MIPS: Port count-based profiler

src/mips/deoptimizer-mips.cc

 // Copyright 2011 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
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 }
 
 
 void Deoptimizer::PatchStackCheckCodeAt(Code* unoptimized_code,
                                         Address pc_after,
                                         Code* check_code,
                                         Code* replacement_code) {
   const int kInstrSize = Assembler::kInstrSize;
   // This structure comes from FullCodeGenerator::EmitStackCheck.
   // The call of the stack guard check has the following form:
-  // sltu at, sp, t0
+  // sltu at, sp, t0 / slt at, a3, zero_reg (in case of count based interrupts)
   // beq at, zero_reg, ok
   // lui t9, <stack guard address> upper
   // ori t9, <stack guard address> lower
   // jalr t9
   // nop
   // ----- pc_after points here
 
   ASSERT(Assembler::IsBeq(Assembler::instr_at(pc_after - 5 * kInstrSize)));
 
   // Replace the sltu instruction with load-imm 1 to at, so beq is not taken.
@@ skipping 27 matching lines @@
                                          Code* check_code,
                                          Code* replacement_code) {
   // Exact opposite of the function above.
   const int kInstrSize = Assembler::kInstrSize;
   ASSERT(Assembler::IsAddImmediate(
       Assembler::instr_at(pc_after - 6 * kInstrSize)));
   ASSERT(Assembler::IsBeq(Assembler::instr_at(pc_after - 5 * kInstrSize)));
 
   // Restore the sltu instruction so beq can be taken again.
   CodePatcher patcher(pc_after - 6 * kInstrSize, 1);
-  patcher.masm()->sltu(at, sp, t0);
+  if (FLAG_count_based_interrupts) {
+    patcher.masm()->slt(at, a3, zero_reg);
+  } else {
+    patcher.masm()->sltu(at, sp, t0);
+  }
 
   // Replace the on-stack replacement address in the load-immediate (lui/ori
   // pair) with the entry address of the normal stack-check code.
   ASSERT(reinterpret_cast<uint32_t>(
       Assembler::target_address_at(pc_after - 4 * kInstrSize)) ==
       reinterpret_cast<uint32_t>(replacement_code->entry()));
   Assembler::set_target_address_at(pc_after - 4 * kInstrSize,
                                    check_code->entry());
 
   check_code->GetHeap()->incremental_marking()->RecordCodeTargetPatch(
@@ skipping 798 matching lines @@
   }
 
   ASSERT_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
       count() * table_entry_size_);
 }
 
 #undef __
 
 
 } }  // namespace v8::internal