RFR(T): 8219554: Redundant lookup_common in SymbolTable::add

[Claes Redestad]

Hi,

the arguments passed to SymbolTable::add has already been through a call
to lookup_common, so a small optimization is to remove the redundant
call inside the add method:

- the lookup_common already done in the class file parser ensures none
of the symbols lives in the shared archive.
- do_add_if_needed will do a quick get into the dynamic hash table anyhow.

Bug:   https://bugs.openjdk.java.net/browse/JDK-8219554
Patch: [1]

Testing: tier1+2

Thanks!

/Claes

[1]
hg diff -r cc9359f8c563 src/hotspot/share/classfile/symbolTable.cpp
--- a/src/hotspot/share/classfile/symbolTable.cpp	Thu Feb 21 14:16:44 
2019 +0100
+++ b/src/hotspot/share/classfile/symbolTable.cpp	Thu Feb 21 23:12:29 
2019 +0100
@@ -444,10 +444,7 @@
      const char *name = names[i];
      int len = lengths[i];
      unsigned int hash = hashValues[i];
-    Symbol* sym = SymbolTable::the_table()->lookup_common(name, len, hash);
-    if (sym == NULL) {
-      sym = SymbolTable::the_table()->do_add_if_needed(name, len, hash, 
c_heap, CHECK);
-    }
+    Symbol* sym = SymbolTable::the_table()->do_add_if_needed(name, len, 
hash, c_heap, CHECK);
      assert(sym->refcount() != 0, "lookup should have incremented the 
count");
      cp->symbol_at_put(cp_indices[i], sym);
    }