[gcc(refs/users/dfaust/heads/btf-type-tag-new-rebase)] include: Add BTF tag defines to dwarf2 and btf

[David Faust <dfaust@gcc.gnu.org>]

https://gcc.gnu.org/g:b6e7be91ec799f465f90c678bf4e1e8c4242a6b5

commit b6e7be91ec799f465f90c678bf4e1e8c4242a6b5
Author: David Faust <david.faust@oracle.com>
Date:   Wed Mar 2 14:59:35 2022 -0800

    include: Add BTF tag defines to dwarf2 and btf
    
    include/
    
            * btf.h: Add BTF_KIND_DECL_TAG and BTF_KIND_TYPE_TAG defines. Update
            comments.
            (struct btf_decl_tag): New.
            * dwarf2.def: Add new DWARF extension DW_TAG_GNU_annotation.

Diff:
---
 include/btf.h      | 17 +++++++++++++++--
 include/dwarf2.def |  4 ++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/btf.h b/include/btf.h
index 78b551ced23..37deaef8b48 100644
--- a/include/btf.h
+++ b/include/btf.h
@@ -69,7 +69,7 @@ struct btf_type
 
   /* SIZE is used by INT, ENUM, STRUCT, UNION, DATASEC kinds.
      TYPE is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, FUNC,
-     FUNC_PROTO and VAR kinds.  */
+     FUNC_PROTO, VAR and DECL_TAG kinds.  */
   union
   {
     uint32_t size;	/* Size of the entire type, in bytes.  */
@@ -109,7 +109,9 @@ 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_DECL_TAG	17	/* Decl Tag.  */
+#define BTF_KIND_TYPE_TAG	18	/* Type Tag.  */
+#define BTF_KIND_MAX		BTF_KIND_TYPE_TAG
 #define NR_BTF_KINDS		(BTF_KIND_MAX + 1)
 
 /* For some BTF_KINDs, struct btf_type is immediately followed by
@@ -190,6 +192,17 @@ struct btf_var_secinfo
   uint32_t size;	/* Size (in bytes) of variable.  */
 };
 
+/* BTF_KIND_DECL_TAG is followed by a single struct btf_decl_tag, which
+   describes the tag location:
+   - If component_idx == -1, then the tag is applied to a struct, union,
+     variable or function.
+   - Otherwise it is applied to a struct/union member or function argument
+     with the given given index numbered 0..vlen-1.  */
+struct btf_decl_tag
+{
+  int32_t component_idx;
+};
+
 #ifdef	__cplusplus
 }
 #endif
diff --git a/include/dwarf2.def b/include/dwarf2.def
index 530c6f849f9..a1f7a47a036 100644
--- a/include/dwarf2.def
+++ b/include/dwarf2.def
@@ -174,6 +174,10 @@ DW_TAG (DW_TAG_GNU_formal_parameter_pack, 0x4108)
    are properly part of DWARF 5.  */
 DW_TAG (DW_TAG_GNU_call_site, 0x4109)
 DW_TAG (DW_TAG_GNU_call_site_parameter, 0x410a)
+
+/* Extension for BTF annotations.  */
+DW_TAG (DW_TAG_GNU_annotation, 0x6000)
+
 /* Extensions for UPC.  See: http://dwarfstd.org/doc/DWARF4.pdf.  */
 DW_TAG (DW_TAG_upc_shared_type, 0x8765)
 DW_TAG (DW_TAG_upc_strict_type, 0x8766)