[gcc r12-1849] dwarf: externalize some DWARF internals for needs of CTF/BTF

[gcc r12-1849] dwarf: externalize some DWARF internals for needs of CTF/BTF

[Jose E. Marchesi]

https://gcc.gnu.org/g:5783a0cc78af95940dcb3d1a5d29041c3d8ae3e1

commit r12-1849-g5783a0cc78af95940dcb3d1a5d29041c3d8ae3e1
Author: Indu Bhagat <indu.bhagat@oracle.com>
Date:   Thu May 20 10:30:13 2021 -0700

    dwarf: externalize some DWARF internals for needs of CTF/BTF
    
    This patch externalizes some internal DIE structures and their attributes
    for the use of DWARF-based debug formats like CTF and BTF.
    
    The following functions which were previously defined as static in
    dwarf2out.c are now non-static, and extern prototypes for them have
    been added to dwarf2out.h:
    
    - get_AT
    - AT_int
    - AT_class
    - AT_loc
    - get_AT_ref
    - get_AT_string
    - get_AT_class
    - AT_unsigned
    - get_AT_unsigned
    - get_AT_flag
    - add_name_attribute
    - new_die_raw
    - base_type_die
    - lookup_decl_die
    - get_AT_file
    
    Note how this patch doens't change the names of these functions to
    avoid a massive renaming in dwarf2out.c, but in the future we probably
    want these functions to sport a dw_* prefix.
    
    Also, some type definitions have been moved from dwarf2out.c to
    dwarf2out.h:
    
    - dw_attr_node
    - struct dwarf_file_data
    
    Finally, three new accessor functions have been added to dwarf2out.c
    with prototypes in dwarf2out.h:
    
    - dw_get_die_child
    - dw_get_die_sib
    - dw_get_die_tag
    
    2021-06-28  Jose E. Marchesi  <jose.marchesi@oracle.com>
    
            * dwarf2out.c (AT_class): Function is no longer static.
            (AT_int): Likewise.
            (AT_unsigned): Likewise.
            (AT_loc): Likewise.
            (get_AT): Likewise.
            (get_AT_string): Likewise.
            (get_AT_flag): Likewise.
            (get_AT_unsigned): Likewise.
            (get_AT_ref): Likewise.
            (new_die_raw): Likewise.
            (lookup_decl_die): Likewise.
            (base_type_die): Likewise.
            (add_name_attribute): Likewise.
            (add_AT_int): Likewise.
            (add_AT_unsigned): Likewise.
            (add_AT_loc): Likewise.
            (dw_get_die_tag): New function.
            (dw_get_die_child): Likewise.
            (dw_get_die_sib): Likewise.
            (struct dwarf_file_data): Move from here to dwarf2out.h
            (struct dw_attr_struct): Likewise.
            * dwarf2out.h: Analogous changes.

Diff:
---
 gcc/dwarf2out.c | 81 +++++++++++++++++++++++++++------------------------------
 gcc/dwarf2out.h | 44 +++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+), 43 deletions(-)

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 9a91981acb0..e10006c5081 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -1332,12 +1332,6 @@ dwarf2out_switch_text_section (void)
 /* And now, the subset of the debugging information support code necessary
    for emitting location expressions.  */
 
-/* Data about a single source file.  */
-struct GTY((for_user)) dwarf_file_data {
-  const char * filename;
-  int emitted_number;
-};
-
 /* Describe an entry into the .debug_addr section.  */
 
 enum ate_kind {
@@ -3123,17 +3117,6 @@ maybe_reset_location_view (rtx_insn *insn, dw_line_info_table *table)
     RESET_NEXT_VIEW (table->view);
 }
 
-/* Each DIE attribute has a field specifying the attribute kind,
-   a link to the next attribute in the chain, and an attribute value.
-   Attributes are typically linked below the DIE they modify.  */
-
-typedef struct GTY(()) dw_attr_struct {
-  enum dwarf_attribute dw_attr;
-  dw_val_node dw_attr_val;
-}
-dw_attr_node;
-
-
 /* The Debugging Information Entry (DIE) structure.  DIEs form a tree.
    The children of each node form a circular list linked by
    die_sib.  die_child points to the node *before* the "first" child node.  */
@@ -3711,14 +3694,11 @@ static const char *dwarf_form_name (unsigned);
 static tree decl_ultimate_origin (const_tree);
 static tree decl_class_context (tree);
 static void add_dwarf_attr (dw_die_ref, dw_attr_node *);
-static inline enum dw_val_class AT_class (dw_attr_node *);
 static inline unsigned int AT_index (dw_attr_node *);
 static void add_AT_flag (dw_die_ref, enum dwarf_attribute, unsigned);
 static inline unsigned AT_flag (dw_attr_node *);
 static void add_AT_int (dw_die_ref, enum dwarf_attribute, HOST_WIDE_INT);
-static inline HOST_WIDE_INT AT_int (dw_attr_node *);
 static void add_AT_unsigned (dw_die_ref, enum dwarf_attribute, unsigned HOST_WIDE_INT);
-static inline unsigned HOST_WIDE_INT AT_unsigned (dw_attr_node *);
 static void add_AT_double (dw_die_ref, enum dwarf_attribute,
 			   HOST_WIDE_INT, unsigned HOST_WIDE_INT);
 static inline void add_AT_vec (dw_die_ref, enum dwarf_attribute, unsigned int,
@@ -3733,7 +3713,6 @@ static inline dw_die_ref AT_ref (dw_attr_node *);
 static inline int AT_ref_external (dw_attr_node *);
 static inline void set_AT_ref_external (dw_attr_node *, int);
 static void add_AT_loc (dw_die_ref, enum dwarf_attribute, dw_loc_descr_ref);
-static inline dw_loc_descr_ref AT_loc (dw_attr_node *);
 static void add_AT_loc_list (dw_die_ref, enum dwarf_attribute,
 			     dw_loc_list_ref);
 static inline dw_loc_list_ref AT_loc_list (dw_attr_node *);
@@ -3750,12 +3729,7 @@ static void add_AT_macptr (dw_die_ref, enum dwarf_attribute, const char *);
 static void add_AT_range_list (dw_die_ref, enum dwarf_attribute,
                                unsigned long, bool);
 static inline const char *AT_lbl (dw_attr_node *);
-static dw_attr_node *get_AT (dw_die_ref, enum dwarf_attribute);
 static const char *get_AT_low_pc (dw_die_ref);
-static const char *get_AT_string (dw_die_ref, enum dwarf_attribute);
-static int get_AT_flag (dw_die_ref, enum dwarf_attribute);
-static unsigned get_AT_unsigned (dw_die_ref, enum dwarf_attribute);
-static inline dw_die_ref get_AT_ref (dw_die_ref, enum dwarf_attribute);
 static bool is_c (void);
 static bool is_cxx (void);
 static bool is_cxx (const_tree);
@@ -3769,7 +3743,6 @@ static dw_die_ref lookup_type_die (tree);
 static dw_die_ref strip_naming_typedef (tree, dw_die_ref);
 static dw_die_ref lookup_type_die_strip_naming_typedef (tree);
 static void equate_type_number_to_die (tree, dw_die_ref);
-static dw_die_ref lookup_decl_die (tree);
 static var_loc_list *lookup_decl_loc (const_tree);
 static void equate_decl_number_to_die (tree, dw_die_ref);
 static struct var_loc_node *add_var_loc_to_decl (tree, rtx, const char *, var_loc_view);
@@ -3842,7 +3815,6 @@ static void output_ranges (void);
 static dw_line_info_table *new_line_info_table (void);
 static void output_line_info (bool);
 static void output_file_names (void);
-static dw_die_ref base_type_die (tree, bool);
 static int is_base_type (tree);
 static dw_die_ref subrange_type_die (tree, tree, tree, tree, dw_die_ref);
 static int decl_quals (const_tree);
@@ -3890,7 +3862,6 @@ static rtx rtl_for_decl_location (tree);
 static bool add_location_or_const_value_attribute (dw_die_ref, tree, bool);
 static bool tree_add_const_value_attribute (dw_die_ref, tree);
 static bool tree_add_const_value_attribute_for_decl (dw_die_ref, tree);
-static void add_name_attribute (dw_die_ref, const char *);
 static void add_desc_attribute (dw_die_ref, tree);
 static void add_gnat_descriptive_type_attribute (dw_die_ref, tree, dw_die_ref);
 static void add_comp_dir_attribute (dw_die_ref);
@@ -4497,7 +4468,7 @@ add_dwarf_attr (dw_die_ref die, dw_attr_node *attr)
   vec_safe_push (die->die_attr, *attr);
 }
 
-static inline enum dw_val_class
+enum dw_val_class
 AT_class (dw_attr_node *a)
 {
   return a->dw_attr_val.val_class;
@@ -4553,7 +4524,7 @@ add_AT_int (dw_die_ref die, enum dwarf_attribute attr_kind, HOST_WIDE_INT int_va
   add_dwarf_attr (die, &attr);
 }
 
-static inline HOST_WIDE_INT
+HOST_WIDE_INT
 AT_int (dw_attr_node *a)
 {
   gcc_assert (a && (AT_class (a) == dw_val_class_const
@@ -4576,7 +4547,7 @@ add_AT_unsigned (dw_die_ref die, enum dwarf_attribute attr_kind,
   add_dwarf_attr (die, &attr);
 }
 
-static inline unsigned HOST_WIDE_INT
+unsigned HOST_WIDE_INT
 AT_unsigned (dw_attr_node *a)
 {
   gcc_assert (a && (AT_class (a) == dw_val_class_unsigned_const
@@ -4960,7 +4931,7 @@ add_AT_loc (dw_die_ref die, enum dwarf_attribute attr_kind, dw_loc_descr_ref loc
   add_dwarf_attr (die, &attr);
 }
 
-static inline dw_loc_descr_ref
+dw_loc_descr_ref
 AT_loc (dw_attr_node *a)
 {
   gcc_assert (a && AT_class (a) == dw_val_class_loc);
@@ -5201,6 +5172,30 @@ index_addr_table_entry (addr_table_entry **h, unsigned int *index)
   return 1;
 }
 
+/* Return the tag of a given DIE.  */
+
+enum dwarf_tag
+dw_get_die_tag (dw_die_ref die)
+{
+  return die->die_tag;
+}
+
+/* Return a reference to the children list of a given DIE.  */
+
+dw_die_ref
+dw_get_die_child (dw_die_ref die)
+{
+  return die->die_child;
+}
+
+/* Return a reference to the sibling of a given DIE.  */
+
+dw_die_ref
+dw_get_die_sib (dw_die_ref die)
+{
+  return die->die_sib;
+}
+
 /* Add an address constant attribute value to a DIE.  When using
    dwarf_split_debug_info, address attributes in dies destined for the
    final executable should be direct references--setting the parameter
@@ -5398,7 +5393,7 @@ AT_lbl (dw_attr_node *a)
 
 /* Get the attribute of type attr_kind.  */
 
-static dw_attr_node *
+dw_attr_node *
 get_AT (dw_die_ref die, enum dwarf_attribute attr_kind)
 {
   dw_attr_node *a;
@@ -5453,7 +5448,7 @@ get_AT_low_pc (dw_die_ref die)
 /* Return the value of the string attribute designated by ATTR_KIND, or
    NULL if it is not present.  */
 
-static inline const char *
+const char *
 get_AT_string (dw_die_ref die, enum dwarf_attribute attr_kind)
 {
   dw_attr_node *a = get_AT (die, attr_kind);
@@ -5464,7 +5459,7 @@ get_AT_string (dw_die_ref die, enum dwarf_attribute attr_kind)
 /* Return the value of the flag attribute designated by ATTR_KIND, or -1
    if it is not present.  */
 
-static inline int
+int
 get_AT_flag (dw_die_ref die, enum dwarf_attribute attr_kind)
 {
   dw_attr_node *a = get_AT (die, attr_kind);
@@ -5475,7 +5470,7 @@ get_AT_flag (dw_die_ref die, enum dwarf_attribute attr_kind)
 /* Return the value of the unsigned attribute designated by ATTR_KIND, or 0
    if it is not present.  */
 
-static inline unsigned
+unsigned
 get_AT_unsigned (dw_die_ref die, enum dwarf_attribute attr_kind)
 {
   dw_attr_node *a = get_AT (die, attr_kind);
@@ -5483,7 +5478,7 @@ get_AT_unsigned (dw_die_ref die, enum dwarf_attribute attr_kind)
   return a ? AT_unsigned (a) : 0;
 }
 
-static inline dw_die_ref
+dw_die_ref
 get_AT_ref (dw_die_ref die, enum dwarf_attribute attr_kind)
 {
   dw_attr_node *a = get_AT (die, attr_kind);
@@ -5491,7 +5486,7 @@ get_AT_ref (dw_die_ref die, enum dwarf_attribute attr_kind)
   return a ? AT_ref (a) : NULL;
 }
 
-static inline struct dwarf_file_data *
+struct dwarf_file_data *
 get_AT_file (dw_die_ref die, enum dwarf_attribute attr_kind)
 {
   dw_attr_node *a = get_AT (die, attr_kind);
@@ -5776,7 +5771,7 @@ splice_child_die (dw_die_ref parent, dw_die_ref child)
 
 /* Create and return a new die with TAG_VALUE as tag.  */
  
-static inline dw_die_ref
+dw_die_ref
 new_die_raw (enum dwarf_tag tag_value)
 {
   dw_die_ref die = ggc_cleared_alloc<die_node> ();
@@ -5921,7 +5916,7 @@ decl_die_hasher::equal (die_node *x, tree y)
 
 /* Return the DIE associated with a given declaration.  */
 
-static inline dw_die_ref
+dw_die_ref
 lookup_decl_die (tree decl)
 {
   dw_die_ref *die = decl_die_table->find_slot_with_hash (decl, DECL_UID (decl),
@@ -13150,7 +13145,7 @@ need_endianity_attribute_p (bool reverse)
    This routine must only be called for GCC type nodes that correspond to
    Dwarf base (fundamental) types.  */
 
-static dw_die_ref
+dw_die_ref
 base_type_die (tree type, bool reverse)
 {
   dw_die_ref base_type_result;
@@ -20994,7 +20989,7 @@ compute_frame_pointer_to_fb_displacement (poly_int64 offset)
 /* Generate a DW_AT_name attribute given some string value to be included as
    the value of the attribute.  */
 
-static void
+void
 add_name_attribute (dw_die_ref die, const char *name_string)
 {
   if (name_string != NULL && *name_string != 0)
diff --git a/gcc/dwarf2out.h b/gcc/dwarf2out.h
index 54b6343704c..057afdb53a0 100644
--- a/gcc/dwarf2out.h
+++ b/gcc/dwarf2out.h
@@ -387,4 +387,48 @@ struct fixed_point_type_info
 
 void dwarf2out_c_finalize (void);
 
+/* Some DWARF internals are exposed for the needs of DWARF-based debug
+   formats.  */
+
+/* Each DIE attribute has a field specifying the attribute kind,
+   a link to the next attribute in the chain, and an attribute value.
+   Attributes are typically linked below the DIE they modify.  */
+
+typedef struct GTY(()) dw_attr_struct {
+  enum dwarf_attribute dw_attr;
+  dw_val_node dw_attr_val;
+}
+dw_attr_node;
+
+extern dw_attr_node *get_AT (dw_die_ref, enum dwarf_attribute);
+extern HOST_WIDE_INT AT_int (dw_attr_node *);
+extern unsigned HOST_WIDE_INT AT_unsigned (dw_attr_node *a);
+extern dw_loc_descr_ref AT_loc (dw_attr_node *);
+extern dw_die_ref get_AT_ref (dw_die_ref, enum dwarf_attribute);
+extern const char *get_AT_string (dw_die_ref, enum dwarf_attribute);
+extern enum dw_val_class AT_class (dw_attr_node *);
+extern unsigned HOST_WIDE_INT AT_unsigned (dw_attr_node *);
+extern unsigned get_AT_unsigned (dw_die_ref, enum dwarf_attribute);
+extern int get_AT_flag (dw_die_ref, enum dwarf_attribute);
+
+extern void add_name_attribute (dw_die_ref, const char *);
+
+extern dw_die_ref new_die_raw (enum dwarf_tag);
+extern dw_die_ref base_type_die (tree, bool);
+
+extern dw_die_ref lookup_decl_die (tree);
+
+extern dw_die_ref dw_get_die_child (dw_die_ref);
+extern dw_die_ref dw_get_die_sib (dw_die_ref);
+extern enum dwarf_tag dw_get_die_tag (dw_die_ref);
+
+/* Data about a single source file.  */
+struct GTY((for_user)) dwarf_file_data {
+  const char * filename;
+  int emitted_number;
+};
+
+extern struct dwarf_file_data *get_AT_file (dw_die_ref,
+					    enum dwarf_attribute);
+
 #endif /* GCC_DWARF2OUT_H */