Initial support for count-based profiling

src/ia32/deoptimizer-ia32.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 187 matching lines @@
   function->ReplaceCode(function->shared()->code());
 
   if (FLAG_trace_deopt) {
     PrintF("[forced deoptimization: ");
     function->PrintName();
     PrintF(" / %x]\n", reinterpret_cast<uint32_t>(function));
   }
 }
 
 
+static const byte kJnsInstruction = 0x79;
+static const byte kJnsOffset = 0x11;
+static const byte kJaeInstruction = 0x73;
+static const byte kJaeOffset = 0x07;
+static const byte kCallInstruction = 0xe8;
+static const byte kNopByteOne = 0x66;
+static const byte kNopByteTwo = 0x90;
+
+
 void Deoptimizer::PatchStackCheckCodeAt(Code* unoptimized_code,
                                         Address pc_after,
                                         Code* check_code,
                                         Code* replacement_code) {
   Address call_target_address = pc_after - kIntSize;
   ASSERT(check_code->entry() ==
          Assembler::target_address_at(call_target_address));
   // The stack check code matches the pattern:
   //
   //     cmp esp, <limit>
   //     jae ok
   //     call <stack guard>
   //     test eax, <loop nesting depth>
   // ok: ...
   //
   // We will patch away the branch so the code is:
   //
   //     cmp esp, <limit>  ;; Not changed
   //     nop
   //     nop
   //     call <on-stack replacment>
   //     test eax, <loop nesting depth>
   // ok:
-  ASSERT(*(call_target_address - 3) == 0x73 &&  // jae
-         *(call_target_address - 2) == 0x07 &&  // offset
-         *(call_target_address - 1) == 0xe8);   // call
-  *(call_target_address - 3) = 0x66;  // 2 byte nop part 1
-  *(call_target_address - 2) = 0x90;  // 2 byte nop part 2
+
+  if (FLAG_count_based_interrupts) {
+    ASSERT(*(call_target_address - 3) == kJnsInstruction);
+    ASSERT(*(call_target_address - 2) == kJnsOffset);
+  } else {
+    ASSERT(*(call_target_address - 3) == kJaeInstruction);
+    ASSERT(*(call_target_address - 2) == kJaeOffset);
+  }
+  ASSERT(*(call_target_address - 1) == kCallInstruction);
+  *(call_target_address - 3) = kNopByteOne;
+  *(call_target_address - 2) = kNopByteTwo;
   Assembler::set_target_address_at(call_target_address,
                                    replacement_code->entry());
 
   unoptimized_code->GetHeap()->incremental_marking()->RecordCodeTargetPatch(
       unoptimized_code, call_target_address, replacement_code);
 }
 
 
 void Deoptimizer::RevertStackCheckCodeAt(Code* unoptimized_code,
                                          Address pc_after,
                                          Code* check_code,
                                          Code* replacement_code) {
   Address call_target_address = pc_after - kIntSize;
   ASSERT(replacement_code->entry() ==
          Assembler::target_address_at(call_target_address));
+
   // Replace the nops from patching (Deoptimizer::PatchStackCheckCode) to
   // restore the conditional branch.
-  ASSERT(*(call_target_address - 3) == 0x66 &&  // 2 byte nop part 1
-         *(call_target_address - 2) == 0x90 &&  // 2 byte nop part 2
-         *(call_target_address - 1) == 0xe8);   // call
-  *(call_target_address - 3) = 0x73;  // jae
-  *(call_target_address - 2) = 0x07;  // offset
+  ASSERT(*(call_target_address - 3) == kNopByteOne &&
+         *(call_target_address - 2) == kNopByteTwo &&
+         *(call_target_address - 1) == kCallInstruction);
+  if (FLAG_count_based_interrupts) {
+    *(call_target_address - 3) = kJnsInstruction;
+    *(call_target_address - 2) = kJnsOffset;
+  } else {
+    *(call_target_address - 3) = kJaeInstruction;
+    *(call_target_address - 2) = kJaeOffset;
+  }
   Assembler::set_target_address_at(call_target_address,
                                    check_code->entry());
 
   check_code->GetHeap()->incremental_marking()->RecordCodeTargetPatch(
       unoptimized_code, call_target_address, check_code);
 }
 
 
 static int LookupBailoutId(DeoptimizationInputData* data, unsigned ast_id) {
   ByteArray* translations = data->TranslationByteArray();
@@ skipping 649 matching lines @@
   }
   __ bind(&done);
 }
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32