Use count-based profiling exclusively.

src/arm/deoptimizer-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 96 matching lines @@
   ReplaceCodeForRelatedFunctions(function, code);
 
   if (FLAG_trace_deopt) {
     PrintF("[forced deoptimization: ");
     function->PrintName();
     PrintF(" / %x]\n", reinterpret_cast<uint32_t>(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,
                                         Code* replacement_code) {
   const int kInstrSize = Assembler::kInstrSize;
-  // The call of the stack guard check has the following form:
-  //  e1 5d 00 0c       cmp sp, <limit>
-  //  2a 00 00 01       bcs ok
+  // The back edge bookkeeping code matches the pattern:
+  //
+  //  <decrement profiling counter>
+  //  2a 00 00 01       bpl ok
   //  e5 9f c? ??       ldr ip, [pc, <stack guard address>]
   //  e1 2f ff 3c       blx ip
   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));
-  }
+  ASSERT_EQ(kBranchBeforeInterrupt,
+            Memory::int32_at(pc_after - 3 * kInstrSize));
 
   // We patch the code to the following form:
-  //  e1 5d 00 0c       cmp sp, <limit>
+  //
+  //  <decrement profiling counter>
   //  e1 a0 00 00       mov r0, r0 (NOP)
   //  e5 9f c? ??       ldr ip, [pc, <on-stack replacement address>]
   //  e1 2f ff 3c       blx ip
   // and overwrite the constant containing the
   // address of the stack check stub.
 
   // Replace conditional jump with NOP.
   CodePatcher patcher(pc_after - 3 * kInstrSize, 1);
   patcher.masm()->nop();
 
@@ skipping 16 matching lines @@
                                          Address pc_after,
                                          Code* check_code,
                                          Code* replacement_code) {
   const int kInstrSize = Assembler::kInstrSize;
   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);
-  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));
-  }
+  patcher.masm()->b(+16, pl);
+  ASSERT_EQ(kBranchBeforeInterrupt,
+            Memory::int32_at(pc_after - 3 * kInstrSize));
 
   // Replace the stack check address in the constant pool
   // with the entry address of the replacement code.
   uint32_t stack_check_address_offset = Memory::uint16_at(pc_after -
       2 * kInstrSize) & 0xfff;
   Address stack_check_address_pointer = pc_after + stack_check_address_offset;
   ASSERT(Memory::uint32_at(stack_check_address_pointer) ==
          reinterpret_cast<uint32_t>(replacement_code->entry()));
   Memory::uint32_at(stack_check_address_pointer) =
       reinterpret_cast<uint32_t>(check_code->entry());
@@ skipping 991 matching lines @@
     __ push(ip);
     __ b(&done);
     ASSERT(masm()->pc_offset() - start == table_entry_size_);
   }
   __ bind(&done);
 }
 
 #undef __
 
 } }  // namespace v8::internal