Port count-based profiler to x64

src/x64/deoptimizer-x64.cc

Index: src/x64/deoptimizer-x64.cc
diff --git a/src/x64/deoptimizer-x64.cc b/src/x64/deoptimizer-x64.cc
index 2adf587f8c47799cf52c3d7c4e2e787d00d89d49..b966669189586161e001dcc980bbbddbcde24b56 100644
--- a/src/x64/deoptimizer-x64.cc
+++ b/src/x64/deoptimizer-x64.cc
@@ -111,13 +111,22 @@ void Deoptimizer::DeoptimizeFunction(JSFunction* function) {
 }
 
 
+static const byte kJnsInstruction = 0x79;
+static const byte kJnsOffset = 0x1f;
+static const byte kJnsOffsetDebugCode = 0x53;
+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));
+  ASSERT_EQ(check_code->entry(),
+            Assembler::target_address_at(call_target_address));
   // The stack check code matches the pattern:
   //
   //     cmp rsp, <limit>
@@ -135,11 +144,24 @@ void Deoptimizer::PatchStackCheckCodeAt(Code* unoptimized_code,
   //     test rax, <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_EQ(kJnsInstruction,       *(call_target_address - 3));
+    if (FLAG_debug_code) {
+      // FullCodeGenerator::EmitProfilingCounterReset() makes use of
+      // masm->Move(Operand&, Smi*), which generates additional code
+      // when FLAG_debug_code is set, so the jump offset is larger
+      // in that case.
+      ASSERT_EQ(kJnsOffsetDebugCode, *(call_target_address - 2));
+    } else {
+      ASSERT_EQ(kJnsOffset,          *(call_target_address - 2));
+    }
+  } else {
+    ASSERT_EQ(kJaeInstruction,       *(call_target_address - 3));
+    ASSERT_EQ(kJaeOffset,            *(call_target_address - 2));
+  }
+  ASSERT_EQ(kCallInstruction,        *(call_target_address - 1));
+  *(call_target_address - 3) = kNopByteOne;
+  *(call_target_address - 2) = kNopByteTwo;
   Assembler::set_target_address_at(call_target_address,
                                    replacement_code->entry());
 
@@ -157,11 +179,21 @@ void Deoptimizer::RevertStackCheckCodeAt(Code* unoptimized_code,
          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_EQ(kNopByteOne,      *(call_target_address - 3));
+  ASSERT_EQ(kNopByteTwo,      *(call_target_address - 2));
+  ASSERT_EQ(kCallInstruction, *(call_target_address - 1));
+  if (FLAG_count_based_interrupts) {
+    *(call_target_address - 3) = kJnsInstruction;
+    if (FLAG_debug_code) {
+      // See comment above: larger jump offset if debug code is generated.
+      *(call_target_address - 2) = kJnsOffsetDebugCode;
+    } else {
+      *(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());