Port count-based profiler to ARM

Review URL: https://chromiumcodereview.appspot.com/9837004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11120 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/assembler-arm.cc

@@ -257,6 +257,7 @@ const Instr kBlxRegMask =
     15 * B24 | 15 * B20 | 15 * B16 | 15 * B12 | 15 * B8 | 15 * B4;
 const Instr kBlxRegPattern =
     B24 | B21 | 15 * B16 | 15 * B12 | 15 * B8 | BLX;
+const Instr kBlxIp = al | kBlxRegPattern | ip.code();
 const Instr kMovMvnMask = 0x6d * B21 | 0xf * B16;
 const Instr kMovMvnPattern = 0xd * B21;
 const Instr kMovMvnFlip = B22;

src/arm/assembler-arm.h

@@ -604,6 +604,7 @@ extern const Instr kLdrPCMask;
 extern const Instr kLdrPCPattern;
 extern const Instr kBlxRegMask;
 extern const Instr kBlxRegPattern;
+extern const Instr kBlxIp;
 
 extern const Instr kMovMvnMask;
 extern const Instr kMovMvnPattern;

src/arm/deoptimizer-arm.cc

@@ -108,6 +108,10 @@ void Deoptimizer::DeoptimizeFunction(JSFunction* function) {
 }
 
 
+static const int32_t kBranchBeforeStackCheck = 0x2a000001;
+static const int32_t kBranchBeforeInterrupt =  0x5a000004;
+
+
 void Deoptimizer::PatchStackCheckCodeAt(Code* unoptimized_code,
                                         Address pc_after,
                                         Code* check_code,
@@ -118,10 +122,16 @@ void Deoptimizer::PatchStackCheckCodeAt(Code* unoptimized_code,
   //  2a 00 00 01       bcs ok
   //  e5 9f c? ??       ldr ip, [pc, <stack guard address>]
   //  e1 2f ff 3c       blx ip
-  ASSERT(Memory::int32_at(pc_after - kInstrSize) ==
-      (al | B24 | B21 | 15*B16 | 15*B12 | 15*B8 | BLX | ip.code()));
+  ASSERT(Memory::int32_at(pc_after - kInstrSize) == kBlxIp);
   ASSERT(Assembler::IsLdrPcImmediateOffset(
       Assembler::instr_at(pc_after - 2 * kInstrSize)));
+  if (FLAG_count_based_interrupts) {
+    ASSERT_EQ(kBranchBeforeInterrupt,
+              Memory::int32_at(pc_after - 3 * kInstrSize));
+  } else {
+    ASSERT_EQ(kBranchBeforeStackCheck,
+              Memory::int32_at(pc_after - 3 * kInstrSize));
+  }
 
   // We patch the code to the following form:
   //  e1 5d 00 0c       cmp sp, <limit>
@@ -155,13 +165,21 @@ void Deoptimizer::RevertStackCheckCodeAt(Code* unoptimized_code,
                                          Code* check_code,
                                          Code* replacement_code) {
   const int kInstrSize = Assembler::kInstrSize;
-  ASSERT(Memory::uint32_at(pc_after - kInstrSize) == 0xe12fff3c);
-  ASSERT(Memory::uint8_at(pc_after - kInstrSize - 1) == 0xe5);
-  ASSERT(Memory::uint8_at(pc_after - kInstrSize - 2) == 0x9f);
+  ASSERT(Memory::int32_at(pc_after - kInstrSize) == kBlxIp);
+  ASSERT(Assembler::IsLdrPcImmediateOffset(
+      Assembler::instr_at(pc_after - 2 * kInstrSize)));
 
   // Replace NOP with conditional jump.
   CodePatcher patcher(pc_after - 3 * kInstrSize, 1);
-  patcher.masm()->b(+4, cs);
+  if (FLAG_count_based_interrupts) {
+    patcher.masm()->b(+16, pl);
+    ASSERT_EQ(kBranchBeforeInterrupt,
+              Memory::int32_at(pc_after - 3 * kInstrSize));
+  } else {
+    patcher.masm()->b(+4, cs);
+    ASSERT_EQ(kBranchBeforeStackCheck,
+              Memory::int32_at(pc_after - 3 * kInstrSize));
+  }
 
   // Replace the stack check address in the constant pool
   // with the entry address of the replacement code.

src/ia32/full-codegen-ia32.cc

@@ -34,6 +34,7 @@
 #include "compiler.h"
 #include "debug.h"
 #include "full-codegen.h"
+#include "isolate-inl.h"
 #include "parser.h"
 #include "scopes.h"
 #include "stub-cache.h"
@@ -100,7 +101,9 @@ class JumpPatchSite BASE_EMBEDDED {
 };
 
 
+// TODO(jkummerow): Obsolete as soon as x64 is updated. Remove.
 int FullCodeGenerator::self_optimization_header_size() {
+  UNREACHABLE();
   return 13;
 }
 
@@ -321,12 +324,20 @@ void FullCodeGenerator::EmitProfilingCounterReset() {
     // Self-optimization is a one-off thing: if it fails, don't try again.
     reset_value = Smi::kMaxValue;
   }
+  if (isolate()->IsDebuggerActive()) {
+    // Detect debug break requests as soon as possible.
+    reset_value = 10;
+  }
   __ mov(ebx, Immediate(profiling_counter_));
   __ mov(FieldOperand(ebx, JSGlobalPropertyCell::kValueOffset),
          Immediate(Smi::FromInt(reset_value)));
 }
 
 
+static const int kMaxBackEdgeWeight = 127;
+static const int kBackEdgeDistanceDivisor = 100;
+
+
 void FullCodeGenerator::EmitStackCheck(IterationStatement* stmt,
                                        Label* back_edge_target) {
   Comment cmnt(masm_, "[ Stack check");
@@ -337,7 +348,8 @@ void FullCodeGenerator::EmitStackCheck(IterationStatement* stmt,
     if (FLAG_weighted_back_edges) {
       ASSERT(back_edge_target->is_bound());
       int distance = masm_->SizeOfCodeGeneratedSince(back_edge_target);
-      weight = Min(127, Max(1, distance / 100));
+      weight = Min(kMaxBackEdgeWeight,
+                   Max(1, distance / kBackEdgeDistanceDivisor));
     }
     EmitProfilingCounterDecrement(weight);
     __ j(positive, &ok, Label::kNear);
@@ -398,7 +410,8 @@ void FullCodeGenerator::EmitReturnSequence() {
         weight = FLAG_interrupt_budget / FLAG_self_opt_count;
       } else if (FLAG_weighted_back_edges) {
         int distance = masm_->pc_offset();
-        weight = Min(127, Max(1, distance / 100));
+        weight = Min(kMaxBackEdgeWeight,
+                     Max(1, distance / kBackEdgeDistanceDivisor));
       }
       EmitProfilingCounterDecrement(weight);
       Label ok;

src/isolate-inl.h

@@ -49,6 +49,16 @@ SaveContext::SaveContext(Isolate* isolate) : prev_(isolate->save_context()) {
 }
 
 
+bool Isolate::IsDebuggerActive() {
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  if (!NoBarrier_Load(&debugger_initialized_)) return false;
+  return debugger()->IsDebuggerActive();
+#else
+  return false;
+#endif
+}
+
+
 bool Isolate::DebuggerHasBreakPoints() {
 #ifdef ENABLE_DEBUGGER_SUPPORT
   return debug()->has_break_points();

src/isolate.h

@@ -929,6 +929,7 @@ class Isolate {
   }
 #endif
 
+  inline bool IsDebuggerActive();
   inline bool DebuggerHasBreakPoints();
 
 #ifdef DEBUG

src/runtime-profiler.cc

@@ -173,7 +173,7 @@ void RuntimeProfiler::AttemptOnStackReplacement(JSFunction* function) {
   // prepared to generate it, but we don't expect to have to.
   bool found_code = false;
   Code* stack_check_code = NULL;
-#ifdef V8_TARGET_ARCH_IA32
+#if defined(V8_TARGET_ARCH_IA32) || defined(V8_TARGET_ARCH_ARM)
   if (FLAG_count_based_interrupts) {
     InterruptStub interrupt_stub;
     found_code = interrupt_stub.FindCodeInCache(&stack_check_code);
@@ -349,7 +349,7 @@ void RuntimeProfiler::OptimizeNow() {
 
 
 void RuntimeProfiler::NotifyTick() {
-#ifdef V8_TARGET_ARCH_IA32
+#if defined(V8_TARGET_ARCH_IA32) || defined(V8_TARGET_ARCH_ARM)
   if (FLAG_count_based_interrupts) return;
 #endif
   isolate_->stack_guard()->RequestRuntimeProfilerTick();

src/runtime.cc

@@ -8366,7 +8366,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_CompileForOnStackReplacement) {
     PrintF("]\n");
   }
   Handle<Code> check_code;
-#ifdef V8_TARGET_ARCH_IA32
+#if defined(V8_TARGET_ARCH_IA32) || defined(V8_TARGET_ARCH_ARM)
   if (FLAG_count_based_interrupts) {
     InterruptStub interrupt_stub;
     check_code = interrupt_stub.GetCode();