From FEDORA_PATCHES Mon Sep 17 00:00:00 2001

From: Keith Seitz <keiths@redhat.com>

Date: Tue, 30 Jul 2019 10:46:38 -0700

Subject: gdb-sw24545-perf-regression.patch

;; Fix 8.3 symbol-reading performance regression

;; symtab/24545 (Tom de Vries)

commit e99f9db0f5211455ca4256e8db9d9081967d255e

Author: Tom de Vries <tdevries@suse.de>

Date:   Mon Jun 10 20:05:04 2019 +0200

    [gdb/symtab] Fix symbol loading performance regression

    The commit "[gdb/symtab] Fix language of duplicate static minimal symbol"

    introduces a performance regression, when loading a cc1 executable build with

    -O0 -g and gcc 7.4.0.  The performance regression, measured in 'real' time is

    about 175%.

    The slower execution comes from the fact that the fix in symbol_set_names

    makes the call to symbol_find_demangled_name unconditional.

    Fix this by reverting the commit, and redoing the fix as follows.

    Recapturing the original problem, the first time symbol_set_names is called

    with gsymbol.language == lang_auto and linkage_name == "_ZL3foov", the name is

    not present in the per_bfd->demangled_names_hash hash table, so

    symbol_find_demangled_name is called to demangle the name, after which the

    mangled/demangled pair is added to the hashtable.  The call to

    symbol_find_demangled_name also sets gsymbol.language to lang_cplus.

    The second time symbol_set_names is called with gsymbol.language == lang_auto

    and linkage_name == "_ZL3foov", the name is present in the hash table, so the

    demangled name from the hash table is used.  However, the language of the

    symbol remains lang_auto.

    Fix this by adding a field language in struct demangled_name_entry, and using

    the field in symbol_set_names to set the language of gsymbol, if necessary.

    Tested on x86_64-linux.

    gdb/ChangeLog:

    2019-06-10  Tom de Vries  <tdevries@suse.de>

            PR symtab/24545

            * symtab.c (struct demangled_name_entry): Add language field.

            (symbol_set_names):  Revert "[gdb/symtab] Fix language of duplicate

            static minimal symbol".  Set and use language field.

diff --git a/gdb/symtab.c b/gdb/symtab.c

--- a/gdb/symtab.c

+++ b/gdb/symtab.c

@@ -701,6 +701,7 @@ symbol_set_language (struct general_symbol_info *gsymbol,

 struct demangled_name_entry

 {

   const char *mangled;

+  ENUM_BITFIELD(language) language : LANGUAGE_BITS;

   char demangled[1];

 };

@@ -841,11 +842,6 @@ symbol_set_names (struct general_symbol_info *gsymbol,

   else

     linkage_name_copy = linkage_name;

-  /* Set the symbol language.  */

-  char *demangled_name_ptr

-    = symbol_find_demangled_name (gsymbol, linkage_name_copy);

-  gdb::unique_xmalloc_ptr<char> demangled_name (demangled_name_ptr);

-

   entry.mangled = linkage_name_copy;

   slot = ((struct demangled_name_entry **)

 	  htab_find_slot (per_bfd->demangled_names_hash,

@@ -858,6 +854,9 @@ symbol_set_names (struct general_symbol_info *gsymbol,

       || (gsymbol->language == language_go

 	  && (*slot)->demangled[0] == '\0'))

     {

+      char *demangled_name_ptr

+	= symbol_find_demangled_name (gsymbol, linkage_name_copy);

+      gdb::unique_xmalloc_ptr<char> demangled_name (demangled_name_ptr);

       int demangled_len = demangled_name ? strlen (demangled_name.get ()) : 0;

       /* Suppose we have demangled_name==NULL, copy_name==0, and

@@ -894,12 +893,16 @@ symbol_set_names (struct general_symbol_info *gsymbol,

 	  strcpy (mangled_ptr, linkage_name_copy);

 	  (*slot)->mangled = mangled_ptr;

 	}

+      (*slot)->language = gsymbol->language;

       if (demangled_name != NULL)

-	strcpy ((*slot)->demangled, demangled_name.get());

+	strcpy ((*slot)->demangled, demangled_name.get ());

       else

 	(*slot)->demangled[0] = '\0';

     }

+  else if (gsymbol->language == language_unknown

+	   || gsymbol->language == language_auto)

+    gsymbol->language = (*slot)->language;

   gsymbol->name = (*slot)->mangled;

   if ((*slot)->demangled[0] != '\0')