[asm.js] Make the parser independent of the Isolate.

This removes any kind of heap access from the asm.js validator internals
and hence makes it independent of a specific Isolate. It is a precursor
towards potentially being able to run validation while streaming.

R=clemensh@chromium.org

Change-Id: Ia3770bf03bb973b56de897b27be60d7e050af2c4
Reviewed-on: https://chromium-review.googlesource.com/518188
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45628}

src/asmjs/asm-js.cc

@@ -4,8 +4,6 @@
 
 #include "src/asmjs/asm-js.h"
 
-#include "src/api-natives.h"
-#include "src/api.h"
 #include "src/asmjs/asm-names.h"
 #include "src/asmjs/asm-parser.h"
 #include "src/assert-scope.h"
@@ -17,7 +15,8 @@
 #include "src/handles.h"
 #include "src/isolate.h"
 #include "src/objects-inl.h"
-#include "src/objects.h"
+#include "src/parsing/scanner-character-streams.h"
+#include "src/parsing/scanner.h"
 
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-js.h"
@@ -192,9 +191,11 @@ MaybeHandle<FixedArray> AsmJs::CompileAsmViaWasm(CompilationInfo* info) {
 
     Zone* compile_zone = info->zone();
     Zone translate_zone(info->isolate()->allocator(), ZONE_NAME);
-    wasm::AsmJsParser parser(info->isolate(), &translate_zone, info->script(),
-                             info->literal()->start_position(),
-                             info->literal()->end_position());
+    std::unique_ptr<Utf16CharacterStream> stream(ScannerStream::For(
+        handle(String::cast(info->script()->source())),
+        info->literal()->start_position(), info->literal()->end_position()));
+    uintptr_t stack_limit = info->isolate()->stack_guard()->real_climit();
+    wasm::AsmJsParser parser(&translate_zone, stack_limit, std::move(stream));
     if (!parser.Run()) {
       DCHECK(!info->isolate()->has_pending_exception());
       ReportCompilationFailure(info->script(), parser.failure_location(),

src/asmjs/asm-parser.cc

@@ -11,9 +11,7 @@
 
 #include "src/asmjs/asm-js.h"
 #include "src/asmjs/asm-types.h"
-#include "src/objects-inl.h"
-#include "src/objects.h"
-#include "src/parsing/scanner-character-streams.h"
+#include "src/objects-inl.h"  // TODO(mstarzinger): Temporary cycle breaker.
 #include "src/parsing/scanner.h"
 #include "src/wasm/wasm-opcodes.h"
 
@@ -68,16 +66,16 @@ namespace wasm {
 
 #define TOK(name) AsmJsScanner::kToken_##name
 
-AsmJsParser::AsmJsParser(Isolate* isolate, Zone* zone, Handle<Script> script,
-                         int start, int end)
+AsmJsParser::AsmJsParser(Zone* zone, uintptr_t stack_limit,
+                         std::unique_ptr<Utf16CharacterStream> stream)
     : zone_(zone),
       module_builder_(new (zone) WasmModuleBuilder(zone)),
       return_type_(nullptr),
-      stack_limit_(isolate->stack_guard()->real_climit()),
+      stack_limit_(stack_limit),
       global_var_info_(zone),
       local_var_info_(zone),
       failed_(false),
-      failure_location_(start),
+      failure_location_(kNoSourcePosition),
       stdlib_name_(kTokenNone),
       foreign_name_(kTokenNone),
       heap_name_(kTokenNone),
@@ -89,9 +87,6 @@ AsmJsParser::AsmJsParser(Isolate* isolate, Zone* zone, Handle<Script> script,
       pending_label_(0),
       global_imports_(zone) {
   InitializeStdlibTypes();
-  Handle<String> source(String::cast(script->source()), isolate);
-  std::unique_ptr<Utf16CharacterStream> stream(
-      ScannerStream::For(source, start, end));
   scanner_.SetStream(std::move(stream));
 }
 

src/asmjs/asm-parser.h

@@ -5,8 +5,8 @@
 #ifndef V8_ASMJS_ASM_PARSER_H_
 #define V8_ASMJS_ASM_PARSER_H_
 
+#include <memory>
 #include <string>
-#include <vector>
 
 #include "src/asmjs/asm-scanner.h"
 #include "src/asmjs/asm-types.h"
@@ -15,6 +15,9 @@
 
 namespace v8 {
 namespace internal {
+
+class Utf16CharacterStream;
+
 namespace wasm {
 
 // A custom parser + validator + wasm converter for asm.js:
@@ -46,8 +49,8 @@ class AsmJsParser {
 
   typedef std::unordered_set<StandardMember, std::hash<int>> StdlibSet;
 
-  explicit AsmJsParser(Isolate* isolate, Zone* zone, Handle<Script> script,
-                       int start, int end);
+  explicit AsmJsParser(Zone* zone, uintptr_t stack_limit,
+                       std::unique_ptr<Utf16CharacterStream> stream);
   bool Run();
   const char* failure_message() const { return failure_message_; }
   int failure_location() const { return failure_location_; }

src/asmjs/asm-scanner.cc

@@ -46,6 +46,10 @@ AsmJsScanner::AsmJsScanner()
 #undef V
 }
 
+// Destructor of unique_ptr<T> requires complete declaration of T, we only want
+// to include the necessary declaration here instead of the header file.
+AsmJsScanner::~AsmJsScanner() {}
+
 void AsmJsScanner::SetStream(std::unique_ptr<Utf16CharacterStream> stream) {
   stream_ = std::move(stream);
   Next();

src/asmjs/asm-scanner.h

@@ -32,6 +32,8 @@ class V8_EXPORT_PRIVATE AsmJsScanner {
   typedef int32_t token_t;
 
   AsmJsScanner();
+  ~AsmJsScanner();
+
   // Pick the stream to parse (must be called before anything else).
   void SetStream(std::unique_ptr<Utf16CharacterStream> stream);