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5ff6a06c21
Fix a functional regression with the `.end' pseudo-op, introduced with
commit ecb4347adecd ("Last take: approval for MIPS_STABS_ELF killing"),
<https://sourceware.org/ml/binutils/2002-06/msg00443.html>, and commit
dcd410fe1544 ("GNU as 2.14 on IRIX 6: crashes with shared libs"),
<https://sourceware.org/ml/binutils/2003-07/msg00415.html>, which caused
symbol values for labels placed between the end of a function's contents
and its terminating `.end' followed by one of the alignment pseudo-ops
to be different depending on whether either `-mdebug', or `-mno-pdr', or
neither of the command-line options is in effect, be it implied or
specified.
Given debug-label-end.s as follows and the `mips-linux' target we have:
$ cat debug-label-end.s
.text
.globl foo
.globl bar
.align 4, 0
.ent foo
foo:
nop
.aent bar
bar:
.insn
.end foo
.align 4, 0
.space 16
.globl baz
.ent baz
baz:
nop
.end baz
.align 4, 0
.space 16
$ as -o debug-label-end.o debug-label-end.s
$ readelf -s debug-label-end.o | grep bar
9: 00000004 0 FUNC GLOBAL DEFAULT 1 bar
$ as -mdebug -o debug-label-end.o debug-label-end.s
$ readelf -s debug-label-end.o | grep bar
9: 00000010 0 FUNC GLOBAL DEFAULT 1 bar
$ as -mno-pdr -o debug-label-end.o debug-label-end.s
$ readelf -s debug-label-end.o | grep bar
8: 00000010 0 FUNC GLOBAL DEFAULT 1 bar
$
The reason is the call to `md_flush_pending_output', which in the case
of `mips*-*-*' targets expands to `mips_emit_delays', which in turn
calls `mips_no_prev_insn', which calls `mips_clear_insn_labels', which
clears the list of outstanding labels. That list is in turn consulted
in `mips_align', called in the interpretation of alignment directives,
and the labels adjusted to the current location.
A call to `md_flush_pending_output' is only made from `s_mips_end' and
then only if `-mpdr' is in effect, which is the default for `*-*-linux*'
and some other `mips*-*-*' targets. A call to `md_flush_pending_output'
is never made from `ecoff_directive_end', which is used in place of
`s_mips_end' when `-mdebug' is in effect. Consequently if `-mno-pdr' or
`-mdebug' is in effect the list of outstanding labels makes it through
to any alignment directive that follows and the labels are differently
interpreted depending on the command-lines options used. And we want
code produced to be always the same.
Call `md_flush_pending_output' unconditionally then in `s_mips_end' and
add such a call from `ecoff_directive_end' as well, as long as the macro
is defined. While `ecoff_directive_end' is shared among targets, the
only one other than `mips*-*-*' actually using it is `alpha*-*-*' and it
does not define `md_flush_pending_output'. So the semantics isn't going
to change for it and neither it has to have its `s_alpha_end' updated
or have code in `ecoff_directive_end' conditionalized.
gas/
* ecoff.c (ecoff_directive_end) [md_flush_pending_output]: Call
`md_flush_pending_output'.
* config/tc-mips.c (s_mips_end) [md_flush_pending_output]: Call
`md_flush_pending_output' unconditionally.
* testsuite/gas/mips/debug-label-end-1.d: New test.
* testsuite/gas/mips/debug-label-end-2.d: New test.
* testsuite/gas/mips/debug-label-end-3.d: New test.
* testsuite/gas/mips/debug-label-end.s: New test source.
* testsuite/gas/mips/mips.exp: Run the new tests.
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