Generate more stack maps during native debugging.

Generate extra stack map at the start of each java statement.
The stack maps are later translated to DWARF which allows
LLDB to set breakpoints and view local variables.

Change-Id: If00ab875513308e4a1399d1e12e0fe8934a6f0c3

13 files changed, 146 insertions, 2 deletions

diff --git a/compiler/driver/compiler_options.cc b/compiler/driver/compiler_options.cc
index 4d2d9246df..8c38cf263e 100644
--- a/compiler/driver/compiler_options.cc
+++ b/compiler/driver/compiler_options.cc
@@ -34,6 +34,7 @@ CompilerOptions::CompilerOptions()
       include_patch_information_(kDefaultIncludePatchInformation),
       top_k_profile_threshold_(kDefaultTopKProfileThreshold),
       debuggable_(false),
+      native_debuggable_(kDefaultNativeDebuggable),
       generate_debug_info_(kDefaultGenerateDebugInfo),
       implicit_null_checks_(true),
       implicit_so_checks_(true),
@@ -81,6 +82,7 @@ CompilerOptions::CompilerOptions(CompilerFilter compiler_filter,
     include_patch_information_(include_patch_information),
     top_k_profile_threshold_(top_k_profile_threshold),
     debuggable_(debuggable),
+    native_debuggable_(kDefaultNativeDebuggable),
     generate_debug_info_(generate_debug_info),
     implicit_null_checks_(implicit_null_checks),
     implicit_so_checks_(implicit_so_checks),
@@ -207,6 +209,10 @@ bool CompilerOptions::ParseCompilerOption(const StringPiece& option, UsageFn Usa
   } else if (option == "--debuggable") {
     debuggable_ = true;
     generate_debug_info_ = true;
+  } else if (option == "--native-debuggable") {
+    native_debuggable_ = true;
+    debuggable_ = true;
+    generate_debug_info_ = true;
   } else if (option.starts_with("--top-k-profile-threshold=")) {
     ParseDouble(option.data(), '=', 0.0, 100.0, &top_k_profile_threshold_, Usage);
   } else if (option == "--include-patch-information") {
diff --git a/compiler/driver/compiler_options.h b/compiler/driver/compiler_options.h
index e6acab42f2..2b047a203c 100644
--- a/compiler/driver/compiler_options.h
+++ b/compiler/driver/compiler_options.h
@@ -49,6 +49,7 @@ class CompilerOptions FINAL {
   static const size_t kDefaultTinyMethodThreshold = 20;
   static const size_t kDefaultNumDexMethodsThreshold = 900;
   static constexpr double kDefaultTopKProfileThreshold = 90.0;
+  static const bool kDefaultNativeDebuggable = false;
   static const bool kDefaultGenerateDebugInfo = kIsDebugBuild;
   static const bool kDefaultIncludePatchInformation = false;
   static const size_t kDefaultInlineDepthLimit = 3;
@@ -162,6 +163,10 @@ class CompilerOptions FINAL {
     return debuggable_;
   }
 
+  bool GetNativeDebuggable() const {
+    return native_debuggable_;
+  }
+
   bool GetGenerateDebugInfo() const {
     return generate_debug_info_;
   }
@@ -240,6 +245,7 @@ class CompilerOptions FINAL {
   // When using a profile file only the top K% of the profiled samples will be compiled.
   double top_k_profile_threshold_;
   bool debuggable_;
+  bool native_debuggable_;
   bool generate_debug_info_;
   bool implicit_null_checks_;
   bool implicit_so_checks_;
diff --git a/compiler/optimizing/builder.cc b/compiler/optimizing/builder.cc
index 1178d0fb25..4dd0d26b89 100644
--- a/compiler/optimizing/builder.cc
+++ b/compiler/optimizing/builder.cc
@@ -17,6 +17,8 @@
 #include "builder.h"
 
 #include "art_field-inl.h"
+#include "base/arena_bit_vector.h"
+#include "base/bit_vector-inl.h"
 #include "base/logging.h"
 #include "class_linker.h"
 #include "dex/verified_method.h"
@@ -458,6 +460,19 @@ bool HGraphBuilder::BuildGraph(const DexFile::CodeItem& code_item) {
     return false;
   }
 
+  // Find locations where we want to generate extra stackmaps for native debugging.
+  // This allows us to generate the info only at interesting points (for example,
+  // at start of java statement) rather than before every dex instruction.
+  const bool native_debuggable = compiler_driver_ != nullptr &&
+                                 compiler_driver_->GetCompilerOptions().GetNativeDebuggable();
+  ArenaBitVector* native_debug_info_locations;
+  if (native_debuggable) {
+    const uint32_t num_instructions = code_item.insns_size_in_code_units_;
+    native_debug_info_locations = new (arena_) ArenaBitVector (arena_, num_instructions, false);
+    native_debug_info_locations->ClearAllBits();
+    FindNativeDebugInfoLocations(code_item, native_debug_info_locations);
+  }
+
   CreateBlocksForTryCatch(code_item);
 
   InitializeParameters(code_item.ins_size_);
@@ -467,6 +482,11 @@ bool HGraphBuilder::BuildGraph(const DexFile::CodeItem& code_item) {
     // Update the current block if dex_pc starts a new block.
     MaybeUpdateCurrentBlock(dex_pc);
     const Instruction& instruction = *Instruction::At(code_ptr);
+    if (native_debuggable && native_debug_info_locations->IsBitSet(dex_pc)) {
+      if (current_block_ != nullptr) {
+        current_block_->AddInstruction(new (arena_) HNativeDebugInfo(dex_pc));
+      }
+    }
     if (!AnalyzeDexInstruction(instruction, dex_pc)) {
       return false;
     }
@@ -507,6 +527,47 @@ void HGraphBuilder::MaybeUpdateCurrentBlock(size_t dex_pc) {
   current_block_ = block;
 }
 
+void HGraphBuilder::FindNativeDebugInfoLocations(const DexFile::CodeItem& code_item,
+                                                 ArenaBitVector* locations) {
+  // The callback gets called when the line number changes.
+  // In other words, it marks the start of new java statement.
+  struct Callback {
+    static bool Position(void* ctx, const DexFile::PositionInfo& entry) {
+      static_cast<ArenaBitVector*>(ctx)->SetBit(entry.address_);
+      return false;
+    }
+  };
+  dex_file_->DecodeDebugPositionInfo(&code_item, Callback::Position, locations);
+  // Add native debug info at the start of every basic block.
+  for (uint32_t pc = 0; pc < code_item.insns_size_in_code_units_; pc++) {
+    if (FindBlockStartingAt(pc) != nullptr) {
+      locations->SetBit(pc);
+    }
+  }
+  // Instruction-specific tweaks.
+  const Instruction* const begin = Instruction::At(code_item.insns_);
+  const Instruction* const end = begin->RelativeAt(code_item.insns_size_in_code_units_);
+  for (const Instruction* inst = begin; inst < end; inst = inst->Next()) {
+    switch (inst->Opcode()) {
+      case Instruction::MOVE_EXCEPTION:
+      case Instruction::MOVE_RESULT:
+      case Instruction::MOVE_RESULT_WIDE:
+      case Instruction::MOVE_RESULT_OBJECT: {
+        // The compiler checks that there are no instructions before those.
+        // So generate HNativeDebugInfo after them instead.
+        locations->ClearBit(inst->GetDexPc(code_item.insns_));
+        const Instruction* next = inst->Next();
+        if (next < end) {
+          locations->SetBit(next->GetDexPc(code_item.insns_));
+        }
+        break;
+      }
+      default:
+        break;
+    }
+  }
+}
+
 bool HGraphBuilder::ComputeBranchTargets(const uint16_t* code_ptr,
                                          const uint16_t* code_end,
                                          size_t* number_of_branches) {
diff --git a/compiler/optimizing/builder.h b/compiler/optimizing/builder.h
index 73e85bb5e3..26bf1cbc75 100644
--- a/compiler/optimizing/builder.h
+++ b/compiler/optimizing/builder.h
@@ -112,6 +112,7 @@ class HGraphBuilder : public ValueObject {
                             const uint16_t* end,
                             size_t* number_of_branches);
   void MaybeUpdateCurrentBlock(size_t dex_pc);
+  void FindNativeDebugInfoLocations(const DexFile::CodeItem& code_item, ArenaBitVector* locations);
   HBasicBlock* FindBlockStartingAt(int32_t dex_pc) const;
   HBasicBlock* FindOrCreateBlockStartingAt(int32_t dex_pc);
 
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 07cc059983..58feb67a58 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -1618,6 +1618,14 @@ void InstructionCodeGeneratorARM::VisitDeoptimize(HDeoptimize* deoptimize) {
                         /* false_target */ nullptr);
 }
 
+void LocationsBuilderARM::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  new (GetGraph()->GetArena()) LocationSummary(info);
+}
+
+void InstructionCodeGeneratorARM::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  codegen_->RecordPcInfo(info, info->GetDexPc());
+}
+
 void LocationsBuilderARM::HandleCondition(HCondition* cond) {
   LocationSummary* locations =
       new (GetGraph()->GetArena()) LocationSummary(cond, LocationSummary::kNoCall);
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 068676da0e..b49f42b6c8 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -2949,6 +2949,14 @@ void InstructionCodeGeneratorARM64::VisitDeoptimize(HDeoptimize* deoptimize) {
                         /* false_target */ nullptr);
 }
 
+void LocationsBuilderARM64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  new (GetGraph()->GetArena()) LocationSummary(info);
+}
+
+void InstructionCodeGeneratorARM64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  codegen_->RecordPcInfo(info, info->GetDexPc());
+}
+
 void LocationsBuilderARM64::VisitInstanceFieldGet(HInstanceFieldGet* instruction) {
   HandleFieldGet(instruction);
 }
diff --git a/compiler/optimizing/code_generator_mips.cc b/compiler/optimizing/code_generator_mips.cc
index ef6b403eea..07efdee22d 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -3244,6 +3244,14 @@ void InstructionCodeGeneratorMIPS::VisitDeoptimize(HDeoptimize* deoptimize) {
                         /* false_target */ nullptr);
 }
 
+void LocationsBuilderMIPS::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  new (GetGraph()->GetArena()) LocationSummary(info);
+}
+
+void InstructionCodeGeneratorMIPS::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  codegen_->RecordPcInfo(info, info->GetDexPc());
+}
+
 void LocationsBuilderMIPS::HandleFieldGet(HInstruction* instruction, const FieldInfo& field_info) {
   Primitive::Type field_type = field_info.GetFieldType();
   bool is_wide = (field_type == Primitive::kPrimLong) || (field_type == Primitive::kPrimDouble);
diff --git a/compiler/optimizing/code_generator_mips64.cc b/compiler/optimizing/code_generator_mips64.cc
index 0f340a9a15..05834ff063 100644
--- a/compiler/optimizing/code_generator_mips64.cc
+++ b/compiler/optimizing/code_generator_mips64.cc
@@ -2745,6 +2745,14 @@ void InstructionCodeGeneratorMIPS64::VisitDeoptimize(HDeoptimize* deoptimize) {
                         /* false_target */ nullptr);
 }
 
+void LocationsBuilderMIPS64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  new (GetGraph()->GetArena()) LocationSummary(info);
+}
+
+void InstructionCodeGeneratorMIPS64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  codegen_->RecordPcInfo(info, info->GetDexPc());
+}
+
 void LocationsBuilderMIPS64::HandleFieldGet(HInstruction* instruction,
                                             const FieldInfo& field_info ATTRIBUTE_UNUSED) {
   LocationSummary* locations =
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 313610975b..fd18917842 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -1616,6 +1616,14 @@ void InstructionCodeGeneratorX86::VisitDeoptimize(HDeoptimize* deoptimize) {
                         /* false_target */ nullptr);
 }
 
+void LocationsBuilderX86::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  new (GetGraph()->GetArena()) LocationSummary(info);
+}
+
+void InstructionCodeGeneratorX86::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  codegen_->RecordPcInfo(info, info->GetDexPc());
+}
+
 void LocationsBuilderX86::VisitLocal(HLocal* local) {
   local->SetLocations(nullptr);
 }
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 0de616cbd2..ffd8c42e20 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -1600,6 +1600,14 @@ void InstructionCodeGeneratorX86_64::VisitDeoptimize(HDeoptimize* deoptimize) {
                         /* false_target */ nullptr);
 }
 
+void LocationsBuilderX86_64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  new (GetGraph()->GetArena()) LocationSummary(info);
+}
+
+void InstructionCodeGeneratorX86_64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  codegen_->RecordPcInfo(info, info->GetDexPc());
+}
+
 void LocationsBuilderX86_64::VisitLocal(HLocal* local) {
   local->SetLocations(nullptr);
 }
diff --git a/compiler/optimizing/dead_code_elimination.cc b/compiler/optimizing/dead_code_elimination.cc
index 02e5dab3d4..67ff87a759 100644
--- a/compiler/optimizing/dead_code_elimination.cc
+++ b/compiler/optimizing/dead_code_elimination.cc
@@ -165,6 +165,7 @@ void HDeadCodeElimination::RemoveDeadInstructions() {
       if (!inst->HasSideEffects()
           && !inst->CanThrow()
           && !inst->IsSuspendCheck()
+          && !inst->IsNativeDebugInfo()
           // If we added an explicit barrier then we should keep it.
           && !inst->IsMemoryBarrier()
           && !inst->IsParameterValue()
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 00820a66e7..db3e969afc 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -1066,6 +1066,7 @@ class HLoopInformationOutwardIterator : public ValueObject {
   M(MemoryBarrier, Instruction)                                         \
   M(MonitorOperation, Instruction)                                      \
   M(Mul, BinaryOperation)                                               \
+  M(NativeDebugInfo, Instruction)                                       \
   M(Neg, UnaryOperation)                                                \
   M(NewArray, Instruction)                                              \
   M(NewInstance, Instruction)                                           \
@@ -4872,6 +4873,23 @@ class HSuspendCheck : public HTemplateInstruction<0> {
   DISALLOW_COPY_AND_ASSIGN(HSuspendCheck);
 };
 
+// Pseudo-instruction which provides the native debugger with mapping information.
+// It ensures that we can generate line number and local variables at this point.
+class HNativeDebugInfo : public HTemplateInstruction<0> {
+ public:
+  explicit HNativeDebugInfo(uint32_t dex_pc)
+      : HTemplateInstruction<0>(SideEffects::None(), dex_pc) {}
+
+  bool NeedsEnvironment() const OVERRIDE {
+    return true;
+  }
+
+  DECLARE_INSTRUCTION(NativeDebugInfo);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(HNativeDebugInfo);
+};
+
 /**
  * Instruction to load a Class object.
  */
diff --git a/dex2oat/dex2oat.cc b/dex2oat/dex2oat.cc
index 6fae8e4109..21ce73c7d4 100644
--- a/dex2oat/dex2oat.cc
+++ b/dex2oat/dex2oat.cc
@@ -315,10 +315,13 @@ NO_RETURN static void Usage(const char* fmt, ...) {
   UsageError("      stripped using standard command line tools such as strip or objcopy.");
   UsageError("      (enabled by default in debug builds, disabled by default otherwise)");
   UsageError("");
-  UsageError("  --debuggable: Produce debuggable code. Implies --generate-debug-info.");
-  UsageError("");
   UsageError("  --no-generate-debug-info: Do not generate debug information for native debugging.");
   UsageError("");
+  UsageError("  --debuggable: Produce code debuggable with Java debugger. Implies -g.");
+  UsageError("");
+  UsageError("  --native-debuggable: Produce code debuggable with native debugger (like LLDB).");
+  UsageError("      Implies --debuggable.");
+  UsageError("");
   UsageError("  --runtime-arg <argument>: used to specify various arguments for the runtime,");
   UsageError("      such as initial heap size, maximum heap size, and verbose output.");
   UsageError("      Use a separate --runtime-arg switch for each argument.");