NONE:
+ return &xcoff64_howto_table[0xf];
default:
return NULL;
}
Index: gas/write.h
===================================================================
--- gas/write.h 2010-01-14 19:18:18.000000000 +0000
+++ gas/write.h 2010-01-14 19:18:31.000000000 +0000
@@ -176,6 +176,9 @@ extern void number_to_chars_bigendian (c
extern fixS *fix_new
(fragS * frag, int where, int size, symbolS * add_symbol,
offsetT offset, int pcrel, bfd_reloc_code_real_type r_type);
+extern fixS *fix_at_start
+ (fragS * frag, int size, symbolS * add_symbol,
+ offsetT offset, int pcrel, bfd_reloc_code_real_type r_type);
extern fixS *fix_new_exp
(fragS * frag, int where, int size, expressionS *exp, int pcrel,
bfd_reloc_code_real_type r_type);
Index: gas/write.c
===================================================================
--- gas/write.c 2010-01-14 19:18:18.000000000 +0000
+++ gas/write.c 2010-01-14 19:27:17.000000000 +0000
@@ -150,7 +150,8 @@ fix_new_internal (fragS *frag, /* Which
symbolS *sub_symbol, /* X_op_symbol. */
offsetT offset, /* X_add_number. */
int pcrel, /* TRUE if PC-relative relocation. */
- RELOC_ENUM r_type ATTRIBUTE_UNUSED /* Relocation type. */)
+ RELOC_ENUM r_type ATTRIBUTE_UNUSED /* Relocation type. */,
+ int at_beginning) /* Add to the start of the list? */
{
fixS *fixP;
@@ -194,10 +195,6 @@ fix_new_internal (fragS *frag, /* Which
as_where (&fixP->fx_file, &fixP->fx_line);
- /* Usually, we want relocs sorted numerically, but while
- comparing to older versions of gas that have relocs
- reverse sorted, it is convenient to have this compile
- time option. xoxorich. */
{
fixS **seg_fix_rootP = (frags_chained
@@ -207,22 +204,22 @@ fix_new_internal (fragS *frag, /* Which
? &seg_info (now_seg)->fix_tail
: &frchain_now->fix_tail);
-#ifdef REVERSE_SORT_RELOCS
-
- fixP->fx_next = *seg_fix_rootP;
- *seg_fix_rootP = fixP;
-
-#else /* REVERSE_SORT_RELOCS */
-
- fixP->fx_next = NULL;
-
- if (*seg_fix_tailP)
- (*seg_fix_tailP)->fx_next = fixP;
+ if (at_beginning)
+ {
+ fixP->fx_next = *seg_fix_rootP;
+ *seg_fix_rootP = fixP;
+ if (fixP->fx_next == NULL)
+ *seg_fix_tailP = fixP;
+ }
else
- *seg_fix_rootP = fixP;
- *seg_fix_tailP = fixP;
-
-#endif /* REVERSE_SORT_RELOCS */
+ {
+ fixP->fx_next = NULL;
+ if (*seg_fix_tailP)
+ (*seg_fix_tailP)->fx_next = fixP;
+ else
+ *seg_fix_rootP = fixP;
+ *seg_fix_tailP = fixP;
+ }
}
return fixP;
@@ -240,7 +237,7 @@ fix_new (fragS *frag, /* Which frag? *
RELOC_ENUM r_type /* Relocation type. */)
{
return fix_new_internal (frag, where, size, add_symbol,
- (symbolS *) NULL, offset, pcrel, r_type);
+ (symbolS *) NULL, offset, pcrel, r_type, FALSE);
}
/* Create a fixup for an expression. Currently we only support fixups
@@ -308,7 +305,19 @@ fix_new_exp (fragS *frag, /* Which frag
break;
}
- return fix_new_internal (frag, where, size, add, sub, off, pcrel, r_type);
+ return fix_new_internal (frag, where, size, add, sub, off, pcrel,
+ r_type, FALSE);
+}
+
+/* Create a fixup at the beginning of FRAG. The arguments are the same
+ as for fix_new, except that WHERE is implicitly 0. */
+
+fixS *
+fix_at_start (fragS *frag, int size, symbolS *add_symbol,
+ offsetT offset, int pcrel, RELOC_ENUM r_type)
+{
+ return fix_new_internal (frag, 0, size, add_symbol,
+ (symbolS *) NULL, offset, pcrel, r_type, TRUE);
}
/* Generic function to determine whether a fixup requires a relocation. */
Index: gas/config/tc-ppc.c
===================================================================
--- gas/config/tc-ppc.c 2010-01-14 19:18:18.000000000 +0000
+++ gas/config/tc-ppc.c 2010-01-14 19:22:40.000000000 +0000
@@ -108,6 +108,7 @@ static void ppc_change_csect (symbolS *,
static void ppc_function (int);
static void ppc_extern (int);
static void ppc_lglobl (int);
+static void ppc_ref (int);
static void ppc_section (int);
static void ppc_named_section (int);
static void ppc_stabx (int);
@@ -212,6 +213,7 @@ const pseudo_typeS md_pseudo_table[] =
{ "extern", ppc_extern, 0 },
{ "function", ppc_function, 0 },
{ "lglobl", ppc_lglobl, 0 },
+ { "ref", ppc_ref, 0 },
{ "rename", ppc_rename, 0 },
{ "section", ppc_named_section, 0 },
{ "stabx", ppc_stabx, 0 },
@@ -3559,6 +3561,58 @@ ppc_lglobl (int ignore ATTRIBUTE_UNUSED)
demand_empty_rest_of_line ();
}
+/* The .ref pseudo-op. It takes a list of symbol names and inserts R_REF
+ relocations at the beginning of the current csect.
+
+ (In principle, there's no reason why the relocations _have_ to be at
+ the beginning. Anywhere in the csect would do. However, inserting
+ at the beginning is what the native assmebler does, and it helps to
+ deal with cases where the .ref statements follow the section contents.)
+
+ ??? .refs don't work for empty .csects. However, the native assembler
+ doesn't report an error in this case, and neither yet do we. */
+
+static void
+ppc_ref (int ignore ATTRIBUTE_UNUSED)
+{
+ char *name;
+ char c;
+
+ if (ppc_current_csect == NULL)
+ {
+ as_bad (_(".ref outside .csect"));
+ ignore_rest_of_line ();
+ return;
+ }
+
+ do
+ {
+ name = input_line_pointer;
+ c = get_symbol_end ();
+
+ fix_at_start (symbol_get_frag (ppc_current_csect), 0,
+ symbol_find_or_make (name), 0, FALSE, BFD_RELOC_NONE);
+
+ *input_line_pointer = c;
+ SKIP_WHITESPACE ();
+ c = *input_line_pointer;
+ if (c == ',')
+ {
+ input_line_pointer++;
+ SKIP_WHITESPACE ();
+ if (is_end_of_line[(unsigned char) *input_line_pointer])
+ {
+ as_bad (_("missing symbol name"));
+ ignore_rest_of_line ();
+ return;
+ }
+ }
+ }
+ while (c == ',');
+
+ demand_empty_rest_of_line ();
+}
+
/* The .rename pseudo-op. The RS/6000 assembler can rename symbols,
although I don't know why it bothers. */
@@ -6032,6 +6086,11 @@ md_apply_fix (fixS *fixP, valueT *valP,
PPC_HA (value), 2);
break;
+#ifdef OBJ_XCOFF
+ case BFD_RELOC_NONE:
+ break;
+#endif
+
#ifdef OBJ_ELF
case BFD_RELOC_PPC64_HIGHER:
if (fixP->fx_pcrel)
Index: gas/config/te-i386aix.h
===================================================================
--- gas/config/te-i386aix.h 2010-01-14 19:18:18.000000000 +0000
+++ gas/config/te-i386aix.h 2010-01-14 19:18:31.000000000 +0000
@@ -24,10 +24,6 @@ #define TE_I386AIX 1
#include "obj-format.h"
-/* Undefine REVERSE_SORT_RELOCS to keep the relocation entries sorted
- in ascending vaddr. */
-#undef REVERSE_SORT_RELOCS
-
/* Define KEEP_RELOC_INFO so that the strip reloc info flag F_RELFLG is
not used in the filehdr for COFF output. */
#define KEEP_RELOC_INFO
Index: gas/testsuite/gas/ppc/xcoff-ref-1.s
===================================================================
--- /dev/null 2010-01-14 19:00:33.502131340 +0000
+++ gas/testsuite/gas/ppc/xcoff-ref-1.s 2010-01-14 19:18:31.000000000 +0000
@@ -0,0 +1,6 @@
+ .ref foo
+ .csect bar[rw]
+ .ref 1234
+ .ref a,
+ .ref ,
+ .ref
Index: gas/testsuite/gas/ppc/xcoff-ref-1.l
===================================================================
--- /dev/null 2010-01-14 19:00:33.502131340 +0000
+++ gas/testsuite/gas/ppc/xcoff-ref-1.l 2010-01-14 19:18:31.000000000 +0000
@@ -0,0 +1,5 @@
+.*: Assembler messages:
+.*:1: Error: .ref outside .csect
+.*:3: Error: junk at end of line, first unrecognized character is `1'
+.*:4: Error: missing symbol name
+.*:5: Error: missing symbol name
Index: gas/testsuite/gas/ppc/aix.exp
===================================================================
--- gas/testsuite/gas/ppc/aix.exp 2010-01-14 19:18:18.000000000 +0000
+++ gas/testsuite/gas/ppc/aix.exp 2010-01-14 19:18:31.000000000 +0000
@@ -65,4 +65,6 @@ if [istarget powerpc-ibm-aix*] then {
run_dump_test "textalign-xcoff-002"
run_dump_test "xcoff-branch-1-32"
run_dump_test "xcoff-branch-1-64"
+
+ run_list_test "xcoff-ref-1"
}
Index: ld/testsuite/ld-powerpc/aix-ref-1-32.od
===================================================================
--- /dev/null 2010-01-14 19:00:33.502131340 +0000
+++ ld/testsuite/ld-powerpc/aix-ref-1-32.od 2010-01-14 19:18:31.000000000 +0000
@@ -0,0 +1,30 @@
+
+.*
+
+
+Disassembly of section \.text:
+
+.* <foo1>:
+.*: 60 00 00 00 oril r0,r0,0
+ .*: R_REF foo2\+.*
+.*: 80 22 00 00 l r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+.*: 4e 80 00 20 br
+
+.* <foo2>:
+.*: 60 00 00 00 oril r0,r0,0
+ .*: R_REF foo6\+.*
+ .*: R_REF foo4\+.*
+.*: 80 22 00 00 l r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+
+.* <foo4>:
+.*: 60 00 00 00 oril r0,r0,0
+.*: 80 22 00 00 l r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+
+.* <foo6>:
+.*: 60 00 00 00 oril r0,r0,0
+.*: 80 22 00 00 l r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+ \.\.\.
Index: ld/testsuite/ld-powerpc/aix-ref-1-64.od
===================================================================
--- /dev/null 2010-01-14 19:00:33.502131340 +0000
+++ ld/testsuite/ld-powerpc/aix-ref-1-64.od 2010-01-14 19:18:31.000000000 +0000
@@ -0,0 +1,30 @@
+
+.*
+
+
+Disassembly of section \.text:
+
+.* <foo1>:
+ .*: 60 00 00 00 nop
+ .*: R_REF foo2\+.*
+ .*: e8 22 00 00 ld r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+ .*: 4e 80 00 20 blr
+
+.* <foo2>:
+ .*: 60 00 00 00 nop
+ .*: R_REF foo6\+.*
+ .*: R_REF foo4\+.*
+ .*: e8 22 00 00 ld r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+
+.* <foo4>:
+ .*: 60 00 00 00 nop
+ .*: e8 22 00 00 ld r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+
+.* <foo6>:
+ .*: 60 00 00 00 nop
+ .*: e8 22 00 00 ld r1,0\(r2\)
+ .*: R_TOC stuff\+.*
+ \.\.\.
Index: ld/testsuite/ld-powerpc/aix-ref-1.s
===================================================================
--- /dev/null 2010-01-14 19:00:33.502131340 +0000
+++ ld/testsuite/ld-powerpc/aix-ref-1.s 2010-01-14 19:18:31.000000000 +0000
@@ -0,0 +1,57 @@
+ .macro loadtoc,sym
+ .if size == 32
+ lwz 1,\sym(2)
+ .else
+ ld 1,\sym(2)
+ .endif
+ .endm
+
+ .toc
+LC01: .tc stuff[TC],stuff[RW]
+
+ .globl foo1
+ .csect foo1[pr]
+foo1:
+ .align 8
+ nop
+ loadtoc LC01
+
+ .globl foo2
+ .csect foo2[pr]
+foo2:
+ nop
+ loadtoc LC01
+ .ref foo4 , foo6
+
+ .globl foo3
+ .csect foo3[pr]
+foo3:
+ nop
+ loadtoc LC01
+
+ .globl foo4
+ .csect foo4[pr]
+foo4:
+ nop
+ loadtoc LC01
+
+ .globl foo5
+ .csect foo5[pr]
+foo5:
+ nop
+ loadtoc LC01
+ .ref foo3
+
+ .globl foo6
+ .csect foo6[pr]
+foo6:
+ nop
+ loadtoc LC01
+
+ .csect foo1[pr]
+ blr
+ .ref foo2
+
+ .csect stuff[rw]
+stuff:
+ .long 1
Index: ld/testsuite/ld-powerpc/aix52.exp
===================================================================
--- ld/testsuite/ld-powerpc/aix52.exp 2010-01-14 19:18:19.000000000 +0000
+++ ld/testsuite/ld-powerpc/aix52.exp 2010-01-14 19:18:31.000000000 +0000
@@ -196,6 +196,11 @@ set aix52tests {
"" {aix-rel-1.s}
{{objdump -hr aix-rel-1.od}} "aix-rel-1.ro"}
+ {".ref test 1" "-efoo1"
+ "" {aix-ref-1.s}
+ {{objdump -dr aix-ref-1-SIZE.od}}
+ "aix-ref-1"}
+
{"Weak test 1 (rel)" "-r"
"" {aix-weak-1a.s aix-weak-1b.s}
{{nm {} aix-weak-1-rel.nd} {objdump -h aix-weak-1-rel.hd}}
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