[PATCH 2/9] include: add BTF decl tag defines

[David Faust <david.faust@oracle.com>]

Add definitions for btf_decl_tag and the DW_TAG_GNU_annotation
DWARF extension.

include/

	* btf.h (struct btf_type): Update comment.
	(BTF_KIND_DECL_TAG): New define.
	(struct btf_decl_tag): New.
	* dwarf2.def (DW_TAG_GNU_annotation): New DW_TAG extension.
---
 include/btf.h      | 14 +++++++++++++-
 include/dwarf2.def |  4 ++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/include/btf.h b/include/btf.h
index d0994ab369b..bc808487ab8 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.  */
@@ -109,6 +109,7 @@ 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_DECL_TAG	17	/* Decl Tag.  */
 #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)
@@ -222,6 +223,17 @@ struct btf_enum64
   uint32_t val_hi32;	/* high 32-bit value for a 64-bit value Enumerator */
 };
 
+/* 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 7ab3ee611fd..4351498f288 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)
-- 
2.40.1