Avoid creating weak cells for literal arrays that are empty of literals.

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index 19de5d953f56c4b831afdfa7330666257f4c1d3b..68d9570d4fb6d90bd9eebe3f1ddb3b3f6c73f09d 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -1294,13 +1294,28 @@ void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
                               SharedFunctionInfo::kOffsetToPreviousOsrAstId));
   const int bailout_id = BailoutId::None().ToInt();
   __ Branch(&loop_bottom, ne, temp, Operand(Smi::FromInt(bailout_id)));
+
   // Literals available?
+  Label got_literals, maybe_cleared_weakcell;
   __ lw(temp, FieldMemOperand(array_pointer,
                               SharedFunctionInfo::kOffsetToPreviousLiterals));
+  // temp contains either a WeakCell pointing to the literals array or the
+  // literals array directly.
+  STATIC_ASSERT(WeakCell::kValueOffset == FixedArray::kLengthOffset);
+  __ lw(t0, FieldMemOperand(temp, WeakCell::kValueOffset));
+  __ JumpIfSmi(t0, &maybe_cleared_weakcell);
+  // t0 is a pointer, therefore temp is a WeakCell pointing to a literals array.
   __ lw(temp, FieldMemOperand(temp, WeakCell::kValueOffset));
-  __ JumpIfSmi(temp, &gotta_call_runtime);
+  __ jmp(&got_literals);
+
+  // t0 is a smi. If it's 0, then we are looking at a cleared WeakCell
+  // around the literals array, and we should visit the runtime. If it's > 0,
+  // then temp already contains the literals array.
+  __ bind(&maybe_cleared_weakcell);
+  __ Branch(&gotta_call_runtime, eq, t0, Operand(Smi::FromInt(0)));
 
   // Save the literals in the closure.
+  __ bind(&got_literals);
   __ lw(t0, MemOperand(sp, 0));
   __ sw(temp, FieldMemOperand(t0, JSFunction::kLiteralsOffset));
   __ push(index);