Hi Guillermo,
Thanks for the patch. Just a couple of small nits on the changelog
entries below but otherwise very nice, LGTM.
But, please wait a couple of days before pushing to give Indu time
to raise any objections about the changes in ctfc/dwarf2ctf.
Thanks!
David
On 8/29/22 14:11, Guillermo E. Martinez via Gcc-patches wrote:
> Hello GCC team,
>
> The following patch update BTF/CTF backend to support
> BTF_KIND_ENUM64 type.
>
> Comments will be welcomed and appreciated!,
>
> Kind regards,
> guillermo
> --
>
> 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 in ctf_dtdef to represent specific type's properties, in
> the particular case for CTF enums it helps to distinguish when its
> enumerators values are signed or unsigned, 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 enumerators sign,
> using correct BPF type in BTF_KIND_ENUMi{,64}.
> (btf_asm_enum_const): New argument to represent the size of
> the BTF enum type.
> * ctfc.cc (ctf_add_enum): Use and initialization of flag field to
> CTF_ENUM_F_NONE.
> (ctf_add_enumerator): New argument to represent CTF flags,
> updating the comment and flag vaue according to enumerators
> sing.
> * ctfc.h (ctf_dmdef): Update dmd_value to HOST_WIDE_INT to allow
> use 32/64 bits enumerators.
> (ctf_dtdef): Add flags to to describe specifyc type's properties.
typo: specific
> * dwarf2ctf.cc (gen_ctf_enumeration_type): Update flags field
> depending when a signed enumerator value is found.
> include/btf.h (btf_enum64): Add new definition and new symbolic
> constant to BTF_KIND_ENUM64 and BTF_KF_ENUM_{UN,}SIGNED.
Missing an * here for include/btf.h
>
> 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.
Likewise for these ChangeLog entries.
You can use contrib/gcc-changelog/git_check_commit.py to check the
formatting of the entries.
> ---
> gcc/btfout.cc | 24 ++++++++---
> gcc/ctfc.cc | 14 ++++---
> gcc/ctfc.h | 9 +++-
> gcc/dwarf2ctf.cc | 9 +++-
> gcc/testsuite/gcc.dg/debug/btf/btf-enum-1.c | 2 +-
> gcc/testsuite/gcc.dg/debug/btf/btf-enum64-1.c | 41 +++++++++++++++++++
> include/btf.h | 19 +++++++--
> 7 files changed, 99 insertions(+), 19 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/debug/btf/btf-enum64-1.c
>
> diff --git a/gcc/btfout.cc b/gcc/btfout.cc
> index 997a33fa089..4b11c867c23 100644
> --- a/gcc/btfout.cc
> +++ b/gcc/btfout.cc
> @@ -223,7 +223,9 @@ btf_calc_num_vbytes (ctf_dtdef_ref dtd)
> break;
>
> case BTF_KIND_ENUM:
> - vlen_bytes += vlen * sizeof (struct btf_enum);
> + vlen_bytes += (dtd->dtd_data.ctti_size == 0x8)
> + ? vlen * sizeof (struct btf_enum64)
> + : vlen * sizeof (struct btf_enum);
> break;
>
> case BTF_KIND_FUNC_PROTO:
> @@ -622,6 +624,15 @@ btf_asm_type (ctf_container_ref ctfc, ctf_dtdef_ref dtd)
> btf_size_type = 0;
> }
>
> + if (btf_kind == BTF_KIND_ENUM)
> + {
> + btf_kflag = (dtd->flags & CTF_ENUM_F_ENUMERATORS_SIGNED)
> + ? BTF_KF_ENUM_SIGNED
> + : BTF_KF_ENUM_UNSIGNED;
> + if (dtd->dtd_data.ctti_size == 0x8)
> + btf_kind = BTF_KIND_ENUM64;
> + }
> +
> dw2_asm_output_data (4, dtd->dtd_data.ctti_name, "btt_name");
> dw2_asm_output_data (4, BTF_TYPE_INFO (btf_kind, btf_kflag, btf_vlen),
> "btt_info: kind=%u, kflag=%u, vlen=%u",
> @@ -634,6 +645,7 @@ btf_asm_type (ctf_container_ref ctfc, ctf_dtdef_ref dtd)
> case BTF_KIND_UNION:
> case BTF_KIND_ENUM:
> case BTF_KIND_DATASEC:
> + case BTF_KIND_ENUM64:
> dw2_asm_output_data (4, dtd->dtd_data.ctti_size, "btt_size: %uB",
> dtd->dtd_data.ctti_size);
> return;
> @@ -707,13 +719,13 @@ btf_asm_sou_member (ctf_container_ref ctfc, ctf_dmdef_t
> * dmd)
> }
> }
>
> -/* Asm'out an enum constant following a BTF_KIND_ENUM. */
> +/* Asm'out an enum constant following a BTF_KIND_ENUM{,64}. */
>
> static void
> -btf_asm_enum_const (ctf_dmdef_t * dmd)
> +btf_asm_enum_const (unsigned int size, ctf_dmdef_t * dmd)
> {
> dw2_asm_output_data (4, dmd->dmd_name_offset, "bte_name");
> - dw2_asm_output_data (4, dmd->dmd_value, "bte_value");
> + dw2_asm_output_data (size, dmd->dmd_value, "bte_value");
> }
>
> /* Asm'out a function parameter description following a BTF_KIND_FUNC_PROTO.
> */
> @@ -871,7 +883,7 @@ output_asm_btf_sou_fields (ctf_container_ref ctfc,
> ctf_dtdef_ref dtd)
> btf_asm_sou_member (ctfc, dmd);
> }
>
> -/* Output all enumerator constants following a BTF_KIND_ENUM. */
> +/* Output all enumerator constants following a BTF_KIND_ENUM{,64}. */
>
> static void
> output_asm_btf_enum_list (ctf_container_ref ARG_UNUSED (ctfc),
> @@ -881,7 +893,7 @@ output_asm_btf_enum_list (ctf_container_ref ARG_UNUSED
> (ctfc),
>
> for (dmd = dtd->dtd_u.dtu_members;
> dmd != NULL; dmd = (ctf_dmdef_t *) ctf_dmd_list_next (dmd))
> - btf_asm_enum_const (dmd);
> + btf_asm_enum_const (dtd->dtd_data.ctti_size, dmd);
> }
>
> /* Output all function arguments following a BTF_KIND_FUNC_PROTO. */
> diff --git a/gcc/ctfc.cc b/gcc/ctfc.cc
> index 9773358a475..253c36b6a0a 100644
> --- a/gcc/ctfc.cc
> +++ b/gcc/ctfc.cc
> @@ -604,6 +604,7 @@ ctf_add_enum (ctf_container_ref ctfc, uint32_t flag,
> const char * name,
> gcc_assert (size <= CTF_MAX_SIZE);
>
> dtd->dtd_data.ctti_size = size;
> + dtd->flags = CTF_ENUM_F_NONE;
>
> ctfc->ctfc_num_stypes++;
>
> @@ -612,7 +613,7 @@ ctf_add_enum (ctf_container_ref ctfc, uint32_t flag,
> const char * name,
>
> int
> ctf_add_enumerator (ctf_container_ref ctfc, ctf_id_t enid, const char * name,
> - HOST_WIDE_INT value, dw_die_ref die)
> + HOST_WIDE_INT value, uint32_t flags, dw_die_ref die)
> {
> ctf_dmdef_t * dmd;
> uint32_t kind, vlen, root;
> @@ -630,10 +631,12 @@ ctf_add_enumerator (ctf_container_ref ctfc, ctf_id_t
> enid, const char * name,
>
> gcc_assert (kind == CTF_K_ENUM && vlen < CTF_MAX_VLEN);
>
> - /* Enum value is of type HOST_WIDE_INT in the compiler, dmd_value is
> int32_t
> - on the other hand. Check bounds and skip adding this enum value if out
> of
> - bounds. */
> - if ((value > INT_MAX) || (value < INT_MIN))
> + /* Enum value is of type HOST_WIDE_INT in the compiler, CTF enumerators
> + values in ctf_enum_t is limited to int32_t, BTF supports signed and
> + unsigned enumerators values of 32 and 64 bits, for both debug formats
> + we use ctf_dmdef_t.dmd_value entry of HOST_WIDE_INT type. So check
> + CTF bounds and skip adding this enum value if out of bounds. */
> + if (!btf_debuginfo_p() && ((value > INT_MAX) || (value < INT_MIN)))
> {
> /* FIXME - Note this TBD_CTF_REPRESENTATION_LIMIT. */
> return (1);
> @@ -649,6 +652,7 @@ ctf_add_enumerator (ctf_container_ref ctfc, ctf_id_t
> enid, const char * name,
> dmd->dmd_value = value;
>
> dtd->dtd_data.ctti_info = CTF_TYPE_INFO (kind, root, vlen + 1);
> + dtd->flags |= flags;
> ctf_dmd_list_append (&dtd->dtd_u.dtu_members, dmd);
>
> if ((name != NULL) && strcmp (name, ""))
> diff --git a/gcc/ctfc.h b/gcc/ctfc.h
> index bcf3a43ae1b..a22342b2610 100644
> --- a/gcc/ctfc.h
> +++ b/gcc/ctfc.h
> @@ -125,6 +125,10 @@ typedef struct GTY (()) ctf_itype
>
> #define CTF_FUNC_VARARG 0x1
>
> +/* Enum specific flags. */
> +#define CTF_ENUM_F_NONE (0)
> +#define CTF_ENUM_F_ENUMERATORS_SIGNED (1 << 0)
> +
> /* Struct/union/enum member definition for CTF generation. */
>
> typedef struct GTY ((chain_next ("%h.dmd_next"))) ctf_dmdef
> @@ -133,7 +137,7 @@ typedef struct GTY ((chain_next ("%h.dmd_next")))
> ctf_dmdef
> ctf_id_t dmd_type; /* Type of this member (for sou). */
> uint32_t dmd_name_offset; /* Offset of the name in str table. */
> uint64_t dmd_offset; /* Offset of this member in bits (for
> sou). */
> - int dmd_value; /* Value of this member (for enum). */
> + HOST_WIDE_INT dmd_value; /* Value of this member (for enum). */
> struct ctf_dmdef * dmd_next; /* A list node. */
> } ctf_dmdef_t;
>
> @@ -162,6 +166,7 @@ struct GTY ((for_user)) ctf_dtdef
> bool from_global_func; /* Whether this type was added from a global
> function. */
> uint32_t linkage; /* Used in function types. 0=local, 1=global.
> */
> + uint32_t flags; /* Flags to describe specific type's
> properties. */
> union GTY ((desc ("ctf_dtu_d_union_selector (&%1)")))
> {
> /* struct, union, or enum. */
> @@ -429,7 +434,7 @@ extern ctf_id_t ctf_add_sou (ctf_container_ref, uint32_t,
> const char *,
> uint32_t, size_t, dw_die_ref);
>
> extern int ctf_add_enumerator (ctf_container_ref, ctf_id_t, const char *,
> - HOST_WIDE_INT, dw_die_ref);
> + HOST_WIDE_INT, uint32_t, dw_die_ref);
> extern int ctf_add_member_offset (ctf_container_ref, dw_die_ref, const char
> *,
> ctf_id_t, uint64_t);
> extern int ctf_add_function_arg (ctf_container_ref, dw_die_ref,
> diff --git a/gcc/dwarf2ctf.cc b/gcc/dwarf2ctf.cc
> index 397100004c2..0ef96dd48fd 100644
> --- a/gcc/dwarf2ctf.cc
> +++ b/gcc/dwarf2ctf.cc
> @@ -772,6 +772,7 @@ gen_ctf_enumeration_type (ctf_container_ref ctfc,
> dw_die_ref enumeration)
> const char *enumerator_name;
> dw_attr_node *enumerator_value;
> HOST_WIDE_INT value_wide_int;
> + uint32_t flags = 0;
>
> c = dw_get_die_sib (c);
>
> @@ -785,10 +786,14 @@ gen_ctf_enumeration_type (ctf_container_ref ctfc,
> dw_die_ref enumeration)
> == dw_val_class_unsigned_const_implicit))
> value_wide_int = AT_unsigned (enumerator_value);
> else
> - value_wide_int = AT_int (enumerator_value);
> + {
> + value_wide_int = AT_int (enumerator_value);
> + flags |= CTF_ENUM_F_ENUMERATORS_SIGNED;
> + }
>
> ctf_add_enumerator (ctfc, enumeration_type_id,
> - enumerator_name, value_wide_int, enumeration);
> + enumerator_name, value_wide_int,
> + flags, enumeration);
> }
> while (c != dw_get_die_child (enumeration));
> }
> diff --git a/gcc/testsuite/gcc.dg/debug/btf/btf-enum-1.c
> b/gcc/testsuite/gcc.dg/debug/btf/btf-enum-1.c
> index 728493b0804..7e940529f1b 100644
> --- a/gcc/testsuite/gcc.dg/debug/btf/btf-enum-1.c
> +++ b/gcc/testsuite/gcc.dg/debug/btf/btf-enum-1.c
> @@ -4,7 +4,7 @@
> /* { dg-options "-O0 -gbtf -dA" } */
>
> /* { dg-final { scan-assembler-times "\[\t \]0x6000004\[\t
> \]+\[^\n\]*btt_info" 1 } } */
> -/* { dg-final { scan-assembler-times "\[\t \]0x6000003\[\t
> \]+\[^\n\]*btt_info" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]0x86000003\[\t
> \]+\[^\n\]*btt_info" 1 } } */
> /* { dg-final { scan-assembler-times "ascii \"QAD.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> /* { dg-final { scan-assembler-times "ascii \"QED.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> /* { dg-final { scan-assembler-times "ascii \"QOD.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> diff --git a/gcc/testsuite/gcc.dg/debug/btf/btf-enum64-1.c
> b/gcc/testsuite/gcc.dg/debug/btf/btf-enum64-1.c
> new file mode 100644
> index 00000000000..da103842807
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/debug/btf/btf-enum64-1.c
> @@ -0,0 +1,41 @@
> +/* Test BTF generation for 64 bits enums. */
> +
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -gbtf -dA" } */
> +
> +/* { dg-final { scan-assembler-times "\[\t \].size\[\t \]myenum1,\[\t \]8" 1
> } } */
> +/* { dg-final { scan-assembler-times "\[\t \].size\[\t \]myenum2,\[\t \]8" 1
> } } */
> +/* { dg-final { scan-assembler-times "\[\t \].size\[\t \]myenum3,\[\t \]8" 1
> } } */
> +/* { dg-final { scan-assembler-times "\[\t \]0x13000003\[\t
> \]+\[^\n\]*btt_info" 2 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]0x93000003\[\t
> \]+\[^\n\]*btt_info" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"B1.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"B2.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"B3.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"C1.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"C2.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"C3.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"D1.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"D2.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"D3.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
> +/* { dg-final { scan-assembler-times "bte_value" 9 } } */
> +
> +enum default_enum
> +{
> + B1 = 0xffffffffaa,
> + B2 = 0xbbbbbbbb,
> + B3 = 0xaabbccdd,
> +} myenum1 = B1;
> +
> +enum explicit_unsigned
> +{
> + C1 = 0xffffffffbbUL,
> + C2 = 0xbbbbbbbb,
> + C3 = 0xaabbccdd,
> +} myenum2 = C1;
> +
> +enum signed64
> +{
> + D1 = 0xffffffffaa,
> + D2 = 0xbbbbbbbb,
> + D3 = -0x1,
> +} myenum3 = D1;
> diff --git a/include/btf.h b/include/btf.h
> index 78b551ced23..eba67f9d599 100644
> --- a/include/btf.h
> +++ b/include/btf.h
> @@ -109,7 +109,8 @@ struct btf_type
> #define BTF_KIND_VAR 14 /* Variable. */
> #define BTF_KIND_DATASEC 15 /* Section such as .bss or .data. */
> #define BTF_KIND_FLOAT 16 /* Floating point. */
> -#define BTF_KIND_MAX BTF_KIND_FLOAT
> +#define BTF_KIND_ENUM64 19 /* Enumeration up to 64 bits. */
> +#define BTF_KIND_MAX BTF_KIND_ENUM64
> #define NR_BTF_KINDS (BTF_KIND_MAX + 1)
>
> /* For some BTF_KINDs, struct btf_type is immediately followed by
> @@ -130,14 +131,17 @@ struct btf_type
> #define BTF_INT_BOOL (1 << 2)
>
> /* BTF_KIND_ENUM is followed by VLEN struct btf_enum entries,
> - which describe the enumerators. Note that BTF currently only
> - supports signed 32-bit enumerator values. */
> + which describe the enumerators. */
> struct btf_enum
> {
> uint32_t name_off; /* Offset in string section of enumerator name. */
> int32_t val; /* Enumerator value. */
> };
>
> +/* BTF_KF_ENUM_ holds the flags for kflags in BTF_KIND_ENUM{,64}. */
> +#define BTF_KF_ENUM_UNSIGNED (0)
> +#define BTF_KF_ENUM_SIGNED (1 << 0)
> +
> /* BTF_KIND_ARRAY is followed by a single struct btf_array. */
> struct btf_array
> {
> @@ -190,6 +194,15 @@ struct btf_var_secinfo
> uint32_t size; /* Size (in bytes) of variable. */
> };
>
> +/* BTF_KIND_ENUM64 is followed by VLEN struct btf_enum64 entries,
> + which describe the 64 bits enumerators. */
> +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 */
> +};
> +
> #ifdef __cplusplus
> }
> #endif
