[wasm] Provide better stack traces for asm.js code

src/wasm/wasm-module.h

 // Copyright 2015 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.
 
 #ifndef V8_WASM_MODULE_H_
 #define V8_WASM_MODULE_H_
 
 #include <memory>
 
 #include "src/api.h"
@@ skipping 17 matching lines @@
 const size_t kMaxModuleSize = 1024 * 1024 * 1024;
 const size_t kMaxFunctionSize = 128 * 1024;
 const size_t kMaxStringSize = 256;
 const uint32_t kWasmMagic = 0x6d736100;
 const uint32_t kWasmVersion = 0x0c;
 
 const uint8_t kWasmFunctionTypeForm = 0x40;
 const uint8_t kWasmAnyFunctionTypeForm = 0x20;
 
 enum WasmSectionCode {
-  kUnknownSectionCode = 0,   // code for unknown sections
-  kTypeSectionCode = 1,      // Function signature declarations
-  kImportSectionCode = 2,    // Import declarations
-  kFunctionSectionCode = 3,  // Function declarations
-  kTableSectionCode = 4,     // Indirect function table and other tables
-  kMemorySectionCode = 5,    // Memory attributes
-  kGlobalSectionCode = 6,    // Global declarations
-  kExportSectionCode = 7,    // Exports
-  kStartSectionCode = 8,     // Start function declaration
-  kElementSectionCode = 9,   // Elements section
-  kCodeSectionCode = 10,     // Function code
-  kDataSectionCode = 11,     // Data segments
-  kNameSectionCode = 12,     // Name section (encoded as a string)
+  kUnknownSectionCode = 0,      // code for unknown sections
+  kTypeSectionCode = 1,         // Function signature declarations
+  kImportSectionCode = 2,       // Import declarations
+  kFunctionSectionCode = 3,     // Function declarations
+  kTableSectionCode = 4,        // Indirect function table and other tables
+  kMemorySectionCode = 5,       // Memory attributes
+  kGlobalSectionCode = 6,       // Global declarations
+  kExportSectionCode = 7,       // Exports
+  kStartSectionCode = 8,        // Start function declaration
+  kElementSectionCode = 9,      // Elements section
+  kCodeSectionCode = 10,        // Function code
+  kDataSectionCode = 11,        // Data segments
+  kNameSectionCode = 12,        // Name section (encoded as a string)
+  kAsmOffsetsSectionCode = 13,  // Asm.js offset table
 };
 
 inline bool IsValidSectionCode(uint8_t byte) {
   return kTypeSectionCode <= byte && byte <= kDataSectionCode;
 }
 
 const char* SectionName(WasmSectionCode code);
 
 class WasmDebugInfo;
 
@@ skipping 326 matching lines @@
 
 #define CORE_WCM_PROPERTY_TABLE(MACRO)                \
   MACRO(OBJECT, FixedArray, code_table)               \
   MACRO(OBJECT, FixedArray, imports)                  \
   MACRO(OBJECT, FixedArray, exports)                  \
   MACRO(OBJECT, FixedArray, inits)                    \
   MACRO(OBJECT, FixedArray, startup_function)         \
   MACRO(OBJECT, FixedArray, indirect_function_tables) \
   MACRO(OBJECT, SeqOneByteString, module_bytes)       \
   MACRO(OBJECT, ByteArray, function_names)            \
+  MACRO(OBJECT, Script, asm_js_script)                \
   MACRO(SMALL_NUMBER, uint32_t, min_memory_pages)     \
   MACRO(OBJECT, FixedArray, data_segments_info)       \
   MACRO(OBJECT, ByteArray, data_segments)             \
   MACRO(SMALL_NUMBER, uint32_t, globals_size)         \
   MACRO(OBJECT, JSArrayBuffer, heap)                  \
   MACRO(SMALL_NUMBER, ModuleOrigin, origin)           \
   MACRO(WEAK_LINK, WasmCompiledModule, next_instance) \
   MACRO(WEAK_LINK, WasmCompiledModule, prev_instance) \
   MACRO(WEAK_LINK, JSObject, owning_instance)         \
   MACRO(WEAK_LINK, JSObject, module_object)
@@ skipping 85 matching lines @@
                                               MaybeHandle<ByteArray> signature,
                                               Handle<JSObject> module_instance);
 
 // Check whether the given object is a wasm object.
 // This checks the number and type of internal fields, so it's not 100 percent
 // secure. If it turns out that we need more complete checks, we could add a
 // special marker as internal field, which will definitely never occur anywhere
 // else.
 bool IsWasmObject(Object* object);
 
+// Check whether the wasm module was generated from asm.js code.
+bool WasmIsAsm(Object* wasm, Isolate* isolate);
+
+// Get the script for the asm.js origin of the wasm module.
+Handle<Script> GetAsmWasmScript(Handle<JSObject> wasm);
+
+// Get the asm.js source position for the given byte offset in the given
+// function.
+int GetAsmWasmSourcePosition(Handle<JSObject> wasm, int func_index,
+                             int byte_offset);
+
 // Update memory references of code objects associated with the module
 bool UpdateWasmModuleMemory(Handle<JSObject> object, Address old_start,
                             Address new_start, uint32_t old_size,
                             uint32_t new_size);
 
 // Constructs a single function table as a FixedArray of double size,
 // populating it with function signature indices and function indices.
 Handle<FixedArray> BuildFunctionTable(Isolate* isolate, uint32_t index,
                                       const WasmModule* module);
 
 // Populates a function table by replacing function indices with handles to
 // the compiled code.
 void PopulateFunctionTable(Handle<FixedArray> table, uint32_t table_size,
                            const std::vector<Handle<Code>>* code_table);
 
 Handle<JSObject> CreateCompiledModuleObject(
     Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
     ModuleOrigin origin);
 
 V8_EXPORT_PRIVATE MaybeHandle<JSObject> CreateModuleObjectFromBytes(
     Isolate* isolate, const byte* start, const byte* end, ErrorThrower* thrower,
-    ModuleOrigin origin);
+    ModuleOrigin origin, Handle<Script> asm_js_script);

[titzer, 2016/10/11 14:51:25]

What if, instead of using a special section, we just passed the encoded
Handle<ByteArray> directly here and have the asm-wasm builder build that byte
array? That skips an extra encoding/decoding step and all the associated logic.

[Clemens Hammacher, 2016/10/11 17:04:22]

That's a very nice idea. Done. It makes things a lot easier and improves
performance.

 
 V8_EXPORT_PRIVATE bool ValidateModuleBytes(Isolate* isolate, const byte* start,
                                            const byte* end,
                                            ErrorThrower* thrower,
                                            ModuleOrigin origin);
 
 // Get the number of imported functions for a WASM instance.
 int GetNumImportedFunctions(Handle<JSObject> wasm_object);
 
 // Assumed to be called with a code object associated to a wasm module instance.
@@ skipping 12 matching lines @@
                             int instance_count);
 void ValidateModuleState(Isolate* isolate, Handle<JSObject> module_obj);
 void ValidateOrphanedInstance(Isolate* isolate, Handle<JSObject> instance);
 
 }  // namespace testing
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_MODULE_H_