[binutils-gdb] [gdb/ada] Extend type equivalence test in ada_resolve_enum

[Tom de Vries]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=74c36641b0e997ce81294e5bd4fe2d2ce017ea57

commit 74c36641b0e997ce81294e5bd4fe2d2ce017ea57
Author: Tom de Vries <tdevries@suse.de>
Date:   Thu Sep 7 21:53:17 2023 +0200

    [gdb/ada] Extend type equivalence test in ada_resolve_enum
    
    When running test-case gdb.ada/local-enum.exp with target board debug-types, I
    run into:
    ...
    (gdb) print v1(three)^M
    No name 'three' in enumeration type 'local__e1'^M
    (gdb) FAIL: gdb.ada/local-enum.exp: print v1 element
    ...
    
    The array V1 is of type A1 which is an array with index type E1, containing
    "three" as enumerator:
    ...
      type E1 is (one, two, three);
      type A1 is array (E1) of Integer;
      V1 : A1 := (0, 1, 2);
    ...
    
    There's also a type E2 that contains three as enumerator:
    ...
      type E2 is (three, four, five);
    ...
    
    When doing "print v1(three)", it's the job of ada_resolve_enum to resolve
    "three" to type E1 rather than type E2.
    
    When using target board debug-types, the enums E1 and E2 are replicated in the
    .debug_types section, and consequently in ada_resolve_enum the type
    equivalence check using a pointer comparison fails:
    ...
      for (int i = 0; i < syms.size (); ++i)
        {
          /* We already know the name matches, so we're just looking for
             an element of the correct enum type.  */
          if (ada_check_typedef (syms[i].symbol->type ()) == context_type)
            return i;
        }
    ...
    
    Fix this by also trying a structural comparison using
    ada_identical_enum_types_p.
    
    Tested on x86_64-linux.
    
    Approved-By: Tom Tromey <tom@tromey.com>
    
    PR ada/29335
    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29335

Diff:
---
 gdb/ada-lang.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 2e1b9664fdc..2496c099f19 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -204,6 +204,8 @@ static symbol_name_matcher_ftype *ada_get_symbol_name_matcher
 
 static int symbols_are_identical_enums
   (const std::vector<struct block_symbol> &syms);
+
+static int ada_identical_enum_types_p (struct type *type1, struct type *type2);
 

 
 /* The character set used for source files.  */
@@ -3801,11 +3803,24 @@ ada_resolve_enum (std::vector<struct block_symbol> &syms,
   gdb_assert (context_type->code () == TYPE_CODE_ENUM);
   context_type = ada_check_typedef (context_type);
 
+  /* We already know the name matches, so we're just looking for
+     an element of the correct enum type.  */
+  struct type *type1 = context_type;
+  for (int i = 0; i < syms.size (); ++i)
+    {
+      struct type *type2 = ada_check_typedef (syms[i].symbol->type ());
+      if (type1 == type2)
+	return i;
+    }
+
   for (int i = 0; i < syms.size (); ++i)
     {
-      /* We already know the name matches, so we're just looking for
-	 an element of the correct enum type.  */
-      if (ada_check_typedef (syms[i].symbol->type ()) == context_type)
+      struct type *type2 = ada_check_typedef (syms[i].symbol->type ());
+      if (type1->num_fields () != type2->num_fields ())
+	continue;
+      if (strcmp (type1->name (), type2->name ()) != 0)
+	continue;
+      if (ada_identical_enum_types_p (type1, type2))
 	return i;
     }