btf: Add support to BTF_KIND_ENUM64 type

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.

1 files changed, 16 insertions, 3 deletions

diff --git a/include/btf.h b/include/btf.h
index 78b551c..eba67f9 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