Uniform and precise source positions for inlining

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 921bb8f7bcac572114d18bf7aeb1e55780cbdf15..50ebc2dff63f99c6d1d4081c836449c801ed5922 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -13370,8 +13370,12 @@ void Script::InitLineEnds(Handle<Script> script) {
 #define SMI_VALUE(x) (Smi::cast(x)->value())
 bool Script::GetPositionInfo(int position, PositionInfo* info,

[Michael Starzinger, 2016/11/03 12:41:44]

Note that it inherently unsafe to transition from unhandlified code to
handlified code. Please add a TODO to this method that the entire method and all
call-sites should be handlified.

Especially new call sites in the deoptimizer for tracing are highly problematic.
Because then we potentially trigger crashes in the deoptimizer due to stale
pointer only when tracing is enabled. That would be very unfortunate while
debugging the deoptimizer.

I am borderline OK with landing this as it is, since the problem already existed
before. But I don't think it is wise to ignore this problem for much longer and
would like to follow-up after this CL landed.

                              OffsetFlag offset_flag) {
-  Handle<Script> script(this);
-  InitLineEnds(script);
+  Script* script = this;
+  if (script->line_ends()->IsUndefined(GetIsolate())) {
+    Handle<Script> script_handle(script);
+    InitLineEnds(script_handle);
+    script = *script_handle;
+  }
 
   DisallowHeapAllocation no_allocation;
 
@@ -13420,7 +13424,7 @@ bool Script::GetPositionInfo(int position, PositionInfo* info,
   info->line_end = SMI_VALUE(ends->get(info->line));
   if (info->line_end > 0) {
     DCHECK(script->source()->IsString());
-    Handle<String> src(String::cast(script->source()));
+    String* src = String::cast(script->source());
     if (src->length() >= info->line_end &&
         src->Get(info->line_end - 1) == '\r') {
       info->line_end--;
@@ -14239,7 +14243,7 @@ int AbstractCode::SourcePosition(int offset) {
   for (SourcePositionTableIterator iterator(source_position_table());
        !iterator.done() && iterator.code_offset() <= offset;
        iterator.Advance()) {
-    position = iterator.source_position();
+    position = iterator.source_position().ScriptOffset();
   }
   return position;
 }
@@ -14252,7 +14256,7 @@ int AbstractCode::SourceStatementPosition(int offset) {
   for (SourcePositionTableIterator it(source_position_table()); !it.done();
        it.Advance()) {
     if (it.is_statement()) {
-      int p = it.source_position();
+      int p = it.source_position().ScriptOffset();
       if (statement_position < p && p <= position) {
         statement_position = p;
       }
@@ -14472,12 +14476,13 @@ void Code::PrintDeoptLocation(FILE* out, Address pc) {
   class SourcePosition pos = info.position;
   if (info.deopt_reason != DeoptimizeReason::kNoReason || !pos.IsUnknown()) {
     if (FLAG_hydrogen_track_positions) {
-      PrintF(out, "            ;;; deoptimize at %d_%d: %s\n",
-             pos.inlining_id(), pos.position(),
-             DeoptimizeReasonToString(info.deopt_reason));
+      PrintF(out, "            ;;; deoptimize at %d_%d: %s\n", pos.InliningId(),
+             pos.ScriptOffset(), DeoptimizeReasonToString(info.deopt_reason));
     } else {
-      PrintF(out, "            ;;; deoptimize at %d: %s\n", pos.raw(),
-             DeoptimizeReasonToString(info.deopt_reason));
+      PrintF(out, "            ;;; deoptimize at ");
+      OFStream outstr(out);
+      pos.Print(outstr, this);
+      PrintF(out, ", %s\n", DeoptimizeReasonToString(info.deopt_reason));
     }
   }
 }
@@ -14916,8 +14921,8 @@ void Code::Disassemble(const char* name, std::ostream& os) {  // NOLINT
     os << "Source positions:\n pc offset  position\n";
     for (; !it.done(); it.Advance()) {
       os << std::setw(10) << it.code_offset() << std::setw(10)
-         << it.source_position() << (it.is_statement() ? "  statement" : "")
-         << "\n";
+         << it.source_position().ScriptOffset()
+         << (it.is_statement() ? "  statement" : "") << "\n";
     }
     os << "\n";
   }
@@ -15019,7 +15024,7 @@ void BytecodeArray::Disassemble(std::ostream& os) {
   while (!iterator.done()) {
     if (!source_positions.done() &&
         iterator.current_offset() == source_positions.code_offset()) {
-      os << std::setw(5) << source_positions.source_position();
+      os << std::setw(5) << source_positions.source_position().ScriptOffset();
       os << (source_positions.is_statement() ? " S> " : " E> ");
       source_positions.Advance();
     } else {