Do stack checks while pushing locals

src/arm/full-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 93 matching lines @@
 
  private:
   MacroAssembler* masm_;
   Label patch_site_;
 #ifdef DEBUG
   bool info_emitted_;
 #endif
 };
 
 
+static void EmitStackCheck(MacroAssembler* masm_,
+                           Register stack_limit_scratch,
+                           int pointers = 0,
+                           Register scratch = sp) {
+    Isolate* isolate = masm_->isolate();
+  Label ok;
+  ASSERT(scratch.is(sp) == (pointers == 0));
+  if (pointers != 0) {
+    __ sub(scratch, sp, Operand(pointers * kPointerSize));
+  }
+  __ LoadRoot(stack_limit_scratch, Heap::kStackLimitRootIndex);
+  __ cmp(scratch, Operand(stack_limit_scratch));
+  __ b(hs, &ok);
+  PredictableCodeSizeScope predictable(masm_, 2 * Assembler::kInstrSize);
+  __ Call(isolate->builtins()->StackCheck(), RelocInfo::CODE_TARGET);
+  __ bind(&ok);
+}
+
+
 // Generate code for a JS function.  On entry to the function the receiver
 // and arguments have been pushed on the stack left to right.  The actual
 // argument count matches the formal parameter count expected by the
 // function.
 //
 // The live registers are:
 //   o r1: the JS function object being called (i.e., ourselves)
 //   o cp: our context
 //   o pp: our caller's constant pool pointer (if FLAG_enable_ool_constant_pool)
 //   o fp: our caller's frame pointer
@@ skipping 48 matching lines @@
 
   info->set_prologue_offset(masm_->pc_offset());
   __ Prologue(BUILD_FUNCTION_FRAME);
   info->AddNoFrameRange(0, masm_->pc_offset());
 
   { Comment cmnt(masm_, "[ Allocate locals");
     int locals_count = info->scope()->num_stack_slots();
     // Generators allocate locals, if any, in context slots.
     ASSERT(!info->function()->is_generator() || locals_count == 0);
     if (locals_count > 0) {
-      // Emit a loop to initialize stack cells for locals when optimizing for
-      // size. Otherwise, unroll the loop for maximum performance.
+      if (locals_count >= 128) {
+        EmitStackCheck(masm_, r2, locals_count, r9);
+      }
       __ LoadRoot(r9, Heap::kUndefinedValueRootIndex);
-      if (FLAG_optimize_for_size && locals_count > 4) {
-        Label loop;
-        __ mov(r2, Operand(locals_count));
-        __ bind(&loop);
-        __ sub(r2, r2, Operand(1), SetCC);
-        __ push(r9);
-        __ b(&loop, ne);
-      } else {
-        for (int i = 0; i < locals_count; i++) {
+      int kMaxPushes = FLAG_optimize_for_size ? 4 : 32;
+      if (locals_count >= kMaxPushes) {
+        int loop_iterations = locals_count / kMaxPushes;
+        __ mov(r2, Operand(loop_iterations));
+        Label loop_header;
+        __ bind(&loop_header);
+        // Do pushes.
+        for (int i = 0; i < kMaxPushes; i++) {
           __ push(r9);
         }
+        // Continue loop if not done.
+        __ sub(r2, r2, Operand(1), SetCC);
+        __ b(&loop_header, ne);
+      }
+      int remaining = locals_count % kMaxPushes;
+      // Emit the remaining pushes.
+      for (int i  = 0; i < remaining; i++) {
+        __ push(r9);
       }
     }
   }
 
   bool function_in_register = true;
 
   // Possibly allocate a local context.
   int heap_slots = info->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
   if (heap_slots > 0) {
     // Argument to NewContext is the function, which is still in r1.
@@ skipping 90 matching lines @@
         ASSERT(function->proxy()->var()->mode() == CONST ||
                function->proxy()->var()->mode() == CONST_LEGACY);
         ASSERT(function->proxy()->var()->location() != Variable::UNALLOCATED);
         VisitVariableDeclaration(function);
       }
       VisitDeclarations(scope()->declarations());
     }
 
     { Comment cmnt(masm_, "[ Stack check");
       PrepareForBailoutForId(BailoutId::Declarations(), NO_REGISTERS);
-      Label ok;
-      __ LoadRoot(ip, Heap::kStackLimitRootIndex);
-      __ cmp(sp, Operand(ip));
-      __ b(hs, &ok);
-      PredictableCodeSizeScope predictable(masm_, 2 * Assembler::kInstrSize);
-      __ Call(isolate()->builtins()->StackCheck(), RelocInfo::CODE_TARGET);
-      __ bind(&ok);
+      EmitStackCheck(masm_, ip);
     }
 
     { Comment cmnt(masm_, "[ Body");
       ASSERT(loop_depth() == 0);
       VisitStatements(function()->body());
       ASSERT(loop_depth() == 0);
     }
   }
 
   // Always emit a 'return undefined' in case control fell off the end of
@@ skipping 4599 matching lines @@
 
   ASSERT(interrupt_address ==
          isolate->builtins()->OsrAfterStackCheck()->entry());
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM