Serializer: serialize internal references via object visitor.

src/serialize.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 762 matching lines @@
   if (obj->IsAllocationSite()) RelinkAllocationSite(AllocationSite::cast(obj));
 
   // Fix up strings from serialized user code.
   if (deserializing_user_code()) obj = ProcessNewObjectFromSerializedCode(obj);
 
   Object* write_back_obj = obj;
   UnalignedCopy(write_back, &write_back_obj);
 #ifdef DEBUG
   if (obj->IsCode()) {
     DCHECK(space_number == CODE_SPACE || space_number == LO_SPACE);
+#ifdef VERIFY_HEAP
+    obj->ObjectVerify();
+#endif  // VERIFY_HEAP
   } else {
     DCHECK(space_number != CODE_SPACE);
   }
-#endif
-
-  if (obj->IsCode()) {
-    // Turn internal references encoded as offsets back to absolute addresses.
-    Code* code = Code::cast(obj);
-    Address entry = code->entry();
-    int mode_mask = RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE) |
-                    RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE_ENCODED);
-    for (RelocIterator it(code, mode_mask); !it.done(); it.next()) {
-      RelocInfo* rinfo = it.rinfo();
-      intptr_t offset =
-          reinterpret_cast<intptr_t>(rinfo->target_internal_reference());
-      DCHECK(0 <= offset && offset <= code->instruction_size());
-      rinfo->set_target_internal_reference(entry + offset);
-    }
-  }
+#endif  // DEBUG
 }
 
 
 // We know the space requirements before deserialization and can
 // pre-allocate that reserved space. During deserialization, all we need
 // to do is to bump up the pointer for each space in the reserved
 // space. This is also used for fixing back references.
 // We may have to split up the pre-allocation into several chunks
 // because it would not fit onto a single page. We do not have to keep
 // track of when to move to the next chunk. An opcode will signal this.
@@ skipping 353 matching lines @@
 #undef CASE_BODY
 #undef ALL_SPACES
 
       case kSkip: {
         int size = source_.GetInt();
         current = reinterpret_cast<Object**>(
             reinterpret_cast<intptr_t>(current) + size);
         break;
       }
 
+      case kInternalReference: {
+        // Internal reference address is not encoded via skip, but by offset
+        // from code entry.
+        int pc_offset = source_.GetInt();
+        int target_offset = source_.GetInt();
+        Code* code =
+            Code::cast(HeapObject::FromAddress(current_object_address));
+        DCHECK(0 <= pc_offset && pc_offset <= code->instruction_size());
+        DCHECK(0 <= target_offset && target_offset <= code->instruction_size());
+        Address pc = code->entry() + pc_offset;
+        Address target = code->entry() + target_offset;
+        Assembler::deserialization_set_target_internal_reference_at(pc, target);
+        break;
+      }
+
       case kNativesStringResource: {
         DCHECK(!isolate_->heap()->deserialization_complete());
         int index = source_.Get();
         Vector<const char> source_vector = Natives::GetScriptSource(index);
         NativesExternalStringResource* resource =
             new NativesExternalStringResource(source_vector.start(),
                                               source_vector.length());
         Object* resource_obj = reinterpret_cast<Object*>(resource);
         UnalignedCopy(current++, &resource_obj);
         break;
@@ skipping 667 matching lines @@
                            kCanReturnSkipInsteadOfSkipping);
   HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
   sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
   sink_->PutInt(skip, "SkipB4ExternalRef");
   Address target = rinfo->target_external_reference();
   sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
   bytes_processed_so_far_ += rinfo->target_address_size();
 }
 
 
+void Serializer::ObjectSerializer::VisitInternalReference(RelocInfo* rinfo) {
+  // We can only reference to internal references of code that has been output.
+  DCHECK(is_code_object_ && code_has_been_output_);
+  // We do not use skip from last patched pc to find the pc to patch, since
+  // target_address_address may not return addresses in ascending order when
+  // used for internal references. External references may be stored at the
+  // end of the code in the constant pool, whereas internal references are
+  // inline. That would cause the skip to be negative. Instead, we store the
+  // offset from code entry.
+  Address entry = Code::cast(object_)->entry();
+  intptr_t pc_offset = rinfo->target_internal_reference_address() - entry;
+  intptr_t target_offset = rinfo->target_internal_reference() - entry;
+  DCHECK(0 <= pc_offset &&
+         pc_offset <= Code::cast(object_)->instruction_size());
+  DCHECK(0 <= target_offset &&
+         target_offset <= Code::cast(object_)->instruction_size());
+  sink_->Put(kInternalReference, "InternalRef");
+  sink_->PutInt(static_cast<uintptr_t>(pc_offset), "internal ref address");
+  sink_->PutInt(static_cast<uintptr_t>(target_offset), "internal ref value");
+}
+
+
 void Serializer::ObjectSerializer::VisitRuntimeEntry(RelocInfo* rinfo) {
   int skip = OutputRawData(rinfo->target_address_address(),
                            kCanReturnSkipInsteadOfSkipping);
   HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
   sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
   sink_->PutInt(skip, "SkipB4ExternalRef");
   Address target = rinfo->target_address();
   sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
   bytes_processed_so_far_ += rinfo->target_address_size();
 }
@@ skipping 55 matching lines @@
 }
 
 
 Address Serializer::ObjectSerializer::PrepareCode() {
   // To make snapshots reproducible, we make a copy of the code object
   // and wipe all pointers in the copy, which we then serialize.
   Code* original = Code::cast(object_);
   Code* code = serializer_->CopyCode(original);
   // Code age headers are not serializable.
   code->MakeYoung(serializer_->isolate());
-  Address entry = original->entry();
   int mode_mask = RelocInfo::kCodeTargetMask |
                   RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
                   RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
                   RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY) |
                   RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE) |
                   RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE_ENCODED);
   for (RelocIterator it(code, mode_mask); !it.done(); it.next()) {
     RelocInfo* rinfo = it.rinfo();
-    RelocInfo::Mode rmode = rinfo->rmode();
-    if (RelocInfo::IsInternalReference(rmode) ||
-        RelocInfo::IsInternalReferenceEncoded(rmode)) {
-      // Convert internal references to relative offsets.
-      Address target = rinfo->target_internal_reference();
-      intptr_t offset = target - entry;
-      DCHECK(0 <= offset && offset <= original->instruction_size());
-      rinfo->set_target_internal_reference(reinterpret_cast<Address>(offset));
-    } else if (!(FLAG_enable_ool_constant_pool && rinfo->IsInConstantPool())) {
+    if (!(FLAG_enable_ool_constant_pool && rinfo->IsInConstantPool())) {
       rinfo->WipeOut();
     }
   }
   // We need to wipe out the header fields *after* wiping out the
   // relocations, because some of these fields are needed for the latter.
   code->WipeOutHeader();
   return code->address();
 }
 
 
 int Serializer::ObjectSerializer::OutputRawData(
     Address up_to, Serializer::ObjectSerializer::ReturnSkip return_skip) {
   Address object_start = object_->address();
   int base = bytes_processed_so_far_;
   int up_to_offset = static_cast<int>(up_to - object_start);
   int to_skip = up_to_offset - bytes_processed_so_far_;
   int bytes_to_output = to_skip;
   bytes_processed_so_far_ += to_skip;
   // This assert will fail if the reloc info gives us the target_address_address
   // locations in a non-ascending order.  Luckily that doesn't happen.
   DCHECK(to_skip >= 0);
   bool outputting_code = false;
-  if (to_skip != 0 && code_object_ && !code_has_been_output_) {
+  if (to_skip != 0 && is_code_object_ && !code_has_been_output_) {
     // Output the code all at once and fix later.
     bytes_to_output = object_->Size() + to_skip - bytes_processed_so_far_;
     outputting_code = true;
     code_has_been_output_ = true;
   }
-  if (bytes_to_output != 0 &&
-      (!code_object_ || outputting_code)) {
+  if (bytes_to_output != 0 && (!is_code_object_ || outputting_code)) {
 #define RAW_CASE(index)                                                        \
     if (!outputting_code && bytes_to_output == index * kPointerSize &&         \
         index * kPointerSize == to_skip) {                                     \
       sink_->PutSection(kRawData + index, "RawDataFixed");                     \
       to_skip = 0;  /* This insn already skips. */                             \
     } else  /* NOLINT */
     COMMON_RAW_LENGTHS(RAW_CASE)
 #undef RAW_CASE
     {  /* NOLINT */
       // We always end up here if we are outputting the code of a code object.
       sink_->Put(kRawData, "RawData");
       sink_->PutInt(bytes_to_output, "length");
     }
 
-    if (code_object_) object_start = PrepareCode();
+    if (is_code_object_) object_start = PrepareCode();
 
-    const char* description = code_object_ ? "Code" : "Byte";
+    const char* description = is_code_object_ ? "Code" : "Byte";
 #ifdef MEMORY_SANITIZER
     // Object sizes are usually rounded up with uninitialized padding space.
     MSAN_MEMORY_IS_INITIALIZED(object_start + base, bytes_to_output);
 #endif  // MEMORY_SANITIZER
     sink_->PutRaw(object_start + base, bytes_to_output, description);
   }
   if (to_skip != 0 && return_skip == kIgnoringReturn) {
     sink_->Put(kSkip, "Skip");
     sink_->PutInt(to_skip, "SkipDistance");
     to_skip = 0;
@@ skipping 303 matching lines @@
   if (isolate->logger()->is_logging_code_events() ||
       isolate->cpu_profiler()->is_profiling()) {
     String* name = isolate->heap()->empty_string();
     if (result->script()->IsScript()) {
       Script* script = Script::cast(result->script());
       if (script->name()->IsString()) name = String::cast(script->name());
     }
     isolate->logger()->CodeCreateEvent(Logger::SCRIPT_TAG, result->code(),
                                        *result, NULL, name);
   }
-
   return scope.CloseAndEscape(result);
 }
 
 
 void SerializedData::AllocateData(int size) {
   DCHECK(!owns_data_);
   data_ = NewArray<byte>(size);
   size_ = size;
   owns_data_ = true;
   DCHECK(IsAligned(reinterpret_cast<intptr_t>(data_), kPointerAlignment));
@@ skipping 211 matching lines @@
   DisallowHeapAllocation no_gc;
   SerializedCodeData* scd = new SerializedCodeData(cached_data);
   SanityCheckResult r = scd->SanityCheck(isolate, source);
   if (r == CHECK_SUCCESS) return scd;
   cached_data->Reject();
   source->GetIsolate()->counters()->code_cache_reject_reason()->AddSample(r);
   delete scd;
   return NULL;
 }
 } }  // namespace v8::internal