Hi Cuper.
OK. Hopefully all the roots are marked now to avoid these nodes being
collected.
Thanks.
> Hi everyone,
>
> This patch fixes BPF CO-RE builtins support that missed information for
> garbage collector (GC).
>
> The BPF CO-RE implementation defines several data structures that keep
> builtin information throught all of the compilation flow aside from
> code. This intentionally avoids having the builtin calls arguments
> expressions/enum/types tree nodes within the compiling code in order to
> avoid the compiler to optimize those away, based on information in
> current compilation unit.
> CO-RE builtins are target kernel specific and very little can be infered
> from type inforamtion within the compilation unit.
>
> Fault was triggered when attempting to compile some BPF kernel big
> examples that revealed the lack of GC information.
>
> Patch also removes some spurious includes of header files.
>
> Best regards,
> Cupertino
>
>
>
> commit c71b5c604189d04664c5b5ee155326fa4b79808b
> Author: Cupertino Miranda <cupertino.mira...@oracle.com>
> Date: Tue Aug 8 11:12:00 2023 +0100
>
> bpf: Fixed GC mistakes in BPF builtins code.
>
> This patches fixes problems with GC within the CO-RE builtins
> implementation.
> List of included headers was also reviseD.
>
> gcc/ChangeLog:
>
> * config/bpf/core-builtins.cc: Cleaned include headers.
> (struct cr_builtins): Added GTY.
> (cr_builtins_ref): Created.
> (builtins_data) Changed to GC root.
> (allocate_builtin_data): Changed.
> Included gt-core-builtins.h.
> * config/bpf/coreout.cc: (bpf_core_extra) Added GTY.
> (bpf_core_extra_ref): Created.
> (bpf_comment_info): Changed to GC root.
> (bpf_core_reloc_add, output_btfext_header, btf_ext_init): Changed.
>
> diff --git a/gcc/config/bpf/core-builtins.cc b/gcc/config/bpf/core-builtins.cc
> index 575e63d8ea77..c3222b4c7804 100644
> --- a/gcc/config/bpf/core-builtins.cc
> +++ b/gcc/config/bpf/core-builtins.cc
> @@ -22,52 +22,23 @@ along with GCC; see the file COPYING3. If not see
> #include "config.h"
> #include "system.h"
> #include "coretypes.h"
> -#include "tm.h"
> +#include "target.h"
> #include "rtl.h"
> -#include "regs.h"
> -#include "insn-config.h"
> -#include "insn-attr.h"
> -#include "recog.h"
> #include "output.h"
> -#include "alias.h"
> #include "tree.h"
> #include "stringpool.h"
> #include "attribs.h"
> -#include "varasm.h"
> -#include "stor-layout.h"
> -#include "calls.h"
> #include "function.h"
> -#include "explow.h"
> #include "memmodel.h"
> #include "emit-rtl.h"
> -#include "reload.h"
> -#include "tm_p.h"
> -#include "target.h"
> -#include "basic-block.h"
> #include "expr.h"
> -#include "optabs.h"
> -#include "bitmap.h"
> -#include "df.h"
> -#include "c-family/c-common.h"
> #include "diagnostic.h"
> -#include "builtins.h"
> -#include "predict.h"
> #include "langhooks.h"
> -#include "flags.h"
> -
> -#include "cfg.h"
> +#include "basic-block.h"
> #include "gimple.h"
> #include "gimple-iterator.h"
> #include "gimple-walk.h"
> #include "tree-pass.h"
> -#include "tree-iterator.h"
> -
> -#include "context.h"
> -#include "pass_manager.h"
> -
> -#include "gimplify.h"
> -#include "gimplify-me.h"
> -
> #include "plugin.h"
>
> #include "ctfc.h"
> @@ -159,37 +130,41 @@ along with GCC; see the file COPYING3. If not see
> as a builtin. */
>
>
> -struct cr_builtins
> +struct GTY(()) cr_builtins
> {
> tree type;
> tree expr;
> tree default_value;
> rtx rtx_default_value;
> - enum btf_core_reloc_kind kind; /* Recovered from proper argument. */
> + enum btf_core_reloc_kind kind;
> enum bpf_builtins orig_builtin_code;
> tree orig_arg_expr;
> };
> +typedef struct cr_builtins *cr_builtins_ref;
>
> #define CORE_BUILTINS_DATA_EMPTY \
> { NULL_TREE, NULL_TREE, NULL_TREE, NULL_RTX, BPF_RELO_INVALID, \
> BPF_BUILTIN_UNUSED, NULL }
>
> /* Vector definition and its access function. */
> -vec<struct cr_builtins> builtins_data;
> +static GTY(()) vec<cr_builtins_ref, va_gc> *builtins_data = NULL;
>
> static inline int
> allocate_builtin_data ()
> {
> - struct cr_builtins data = CORE_BUILTINS_DATA_EMPTY;
> - int ret = builtins_data.length ();
> - builtins_data.safe_push (data);
> + if (builtins_data == NULL)
> + vec_alloc (builtins_data, 1);
> +
> + cr_builtins_ref data = ggc_cleared_alloc<struct cr_builtins> ();
> + int ret = builtins_data->length ();
> + vec_safe_push (builtins_data, data);
> return ret;
> }
>
> static inline struct cr_builtins *
> get_builtin_data (int index)
> {
> - return &builtins_data[index];
> + return (*builtins_data)[index];
> }
>
> typedef bool
> @@ -200,11 +175,12 @@ search_builtin_data (builtin_local_data_compare_fn
> callback,
> struct cr_builtins *elem)
> {
> unsigned int i;
> - for (i = 0; i < builtins_data.length (); i++)
> - if ((callback != NULL && (callback) (elem, &builtins_data[i]))
> - || (callback == NULL
> - && (builtins_data[i].orig_arg_expr == elem->orig_arg_expr)))
> - return (int) i;
> + if(builtins_data != NULL)
> + for (i = 0; i < builtins_data->length (); i++)
> + if ((callback != NULL && (callback) (elem, (*builtins_data)[i]))
> + || (callback == NULL
> + && ((*builtins_data)[i]->orig_arg_expr == elem->orig_arg_expr)))
> + return (int) i;
>
> return -1;
> }
> @@ -1392,3 +1368,5 @@ bpf_replace_core_move_operands (rtx *operands)
> }
> }
> }
> +
> +#include "gt-core-builtins.h"
> diff --git a/gcc/config/bpf/coreout.cc b/gcc/config/bpf/coreout.cc
> index b84585fb104e..0c5d166298fb 100644
> --- a/gcc/config/bpf/coreout.cc
> +++ b/gcc/config/bpf/coreout.cc
> @@ -147,11 +147,12 @@ static char
> btf_ext_info_section_label[MAX_BTF_EXT_LABEL_BYTES];
>
> static GTY (()) vec<bpf_core_section_ref, va_gc> *bpf_core_sections;
>
> -struct bpf_core_extra {
> +struct GTY(()) bpf_core_extra {
> const char *accessor_str;
> tree type;
> };
> -static hash_map<bpf_core_reloc_ref, struct bpf_core_extra *>
> bpf_comment_info;
> +typedef struct bpf_core_extra *bpf_core_extra_ref;
> +static GTY(()) hash_map<bpf_core_reloc_ref, bpf_core_extra_ref>
> *bpf_comment_info;
>
> /* Create a new BPF CO-RE relocation record, and add it to the appropriate
> CO-RE section. */
> @@ -162,7 +163,7 @@ bpf_core_reloc_add (const tree type, const char *
> section_name,
> enum btf_core_reloc_kind kind)
> {
> bpf_core_reloc_ref bpfcr = ggc_cleared_alloc<bpf_core_reloc_t> ();
> - struct bpf_core_extra *info = ggc_cleared_alloc<struct bpf_core_extra> ();
> + bpf_core_extra_ref info = ggc_cleared_alloc<struct bpf_core_extra> ();
> ctf_container_ref ctfc = ctf_get_tu_ctfc ();
>
> /* Buffer the access string in the auxiliary strtab. */
> @@ -173,7 +174,7 @@ bpf_core_reloc_add (const tree type, const char *
> section_name,
>
> info->accessor_str = accessor;
> info->type = type;
> - bpf_comment_info.put (bpfcr, info);
> + bpf_comment_info->put (bpfcr, info);
>
> /* Add the CO-RE reloc to the appropriate section. */
> bpf_core_section_ref sec;
> @@ -288,7 +289,7 @@ output_btfext_header (void)
> static void
> output_asm_btfext_core_reloc (bpf_core_reloc_ref bpfcr)
> {
> - struct bpf_core_extra **info = bpf_comment_info.get (bpfcr);
> + bpf_core_extra_ref *info = bpf_comment_info->get (bpfcr);
> gcc_assert (info != NULL);
>
> bpfcr->bpfcr_astr_off += ctfc_get_strtab_len (ctf_get_tu_ctfc (),
> @@ -365,6 +366,7 @@ btf_ext_init (void)
> btf_ext_label_num++);
>
> vec_alloc (bpf_core_sections, 1);
> + bpf_comment_info = hash_map<bpf_core_reloc_ref,
> bpf_core_extra_ref>::create_ggc ();
> }
>
> /* Output the entire .BTF.ext section. */
