Revision: 11102
Author:   [email protected]
Date:     Wed Mar 21 02:52:17 2012
Log:      Version 3.9.23

Use correct arguments adaptation environment when inlining function containing arguments. (Issue 2014)

Performance and stability improvements on all platforms.
http://code.google.com/p/v8/source/detail?r=11102

Modified:
 /trunk/ChangeLog
 /trunk/src/builtins.cc
 /trunk/src/heap.cc
 /trunk/src/heap.h
 /trunk/src/hydrogen.cc
 /trunk/src/hydrogen.h
 /trunk/src/mips/builtins-mips.cc
 /trunk/src/mips/code-stubs-mips.cc
 /trunk/src/mips/debug-mips.cc
 /trunk/src/mips/ic-mips.cc
 /trunk/src/mips/lithium-codegen-mips.cc
 /trunk/src/mips/macro-assembler-mips.cc
 /trunk/src/mips/macro-assembler-mips.h
 /trunk/src/mips/simulator-mips.h
 /trunk/src/mips/stub-cache-mips.cc
 /trunk/src/objects.cc
 /trunk/src/runtime-profiler.cc
 /trunk/src/version.cc
 /trunk/test/cctest/test-heap-profiler.cc
 /trunk/test/cctest/test-log-stack-tracer.cc
 /trunk/test/mjsunit/compiler/inline-arguments.js

=======================================
--- /trunk/ChangeLog    Tue Mar 20 06:01:16 2012
+++ /trunk/ChangeLog    Wed Mar 21 02:52:17 2012
@@ -1,3 +1,11 @@
+2012-03-21: Version 3.9.23
+
+        Use correct arguments adaptation environment when inlining function
+        containing arguments. (Issue 2014)
+
+        Performance and stability improvements on all platforms.
+
+
 2012-03-20: Version 3.9.22

         Enabled count-based profiler by default.
=======================================
--- /trunk/src/builtins.cc      Mon Mar 19 04:01:52 2012
+++ /trunk/src/builtins.cc      Wed Mar 21 02:52:17 2012
@@ -33,6 +33,7 @@
 #include "builtins.h"
 #include "gdb-jit.h"
 #include "ic-inl.h"
+#include "heap-profiler.h"
 #include "mark-compact.h"
 #include "vm-state-inl.h"

@@ -380,6 +381,8 @@
MemoryChunk::IncrementLiveBytesFromMutator(elms->address(), -size_delta);
   }

+  HEAP_PROFILE(heap, ObjectMoveEvent(elms->address(),
+                                     elms->address() + size_delta));
   return FixedArray::cast(HeapObject::FromAddress(
       elms->address() + to_trim * kPointerSize));
 }
=======================================
--- /trunk/src/heap.cc  Mon Mar 19 04:01:52 2012
+++ /trunk/src/heap.cc  Wed Mar 21 02:52:17 2012
@@ -4812,13 +4812,56 @@
   }
   ASSERT(IsHeapIterable());
 }
+
+
+void Heap::AdvanceIdleIncrementalMarking(intptr_t step_size) {
+ // This flag prevents incremental marking from requesting GC via stack guard
+  idle_notification_will_schedule_next_gc_ = true;
+  incremental_marking()->Step(step_size);
+  idle_notification_will_schedule_next_gc_ = false;
+
+  if (incremental_marking()->IsComplete()) {
+    bool uncommit = false;
+    if (gc_count_at_last_idle_gc_ == gc_count_) {
+      // No GC since the last full GC, the mutator is probably not active.
+      isolate_->compilation_cache()->Clear();
+      uncommit = true;
+    }
+ CollectAllGarbage(kNoGCFlags, "idle notification: finalize incremental");
+    gc_count_at_last_idle_gc_ = gc_count_;
+    if (uncommit) {
+      new_space_.Shrink();
+      UncommitFromSpace();
+    }
+  }
+}


 bool Heap::IdleNotification(int hint) {
-  if (hint >= 1000) return IdleGlobalGC();
-  if (contexts_disposed_ > 0 || !FLAG_incremental_marking ||
+  intptr_t size_factor = Min(Max(hint, 30), 1000) / 10;
+  // The size factor is in range [3..100].
+ intptr_t step_size = size_factor * IncrementalMarking::kAllocatedThreshold;
+
+  if (contexts_disposed_ > 0) {
+    int mark_sweep_time = Min(TimeMarkSweepWouldTakeInMs(), 1000);
+    if (hint >= mark_sweep_time && !FLAG_expose_gc) {
+      HistogramTimerScope scope(isolate_->counters()->gc_context());
+      CollectAllGarbage(kReduceMemoryFootprintMask,
+                        "idle notification: contexts disposed");
+    } else {
+      AdvanceIdleIncrementalMarking(step_size);
+      contexts_disposed_ = 0;
+    }
+    // Make sure that we have no pending context disposals.
+ // Take into account that we might have decided to delay full collection
+    // because incremental marking is in progress.
+ ASSERT((contexts_disposed_ == 0) | | !incremental_marking()->IsStopped());
+    return false;
+  }
+
+  if (hint >= 1000 || !FLAG_incremental_marking ||
       FLAG_expose_gc || Serializer::enabled()) {
-    return true;
+    return IdleGlobalGC();
   }

   // By doing small chunks of GC work in each IdleNotification,
@@ -4830,9 +4873,6 @@
   // 3. many lazy sweep steps.
   // Use mark-sweep-compact events to count incremental GCs in a round.

-  intptr_t size_factor = Min(Max(hint, 30), 1000) / 10;
-  // The size factor is in range [3..100].
- intptr_t step_size = size_factor * IncrementalMarking::kAllocatedThreshold;

   if (incremental_marking()->IsStopped()) {
     if (!IsSweepingComplete() &&
@@ -4859,32 +4899,14 @@
   }

   if (incremental_marking()->IsStopped()) {
-    if (hint < 1000 && !WorthStartingGCWhenIdle()) {
+    if (!WorthStartingGCWhenIdle()) {
       FinishIdleRound();
       return true;
     }
     incremental_marking()->Start();
   }

- // This flag prevents incremental marking from requesting GC via stack guard
-  idle_notification_will_schedule_next_gc_ = true;
-  incremental_marking()->Step(step_size);
-  idle_notification_will_schedule_next_gc_ = false;
-
-  if (incremental_marking()->IsComplete()) {
-    bool uncommit = false;
-    if (gc_count_at_last_idle_gc_ == gc_count_) {
-      // No GC since the last full GC, the mutator is probably not active.
-      isolate_->compilation_cache()->Clear();
-      uncommit = true;
-    }
- CollectAllGarbage(kNoGCFlags, "idle notification: finalize incremental");
-    gc_count_at_last_idle_gc_ = gc_count_;
-    if (uncommit) {
-      new_space_.Shrink();
-      UncommitFromSpace();
-    }
-  }
+  AdvanceIdleIncrementalMarking(step_size);
   return false;
 }

@@ -4917,13 +4939,7 @@
   }

   if (number_idle_notifications_ == kIdlesBeforeScavenge) {
-    if (contexts_disposed_ > 0) {
-      HistogramTimerScope scope(isolate_->counters()->gc_context());
-      CollectAllGarbage(kReduceMemoryFootprintMask,
-                        "idle notification: contexts disposed");
-    } else {
-      CollectGarbage(NEW_SPACE, "idle notification");
-    }
+    CollectGarbage(NEW_SPACE, "idle notification");
     new_space_.Shrink();
     last_idle_notification_gc_count_ = gc_count_;
   } else if (number_idle_notifications_ == kIdlesBeforeMarkSweep) {
@@ -4942,23 +4958,6 @@
     last_idle_notification_gc_count_ = gc_count_;
     number_idle_notifications_ = 0;
     finished = true;
-  } else if (contexts_disposed_ > 0) {
-    if (FLAG_expose_gc) {
-      contexts_disposed_ = 0;
-    } else {
-      HistogramTimerScope scope(isolate_->counters()->gc_context());
-      CollectAllGarbage(kReduceMemoryFootprintMask,
-                        "idle notification: contexts disposed");
-      last_idle_notification_gc_count_ = gc_count_;
-    }
-    // If this is the first idle notification, we reset the
-    // notification count to avoid letting idle notifications for
-    // context disposal garbage collections start a potentially too
-    // aggressive idle GC cycle.
-    if (number_idle_notifications_ <= 1) {
-      number_idle_notifications_ = 0;
-      uncommit = false;
-    }
   } else if (number_idle_notifications_ > kIdlesBeforeMarkCompact) {
     // If we have received more than kIdlesBeforeMarkCompact idle
     // notifications we do not perform any cleanup because we don't
@@ -4966,11 +4965,6 @@
     finished = true;
   }

-  // Make sure that we have no pending context disposals and
-  // conditionally uncommit from space.
-  // Take into account that we might have decided to delay full collection
-  // because incremental marking is in progress.
-  ASSERT((contexts_disposed_ == 0) || !incremental_marking()->IsStopped());
   if (uncommit) UncommitFromSpace();

   return finished;
=======================================
--- /trunk/src/heap.h   Mon Mar 19 04:01:52 2012
+++ /trunk/src/heap.h   Wed Mar 21 02:52:17 2012
@@ -1965,10 +1965,25 @@
     }
     return incremental_marking()->WorthActivating();
   }
+
+  // Estimates how many milliseconds a Mark-Sweep would take to complete.
+  // In idle notification handler we assume that this function will return:
+  // - a number less than 10 for small heaps, which are less than 8Mb.
+ // - a number greater than 10 for large heaps, which are greater than 32Mb.
+  int TimeMarkSweepWouldTakeInMs() {
+ // Rough estimate of how many megabytes of heap can be processed in 1 ms.
+    static const int kMbPerMs = 2;
+
+    int heap_size_mb = static_cast<int>(SizeOfObjects() / MB);
+    return heap_size_mb / kMbPerMs;
+  }

   // Returns true if no more GC work is left.
   bool IdleGlobalGC();

+  void AdvanceIdleIncrementalMarking(intptr_t step_size);
+
+
   static const int kInitialSymbolTableSize = 2048;
   static const int kInitialEvalCacheSize = 64;
   static const int kInitialNumberStringCacheSize = 256;
=======================================
--- /trunk/src/hydrogen.cc      Tue Mar 20 06:01:16 2012
+++ /trunk/src/hydrogen.cc      Wed Mar 21 02:52:17 2012
@@ -4523,7 +4523,7 @@

 HInstruction* HGraphBuilder::BuildLoadNamedGeneric(HValue* obj,
                                                    Property* expr) {
-  if (expr->IsUninitialized()) {
+  if (expr->IsUninitialized() && !FLAG_always_opt) {
     AddInstruction(new(zone()) HSoftDeoptimize);
     current_block()->MarkAsDeoptimizing();
   }
@@ -5749,20 +5749,11 @@
         AddInstruction(new(zone()) HWrapReceiver(receiver, function));
     PushAndAdd(new(zone()) HPushArgument(wrapped_receiver));

-    int parameter_count = environment()->parameter_count();
-    for (int i = 1; i < environment()->parameter_count(); i++) {
-      PushAndAdd(new(zone()) HPushArgument(environment()->Lookup(i)));
-    }
-
-    if (environment()->outer()->frame_type() == ARGUMENTS_ADAPTOR) {
-      HEnvironment* adaptor = environment()->outer();
-      parameter_count = adaptor->parameter_count();
-
-      for (int i = environment()->parameter_count();
-           i < adaptor->parameter_count();
-           i++) {
-        PushAndAdd(new(zone()) HPushArgument(adaptor->Lookup(i)));
-      }
+    HEnvironment* arguments_env = environment()->arguments_environment();
+
+    int parameter_count = arguments_env->parameter_count();
+    for (int i = 1; i < arguments_env->parameter_count(); i++) {
+      PushAndAdd(new(zone()) HPushArgument(arguments_env->Lookup(i)));
     }

     HInvokeFunction* call = new(zone()) HInvokeFunction(
=======================================
--- /trunk/src/hydrogen.h       Mon Mar 19 04:01:52 2012
+++ /trunk/src/hydrogen.h       Wed Mar 21 02:52:17 2012
@@ -399,6 +399,10 @@
     if (drop_extra) outer->Drop(1);
     return outer;
   }
+
+  HEnvironment* arguments_environment() {
+    return outer()->frame_type() == ARGUMENTS_ADAPTOR ? outer() : this;
+  }

   // Simple accessors.
   Handle<JSFunction> closure() const { return closure_; }
=======================================
--- /trunk/src/mips/builtins-mips.cc    Fri Mar  9 02:52:05 2012
+++ /trunk/src/mips/builtins-mips.cc    Wed Mar 21 02:52:17 2012
@@ -67,9 +67,11 @@
     ASSERT(extra_args == NO_EXTRA_ARGUMENTS);
   }

-  // JumpToExternalReference expects a0 to contain the number of arguments
+  // JumpToExternalReference expects s0 to contain the number of arguments
   // including the receiver and the extra arguments.
-  __ Addu(a0, a0, Operand(num_extra_args + 1));
+  __ Addu(s0, a0, num_extra_args + 1);
+  __ sll(s1, s0, kPointerSizeLog2);
+  __ Subu(s1, s1, kPointerSize);
   __ JumpToExternalReference(ExternalReference(id, masm->isolate()));
 }

=======================================
--- /trunk/src/mips/code-stubs-mips.cc  Mon Mar 19 04:01:52 2012
+++ /trunk/src/mips/code-stubs-mips.cc  Wed Mar 21 02:52:17 2012
@@ -70,13 +70,13 @@
   // The ToNumber stub takes one argument in a0.
   Label check_heap_number, call_builtin;
   __ JumpIfNotSmi(a0, &check_heap_number);
+  __ Ret(USE_DELAY_SLOT);
   __ mov(v0, a0);
-  __ Ret();

   __ bind(&check_heap_number);
   EmitCheckForHeapNumber(masm, a0, a1, t0, &call_builtin);
+  __ Ret(USE_DELAY_SLOT);
   __ mov(v0, a0);
-  __ Ret();

   __ bind(&call_builtin);
   __ push(a0);
@@ -128,9 +128,9 @@
   // found in the shared function info object.
   __ lw(a3, FieldMemOperand(a3, SharedFunctionInfo::kCodeOffset));
   __ Addu(a3, a3, Operand(Code::kHeaderSize - kHeapObjectTag));
-  __ sw(a3, FieldMemOperand(v0, JSFunction::kCodeEntryOffset));

   // Return result. The argument function info has been popped already.
+  __ sw(a3, FieldMemOperand(v0, JSFunction::kCodeEntryOffset));
   __ Ret();

   // Create a new closure through the slower runtime call.
@@ -179,8 +179,7 @@

   // Remove the on-stack argument and return.
   __ mov(cp, v0);
-  __ Pop();
-  __ Ret();
+  __ DropAndRet(1);

   // Need to collect. Call into runtime system.
   __ bind(&gc);
@@ -242,8 +241,7 @@

   // Remove the on-stack argument and return.
   __ mov(cp, v0);
-  __ Addu(sp, sp, Operand(2 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(2);

   // Need to collect. Call into runtime system.
   __ bind(&gc);
@@ -368,8 +366,7 @@
   GenerateFastCloneShallowArrayCommon(masm, length_, mode, &slow_case);

   // Return and remove the on-stack parameters.
-  __ Addu(sp, sp, Operand(3 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(3);

   __ bind(&slow_case);
   __ TailCallRuntime(Runtime::kCreateArrayLiteralShallow, 3, 1);
@@ -405,16 +402,14 @@

   // Allocate the JS object and copy header together with all in-object
   // properties from the boilerplate.
-  __ AllocateInNewSpace(size, a0, a1, a2, &slow_case, TAG_OBJECT);
+  __ AllocateInNewSpace(size, v0, a1, a2, &slow_case, TAG_OBJECT);
   for (int i = 0; i < size; i += kPointerSize) {
     __ lw(a1, FieldMemOperand(a3, i));
-    __ sw(a1, FieldMemOperand(a0, i));
+    __ sw(a1, FieldMemOperand(v0, i));
   }

   // Return and remove the on-stack parameters.
-  __ Drop(4);
-  __ Ret(USE_DELAY_SLOT);
-  __ mov(v0, a0);
+  __ DropAndRet(4);

   __ bind(&slow_case);
   __ TailCallRuntime(Runtime::kCreateObjectLiteralShallow, 4, 1);
@@ -492,8 +487,8 @@
   __ Or(at, exponent, Operand(exponent_word_for_1));
   __ Movn(exponent, at, source_);  // Write exp when source not 0.
   // 1, 0 and -1 all have 0 for the second word.
+  __ Ret(USE_DELAY_SLOT);
   __ mov(mantissa, zero_reg);
-  __ Ret();

   __ bind(&not_special);
   // Count leading zeros.
@@ -514,9 +509,9 @@
   __ sll(mantissa, source_, HeapNumber::kMantissaBitsInTopWord);
   // And the top (top 20 bits).
   __ srl(source_, source_, 32 - HeapNumber::kMantissaBitsInTopWord);
-  __ or_(exponent, exponent, source_);
-
-  __ Ret();
+
+  __ Ret(USE_DELAY_SLOT);
+  __ or_(exponent, exponent, source_);
 }


@@ -1025,9 +1020,9 @@
__ sw(v0, FieldMemOperand(heap_number_result, HeapNumber::kMantissaOffset));
   }
// Place heap_number_result in v0 and return to the pushed return address.
-  __ mov(v0, heap_number_result);
   __ pop(ra);
-  __ Ret();
+  __ Ret(USE_DELAY_SLOT);
+  __ mov(v0, heap_number_result);
 }


@@ -1163,6 +1158,7 @@
   }

   __ bind(&return_equal);
+
   if (cc == less) {
     __ li(v0, Operand(GREATER));  // Things aren't less than themselves.
   } else if (cc == greater) {
@@ -1234,8 +1230,8 @@
   if (strict) {
// If lhs was not a number and rhs was a Smi then strict equality cannot
     // succeed. Return non-equal (lhs is already not zero).
+    __ Ret(USE_DELAY_SLOT, ne, t4, Operand(HEAP_NUMBER_TYPE));
     __ mov(v0, lhs);
-    __ Ret(ne, t4, Operand(HEAP_NUMBER_TYPE));
   } else {
     // Smi compared non-strictly with a non-Smi non-heap-number. Call
     // the runtime.
@@ -1273,8 +1269,8 @@
   if (strict) {
// If lhs was not a number and rhs was a Smi then strict equality cannot
     // succeed. Return non-equal.
+    __ Ret(USE_DELAY_SLOT, ne, t4, Operand(HEAP_NUMBER_TYPE));
     __ li(v0, Operand(1));
-    __ Ret(ne, t4, Operand(HEAP_NUMBER_TYPE));
   } else {
     // Smi compared non-strictly with a non-Smi non-heap-number. Call
     // the runtime.
@@ -1354,12 +1350,13 @@
   __ bind(&one_is_nan);
   // NaN comparisons always fail.
   // Load whatever we need in v0 to make the comparison fail.
+
   if (cc == lt || cc == le) {
     __ li(v0, Operand(GREATER));
   } else {
     __ li(v0, Operand(LESS));
   }
-  __ Ret();  // Return.
+  __ Ret();

   __ bind(&neither_is_nan);
 }
@@ -1408,6 +1405,7 @@
     __ Branch(&return_result_not_equal, ne, t4, Operand(zero_reg));

     __ bind(&return_result_equal);
+
     __ li(v0, Operand(EQUAL));
     __ Ret();
   }
@@ -1439,6 +1437,7 @@
     __ BranchF(&less_than, NULL, lt, f12, f14);

     // Not equal, not less, not NaN, must be greater.
+
     __ li(v0, Operand(GREATER));
     __ Ret();

@@ -1469,8 +1468,8 @@
     // Return non-zero.
     Label return_not_equal;
     __ bind(&return_not_equal);
+    __ Ret(USE_DELAY_SLOT);
     __ li(v0, Operand(1));
-    __ Ret();

     __ bind(&first_non_object);
     // Check for oddballs: true, false, null, undefined.
@@ -1549,8 +1548,8 @@

   // Both are symbols. We already checked they weren't the same pointer
   // so they are not equal.
+  __ Ret(USE_DELAY_SLOT);
   __ li(v0, Operand(1));   // Non-zero indicates not equal.
-  __ Ret();

   __ bind(&object_test);
   __ Branch(not_both_strings, lt, a2, Operand(FIRST_SPEC_OBJECT_TYPE));
@@ -1565,8 +1564,8 @@
   __ lbu(a3, FieldMemOperand(a3, Map::kBitFieldOffset));
   __ and_(a0, a2, a3);
   __ And(a0, a0, Operand(1 << Map::kIsUndetectable));
-  __ Xor(v0, a0, Operand(1 << Map::kIsUndetectable));
-  __ Ret();
+  __ Ret(USE_DELAY_SLOT);
+  __ xori(v0, a0, 1 << Map::kIsUndetectable);
 }


@@ -1673,8 +1672,7 @@

   // Generate code to lookup number in the number string cache.
GenerateLookupNumberStringCache(masm, a1, v0, a2, a3, t0, false, &runtime);
-  __ Addu(sp, sp, Operand(1 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(1);

   __ bind(&runtime);
// Handle number to string in the runtime system if not found in the cache.
@@ -1696,8 +1694,8 @@
     __ JumpIfNotSmi(a2, &not_two_smis);
     __ sra(a1, a1, 1);
     __ sra(a0, a0, 1);
-    __ Subu(v0, a1, a0);
-    __ Ret();
+    __ Ret(USE_DELAY_SLOT);
+    __ subu(v0, a1, a0);
     __ bind(&not_two_smis);
   } else if (FLAG_debug_code) {
     __ Or(a2, a1, a0);
@@ -1916,8 +1914,8 @@
     __ lbu(at, FieldMemOperand(map, Map::kInstanceTypeOffset));
     Label skip;
     __ Branch(&skip, ge, at, Operand(FIRST_NONSTRING_TYPE));
+    __ Ret(USE_DELAY_SLOT);  // the string length is OK as the return value
     __ lw(tos_, FieldMemOperand(tos_, String::kLengthOffset));
-    __ Ret();  // the string length is OK as the return value
     __ bind(&skip);
   }

@@ -2092,8 +2090,8 @@
   __ Branch(slow, eq, t0, Operand(zero_reg));

   // Return '0 - value'.
-  __ Subu(v0, zero_reg, a0);
-  __ Ret();
+  __ Ret(USE_DELAY_SLOT);
+  __ subu(v0, zero_reg, a0);
 }


@@ -2423,8 +2421,8 @@
       // Negating it results in 'lt'.
       __ Branch(&skip, lt, scratch2, Operand(zero_reg));
       ASSERT(Smi::FromInt(0) == 0);
-      __ mov(v0, zero_reg);
-      __ Ret();  // Return smi 0 if the non-zero one was positive.
+      __ Ret(USE_DELAY_SLOT);
+ __ mov(v0, zero_reg); // Return smi 0 if the non-zero one was positive.
       __ bind(&skip);
// We fall through here if we multiplied a negative number with 0, because
       // that would mean we should produce -0.
@@ -2479,23 +2477,23 @@
       }
       break;
     case Token::BIT_OR:
-      __ Or(v0, left, Operand(right));
-      __ Ret();
+      __ Ret(USE_DELAY_SLOT);
+      __ or_(v0, left, right);
       break;
     case Token::BIT_AND:
-      __ And(v0, left, Operand(right));
-      __ Ret();
+      __ Ret(USE_DELAY_SLOT);
+      __ and_(v0, left, right);
       break;
     case Token::BIT_XOR:
-      __ Xor(v0, left, Operand(right));
-      __ Ret();
+      __ Ret(USE_DELAY_SLOT);
+      __ xor_(v0, left, right);
       break;
     case Token::SAR:
       // Remove tags from right operand.
       __ GetLeastBitsFromSmi(scratch1, right, 5);
       __ srav(scratch1, left, scratch1);
       // Smi tag result.
-      __ And(v0, scratch1, Operand(~kSmiTagMask));
+      __ And(v0, scratch1, ~kSmiTagMask);
       __ Ret();
       break;
     case Token::SHR:
@@ -2607,8 +2605,8 @@
         // kValueOffset. On MIPS this workaround is built into sdc1 so
         // there's no point in generating even more instructions.
         __ sdc1(f10, FieldMemOperand(result, HeapNumber::kValueOffset));
+        __ Ret(USE_DELAY_SLOT);
         __ mov(v0, result);
-        __ Ret();
       } else {
         // Call the C function to handle the double operation.
         FloatingPointHelper::CallCCodeForDoubleOperation(masm,
@@ -3482,8 +3480,8 @@
     __ sw(a3, MemOperand(cache_entry, 1 * kPointerSize));
     __ sw(t2, MemOperand(cache_entry, 2 * kPointerSize));

+    __ Ret(USE_DELAY_SLOT);
     __ mov(v0, cache_entry);
-    __ Ret();

     __ bind(&invalid_cache);
     // The cache is invalid. Call runtime which will recreate the
@@ -3662,7 +3660,7 @@
                  ne,
                  double_exponent,
                  double_scratch);
-
+      // double_scratch can be overwritten in the delay slot.
       // Calculates square root of base.  Check for the special case of
       // Math.pow(-Infinity, 0.5) == Infinity (ECMA spec, 15.8.2.13).
       __ Move(double_scratch, -V8_INFINITY);
@@ -3682,7 +3680,7 @@
                  ne,
                  double_exponent,
                  double_scratch);
-
+      // double_scratch can be overwritten in the delay slot.
       // Calculates square root of base.  Check for the special case of
       // Math.pow(-Infinity, -0.5) == 0 (ECMA spec, 15.8.2.13).
       __ Move(double_scratch, -V8_INFINITY);
@@ -3866,9 +3864,10 @@
     __ sw(a1, MemOperand(a0));
   }

-  // Prepare arguments for C routine: a0 = argc, a1 = argv
+  // Prepare arguments for C routine.
+  // a0 = argc
   __ mov(a0, s0);
-  __ mov(a1, s1);
+  // a1 = argv (set in the delay slot after find_ra below).

// We are calling compiled C/C++ code. a0 and a1 hold our two arguments. We
   // also need to reserve the 4 argument slots on the stack.
@@ -3888,29 +3887,27 @@
     // coverage code can interfere with the proper calculation of ra.
     Label find_ra;
     masm->bal(&find_ra);  // bal exposes branch delay slot.
-    masm->nop();  // Branch delay slot nop.
+    masm->mov(a1, s1);
     masm->bind(&find_ra);

     // Adjust the value in ra to point to the correct return location, 2nd
// instruction past the real call into C code (the jalr(t9)), and push it.
     // This is the return address of the exit frame.
-    const int kNumInstructionsToJump = 6;
+    const int kNumInstructionsToJump = 5;
     masm->Addu(ra, ra, kNumInstructionsToJump * kPointerSize);
masm->sw(ra, MemOperand(sp)); // This spot was reserved in EnterExitFrame.
-    masm->Subu(sp, sp, kCArgsSlotsSize);
+    // Stack space reservation moved to the branch delay slot below.
     // Stack is still aligned.

     // Call the C routine.
masm->mov(t9, s2); // Function pointer to t9 to conform to ABI for PIC.
     masm->jalr(t9);
-    masm->nop();    // Branch delay slot nop.
+    // Set up sp in the delay slot.
+    masm->addiu(sp, sp, -kCArgsSlotsSize);
     // Make sure the stored 'ra' points to this position.
     ASSERT_EQ(kNumInstructionsToJump,
               masm->InstructionsGeneratedSince(&find_ra));
   }
-
-  // Restore stack (remove arg slots).
-  __ Addu(sp, sp, kCArgsSlotsSize);

   if (always_allocate) {
     // It's okay to clobber a2 and a3 here. v0 & v1 contain result.
@@ -3925,14 +3922,16 @@
   STATIC_ASSERT(((kFailureTag + 1) & kFailureTagMask) == 0);
   __ addiu(a2, v0, 1);
   __ andi(t0, a2, kFailureTagMask);
-  __ Branch(&failure_returned, eq, t0, Operand(zero_reg));
+  __ Branch(USE_DELAY_SLOT, &failure_returned, eq, t0, Operand(zero_reg));
+  // Restore stack (remove arg slots) in branch delay slot.
+  __ addiu(sp, sp, kCArgsSlotsSize);
+

   // Exit C frame and return.
   // v0:v1: result
   // sp: stack pointer
   // fp: frame pointer
-  __ LeaveExitFrame(save_doubles_, s0);
-  __ Ret();
+  __ LeaveExitFrame(save_doubles_, s0, true);

   // Check if we should retry or throw exception.
   Label retry;
@@ -3943,8 +3942,10 @@

   // Special handling of out of memory exceptions.
   Failure* out_of_memory = Failure::OutOfMemoryException();
-  __ Branch(throw_out_of_memory_exception, eq,
+  __ Branch(USE_DELAY_SLOT, throw_out_of_memory_exception, eq,
             v0, Operand(reinterpret_cast<int32_t>(out_of_memory)));
+  // If we throw the OOM exception, the value of a3 doesn't matter.
+  // Any instruction can be in the delay slot that's not a jump.

   // Retrieve the pending exception and clear the variable.
   __ li(a3, Operand(isolate->factory()->the_hole_value()));
@@ -3968,8 +3969,9 @@

 void CEntryStub::Generate(MacroAssembler* masm) {
// Called from JavaScript; parameters are on stack as if calling JS function
-  // a0: number of arguments including receiver
-  // a1: pointer to builtin function
+  // s0: number of arguments including receiver
+  // s1: size of arguments excluding receiver
+  // s2: pointer to builtin function
   // fp: frame pointer    (restored after C call)
   // sp: stack pointer    (restored as callee's sp after C call)
   // cp: current context  (C callee-saved)
@@ -3979,19 +3981,18 @@
   // this by performing a garbage collection and retrying the
   // builtin once.

+  // NOTE: s0-s2 hold the arguments of this function instead of a0-a2.
+ // The reason for this is that these arguments would need to be saved anyway
+  // so it's faster to set them up directly.
+  // See MacroAssembler::PrepareCEntryArgs and PrepareCEntryFunction.
+
   // Compute the argv pointer in a callee-saved register.
-  __ sll(s1, a0, kPointerSizeLog2);
   __ Addu(s1, sp, s1);
-  __ Subu(s1, s1, Operand(kPointerSize));

   // Enter the exit frame that transitions from JavaScript to C++.
   FrameScope scope(masm, StackFrame::MANUAL);
   __ EnterExitFrame(save_doubles_);

-  // Set up argc and the builtin function in callee-saved registers.
-  __ mov(s0, a0);
-  __ mov(s2, a1);
-
   // s0: number of arguments (C callee-saved)
   // s1: pointer to first argument (C callee-saved)
   // s2: pointer to builtin function (C callee-saved)
@@ -4693,8 +4694,7 @@
   __ Branch(&arguments_loop, lt, t5, Operand(a2));

   // Return and remove the on-stack parameters.
-  __ Addu(sp, sp, Operand(3 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(3);

   // Do the runtime call to allocate the arguments object.
   // a2 = argument count (tagged)
@@ -4799,8 +4799,7 @@

   // Return and remove the on-stack parameters.
   __ bind(&done);
-  __ Addu(sp, sp, Operand(3 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(3);

   // Do the runtime call to allocate the arguments object.
   __ bind(&runtime);
@@ -5149,8 +5148,7 @@
   __ bind(&failure);
   // For failure and exception return null.
   __ li(v0, Operand(isolate->factory()->null_value()));
-  __ Addu(sp, sp, Operand(4 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(4);

   // Process the result from the native regexp code.
   __ bind(&success);
@@ -5211,14 +5209,13 @@
   __ sll(a3, a3, kSmiTagSize);  // Convert to Smi.
   __ sw(a3, MemOperand(a0, 0));
   __ Branch(&next_capture, USE_DELAY_SLOT);
-  __ addiu(a0, a0, kPointerSize);   // In branch delay slot.
+  __ addiu(a0, a0, kPointerSize);  // In branch delay slot.

   __ bind(&done);

   // Return last match info.
   __ lw(v0, MemOperand(sp, kLastMatchInfoOffset));
-  __ Addu(sp, sp, Operand(4 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(4);

   // External string.  Short external strings have already been ruled out.
   // a0: scratch
@@ -5330,8 +5327,7 @@
   __ addiu(a3, a3, kPointerSize);  // In branch delay slot.

   __ bind(&done);
-  __ Addu(sp, sp, Operand(3 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(3);

   __ bind(&slowcase);
   __ TailCallRuntime(Runtime::kRegExpConstructResult, 3, 1);
@@ -6136,7 +6132,7 @@
   STATIC_ASSERT(kIsIndirectStringMask != 0);
   __ And(t0, a1, Operand(kIsIndirectStringMask));
__ Branch(USE_DELAY_SLOT, &seq_or_external_string, eq, t0, Operand(zero_reg));
-
+ // t0 is used as a scratch register and can be overwritten in either case.
   __ And(t0, a1, Operand(kSlicedNotConsMask));
   __ Branch(&sliced_string, ne, t0, Operand(zero_reg));
   // Cons string.  Check whether it is flat, then fetch first part.
@@ -6409,8 +6405,7 @@
   STATIC_ASSERT(kSmiTag == 0);
   __ li(v0, Operand(Smi::FromInt(EQUAL)));
   __ IncrementCounter(counters->string_compare_native(), 1, a1, a2);
-  __ Addu(sp, sp, Operand(2 * kPointerSize));
-  __ Ret();
+  __ DropAndRet(2);

   __ bind(&not_same);

@@ -6815,16 +6810,16 @@
     __ BranchF(&fpu_lt, NULL, lt, f0, f2);

     // Otherwise it's greater, so just fall thru, and return.
-    __ Ret(USE_DELAY_SLOT);
-    __ li(v0, Operand(GREATER));  // In delay slot.
+    __ li(v0, Operand(GREATER));
+    __ Ret();

     __ bind(&fpu_eq);
-    __ Ret(USE_DELAY_SLOT);
-    __ li(v0, Operand(EQUAL));  // In delay slot.
+    __ li(v0, Operand(EQUAL));
+    __ Ret();

     __ bind(&fpu_lt);
-    __ Ret(USE_DELAY_SLOT);
-    __ li(v0, Operand(LESS));  // In delay slot.
+    __ li(v0, Operand(LESS));
+    __ Ret();
   }

   __ bind(&unordered);
@@ -6924,9 +6919,9 @@
   Label left_ne_right;
   STATIC_ASSERT(EQUAL == 0);
   STATIC_ASSERT(kSmiTag == 0);
-  __ Branch(&left_ne_right, ne, left, Operand(right), USE_DELAY_SLOT);
+  __ Branch(&left_ne_right, ne, left, Operand(right));
+  __ Ret(USE_DELAY_SLOT);
   __ mov(v0, zero_reg);  // In the delay slot.
-  __ Ret();
   __ bind(&left_ne_right);

   // Handle not identical strings.
@@ -6939,12 +6934,12 @@
     __ And(tmp3, tmp1, Operand(tmp2));
     __ And(tmp5, tmp3, Operand(kIsSymbolMask));
     Label is_symbol;
-    __ Branch(&is_symbol, eq, tmp5, Operand(zero_reg), USE_DELAY_SLOT);
-    __ mov(v0, a0);  // In the delay slot.
+    __ Branch(&is_symbol, eq, tmp5, Operand(zero_reg));
     // Make sure a0 is non-zero. At this point input operands are
     // guaranteed to be non-zero.
     ASSERT(right.is(a0));
-    __ Ret();
+    __ Ret(USE_DELAY_SLOT);
+    __ mov(v0, a0);  // In the delay slot.
     __ bind(&is_symbol);
   }

@@ -6988,8 +6983,8 @@
   __ Branch(&miss, ne, a2, Operand(JS_OBJECT_TYPE));

   ASSERT(GetCondition() == eq);
-  __ Subu(v0, a0, Operand(a1));
-  __ Ret();
+  __ Ret(USE_DELAY_SLOT);
+  __ subu(v0, a0, a1);

   __ bind(&miss);
   GenerateMiss(masm);
@@ -7022,8 +7017,9 @@
     __ push(ra);
     __ Push(a1, a0);
     __ li(t0, Operand(Smi::FromInt(op_)));
-    __ push(t0);
-    __ CallExternalReference(miss, 3);
+    __ addiu(sp, sp, -kPointerSize);
+    __ CallExternalReference(miss, 3, USE_DELAY_SLOT);
+    __ sw(t0, MemOperand(sp));  // In the delay slot.
     // Compute the entry point of the rewritten stub.
     __ Addu(a2, v0, Operand(Code::kHeaderSize - kHeapObjectTag));
     // Restore registers.
@@ -7333,17 +7329,17 @@
   // treated as a lookup success. For positive lookup probing failure
   // should be treated as lookup failure.
   if (mode_ == POSITIVE_LOOKUP) {
+    __ Ret(USE_DELAY_SLOT);
     __ mov(result, zero_reg);
-    __ Ret();
   }

   __ bind(&in_dictionary);
+  __ Ret(USE_DELAY_SLOT);
   __ li(result, 1);
-  __ Ret();

   __ bind(&not_in_dictionary);
+  __ Ret(USE_DELAY_SLOT);
   __ mov(result, zero_reg);
-  __ Ret();
 }


=======================================
--- /trunk/src/mips/debug-mips.cc       Wed Feb  1 02:48:36 2012
+++ /trunk/src/mips/debug-mips.cc       Wed Mar 21 02:52:17 2012
@@ -152,8 +152,8 @@
 #ifdef DEBUG
__ RecordComment("// Calling from debug break to runtime - come in - over");
 #endif
-    __ mov(a0, zero_reg);  // No arguments.
-    __ li(a1, Operand(ExternalReference::debug_break(masm->isolate())));
+    __ PrepareCEntryArgs(0);  // No arguments.
+ __ PrepareCEntryFunction(ExternalReference::debug_break(masm->isolate()));

     CEntryStub ceb(1);
     __ CallStub(&ceb);
=======================================
--- /trunk/src/mips/ic-mips.cc  Wed Mar 14 04:16:03 2012
+++ /trunk/src/mips/ic-mips.cc  Wed Mar 21 02:52:17 2012
@@ -512,8 +512,8 @@
     __ Push(a3, a2);

     // Call the entry.
-    __ li(a0, Operand(2));
-    __ li(a1, Operand(ExternalReference(IC_Utility(id), isolate)));
+    __ PrepareCEntryArgs(2);
+    __ PrepareCEntryFunction(ExternalReference(IC_Utility(id), isolate));

     CEntryStub stub(1);
     __ CallStub(&stub);
@@ -844,8 +844,8 @@
   Label slow, notin;
   MemOperand mapped_location =
GenerateMappedArgumentsLookup(masm, a1, a0, a2, a3, t0, &notin, &slow);
+  __ Ret(USE_DELAY_SLOT);
   __ lw(v0, mapped_location);
-  __ Ret();
   __ bind(&notin);
   // The unmapped lookup expects that the parameter map is in a2.
   MemOperand unmapped_location =
@@ -853,8 +853,8 @@
   __ lw(a2, unmapped_location);
   __ LoadRoot(a3, Heap::kTheHoleValueRootIndex);
   __ Branch(&slow, eq, a2, Operand(a3));
+  __ Ret(USE_DELAY_SLOT);
   __ mov(v0, a2);
-  __ Ret();
   __ bind(&slow);
   GenerateMiss(masm, false);
 }
=======================================
--- /trunk/src/mips/lithium-codegen-mips.cc     Tue Mar 20 06:01:16 2012
+++ /trunk/src/mips/lithium-codegen-mips.cc     Wed Mar 21 02:52:17 2012
@@ -634,13 +634,9 @@
     __ bind(&skip);
   }

-  if (cc == al) {
-    __ Jump(entry, RelocInfo::RUNTIME_ENTRY);
-  } else {
-    // TODO(plind): The Arm port is a little different here, due to their
-    // DeOpt jump table, which is not used for Mips yet.
-    __ Jump(entry, RelocInfo::RUNTIME_ENTRY, cc, src1, src2);
-  }
+  // TODO(plind): The Arm port is a little different here, due to their
+  // DeOpt jump table, which is not used for Mips yet.
+  __ Jump(entry, RelocInfo::RUNTIME_ENTRY, cc, src1, src2);
 }


=======================================
--- /trunk/src/mips/macro-assembler-mips.cc     Wed Mar 14 04:16:03 2012
+++ /trunk/src/mips/macro-assembler-mips.cc     Wed Mar 21 02:52:17 2012
@@ -2438,8 +2438,15 @@
                           Register rs,
                           const Operand& rt,
                           BranchDelaySlot bd) {
+  Label skip;
+  if (cond != cc_always) {
+    Branch(USE_DELAY_SLOT, &skip, NegateCondition(cond), rs, rt);
+  }
+  // The first instruction of 'li' may be placed in the delay slot.
+  // This is not an issue, t9 is expected to be clobbered anyway.
   li(t9, Operand(target, rmode));
-  Jump(t9, cond, rs, rt, bd);
+  Jump(t9, al, zero_reg, Operand(zero_reg), bd);
+  bind(&skip);
 }


@@ -2569,7 +2576,7 @@
     rmode = RelocInfo::CODE_TARGET_WITH_ID;
   }
Call(reinterpret_cast<Address>(code.location()), rmode, cond, rs, rt, bd);
-  ASSERT_EQ(CallSize(code, rmode, ast_id, cond, rs, rt),
+  ASSERT_EQ(CallSize(code, rmode, ast_id, cond, rs, rt, bd),
             SizeOfCodeGeneratedSince(&start));
 }

@@ -2639,14 +2646,16 @@
     nop();
 }

+void MacroAssembler::DropAndRet(int drop) {
+  Ret(USE_DELAY_SLOT);
+  addiu(sp, sp, drop * kPointerSize);
+}

 void MacroAssembler::DropAndRet(int drop,
                                 Condition cond,
                                 Register r1,
                                 const Operand& r2) {
-  // This is a workaround to make sure only one branch instruction is
-  // generated. It relies on Drop and Ret not creating branches if
-  // cond == cc_always.
+  // Both Drop and Ret need to be conditional.
   Label skip;
   if (cond != cc_always) {
     Branch(&skip, NegateCondition(cond), r1, r2);
@@ -2713,8 +2722,8 @@
 #ifdef ENABLE_DEBUGGER_SUPPORT

 void MacroAssembler::DebugBreak() {
-  mov(a0, zero_reg);
-  li(a1, Operand(ExternalReference(Runtime::kDebugBreak, isolate())));
+  PrepareCEntryArgs(0);
+ PrepareCEntryFunction(ExternalReference(Runtime::kDebugBreak, isolate()));
   CEntryStub ces(1);
   ASSERT(AllowThisStubCall(&ces));
   Call(ces.GetCode(), RelocInfo::DEBUG_BREAK);
@@ -3876,10 +3885,13 @@
// -----------------------------------------------------------------------------
 // Runtime calls.

-void MacroAssembler::CallStub(CodeStub* stub, Condition cond,
-                              Register r1, const Operand& r2) {
+void MacroAssembler::CallStub(CodeStub* stub,
+                              Condition cond,
+                              Register r1,
+                              const Operand& r2,
+                              BranchDelaySlot bd) {
ASSERT(AllowThisStubCall(stub)); // Stub calls are not allowed in some stubs.
-  Call(stub->GetCode(), RelocInfo::CODE_TARGET, kNoASTId, cond, r1, r2);
+ Call(stub->GetCode(), RelocInfo::CODE_TARGET, kNoASTId, cond, r1, r2, bd);
 }


@@ -3962,8 +3974,7 @@
   lw(t1, MemOperand(at));
   Branch(&promote_scheduled_exception, ne, t0, Operand(t1));
   li(s0, Operand(stack_space));
-  LeaveExitFrame(false, s0);
-  Ret();
+  LeaveExitFrame(false, s0, true);

   bind(&promote_scheduled_exception);
   TailCallExternalReference(
@@ -4161,8 +4172,8 @@
   // arguments passed in because it is constant. At some point we
   // should remove this need and make the runtime routine entry code
   // smarter.
-  li(a0, num_arguments);
-  li(a1, Operand(ExternalReference(f, isolate())));
+  PrepareCEntryArgs(num_arguments);
+  PrepareCEntryFunction(ExternalReference(f, isolate()));
   CEntryStub stub(1);
   CallStub(&stub);
 }
@@ -4170,8 +4181,8 @@

 void MacroAssembler::CallRuntimeSaveDoubles(Runtime::FunctionId id) {
   const Runtime::Function* function = Runtime::FunctionForId(id);
-  li(a0, Operand(function->nargs));
-  li(a1, Operand(ExternalReference(function, isolate())));
+  PrepareCEntryArgs(function->nargs);
+  PrepareCEntryFunction(ExternalReference(function, isolate()));
   CEntryStub stub(1, kSaveFPRegs);
   CallStub(&stub);
 }
@@ -4183,12 +4194,13 @@


 void MacroAssembler::CallExternalReference(const ExternalReference& ext,
-                                           int num_arguments) {
-  li(a0, Operand(num_arguments));
-  li(a1, Operand(ext));
+                                           int num_arguments,
+                                           BranchDelaySlot bd) {
+  PrepareCEntryArgs(num_arguments);
+  PrepareCEntryFunction(ext);

   CEntryStub stub(1);
-  CallStub(&stub);
+  CallStub(&stub, al, zero_reg, Operand(zero_reg), bd);
 }


@@ -4199,7 +4211,7 @@
   // arguments passed in because it is constant. At some point we
   // should remove this need and make the runtime routine entry code
   // smarter.
-  li(a0, Operand(num_arguments));
+  PrepareCEntryArgs(num_arguments);
   JumpToExternalReference(ext);
 }

@@ -4213,10 +4225,16 @@
 }


-void MacroAssembler::JumpToExternalReference(const ExternalReference& builtin) {
-  li(a1, Operand(builtin));
+void MacroAssembler::JumpToExternalReference(const ExternalReference& builtin,
+                                             BranchDelaySlot bd) {
+  PrepareCEntryFunction(builtin);
   CEntryStub stub(1);
-  Jump(stub.GetCode(), RelocInfo::CODE_TARGET);
+  Jump(stub.GetCode(),
+       RelocInfo::CODE_TARGET,
+       al,
+       zero_reg,
+       Operand(zero_reg),
+       bd);
 }


@@ -4563,7 +4581,8 @@


 void MacroAssembler::LeaveExitFrame(bool save_doubles,
-                                    Register argument_count) {
+                                    Register argument_count,
+                                    bool do_return) {
   // Optionally restore all double registers.
   if (save_doubles) {
     // Remember: we only need to restore every 2nd double FPU value.
@@ -4589,11 +4608,17 @@
   mov(sp, fp);  // Respect ABI stack constraint.
   lw(fp, MemOperand(sp, ExitFrameConstants::kCallerFPOffset));
   lw(ra, MemOperand(sp, ExitFrameConstants::kCallerPCOffset));
-  addiu(sp, sp, 8);
+
   if (argument_count.is_valid()) {
     sll(t8, argument_count, kPointerSizeLog2);
     addu(sp, sp, t8);
   }
+
+  if (do_return) {
+    Ret(USE_DELAY_SLOT);
+ // If returning, the instruction in the delay slot will be the addiu below.
+  }
+  addiu(sp, sp, 8);
 }


=======================================
--- /trunk/src/mips/macro-assembler-mips.h      Mon Mar 19 04:01:52 2012
+++ /trunk/src/mips/macro-assembler-mips.h      Wed Mar 21 02:52:17 2012
@@ -193,10 +193,14 @@
             Register reg = no_reg,
             const Operand& op = Operand(no_reg));

-  void DropAndRet(int drop = 0,
-                  Condition cond = cc_always,
-                  Register reg = no_reg,
-                  const Operand& op = Operand(no_reg));
+  // Trivial case of DropAndRet that utilizes the delay slot and only emits
+  // 2 instructions.
+  void DropAndRet(int drop);
+
+  void DropAndRet(int drop,
+                  Condition cond,
+                  Register reg,
+                  const Operand& op);

// Swap two registers. If the scratch register is omitted then a slightly
   // less efficient form using xor instead of mov is emitted.
@@ -773,7 +777,9 @@
                       int stack_space = 0);

   // Leave the current exit frame.
-  void LeaveExitFrame(bool save_doubles, Register arg_count);
+  void LeaveExitFrame(bool save_doubles,
+                      Register arg_count,
+                      bool do_return = false);

   // Get the actual activation frame alignment for target environment.
   static int ActivationFrameAlignment();
@@ -1083,10 +1089,23 @@

// -------------------------------------------------------------------------
   // Runtime calls.
+
+  // See comments at the beginning of CEntryStub::Generate.
+  inline void PrepareCEntryArgs(int num_args) {
+    li(s0, num_args);
+    li(s1, (num_args - 1) * kPointerSize);
+  }
+
+  inline void PrepareCEntryFunction(const ExternalReference& ref) {
+    li(s2, Operand(ref));
+  }

   // Call a code stub.
-  void CallStub(CodeStub* stub, Condition cond = cc_always,
- Register r1 = zero_reg, const Operand& r2 = Operand(zero_reg));
+  void CallStub(CodeStub* stub,
+                Condition cond = cc_always,
+                Register r1 = zero_reg,
+                const Operand& r2 = Operand(zero_reg),
+                BranchDelaySlot bd = PROTECT);

   // Tail call a code stub (jump).
   void TailCallStub(CodeStub* stub);
@@ -1102,7 +1121,8 @@

   // Convenience function: call an external reference.
   void CallExternalReference(const ExternalReference& ext,
-                             int num_arguments);
+                             int num_arguments,
+                             BranchDelaySlot bd = PROTECT);

   // Tail call of a runtime routine (jump).
// Like JumpToExternalReference, but also takes care of passing the number
@@ -1168,7 +1188,8 @@
void CallApiFunctionAndReturn(ExternalReference function, int stack_space);

   // Jump to the builtin routine.
-  void JumpToExternalReference(const ExternalReference& builtin);
+  void JumpToExternalReference(const ExternalReference& builtin,
+                               BranchDelaySlot bd = PROTECT);

   // Invoke specified builtin JavaScript function. Adds an entry to
   // the unresolved list if the name does not resolve.
=======================================
--- /trunk/src/mips/simulator-mips.h    Thu Nov 10 03:38:15 2011
+++ /trunk/src/mips/simulator-mips.h    Wed Mar 21 02:52:17 2012
@@ -309,6 +309,14 @@
   void InstructionDecode(Instruction* instr);
   // Execute one instruction placed in a branch delay slot.
   void BranchDelayInstructionDecode(Instruction* instr) {
+    if (instr->InstructionBits() == nopInstr) {
+      // Short-cut generic nop instructions. They are always valid and they
+      // never change the simulator state.
+      set_register(pc, reinterpret_cast<int32_t>(instr) +
+                       Instruction::kInstrSize);
+      return;
+    }
+
     if (instr->IsForbiddenInBranchDelay()) {
       V8_Fatal(__FILE__, __LINE__,
                "Eror:Unexpected %i opcode in a branch delay slot.",
=======================================
--- /trunk/src/mips/stub-cache-mips.cc  Wed Mar 14 04:16:03 2012
+++ /trunk/src/mips/stub-cache-mips.cc  Wed Mar 21 02:52:17 2012
@@ -577,8 +577,8 @@
   ExternalReference ref =
       ExternalReference(IC_Utility(IC::kLoadPropertyWithInterceptorOnly),
           masm->isolate());
-  __ li(a0, Operand(5));
-  __ li(a1, Operand(ref));
+  __ PrepareCEntryArgs(5);
+  __ PrepareCEntryFunction(ref);

   CEntryStub stub(1);
   __ CallStub(&stub);
@@ -4107,7 +4107,8 @@
   // have been verified by the caller to not be a smi.

   // Check that the key is a smi.
-  __ JumpIfNotSmi(a0, &miss_force_generic);
+  __ JumpIfNotSmi(a0, &miss_force_generic, at, USE_DELAY_SLOT);
+  // The delay slot can be safely used here, a1 is an object pointer.

   // Get the elements array.
   __ lw(a2, FieldMemOperand(a1, JSObject::kElementsOffset));
@@ -4115,7 +4116,7 @@

   // Check that the key is within bounds.
   __ lw(a3, FieldMemOperand(a2, FixedArray::kLengthOffset));
-  __ Branch(&miss_force_generic, hs, a0, Operand(a3));
+  __ Branch(USE_DELAY_SLOT, &miss_force_generic, hs, a0, Operand(a3));

   // Load the result and make sure it's not the hole.
   __ Addu(a3, a2, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
@@ -4125,8 +4126,8 @@
   __ lw(t0, MemOperand(t0));
   __ LoadRoot(t1, Heap::kTheHoleValueRootIndex);
   __ Branch(&miss_force_generic, eq, t0, Operand(t1));
+  __ Ret(USE_DELAY_SLOT);
   __ mov(v0, t0);
-  __ Ret();

   __ bind(&miss_force_generic);
   Handle<Code> stub =
=======================================
--- /trunk/src/objects.cc       Mon Mar 19 04:01:52 2012
+++ /trunk/src/objects.cc       Wed Mar 21 02:52:17 2012
@@ -7380,7 +7380,6 @@
   ASSERT(is_compiled() && !IsOptimized());
   ASSERT(shared()->allows_lazy_compilation() ||
          code()->optimizable());
-  ASSERT(!shared()->optimization_disabled());
   Builtins* builtins = GetIsolate()->builtins();
   ReplaceCode(builtins->builtin(Builtins::kLazyRecompile));
 }
=======================================
--- /trunk/src/runtime-profiler.cc      Tue Mar 13 01:09:54 2012
+++ /trunk/src/runtime-profiler.cc      Wed Mar 21 02:52:17 2012
@@ -268,6 +268,7 @@

     // Do not record non-optimizable functions.
     if (!function->IsOptimizable()) continue;
+    if (function->shared()->optimization_disabled()) continue;

     // Only record top-level code on top of the execution stack and
     // avoid optimizing excessively large scripts since top-level code
=======================================
--- /trunk/src/version.cc       Tue Mar 20 06:01:16 2012
+++ /trunk/src/version.cc       Wed Mar 21 02:52:17 2012
@@ -34,7 +34,7 @@
 // cannot be changed without changing the SCons build script.
 #define MAJOR_VERSION     3
 #define MINOR_VERSION     9
-#define BUILD_NUMBER      22
+#define BUILD_NUMBER      23
 #define PATCH_LEVEL       0
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)
=======================================
--- /trunk/test/cctest/test-heap-profiler.cc    Fri Mar  9 02:52:05 2012
+++ /trunk/test/cctest/test-heap-profiler.cc    Wed Mar 21 02:52:17 2012
@@ -352,6 +352,59 @@
 #define CHECK_NE_UINT64_T(a, b) \
   CHECK((a) != (b))  // NOLINT

+TEST(HeapEntryIdsAndArrayShift) {
+  v8::HandleScope scope;
+  LocalContext env;
+
+  CompileRun(
+      "function AnObject() {\n"
+      "    this.first = 'first';\n"
+      "    this.second = 'second';\n"
+      "}\n"
+      "var a = new Array();\n"
+      "for (var i = 0; i < 10; ++i)\n"
+      "  a.push(new AnObject());\n");
+  const v8::HeapSnapshot* snapshot1 =
+      v8::HeapProfiler::TakeSnapshot(v8_str("s1"));
+
+  CompileRun(
+      "for (var i = 0; i < 1; ++i)\n"
+      "  a.shift();\n");
+
+  HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
+
+  const v8::HeapSnapshot* snapshot2 =
+      v8::HeapProfiler::TakeSnapshot(v8_str("s2"));
+
+  const v8::HeapGraphNode* global1 = GetGlobalObject(snapshot1);
+  const v8::HeapGraphNode* global2 = GetGlobalObject(snapshot2);
+  CHECK_NE_UINT64_T(0, global1->GetId());
+  CHECK_EQ_UINT64_T(global1->GetId(), global2->GetId());
+
+  const v8::HeapGraphNode* a1 =
+      GetProperty(global1, v8::HeapGraphEdge::kProperty, "a");
+  CHECK_NE(NULL, a1);
+  const v8::HeapGraphNode* e1 =
+      GetProperty(a1, v8::HeapGraphEdge::kHidden, "1");
+  CHECK_NE(NULL, e1);
+  const v8::HeapGraphNode* k1 =
+      GetProperty(e1, v8::HeapGraphEdge::kInternal, "elements");
+  CHECK_NE(NULL, k1);
+  const v8::HeapGraphNode* a2 =
+      GetProperty(global2, v8::HeapGraphEdge::kProperty, "a");
+  CHECK_NE(NULL, a2);
+  const v8::HeapGraphNode* e2 =
+      GetProperty(a2, v8::HeapGraphEdge::kHidden, "1");
+  CHECK_NE(NULL, e2);
+  const v8::HeapGraphNode* k2 =
+      GetProperty(e2, v8::HeapGraphEdge::kInternal, "elements");
+  CHECK_NE(NULL, k2);
+
+  CHECK_EQ_UINT64_T(a1->GetId(), a2->GetId());
+  CHECK_EQ_UINT64_T(e1->GetId(), e2->GetId());
+  CHECK_EQ_UINT64_T(k1->GetId(), k2->GetId());
+}
+
 TEST(HeapEntryIdsAndGC) {
   v8::HandleScope scope;
   LocalContext env;
=======================================
--- /trunk/test/cctest/test-log-stack-tracer.cc Tue Mar 20 06:01:16 2012
+++ /trunk/test/cctest/test-log-stack-tracer.cc Wed Mar 21 02:52:17 2012
@@ -277,9 +277,7 @@
 TEST(CFromJSStackTrace) {
// BUG(1303) Inlining of JSFuncDoTrace() in JSTrace below breaks this test.
   i::FLAG_use_inlining = false;
- // This test does not work with --always-opt because we don't replace the code
-  // in the JSFunction at deoptimization in that case.
-  i::FLAG_always_opt = false;
+
   TickSample sample;
   InitTraceEnv(&sample);

=======================================
--- /trunk/test/mjsunit/compiler/inline-arguments.js Wed Mar 14 04:16:03 2012 +++ /trunk/test/mjsunit/compiler/inline-arguments.js Wed Mar 21 02:52:17 2012
@@ -80,3 +80,36 @@
 F4(1);
 %OptimizeFunctionOnNextCall(F4);
 F4(1);
+
+
+// Test correct adapation of arguments.
+// Strict mode prevents arguments object from shadowing parameters.
+(function () {
+  "use strict";
+
+  function G2() {
+    assertArrayEquals([1,2], arguments);
+  }
+
+  function G4() {
+    assertArrayEquals([1,2,3,4], arguments);
+  }
+
+  function adapt2to4(a, b, c, d) {
+    G2.apply(this, arguments);
+  }
+
+  function adapt4to2(a, b) {
+    G4.apply(this, arguments);
+  }
+
+  function test_adaptation() {
+    adapt2to4(1, 2);
+    adapt4to2(1, 2, 3, 4);
+  }
+
+  test_adaptation();
+  test_adaptation();
+  %OptimizeFunctionOnNextCall(test_adaptation);
+  test_adaptation();
+})();

--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev

Reply via email to