introduce minimal_symbol_upper_bound

This introduces minimal_symbol_upper_bound and changes various bits of
code to use it.  Since this function is intimately tied to the
implementation of minimal symbol tables, I believe it belongs in
minsyms.c.

The new function is extracted from find_pc_partial_function_gnu_ifunc.
This isn't a "clean" move because the old function interleaved the
caching and the computation; but this doesn't make sense for the new
code.

2014-02-26  Tom Tromey  <tromey@redhat.com>

	* blockframe.c (find_pc_partial_function_gnu_ifunc): Use
	bound minimal symbols.  Move code that knows about minsym
	table layout...
	* minsyms.c (minimal_symbol_upper_bound): ... here.  New
	function.
	* minsyms.h (minimal_symbol_upper_bound): Declare.
	* objc-lang.c (find_objc_msgsend): Use bound minimal symbols,
	minimal_symbol_upper_bound.

1 files changed, 12 insertions, 42 deletions

diff --git a/gdb/blockframe.c b/gdb/blockframe.c
index b03cd1b..014c45b 100644
--- a/gdb/blockframe.c
+++ b/gdb/blockframe.c
@@ -195,7 +195,7 @@ find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, const char **name,
 {
   struct obj_section *section;
   struct symbol *f;
-  struct minimal_symbol *msymbol;
+  struct bound_minimal_symbol msymbol;
   struct symtab *symtab = NULL;
   struct objfile *objfile;
   int i;
@@ -217,11 +217,11 @@ find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, const char **name,
       && section == cache_pc_function_section)
     goto return_cached_value;
 
-  msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section).minsym;
+  msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
   ALL_OBJFILES (objfile)
   {
     if (objfile->sf)
-      symtab = objfile->sf->qf->find_pc_sect_symtab (objfile, msymbol,
+      symtab = objfile->sf->qf->find_pc_sect_symtab (objfile, msymbol.minsym,
 						     mapped_pc, section, 0);
     if (symtab)
       break;
@@ -233,9 +233,9 @@ find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, const char **name,
 	 "pathological" case mentioned in print_frame_info.  */
       f = find_pc_sect_function (mapped_pc, section);
       if (f != NULL
-	  && (msymbol == NULL
+	  && (msymbol.minsym == NULL
 	      || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
-		  >= SYMBOL_VALUE_ADDRESS (msymbol))))
+		  >= SYMBOL_VALUE_ADDRESS (msymbol.minsym))))
 	{
 	  cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
 	  cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
@@ -252,10 +252,10 @@ find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, const char **name,
      last function in the text segment.  */
 
   if (!section)
-    msymbol = NULL;
+    msymbol.minsym = NULL;
 
   /* Must be in the minimal symbol table.  */
-  if (msymbol == NULL)
+  if (msymbol.minsym == NULL)
     {
       /* No available symbol.  */
       if (name != NULL)
@@ -269,42 +269,12 @@ find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, const char **name,
       return 0;
     }
 
-  cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
-  cache_pc_function_name = SYMBOL_LINKAGE_NAME (msymbol);
+  cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol.minsym);
+  cache_pc_function_name = SYMBOL_LINKAGE_NAME (msymbol.minsym);
   cache_pc_function_section = section;
-  cache_pc_function_is_gnu_ifunc = MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc;
-
-  /* If the minimal symbol has a size, use it for the cache.
-     Otherwise use the lesser of the next minimal symbol in the same
-     section, or the end of the section, as the end of the
-     function.  */
-
-  if (MSYMBOL_SIZE (msymbol) != 0)
-    cache_pc_function_high = cache_pc_function_low + MSYMBOL_SIZE (msymbol);
-  else
-    {
-      /* Step over other symbols at this same address, and symbols in
-	 other sections, to find the next symbol in this section with
-	 a different address.  */
-
-      for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
-	{
-	  if (SYMBOL_VALUE_ADDRESS (msymbol + i)
-	      != SYMBOL_VALUE_ADDRESS (msymbol)
-	      && SYMBOL_SECTION (msymbol + i)
-	      == SYMBOL_SECTION (msymbol))
-	    break;
-	}
-
-      if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
-	  && SYMBOL_VALUE_ADDRESS (msymbol + i)
-	  < obj_section_endaddr (section))
-	cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
-      else
-	/* We got the start address from the last msymbol in the objfile.
-	   So the end address is the end of the section.  */
-	cache_pc_function_high = obj_section_endaddr (section);
-    }
+  cache_pc_function_is_gnu_ifunc = (MSYMBOL_TYPE (msymbol.minsym)
+				    == mst_text_gnu_ifunc);
+  cache_pc_function_high = minimal_symbol_upper_bound (msymbol);
 
  return_cached_value: