[PATCH v2 16/18] Optimize lookup_minimal_symbol_text

[Tom Tromey <tom@tromey.com>]

lookup_minimal_symbol_text always loops over all objfiles, even when
an objfile is passed in as an argument.  This patch changes the
function to loop over the minimal number of objfiles in the latter
situation.
---
 gdb/minsyms.c | 69 +++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 41 insertions(+), 28 deletions(-)

diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index 1d778822858..7e0522159b8 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -623,38 +623,51 @@ lookup_minimal_symbol_text (const char *name, struct objfile *objf)
 
   unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
 
-  for (objfile *objfile : current_program_space->objfiles ())
-    {
-      if (found_symbol.minsym != NULL)
-	break;
+  auto search = [&] (struct objfile *objfile)
+  {
+    for (msymbol = objfile->per_bfd->msymbol_hash[hash];
+	 msymbol != NULL && found_symbol.minsym == NULL;
+	 msymbol = msymbol->hash_next)
+      {
+	if (strcmp (msymbol->linkage_name (), name) == 0 &&
+	    (msymbol->type () == mst_text
+	     || msymbol->type () == mst_text_gnu_ifunc
+	     || msymbol->type () == mst_file_text))
+	  {
+	    switch (msymbol->type ())
+	      {
+	      case mst_file_text:
+		found_file_symbol.minsym = msymbol;
+		found_file_symbol.objfile = objfile;
+		break;
+	      default:
+		found_symbol.minsym = msymbol;
+		found_symbol.objfile = objfile;
+		break;
+	      }
+	  }
+      }
+  };
 
-      if (objf == NULL || objf == objfile
-	  || objf == objfile->separate_debug_objfile_backlink)
+  if (objf == nullptr)
+    {
+      for (objfile *objfile : current_program_space->objfiles ())
 	{
-	  for (msymbol = objfile->per_bfd->msymbol_hash[hash];
-	       msymbol != NULL && found_symbol.minsym == NULL;
-	       msymbol = msymbol->hash_next)
-	    {
-	      if (strcmp (msymbol->linkage_name (), name) == 0 &&
-		  (msymbol->type () == mst_text
-		   || msymbol->type () == mst_text_gnu_ifunc
-		   || msymbol->type () == mst_file_text))
-		{
-		  switch (msymbol->type ())
-		    {
-		    case mst_file_text:
-		      found_file_symbol.minsym = msymbol;
-		      found_file_symbol.objfile = objfile;
-		      break;
-		    default:
-		      found_symbol.minsym = msymbol;
-		      found_symbol.objfile = objfile;
-		      break;
-		    }
-		}
-	    }
+	  if (found_symbol.minsym != NULL)
+	    break;
+	  search (objfile);
 	}
     }
+  else
+    {
+      for (objfile *objfile : objf->separate_debug_objfiles ())
+	{
+	  if (found_symbol.minsym != NULL)
+	    break;
+	  search (objfile);
+	}
+    }
+
   /* External symbols are best.  */
   if (found_symbol.minsym)
     return found_symbol;

-- 
2.41.0