Generate a custom OSR entrypoint for OSR compiles on all platforms, and transition to optimized cod…

src/arm/lithium-codegen-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 13 matching lines @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (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 "arm/lithium-codegen-arm.h"
 #include "arm/lithium-gap-resolver-arm.h"
 #include "code-stubs.h"
 #include "stub-cache.h"
+#include "hydrogen-osr.h"
 
 namespace v8 {
 namespace internal {
 
 
 class SafepointGenerator : public CallWrapper {
  public:
   SafepointGenerator(LCodeGen* codegen,
                      LPointerMap* pointers,
                      Safepoint::DeoptMode mode)
@@ skipping 202 matching lines @@
   }
 
   // Trace the call.
   if (FLAG_trace && info()->IsOptimizing()) {
     __ CallRuntime(Runtime::kTraceEnter, 0);
   }
   return !is_aborted();
 }
 
 
+void LCodeGen::GenerateOsrPrologue() {
+  // Generate the OSR entry prologue at the first unknown OSR value, or if there
+  // are none, at the OSR entrypoint instruction.
+  if (osr_pc_offset_ >= 0) return;
+
+  osr_pc_offset_ = masm()->pc_offset();
+
+  // Adjust the frame size, subsuming the unoptimized frame into the
+  // optimized frame.
+  int slots = GetStackSlotCount() - graph()->osr()->UnoptimizedFrameSlots();
+  ASSERT(slots >= 0);
+  __ sub(sp, sp, Operand(slots * kPointerSize));
+}
+
+
 bool LCodeGen::GenerateBody() {
   ASSERT(is_generating());
   bool emit_instructions = true;
   for (current_instruction_ = 0;
        !is_aborted() && current_instruction_ < instructions_->length();
        current_instruction_++) {
     LInstruction* instr = instructions_->at(current_instruction_);
 
     // Don't emit code for basic blocks with a replacement.
     if (instr->IsLabel()) {
@@ skipping 791 matching lines @@
       CallCode(stub.GetCode(isolate()), RelocInfo::CODE_TARGET, instr);
       break;
     }
     default:
       UNREACHABLE();
   }
 }
 
 
 void LCodeGen::DoUnknownOSRValue(LUnknownOSRValue* instr) {
-  // Record the address of the first unknown OSR value as the place to enter.
-  if (osr_pc_offset_ == -1) osr_pc_offset_ = masm()->pc_offset();
+  GenerateOsrPrologue();
 }
 
 
 void LCodeGen::DoModI(LModI* instr) {
   HMod* hmod = instr->hydrogen();
   HValue* left = hmod->left();
   HValue* right = hmod->right();
   if (hmod->HasPowerOf2Divisor()) {
     // TODO(svenpanne) We should really do the strength reduction on the
     // Hydrogen level.
@@ skipping 4649 matching lines @@
   // This is a pseudo-instruction that ensures that the environment here is
   // properly registered for deoptimization and records the assembler's PC
   // offset.
   LEnvironment* environment = instr->environment();
 
   // If the environment were already registered, we would have no way of
   // backpatching it with the spill slot operands.
   ASSERT(!environment->HasBeenRegistered());
   RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
 
-  // Normally we record the first unknown OSR value as the entrypoint to the OSR
-  // code, but if there were none, record the entrypoint here.
-  if (osr_pc_offset_ == -1) osr_pc_offset_ = masm()->pc_offset();
+  GenerateOsrPrologue();
 }
 
 
 void LCodeGen::DoForInPrepareMap(LForInPrepareMap* instr) {
   __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   __ cmp(r0, ip);
   DeoptimizeIf(eq, instr->environment());
 
   Register null_value = r5;
   __ LoadRoot(null_value, Heap::kNullValueRootIndex);
@@ skipping 80 matching lines @@
   __ sub(scratch, result, Operand::PointerOffsetFromSmiKey(index));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal