Merge (7265, 7271] from bleeding_edge to experimental/gc branch....

src/lithium-allocator.cc

Index: src/lithium-allocator.cc
===================================================================
--- src/lithium-allocator.cc	(revision 7563)
+++ src/lithium-allocator.cc	(working copy)
@@ -25,6 +25,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+#include "v8.h"
 #include "lithium-allocator-inl.h"
 
 #include "hydrogen.h"
@@ -44,13 +45,18 @@
 namespace internal {
 
 
-#define DEFINE_OPERAND_CACHE(name, type)            \
-  name name::cache[name::kNumCachedOperands];       \
-  void name::SetupCache() {                         \
-    for (int i = 0; i < kNumCachedOperands; i++) {  \
-      cache[i].ConvertTo(type, i);                  \
-    }                                               \
-  }
+#define DEFINE_OPERAND_CACHE(name, type)                      \
+  name name::cache[name::kNumCachedOperands];                 \
+  void name::SetupCache() {                                   \
+    for (int i = 0; i < kNumCachedOperands; i++) {            \
+      cache[i].ConvertTo(type, i);                            \
+    }                                                         \
+  }                                                           \
+  static bool name##_initialize() {                           \
+    name::SetupCache();                                       \
+    return true;                                              \
+  }                                                           \
+  static bool name##_cache_initialized = name##_initialize();
 
 DEFINE_OPERAND_CACHE(LConstantOperand, CONSTANT_OPERAND)
 DEFINE_OPERAND_CACHE(LStackSlot,       STACK_SLOT)
@@ -1021,6 +1027,22 @@
       chunk_->AddGapMove(cur_block->last_instruction_index() - 1,
                          operand,
                          phi_operand);
+
+      // We are going to insert a move before the branch instruction.
+      // Some branch instructions (e.g. loops' back edges)
+      // can potentially cause a GC so they have a pointer map.
+      // By insterting a move we essentially create a copy of a
+      // value which is invisible to PopulatePointerMaps(), because we store
+      // it into a location different from the operand of a live range
+      // covering a branch instruction.
+      // Thus we need to manually record a pointer.
+      if (phi->representation().IsTagged()) {
+        LInstruction* branch =
+            InstructionAt(cur_block->last_instruction_index());
+        if (branch->HasPointerMap()) {
+          branch->pointer_map()->RecordPointer(phi_operand);
+        }
+      }
     }
 
     LiveRange* live_range = LiveRangeFor(phi->id());
@@ -1550,15 +1572,6 @@
 }
 
 
-void LAllocator::Setup() {
-  LConstantOperand::SetupCache();
-  LStackSlot::SetupCache();
-  LDoubleStackSlot::SetupCache();
-  LRegister::SetupCache();
-  LDoubleRegister::SetupCache();
-}
-
-
 const char* LAllocator::RegisterName(int allocation_index) {
   ASSERT(mode_ != NONE);
   if (mode_ == GENERAL_REGISTERS) {