Compiler: Spring cleaning

Significant restructuring of the Quick compiler to break out the
common frontend more cleanly.  Additional C++'ification.

The goal is to move from the monolithic structure of the old
JIT towards a more modular model in which components - in
particular the compiler backend - can be replaced.  This CL
focuses on moving MIR-related data from the CompilationUnit
struct into a new MIRGraph class.  The next CL will isolate all
LIR-related data and code down into the Quick backend.

This change will happen in multiple steps, and may look uglier
before it starts looking better.

Among the changes:

   o Moved all mir-related fields from CompilationUnit to new
     MirGraph class.

   o Moved the register promotion stuff into the Quick backend.

   o Deleted the GBC to LIR conversion code.

   o Replaced with old C-style function pointer dataflow analysis
     dispatcher with a basic block iterator class.

   o Renamed some files to make the name more consistent with what
     the code actually does.

   o Added the foundation for future inlining support.

   o Stripped out the remains of the old fingerprinting mechanism.

Change-Id: I6c30facc642f8084b1c7b2075cf7014de387aa56
diff --git a/src/compiler/dex/mir_graph.cc b/src/compiler/dex/mir_graph.cc
new file mode 100644
index 0000000..71aaa38
--- /dev/null
+++ b/src/compiler/dex/mir_graph.cc
@@ -0,0 +1,840 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "compiler_internals.h"
+#include "mir_graph.h"
+#include "leb128.h"
+#include "dex_file-inl.h"
+
+namespace art {
+
+#define MAX_PATTERN_LEN 5
+
+struct CodePattern {
+  const Instruction::Code opcodes[MAX_PATTERN_LEN];
+  const SpecialCaseHandler handler_code;
+};
+
+static const CodePattern special_patterns[] = {
+  {{Instruction::RETURN_VOID}, kNullMethod},
+  {{Instruction::CONST, Instruction::RETURN}, kConstFunction},
+  {{Instruction::CONST_4, Instruction::RETURN}, kConstFunction},
+  {{Instruction::CONST_4, Instruction::RETURN_OBJECT}, kConstFunction},
+  {{Instruction::CONST_16, Instruction::RETURN}, kConstFunction},
+  {{Instruction::IGET, Instruction:: RETURN}, kIGet},
+  {{Instruction::IGET_BOOLEAN, Instruction::RETURN}, kIGetBoolean},
+  {{Instruction::IGET_OBJECT, Instruction::RETURN_OBJECT}, kIGetObject},
+  {{Instruction::IGET_BYTE, Instruction::RETURN}, kIGetByte},
+  {{Instruction::IGET_CHAR, Instruction::RETURN}, kIGetChar},
+  {{Instruction::IGET_SHORT, Instruction::RETURN}, kIGetShort},
+  {{Instruction::IGET_WIDE, Instruction::RETURN_WIDE}, kIGetWide},
+  {{Instruction::IPUT, Instruction::RETURN_VOID}, kIPut},
+  {{Instruction::IPUT_BOOLEAN, Instruction::RETURN_VOID}, kIPutBoolean},
+  {{Instruction::IPUT_OBJECT, Instruction::RETURN_VOID}, kIPutObject},
+  {{Instruction::IPUT_BYTE, Instruction::RETURN_VOID}, kIPutByte},
+  {{Instruction::IPUT_CHAR, Instruction::RETURN_VOID}, kIPutChar},
+  {{Instruction::IPUT_SHORT, Instruction::RETURN_VOID}, kIPutShort},
+  {{Instruction::IPUT_WIDE, Instruction::RETURN_VOID}, kIPutWide},
+  {{Instruction::RETURN}, kIdentity},
+  {{Instruction::RETURN_OBJECT}, kIdentity},
+  {{Instruction::RETURN_WIDE}, kIdentity},
+};
+
+MIRGraph::MIRGraph(CompilationUnit* cu)
+    : cu_(cu),
+      ssa_base_vregs_(NULL),
+      ssa_subscripts_(NULL),
+      ssa_strings_(NULL),
+      vreg_to_ssa_map_(NULL),
+      ssa_last_defs_(NULL),
+      is_constant_v_(NULL),
+      constant_values_(NULL),
+      num_reachable_blocks_(0),
+      i_dom_list_(NULL),
+      def_block_matrix_(NULL),
+      temp_block_v_(NULL),
+      temp_dalvik_register_v_(NULL),
+      temp_ssa_register_v_(NULL),
+      try_block_addr_(NULL),
+      entry_block_(NULL),
+      exit_block_(NULL),
+      cur_block_(NULL),
+      num_blocks_(0),
+      current_code_item_(NULL),
+      current_method_(kInvalidEntry),
+      current_offset_(kInvalidEntry),
+      def_count_(0),
+      opcode_count_(NULL),
+      num_ssa_regs_(0) {
+  CompilerInitGrowableList(cu, &block_list_, 0, kListBlockList);
+  try_block_addr_ = AllocBitVector(cu, 0, true /* expandable */);
+}
+
+bool MIRGraph::ContentIsInsn(const uint16_t* code_ptr) {
+  uint16_t instr = *code_ptr;
+  Instruction::Code opcode = static_cast<Instruction::Code>(instr & 0xff);
+  /*
+   * Since the low 8-bit in metadata may look like NOP, we need to check
+   * both the low and whole sub-word to determine whether it is code or data.
+   */
+  return (opcode != Instruction::NOP || instr == 0);
+}
+
+/*
+ * Parse an instruction, return the length of the instruction
+ */
+int MIRGraph::ParseInsn(const uint16_t* code_ptr, DecodedInstruction* decoded_instruction)
+{
+  // Don't parse instruction data
+  if (!ContentIsInsn(code_ptr)) {
+    return 0;
+  }
+
+  const Instruction* instruction = Instruction::At(code_ptr);
+  *decoded_instruction = DecodedInstruction(instruction);
+
+  return instruction->SizeInCodeUnits();
+}
+
+
+/* Split an existing block from the specified code offset into two */
+BasicBlock* MIRGraph::SplitBlock(unsigned int code_offset,
+                                 BasicBlock* orig_block, BasicBlock** immed_pred_block_p)
+{
+  MIR* insn = orig_block->first_mir_insn;
+  while (insn) {
+    if (insn->offset == code_offset) break;
+    insn = insn->next;
+  }
+  if (insn == NULL) {
+    LOG(FATAL) << "Break split failed";
+  }
+  BasicBlock *bottom_block = NewMemBB(cu_, kDalvikByteCode, num_blocks_++);
+  InsertGrowableList(cu_, &block_list_, reinterpret_cast<uintptr_t>(bottom_block));
+
+  bottom_block->start_offset = code_offset;
+  bottom_block->first_mir_insn = insn;
+  bottom_block->last_mir_insn = orig_block->last_mir_insn;
+
+  /* If this block was terminated by a return, the flag needs to go with the bottom block */
+  bottom_block->terminated_by_return = orig_block->terminated_by_return;
+  orig_block->terminated_by_return = false;
+
+  /* Add it to the quick lookup cache */
+  block_map_.Put(bottom_block->start_offset, bottom_block);
+
+  /* Handle the taken path */
+  bottom_block->taken = orig_block->taken;
+  if (bottom_block->taken) {
+    orig_block->taken = NULL;
+    DeleteGrowableList(bottom_block->taken->predecessors, reinterpret_cast<uintptr_t>(orig_block));
+    InsertGrowableList(cu_, bottom_block->taken->predecessors,
+                          reinterpret_cast<uintptr_t>(bottom_block));
+  }
+
+  /* Handle the fallthrough path */
+  bottom_block->fall_through = orig_block->fall_through;
+  orig_block->fall_through = bottom_block;
+  InsertGrowableList(cu_, bottom_block->predecessors,
+                        reinterpret_cast<uintptr_t>(orig_block));
+  if (bottom_block->fall_through) {
+    DeleteGrowableList(bottom_block->fall_through->predecessors,
+                          reinterpret_cast<uintptr_t>(orig_block));
+    InsertGrowableList(cu_, bottom_block->fall_through->predecessors,
+                          reinterpret_cast<uintptr_t>(bottom_block));
+  }
+
+  /* Handle the successor list */
+  if (orig_block->successor_block_list.block_list_type != kNotUsed) {
+    bottom_block->successor_block_list = orig_block->successor_block_list;
+    orig_block->successor_block_list.block_list_type = kNotUsed;
+    GrowableListIterator iterator;
+
+    GrowableListIteratorInit(&bottom_block->successor_block_list.blocks,
+                                &iterator);
+    while (true) {
+      SuccessorBlockInfo *successor_block_info =
+          reinterpret_cast<SuccessorBlockInfo*>(GrowableListIteratorNext(&iterator));
+      if (successor_block_info == NULL) break;
+      BasicBlock *bb = successor_block_info->block;
+      DeleteGrowableList(bb->predecessors, reinterpret_cast<uintptr_t>(orig_block));
+      InsertGrowableList(cu_, bb->predecessors, reinterpret_cast<uintptr_t>(bottom_block));
+    }
+  }
+
+  orig_block->last_mir_insn = insn->prev;
+
+  insn->prev->next = NULL;
+  insn->prev = NULL;
+  /*
+   * Update the immediate predecessor block pointer so that outgoing edges
+   * can be applied to the proper block.
+   */
+  if (immed_pred_block_p) {
+    DCHECK_EQ(*immed_pred_block_p, orig_block);
+    *immed_pred_block_p = bottom_block;
+  }
+  return bottom_block;
+}
+
+/*
+ * Given a code offset, find out the block that starts with it. If the offset
+ * is in the middle of an existing block, split it into two.  If immed_pred_block_p
+ * is not non-null and is the block being split, update *immed_pred_block_p to
+ * point to the bottom block so that outgoing edges can be set up properly
+ * (by the caller)
+ * Utilizes a map for fast lookup of the typical cases.
+ */
+BasicBlock* MIRGraph::FindBlock(unsigned int code_offset, bool split, bool create,
+                                BasicBlock** immed_pred_block_p)
+{
+  BasicBlock* bb;
+  unsigned int i;
+  SafeMap<unsigned int, BasicBlock*>::iterator it;
+
+  it = block_map_.find(code_offset);
+  if (it != block_map_.end()) {
+    return it->second;
+  } else if (!create) {
+    return NULL;
+  }
+
+  if (split) {
+    for (i = 0; i < block_list_.num_used; i++) {
+      bb = reinterpret_cast<BasicBlock*>(block_list_.elem_list[i]);
+      if (bb->block_type != kDalvikByteCode) continue;
+      /* Check if a branch jumps into the middle of an existing block */
+      if ((code_offset > bb->start_offset) && (bb->last_mir_insn != NULL) &&
+          (code_offset <= bb->last_mir_insn->offset)) {
+        BasicBlock *new_bb = SplitBlock(code_offset, bb, bb == *immed_pred_block_p ?
+                                       immed_pred_block_p : NULL);
+        return new_bb;
+      }
+    }
+  }
+
+  /* Create a new one */
+  bb = NewMemBB(cu_, kDalvikByteCode, num_blocks_++);
+  InsertGrowableList(cu_, &block_list_, reinterpret_cast<uintptr_t>(bb));
+  bb->start_offset = code_offset;
+  block_map_.Put(bb->start_offset, bb);
+  return bb;
+}
+
+/* Identify code range in try blocks and set up the empty catch blocks */
+void MIRGraph::ProcessTryCatchBlocks()
+{
+  int tries_size = current_code_item_->tries_size_;
+  int offset;
+
+  if (tries_size == 0) {
+    return;
+  }
+
+  for (int i = 0; i < tries_size; i++) {
+    const DexFile::TryItem* pTry =
+        DexFile::GetTryItems(*current_code_item_, i);
+    int start_offset = pTry->start_addr_;
+    int end_offset = start_offset + pTry->insn_count_;
+    for (offset = start_offset; offset < end_offset; offset++) {
+      SetBit(cu_, try_block_addr_, offset);
+    }
+  }
+
+  // Iterate over each of the handlers to enqueue the empty Catch blocks
+  const byte* handlers_ptr = DexFile::GetCatchHandlerData(*current_code_item_, 0);
+  uint32_t handlers_size = DecodeUnsignedLeb128(&handlers_ptr);
+  for (uint32_t idx = 0; idx < handlers_size; idx++) {
+    CatchHandlerIterator iterator(handlers_ptr);
+    for (; iterator.HasNext(); iterator.Next()) {
+      uint32_t address = iterator.GetHandlerAddress();
+      FindBlock(address, false /* split */, true /*create*/,
+                /* immed_pred_block_p */ NULL);
+    }
+    handlers_ptr = iterator.EndDataPointer();
+  }
+}
+
+/* Process instructions with the kBranch flag */
+BasicBlock* MIRGraph::ProcessCanBranch(BasicBlock* cur_block, MIR* insn, int cur_offset, int width,
+                                       int flags, const uint16_t* code_ptr,
+                                       const uint16_t* code_end)
+{
+  int target = cur_offset;
+  switch (insn->dalvikInsn.opcode) {
+    case Instruction::GOTO:
+    case Instruction::GOTO_16:
+    case Instruction::GOTO_32:
+      target += insn->dalvikInsn.vA;
+      break;
+    case Instruction::IF_EQ:
+    case Instruction::IF_NE:
+    case Instruction::IF_LT:
+    case Instruction::IF_GE:
+    case Instruction::IF_GT:
+    case Instruction::IF_LE:
+      cur_block->conditional_branch = true;
+      target += insn->dalvikInsn.vC;
+      break;
+    case Instruction::IF_EQZ:
+    case Instruction::IF_NEZ:
+    case Instruction::IF_LTZ:
+    case Instruction::IF_GEZ:
+    case Instruction::IF_GTZ:
+    case Instruction::IF_LEZ:
+      cur_block->conditional_branch = true;
+      target += insn->dalvikInsn.vB;
+      break;
+    default:
+      LOG(FATAL) << "Unexpected opcode(" << insn->dalvikInsn.opcode << ") with kBranch set";
+  }
+  BasicBlock *taken_block = FindBlock(target, /* split */ true, /* create */ true,
+                                      /* immed_pred_block_p */ &cur_block);
+  cur_block->taken = taken_block;
+  InsertGrowableList(cu_, taken_block->predecessors, reinterpret_cast<uintptr_t>(cur_block));
+
+  /* Always terminate the current block for conditional branches */
+  if (flags & Instruction::kContinue) {
+    BasicBlock *fallthrough_block = FindBlock(cur_offset +  width,
+                                             /*
+                                              * If the method is processed
+                                              * in sequential order from the
+                                              * beginning, we don't need to
+                                              * specify split for continue
+                                              * blocks. However, this
+                                              * routine can be called by
+                                              * compileLoop, which starts
+                                              * parsing the method from an
+                                              * arbitrary address in the
+                                              * method body.
+                                              */
+                                             true,
+                                             /* create */
+                                             true,
+                                             /* immed_pred_block_p */
+                                             &cur_block);
+    cur_block->fall_through = fallthrough_block;
+    InsertGrowableList(cu_, fallthrough_block->predecessors,
+                          reinterpret_cast<uintptr_t>(cur_block));
+  } else if (code_ptr < code_end) {
+    /* Create a fallthrough block for real instructions (incl. NOP) */
+    if (ContentIsInsn(code_ptr)) {
+      FindBlock(cur_offset + width, /* split */ false, /* create */ true,
+                /* immed_pred_block_p */ NULL);
+    }
+  }
+  return cur_block;
+}
+
+/* Process instructions with the kSwitch flag */
+void MIRGraph::ProcessCanSwitch(BasicBlock* cur_block, MIR* insn, int cur_offset, int width,
+                                int flags)
+{
+  const uint16_t* switch_data =
+      reinterpret_cast<const uint16_t*>(GetCurrentInsns() + cur_offset + insn->dalvikInsn.vB);
+  int size;
+  const int* keyTable;
+  const int* target_table;
+  int i;
+  int first_key;
+
+  /*
+   * Packed switch data format:
+   *  ushort ident = 0x0100   magic value
+   *  ushort size             number of entries in the table
+   *  int first_key           first (and lowest) switch case value
+   *  int targets[size]       branch targets, relative to switch opcode
+   *
+   * Total size is (4+size*2) 16-bit code units.
+   */
+  if (insn->dalvikInsn.opcode == Instruction::PACKED_SWITCH) {
+    DCHECK_EQ(static_cast<int>(switch_data[0]),
+              static_cast<int>(Instruction::kPackedSwitchSignature));
+    size = switch_data[1];
+    first_key = switch_data[2] | (switch_data[3] << 16);
+    target_table = reinterpret_cast<const int*>(&switch_data[4]);
+    keyTable = NULL;        // Make the compiler happy
+  /*
+   * Sparse switch data format:
+   *  ushort ident = 0x0200   magic value
+   *  ushort size             number of entries in the table; > 0
+   *  int keys[size]          keys, sorted low-to-high; 32-bit aligned
+   *  int targets[size]       branch targets, relative to switch opcode
+   *
+   * Total size is (2+size*4) 16-bit code units.
+   */
+  } else {
+    DCHECK_EQ(static_cast<int>(switch_data[0]),
+              static_cast<int>(Instruction::kSparseSwitchSignature));
+    size = switch_data[1];
+    keyTable = reinterpret_cast<const int*>(&switch_data[2]);
+    target_table = reinterpret_cast<const int*>(&switch_data[2 + size*2]);
+    first_key = 0;   // To make the compiler happy
+  }
+
+  if (cur_block->successor_block_list.block_list_type != kNotUsed) {
+    LOG(FATAL) << "Successor block list already in use: "
+               << static_cast<int>(cur_block->successor_block_list.block_list_type);
+  }
+  cur_block->successor_block_list.block_list_type =
+      (insn->dalvikInsn.opcode == Instruction::PACKED_SWITCH) ?
+      kPackedSwitch : kSparseSwitch;
+  CompilerInitGrowableList(cu_, &cur_block->successor_block_list.blocks, size,
+                      kListSuccessorBlocks);
+
+  for (i = 0; i < size; i++) {
+    BasicBlock *case_block = FindBlock(cur_offset + target_table[i], /* split */ true,
+                                      /* create */ true, /* immed_pred_block_p */ &cur_block);
+    SuccessorBlockInfo *successor_block_info =
+        static_cast<SuccessorBlockInfo*>(NewMem(cu_, sizeof(SuccessorBlockInfo),
+                                         false, kAllocSuccessor));
+    successor_block_info->block = case_block;
+    successor_block_info->key =
+        (insn->dalvikInsn.opcode == Instruction::PACKED_SWITCH) ?
+        first_key + i : keyTable[i];
+    InsertGrowableList(cu_, &cur_block->successor_block_list.blocks,
+                          reinterpret_cast<uintptr_t>(successor_block_info));
+    InsertGrowableList(cu_, case_block->predecessors,
+                          reinterpret_cast<uintptr_t>(cur_block));
+  }
+
+  /* Fall-through case */
+  BasicBlock* fallthrough_block = FindBlock( cur_offset +  width, /* split */ false,
+                                           /* create */ true, /* immed_pred_block_p */ NULL);
+  cur_block->fall_through = fallthrough_block;
+  InsertGrowableList(cu_, fallthrough_block->predecessors,
+                        reinterpret_cast<uintptr_t>(cur_block));
+}
+
+/* Process instructions with the kThrow flag */
+BasicBlock* MIRGraph::ProcessCanThrow(BasicBlock* cur_block, MIR* insn, int cur_offset, int width,
+                                      int flags, ArenaBitVector* try_block_addr,
+                                      const uint16_t* code_ptr, const uint16_t* code_end)
+{
+  bool in_try_block = IsBitSet(try_block_addr, cur_offset);
+
+  /* In try block */
+  if (in_try_block) {
+    CatchHandlerIterator iterator(*current_code_item_, cur_offset);
+
+    if (cur_block->successor_block_list.block_list_type != kNotUsed) {
+      LOG(INFO) << PrettyMethod(cu_->method_idx, *cu_->dex_file);
+      LOG(FATAL) << "Successor block list already in use: "
+                 << static_cast<int>(cur_block->successor_block_list.block_list_type);
+    }
+
+    cur_block->successor_block_list.block_list_type = kCatch;
+    CompilerInitGrowableList(cu_, &cur_block->successor_block_list.blocks, 2,
+                        kListSuccessorBlocks);
+
+    for (;iterator.HasNext(); iterator.Next()) {
+      BasicBlock *catch_block = FindBlock(iterator.GetHandlerAddress(), false /* split*/,
+                                         false /* creat */, NULL  /* immed_pred_block_p */);
+      catch_block->catch_entry = true;
+      if (kIsDebugBuild) {
+        catches_.insert(catch_block->start_offset);
+      }
+      SuccessorBlockInfo *successor_block_info = reinterpret_cast<SuccessorBlockInfo*>
+          (NewMem(cu_, sizeof(SuccessorBlockInfo), false, kAllocSuccessor));
+      successor_block_info->block = catch_block;
+      successor_block_info->key = iterator.GetHandlerTypeIndex();
+      InsertGrowableList(cu_, &cur_block->successor_block_list.blocks,
+                            reinterpret_cast<uintptr_t>(successor_block_info));
+      InsertGrowableList(cu_, catch_block->predecessors,
+                            reinterpret_cast<uintptr_t>(cur_block));
+    }
+  } else {
+    BasicBlock *eh_block = NewMemBB(cu_, kExceptionHandling, num_blocks_++);
+    cur_block->taken = eh_block;
+    InsertGrowableList(cu_, &block_list_, reinterpret_cast<uintptr_t>(eh_block));
+    eh_block->start_offset = cur_offset;
+    InsertGrowableList(cu_, eh_block->predecessors, reinterpret_cast<uintptr_t>(cur_block));
+  }
+
+  if (insn->dalvikInsn.opcode == Instruction::THROW){
+    cur_block->explicit_throw = true;
+    if ((code_ptr < code_end) && ContentIsInsn(code_ptr)) {
+      // Force creation of new block following THROW via side-effect
+      FindBlock(cur_offset + width, /* split */ false, /* create */ true,
+                /* immed_pred_block_p */ NULL);
+    }
+    if (!in_try_block) {
+       // Don't split a THROW that can't rethrow - we're done.
+      return cur_block;
+    }
+  }
+
+  /*
+   * Split the potentially-throwing instruction into two parts.
+   * The first half will be a pseudo-op that captures the exception
+   * edges and terminates the basic block.  It always falls through.
+   * Then, create a new basic block that begins with the throwing instruction
+   * (minus exceptions).  Note: this new basic block must NOT be entered into
+   * the block_map.  If the potentially-throwing instruction is the target of a
+   * future branch, we need to find the check psuedo half.  The new
+   * basic block containing the work portion of the instruction should
+   * only be entered via fallthrough from the block containing the
+   * pseudo exception edge MIR.  Note also that this new block is
+   * not automatically terminated after the work portion, and may
+   * contain following instructions.
+   */
+  BasicBlock *new_block = NewMemBB(cu_, kDalvikByteCode, num_blocks_++);
+  InsertGrowableList(cu_, &block_list_, reinterpret_cast<uintptr_t>(new_block));
+  new_block->start_offset = insn->offset;
+  cur_block->fall_through = new_block;
+  InsertGrowableList(cu_, new_block->predecessors, reinterpret_cast<uintptr_t>(cur_block));
+  MIR* new_insn = static_cast<MIR*>(NewMem(cu_, sizeof(MIR), true, kAllocMIR));
+  *new_insn = *insn;
+  insn->dalvikInsn.opcode =
+      static_cast<Instruction::Code>(kMirOpCheck);
+  // Associate the two halves
+  insn->meta.throw_insn = new_insn;
+  new_insn->meta.throw_insn = insn;
+  AppendMIR(new_block, new_insn);
+  return new_block;
+}
+
+/* Parse a Dex method and insert it into the MIRGraph at the current insert point. */
+void MIRGraph::InlineMethod(const DexFile::CodeItem* code_item, uint32_t access_flags,
+                           InvokeType invoke_type, uint32_t class_def_idx,
+                           uint32_t method_idx, jobject class_loader, const DexFile& dex_file)
+{
+  current_code_item_ = code_item;
+  method_stack_.push_back(std::make_pair(current_method_, current_offset_));
+  current_method_ = m_units_.size();
+  current_offset_ = 0;
+  // TODO: will need to snapshot stack image and use that as the mir context identification.
+  m_units_.push_back(new DexCompilationUnit(cu_, class_loader, Runtime::Current()->GetClassLinker(),
+                     dex_file, current_code_item_, class_def_idx, method_idx, access_flags));
+  const uint16_t* code_ptr = current_code_item_->insns_;
+  const uint16_t* code_end =
+      current_code_item_->insns_ + current_code_item_->insns_size_in_code_units_;
+
+  // TODO: need to rework expansion of block list & try_block_addr when inlining activated.
+  ReallocGrowableList(cu_, &block_list_, block_list_.num_used +
+                      current_code_item_->insns_size_in_code_units_);
+  // TODO: replace with explicit resize routine.  Using automatic extension side effect for now.
+  SetBit(cu_, try_block_addr_, current_code_item_->insns_size_in_code_units_);
+  ClearBit(try_block_addr_, current_code_item_->insns_size_in_code_units_);
+
+  // If this is the first method, set up default entry and exit blocks.
+  if (current_method_ == 0) {
+    DCHECK(entry_block_ == NULL);
+    DCHECK(exit_block_ == NULL);
+    DCHECK(num_blocks_ == 0);
+    entry_block_ = NewMemBB(cu_, kEntryBlock, num_blocks_++);
+    exit_block_ = NewMemBB(cu_, kExitBlock, num_blocks_++);
+    InsertGrowableList(cu_, &block_list_, reinterpret_cast<uintptr_t>(entry_block_));
+    InsertGrowableList(cu_, &block_list_, reinterpret_cast<uintptr_t>(exit_block_));
+    // TODO: deprecate all "cu->" fields; move what's left to wherever CompilationUnit is allocated.
+    cu_->dex_file = &dex_file;
+    cu_->class_def_idx = class_def_idx;
+    cu_->method_idx = method_idx;
+    cu_->access_flags = access_flags;
+    cu_->invoke_type = invoke_type;
+    cu_->shorty = dex_file.GetMethodShorty(dex_file.GetMethodId(method_idx));
+    cu_->num_ins = current_code_item_->ins_size_;
+    cu_->num_regs = current_code_item_->registers_size_ - cu_->num_ins;
+    cu_->num_outs = current_code_item_->outs_size_;
+    cu_->num_dalvik_registers = current_code_item_->registers_size_;
+    cu_->insns = current_code_item_->insns_;
+    cu_->code_item = current_code_item_;
+  } else {
+    UNIMPLEMENTED(FATAL) << "Nested inlining not implemented.";
+    /*
+     * Will need to manage storage for ins & outs, push prevous state and update
+     * insert point.
+     */
+  }
+
+  /* Current block to record parsed instructions */
+  BasicBlock *cur_block = NewMemBB(cu_, kDalvikByteCode, num_blocks_++);
+  DCHECK_EQ(current_offset_, 0);
+  cur_block->start_offset = current_offset_;
+  InsertGrowableList(cu_, &block_list_, reinterpret_cast<uintptr_t>(cur_block));
+  /* Add first block to the fast lookup cache */
+// FIXME: block map needs association with offset/method pair rather than just offset
+  block_map_.Put(cur_block->start_offset, cur_block);
+// FIXME: this needs to insert at the insert point rather than entry block.
+  entry_block_->fall_through = cur_block;
+  InsertGrowableList(cu_, cur_block->predecessors, reinterpret_cast<uintptr_t>(entry_block_));
+
+    /* Identify code range in try blocks and set up the empty catch blocks */
+  ProcessTryCatchBlocks();
+
+  /* Set up for simple method detection */
+  int num_patterns = sizeof(special_patterns)/sizeof(special_patterns[0]);
+  bool live_pattern = (num_patterns > 0) && !(cu_->disable_opt & (1 << kMatch));
+  bool* dead_pattern =
+      static_cast<bool*>(NewMem(cu_, sizeof(bool) * num_patterns, true, kAllocMisc));
+  SpecialCaseHandler special_case = kNoHandler;
+  // FIXME - wire this up
+  (void)special_case;
+  int pattern_pos = 0;
+
+  /* Parse all instructions and put them into containing basic blocks */
+  while (code_ptr < code_end) {
+    MIR *insn = static_cast<MIR *>(NewMem(cu_, sizeof(MIR), true, kAllocMIR));
+    insn->offset = current_offset_;
+    insn->m_unit_index = current_method_;
+    int width = ParseInsn(code_ptr, &insn->dalvikInsn);
+    insn->width = width;
+    Instruction::Code opcode = insn->dalvikInsn.opcode;
+    if (opcode_count_ != NULL) {
+      opcode_count_[static_cast<int>(opcode)]++;
+    }
+
+    /* Terminate when the data section is seen */
+    if (width == 0)
+      break;
+
+    /* Possible simple method? */
+    if (live_pattern) {
+      live_pattern = false;
+      special_case = kNoHandler;
+      for (int i = 0; i < num_patterns; i++) {
+        if (!dead_pattern[i]) {
+          if (special_patterns[i].opcodes[pattern_pos] == opcode) {
+            live_pattern = true;
+            special_case = special_patterns[i].handler_code;
+          } else {
+             dead_pattern[i] = true;
+          }
+        }
+      }
+    pattern_pos++;
+    }
+
+    AppendMIR(cur_block, insn);
+
+    code_ptr += width;
+    int flags = Instruction::FlagsOf(insn->dalvikInsn.opcode);
+
+    int df_flags = oat_data_flow_attributes[insn->dalvikInsn.opcode];
+
+    if (df_flags & DF_HAS_DEFS) {
+      def_count_ += (df_flags & DF_A_WIDE) ? 2 : 1;
+    }
+
+    if (flags & Instruction::kBranch) {
+      cur_block = ProcessCanBranch(cur_block, insn, current_offset_,
+                                   width, flags, code_ptr, code_end);
+    } else if (flags & Instruction::kReturn) {
+      cur_block->terminated_by_return = true;
+      cur_block->fall_through = exit_block_;
+      InsertGrowableList(cu_, exit_block_->predecessors,
+                            reinterpret_cast<uintptr_t>(cur_block));
+      /*
+       * Terminate the current block if there are instructions
+       * afterwards.
+       */
+      if (code_ptr < code_end) {
+        /*
+         * Create a fallthrough block for real instructions
+         * (incl. NOP).
+         */
+        if (ContentIsInsn(code_ptr)) {
+            FindBlock(current_offset_ + width, /* split */ false, /* create */ true,
+                      /* immed_pred_block_p */ NULL);
+        }
+      }
+    } else if (flags & Instruction::kThrow) {
+      cur_block = ProcessCanThrow(cur_block, insn, current_offset_, width, flags, try_block_addr_,
+                                  code_ptr, code_end);
+    } else if (flags & Instruction::kSwitch) {
+      ProcessCanSwitch(cur_block, insn, current_offset_, width, flags);
+    }
+    current_offset_ += width;
+    BasicBlock *next_block = FindBlock(current_offset_, /* split */ false, /* create */
+                                      false, /* immed_pred_block_p */ NULL);
+    if (next_block) {
+      /*
+       * The next instruction could be the target of a previously parsed
+       * forward branch so a block is already created. If the current
+       * instruction is not an unconditional branch, connect them through
+       * the fall-through link.
+       */
+      DCHECK(cur_block->fall_through == NULL ||
+             cur_block->fall_through == next_block ||
+             cur_block->fall_through == exit_block_);
+
+      if ((cur_block->fall_through == NULL) && (flags & Instruction::kContinue)) {
+        cur_block->fall_through = next_block;
+        InsertGrowableList(cu_, next_block->predecessors,
+                              reinterpret_cast<uintptr_t>(cur_block));
+      }
+      cur_block = next_block;
+    }
+  }
+  if (cu_->enable_debug & (1 << kDebugDumpCFG)) {
+    DumpCFG("/sdcard/1_post_parse_cfg/", true);
+  }
+
+  if (cu_->verbose) {
+    DumpCompilationUnit(cu_);
+  }
+}
+
+void MIRGraph::ShowOpcodeStats()
+{
+  DCHECK(opcode_count_ != NULL);
+  LOG(INFO) << "Opcode Count";
+  for (int i = 0; i < kNumPackedOpcodes; i++) {
+    if (opcode_count_[i] != 0) {
+      LOG(INFO) << "-C- " << Instruction::Name(static_cast<Instruction::Code>(i))
+                << " " << opcode_count_[i];
+    }
+  }
+}
+
+// TODO: use a configurable base prefix, and adjust callers to supply pass name.
+/* Dump the CFG into a DOT graph */
+void MIRGraph::DumpCFG(const char* dir_prefix, bool all_blocks)
+{
+  FILE* file;
+  std::string fname(PrettyMethod(cu_->method_idx, *cu_->dex_file));
+  ReplaceSpecialChars(fname);
+  fname = StringPrintf("%s%s%x.dot", dir_prefix, fname.c_str(),
+                      GetEntryBlock()->fall_through->start_offset);
+  file = fopen(fname.c_str(), "w");
+  if (file == NULL) {
+    return;
+  }
+  fprintf(file, "digraph G {\n");
+
+  fprintf(file, "  rankdir=TB\n");
+
+  int num_blocks = all_blocks ? GetNumBlocks() : num_reachable_blocks_;
+  int idx;
+
+  for (idx = 0; idx < num_blocks; idx++) {
+    int block_idx = all_blocks ? idx : dfs_order_.elem_list[idx];
+    BasicBlock *bb = GetBasicBlock(block_idx);
+    if (bb == NULL) break;
+    if (bb->block_type == kDead) continue;
+    if (bb->block_type == kEntryBlock) {
+      fprintf(file, "  entry_%d [shape=Mdiamond];\n", bb->id);
+    } else if (bb->block_type == kExitBlock) {
+      fprintf(file, "  exit_%d [shape=Mdiamond];\n", bb->id);
+    } else if (bb->block_type == kDalvikByteCode) {
+      fprintf(file, "  block%04x_%d [shape=record,label = \"{ \\\n",
+              bb->start_offset, bb->id);
+      const MIR *mir;
+        fprintf(file, "    {block id %d\\l}%s\\\n", bb->id,
+                bb->first_mir_insn ? " | " : " ");
+        for (mir = bb->first_mir_insn; mir; mir = mir->next) {
+            int opcode = mir->dalvikInsn.opcode;
+            fprintf(file, "    {%04x %s %s %s\\l}%s\\\n", mir->offset,
+                    mir->ssa_rep ? GetDalvikDisassembly(cu_, mir) :
+                    (opcode < kMirOpFirst) ?  Instruction::Name(mir->dalvikInsn.opcode) :
+                    extended_mir_op_names[opcode - kMirOpFirst],
+                    (mir->optimization_flags & MIR_IGNORE_RANGE_CHECK) != 0 ? " no_rangecheck" : " ",
+                    (mir->optimization_flags & MIR_IGNORE_NULL_CHECK) != 0 ? " no_nullcheck" : " ",
+                    mir->next ? " | " : " ");
+        }
+        fprintf(file, "  }\"];\n\n");
+    } else if (bb->block_type == kExceptionHandling) {
+      char block_name[BLOCK_NAME_LEN];
+
+      GetBlockName(bb, block_name);
+      fprintf(file, "  %s [shape=invhouse];\n", block_name);
+    }
+
+    char block_name1[BLOCK_NAME_LEN], block_name2[BLOCK_NAME_LEN];
+
+    if (bb->taken) {
+      GetBlockName(bb, block_name1);
+      GetBlockName(bb->taken, block_name2);
+      fprintf(file, "  %s:s -> %s:n [style=dotted]\n",
+              block_name1, block_name2);
+    }
+    if (bb->fall_through) {
+      GetBlockName(bb, block_name1);
+      GetBlockName(bb->fall_through, block_name2);
+      fprintf(file, "  %s:s -> %s:n\n", block_name1, block_name2);
+    }
+
+    if (bb->successor_block_list.block_list_type != kNotUsed) {
+      fprintf(file, "  succ%04x_%d [shape=%s,label = \"{ \\\n",
+              bb->start_offset, bb->id,
+              (bb->successor_block_list.block_list_type == kCatch) ?
+               "Mrecord" : "record");
+      GrowableListIterator iterator;
+      GrowableListIteratorInit(&bb->successor_block_list.blocks,
+                                  &iterator);
+      SuccessorBlockInfo *successor_block_info =
+          reinterpret_cast<SuccessorBlockInfo*>(GrowableListIteratorNext(&iterator));
+
+      int succ_id = 0;
+      while (true) {
+        if (successor_block_info == NULL) break;
+
+        BasicBlock *dest_block = successor_block_info->block;
+        SuccessorBlockInfo *next_successor_block_info =
+            reinterpret_cast<SuccessorBlockInfo*>(GrowableListIteratorNext(&iterator));
+
+        fprintf(file, "    {<f%d> %04x: %04x\\l}%s\\\n",
+                succ_id++,
+                successor_block_info->key,
+                dest_block->start_offset,
+                (next_successor_block_info != NULL) ? " | " : " ");
+
+        successor_block_info = next_successor_block_info;
+      }
+      fprintf(file, "  }\"];\n\n");
+
+      GetBlockName(bb, block_name1);
+      fprintf(file, "  %s:s -> succ%04x_%d:n [style=dashed]\n",
+              block_name1, bb->start_offset, bb->id);
+
+      if (bb->successor_block_list.block_list_type == kPackedSwitch ||
+          bb->successor_block_list.block_list_type == kSparseSwitch) {
+
+        GrowableListIteratorInit(&bb->successor_block_list.blocks,
+                                    &iterator);
+
+        succ_id = 0;
+        while (true) {
+          SuccessorBlockInfo *successor_block_info =
+              reinterpret_cast<SuccessorBlockInfo*>( GrowableListIteratorNext(&iterator));
+          if (successor_block_info == NULL) break;
+
+          BasicBlock *dest_block = successor_block_info->block;
+
+          GetBlockName(dest_block, block_name2);
+          fprintf(file, "  succ%04x_%d:f%d:e -> %s:n\n", bb->start_offset,
+                  bb->id, succ_id++, block_name2);
+        }
+      }
+    }
+    fprintf(file, "\n");
+
+    if (cu_->verbose) {
+      /* Display the dominator tree */
+      GetBlockName(bb, block_name1);
+      fprintf(file, "  cfg%s [label=\"%s\", shape=none];\n",
+              block_name1, block_name1);
+      if (bb->i_dom) {
+        GetBlockName(bb->i_dom, block_name2);
+        fprintf(file, "  cfg%s:s -> cfg%s:n\n\n", block_name2, block_name1);
+      }
+    }
+  }
+  fprintf(file, "}\n");
+  fclose(file);
+}
+
+} // namespace art