[runtime] Allocate source position table before Code.

This allocates and populates potential source position table before the
underlying {Code} objects is allocated. It essentially makes the field
holding said table immutable after allocation.

R=verwaest@chromium.org
BUG=v8:6792

Change-Id: If35462688a1b502f28ae84f73b82b5df5005735f
Reviewed-on: https://chromium-review.googlesource.com/727895Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48781}

src/code-stubs.cc

@@ -129,7 +129,7 @@ Handle<Code> PlatformCodeStub::GenerateCode() {
   masm.GetCode(isolate(), &desc);
   // Copy the generated code into a heap object.
   Handle<Code> new_object = factory->NewCode(
-      desc, Code::STUB, masm.CodeObject(), table,
+      desc, Code::STUB, masm.CodeObject(), table, MaybeHandle<ByteArray>(),
       DeoptimizationData::Empty(isolate()), NeedsImmovableCode());
   return new_object;
 }

src/compiler/code-generator.cc

@@ -290,6 +290,10 @@ Handle<Code> CodeGenerator::FinalizeCode() {
     }
   }
 
+  // Allocate the source position table.
+  Handle<ByteArray> source_positions =
+      source_position_table_builder_.ToSourcePositionTable(isolate());
+
   // Allocate deoptimization data.
   Handle<DeoptimizationData> deopt_data = GenerateDeoptimizationData();
 
@@ -300,17 +304,18 @@ Handle<Code> CodeGenerator::FinalizeCode() {
     unwinding_info_writer_.eh_frame_writer()->GetEhFrame(&desc);
   }
 
-  Handle<Code> result = isolate()->factory()->NewCode(
-      desc, info()->code_kind(), Handle<Object>(), table, deopt_data, false);
+  Handle<Code> result =
+      isolate()->factory()->NewCode(desc, info()->code_kind(), Handle<Object>(),
+                                    table, source_positions, deopt_data, false);
   isolate()->counters()->total_compiled_code_size()->Increment(
       result->instruction_size());
   result->set_is_turbofanned(true);
   result->set_stack_slots(frame()->GetTotalFrameSlotCount());
   result->set_safepoint_table_offset(safepoints()->GetCodeOffset());
-  Handle<ByteArray> source_positions =
-      source_position_table_builder_.ToSourcePositionTable(
-          isolate(), Handle<AbstractCode>::cast(result));
-  result->set_source_position_table(*source_positions);
+
+  LOG_CODE_EVENT(isolate(),
+                 CodeLinePosInfoRecordEvent(*Handle<AbstractCode>::cast(result),
+                                            *source_positions));
 
   return result;
 }

src/debug/liveedit.cc

@@ -962,8 +962,11 @@ void TranslateSourcePositionTable(Handle<BytecodeArray> code,
   }
 
   Handle<ByteArray> new_source_position_table(
-      builder.ToSourcePositionTable(isolate, Handle<AbstractCode>::cast(code)));
+      builder.ToSourcePositionTable(isolate));
   code->set_source_position_table(*new_source_position_table);
+  LOG_CODE_EVENT(isolate,
+                 CodeLinePosInfoRecordEvent(*Handle<AbstractCode>::cast(code),
+                                            *new_source_position_table));
 }
 }  // namespace
 

src/factory.cc

@@ -1783,16 +1783,20 @@ Handle<Code> Factory::NewCodeRaw(int object_size, bool immovable) {
                      Code);
 }
 
-Handle<Code> Factory::NewCode(const CodeDesc& desc, Code::Kind kind,
-                              Handle<Object> self_ref,
-                              MaybeHandle<HandlerTable> maybe_handler_table,
-                              MaybeHandle<DeoptimizationData> maybe_deopt_data,
-                              bool immovable) {
+Handle<Code> Factory::NewCode(
+    const CodeDesc& desc, Code::Kind kind, Handle<Object> self_ref,
+    MaybeHandle<HandlerTable> maybe_handler_table,
+    MaybeHandle<ByteArray> maybe_source_position_table,
+    MaybeHandle<DeoptimizationData> maybe_deopt_data, bool immovable) {
   Handle<ByteArray> reloc_info = NewByteArray(desc.reloc_size, TENURED);
 
   Handle<HandlerTable> handler_table =
       maybe_handler_table.is_null() ? HandlerTable::Empty(isolate())
                                     : maybe_handler_table.ToHandleChecked();
+  Handle<ByteArray> source_position_table =
+      maybe_source_position_table.is_null()
+          ? empty_byte_array()
+          : maybe_source_position_table.ToHandleChecked();
   Handle<DeoptimizationData> deopt_data =
       maybe_deopt_data.is_null() ? DeoptimizationData::Empty(isolate())
                                  : maybe_deopt_data.ToHandleChecked();
@@ -1831,7 +1835,7 @@ Handle<Code> Factory::NewCode(const CodeDesc& desc, Code::Kind kind,
   code->set_raw_type_feedback_info(Smi::kZero);
   code->set_next_code_link(*undefined_value(), SKIP_WRITE_BARRIER);
   code->set_handler_table(*handler_table);
-  code->set_source_position_table(*empty_byte_array(), SKIP_WRITE_BARRIER);
+  code->set_source_position_table(*source_position_table);
   code->set_constant_pool_offset(desc.instr_size - desc.constant_pool_size);
   code->set_builtin_index(-1);
   code->set_trap_handler_index(Smi::FromInt(-1));

src/factory.h

@@ -678,7 +678,9 @@ class V8_EXPORT_PRIVATE Factory final {
                        Handle<Object> self_reference,
                        MaybeHandle<HandlerTable> maybe_handler_table =
                            MaybeHandle<HandlerTable>(),
-                       MaybeHandle<DeoptimizationData> deopt_data =
+                       MaybeHandle<ByteArray> maybe_source_position_table =
+                           MaybeHandle<ByteArray>(),
+                       MaybeHandle<DeoptimizationData> maybe_deopt_data =
                            MaybeHandle<DeoptimizationData>(),
                        bool immovable = false);
 

src/interpreter/bytecode-array-writer.cc

@@ -45,14 +45,16 @@ Handle<BytecodeArray> BytecodeArrayWriter::ToBytecodeArray(
   int frame_size = register_count * kPointerSize;
   Handle<FixedArray> constant_pool =
       constant_array_builder()->ToFixedArray(isolate);
+  Handle<ByteArray> source_position_table =
+      source_position_table_builder()->ToSourcePositionTable(isolate);
   Handle<BytecodeArray> bytecode_array = isolate->factory()->NewBytecodeArray(
       bytecode_size, &bytecodes()->front(), frame_size, parameter_count,
       constant_pool);
   bytecode_array->set_handler_table(*handler_table);
-  Handle<ByteArray> source_position_table =
-      source_position_table_builder()->ToSourcePositionTable(
-          isolate, Handle<AbstractCode>::cast(bytecode_array));
   bytecode_array->set_source_position_table(*source_position_table);
+  LOG_CODE_EVENT(isolate, CodeLinePosInfoRecordEvent(
+                              *Handle<AbstractCode>::cast(bytecode_array),
+                              *source_position_table));
   return bytecode_array;
 }
 

src/interpreter/bytecode-array-writer.h

@@ -13,6 +13,7 @@
 namespace v8 {
 namespace internal {
 
+class BytecodeArray;
 class SourcePositionTableBuilder;
 
 namespace interpreter {

src/log.cc

@@ -1280,7 +1280,7 @@ void Logger::CodeMoveEvent(AbstractCode* from, Address to) {
 
 void Logger::CodeLinePosInfoRecordEvent(AbstractCode* code,
                                         ByteArray* source_position_table) {
-  if (jit_logger_) {
+  if (jit_logger_ && source_position_table->length() > 0) {
     void* jit_handler_data = jit_logger_->StartCodePosInfoEvent();
     for (SourcePositionTableIterator iter(source_position_table); !iter.done();
          iter.Advance()) {

src/source-position-table.cc

@@ -4,7 +4,6 @@
 
 #include "src/source-position-table.h"
 
-#include "src/log.h"
 #include "src/objects-inl.h"
 #include "src/objects.h"
 
@@ -138,7 +137,7 @@ void SourcePositionTableBuilder::AddEntry(const PositionTableEntry& entry) {
 }
 
 Handle<ByteArray> SourcePositionTableBuilder::ToSourcePositionTable(
-    Isolate* isolate, Handle<AbstractCode> code) {
+    Isolate* isolate) {
   if (bytes_.empty()) return isolate->factory()->empty_byte_array();
   DCHECK(!Omit());
 
@@ -147,8 +146,6 @@ Handle<ByteArray> SourcePositionTableBuilder::ToSourcePositionTable(
 
   MemCopy(table->GetDataStartAddress(), &*bytes_.begin(), bytes_.size());
 
-  LOG_CODE_EVENT(isolate, CodeLinePosInfoRecordEvent(*code, *table));
-
 #ifdef ENABLE_SLOW_DCHECKS
   // Brute force testing: Record all positions and decode
   // the entire table to verify they are identical.

src/source-position-table.h

@@ -14,8 +14,6 @@
 namespace v8 {
 namespace internal {
 
-class AbstractCode;
-class BytecodeArray;
 class ByteArray;
 template <typename T>
 class Handle;
@@ -43,8 +41,7 @@ class V8_EXPORT_PRIVATE SourcePositionTableBuilder {
   void AddPosition(size_t code_offset, SourcePosition source_position,
                    bool is_statement);
 
-  Handle<ByteArray> ToSourcePositionTable(Isolate* isolate,
-                                          Handle<AbstractCode> code);
+  Handle<ByteArray> ToSourcePositionTable(Isolate* isolate);
 
  private:
   void AddEntry(const PositionTableEntry& entry);

test/cctest/heap/test-heap.cc

@@ -5778,7 +5778,7 @@ Handle<Code> GenerateDummyImmovableCode(Isolate* isolate) {
   const bool kImmovable = true;
   Handle<Code> code = isolate->factory()->NewCode(
       desc, Code::STUB, Handle<Code>(), HandlerTable::Empty(isolate),
-      DeoptimizationData::Empty(isolate), kImmovable);
+      MaybeHandle<ByteArray>(), DeoptimizationData::Empty(isolate), kImmovable);
   CHECK(code->IsCode());
 
   return code;

test/unittests/source-position-table-unittest.cc

@@ -5,7 +5,6 @@
 #include "src/v8.h"
 
 #include "src/objects.h"
-#include "src/objects/code.h"
 #include "src/source-position-table.h"
 #include "test/unittests/test-utils.h"
 
@@ -36,8 +35,7 @@ TEST_F(SourcePositionTableTest, EncodeStatement) {
 
   // To test correctness, we rely on the assertions in ToSourcePositionTable().
   // (Also below.)
-  CHECK(!builder.ToSourcePositionTable(isolate(), Handle<AbstractCode>())
-             .is_null());
+  CHECK(!builder.ToSourcePositionTable(isolate()).is_null());
 }
 
 TEST_F(SourcePositionTableTest, EncodeStatementDuplicates) {
@@ -49,8 +47,7 @@ TEST_F(SourcePositionTableTest, EncodeStatementDuplicates) {
 
   // To test correctness, we rely on the assertions in ToSourcePositionTable().
   // (Also below.)
-  CHECK(!builder.ToSourcePositionTable(isolate(), Handle<AbstractCode>())
-             .is_null());
+  CHECK(!builder.ToSourcePositionTable(isolate()).is_null());
 }
 
 TEST_F(SourcePositionTableTest, EncodeExpression) {
@@ -58,8 +55,7 @@ TEST_F(SourcePositionTableTest, EncodeExpression) {
   for (size_t i = 0; i < arraysize(offsets); i++) {
     builder.AddPosition(offsets[i], toPos(offsets[i]), false);
   }
-  CHECK(!builder.ToSourcePositionTable(isolate(), Handle<AbstractCode>())
-             .is_null());
+  CHECK(!builder.ToSourcePositionTable(isolate()).is_null());
 }
 
 TEST_F(SourcePositionTableTest, EncodeAscending) {
@@ -88,8 +84,7 @@ TEST_F(SourcePositionTableTest, EncodeAscending) {
     }
   }
 
-  CHECK(!builder.ToSourcePositionTable(isolate(), Handle<AbstractCode>())
-             .is_null());
+  CHECK(!builder.ToSourcePositionTable(isolate()).is_null());
 }
 
 }  // namespace interpreter