Add deopt info to code object and print it

runtime/vm/deopt_instructions.cc

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include "vm/deopt_instructions.h"
+
+#include "vm/intermediate_language.h"
+#include "vm/locations.h"
+#include "vm/parser.h"
+
+namespace dart {
+
+// Deoptimization instruction moving value from optimized frame at
+// 'from_index'. 'from_index' represents the local count >= 0, first

[siva, 2012/08/04 01:21:50]

'from_index' to specified slots in the unoptimized frame.
'from_index' represents the ......

[srdjan, 2012/08/06 20:09:05]

Done.

+// argument being 0.
+class DeoptStackSlotInstr : public DeoptInstr {
+ public:
+  explicit DeoptStackSlotInstr(intptr_t from_index)
+      : stack_slot_index_(from_index) {
+    ASSERT(stack_slot_index_ >= 0);
+  }
+
+  virtual intptr_t from_index() const { return stack_slot_index_; }
+  virtual DeoptInstr::Kind kind() const { return kStackSlot; }
+
+  virtual const char* ToCString() const {
+    intptr_t len = OS::SNPrint(NULL, 0, "s%d", stack_slot_index_);
+    char* chars = reinterpret_cast<char*>(
+        Isolate::Current()->current_zone()->Allocate(len + 1));
+    OS::SNPrint(chars, len + 1, "s%d", stack_slot_index_);
+    return chars;
+  }
+
+ private:
+  const intptr_t stack_slot_index_;  // First argument is 0, always >= 0.
+
+  DISALLOW_COPY_AND_ASSIGN(DeoptStackSlotInstr);
+};
+
+
+// Deoptimization instruction creating return address using function and
+// deopt-id stored at 'object_table_index'.
+class DeoptRetAddrInstr : public DeoptInstr {
+ public:
+  explicit DeoptRetAddrInstr(intptr_t object_table_index)
+      : object_table_index_(object_table_index) {
+    ASSERT(object_table_index >= 0);
+  }
+
+  virtual intptr_t from_index() const { return object_table_index_; }
+  virtual DeoptInstr::Kind kind() const { return kReturnAddress; }
+
+  virtual const char* ToCString() const {
+    intptr_t len = OS::SNPrint(NULL, 0, "ret oti:%d", object_table_index_);
+    char* chars = reinterpret_cast<char*>(
+        Isolate::Current()->current_zone()->Allocate(len + 1));
+    OS::SNPrint(chars, len + 1, "ret oti:%d", object_table_index_);
+    return chars;
+  }
+
+ private:
+  const intptr_t object_table_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeoptRetAddrInstr);
+};
+
+
+// Deoptimization instruction moving a constant stored at 'object_table_index'.
+class DeoptConstantInstr : public DeoptInstr {
+ public:
+  explicit DeoptConstantInstr(intptr_t object_table_index)
+      : object_table_index_(object_table_index) {
+    ASSERT(object_table_index >= 0);
+  }
+
+  virtual intptr_t from_index() const { return object_table_index_; }
+  virtual DeoptInstr::Kind kind() const { return kConstant; }
+
+  virtual const char* ToCString() const {
+    intptr_t len = OS::SNPrint(NULL, 0, "const oti:%d", object_table_index_);
+    char* chars = reinterpret_cast<char*>(
+        Isolate::Current()->current_zone()->Allocate(len + 1));
+    OS::SNPrint(chars, len + 1, "const oti:%d", object_table_index_);
+    return chars;
+  }
+
+ private:
+  const intptr_t object_table_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeoptConstantInstr);
+};
+
+
+// Deoptimization instruction moving a register.
+class DeoptRegisterInstr: public DeoptInstr {
+ public:
+  explicit DeoptRegisterInstr(intptr_t reg_as_int)
+      : reg_(static_cast<Register>(reg_as_int)) {}
+
+  virtual intptr_t from_index() const { return static_cast<intptr_t>(reg_); }
+  virtual DeoptInstr::Kind kind() const { return kRegister; }
+
+  virtual const char* ToCString() const {
+    return Assembler::RegisterName(reg_);
+  }
+
+ private:
+  const Register reg_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeoptRegisterInstr);
+};
+
+
+// Deoptimization instruction creating a PC marker for the code of
+// function at 'object_table_index'.
+class DeoptPcMarkerInstr : public DeoptInstr {
+ public:
+  explicit DeoptPcMarkerInstr(intptr_t object_table_index)
+      : object_table_index_(object_table_index) {
+    ASSERT(object_table_index >= 0);
+  }
+
+  virtual intptr_t from_index() const { return object_table_index_; }
+  virtual DeoptInstr::Kind kind() const { return kPcMarker; }
+
+  virtual const char* ToCString() const {
+    intptr_t len = OS::SNPrint(NULL, 0, "pcmark oti:%d", object_table_index_);
+    char* chars = reinterpret_cast<char*>(
+        Isolate::Current()->current_zone()->Allocate(len + 1));
+    OS::SNPrint(chars, len + 1, "pcmark oti:%d", object_table_index_);
+    return chars;
+  }
+
+ private:
+  intptr_t object_table_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeoptPcMarkerInstr);
+};
+
+
+// Deoptimization instruction copying the caller saved FP from optimized frame.
+class DeoptCallerFpInstr : public DeoptInstr {
+ public:
+  DeoptCallerFpInstr() {}
+
+  virtual intptr_t from_index() const { return 0; }
+  virtual DeoptInstr::Kind kind() const { return kCallerFp; }
+
+  virtual const char* ToCString() const { return "callerfp"; }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DeoptCallerFpInstr);
+};
+
+
+// Deoptimization instruction copying the caller return address from optimzied
+// frame.
+class DeoptCallerPcInstr : public DeoptInstr {
+ public:
+  DeoptCallerPcInstr() {}
+
+  virtual intptr_t from_index() const { return 0; }
+  virtual DeoptInstr::Kind kind() const { return kCallerFp; }
+
+  virtual const char* ToCString() const { return "callerpc"; }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DeoptCallerPcInstr);
+};
+
+
+DeoptInstr* DeoptInstr::Create(intptr_t kind_as_int, intptr_t from_index) {
+  Kind kind = static_cast<Kind>(kind_as_int);
+  switch (kind) {
+    case kStackSlot:     return new DeoptStackSlotInstr(from_index);
+    case kReturnAddress: return new DeoptRetAddrInstr(from_index);
+    case kConstant:      return new DeoptConstantInstr(from_index);
+    case kRegister:      return new DeoptRegisterInstr(from_index);
+    case kPcMarker:      return new DeoptPcMarkerInstr(from_index);
+    case kCallerFp:      return new DeoptCallerFpInstr();
+    case kCallerPc:      return new DeoptCallerPcInstr();
+  }
+  UNREACHABLE();
+  return NULL;
+}
+
+
+intptr_t DeoptInfoBuilder::FindOrAddObjectInTable(const Object& obj) const {
+  for (intptr_t i = 0; i < object_table_->length(); i++) {
+    if ((*object_table_)[i]->raw() == obj.raw()) {
+      return i;
+    }
+  }
+  // Add object.
+  const intptr_t result = object_table_->length();
+  object_table_->Add(&obj);

[siva, 2012/08/04 01:21:50]

Need to assert obj is a Zone handle because you are storing away a pointer to it
in the table.

This is one of those cases where I think we should pass in a pointer to a handle
as the parameter because we are going to store it away.

Another option is to create a GrowableObjectArray object and  store the
RawObject directly in it. This GrowableObjectArray would be assigned to the code
object using MakeArray

[srdjan, 2012/08/06 20:09:05]

Discussed and switched to GrowableObjectAray.

+  return result;
+}
+
+
+// Will be neeeded for inlined functions, currently trivial.
+void DeoptInfoBuilder::AddReturnAddress(const Function& function,
+                                        intptr_t deopt_id) {
+  const intptr_t object_table_index = object_table_->length();
+  object_table_->Add(&function);
+  object_table_->Add(&Smi::ZoneHandle(Smi::New(deopt_id)));
+  instructions_.Add(new DeoptRetAddrInstr(object_table_index));
+}
+
+
+void DeoptInfoBuilder::AddPcMarker(const Function& function) {
+  // Function object was already added by AddReturnAddress, find it.
+  intptr_t from_index = FindOrAddObjectInTable(function);
+  instructions_.Add(new DeoptPcMarkerInstr(from_index));
+}
+
+
+void DeoptInfoBuilder::AddCopy(const Location& loc, const Value& value) {

[siva, 2012/08/04 01:21:50]

The "to index" is implicit and you have made a comment that these instructions
should be added in a specific order so that the "to indexes" come out correctly.
I am wondering if it makes sense to add a "to_index" parameter to this function
so that you can assert that the intended "to_index" matches the actual slot it
ends up in the array.

It is possible to make silly order mistakes and then debugging that could be a
nightmare. 

[srdjan, 2012/08/06 20:09:05]

Done.

+  DeoptInstr* deopt_instr = NULL;
+  if (loc.IsConstant()) {
+    const intptr_t object_table_index = FindOrAddObjectInTable(loc.constant());
+    deopt_instr = new DeoptConstantInstr(object_table_index);
+  } else if (loc.IsRegister()) {
+    deopt_instr = new DeoptRegisterInstr(loc.reg());
+  } else if (loc.IsStackSlot()) {
+    deopt_instr = new DeoptStackSlotInstr(loc.stack_index() + num_args_);
+  } else if (loc.IsInvalid()) {
+    ASSERT(value.IsConstant());
+    const Object& obj = value.AsConstant()->value();
+    const intptr_t object_table_index = FindOrAddObjectInTable(obj);
+    deopt_instr = new DeoptConstantInstr(object_table_index);
+  } else {
+    UNREACHABLE();
+  }
+
+  instructions_.Add(deopt_instr);
+}
+
+
+void DeoptInfoBuilder::AddCallerFp() {
+  instructions_.Add(new DeoptCallerFpInstr());
+}
+
+
+void DeoptInfoBuilder::AddCallerPc() {
+  instructions_.Add(new DeoptCallerPcInstr());
+}
+
+
+RawDeoptInfo* DeoptInfoBuilder::CreateDeoptInfo() {
+  const intptr_t len = instructions_.length();
+  const DeoptInfo& deopt_info = DeoptInfo::Handle(DeoptInfo::New(len));
+  for (intptr_t i = 0; i < len; i++) {
+    DeoptInstr* instr = instructions_[i];
+    deopt_info.SetAt(i, instr->kind(), instr->from_index());
+  }
+  return deopt_info.raw();
+}
+
+}  // namespace dart