In DWARF CFI an "undefined" register rule for the return address (RA)
register indicates that there is no return address and the stack trace
is complete.
Represent DW_CFA_undefined as SFrame FRE without any offsets, so that a
stack tracer implementation can use this as indication that an outermost
frame has been reached and the stack trace is complete.
This representation is backward compatible, as existing stack tracers
should already deal with the case, that an SFrame FRE a so far invalid
offset count of zero and stop the trace.
include/
* sframe.h (SFRAME_V2_FRE_RA_UNDEFINED_P): New macro to test
FRE info word for RA undefined (FRE without any offsets).
binutils/
* NEWS: Mention SFrame can represent an undefined RA as FRE
without any offsets.
gas/
* gen-sframe.h (struct sframe_row_entry): Add ra_undefined_p
flag.
* gen-sframe.c (sframe_row_entry_new): Initialize ra_undefined_p
flag to not set.
(sframe_row_entry_initialize): Treat ra_undefined_p flag as
sticky.
(sframe_fre_set_ra_track): Reset ra_undefined_p flag.
(sframe_xlate_do_restore): Reset ra_undefined_p flag to saved
state.
(sframe_xlate_do_same_value): Reset ra_undefined_p flag.
(sframe_xlate_do_cfi_undefined): For RA set ra_undefined_p flag.
(output_sframe_row_entry): Represent RA undefined as SFrame FRE
without any offsets and FRE info word fields zeroed.
* NEWS: Mention assembler represents .cfi_undefined RA in SFrame
as FRE without any offsets.
libsframe/
* doc/sframe-spec.texi (Changes from Version 1 to Version 2):
Mention that a SFrame FRE without any offsets flag indicates an
outermost frame with an undefined RA.
(fre_offset_count): Document that a FRE offset count of zero
indicates an outermost frame with an undefined RA.
* sframe.c (sframe_get_fre_ra_undefined_p): Use macro
SFRAME_V2_FRE_RA_UNDEFINED_P.
(sframe_fre_get_fp_offset, sframe_fre_get_ra_offset): Do not
return fixed FP/RA offset if RA undefined.
* sframe-dump.c (dump_sframe_func_with_fres): Show FRE without
any offsets as "RA undefined".
gas/testsuite/
* gas/cfi-sframe/cfi-sframe.exp: Run tests for .cfi_undefined RA
on AArch64, s390x, and x86-64.
* gas/cfi-sframe/cfi-sframe-aarch64-ra-undefined-1.d: Add test
for .cfi_undefined RA on AArch64.
* gas/cfi-sframe/cfi-sframe-aarch64-ra-undefined-1.s: Likewise.
* as/cfi-sframe/cfi-sframe-s390x-ra-undefined-1.d: Add test
for .cfi_undefined RA on s390x.
* gas/cfi-sframe/cfi-sframe-s390x-ra-undefined-1.s: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-ra-undefined-1.d: Add test
for .cfi_undefined RA on x86-64.
* gas/cfi-sframe/cfi-sframe-x86_64-ra-undefined-1.s: Likewise.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Allow SFrame sections without any FREs, that can occur if they solely
contain FDEs without any FREs. For FDEs without and FREs set the
offset to the first FRE to zero.
libsframe/
* sframe.c (sframe_encoder_write_sframe): Allow SFrame sections
without any FREs. For FDEs without any FREs set the offset to
the first FRE to zero.
gas/
* gen-sframe.c (output_sframe_funcdesc): For FDEs without any
FREs set the offset to the first FRE to zero.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
There are many more places that copy an uninitialised expressionS to a
symbol via symbol_set_value_expression and make_expr_symbol. This
patch focuses on general gas code that does that, and a few backends.
Note that unlike the i386 case that oss-fuzz found, it is likely that
the tc-alpha.c, tc-ppc.c and tc-tic54x.c changes are not fixing bugs,
alpha and tic54x because they don't use X_md, ppc because it carefully
handles X_md. Also, as an example an O_constant expression should
only ever have its X_add_number field accessed, therefore the other
fields can stay uninitialised. However, I think that copying
uninitialised struct fields around is not good practice. If nothing
else it can be confusing when examining symbols under gdb.
I also replaced gen-sframe.c "#ifdef SFRAME_FRE_TYPE_SELECTION_OPT"
with "if (SFRAME_FRE_TYPE_SELECTION_OPT)" so code in the false
branches is compiled and thus less likely to bitrot. (As far as I can
see, SFRAME_FRE_TYPE_SELECTION_OPT is always 1.)
* cgen.c (expr_build_binary): Use structure initialiser to
ensure all fields of expression are initialised.
* config/obj-coff.c (obj_coff_val): Likewise.
* config/tc-alpha.c (add_to_link_pool): Likewise.
* config/tc-i386-intel.c (i386_intel_simplify): Likewise.
* config/tc-mips.c (fix_loongson2f_jump, load_register),
(load_address, add_got_offset, add_got_offset_hilo),
(macro_build_branch_likely, macro, mips16_macro),
(s_cpload, s_cpsetup, s_cprestore, s_cpreturn): Likewise.
* config/tc-ppc.c (ppc_function): Likewise.
* config/tc-tic54x.c (tic54x_field): Likewise.
* dw2gencfi.c (output_cfi_insn): Likewise.
* expr.c (expr_build_uconstant): Likewise.
* read.c (s_mri_common): Likewise.
* gen-sframe.c (create_fre_start_addr_exp),
(create_func_info_exp, output_sframe_row_entry): Likewise.
Don't conditionally compile via SFRAME_FRE_TYPE_SELECTION_OPT.
* cgen.c (gas_cgen_parse_operand): Use md_expr_init_rest.
* config/tc-microblaze.c (microblaze_s_weakext): Likewise.
* ecoff.c (ecoff_directive_weakext, ecoff_stab): Likewise.
* read.c (pseudo_set): Likewise.
Currently, gas warns and skips generating SFrame FDE when it sees:
.cfi_escape 0x2e,XX
From the documentation of DW_CFA_GNU_args_size:
"The DW_CFA_GNU_args_size instruction takes an unsigned LEB128 operand
representing an argument size. This instruction specifies the total of
the size of the arguments which have been pushed onto the stack."
With origins seemingly for VAX architecture, the usage of
DW_CFA_GNU_args_size seems to have evolved. The purpose of
DW_CFA_GNU_args_size is to adjust SP when performing stack unwinding for
exception handling.
For the purpose of stack tracing using SFrame, DW_CFA_GNU_args_size is
safe to skip, especially when the CFA restoration is known to be FP
based. A previous summary of the reasoning and intent was indicated
here [1].
[1] https://sourceware.org/pipermail/binutils/2025-August/143829.html
This fixes PR gas/33414 - sframe: handle DW_CFA_GNU_args_size in gas better
gas/
PR gas/33414
* gen-sframe.c (sframe_xlate_do_escape_gnu_args_size): New
definition.
(sframe_xlate_do_cfi_escape): Handle DW_CFA_GNU_args_size.
gas/testsuite/
PR gas/33414
* gas/cfi-sframe/cfi-sframe.exp: New test.
* gas/cfi-sframe/cfi-sframe-common-12.d: New test.
* gas/cfi-sframe/cfi-sframe-common-12.s: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-3.d: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-3.s: New test.
Use const pointers for function arguments and local vars where
applicable. 'cfi_insn' contains the DWARF CFI instruction data which,
for the purpose of SFrame generation, is read-only. Similarly, some
getter APIs and output related APIs now document their argument as
read-only.
While at it, also remove the ATTRIBUTE_UNUSED from argument xlate_ctx in
sframe_xlate_do_register () because the argument is indeed conditionally
used.
SFrame generation code assumes that since DW_CFA_restore means
restoration of the state of the register to the one at the beginning of
the function, there must be a state to restore to (hence the gas_assert
(cie_fre)).
This assumption needs adjustment. DW_CFA_restore may be present in the
very beginning of a (e.g., cold) function, with no initialized state for
SFrame functions to restore to.
gas/
PR gas/33170
* gas/gen-sframe.c (sframe_xlate_do_restore): Use current FRE if
CIE FRE is not yet setup.
gas/testsuite/
PR gas/33170
* gas/cfi-sframe/cfi-sframe.exp: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-pr33170.d: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-pr33170.s: New test.
In SFrame V2 the size of the offsets following an SFrame FRE can be
either signed 8-bit, 16-bit, or 32-bit integer, with the largest offset
determining their size:
1. CFA offset from CFA base register
2. RA (stack save slot) offset from CFA, usually -48 on s390x if saved
3. FP (stack save slot) offset from CFA, usually -72 on s390x if saved
The FP and RA offsets from CFA, when FP/RA saved on the stack, usually
have fixed values that fit into signed 8-bit SFrame offsets. Likewise
the DWARF register numbers on s390x of general registers (GR; 0-15) and
floating-point registers (FPR; 16-31), when FP/RA saved in registers.
With that the CFA offset from CFA base register has the greatest impact
on the signed SFrame offset size.
The s390x ELF ABI [1] defines the CFA as stack pointer (SP) at call
site +160. [2] Therefore the minimum CFA offset from CFA base register
on s390x is 160. This does not fit into a signed 8-bit integer and
therefore effectively prevents any use of signed 8-bit SFrame offsets
on s390x.
For s390x store the CFA offset from CFA base register adjusted by -160
to enable the use of signed 8-bit SFrame offsets.
[1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases
[2]: s390x ELF ABI, commit 4e38ad9c8a88 ("Document the CFA"),
https://github.com/IBM/s390x-abi/commit/4e38ad9c8a88
include/
* sframe.h (SFRAME_S390X_CFA_OFFSET_ADJUSTMENT): Define
s390x-specific CFA offset adjustment.
(SFRAME_V2_S390X_CFA_OFFSET_ENCODE,
SFRAME_V2_S390X_CFA_OFFSET_DECODE): New s390x-specific
macros. Use SFRAME_S390X_CFA_OFFSET_ADJUSTMENT to en-/decode
CFA offset.
bfd/
* elf64-s390.c (elf_s390x_sframe_plt_fre): Use
SFRAME_V2_S390X_CFA_OFFSET_ENCODE on CFA offset to store it
adjusted and switch to 8-bit offsets.
gas/
* gen-sframe.c (sframe_fre_set_cfa_offset): For s390x use
SFRAME_V2_S390X_CFA_OFFSET_ENCODE on CFA offset to store it
adjusted.
(sframe_fre_get_cfa_offset): New helper. For s390x use
SFRAME_V2_S390X_CFA_OFFSET_DECODE on CFA offset to undo its
adjustment.
(sframe_xlate_do_def_cfa_register): Use new helper
sframe_fre_get_cfa_offset.
libsframe/
* sframe.c (sframe_fre_get_cfa_offset): For s390x use
SFRAME_V2_S390X_CFA_OFFSET_DECODE on CFA offset to undo its
adjustment.
* doc/sframe-spec.texi (s390x,
SFRAME_S390X_CFA_OFFSET_ADJUSTMENT,
SFRAME_V2_S390X_CFA_OFFSET_ENCODE,
SFRAME_V2_S390X_CFA_OFFSET_DECODE): Document s390x-specific
adjustment of CFA offset.
libsframe/testsuite/
* libsframe.find/plt-findfre-2.c (add_plt0_fde, add_pltn_fde):
Use SFRAME_V2_S390X_CFA_OFFSET_ENCODE to enable use of 1-byte
SFrame offsets.
Suggested-by: Indu Bhagat <indu.bhagat@oracle.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
If an architecture uses both SFrame RA and FP tracking SFrame assumes
that the RA offset is the 2nd offset and the FP offset is the 3rd offset
following a SFrame FRE. An architecture does not necessarily need to
save both on the stack (or in register) at the same time or even at all.
SFrame cannot represent FP without RA saved on stack (or in a register),
since it cannot distinguish whether the 2nd offset is the RA or FP
offset.
For s390x use an invalid SFrame RA offset from CFA value of zero as
padding to represent the FP being saved when the RA is not saved. This
aligns with the existing invalid SFrame fixed RA offset from CFA value
of zero. In a stack tracer this then also naturally falls into place,
as it can skip restoring the RA in the topmost frame, if both the fixed
RA offset (from SFrame header) and the RA offset (from FDE) are zero,
without any need to test architecture-specific flags.
include/
* sframe.h (SFRAME_FRE_RA_OFFSET_INVALID): New define. Used as
padding offset.
* sframe-api.h (sframe_fre_get_ra_offset): Add comment that for
s390x an offset value of SFRAME_FRE_RA_OFFSET_INVALID indicates
that the RA is not saved.
gas/
* gen-sframe.c (get_fre_num_offsets): For s390x account padding
RA offset, if FP without RA saved.
(sframe_get_fre_offset_size): Likewise.
(output_sframe_row_entry): For s390x write a padding RA offset,
if FP without RA needs to be represented.
(sframe_do_fde): Enable FP without RA saved to be represented
on s390x.
libsframe/
* sframe.c (sframe_fre_get_ra_offset): Add comment that for
s390x an offset value of SFRAME_FRE_RA_OFFSET_INVALID indicates
that the RA is not saved.
* sframe-dump.c (dump_sframe_func_with_fres): Treat invalid
RA offsets as if they were undefined. Display them as "U"
to distinguish them.
* doc/sframe-spec.texi (s390x): Document s390x-specific use of
SFRAME_FRE_RA_OFFSET_INVALID to represent FP without RA saved.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe.exp: Rename s390x-specific tests.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.s: Rename
to ...
* cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-2.s: This.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-2.d: Likewise.
Update test verification pattern accordingly.
* cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.s: Rename
to ...
* cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-2.s: This.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-2.d: Likewise.
Update test verification pattern accordingly.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
GCC on s390x, when in a leaf function, can be observed to save the
frame pointer (FP) and/or return address (RA) register in a floating-
point registers (FPR) instead of on the stack. This is declared using
the following CFI directive:
.cfi_register <fp/ra-regnum>, <fpr-regnum>
SFrame cannot represent the FP and/or RA being saved in another
register. It does only track the CFA base register (SP/FP), CFA offset
from CFA base register, and FP and RA save area offsets from CFA.
On s390x the FP and/or RA are only saved in another FPR when in a leaf
function. That is a function that does not call any other function.
Therefore it can ever only be the topmost function in a call chain.
An unwinder by default has access to all registers of the function that
is the topmost on the call stack. Therefore no further information
is required to restore FP/RA from the FPR.
Represent FP/RA saved in another register on s390x, by encoding the
DWARF register number shifted by one to the left with the least-
significant bit set in the offset as follows:
offset = (regnum << 1) | 1
The use of the least-significant bit of the offset as indication is
possible, as the stack pointer (SP), the CFA, and any register save
area slots are 8-byte aligned according to the s390x ELF ABI:
- The stack pointer (SP) "shall maintain an 8-byte alignment". [1]
- The CFA is defined as SP at call site +160. [2]
- Pointers and 8-byte integers, such as general register values, must
be 8-byte aligned. [3]
SFrame FP and RA stack offsets must therefore always be a multiple of
8 on s390x. Note that for the same reason the DWARF data alignment
factor is -8 on s390x (see DWARF2_CIE_DATA_ALIGNMENT).
Add s390x-specific SFrame (error) tests for FP/RA saved in FPRs in leaf
function.
[1]: s390x ELF ABI, sections "Register Roles" and "Stack Frame
Allocation", https://github.com/IBM/s390x-abi/releases
[2]: s390x ELF ABI, commit 4e38ad9c8a88 ("Document the CFA"),
https://github.com/IBM/s390x-abi/commit/4e38ad9c8a88
[3]: s390x ELF ABI, section "Fundamental Types", table "Scalar types",
https://github.com/IBM/s390x-abi/releases
include/
* sframe.h (SFRAME_V2_S390X_OFFSET_IS_REGNUM): New s390x-
specific macro to test whether an SFrame FP/RA offset is a DWARF
register number.
(SFRAME_V2_S390X_OFFSET_ENCODE_REGNUM): New s390x-specific macro
to encode a DWARF register number into an SFrame FP/RA offset.
(SFRAME_V2_S390X_OFFSET_DECODE_REGNUM): New s390x-specific macro
to decode an SFrame FP/RA offset into a DWARF register number.
* sframe-api.h (sframe_fre_get_fp_offset,
sframe_fre_get_fp_offset): Add comment that for s390x the offset
may be an encoded register number.
gas/
* gen-sframe.c (s390_sframe_xlate_do_register): New S390-
specific function. Uses SFRAME_V2_S390X_OFFSET_ENCODE_REGNUM to
represent FP/RA saved in another register on s390x.
(sframe_xlate_do_register): Invoke s390_sframe_xlate_do_register
on s390x.
libsframe/
* sframe.c (sframe_fre_get_fp_offset, sframe_fre_get_fp_offset):
Add comment that for s390x the offset may be an encoded register
number.
* sframe-dump.c (is_sframe_abi_arch_s390x): New helper to test
whether ABI/arch is s390x.
(dump_sframe_func_with_fres): Use
SFRAME_V2_S390X_OFFSET_IS_REGNUM and
SFRAME_V2_S390X_OFFSET_DECODE_REGNUM to dump FP/RA saved in
another register on s390x.
* doc/sframe-spec.texi (s390x): Document s390x-specific
representation of FP/RA saved in another register.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe.exp: Update s390x-specific SFrame
(error) tests.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.s: Rename
to ...
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.d:
Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-1.s: This. Test
no longer triggers a warning, as SFrame can represent FP and RA
saved in registers.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.d: Test
now triggers a different warning, as SFrame can represent FP and
RA saved in registers, but not FP without RA saved in register.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
This introduces initial support to generate .sframe from CFI directives
in assembler on s390 64-bit (s390x). Due to SFrame V2 format
limitations it has the following limitations, some of them getting
addressed by subsequent patches, which cause generation of SFrame FDE
to be skipped:
- SFrame FP/RA tracking only supports register contents being saved on
the stack (i.e. .cfi_offset). It does not support FP/RA register
contents being saved in other registers (i.e. .cfi_register). GCC on
s390x can be observed to save the FP/RA register contents in floating-
point registers, but only in leaf functions.
This issue is detailed further and resolved in the subsequent commit
"s390: Represent FP/RA saved in register in SFrame".
- SFrame FP/RA tracking cannot represent FP without RA saved. This is
because the format assumes SFrame FDE offset2 to be the RA offset, if
there are two offsets, and offset3 to be the FP offset, if there are
three offsets. There is no mean to distinguish whether offset2 is the
RA or FP offset, if there are only two offsets.
This issue is detailed further and resolved in the subsequent commit
"s390: Represent FP without RA saved in SFrame".
- SFrame assumes a dedicated FP register number. The s390x ELF ABI [1]
does only designate register 11 as preferred FP register number. In
general GCC and Clang on s390x use register 11 as frame pointer.
GCC on s390x can be observed to use register 14 as frame pointer in
the stack clash protector in the function prologue.
glibc on s390x contains hand-written assembler code that uses
register 12 as frame pointer.
This s390x support is largely based on the AArch64 support from commit
b52c4ee466 ("gas: generate .sframe from CFI directives").
The SFrame ABI/arch identifier SFRAME_ABI_S390X_ENDIAN_BIG is introduced
for s390x and added to the SFrame format specification.
The s390x ELF ABI [1] specifies the following C calling conventions for
s390x architecture:
- Register 15 is the stack pointer (SP).
- Register 14 contains the return address (RA) at function entry.
- There is no dedicated frame pointer register. Register 11 is the
preferred frame pointer (FP). [2] GCC and Clang in general use
register 11 as frame pointer.
- The CFA is defined as SP at call site +160. [3] The SP at call site
can therefore be derived from the CFA using a SP value offset from CFA
of -160.
The s390x ELF ABI [1] does not assign any standard save slot to each
register in the register save area of a stack frame. Neither the
return address (RA, r14) nor preferred frame pointer (FP, r11)
necessarily need to be saved. Therefore SFrame RA and FP tracking is
used.
Support for SFrame on s390 is only enabled for the 64-bit s390x ELF ABI
(z/Architecture with 64-bit addressing mode). It is disabled for the
32-bit s390 ELF ABI (ESA/390 or z/Architecture with 32-bit addressing
mode).
s390x-specific SFrame assembler and linker tests are added, including
error tests for use of a non-preferred frame pointer (FP) register and
specification of a non-default return address (RA) register.
[1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases
[2]: s390x ELF ABI, commit f00421825979 ("Add information about the frame
pointer register"),
https://github.com/IBM/s390x-abi/commit/f00421825979
[3]: s390x ELF ABI, commit 4e38ad9c8a88 ("Document the CFA"),
https://github.com/IBM/s390x-abi/commit/4e38ad9c8a88
include/
* sframe.h: Add reference to s390x architecture in comments.
(SFRAME_ABI_S390X_ENDIAN_BIG): Define SFrame ABI/arch identifier
for s390x.
(SFRAME_S390X_SP_VAL_OFFSET): Define s390x-specific SP value
offset from CFA.
libsframe/
* sframe.c (need_swapping): Add SFRAME_ABI_S390X_ENDIAN_BIG.
* doc/sframe-spec.texi (SFRAME_ABI_S390X_ENDIAN_BIG, s390x,
SFRAME_S390X_SP_VAL_OFFSET): Document SFrame ABI/arch identifier
for s390x, add references to s390x architecture, and document
s390x-specifics, such as the SP value offset from CFA of -160.
gas/
* config/tc-s390.h: s390x support to generate .sframe from CFI
directives in assembler.
(support_sframe_p): Define.
(SFRAME_CFA_SP_REG, SFRAME_CFA_FP_REG, SFRAME_CFA_RA_REG):
Define.
(sframe_ra_tracking_p): Define.
(sframe_cfa_ra_offset): Define.
(sframe_get_abi_arch): Define.
* config/tc-s390.c: s390x support to generate .sframe from CFI
directives in assembler.
(s390_sframe_cfa_sp_reg, s390_sframe_cfa_fp_reg,
s390_sframe_cfa_ra_reg): New. Initialize to DWARF register
numbers of stack pointer (SP, r15), preferred frame pointer
(FP, r11), and return address (RA, r14) registers.
(s390_support_sframe_p): New function. Return true if s390x.
(s390_sframe_ra_tracking_p): New function. Return true.
(s390_sframe_cfa_ra_offset): New function. Return
SFRAME_CFA_FIXED_RA_INVALID.
(s390_sframe_get_abi_arch): New function. Return
SFRAME_ABI_S390X_ENDIAN_BIG if s390x, otherwise zero.
* gen-sframe.c: Add reference to s390x architecture in comments.
(sframe_xlate_do_val_offset): Add support for s390x-specific
SFRAME_S390X_SP_VAL_OFFSET.
* NEWS: Add news entry.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe.exp: Enable common SFrame tests for
s390x. Add s390x-specific SFrame (error) tests.
* gas/cfi-sframe/cfi-sframe-s390x-1.d: New s390x-specific SFrame
test.
* gas/cfi-sframe/cfi-sframe-s390x-1.s: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-2.s: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-err-1.d: New s390x-specific
SFrame error test that uses a non-default frame-pointer register
as CFA base register.
* gas/cfi-sframe/cfi-sframe-s390x-err-1.s: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-err-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-err-2.s: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-err-3.d: New s390x-specific
SFrame error test that uses a non-default return address
register.
* gas/cfi-sframe/cfi-sframe-s390x-err-3.s: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-1.d: New s390x-
specific SFrame test that saves RA and FP individually on the
stack.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-1.s: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.d: New
s390x-specific SFrame error test that saves FP and RA
individually, to trigger FP without RA saved.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.s: Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.d: New
s390x-specific SFrame error test that saves FP and RA
individually in registers.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.s:
Likewise.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.d: New
s390x-specific SFrame error test that saves RA and FP
individually in registers.
* gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.s:
Likewise.
ld/testsuite/
* ld-s390/s390.exp: Add simple SFrame test.
* ld-s390/sframe-simple-1.d: New simple SFrame test.
* ld-s390/sframe-bar.s: Likewise.
* ld-s390/sframe-foo.s: Likewise.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
for SFRAME_V2_GNU_AS_LD_ENCODING_FLAGS.
The intention of creating an abstraction like
SFRAME_V2_GNU_AS_LD_ENCODING_FLAGS is to address the concern that there
should be a central place to enforce harmonious flags between GNU as and
ld. At the moment, the only flag that needs to be enforced is
SFRAME_F_FDE_FUNC_START_PCREL.
sframe.h and sframe-api.h are installed headers by libsframe for the
specification and implementation respectively. Adding a definition like
SFRAME_V2_GNU_AS_LD_ENCODING_FLAGS does not fit in either. Create a
new internal header instead to keep the definition uncoupled from
sframe.h and sframe-api.h. Rename the previously added
SFRAME_F_LD_MUSTHAVE_FLAGS to define the new
SFRAME_V2_GNU_AS_LD_ENCODING_FLAGS.
bfd/
* elf-sframe.c (_bfd_elf_merge_section_sframe): Use the new
internal header and SFRAME_V2_GNU_AS_LD_ENCODING_FLAGS.
gas/
* gen-sframe.c (output_sframe_internal): Likewise.
include/
* sframe-api.h (SFRAME_F_LD_MUSTHAVE_FLAGS): Move from..
* sframe-internal.h: ..to here. New file.
Many frag_var calls have unnecessary casts on arguments, no doubt from
the days when binutils was written for K&R C. (ie. functions were not
prototyped so you needed to cast anything that didn't match the
expected type after default promotions, as you still do for args
matching a function ellipsis.) Remove those casts.
* config/tc-alpha.c (s_alpha_comm): Use offset_T for cur_size
to avoid need for casts. Remove casts from frag_var args.
* config/tc-ia64.c (obj_elf_vms_common): Remove casts from
frag_var args.
* config/tc-m32r.c (m32r_scomm): Likewise.
* config/tc-m68hc11.c (build_jump_insn): Likewise.
(build_dbranch_insn): Likewise.
* config/tc-m68k.c (md_assemble): Likewise.
* config/tc-microblaze.c (microblaze_s_lcomm): Likewise.
* config/tc-mmix.c (s_loc): Likewise.
* config/tc-ppc.c (ppc_elf_lcomm, ppc_comm): Likewise.
* config/tc-score.c (s3_s_score_lcomm): Likewise.
* config/tc-score7.c (s7_s_score_lcomm): Likewise.
* config/tc-sh.c (sh_cons_align): Likewise.
* config/tc-sparc.c (s_reserve, s_common): Likewise.
(sparc_cons_align): Likewise.
* config/tc-tic4x.c (tic4x_seg_alloc, tic4x_bss): Likewise.
* config/tc-tic54x.c (tic54x_bss, tic54x_space): Likewise.
(tic54x_usect, tic54x_field): Likewise.
* config/tc-tic6x.c (s_tic6x_scomm): Likewise.
* config/tc-v850.c (v850_offset, v850_comm): Likewise.
* frags.c (frag_align, frag_align_pattern, frag_align_code): Likewise.
* gen-sframe.c (output_sframe_row_entry): Likewise.
(output_sframe_funcdesc): Likewise.
* read.c (s_fill, do_org, s_space, emit_leb128_expr): Likewise.
* symbols.c (colon)): Likewise.
This patch convenes a set of changes in bfd, gas, ld, libsframe towards
moving to the new encoding for the 'sfde_func_start_address' field in
SFrame FDE.
First, gas must now mark all SFrame sections with the new flag
SFRAME_F_FDE_FUNC_START_PCREL. gas was already emitting the field
in the said encoding.
* gas/gen-sframe.c (output_sframe_internal): Emit the flag
SFRAME_F_FDE_FUNC_START_PCREL.
Similarly for ld, adopt the new semantics of sfde_func_start_address
consistently. This means:
- When merging SFrame sections, check that all input SFrame sections
have the SFRAME_F_FDE_FUNC_START_PCREL flag set. If the check
fails, ld errors out.
- When merging SFrame sections, keep even the in-memory contents of
the FDE function start address (buffer passed to libsframe
sframe_encoder_write () for writing out) encoded in the new
semantics. While it is, in theory, possible that instead of doing this
change here, we adjust the value of sfde_func_start_address at the final
write (sframe_encoder_write) time. But latter is not favorable for
maintenanance and may be generally confusing for developers.
- When creating SFrame for PLT entries, emit flag
SFRAME_F_FDE_FUNC_START_PCREL.
include/
* sframe-api.h (SFRAME_F_LD_MUSTHAVE_FLAGS): New definition.
bfd/
* elf-sframe.c (_bfd_elf_merge_section_sframe): Check for flag
combinatation SFRAME_F_LD_MUSTHAVE_FLAGS set for all input and
output SFrame sections. If not, error out. Also, adopt the new
semantics of function start address encoding.
* bfd/elfxx-x86.c (_bfd_x86_elf_create_sframe_plt): Emit flag
SFRAME_F_FDE_FUNC_START_PCREL.
Next, for dumping SFrame sections, now that we are emitting the same
encoding in GAS, non-relocatable and relocatable SFrame links, it is the
time to set relocate to TRUE in debug_displays[].
binutils/
* dwarf.c (struct dwarf_section_display): Allow sframe sections
to now be relocated.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe-aarch64-pac-ab-key-1.d: Update the
test. Relocatable SFrame sections now display non-zero value
(appropriate function start address).
Now, as the SFrame sections on-disk and in-memory use the new semantics of
sfde_func_start_address encoding (i.e., function start address is the
offset from the sfde_func_start_address field to the start PC), the
calculation to make it human readable (i.e., relatable to the addresses
in .text sections) needs adjustment.
libsframe/
* sframe-dump.c (dump_sframe_func_with_fres): Adjust the
function start address for dumping.
Now that both the emission of the new encoding, and the relocation of
sections before dumping them is in place, it is time to adjust the
testcases.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe-aarch64-1.d: Update expected output
to include SFRAME_F_FDE_FUNC_START_PCREL instead of NONE.
* gas/cfi-sframe/cfi-sframe-aarch64-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-aarch64-3.d: Likewise.
* gas/cfi-sframe/cfi-sframe-aarch64-4.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-10.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-11.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-3.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-4.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-5.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-6.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-7.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-8.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-9.d: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-3.d: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-4.d: Likewise.
* gas/cfi-sframe/common-empty-1.d: Likewise.
* gas/cfi-sframe/common-empty-2.d: Likewise.
* gas/cfi-sframe/common-empty-3.d: Likewise.
* gas/scfi/x86_64/scfi-cfi-sections-1.d: Likewise.
* gas/scfi/x86_64/scfi-dyn-stack-1.d: Likewise.
ld/testsuite/
* ld-aarch64/sframe-simple-1.d: Update expected output to
include SFRAME_F_FDE_FUNC_START_PCREL.
* ld-x86-64/sframe-ibt-plt-1.d: Likewise.
* ld-x86-64/sframe-plt-1.d: Likewise.
* ld-x86-64/sframe-pltgot-1.d: Likewise.
* ld-x86-64/sframe-pltgot-2.d: Likewise.
* ld-x86-64/sframe-simple-1.d: Likewise.
Naturally, the change of semantics for 'SFrame FDE function start address'
has consequences on the implementation in libsframe. As per the new
semantics:
- Function start address in the SFrame FDE (sfde_func_start_address)
is an offset from the FDE function start address field to the start
PC of the associated function.
Note that, the libsframe library brings the SFrame section contents into
its own memory to create a sframe_decoder_ctx object via sframe_decode
(). Many internal and user-interfacing APIs then may use
sframe_decoder_ctx object to interact and fulfill the work.
In context of changing semantics for sfde_func_start_address, following
relevant examples may help understand the impact:
- sframe_find_fre () finds a the SFrame stack trace data (SFrame FRE)
given a lookup offset (offset of lookup_pc from the start of SFrame
section). Now that the sfde_func_start_address includes the
distance from the sfde_func_start_address field to the start of
SFrame section itself, the comparison checks of
sfde_func_start_address with the incoming lookup offset need
adjustment.
- Some internal functions (sframe_get_funcdesc_with_addr_internal ()
finds SFrame FDE by using binary seach comparing
sfde_func_start_address fields, etc.) need adjustments.
- sframe_encoder_write () sorts the SFrame FDEs before writing out
the SFrame data. Sorting of SFrame FDE via the internal function
sframe_sort_funcdesc() needs adjustments: the new encoding of
sfde_func_start_address means the distances are not from the same
anchor, so cannot be sorted directly.
This patch takes the approach of adding a new internal function:
- sframe_decoder_get_secrel_func_start_addr (): This function returns
the offset of the start PC of the function from the start of SFrame
section, i.e., it gives a section-relative offset.
As the sframe_decoder_get_secrel_func_start_addr () API needs the value
of the function index in the FDE list, another internal API needs
sframe_fre_check_range_p () adjustments too.
Sorting the FDEs (via sframe_sort_funcdesc ()) is done by first bringing
all offsets in sfde_func_start_address relative to start of SFrame
section, followed by sorting, and then readjusting the offsets accroding
to the new position in the FDE list.
libsframe/
* sframe.c (sframe_decoder_get_secrel_func_start_addr): New
static function.
(sframe_fre_check_range_p): Adjust the interface a bit.
(sframe_get_funcdesc_with_addr_internal): Use
sframe_decoder_get_secrel_func_start_addr () when comparing
sfde_func_start_address with user input offset.
(sframe_find_fre): Adopt the new semantics.
(sframe_sort_funcdesc): Likewise.
For the libsframe testsuite, use the new encoding for FDE func start
addr: distance between the FDE sfde_func_start_address field and the
start PC of the function itself.
Use SFRAME_F_FDE_FUNC_START_PCREL flag, though the sframe_encode ()
interface in libsframe applies no sanity checks for the encoding itself.
libsframe/testsuite/
* libsframe.find/findfre-1.c: Adjust to use the new
SFRAME_F_FDE_FUNC_START_PCREL specific encoding.
* libsframe.find/findfunc-1.c: Likewise.
* libsframe.find/plt-findfre-1.c: Likewise.
* libsframe/testsuite/libsframe.decode/DATA2: Update data file
due to usage of new SFRAME_F_FDE_FUNC_START_PCREL flag.
* libsframe/testsuite/libsframe.encode/encode-1.c: Use flag
SFRAME_F_FDE_FUNC_START_PCREL.
Fix PR gas/32953 - sframe: incorrect handling of .cfi_same_value in gas
As per documentation, .cfi_same_value indicates that the current value
of register is the same like in the previous frame, i.e. no restoration
needed.
gas/
* gen-sframe.c (sframe_xlate_do_same_value): New definition.
(sframe_do_cfi_insn): Handle DW_CFA_same_value.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe.exp: Add new tests.
* gas/cfi-sframe/cfi-sframe-common-11.d: New test.
* gas/cfi-sframe/cfi-sframe-common-11.s: New test.
Fix PR gas/32952 - sframe: incorrect handling of .cfi_undefined in gas
In context of SFrame generation, it is incorrect to simply ignore all
.cfi_undefined. We may ignore only those .cfi_undefined which are for
registers of no interest (similar to whats done for other CFI
directives).
gas/
* gen-sframe.c (sframe_xlate_do_cfi_undefined): New definition.
(sframe_do_cfi_insn): Handle .cfi_undefined.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe.exp: Add new tests.
* gas/cfi-sframe/cfi-sframe-common-10.d: New test.
* gas/cfi-sframe/cfi-sframe-common-10.s: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-4.d: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-4.s: New test.
The current warning text of "skipping SFrame FDE" does not unabiguously
indicate that the SFrame FDE is not generated in the output section.
Reword the diagnostic to say "no SFrame FDE emitted" as requested.
Adjust the testcases for the updated warning.
To process some CFI directives like .cfi_undefined and .cfi_same_value,
it is necessary for correctness to detect all cases when the register
used is one of SP, FP or RA.
Currently, the backends needed to specify the SFRAME_CFA_RA_REG only in
the case of those ABIs where RA tracking was necessary, e.g. AArch64.
For AMD64, since the return address is always at a fixed offset from the
CFA, RA tracking was disabled.
The backends must now specify the applicable return address register via
SFRAME_CFA_RA_REG. This is necessary so that SFrame generation code can
then properly handle the cases when RA is used like so:
.cfi_undefined <RA>
or,
.cfi_same_value <RA>
Detecting these cases is necessary for correctness. E.g., on AMD64, we
need to skip FDE generation as the above constructs cannot be
represented in SFrame yet.
This change is a prerequisite to fixing the two PRs:
PR gas/32952 - sframe: incorrect handling of .cfi_undefined in gas
PR gas/32953 - sframe: incorrect handling of .cfi_same_value in gas
In the SFrame generation code in gen-sframe.c, instead of using
SFRAME_FRE_RA_TRACKING ifdef's, we now simply rely on the API
sframe_ra_tracking_p () to detect if RA-tracking is enabled for the
target.
While at it, use const variables for x86 backend.
ChangeLog:
* gas/config/tc-i386.c (x86_sframe_cfa_ra_reg): New definition.
* gas/config/tc-i386.h (REG_RA): New definition.
(SFRAME_CFA_RA_REG): New declaration.
* gas/gen-sframe.c (SFRAME_FRE_RA_TRACKING): Remove.
Each SFrame FDE contains an offset to the start of its respective SFrame
FREs in the sfde_func_start_fre_off field. To generate this offset,
fre_symbols[] array is being used. The number of elements of this array
is currently set to the total number of SFrame FREs in the entire SFrame
section. This is more than unnecessary. We only need to track as many
points as the number of SFrame FDEs.
gas/
* gen-sframe.c (output_sframe_internal): Size fde_fre_symbols
with the number of SFrame FDEs.
Fix PR gas/32879 sframe: Assembler internal error when translating
cfi_def_cfa_register
As per the documentation, .cfi_def_cfa_register modifies a rule for
computing CFA; the register is updated, but the offset remains the same.
While translating .cfi_def_cfa_register into SFrame context, we use the
information from last translated FRE to set the CFA offset. However,
there may be cases when the last translated FRE is empty. Use last FRE
only if available.
Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>
Signed-off-by: Indu Bhagat <indu.bhagat@oracle.com>
Ignoring return values often isn't a good idea. The Sparc assembler in
particular would report an internal error if an expression with
relocation specifier is used with .cfi_escape, when the same works fine
with .byte. Propagate the relocation indicator up from
do_parse_cons_expression(), and eventually into emit_expr_with_reloc().
dot_cfi_fde_data(), only retaining the expression's X_add_number, would
require further work. Simply report the lack of support there. While
there, also check that what we were dealt is actually a constant.
The use of SFRAME_RELOC_SIZE in generation of SFrame stack trace
information from CFI directives erroneously suggested that this could
be used to configure a different relocation size. But in practice it
is tied to the SFrame field sizes it is used for and therefore cannot
be changed.
Replace the uses of SFRAME_RELOC_SIZE by the size of the respective
SFrame header and FDE fields when emitting SFrame information. While
at it enhance some comments.
gas/
* gen-sframe.c (SFRAME_RELOC_SIZE): Delete.
(sizeof_member): Define.
(output_sframe_funcdesc): Use size of SFrame FDE fields instead
of SFRAME_RELOC_SIZE.
(output_sframe_internal): Use size of SFrame header fields
instead of SFRAME_RELOC_SIZE.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
CFI_escape is most commonly used to include DWARF expressions in the
unwind information. One may also use CFI_escape to add OS-specific CFI
opcodes. Up until now, SFrame generation process would skip generating
SFrame FDE at the mere sight of a CFI_escape opcode.
Fine tune the handling of CFI_escape for SFrame generation by explicitly
checking for few "harmless" (in context of SFrame generation)
CFI_escape DWARF info:
- DW_CFA_expression affecting registers of no significance to SFrame
stack trace info
- DW_CFA_value_offset affecting registers of no significance to SFrame
stack trace info
Expose the current cfi_escape_data structure in dw2gencfi.c to the
relevant header file to allow SFrame generation APIs to use it too.
Valid unwind info may be split across multiple .cfi_escape directives.
Conversely, it is also allowed to simply put multiple DWARF expressions
and/or operations in a single .cfi_escape directive. Handling all of
these cases correctly will need parsing/processing that is not deemed
worth the effort in context of SFrame generation; We continue to skip
generating SFrame FDE for these cases and warn the user.
In future, SFrame stack trace format may support non-SP/FP as base
register (albeit in limited form). Add an explicit check in
sframe_xlate_do_escape_expr (to test against the current CFA register)
to ensure the functionality continues to work.
Use differentiated warning text in sframe_xlate_do_val_offset to avoid
confusion to the user as the same function is used for handling
.cfi_val_offset and .cfi_escape DW_CFA_val_offset,...
Also, add a common test with DWARF reg 12 which is non SP / FP on x86_64
and aarch64 (and s390x too).
gas/
* gas/dw2gencfi.c (struct cfi_escape_data): Move from ...
* gas/dw2gencfi.h (struct cfi_escape_data): ... to.
* gas/gen-sframe.c (sframe_xlate_do_val_offset): Include string
for .cfi_escape conditionally.
(sframe_xlate_do_escape_expr): New definition.
(sframe_xlate_do_escape_val_offset): Likewise.
(sframe_xlate_do_cfi_escape): Likewise.
(sframe_do_cfi_insn): Handle CFI_escape explicitly.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe.exp: Add new tests.
* gas/cfi-sframe/cfi-sframe-common-9.d: New test.
* gas/cfi-sframe/cfi-sframe-common-9.s: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-1.d: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-1.s: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-2.d: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-2.s: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-3.d: New test.
* gas/cfi-sframe/cfi-sframe-x86_64-empty-3.s: New test.
Unwinding of the stack pointer (SP) is performed using the assumed
default rule ".cfi_val_offset <SP-reg>, 0", so that SP unwinds as:
SP = CFA
Warn if the CFI directive .cfi_val_offset is encountered for the
SP register with a different offset.
gas/
* gen-sframe.c (sframe_xlate_do_val_offset): Skip SFrame FDE
if non-default SP value offset.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Use the appropriate struct cfi_insn_data union members to access
fields when generating SFrame information from CFI directives.
gas/
* gen-sframe.c (sframe_xlate_do_def_cfa, sframe_xlate_do_offset,
sframe_xlate_do_val_offset): Access ri fields, as .cfi_def_cfa,
.cfi_offset, and .cfi_val_offset define a register and offset
value.
* (sframe_xlate_do_def_cfa_register): Access r field, as
.cfi_def_cfa_register defines a register.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Today, SFrame v2 specification does not describe how to encode the
information corresponding to the PAuth_LR PAC signing method (it only
supports PAuth PAC signing method).
SFrame v3 specification should hopefully specify it.
In the meantime, if the GNU assembler finds .cfi_negate_ra_state_with_pc
and --gsframe is specified, it will output a warning to the user and
will fail to generate the FDE entry.
A new SFrame test for .cfi_negate_ra_state_with_pc is also added to
reflect this issue.
Approved-by: Indu Bhagat <indu.bhagat@oracle.com>
- add a detailed comment when parsing DW_CFA_GNU_window_save in SFrame to
explain why we are checking whether the targeted architecture is AArch64,
whereas this CFI is a Sparc extension.
- replace .cfi_gnu_window_save by .cfi_negate_ra_state in existing AArch64
DWARF tests as this is the preferred directive since GCC 15.
- add a new AArch64 test to check backward compatibility with old GCC
versions that emits .cfi_gnu_window_save.
Approved-by: Indu Bhagat <indu.bhagat@oracle.com>
Approved-by: Richard Earnshaw <richard.earnshaw@arm.com>
Verify all architectures participating in SFrame generation do define
the mandatory SFrame return address (RA) tracking predicate function
sframe_ra_tracking_p. Do so by explicitly not testing for the macro
SFRAME_FRE_RA_TRACKING as otherwise required.
Verify that architectures not using SFrame RA tracking specify a valid
fixed RA offset.
gas/
* gen-sframe.c (output_sframe_internal): Validate SFrame
RA tracking and fixed RA offset.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
The existence of the macro SFRAME_FRE_RA_TRACKING only ensures the
existence of the macro SFRAME_CFA_RA_REG and the predicate function
sframe_ra_tracking_p. It does not indicate whether SFrame RA tracking
is actually used.
Test the return value of the SFrame RA tracking predicate function
sframe_ra_tracking_p to determine whether RA tracking is used.
This aligns the logic in functions get_fre_num_offsets and
output_sframe_row_entry to the one used in all other places.
gas/
* gen-sframe.c (get_fre_num_offsets, output_sframe_row_entry):
Test predicate to determine whether SFrame RA tracking is used.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Neither ".cfi_offset SP, <offset>", ".cfi_register SP, <regno>", nor
".cfi_val_offset SP, <offset>" alter the tracking information to recover
the stack pointer (SP). Doing so would need an explicit .cfi_def_cfa,
which SFrame tracks.
The stack pointer (SP) register contents on entry can be reconstructed
from the SFrame CFA tracking information using information from the
current and initial SFrame FREs of the SFrame FDE:
1. Compute CFA from the current CFA base register (SP or FP) and CFA
offset from the SFrame CFA tracking information from the SFrame FRE
for the current instruction address:
CFA = <current_base_reg> + <current_cfa_offset>
2. Compute SP from the current CFA and the CFA offset from the SFrame
CFA tracking information from the initial SFrame FRE of the FDE:
SP = CFA - <initial_cfa_offset>
While at it add comments to the processing of .cfi_offset and
.cfi_val_offset that the SP can be reconstructed from the CFA tracking
information.
gas/
* gen-sframe.c (sframe_xlate_do_register): Do not skip SFrame
FDE if .cfi_register specifies SP register.
(sframe_xlate_do_offset,sframe_xlate_do_val_offset): Add comment
that this is likewise.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Do not skip SFrame FDE if .cfi_register specifies RA register without
RA tracking being actually used. Without RA tracking the register
contents can always be restored from the stack using the fixed
RA offset from CFA.
gas/
* gen-sframe.c (sframe_xlate_do_register): Do not skip SFrame
FDE if .cfi_register specifies RA register without RA tracking
being used.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
CFI opcode DW_CFA_AARCH64_negate_ra_state is multiplexed with
DW_CFA_GNU_window_save. Process DW_CFA_AARCH64_negate_ra_state on
AArch64. Skip generation of SFrame FDE otherwise with the following
warning message:
skipping SFrame FDE; .cfi_window_save
gas/
* gen-sframe.c: Skip SFrame FDE if .cfi_window_save.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
The SFrame format cannot represent the frame pointer (FP) being saved
on the stack without the return address (RA) also being saved on the
stack, if RA tracking is used.
A SFrame FDE is followed by 1-3 offsets with the following information:
Without RA tracking:
1. Offset from base pointer (SP or FP) to locate the CFA
2. Optional: Offset to CFA to restore the frame pointer (FP)
With RA tracking:
1. Offset from base pointer (SP or FP) to locate the CFA
2. Optional: Offset to CFA to restore the return address (RA)
3. Optional: Offset to CFA to restore the frame pointer (FP)
When RA tracking is used and a FDE is followed by two offsets the
SFrame format does not provide any information to distinguish whether
the second offset is the RA or FP offset. SFrame assumes the offset to
be the RA offset, which may be wrong.
Therefore skip generation of SFrame FDE information and print the
following warning, if RA tracking is used and the FP is saved on the
stack without the RA being saved as well:
skipping SFrame FDE; FP without RA on stack
gas/
* gen-sframe.c (sframe_do_fde): Skip SFrame FDE if FP without RA
on stack, as the SFrame format cannot represent this case.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
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>
Refactor SFrame processing of CFI opcode DW_CFA_register into a separate
function. This harmonizes the CFI opcode processing.
While at it reword the comment on CFI opcodes that are not processed.
This is a purely mechanical change.
gas/
* gen-sframe.c (sframe_do_cfi_insn, sframe_xlate_do_register):
Refactor SFrame CFI opcode DW_CFA_register processing.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Print a warning message if SFrame FDE is skipped due to a non-default
DWARF return column (i.e. return address (RA) register number). This
may be caused by the use of CFI directive .cfi_return_column with a
non-default return address (RA) register number in the processed
assembler source code.
Warning: skipping SFrame FDE due to non-default DWARF return column
gas/
* gen-sframe.c: Warn if SFrame FDE is skipped due to non-default
DWARF return column.
gas/testsuite/
* gas/cfi-sframe/common-empty-3.d: Update test case to expect
for new warning message when SFrame FDE is skipped due to
a non-default DWARF return column.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Do not generate SFrame FDE if DWARF CFI directives .cfi_def_cfa or
.cfi_def_cfa_register specify a CFA base register number other than
the architecture-specific stack-pointer (SP) or frame-pointer (FP)
register numbers.
This also causes the assembler to print a warning message, so that
skipping of the SFrame FDE does not occur silently.
Update the generic ld SFrame test case to be architecture independent.
Do not use CFI directive .cfi_def_cfa, as the specified CFA base
register number is not a valid SP/FP register number on all
architectures. An invalid SP/FP register number will now cause the
assembler to print a warning message and skip SFrame FDE generation.
Remove the offending CFI directive, that cannot be coded architecture-
independent, as the test case requires SFrame information to be
generated. This was reported by the Linaro-TCWG-CI for AArch64.
gas/
* gen-sframe.c: Skip SFrame generation if CFI specifies
non-FP/SP base register.
ld/testsuite/
* ld-sframe/discard.s: Update generic SFrame test case to be
architecture independent.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
SFrame generation prints the DWARF call frame instruction opcode in
hexadecimal. Leverage get_DW_CFA_name to additionally print the
DWARF call frame instruction name in human readable form, while also
respecting fake CFI types. Use "(unknown)", if the DWARF call frame
instruction name is not known.
While at it use the terminology "instruction" for these DW_CFA_*, as
suggested by Indu.
This changes the following assembler SFrame generation warning message
as follows:
Old:
Warning: skipping SFrame FDE due to DWARF CFI op 0x<hexval>
New:
Warning: skipping SFrame FDE; CFI insn <name> (0x<hexval>)
gas/
* gen-sframe.c (sframe_get_cfi_name): New function to get the
DWARF call frame instruction name for a DWARF call frame
instruction opcode.
(sframe_do_cfi_insn): Use sframe_get_cfi_name to print the
DWARF call frame instruction name for the DWARF call frame
instruction opcode in the warning message.
gas/testsuite/
* gas/cfi-sframe/common-empty-1.d: Update expected SFrame
warning message text for DWARF call frame insn name.
* gas/cfi-sframe/common-empty-2.d: Likewise.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Fix PR gas/31213.
gas/
PR gas/31213
* gen-sframe.c (sframe_do_cfi_insn): Add new warning.
gas/testsuite/
* gas/cfi-sframe/common-empty-1.d: Test the new warning as well.
* gas/cfi-sframe/common-empty-2.d: Likewise.
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.
SFrame version 2 encodes the size of repetitive insn block explicitly
in the format. Add information in the SFrame FDE to convey the size
of the block of repeating instructions. This information is used only
for SFrame FDEs of type SFRAME_FDE_TYPE_PCMASK.
Introduce two extra bytes for padding: this ensures that the memory
accesses to the members of the SFrame Frame Descriptor Entry (FDE) are
naturally aligned.
gas generates SFrame section with version SFRAME_VERSION_2 by default.
libsframe provides two new APIs to:
- get an SFrame FDE data from the decoder context, and
- add an SFrame FDE to the encoder context.
The additional argument (for rep_block_size) is useful for SFrame FDEs
where FDE type is SFRAME_FDE_TYPE_PCMASK.
The linker will generate the output SFrame sections in the
SFRAME_VERSION_2 format. If the input sections offered to the linker
are not all in the SFRAME_VERSION_2 format, the linker issues an error
to the user.
objdump/readelf will show the following message to the user if .sframe
section in SFRAME_VERSION_1 format is seen:
"No further information can be displayed. SFrame version not
supported."
In other words, like the rest of the binutils, only the current SFrame
format version, i.e., SFRAME_VERSION_2 is supported by the textual dump
facilities.
bfd/
* elf-sframe.c (_bfd_elf_merge_section_sframe): Generate an
output SFrame section with version SFRAME_VERSION_2. Also,
error out if the SFrame sections do not all have
SFRAME_VERSION_2.
* elfxx-x86.c (_bfd_x86_elf_create_sframe_plt): Generate SFrame
section for plt entries with version SFRAME_VERSION_2.
gas/
* gen-sframe.c (sframe_set_version): Update to SFRAME_VERSION_2.
(output_sframe): Likewise.
gas/testsuite/
* gas/cfi-sframe/cfi-sframe-aarch64-1.d: Use SFRAME_VERSION_2.
* gas/cfi-sframe/cfi-sframe-aarch64-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-aarch64-pac-ab-key-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-1.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-2.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-3.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-4.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-5.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-6.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-7.d: Likewise.
* gas/cfi-sframe/cfi-sframe-common-8.d: Likewise.
* gas/cfi-sframe/cfi-sframe-x86_64-1.d: Likewise.
* gas/cfi-sframe/common-empty-1.d: Likewise.
* gas/cfi-sframe/common-empty-2.d: Likewise.
* gas/cfi-sframe/common-empty-3.d: Likewise.
ld/testsuite/
* ld-aarch64/sframe-simple-1.d: Adjust for SFRAME_VERSION_2.
* ld-x86-64/sframe-plt-1.d: Likewise.
* ld-x86-64/sframe-simple-1.d: Likewise.
libsframe/
* libsframe.ver: Add the new APIs.
* sframe.c (sframe_decoder_get_funcdesc_v2): New definition.
(sframe_encoder_add_funcdesc_v2): Likewise.
(sframe_header_sanity_check_p): Include SFRAME_VERSION_2.
(sframe_fre_check_range_p): Get rep_block_size info from SFrame
FDE.
* sframe-dump.c (dump_sframe_header): Add support for
SFRAME_VERSION_2.
(dump_sframe): Inform user if SFrame section in SFRAME_VERSION_1
format is seen.
libsframe/testsuite/
* libsframe.decode/DATA-BE: Regenerated data file.
* libsframe.decode/DATA1: Likewise.
* libsframe.decode/DATA2: Likewise.
* libsframe.find/plt-findfre-1.c: Use new API in the testcase.
include/
* sframe.h: Add member to encode size of the code block of
repeating instructions. Add 2 bytes of padding.
* sframe-api.h (sframe_decoder_get_funcdesc_v2): New
declaration.
(sframe_encoder_add_funcdesc_v2): Likewise.
gas/
* gen-sframe.c (sframe_set_version): Use ATTRIBUTE_UNUSED
consistently.
(output_sframe): Likewise.
(sframe_set_fre_info): Remove the usage of ATTRIBUTE_UNUSED.
