Various improvements regarding the way we print code code comments.

* All Lithium instructions have an associated Hydrogen instruction now,
  simplifying things.

* Consistently print <Lithium instruction number,Hydrogen value id> prefixes.

* Do not print uninteresting Lithium instructions like empty gaps, jumps to the
  next instruction, etc.

* Removed special handling of HChange-like instructions, it is totally unclear
  why they had this special treatment. If we really want to print more
  information about Lithium instructions, we should do it in a totally way,
  anyway (e.g. by unifying things with the generation of hydrogen*.cfg files).

* Made deferred code and the jump table stand out a little bit more.

* Print info about special blocks like loop headers and OSR entries.

Review URL: https://codereview.chromium.org/14371005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14370 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index 618ac10..b240de7 100644 (file)
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -192,6 +192,11 @@ const char* LArithmeticT::Mnemonic() const {
 }
 
 
+bool LGoto::HasInterestingComment(LCodeGen* gen) const {
+  return !gen->IsNextEmittedBlock(block_id());
+}
+
+
 void LGoto::PrintDataTo(StringStream* stream) {
   stream->Add("B%d", block_id());
 }

diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index 6486cad..d5aef29 100644 (file)
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -282,6 +282,8 @@ class LInstruction: public ZoneObject {
   LOperand* FirstInput() { return InputAt(0); }
   LOperand* Output() { return HasResult() ? result() : NULL; }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return true; }
+
 #ifdef DEBUG
   void VerifyCall();
 #endif
@@ -381,6 +383,10 @@ class LInstructionGap: public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const {
+    return !IsRedundant();
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(InstructionGap, "gap")
 };
 
@@ -389,6 +395,7 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
   virtual void PrintDataTo(StringStream* stream);
   virtual bool IsControl() const { return true; }
@@ -436,12 +443,14 @@ class LLabel: public LGap {
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
   virtual void PrintDataTo(StringStream* stream);
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
+  bool is_osr_entry() const { return block()->is_osr_entry(); }
   Label* label() { return &label_; }
   LLabel* replacement() const { return replacement_; }
   void set_replacement(LLabel* label) { replacement_ = label; }
@@ -455,6 +464,7 @@ class LLabel: public LGap {
 
 class LParameter: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
@@ -472,6 +482,7 @@ class LCallStub: public LTemplateInstruction<1, 0, 0> {
 
 class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
@@ -2566,6 +2577,7 @@ class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry();
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 
   LOperand** SpilledRegisterArray() { return register_spills_; }

diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 5c15d49..24231c5 100644 (file)
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -264,38 +264,21 @@ bool LCodeGen::GenerateBody() {
        !is_aborted() && current_instruction_ < instructions_->length();
        current_instruction_++) {
     LInstruction* instr = instructions_->at(current_instruction_);
+
+    // Don't emit code for basic blocks with a replacement.
     if (instr->IsLabel()) {
-      LLabel* label = LLabel::cast(instr);
-      emit_instructions = !label->HasReplacement();
+      emit_instructions = !LLabel::cast(instr)->HasReplacement();
     }
+    if (!emit_instructions) continue;
 
-    if (emit_instructions) {
-      if (FLAG_code_comments) {
-        HValue* hydrogen = instr->hydrogen_value();
-        if (hydrogen != NULL) {
-          if (hydrogen->IsChange()) {
-            HValue* changed_value = HChange::cast(hydrogen)->value();
-            int use_id = 0;
-            const char* use_mnemo = "dead";
-            if (hydrogen->UseCount() >= 1) {
-              HValue* use_value = hydrogen->uses().value();
-              use_id = use_value->id();
-              use_mnemo = use_value->Mnemonic();
-            }
-            Comment(";;; @%d: %s. <of #%d %s for #%d %s>",
-                    current_instruction_, instr->Mnemonic(),
-                    changed_value->id(), changed_value->Mnemonic(),
-                    use_id, use_mnemo);
-          } else {
-            Comment(";;; @%d: %s. <#%d>", current_instruction_,
-                    instr->Mnemonic(), hydrogen->id());
-          }
-        } else {
-          Comment(";;; @%d: %s.", current_instruction_, instr->Mnemonic());
-        }
-      }
-      instr->CompileToNative(this);
+    if (FLAG_code_comments && instr->HasInterestingComment(this)) {
+      Comment(";;; <@%d,#%d> %s",
+              current_instruction_,
+              instr->hydrogen_value()->id(),
+              instr->Mnemonic());
     }
+
+    instr->CompileToNative(this);
   }
   EnsureSpaceForLazyDeopt();
   return !is_aborted();
@@ -307,11 +290,14 @@ bool LCodeGen::GenerateDeferredCode() {
   if (deferred_.length() > 0) {
     for (int i = 0; !is_aborted() && i < deferred_.length(); i++) {
       LDeferredCode* code = deferred_[i];
+      Comment(";;; <@%d,#%d> "
+              "-------------------- Deferred %s --------------------",
+              code->instruction_index(),
+              code->instr()->hydrogen_value()->id(),
+              code->instr()->Mnemonic());
       __ bind(code->entry());
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred build frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Build frame");
         ASSERT(!frame_is_built_);
         ASSERT(info()->IsStub());
         frame_is_built_ = true;
@@ -319,15 +305,11 @@ bool LCodeGen::GenerateDeferredCode() {
         __ mov(scratch0(), Operand(Smi::FromInt(StackFrame::STUB)));
         __ push(scratch0());
         __ add(fp, sp, Operand(2 * kPointerSize));
+        Comment(";;; Deferred code");
       }
-      Comment(";;; Deferred code @%d: %s.",
-              code->instruction_index(),
-              code->instr()->Mnemonic());
       code->Generate();
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred destroy frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Destroy frame");
         ASSERT(frame_is_built_);
         __ pop(ip);
         __ ldm(ia_w, sp, cp.bit() | fp.bit() | lr.bit());
@@ -358,7 +340,9 @@ bool LCodeGen::GenerateDeoptJumpTable() {
     Abort("Generated code is too large");
   }
 
-  __ RecordComment("[ Deoptimisation jump table");
+  if (deopt_jump_table_.length() > 0) {
+    Comment(";;; -------------------- Jump table --------------------");
+  }
   Label table_start;
   __ bind(&table_start);
   Label needs_frame_not_call;
@@ -419,7 +403,6 @@ bool LCodeGen::GenerateDeoptJumpTable() {
     }
     masm()->CheckConstPool(false, false);
   }
-  __ RecordComment("]");
 
   // Force constant pool emission at the end of the deopt jump table to make
   // sure that no constant pools are emitted after.
@@ -1047,10 +1030,19 @@ void LCodeGen::RecordPosition(int position) {
 }
 
 
+static const char* LabelType(LLabel* label) {
+  if (label->is_loop_header()) return " (loop header)";
+  if (label->is_osr_entry()) return " (OSR entry)";
+  return "";
+}
+
+
 void LCodeGen::DoLabel(LLabel* label) {
-  Comment(";;; -------------------- B%d%s --------------------",
+  Comment(";;; <@%d,#%d> -------------------- B%d%s --------------------",
+          current_instruction_,
+          label->hydrogen_value()->id(),
           label->block_id(),
-          label->is_loop_header() ? " (loop header)" : "");
+          LabelType(label));
   __ bind(label->label());
   current_block_ = label->block_id();
   DoGap(label);
@@ -2175,7 +2167,7 @@ void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
 }
 
 
-int LCodeGen::GetNextEmittedBlock() {
+int LCodeGen::GetNextEmittedBlock() const {
   for (int i = current_block_ + 1; i < graph()->blocks()->length(); ++i) {
     if (!chunk_->GetLabel(i)->HasReplacement()) return i;
   }
@@ -2321,9 +2313,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
 
 
 void LCodeGen::EmitGoto(int block) {
-  int destination = chunk_->LookupDestination(block);
-  if (destination != GetNextEmittedBlock()) {
-    __ jmp(chunk_->GetAssemblyLabel(destination));
+  if (!IsNextEmittedBlock(block)) {
+    __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
   }
 }
 

diff --git a/src/arm/lithium-codegen-arm.h b/src/arm/lithium-codegen-arm.h
index c104132..7df1070 100644 (file)
--- a/src/arm/lithium-codegen-arm.h
+++ b/src/arm/lithium-codegen-arm.h
@@ -80,6 +80,15 @@ class LCodeGen BASE_EMBEDDED {
   Heap* heap() const { return isolate()->heap(); }
   Zone* zone() const { return zone_; }
 
+  // TODO(svenpanne) Use this consistently.
+  int LookupDestination(int block_id) const {
+    return chunk()->LookupDestination(block_id);
+  }
+
+  bool IsNextEmittedBlock(int block_id) const {
+    return LookupDestination(block_id) == GetNextEmittedBlock();
+  }
+
   bool NeedsEagerFrame() const {
     return GetStackSlotCount() > 0 ||
         info()->is_non_deferred_calling() ||
@@ -196,12 +205,12 @@ class LCodeGen BASE_EMBEDDED {
 
   LPlatformChunk* chunk() const { return chunk_; }
   Scope* scope() const { return scope_; }
-  HGraph* graph() const { return chunk_->graph(); }
+  HGraph* graph() const { return chunk()->graph(); }
 
   Register scratch0() { return r9; }
   DwVfpRegister double_scratch0() { return kScratchDoubleReg; }
 
-  int GetNextEmittedBlock();
+  int GetNextEmittedBlock() const;
   LInstruction* GetNextInstruction();
 
   void EmitClassOfTest(Label* if_true,

diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index de62e1f..ce51ec7 100644 (file)
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -336,49 +336,28 @@ bool LCodeGen::GenerateBody() {
        !is_aborted() && current_instruction_ < instructions_->length();
        current_instruction_++) {
     LInstruction* instr = instructions_->at(current_instruction_);
+
+    // Don't emit code for basic blocks with a replacement.
     if (instr->IsLabel()) {
-      LLabel* label = LLabel::cast(instr);
-      emit_instructions = !label->HasReplacement();
+      emit_instructions = !LLabel::cast(instr)->HasReplacement();
     }
+    if (!emit_instructions) continue;
 
-    if (emit_instructions) {
-      if (FLAG_code_comments) {
-        HValue* hydrogen = instr->hydrogen_value();
-        if (hydrogen != NULL) {
-          if (hydrogen->IsChange()) {
-            HValue* changed_value = HChange::cast(hydrogen)->value();
-            int use_id = 0;
-            const char* use_mnemo = "dead";
-            if (hydrogen->UseCount() >= 1) {
-              HValue* use_value = hydrogen->uses().value();
-              use_id = use_value->id();
-              use_mnemo = use_value->Mnemonic();
-            }
-            Comment(";;; @%d: %s. <of #%d %s for #%d %s>",
-                    current_instruction_, instr->Mnemonic(),
-                    changed_value->id(), changed_value->Mnemonic(),
-                    use_id, use_mnemo);
-          } else {
-            Comment(";;; @%d: %s. <#%d>", current_instruction_,
-                    instr->Mnemonic(), hydrogen->id());
-          }
-        } else {
-          Comment(";;; @%d: %s.", current_instruction_, instr->Mnemonic());
-        }
-      }
-
-      if (!CpuFeatures::IsSupported(SSE2)) {
-        FlushX87StackIfNecessary(instr);
-      }
+    if (FLAG_code_comments && instr->HasInterestingComment(this)) {
+      Comment(";;; <@%d,#%d> %s",
+              current_instruction_,
+              instr->hydrogen_value()->id(),
+              instr->Mnemonic());
+    }
 
-      instr->CompileToNative(this);
+    if (!CpuFeatures::IsSupported(SSE2)) FlushX87StackIfNecessary(instr);
 
-      if (!CpuFeatures::IsSupported(SSE2)) {
-        ASSERT(!instr->HasDoubleRegisterResult() || x87_stack_depth_ == 1);
+    instr->CompileToNative(this);
 
-        if (FLAG_debug_code && FLAG_enable_slow_asserts) {
-          __ VerifyX87StackDepth(x87_stack_depth_);
-        }
+    if (!CpuFeatures::IsSupported(SSE2)) {
+      ASSERT(!instr->HasDoubleRegisterResult() || x87_stack_depth_ == 1);
+      if (FLAG_debug_code && FLAG_enable_slow_asserts) {
+        __ VerifyX87StackDepth(x87_stack_depth_);
       }
     }
   }
@@ -390,6 +369,9 @@ bool LCodeGen::GenerateBody() {
 bool LCodeGen::GenerateJumpTable() {
   Label needs_frame_not_call;
   Label needs_frame_is_call;
+  if (jump_table_.length() > 0) {
+    Comment(";;; -------------------- Jump table --------------------");
+  }
   for (int i = 0; i < jump_table_.length(); i++) {
     __ bind(&jump_table_[i].label);
     Address entry = jump_table_[i].address;
@@ -465,11 +447,14 @@ bool LCodeGen::GenerateDeferredCode() {
   if (deferred_.length() > 0) {
     for (int i = 0; !is_aborted() && i < deferred_.length(); i++) {
       LDeferredCode* code = deferred_[i];
+      Comment(";;; <@%d,#%d> "
+              "-------------------- Deferred %s --------------------",
+              code->instruction_index(),
+              code->instr()->hydrogen_value()->id(),
+              code->instr()->Mnemonic());
       __ bind(code->entry());
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred build frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Build frame");
         ASSERT(!frame_is_built_);
         ASSERT(info()->IsStub());
         frame_is_built_ = true;
@@ -478,15 +463,11 @@ bool LCodeGen::GenerateDeferredCode() {
         __ push(Operand(ebp, StandardFrameConstants::kContextOffset));
         __ push(Immediate(Smi::FromInt(StackFrame::STUB)));
         __ lea(ebp, Operand(esp, 2 * kPointerSize));
+        Comment(";;; Deferred code");
       }
-      Comment(";;; Deferred code @%d: %s.",
-              code->instruction_index(),
-              code->instr()->Mnemonic());
       code->Generate();
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred destroy frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Destroy frame");
         ASSERT(frame_is_built_);
         frame_is_built_ = false;
         __ mov(esp, ebp);
@@ -1125,10 +1106,19 @@ void LCodeGen::RecordPosition(int position) {
 }
 
 
+static const char* LabelType(LLabel* label) {
+  if (label->is_loop_header()) return " (loop header)";
+  if (label->is_osr_entry()) return " (OSR entry)";
+  return "";
+}
+
+
 void LCodeGen::DoLabel(LLabel* label) {
-  Comment(";;; -------------------- B%d%s --------------------",
+  Comment(";;; <@%d,#%d> -------------------- B%d%s --------------------",
+          current_instruction_,
+          label->hydrogen_value()->id(),
           label->block_id(),
-          label->is_loop_header() ? " (loop header)" : "");
+          LabelType(label));
   __ bind(label->label());
   current_block_ = label->block_id();
   DoGap(label);
@@ -2056,7 +2046,7 @@ void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
 }
 
 
-int LCodeGen::GetNextEmittedBlock() {
+int LCodeGen::GetNextEmittedBlock() const {
   for (int i = current_block_ + 1; i < graph()->blocks()->length(); ++i) {
     if (!chunk_->GetLabel(i)->HasReplacement()) return i;
   }
@@ -2203,9 +2193,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
 
 
 void LCodeGen::EmitGoto(int block) {
-  int destination = chunk_->LookupDestination(block);
-  if (destination != GetNextEmittedBlock()) {
-    __ jmp(chunk_->GetAssemblyLabel(destination));
+  if (!IsNextEmittedBlock(block)) {
+    __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
   }
 }
 

diff --git a/src/ia32/lithium-codegen-ia32.h b/src/ia32/lithium-codegen-ia32.h
index a59b368..345e945 100644 (file)
--- a/src/ia32/lithium-codegen-ia32.h
+++ b/src/ia32/lithium-codegen-ia32.h
@@ -84,6 +84,15 @@ class LCodeGen BASE_EMBEDDED {
   Heap* heap() const { return isolate()->heap(); }
   Zone* zone() const { return zone_; }
 
+  // TODO(svenpanne) Use this consistently.
+  int LookupDestination(int block_id) const {
+    return chunk()->LookupDestination(block_id);
+  }
+
+  bool IsNextEmittedBlock(int block_id) const {
+    return LookupDestination(block_id) == GetNextEmittedBlock();
+  }
+
   bool NeedsEagerFrame() const {
     return GetStackSlotCount() > 0 ||
         info()->is_non_deferred_calling() ||
@@ -189,9 +198,9 @@ class LCodeGen BASE_EMBEDDED {
 
   LPlatformChunk* chunk() const { return chunk_; }
   Scope* scope() const { return scope_; }
-  HGraph* graph() const { return chunk_->graph(); }
+  HGraph* graph() const { return chunk()->graph(); }
 
-  int GetNextEmittedBlock();
+  int GetNextEmittedBlock() const;
 
   void EmitClassOfTest(Label* if_true,
                        Label* if_false,

diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 4daf309..08ab698 100644 (file)
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -210,6 +210,11 @@ const char* LArithmeticT::Mnemonic() const {
 }
 
 
+bool LGoto::HasInterestingComment(LCodeGen* gen) const {
+  return !gen->IsNextEmittedBlock(block_id());
+}
+
+
 void LGoto::PrintDataTo(StringStream* stream) {
   stream->Add("B%d", block_id());
 }

diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 10272fd..032d17e 100644 (file)
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -278,6 +278,8 @@ class LInstruction: public ZoneObject {
   LOperand* FirstInput() { return InputAt(0); }
   LOperand* Output() { return HasResult() ? result() : NULL; }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return true; }
+
 #ifdef DEBUG
   void VerifyCall();
 #endif
@@ -378,6 +380,10 @@ class LInstructionGap: public LGap {
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
   virtual bool ClobbersDoubleRegisters() const { return false; }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const {
+    return !IsRedundant();
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(InstructionGap, "gap")
 };
 
@@ -386,6 +392,7 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
   virtual void PrintDataTo(StringStream* stream);
   virtual bool IsControl() const { return true; }
@@ -423,12 +430,14 @@ class LLabel: public LGap {
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
   virtual void PrintDataTo(StringStream* stream);
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
+  bool is_osr_entry() const { return block()->is_osr_entry(); }
   Label* label() { return &label_; }
   LLabel* replacement() const { return replacement_; }
   void set_replacement(LLabel* label) { replacement_ = label; }
@@ -442,6 +451,7 @@ class LLabel: public LGap {
 
 class LParameter: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
@@ -465,6 +475,7 @@ class LCallStub: public LTemplateInstruction<1, 1, 0> {
 
 class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
@@ -2673,6 +2684,7 @@ class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry();
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 
   LOperand** SpilledRegisterArray() { return register_spills_; }

diff --git a/src/lithium.cc b/src/lithium.cc
index b4a57f5..9f50d6c 100644 (file)
--- a/src/lithium.cc
+++ b/src/lithium.cc
@@ -341,6 +341,7 @@ void LChunk::MarkEmptyBlocks() {
 
 void LChunk::AddInstruction(LInstruction* instr, HBasicBlock* block) {
   LInstructionGap* gap = new(graph_->zone()) LInstructionGap(block);
+  gap->set_hydrogen_value(instr->hydrogen_value());
   int index = -1;
   if (instr->IsControl()) {
     instructions_.Add(gap, zone());

diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index bf227a2..9ae5132 100644 (file)
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -257,38 +257,21 @@ bool LCodeGen::GenerateBody() {
        !is_aborted() && current_instruction_ < instructions_->length();
        current_instruction_++) {
     LInstruction* instr = instructions_->at(current_instruction_);
+
+    // Don't emit code for basic blocks with a replacement.
     if (instr->IsLabel()) {
-      LLabel* label = LLabel::cast(instr);
-      emit_instructions = !label->HasReplacement();
+      emit_instructions = !LLabel::cast(instr)->HasReplacement();
     }
+    if (!emit_instructions) continue;
 
-    if (emit_instructions) {
-      if (FLAG_code_comments) {
-        HValue* hydrogen = instr->hydrogen_value();
-        if (hydrogen != NULL) {
-          if (hydrogen->IsChange()) {
-            HValue* changed_value = HChange::cast(hydrogen)->value();
-            int use_id = 0;
-            const char* use_mnemo = "dead";
-            if (hydrogen->UseCount() >= 1) {
-              HValue* use_value = hydrogen->uses().value();
-              use_id = use_value->id();
-              use_mnemo = use_value->Mnemonic();
-            }
-            Comment(";;; @%d: %s. <of #%d %s for #%d %s>",
-                    current_instruction_, instr->Mnemonic(),
-                    changed_value->id(), changed_value->Mnemonic(),
-                    use_id, use_mnemo);
-          } else {
-            Comment(";;; @%d: %s. <#%d>", current_instruction_,
-                    instr->Mnemonic(), hydrogen->id());
-          }
-        } else {
-          Comment(";;; @%d: %s.", current_instruction_, instr->Mnemonic());
-        }
-      }
-      instr->CompileToNative(this);
+    if (FLAG_code_comments && instr->HasInterestingComment(this)) {
+      Comment(";;; <@%d,#%d> %s",
+              current_instruction_,
+              instr->hydrogen_value()->id(),
+              instr->Mnemonic());
     }
+
+    instr->CompileToNative(this);
   }
   return !is_aborted();
 }
@@ -299,11 +282,14 @@ bool LCodeGen::GenerateDeferredCode() {
   if (deferred_.length() > 0) {
     for (int i = 0; !is_aborted() && i < deferred_.length(); i++) {
       LDeferredCode* code = deferred_[i];
+      Comment(";;; <@%d,#%d> "
+              "-------------------- Deferred %s --------------------",
+              code->instruction_index(),
+              code->instr()->hydrogen_value()->id(),
+              code->instr()->Mnemonic());
       __ bind(code->entry());
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred build frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Build frame");
         ASSERT(!frame_is_built_);
         ASSERT(info()->IsStub());
         frame_is_built_ = true;
@@ -311,15 +297,11 @@ bool LCodeGen::GenerateDeferredCode() {
         __ li(scratch0(), Operand(Smi::FromInt(StackFrame::STUB)));
         __ push(scratch0());
         __ Addu(fp, sp, Operand(2 * kPointerSize));
+        Comment(";;; Deferred code");
       }
-      Comment(";;; Deferred code @%d: %s.",
-              code->instruction_index(),
-              code->instr()->Mnemonic());
       code->Generate();
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred destroy frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Destroy frame");
         ASSERT(frame_is_built_);
         __ pop(at);
         __ MultiPop(cp.bit() | fp.bit() | ra.bit());
@@ -346,8 +328,10 @@ bool LCodeGen::GenerateDeoptJumpTable() {
     Abort("Generated code is too large");
   }
 
+  if (deopt_jump_table_.length() > 0) {
+    Comment(";;; -------------------- Jump table --------------------");
+  }
   Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm_);
-  __ RecordComment("[ Deoptimization jump table");
   Label table_start;
   __ bind(&table_start);
   Label needs_frame_not_call;
@@ -1023,10 +1007,19 @@ void LCodeGen::RecordPosition(int position) {
 }
 
 
+static const char* LabelType(LLabel* label) {
+  if (label->is_loop_header()) return " (loop header)";
+  if (label->is_osr_entry()) return " (OSR entry)";
+  return "";
+}
+
+
 void LCodeGen::DoLabel(LLabel* label) {
-  Comment(";;; -------------------- B%d%s --------------------",
+  Comment(";;; <@%d,#%d> -------------------- B%d%s --------------------",
+          current_instruction_,
+          label->hydrogen_value()->id(),
           label->block_id(),
-          label->is_loop_header() ? " (loop header)" : "");
+          LabelType(label));
   __ bind(label->label());
   current_block_ = label->block_id();
   DoGap(label);
@@ -1756,7 +1749,7 @@ void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
 }
 
 
-int LCodeGen::GetNextEmittedBlock() {
+int LCodeGen::GetNextEmittedBlock() const {
   for (int i = current_block_ + 1; i < graph()->blocks()->length(); ++i) {
     if (!chunk_->GetLabel(i)->HasReplacement()) return i;
   }
@@ -1915,9 +1908,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
 
 
 void LCodeGen::EmitGoto(int block) {
-  int destination = chunk_->LookupDestination(block);
-  if (destination != GetNextEmittedBlock()) {
-    __ jmp(chunk_->GetAssemblyLabel(destination));
+  if (!IsNextEmittedBlock(block)) {
+    __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
   }
 }
 

diff --git a/src/mips/lithium-codegen-mips.h b/src/mips/lithium-codegen-mips.h
index 0dbfe65..27e3061 100644 (file)
--- a/src/mips/lithium-codegen-mips.h
+++ b/src/mips/lithium-codegen-mips.h
@@ -79,6 +79,15 @@ class LCodeGen BASE_EMBEDDED {
   Heap* heap() const { return isolate()->heap(); }
   Zone* zone() const { return zone_; }
 
+  // TODO(svenpanne) Use this consistently.
+  int LookupDestination(int block_id) const {
+    return chunk()->LookupDestination(block_id);
+  }
+
+  bool IsNextEmittedBlock(int block_id) const {
+    return LookupDestination(block_id) == GetNextEmittedBlock();
+  }
+
   bool NeedsEagerFrame() const {
     return GetStackSlotCount() > 0 ||
         info()->is_non_deferred_calling() ||
@@ -190,13 +199,13 @@ class LCodeGen BASE_EMBEDDED {
 
   LPlatformChunk* chunk() const { return chunk_; }
   Scope* scope() const { return scope_; }
-  HGraph* graph() const { return chunk_->graph(); }
+  HGraph* graph() const { return chunk()->graph(); }
 
   Register scratch0() { return kLithiumScratchReg; }
   Register scratch1() { return kLithiumScratchReg2; }
   DoubleRegister double_scratch0() { return kLithiumScratchDouble; }
 
-  int GetNextEmittedBlock();
+  int GetNextEmittedBlock() const;
   LInstruction* GetNextInstruction();
 
   void EmitClassOfTest(Label* if_true,

diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 5c0b85e..fb8826b 100644 (file)
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -192,6 +192,11 @@ const char* LArithmeticT::Mnemonic() const {
 }
 
 
+bool LGoto::HasInterestingComment(LCodeGen* gen) const {
+  return !gen->IsNextEmittedBlock(block_id());
+}
+
+
 void LGoto::PrintDataTo(StringStream* stream) {
   stream->Add("B%d", block_id());
 }

diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index b0fc59a..70d0909 100644 (file)
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -279,6 +279,8 @@ class LInstruction: public ZoneObject {
   LOperand* FirstInput() { return InputAt(0); }
   LOperand* Output() { return HasResult() ? result() : NULL; }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return true; }
+
 #ifdef DEBUG
   void VerifyCall();
 #endif
@@ -378,6 +380,10 @@ class LInstructionGap: public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const {
+    return !IsRedundant();
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(InstructionGap, "gap")
 };
 
@@ -386,6 +392,7 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
   virtual void PrintDataTo(StringStream* stream);
   virtual bool IsControl() const { return true; }
@@ -433,12 +440,14 @@ class LLabel: public LGap {
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
   virtual void PrintDataTo(StringStream* stream);
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
+  bool is_osr_entry() const { return block()->is_osr_entry(); }
   Label* label() { return &label_; }
   LLabel* replacement() const { return replacement_; }
   void set_replacement(LLabel* label) { replacement_ = label; }
@@ -452,6 +461,7 @@ class LLabel: public LGap {
 
 class LParameter: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
@@ -469,6 +479,7 @@ class LCallStub: public LTemplateInstruction<1, 0, 0> {
 
 class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
@@ -2507,6 +2518,7 @@ class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry();
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 
   LOperand** SpilledRegisterArray() { return register_spills_; }

diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index fa12270..054dd60 100644 (file)
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -261,38 +261,21 @@ bool LCodeGen::GenerateBody() {
        !is_aborted() && current_instruction_ < instructions_->length();
        current_instruction_++) {
     LInstruction* instr = instructions_->at(current_instruction_);
+
+    // Don't emit code for basic blocks with a replacement.
     if (instr->IsLabel()) {
-      LLabel* label = LLabel::cast(instr);
-      emit_instructions = !label->HasReplacement();
+      emit_instructions = !LLabel::cast(instr)->HasReplacement();
     }
+    if (!emit_instructions) continue;
 
-    if (emit_instructions) {
-      if (FLAG_code_comments) {
-        HValue* hydrogen = instr->hydrogen_value();
-        if (hydrogen != NULL) {
-          if (hydrogen->IsChange()) {
-            HValue* changed_value = HChange::cast(hydrogen)->value();
-            int use_id = 0;
-            const char* use_mnemo = "dead";
-            if (hydrogen->UseCount() >= 1) {
-              HValue* use_value = hydrogen->uses().value();
-              use_id = use_value->id();
-              use_mnemo = use_value->Mnemonic();
-            }
-            Comment(";;; @%d: %s. <of #%d %s for #%d %s>",
-                    current_instruction_, instr->Mnemonic(),
-                    changed_value->id(), changed_value->Mnemonic(),
-                    use_id, use_mnemo);
-          } else {
-            Comment(";;; @%d: %s. <#%d>", current_instruction_,
-                    instr->Mnemonic(), hydrogen->id());
-          }
-        } else {
-          Comment(";;; @%d: %s.", current_instruction_, instr->Mnemonic());
-        }
-      }
-      instr->CompileToNative(this);
+    if (FLAG_code_comments && instr->HasInterestingComment(this)) {
+      Comment(";;; <@%d,#%d> %s",
+              current_instruction_,
+              instr->hydrogen_value()->id(),
+              instr->Mnemonic());
     }
+
+    instr->CompileToNative(this);
   }
   EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
   return !is_aborted();
@@ -302,6 +285,9 @@ bool LCodeGen::GenerateBody() {
 bool LCodeGen::GenerateJumpTable() {
   Label needs_frame_not_call;
   Label needs_frame_is_call;
+  if (jump_table_.length() > 0) {
+    Comment(";;; -------------------- Jump table --------------------");
+  }
   for (int i = 0; i < jump_table_.length(); i++) {
     __ bind(&jump_table_[i].label);
     Address entry = jump_table_[i].address;
@@ -368,11 +354,14 @@ bool LCodeGen::GenerateDeferredCode() {
   if (deferred_.length() > 0) {
     for (int i = 0; !is_aborted() && i < deferred_.length(); i++) {
       LDeferredCode* code = deferred_[i];
+      Comment(";;; <@%d,#%d> "
+              "-------------------- Deferred %s --------------------",
+              code->instruction_index(),
+              code->instr()->hydrogen_value()->id(),
+              code->instr()->Mnemonic());
       __ bind(code->entry());
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred build frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Build frame");
         ASSERT(!frame_is_built_);
         ASSERT(info()->IsStub());
         frame_is_built_ = true;
@@ -381,15 +370,11 @@ bool LCodeGen::GenerateDeferredCode() {
         __ push(Operand(rbp, StandardFrameConstants::kContextOffset));
         __ Push(Smi::FromInt(StackFrame::STUB));
         __ lea(rbp, Operand(rsp, 2 * kPointerSize));
+        Comment(";;; Deferred code");
       }
-      Comment(";;; Deferred code @%d: %s.",
-              code->instruction_index(),
-              code->instr()->Mnemonic());
       code->Generate();
       if (NeedsDeferredFrame()) {
-        Comment(";;; Deferred destroy frame @%d: %s.",
-                code->instruction_index(),
-                code->instr()->Mnemonic());
+        Comment(";;; Destroy frame");
         ASSERT(frame_is_built_);
         frame_is_built_ = false;
         __ movq(rsp, rbp);
@@ -925,10 +910,19 @@ void LCodeGen::RecordPosition(int position) {
 }
 
 
+static const char* LabelType(LLabel* label) {
+  if (label->is_loop_header()) return " (loop header)";
+  if (label->is_osr_entry()) return " (OSR entry)";
+  return "";
+}
+
+
 void LCodeGen::DoLabel(LLabel* label) {
-  Comment(";;; -------------------- B%d%s --------------------",
+  Comment(";;; <@%d,#%d> -------------------- B%d%s --------------------",
+          current_instruction_,
+          label->hydrogen_value()->id(),
           label->block_id(),
-          label->is_loop_header() ? " (loop header)" : "");
+          LabelType(label));
   __ bind(label->label());
   current_block_ = label->block_id();
   DoGap(label);
@@ -1822,7 +1816,7 @@ void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
 }
 
 
-int LCodeGen::GetNextEmittedBlock() {
+int LCodeGen::GetNextEmittedBlock() const {
   for (int i = current_block_ + 1; i < graph()->blocks()->length(); ++i) {
     if (!chunk_->GetLabel(i)->HasReplacement()) return i;
   }
@@ -1961,9 +1955,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
 
 
 void LCodeGen::EmitGoto(int block) {
-  int destination = chunk_->LookupDestination(block);
-  if (destination != GetNextEmittedBlock()) {
-    __ jmp(chunk_->GetAssemblyLabel(destination));
+  if (!IsNextEmittedBlock(block)) {
+    __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
   }
 }
 

diff --git a/src/x64/lithium-codegen-x64.h b/src/x64/lithium-codegen-x64.h
index a988a7a..2fe277f 100644 (file)
--- a/src/x64/lithium-codegen-x64.h
+++ b/src/x64/lithium-codegen-x64.h
@@ -80,6 +80,15 @@ class LCodeGen BASE_EMBEDDED {
   Heap* heap() const { return isolate()->heap(); }
   Zone* zone() const { return zone_; }
 
+  // TODO(svenpanne) Use this consistently.
+  int LookupDestination(int block_id) const {
+    return chunk()->LookupDestination(block_id);
+  }
+
+  bool IsNextEmittedBlock(int block_id) const {
+    return LookupDestination(block_id) == GetNextEmittedBlock();
+  }
+
   bool NeedsEagerFrame() const {
     return GetStackSlotCount() > 0 ||
         info()->is_non_deferred_calling() ||
@@ -160,9 +169,9 @@ class LCodeGen BASE_EMBEDDED {
 
   LPlatformChunk* chunk() const { return chunk_; }
   Scope* scope() const { return scope_; }
-  HGraph* graph() const { return chunk_->graph(); }
+  HGraph* graph() const { return chunk()->graph(); }
 
-  int GetNextEmittedBlock();
+  int GetNextEmittedBlock() const;
 
   void EmitClassOfTest(Label* if_true,
                        Label* if_false,

diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index e78cee4..f564e1c 100644 (file)
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -194,6 +194,11 @@ const char* LArithmeticT::Mnemonic() const {
 }
 
 
+bool LGoto::HasInterestingComment(LCodeGen* gen) const {
+  return !gen->IsNextEmittedBlock(block_id());
+}
+
+
 void LGoto::PrintDataTo(StringStream* stream) {
   stream->Add("B%d", block_id());
 }

diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index 54f117c..967b645 100644 (file)
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -280,6 +280,8 @@ class LInstruction: public ZoneObject {
   LOperand* FirstInput() { return InputAt(0); }
   LOperand* Output() { return HasResult() ? result() : NULL; }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return true; }
+
 #ifdef DEBUG
   void VerifyCall();
 #endif
@@ -381,6 +383,10 @@ class LInstructionGap: public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const {
+    return !IsRedundant();
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(InstructionGap, "gap")
 };
 
@@ -389,6 +395,7 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
   virtual void PrintDataTo(StringStream* stream);
   virtual bool IsControl() const { return true; }
@@ -436,12 +443,14 @@ class LLabel: public LGap {
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
   virtual void PrintDataTo(StringStream* stream);
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
+  bool is_osr_entry() const { return block()->is_osr_entry(); }
   Label* label() { return &label_; }
   LLabel* replacement() const { return replacement_; }
   void set_replacement(LLabel* label) { replacement_ = label; }
@@ -455,6 +464,7 @@ class LLabel: public LGap {
 
 class LParameter: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
@@ -472,6 +482,7 @@ class LCallStub: public LTemplateInstruction<1, 0, 0> {
 
 class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
@@ -2471,6 +2482,7 @@ class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry();
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 
   LOperand** SpilledRegisterArray() { return register_spills_; }