[binutils-gdb] Only clear the minsym array when necessary

[binutils-gdb] Only clear the minsym array when necessary

[Christian Biesinger]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=808590ec5af20db08005885559fe29ebe7128b48

commit 808590ec5af20db08005885559fe29ebe7128b48
Author: Christian Biesinger <cbiesinger@google.com>
Date:   Tue Oct 29 17:14:48 2019 -0500

    Only clear the minsym array when necessary
    
    The array starts out initialized to zero:
      minimal_symbol *msymbol_hash[MINIMAL_SYMBOL_HASH_SIZE] {};
    
    So we only need to explicitly clear it if there were previous minsyms
    added to it. This patch does that.
    
    gdb/ChangeLog:
    
    2019-10-30  Christian Biesinger  <cbiesinger@google.com>
    
    	* minsyms.c (clear_minimal_symbol_hash_tables): New function.
    	(build_minimal_symbol_hash_tables): Code to clear the table moved
    	to clear_minimal_symbol_hash_tables.
    	(minimal_symbol_reader::install): Call clear_minimal_symbol_hash_tables
    	when needed.
    
    Change-Id: I7da994fe6747f67714e7efe9fdbb0dbc4d6ea532

Diff:
---
 gdb/ChangeLog |  8 ++++++++
 gdb/minsyms.c | 22 ++++++++++++++--------
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7338ec3..0382082 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2019-10-30  Christian Biesinger  <cbiesinger@google.com>
+
+	* minsyms.c (clear_minimal_symbol_hash_tables): New function.
+	(build_minimal_symbol_hash_tables): Code to clear the table moved
+	to clear_minimal_symbol_hash_tables.
+	(minimal_symbol_reader::install): Call clear_minimal_symbol_hash_tables
+	when needed.
+
 2019-10-29  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* infcmd.c: Remove includes.
diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index db3e546..78cb15b 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -1238,6 +1238,16 @@ compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
   return (mcount);
 }
 
+static void
+clear_minimal_symbol_hash_tables (struct objfile *objfile)
+{
+  for (size_t i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
+    {
+      objfile->per_bfd->msymbol_hash[i] = 0;
+      objfile->per_bfd->msymbol_demangled_hash[i] = 0;
+    }
+}
+
 /* Build (or rebuild) the minimal symbol hash tables.  This is necessary
    after compacting or sorting the table since the entries move around
    thus causing the internal minimal_symbol pointers to become jumbled.  */
@@ -1248,14 +1258,7 @@ build_minimal_symbol_hash_tables (struct objfile *objfile)
   int i;
   struct minimal_symbol *msym;
 
-  /* Clear the hash tables.  */
-  for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
-    {
-      objfile->per_bfd->msymbol_hash[i] = 0;
-      objfile->per_bfd->msymbol_demangled_hash[i] = 0;
-    }
-
-  /* Now, (re)insert the actual entries.  */
+  /* (Re)insert the actual entries.  */
   for ((i = objfile->per_bfd->minimal_symbol_count,
 	msym = objfile->per_bfd->msymbols.get ());
        i > 0;
@@ -1345,6 +1348,9 @@ minimal_symbol_reader::install ()
          The strings themselves are also located in the storage_obstack
          of this objfile.  */
 
+      if (m_objfile->per_bfd->minimal_symbol_count != 0)
+	clear_minimal_symbol_hash_tables (m_objfile);
+
       m_objfile->per_bfd->minimal_symbol_count = mcount;
       m_objfile->per_bfd->msymbols = std::move (msym_holder);