The eBPF loader expects to find entries for functions declared as extern
in the corresponding BTF_KIND_DATASEC record, but we were not generating
these entries.
This patch adds support for the 'extern' linkage of function types in
BTF, and creates entries for for them BTF_KIND_DATASEC records as needed.
PR target/106773
gcc/
* btfout.cc (get_section_name): New function.
(btf_collect_datasec): Use it here. Process functions, marking them
'extern' and generating DATASEC entries for them as appropriate. Move
creation of BTF_KIND_FUNC records to here...
(btf_dtd_emit_preprocess_cb): ... from here.
gcc/testsuite/
* gcc.dg/debug/btf/btf-datasec-2.c: New test.
* gcc.dg/debug/btf/btf-function-6.c: New test.
include/
* btf.h (enum btf_func_linkage): New.
(struct btf_var_secinfo): Update comments with notes about extern
functions.
Add support for the 'extern' linkage value for BTF_KIND_VAR records,
which is used for variables declared as extern in the source file.
This also fixes a bug with BTF generation for extern variables which
have both a non-defining declaration and a defining declaration in the
same CU.
PR target/106773
gcc/
* btfout.cc (btf_collect_datasec): Mark extern variables as such.
(btf_dvd_emit_preprocess_cb): Skip non-defining extern variable decl
if there is a defining decl for the same variable.
(btf_asm_varent): Accomodate 'extern' linkage.
gcc/testsuite/
* gcc.dg/debug/btf/btf-variables-4.c: New test.
* gcc.dg/debug/btf/btf-variables-5.c: New test.
include/
* btf.h (enum btf_var_linkage): New.
(struct btf_var): Update comment to note 'extern' linkage.
BTF supports 64-bits enumerators with following encoding:
struct btf_type:
name_off: 0 or offset to a valid C identifier
info.kind_flag: 0 for unsigned, 1 for signed
info.kind: BTF_KIND_ENUM64
info.vlen: number of enum values
size: 1/2/4/8
The btf_type is followed by info.vlen number of:
struct btf_enum64
{
uint32_t name_off; /* Offset in string section of enumerator name. */
uint32_t val_lo32; /* lower 32-bit value for a 64-bit value Enumerator */
uint32_t val_hi32; /* high 32-bit value for a 64-bit value Enumerator */
};
So, a new btf_enum64 structure was added to represent BTF_KIND_ENUM64
and a new field dtd_enum_unsigned in ctf_dtdef structure to distinguish
when CTF enum is a signed or unsigned type, later that information is
used to encode the BTF enum type.
gcc/ChangeLog:
* btfout.cc (btf_calc_num_vbytes): Compute enumeration size depending of
enumerator type btf_enum{,64}.
(btf_asm_type): Update btf_kflag according to enumeration type sign
using dtd_enum_unsigned field for both: BTF_KIND_ENUM{,64}.
(btf_asm_enum_const): New argument to represent the size of
the BTF enum type, writing the enumerator constant value for
32 bits, if it's 64 bits then explicitly writes lower 32-bits
value and higher 32-bits value.
(output_asm_btf_enum_list): Add enumeration size argument.
* ctfc.cc (ctf_add_enum): New argument to represent CTF enum
basic information.
(ctf_add_generic): Use of ei_{name. size, unsigned} to build the
dtd structure containing enumeration information.
(ctf_add_enumerator): Update comment mention support for BTF
enumeration in 64-bits.
* dwarf2ctf.cc (gen_ctf_enumeration_type): Extract signedness
for enumeration type and use it in ctf_add_enum.
* ctfc.h (ctf_dmdef): Update dmd_value to HOST_WIDE_INT to allow
use 32/64 bits enumerators.
information.
(ctf_dtdef): New field to describe enum signedness.
include/
* btf.h (btf_enum64): Add new definition and new symbolic
constant to BTF_KIND_ENUM64 and BTF_KF_ENUM_{UN,}SIGNED.
gcc/testsuite/ChangeLog:
* gcc.dg/debug/btf/btf-enum-1.c: Update testcase, with correct
info.kflags encoding.
* gcc.dg/debug/btf/btf-enum64-1.c: New testcase.
Add BTF_KIND_FLOAT, a new BTF type kind which has recently stabilized in
the linux kernel [1]. This kind is used for encoding floating point
types, and is of particular use when generating BTF for some s390
arch-specific kernel headers.
Also update some BTF tests which previously used floating point types to
check correct behavior for types with no BTF representation.
[1]: b1828f0b04
include/ChangeLog:
* btf.h (struct btf_type): Update bit usage comment.
(BTF_INFO_KIND): Update bit mask.
(BTF_KIND_FLOAT): New define.
(BTF_KIND_MAX): Update.
gcc/ChangeLog:
* btfout.c (get_btf_kind): Support BTF_KIND_FLOAT.
(btf_asm_type): Likewise.
gcc/testsuite/ChangeLog:
* gcc.dg/debug/btf/btf-float-1.c: New test.
* gcc.dg/debug/btf/btf-function-3.c: Use different unrepresentable type.
* gcc.dg/debug/btf/btf-struct-2.c: Likewise.
* gcc.dg/debug/btf/btf-variables-2.c: Likewise.
This commit introduces support for generating CTF debugging
information and BTF debugging information from GCC.
2021-06-28 Indu Bhagat <indu.bhagat@oracle.com>
David Faust <david.faust@oracle.com>
Jose E. Marchesi <jose.marchesi@oracle.com>
Weimin Pan <weimin.pan@oracle.com>
gcc/
* Makefile.in: Add ctfc.*, ctfout.c and btfout.c files to
GTFILES. Add new object files.
* common.opt: Add CTF and BTF debug info options.
* btfout.c: New file.
* ctfc.c: Likewise.
* ctfc.h: Likewise.
* ctfout.c: Likewise.
* dwarf2ctf.c: Likewise.
* dwarf2ctf.h: Likewise.
* dwarf2cfi.c (dwarf2out_do_frame): Acknowledge CTF_DEBUG and
BTF_DEBUG.
* dwarf2out.c (dwarf2out_source_line): Likewise.
(dwarf2out_finish): Skip emitting DWARF if CTF or BTF are to
be generated.
(debug_format_do_cu): New function.
(dwarf2out_early_finish): Traverse DIEs and emit CTF/BTF for
them if requested.
Include dwarf2ctf.c.
* final.c (dwarf2_debug_info_emitted_p): Acknowledge DWARF-based debug
formats.
* flag-types.h (enum debug_info_type): Add CTF_DEBUG and BTF_DEBUG.
(CTF_DEBUG): New bitmask.
(BTF_DEBUG): Likewise.
(enum ctf_debug_info_levels): New enum.
* gengtype.c (open_base_files): Handle ctfc.h.
(main): Handle uint32_t type.
* flags.h (btf_debuginfo_p): New definition.
(dwarf_based_debuginfo_p): Likewise.
* opts.c (debug_type_names): Add entries for CTF and BTF.
(btf_debuginfo_p): New function.
(dwarf_based_debuginfo_p): Likewise.
(common_handle_option): Handle -gctfN and -gbtf options.
(set_debug_level): Set CTF_DEBUG, BTF_DEBUG whenever appropriate.
* toplev.c (process_options): Inform the user and ignore -gctfLEVEL if
frontend is not C.
include/
* ctf.h: New file.
* btf.h: Likewise.
libiberty/
* simple-object.c (handle_lto_debug_sections): Copy over .ctf
sections.
