[RFC 1/6] Defer minimal symbol name-setting

[Tom Tromey <tom@tromey.com>]

Currently the demangled name of a minimal symbol is set when creating
the symbol.  However, there is no intrinsic need to do this.  This
patch instead arranges for the demangling to be done just before the
minsym hash tables are filled.  This will be useful in a later patch.

gdb/ChangeLog
2019-03-03  Tom Tromey  <tom@tromey.com>

	* symtab.h (struct minimal_symbol) <name_set>: New member.
	* minsyms.c (minimal_symbol_reader::record_full): Copy name.
	Don't call symbol_set_names.
	(minimal_symbol_reader::install): Call symbol_set_names.
---
 gdb/ChangeLog |  7 +++++++
 gdb/minsyms.c | 18 +++++++++++++++++-
 gdb/symtab.h  |  4 ++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index 1b8e67bc98b..7872b7e2588 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -1145,7 +1145,11 @@ minimal_symbol_reader::record_full (const char *name, int name_len,
   msymbol = &m_msym_bunch->contents[m_msym_bunch_index];
   symbol_set_language (msymbol, language_auto,
 		       &m_objfile->per_bfd->storage_obstack);
-  symbol_set_names (msymbol, name, name_len, copy_name, m_objfile->per_bfd);
+
+  if (copy_name)
+    name = (char *) obstack_copy0 (&m_objfile->per_bfd->storage_obstack,
+				   name, name_len);
+  msymbol->name = name;
 
   SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
   MSYMBOL_SECTION (msymbol) = section;
@@ -1404,6 +1408,18 @@ minimal_symbol_reader::install ()
       m_objfile->per_bfd->minimal_symbol_count = mcount;
       m_objfile->per_bfd->msymbols = std::move (msym_holder);
 
+      msymbols = m_objfile->per_bfd->msymbols.get ();
+      for (int i = 0; i < mcount; ++i)
+	{
+	  if (!msymbols[i].name_set)
+	    {
+	      symbol_set_names (&msymbols[i], msymbols[i].name,
+				strlen (msymbols[i].name), 0,
+				m_objfile->per_bfd);
+	      msymbols[i].name_set = 1;
+	    }
+	}
+
       /* Now build the hash tables; we can't do this incrementally
          at an earlier point since we weren't finished with the obstack
 	 yet.  (And if the msymbol obstack gets moved, all the internal
diff --git a/gdb/symtab.h b/gdb/symtab.h
index 85dc3710483..29595685981 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -669,6 +669,10 @@ struct minimal_symbol : public general_symbol_info
      the object file format may not carry that piece of information.  */
   unsigned int has_size : 1;
 
+  /* Non-zero if this symbol ever had its demangled name set (even if
+     it was set to NULL).  */
+  unsigned int name_set : 1;
+
   /* Minimal symbols with the same hash key are kept on a linked
      list.  This is the link.  */
 
-- 
2.17.2