[PATCH] RISC-V/objdump: Do not re-seacrh for mapping symbols when didn't find any.

[dmitry.bushev@syntacore.com]

From: Dmitry Bushev <dmitry.bushev@syntacore.com>

In object files without any mapping symbols it's better to not
search up to start of a section upon each instruction entry. Instead,
cache symbol number from which search was started and if no symbol found,
next time do not search past that symbol.

Signed-off-by: Dmitry Bushev <dmitry.bushev@syntacore.com>
---
 opcodes/riscv-dis.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/opcodes/riscv-dis.c b/opcodes/riscv-dis.c
index 8ab138e45ce..c754e1d9460 100644
--- a/opcodes/riscv-dis.c
+++ b/opcodes/riscv-dis.c
@@ -69,6 +69,7 @@ struct riscv_private_data
 /* Used for mapping symbols.  */
 static int last_map_symbol = -1;
 static bfd_vma last_stop_offset = 0;
+static int no_mapping_symbols_before = 0;
 static bfd_vma last_map_symbol_boundary = 0;
 static enum riscv_seg_mstate last_map_state = MAP_NONE;
 static asection *last_map_section = NULL;
@@ -1136,7 +1137,10 @@ riscv_search_mapping_symbol (bfd_vma memaddr,
 
   /* Reset the last_map_symbol if we start to dump a new section.  */
   if (memaddr <= 0)
-    last_map_symbol = -1;
+    {
+      last_map_symbol = -1;
+      no_mapping_symbols_before = 0;
+    }
 
   /* If the last stop offset is different from the current one, then
      don't use the last_map_symbol to search.  We usually reset the
@@ -1172,8 +1176,9 @@ riscv_search_mapping_symbol (bfd_vma memaddr,
   if (!found)
     {
       n = from_last_map_symbol ? last_map_symbol : info->symtab_pos;
+      int start_n = n;
 
-      for (; n >= 0; n--)
+      for (; n >= no_mapping_symbols_before; n--)
 	{
 	  bfd_vma addr = bfd_asymbol_value (info->symtab[n]);
 	  /* We have searched all possible symbols in the range.  */
@@ -1187,6 +1192,10 @@ riscv_search_mapping_symbol (bfd_vma memaddr,
 	      break;
 	    }
 	}
+      /* Remember that we already scanned all symbols before start_n and
+       * didn't find any. Next time, do not scan those symbols again. */
+      if (!found)
+	no_mapping_symbols_before = start_n;
     }
 
   if (found)
-- 
2.34.1