[PATCH 0/2] Remove cp_lookup_transparent_type

[PATCH 0/2] Remove cp_lookup_transparent_type

[Tom Tromey]

My notes have said for years that cp_lookup_transparent_type is
obsolete, and I've finally gotten around to removing it.

Regression tested on x86-64 Fedora 40.

Signed-off-by: Tom Tromey <tom@tromey.com>
---
Tom Tromey (2):
      Remove cp_lookup_transparent_type
      Remove lookup_transparent_type lang hook

 gdb/c-lang.c       |  8 ------
 gdb/cp-namespace.c | 78 ------------------------------------------------------
 gdb/cp-support.h   |  3 ---
 gdb/language.h     |  8 ------
 gdb/symtab.c       | 34 ++++++++----------------
 gdb/symtab.h       |  3 ---
 6 files changed, 11 insertions(+), 123 deletions(-)
---
base-commit: ec74e6871f4934fbdf661fde3be72fbf29db6c29
change-id: 20260121-cp-remove-junk-74b438f7e65d

Best regards,
-- 
Tom Tromey <tom@tromey.com>

[PATCH 1/2] Remove cp_lookup_transparent_type

[Tom Tromey]

cp_lookup_transparent_type seems to be a workaround for bugs in very
old compilers.  A comment mentions that the bugs are fixed in GCC 3.4
-- released in 2004.

I think this is long past due for removal, which this patch does.
---
 gdb/c-lang.c       |  8 ------
 gdb/cp-namespace.c | 78 ------------------------------------------------------
 gdb/cp-support.h   |  3 ---
 3 files changed, 89 deletions(-)

diff --git a/gdb/c-lang.c b/gdb/c-lang.c
index 8f5dcb0f29e..033a4b174e9 100644
--- a/gdb/c-lang.c
+++ b/gdb/c-lang.c
@@ -919,14 +919,6 @@ class cplus_language : public language_defn
     lai->set_bool_type (builtin->builtin_bool, "bool");
   }
 
-  /* See language.h.  */
-  struct type *lookup_transparent_type (const char *name,
-					domain_search_flags flags)
-    const override
-  {
-    return cp_lookup_transparent_type (name, flags);
-  }
-
   /* See language.h.  */
   unsigned int search_name_hash (const char *name) const override
   {
diff --git a/gdb/cp-namespace.c b/gdb/cp-namespace.c
index c7832088a91..2e3c539507c 100644
--- a/gdb/cp-namespace.c
+++ b/gdb/cp-namespace.c
@@ -44,10 +44,6 @@ static struct block_symbol
 			     const domain_search_flags domain,
 			     int basic_lookup, int is_in_anonymous);
 
-static struct type *cp_lookup_transparent_type_loop (const char *name,
-						     const char *scope,
-						     int scope_len);
-
 /* Check to see if SYMBOL refers to an object contained within an
    anonymous namespace; if so, add an appropriate using directive.  */
 
@@ -966,80 +962,6 @@ cp_lookup_nested_symbol (struct type *parent_type,
     }
 }
 
-/* The C++-version of lookup_transparent_type.  */
-
-/* FIXME: carlton/2004-01-16: The problem that this is trying to
-   address is that, unfortunately, sometimes NAME is wrong: it may not
-   include the name of namespaces enclosing the type in question.
-   lookup_transparent_type gets called when the type in question
-   is a declaration, and we're trying to find its definition; but, for
-   declarations, our type name deduction mechanism doesn't work.
-   There's nothing we can do to fix this in general, I think, in the
-   absence of debug information about namespaces (I've filed PR
-   gdb/1511 about this); until such debug information becomes more
-   prevalent, one heuristic which sometimes looks is to search for the
-   definition in namespaces containing the current namespace.
-
-   We should delete this functions once the appropriate debug
-   information becomes more widespread.  (GCC 3.4 will be the first
-   released version of GCC with such information.)  */
-
-struct type *
-cp_lookup_transparent_type (const char *name, domain_search_flags flags)
-{
-  /* First, try the honest way of looking up the definition.  */
-  struct type *t = basic_lookup_transparent_type (name, flags);
-  const char *scope;
-
-  if (t != NULL)
-    return t;
-
-  /* If that doesn't work and we're within a namespace, look there
-     instead.  */
-  const block *block = get_selected_block (0);
-  if (block == nullptr)
-    return nullptr;
-
-  scope = block->scope ();
-
-  if (scope[0] == '\0')
-    return NULL;
-
-  return cp_lookup_transparent_type_loop (name, scope, 0);
-}
-
-/* Lookup the type definition associated to NAME in namespaces/classes
-   containing SCOPE whose name is strictly longer than LENGTH.  LENGTH
-   must be the index of the start of a component of SCOPE.  */
-
-static struct type *
-cp_lookup_transparent_type_loop (const char *name,
-				 const char *scope,
-				 int length)
-{
-  int scope_length = length + cp_find_first_component (scope + length);
-  char *full_name;
-
-  /* If the current scope is followed by "::", look in the next
-     component.  */
-  if (scope[scope_length] == ':')
-    {
-      struct type *retval
-	= cp_lookup_transparent_type_loop (name, scope,
-					   scope_length + 2);
-
-      if (retval != NULL)
-	return retval;
-    }
-
-  full_name = (char *) alloca (scope_length + 2 + strlen (name) + 1);
-  strncpy (full_name, scope, scope_length);
-  memcpy (full_name + scope_length, "::", 2);
-  strcpy (full_name + scope_length + 2, name);
-
-  return basic_lookup_transparent_type (full_name);
-}
-
 /* This used to do something but was removed when it became
    obsolete.  */
 
diff --git a/gdb/cp-support.h b/gdb/cp-support.h
index c4579fe24c6..fb41a3c15b2 100644
--- a/gdb/cp-support.h
+++ b/gdb/cp-support.h
@@ -161,9 +161,6 @@ extern struct block_symbol
 			   const struct block *block,
 			   const domain_search_flags domain);
 
-struct type *cp_lookup_transparent_type (const char *name,
-					 domain_search_flags flags);
-
 /* See description in cp-namespace.c.  */
 
 struct type *cp_find_type_baseclass_by_name (struct type *parent_type,

-- 
2.49.0

[PATCH 2/2] Remove lookup_transparent_type lang hook

[Tom Tromey]

C++ was the only user of the lookup_transparent_type lang hook, so it
can be removed entirely.  basic_lookup_transparent_type and its helper
function are renamed as appropriate.
---
 gdb/language.h |  8 --------
 gdb/symtab.c   | 34 +++++++++++-----------------------
 gdb/symtab.h   |  3 ---
 3 files changed, 11 insertions(+), 34 deletions(-)

diff --git a/gdb/language.h b/gdb/language.h
index 50a4c026784..1a6420af74e 100644
--- a/gdb/language.h
+++ b/gdb/language.h
@@ -346,14 +346,6 @@ struct language_defn
   virtual void language_arch_info (struct gdbarch *,
 				   struct language_arch_info *) const = 0;
 
-  /* Find the definition of the type with the given name.  */
-
-  virtual struct type *lookup_transparent_type (const char *name,
-						domain_search_flags flags) const
-  {
-    return basic_lookup_transparent_type (name, flags);
-  }
-
   /* Find all symbols in the current program space matching NAME in
      DOMAIN, according to this language's rules.
 
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 63505a94d41..35e380980b5 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -2622,22 +2622,14 @@ symbol::matches (domain_search_flags flags) const
   return search_flags_matches (flags, m_domain);
 }
 
-/* See symtab.h.  */
-
-struct type *
-lookup_transparent_type (const char *name, domain_search_flags flags)
-{
-  return current_language->lookup_transparent_type (name, flags);
-}
-
-/* A helper for basic_lookup_transparent_type that interfaces with the
+/* A helper for lookup_transparent_type that interfaces with the
    "quick" symbol table functions.  */
 
 static struct type *
-basic_lookup_transparent_type_quick (struct objfile *objfile,
-				     enum block_enum block_index,
-				     domain_search_flags flags,
-				     const lookup_name_info &name)
+lookup_transparent_type_quick (struct objfile *objfile,
+			       enum block_enum block_index,
+			       domain_search_flags flags,
+			       const lookup_name_info &name)
 {
   struct compunit_symtab *cust;
   const struct blockvector *bv;
@@ -2658,14 +2650,10 @@ basic_lookup_transparent_type_quick (struct objfile *objfile,
   return sym->type ();
 }
 
-/* The standard implementation of lookup_transparent_type.  This code
-   was modeled on lookup_symbol -- the parts not relevant to looking
-   up types were just left out.  In particular it's assumed here that
-   types are available in STRUCT_DOMAIN and only in file-static or
-   global blocks.  */
+/* See symtab.h.  */
 
 struct type *
-basic_lookup_transparent_type (const char *name, domain_search_flags flags)
+lookup_transparent_type (const char *name, domain_search_flags flags)
 {
   struct type *t;
 
@@ -2674,8 +2662,8 @@ basic_lookup_transparent_type (const char *name, domain_search_flags flags)
   /* Search all the global symbols.  */
   for (objfile &objfile : current_program_space->objfiles ())
     {
-      t = basic_lookup_transparent_type_quick (&objfile, GLOBAL_BLOCK,
-					       flags, lookup_name);
+      t = lookup_transparent_type_quick (&objfile, GLOBAL_BLOCK,
+					 flags, lookup_name);
       if (t)
 	return t;
     }
@@ -2684,8 +2672,8 @@ basic_lookup_transparent_type (const char *name, domain_search_flags flags)
      but more useful than an error.  */
   for (objfile &objfile : current_program_space->objfiles ())
     {
-      t = basic_lookup_transparent_type_quick (&objfile, STATIC_BLOCK,
-					       flags, lookup_name);
+      t = lookup_transparent_type_quick (&objfile, STATIC_BLOCK,
+					 flags, lookup_name);
       if (t)
 	return t;
     }
diff --git a/gdb/symtab.h b/gdb/symtab.h
index bd305e5259c..6a1320aabad 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -2320,9 +2320,6 @@ extern void reread_symbols (int from_tty);
 extern struct type *lookup_transparent_type
     (const char *name, domain_search_flags flags = SEARCH_STRUCT_DOMAIN);
 
-extern struct type *basic_lookup_transparent_type
-     (const char *name, domain_search_flags flags = SEARCH_STRUCT_DOMAIN);
-
 /* Macro for name of symbol to indicate a file compiled with gcc.  */
 #ifndef GCC_COMPILED_FLAG_SYMBOL
 #define GCC_COMPILED_FLAG_SYMBOL "gcc_compiled."

-- 
2.49.0

Re: [PATCH 1/2] Remove cp_lookup_transparent_type

[Simon Marchi]

On 2026-01-21 19:51, Tom Tromey wrote:
> cp_lookup_transparent_type seems to be a workaround for bugs in very
> old compilers.  A comment mentions that the bugs are fixed in GCC 3.4
> -- released in 2004.
> 
> I think this is long past due for removal, which this patch does.

I don't have first hand experience with this, but yeah this comment
makes me confident that it is ok to remove:

   We should delete this functions once the appropriate debug
   information becomes more widespread.  (GCC 3.4 will be the first
   released version of GCC with such information.)

Approved-By: Simon Marchi <simon.marchi@efficios.com>

Simon

Re: [PATCH 2/2] Remove lookup_transparent_type lang hook

[Simon Marchi]

On 2026-01-21 19:51, Tom Tromey wrote:
> C++ was the only user of the lookup_transparent_type lang hook, so it
> can be removed entirely.  basic_lookup_transparent_type and its helper
> function are renamed as appropriate.

Approved-By: Simon Marchi <simon.marchi@efficios.com>

Simon