Backed out changeset 8401a2705903 (bug 1355046) for bug-1355046.js failures.

js/src/frontend/BytecodeEmitter.cpp

@@ -9134,6 +9134,8 @@ BytecodeEmitter::emitStatement(ParseNode* pn)
                     return false;
             }
         } else {
+            current->currentLine = parser.tokenStream().srcCoords.lineNum(pn2->pn_pos.begin);
+            current->lastColumn = 0;
             if (!reportExtraWarning(pn2, JSMSG_USELESS_EXPR))
                 return false;
         }

js/src/frontend/BytecodeEmitter.h

@@ -191,20 +191,9 @@ struct MOZ_STACK_CLASS BytecodeEmitter
         BytecodeVector code;        /* bytecode */
         SrcNotesVector notes;       /* source notes, see below */
         ptrdiff_t   lastNoteOffset; /* code offset for last source note */
-
-        // Line number for srcnotes.
-        //
-        // WARNING: If this becomes out of sync with already-emitted srcnotes,
-        // we can get undefined behavior.
-        uint32_t    currentLine;
-
-        // Zero-based column index on currentLine of last SRC_COLSPAN-annotated
-        // opcode.
-        //
-        // WARNING: If this becomes out of sync with already-emitted srcnotes,
-        // we can get undefined behavior.
-        uint32_t    lastColumn;
-
+        uint32_t    currentLine;    /* line number for tree-based srcnote gen */
+        uint32_t    lastColumn;     /* zero-based column index on currentLine of
+                                       last SRC_COLSPAN-annotated opcode */
         JumpTarget lastTarget;      // Last jump target emitted.
 
         EmitSection(JSContext* cx, uint32_t lineNum)

js/src/jit-test/tests/parser/bug-1355046.js

@@ -1,6 +0,0 @@
-var localstr = "";
-for (var i = 0; i < 0xFFFC; ++i)
-  localstr += ('\f') + i + "; ";
-var arg = "x";
-var body = localstr + "for (var i = 0; i < 4; ++i) arr[i](x-1);";
-(new Function(arg, body))(1000);