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>
Generating the linker dump test list using file globbing makes it
difficult to exclude specific tests under certain circumstances. List
them explicitly instead. This enables to add tests in the future that
can be excluded. While at it reorganize how s390 linker tests get
run for s390x.
ld/testsuite/
* ld-s390/s390.exp: Reorganize and explicitly list linker dump
tests.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
The .sframe section may have a trailing padding due to the architecture-
specific default section alignment. Do not treat this padding as error
when converting between target and host endianness.
This can be observed when building Binutils with SFrame s390x support on
x86-64 for s390x using configure option "--target=s390x-ibm-linux-gnu"
and running the GAS test suite.
While at it reuse the determined SFrame section header size.
libsframe/
* sframe.c (flip_sframe): Ignore .sframe section padding. Reuse
SFrame header size.
Reported-by: Indu Bhagat <indu.bhagat@oracle.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Swap AM_PO_SUBDIRS and ZW_GNU_GETTEXT_SISTER_DIR lines in
*/configure.ac. ZW_GNU_GETTEXT_SISTER_DIR indirectly invokes
AC_REQUIRE(AM_PO_SUBDIRS) so results in AM_PO_SUBDIRS being emitted
before ZW_GNU_GETTEXT_SISTER_DIR if it hasn't already been invoked.
The v850 md_convert_frag function oddly calls subseg_change twice
(commit 1cd986c585). Neither call is needed, because that is done
in size_seg.
Convert the fr_opcode fixup field back (to an opindex, not fx_r_type)
using a cast rather than a union, since we used casts when setting up
those values. I guess the union was added to silence compiler
warnings about wrong-size casts, but unfortunately results in the
wrong value being retrieved on big-endian hosts.
Change "buffer" to a char* as there is no need to make it an
unsigned char*, and that way requires fewer casts. Finally, fix
formatting and use uintptr_t when make the rs_machine_dependent frags.
Remove subseg_change calls from cr16, crx, mn10200, mn10300, and sh
md_convert_frag too.
Rename the old enum alpha_macro_arg to alpha_macro_argset, and create
a union alpha_macro_arg to use in all the alpha_macro.emit functions.
This avoids intptr_t casts on retrieving index values and void* casts
on storing them in the alpha_macros array.
The entry of "zce imply zcf" needs check_implicit_for_zcf, so it needs to be
placed after the entries of "whatever imply f". Otherwise the implicit zcf
may be missed. Also merge the march-implu-zce* testcases into imply testcases.
This also fix the imply result for .option rvc.
Imply zcf when c and f and rv32
Imply zcd when c and d
Imply zca when c
Changed INSN_CLASS_C to INSN_CLASS_ZCA
Changed INSN_CLASS_F_AND_C to INSN_CLASS_ZCF
Changed INSN_CLASS_D_AND_C to INSN_CLASS_ZCD
Changed INSN_CLASS_ZIHINTNTL_AND_C to INSN_CLASS_ZIHINTNTL_AND_ZCA
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.
init_private_section_data is used by the linker and is a special case
of copy_private_section_data that copies a reduced set of section data
from input to output. Merge the two functions, adding a link_info
param to copy_private_section_data and remove init_private_section_data.
The point here is that when valueT is 64 bits and int is 32 bits,
1 << align doesn't work for shifts larger than the size of int. (Not
that anyone is likely to use such large alignments in real code.)
This patch removes many unneeded casts to char or unsigned char. It's
worth noting that safe-ctype.h macros ISDIGIT and the like cope with
either signed or unsigned char.
In some cases a cast to unsigned char is replaced by anding with 0xff,
which accomplishes the same thing but doesn't rely on char being eight
bits. The patch also removes pointer casts, and a few unsigned char
pointer variables.
Use standard sign extend and range checking using unsigned
expressions that don't rely on implementation defined right shifts or
size of short and int.
Calls to md_number_to_chars don't need to cast their value arg (*).
Remove those casts. avr_output_property_recode made a call to
md_number_to_chars with size of 1. Simplify that. tc-bpf.c
md_convert_frag used write_insn_bytes that simply copied input to
output. Dispense with that nonsense, and similarly in a couple of
other places where md_number_to_chars was called with size 1.
*) unless the value arg is an expression that needs a cast, eg. tic54x
emit_insn where the shift left could trigger signed overflow UB
without a cast.
This removes assorted unneeded casts of void* pointers, and casts when
passing args to void* parameters or storing to void* pointers. The
patch also changes obj-coff.c stack_push to take a void* parameter,
and replaces an odd memcpy in tc-metag.c find_insn_templates with a
simple assignment.
This removes a bunch of casts involving const pointers, in some cases
by making variables const pointers so a cast is not needed. In a
couple of places the cast hid errors with "&array" written rather than
"array", see iq2000_macro_defs and s_pru_align. tc-xgate.c cmp_opcode
is changed to be the standard qsort predicate to avoid a function
cast.
bfd_{h_,}put_* and bfd_{h_,}get_* have "void *" pointer params
nowadays. We don't need casts on their pointer args. We also don't
need to cast values passed to bfd_put.
This removes many unnecessary NULL casts. I'm also adding a few arg
casts in concat calls, to make the code consistent. Advice from quite
a few years ago was that it's better to use the exact type for args
corresponding to function ellipses, in case NULL is defined as plain
0. (I think that happened with some early 64-bit systems. Plain NULL
ought to be OK nowadays.)
Enumeration constants are integer types, so there should be no need to
cast such constants to int in expressions. (Perhaps some older gccs
warned, I checked back to gcc-4.5.) Remove some of those unnecessary
casts. Also remove unnecessary casts to bfd_reloc_code_real_type.
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.
Use "intptr_t" or "uintptr_t" for these conversions, not "long" which
is wrong on LLP64 systems, or "size_t" which is better but still not
the correct type.
* config/tc-alpha.c (emit_ldXu, emit_ldX, emit_uldXu, emit_uldX),
(emit_stX, emit_ustX, emit_sextX): Use correct type when
converting vlgsize pointer to in. Use "int" rather than
"long" for result.
* config/tc-ia64.c (generate_unwind_image): Use intptr_t cast
when passing personality_routine to frag_var.
* config/tc-ppc.c (ppc_frob_symbol <coff>): Use uintptr_t cast
when converting symbol pointer to valueT.
* config/tc-v850.c (md_assemble): Use intptr_t cast when
loading integer opindex.
add support to recording 2 missing AVX instructions: vaddsubps and vaddsubpd, and add associated tests.
Approved-By: Guinevere Larsen <guinevere@redhat.com>
Use bfd_follow_gnu_debuglink() and bfd_follow_gnu_debugaltlink() to find files
with debug info.
If necessary, gprofng-archive copies these files to EXP/archives.
For each executable, gprofng creates the Elf class twice.
One of them was a memory leak.
Fixed this by adding a new argument to Stabs::Stabs().
gprofng/ChangeLog
2025-07-07 Vladimir Mezentsev <vladimir.mezentsev@oracle.com>
PR 32147
PR 30194
* src/Disasm.cc (get_funcname_in_plt): Use the executable file instead
of the debug information file.
* src/Dwarf.h: Define debug_alt_strSec.
* src/DwarfLib.cc: Add support for DW_FORM_GNU_ref_alt,
DW_FORM_GNU_strp_alt.
* src/Elf.h (find_gnu_debug_files, get_dwr_section): New functions.
* src/Elf.cc: Likewise.
* src/Experiment.cc (copy_file): Add the const qualifier.
* src/Experiment.h: Likewise.
* src/LoadObject.cc (get_elf, openDebugInfo): Find files with debug info.
* src/LoadObject.h: Remove unused variables.
* src/Module.cc: Remove an argument in openDebugInfo().
* src/Stabs.cc (Stabs::Stabs): Add the Elf* argument.
* src/Stabs.h: Likewise.
* src/gp-archive.cc: Archive files with debug info.
* src/gp-archive.h (archive_file): New function.
A recent patch of mine modified wchar.exp, but I failed to notice one
part of the review. This patch updates the code to conform to the
review comments.
When building a cross-compiler ld for RISC-V Linux systems, you can specify
target=riscv64*-linux* to create a linker that supports both 32-bit
(-march=rv32*) and 64-bit (-march=rv64*) architectures. The specified -march
value populates the EMULATION_NAME variable, which determines the default
linker script selection. For proper riscv64 target support, the build process
must prepare both elf32lriscv* and elf64lriscv* linker scripts. These should
align with the standard RISC-V Linux sysroot directory structure.
Signed-off-by: Mark Goncharov <mark.goncharov@syntacore.com>
