The following generic warning message, which is printed whenever the
assembler skips generation of SFrame FDE, is not very helpful for the
user:
skipping SFrame FDE; CFI insn <name> (0x<hexval>)
Whenever possible print meaningful warning messages, when the assembler
skips generation of SFrame FDE:
- skipping SFrame FDE; non-SP/FP register <regno> in .cfi_def_cfa
- skipping SFrame FDE; non-SP/FP register <regno> in
.cfi_def_cfa_register
- skipping SFrame FDE; .cfi_def_cfa_offset without CFA base register
in effect
- skipping SFrame FDE; {FP|RA} register <regno> in .cfi_val_offset
- skipping SFrame FDE; {SP|FP|RA} register <regno> in in .cfi_register
- skipping SFrame FDE; .cfi_remember_state without prior SFrame FRE
state
- skipping SFrame FDE; non-default RA register <regno>
gas/
* gen-sframe.h (SFRAME_FRE_BASE_REG_INVAL): New macro for
invalid SFrame FRE CFA base register value of -1.
* gen-sframe.c: User readable warnings if SFrame FDE is not
generated.
gas/testsuite/
* gas/cfi-sframe/common-empty-1.d: Update generic SFrame test
case to updated warning message texts.
* gas/cfi-sframe/common-empty-2.d: Likewise.
* gas/cfi-sframe/common-empty-3.d: Likewise.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Adds two new external authors to etc/update-copyright.py to cover
bfd/ax_tls.m4, and adds gprofng to dirs handled automatically, then
updates copyright messages as follows:
1) Update cgen/utils.scm emitted copyrights.
2) Run "etc/update-copyright.py --this-year" with an extra external
author I haven't committed, 'Kalray SA.', to cover gas testsuite
files (which should have their copyright message removed).
3) Build with --enable-maintainer-mode --enable-cgen-maint=yes.
4) Check out */po/*.pot which we don't update frequently.
The newer update-copyright.py fixes file encoding too, removing cr/lf
on binutils/bfdtest2.c and ld/testsuite/ld-cygwin/exe-export.exp, and
embedded cr in binutils/testsuite/binutils-all/ar.exp string match.
Gather the information from the DWARF FDE on whether frame's return
addresses are signed using the B key or A key. Reflect the information in
the SFrame counterpart data structure, the SFrame FDE.
ChangeLog:
* gas/gen-sframe.c (get_dw_fde_pauth_b_key_p): New definition.
(sframe_v1_set_func_info): Add new argument for pauth_key.
(sframe_set_func_info): Likewise.
(output_sframe_funcdesc): Likewise.
* gas/gen-sframe.h (struct sframe_version_ops): Add new argument
to the function pointer declaration.
* gas/sframe-opt.c (sframe_convert_frag): Handle pauth_key.
DW_CFA_AARCH64_negate_ra_state in aarch64 is multiplexed with
DW_CFA_GNU_window_save in the DWARF format.
Remove the common-empty-4 testcase because the generated SFrame section
will not be be empty anymore. A relevant test will be added in a later
commit.
ChangeLog:
* gas/gen-sframe.c (sframe_v1_set_fre_info): Add new argument
for mangled_ra_p.
(sframe_set_fre_info): Likewise.
(output_sframe_row_entry): Handle mangled_ra_p.
(sframe_row_entry_new): Reset mangled_ra_p.
(sframe_row_entry_initialize): Initialize mangled_ra_p.
(sframe_xlate_do_gnu_window_save): New definition.
(sframe_do_cfi_insn): Handle DW_CFA_GNU_window_save.
* gas/gen-sframe.h (struct sframe_row_entry): New member.
(struct sframe_version_ops): Add a new argument for
mangled_ra_p.
* gas/testsuite/gas/cfi-sframe/cfi-sframe.exp: Remove test.
* gas/testsuite/gas/cfi-sframe/common-empty-4.d: Removed.
* gas/testsuite/gas/cfi-sframe/common-empty-4.s: Removed.
Currently supported for x86_64 and aarch64 only.
[PS: Currently, the compiler has not been adapted to generate
".cfi_sections" with ".sframe" in it. The newly added command line
option of --gsframe provides an easy way to try out .sframe support
in the toolchain.]
gas interprets the CFI directives to generate DWARF-based .eh_frame
info. These internal DWARF structures are now consumed by
gen-sframe.[ch] sub-system to, in turn, create the SFrame unwind
information. These internal DWARF structures are read-only for the
purpose of SFrame unwind info generation.
SFrame unwind info generation does not impact .eh_frame unwind info
generation. Both .eh_frame and .sframe can co-exist in an ELF file,
if so desired by the user.
Recall that SFrame unwind information only contains the minimal
necessary information to generate backtraces and does not provide
information to recover all callee-saved registers. The reason being
that callee-saved registers other than FP are not needed for stack
unwinding, and hence are not included in the .sframe section.
Consequently, gen-sframe.[ch] only needs to interpret a subset of
DWARF opcodes in gas. More details follow.
[Set 1, Interpreted] The following opcodes are interpreted:
- DW_CFA_advance_loc
- DW_CFA_def_cfa
- DW_CFA_def_cfa_register
- DW_CFA_def_cfa_offset
- DW_CFA_offset
- DW_CFA_remember_state
- DW_CFA_restore_state
- DW_CFA_restore
[Set 2, Bypassed] The following opcodes are acknowledged but are not
necessary for generating SFrame unwind info:
- DW_CFA_undefined
- DW_CFA_same_value
Anything else apart from the two above-mentioned sets is skipped
altogether. This means that any function containing a CFI directive not
in Set 1 or Set 2 above, will not have any SFrame unwind information
generated for them. Holes in instructions covered by FREs of a single
FDE are not representable in the SFrame unwind format.
As few examples, following opcodes are not processed for .sframe
generation, and are skipped:
- .cfi_personality*
- .cfi_*lsda
- .cfi_escape
- .cfi_negate_ra_state
- ...
Not processing .cfi_escape, .cfi_negate_ra_state will cause SFrame
unwind information to be absent for SFrame FDEs that contain these CFI
directives, hence affecting the asynchronicity.
x86-64 and aarch64 backends need to have a few new definitions and
functions for .sframe generation. These provide gas with architecture
specific information like the SP/FP/RA register numbers and an
SFrame-specific ABI marker.
Lastly, the patch also implements an optimization for size, where
specific fragments containing SFrame FRE start address and SFrame FDE
function are fixed up. This is similar to other similar optimizations
in gas, where fragments are sized and fixed up when the associated
symbols can be resolved. This optimization is controlled by a #define
SFRAME_FRE_TYPE_SELECTION_OPT and should be easy to turn off if needed.
The optimization is on by default for both x86_64 and aarch64.
ChangeLog:
* gas/Makefile.am: Include gen-sframe.c and sframe-opt.c.
* gas/Makefile.in: Regenerated.
* gas/as.h (enum _relax_state): Add new state rs_sframe.
(sframe_estimate_size_before_relax): New function.
(sframe_relax_frag): Likewise.
(sframe_convert_frag): Likewise.
* gas/config/tc-aarch64.c (aarch64_support_sframe_p): New
definition.
(aarch64_sframe_ra_tracking_p): Likewise.
(aarch64_sframe_cfa_ra_offset): Likewise.
(aarch64_sframe_get_abi_arch): Likewise.
(md_begin): Set values of sp/fp/ra registers.
* gas/config/tc-aarch64.h (aarch64_support_sframe_p): New
declaration.
(support_sframe_p): Likewise.
(SFRAME_CFA_SP_REG): Likewise.
(SFRAME_CFA_FP_REG): Likewise.
(SFRAME_CFA_RA_REG): Likewise.
(aarch64_sframe_ra_tracking_p): Likewise.
(sframe_ra_tracking_p): Likewise.
(aarch64_sframe_cfa_ra_offset): Likewise.
(sframe_cfa_ra_offset): Likewise.
(aarch64_sframe_get_abi_arch): Likewise.
(sframe_get_abi_arch): Likewise.
* gas/config/tc-i386.c (x86_support_sframe_p): New definition.
(x86_sframe_ra_tracking_p): Likewise.
(x86_sframe_cfa_ra_offset): Likewise.
(x86_sframe_get_abi_arch): Likewise.
* gas/config/tc-i386.h (x86_support_sframe_p): New declaration.
(support_sframe_p): Likewise.
(SFRAME_CFA_SP_REG): Likewise.
(SFRAME_CFA_FP_REG): Likewise.
(x86_sframe_ra_tracking_p): Likewise.
(sframe_ra_tracking_p): Likewise.
(x86_sframe_cfa_ra_offset): Likewise.
(sframe_cfa_ra_offset): Likewise.
(x86_sframe_get_abi_arch): Likewise.
(sframe_get_abi_arch): Likewise.
* gas/config/tc-xtensa.c (unrelaxed_frag_max_size): Add case for
rs_sframe.
* gas/doc/as.texi: Add .sframe to the documentation for
.cfi_sections.
* gas/dw2gencfi.c (cfi_finish): Create a .sframe section.
* gas/dw2gencfi.h (CFI_EMIT_sframe): New definition.
* gas/write.c (cvt_frag_to_fill): Handle rs_sframe.
(relax_segment): Likewise.
* gas/gen-sframe.c: New file.
* gas/gen-sframe.h: New file.
* gas/sframe-opt.c: New file.
