gas: improve C_BSTAT and C_STSYM symbols handling on XCOFF

A C_BSTAT debug symbol specifies the beginning of a static block.
Its n_value is the index of the csect containing static symbols.
A C_STSYM debug symbol represents the stabstring of a statically
allocated symbol. Its n_value is the offset in the csect pointed
by the containing C_BSTAT.

These two special n_value were not correctly handled both when
generating object files with gas or when reading them with objdump.
This patch tries to improve that and, above all, to allow gas-generated
object files with such symbols to be accepted by AIX ld.

bfd/
	* coff-bfd.c (bfd_coff_get_syment): Adjust n_value of symbols
	having fix_value = 1 in order to be an index and not a memory
	offset.
	* coffgen.c (coff_get_symbol_info): Likewize.
	(coff_print_symbol): Likewize.

gas/
	* config/tc-ppc.c (ppc_frob_label): Don't change within if
	already set.
	(ppc_stabx): Remove workaround changing exp.X_add_symbol's
	within.
	* config/tc-ppc.h (struct ppc_tc_sy): Update comments.
	* symbols.c (resolve_symbol_value): Remove symbol update
	when final_val is 0 and it's an AIX debug symbol.
	* testsuite/gas/ppc/aix.exp: Add new tests.
	* testsuite/gas/ppc/xcoff-stsym-32.d: New test.
	* testsuite/gas/ppc/xcoff-stsym-64.d: New test.
	* testsuite/gas/ppc/xcoff-stsym.s: New test.
This commit is contained in:
Clément Chigot 2021-07-27 14:37:50 +02:00
parent ad42014be2
commit cd026728f3
9 changed files with 90 additions and 8 deletions

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@ -45,8 +45,9 @@ bfd_coff_get_syment (bfd *abfd,
*psyment = csym->native->u.syment;
if (csym->native->fix_value)
psyment->n_value = psyment->n_value -
(bfd_hostptr_t) obj_raw_syments (abfd);
psyment->n_value =
((psyment->n_value - (bfd_hostptr_t) obj_raw_syments (abfd))
/ sizeof (combined_entry_type));
/* FIXME: We should handle fix_line here. */

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@ -2043,8 +2043,10 @@ coff_get_symbol_info (bfd *abfd, asymbol *symbol, symbol_info *ret)
if (coffsymbol (symbol)->native != NULL
&& coffsymbol (symbol)->native->fix_value
&& coffsymbol (symbol)->native->is_sym)
ret->value = coffsymbol (symbol)->native->u.syment.n_value -
(bfd_hostptr_t) obj_raw_syments (abfd);
ret->value =
((coffsymbol (symbol)->native->u.syment.n_value -
(bfd_hostptr_t) obj_raw_syments (abfd))
/ sizeof (combined_entry_type));
}
/* Print out information about COFF symbol. */
@ -2092,7 +2094,8 @@ coff_print_symbol (bfd *abfd,
if (! combined->fix_value)
val = (bfd_vma) combined->u.syment.n_value;
else
val = combined->u.syment.n_value - (bfd_hostptr_t) root;
val = ((combined->u.syment.n_value - (bfd_hostptr_t) root)
/ sizeof (combined_entry_type));
fprintf (file, "(sec %2d)(fl 0x%02x)(ty %3x)(scl %3d) (nx %d) 0x",
combined->u.syment.n_scnum,

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@ -2901,7 +2901,12 @@ ppc_frob_label (symbolS *sym)
symbol_remove (sym, &symbol_rootP, &symbol_lastP);
symbol_append (sym, symbol_get_tc (ppc_current_csect)->within,
&symbol_rootP, &symbol_lastP);
/* Update last csect symbol. */
symbol_get_tc (ppc_current_csect)->within = sym;
/* Some labels like .bs are using within differently.
So avoid changing it, if it's already set. */
if (symbol_get_tc (sym)->within == NULL)
symbol_get_tc (sym)->within = ppc_current_csect;
}
#endif
@ -5056,7 +5061,6 @@ ppc_stabx (int ignore ATTRIBUTE_UNUSED)
as_bad (_(".stabx of storage class stsym must be within .bs/.es"));
symbol_get_tc (sym)->within = ppc_current_block;
symbol_get_tc (exp.X_add_symbol)->within = ppc_current_block;
}
}

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@ -130,6 +130,7 @@ struct ppc_tc_sy
/* For a csect symbol, the last symbol which has been defined in
this csect, or NULL if none have been defined so far.
For a .bs symbol, the referenced csect symbol.
For a C_STSYM symbol, the containing block (.bs symbol).
For a label, the enclosing csect. */
symbolS *within;
union

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@ -1380,7 +1380,17 @@ resolve_symbol_value (symbolS *symp)
&& add_symbol->flags.resolving)
break;
if (finalize_syms && final_val == 0)
if (finalize_syms && final_val == 0
#ifdef OBJ_XCOFF
/* Avoid changing symp's "within" when dealing with
AIX debug symbols. For some storage classes, "within"
have a special meaning.
C_DWARF should behave like on Linux, thus this check
isn't done to be closer. */
&& ((symbol_get_bfdsym (symp)->flags & BSF_DEBUGGING) == 0
|| (S_GET_STORAGE_CLASS (symp) == C_DWARF))
#endif
)
{
if (add_symbol->flags.local_symbol)
add_symbol = local_symbol_convert (add_symbol);

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@ -81,4 +81,7 @@ if { [istarget "powerpc*-*-aix*"] || [istarget "rs6000-*-aix*"] } then {
run_dump_test "xcoff-tlsm-32"
run_dump_test "xcoff-tlsm-64"
run_dump_test "xcoff-stsym-32"
run_dump_test "xcoff-stsym-64"
}

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@ -0,0 +1,22 @@
#as: -a32
#source: xcoff-stsym.s
#objdump: -t
#name: XCOFF C_STSYM test (32-bit)
.*
SYMBOL TABLE:
.*
.*
.*
.*
\[ 4\]\(sec 1\).*\(scl 143\) \(nx 0\) 0x0000000a .bs
\[ 5\]\(sec -2\).*\(scl 133\) \(nx 0\) 0x00000000 x:V6
\[ 6\]\(sec 1\).*\(scl 144\) \(nx 0\) 0x00000000 .es
\[ 7\]\(sec 1\).*\(scl 143\) \(nx 0\) 0x0000000a .bs
\[ 8\]\(sec -2\).*\(scl 133\) \(nx 0\) 0x00000004 y:V6
\[ 9\]\(sec 1\).*\(scl 144\) \(nx 0\) 0x00000000 .es
\[ 10\].* _main\.rw_
.*

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@ -0,0 +1,22 @@
#as: -a64
#source: xcoff-stsym.s
#objdump: -t
#name: XCOFF C_STSYM test (64-bit)
.*
SYMBOL TABLE:
.*
.*
.*
.*
\[ 4\]\(sec 1\).*\(scl 143\) \(nx 0\) 0x000000000000000a .bs
\[ 5\]\(sec -2\).*\(scl 133\) \(nx 0\) 0x0000000000000000 x:V6
\[ 6\]\(sec 1\).*\(scl 144\) \(nx 0\) 0x0000000000000000 .es
\[ 7\]\(sec 1\).*\(scl 143\) \(nx 0\) 0x000000000000000a .bs
\[ 8\]\(sec -2\).*\(scl 133\) \(nx 0\) 0x0000000000000004 y:V6
\[ 9\]\(sec 1\).*\(scl 144\) \(nx 0\) 0x0000000000000000 .es
\[ 10\].* _main\.rw_
.*

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@ -0,0 +1,16 @@
.file "main.c"
.csect _main.rw_[RW],4
.csect .text[PR]
.bs _main.rw_[RW]
.stabx "x:V6",x.2,133,0
.es
.bs _main.rw_[RW]
.stabx "y:V6",y.1,133,0
.es
.csect _main.rw_[RW],4
x.2:
.long 100
y.1:
.long 110