Changeset 50254 in webkit for trunk/JavaScriptCore/bytecode/CodeBlock.cpp

Timestamp:

Oct 28, 2009, 6:25:02 PM (16 years ago)

Author:

[email protected]

Message:

Improve for..in enumeration performance
​https://bugs.webkit.org/show_bug.cgi?id=30887

Reviewed by Geoff Garen.

Improve indexing of an object with a for..in iterator by
identifying cases where get_by_val is being used with a iterator
as the subscript and replace it with a new get_by_pname
bytecode. get_by_pname then optimizes lookups that directly access
the base object.

File:

• trunk/JavaScriptCore/bytecode/CodeBlock.cpp (modified) (2 diffs)

trunk/JavaScriptCore/bytecode/CodeBlock.cpp

@@ -825 +825 @@
             break;
         }
+        case op_get_by_pname: {
+            int r0 = (++it)->u.operand;
+            int r1 = (++it)->u.operand;
+            int r2 = (++it)->u.operand;
+            int r3 = (++it)->u.operand;
+            int r4 = (++it)->u.operand;
+            int r5 = (++it)->u.operand;
+            printf("[%4d] get_by_pname\t %s, %s, %s, %s, %s, %s\n", location, registerName(r0).c_str(), registerName(r1).c_str(), registerName(r2).c_str(), registerName(r3).c_str(), registerName(r4).c_str(), registerName(r5).c_str());
+            break;
+        }
         case op_put_by_val: {
             int r0 = (++it)->u.operand;
@@ -1016 +1026 @@
         }
         case op_get_pnames: {
-            int r0 = it[0].u.operand;
-            int r1 = it[1].u.operand;
-            printf("[%4d] get_pnames\t %s, %s\n", location, registerName(r0).c_str(), registerName(r1).c_str());
+            int r0 = it[1].u.operand;
+            int r1 = it[2].u.operand;
+            int r2 = it[3].u.operand;
+            int r3 = it[4].u.operand;
+            int offset = it[5].u.operand;
+            printf("[%4d] get_pnames\t %s, %s, %s, %s, %d(->%d)\n", location, registerName(r0).c_str(), registerName(r1).c_str(), registerName(r2).c_str(), registerName(r3).c_str(), offset, location + offset);
             it += OPCODE_LENGTH(op_get_pnames) - 1;
             break;
         }
         case op_next_pname: {
-            int dest = it[0].u.operand;
+            int dest = it[1].u.operand;
             int iter = it[4].u.operand;
             int offset = it[5].u.operand;