Reland: [Parse] ParseInfo owns the parsing Zone.

src/parsing/parse-info.h

Index: src/parsing/parse-info.h
diff --git a/src/parsing/parse-info.h b/src/parsing/parse-info.h
index 87052a5a7e1d053341658a12cb63f458d1e014c7..a5fd1a55d333076f4a70e86947bffcce9aea00da 100644
--- a/src/parsing/parse-info.h
+++ b/src/parsing/parse-info.h
@@ -5,6 +5,8 @@
 #ifndef V8_PARSING_PARSE_INFO_H_
 #define V8_PARSING_PARSE_INFO_H_
 
+#include <memory>
+
 #include "include/v8.h"
 #include "src/globals.h"
 #include "src/handles.h"
@@ -16,6 +18,7 @@ class Extension;
 
 namespace internal {
 
+class AccountingAllocator;
 class AstRawString;
 class AstValueFactory;
 class DeclarationScope;
@@ -29,13 +32,18 @@ class Zone;
 // A container for the inputs, configuration options, and outputs of parsing.
 class V8_EXPORT_PRIVATE ParseInfo {
  public:
-  explicit ParseInfo(Zone* zone);
-  ParseInfo(Zone* zone, Handle<Script> script);
-  ParseInfo(Zone* zone, Handle<SharedFunctionInfo> shared);
+  explicit ParseInfo(AccountingAllocator* zone_allocator);
+  ParseInfo(Handle<Script> script);
+  ParseInfo(Handle<SharedFunctionInfo> shared);
+
+  // TODO(rmcilroy): Remove once Hydrogen no longer needs this.
+  ParseInfo(Handle<SharedFunctionInfo> shared, std::shared_ptr<Zone> zone);
 
   ~ParseInfo();
 
-  Zone* zone() const { return zone_; }
+  Zone* zone() const { return zone_.get(); }

[marja, 2017/01/17 15:39:08]

Based on this CL, it's not possible to see whether the changes are correct or
not. I'd need to go and check every zone() caller to see whether any of them is
saving this pointer and using it after ParseInfo is gone. :/

[rmcilroy, 2017/01/19 12:48:29]

Given that the existing zone which was created always had the same lifetime as
the parseinfo I think this is fine, as you say all the uses of this are
temporary (and they should be since AFAIK the expectation in the style guide is
that you never stash away raw pointers you receive, only std::unique_ptr or
std::shared_ptr where you are explicilty transferring ownership).

+
+  std::shared_ptr<Zone> zone_shared() const { return zone_; }
 
 // Convenience accessor methods for flags.
 #define FLAG_ACCESSOR(flag, getter, setter)     \
@@ -224,7 +232,7 @@ class V8_EXPORT_PRIVATE ParseInfo {
   };
 
   //------------- Inputs to parsing and scope analysis -----------------------
-  Zone* zone_;
+  std::shared_ptr<Zone> zone_;
   unsigned flags_;
   ScriptCompiler::ExternalSourceStream* source_stream_;
   ScriptCompiler::StreamedSource::Encoding source_stream_encoding_;