[RFA 2/2] Simplify the psymbol hash function

[Tom Tromey <tom@tromey.com>]

This patch simplifies the psymbol_hash function, by changing it not to
examine the contents of the symbol's name.  This change just mirrors
what psymbol_compare already does -- it is checking for name equality,
which is presumably ok because symbol names are generally interned.

This change speeds up psymbol reading.  "gdb -nx -batch gdb"
previously took ~1.8 seconds on my machine, and with this patch it now
takes ~1.7 seconds.

gdb/ChangeLog
2017-11-04  Tom Tromey  <tom@tromey.com>

	* psymtab.c (psymbol_hash): Do not hash string contents.
---
 gdb/ChangeLog | 4 ++++
 gdb/psymtab.c | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index f848990867..d22f70a0c0 100644
--- a/gdb/psymtab.c
+++ b/gdb/psymtab.c
@@ -1515,7 +1515,7 @@ psymbol_hash (const void *addr, int length)
   h = hash_continue (&lang, sizeof (unsigned int), h);
   h = hash_continue (&domain, sizeof (unsigned int), h);
   h = hash_continue (&theclass, sizeof (unsigned int), h);
-  h = hash_continue (psymbol->ginfo.name, strlen (psymbol->ginfo.name), h);
+  h = hash_continue (&psymbol->ginfo.name, sizeof (psymbol->ginfo.name), h);
 
   return h;
 }
-- 
2.13.6