[wasm] Enforce strict ordering of WASM module sections.

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 "src/wasm/wasm-opcodes.h"
 #include "src/wasm/wasm-result.h"
 
@@ skipping 10 matching lines @@
 namespace wasm {
 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 = 0x0a;
 
 // WebAssembly sections are named as strings in the binary format, but
 // internally V8 uses an enum to handle them.
 //
-// Entries have the form F(enumerator, string).
-#define FOR_EACH_WASM_SECTION_TYPE(F)          \
-  F(Memory, "memory")                          \
-  F(Signatures, "signatures")                  \
-  F(Functions, "functions")                    \
-  F(Globals, "globals")                        \
-  F(DataSegments, "data_segments")             \
-  F(FunctionTable, "function_table")           \
-  F(End, "end")                                \
-  F(StartFunction, "start_function")           \
-  F(ImportTable, "import_table")               \
-  F(ExportTable, "export_table")               \
-  F(FunctionSignatures, "function_signatures") \
-  F(FunctionBodies, "function_bodies")         \
-  F(Names, "names")
+// Entries have the form F(enumerator, order, string).
+#define FOR_EACH_WASM_SECTION_TYPE(F)             \
+  F(Signatures, 1, "signatures")                  \
+  F(ImportTable, 2, "import_table")               \
+  F(FunctionSignatures, 3, "function_signatures") \
+  F(FunctionTable, 4, "function_table")           \
+  F(Memory, 5, "memory")                          \
+  F(ExportTable, 6, "export_table")               \
+  F(StartFunction, 7, "start_function")           \
+  F(FunctionBodies, 8, "function_bodies")         \
+  F(DataSegments, 9, "data_segments")             \
+  F(Names, 10, "names")                           \
+  F(Globals, 0, "globals")                        \
+  F(Functions, 0, "functions")                    \
+  F(End, 0, "end")
 
 // Contants for the above section types: {LEB128 length, characters...}.
 #define WASM_SECTION_MEMORY 6, 'm', 'e', 'm', 'o', 'r', 'y'
 #define WASM_SECTION_SIGNATURES \
   10, 's', 'i', 'g', 'n', 'a', 't', 'u', 'r', 'e', 's'
 #define WASM_SECTION_FUNCTIONS 9, 'f', 'u', 'n', 'c', 't', 'i', 'o', 'n', 's'
 #define WASM_SECTION_GLOBALS 7, 'g', 'l', 'o', 'b', 'a', 'l', 's'
 #define WASM_SECTION_DATA_SEGMENTS \
   13, 'd', 'a', 't', 'a', '_', 's', 'e', 'g', 'm', 'e', 'n', 't', 's'
 #define WASM_SECTION_FUNCTION_TABLE \
@@ skipping 22 matching lines @@
 #define WASM_SECTION_END_SIZE ((size_t)4)
 #define WASM_SECTION_START_FUNCTION_SIZE ((size_t)15)
 #define WASM_SECTION_IMPORT_TABLE_SIZE ((size_t)13)
 #define WASM_SECTION_EXPORT_TABLE_SIZE ((size_t)13)
 #define WASM_SECTION_FUNCTION_SIGNATURES_SIZE ((size_t)20)
 #define WASM_SECTION_FUNCTION_BODIES_SIZE ((size_t)16)
 #define WASM_SECTION_NAMES_SIZE ((size_t)6)
 
 struct WasmSection {
   enum class Code : uint32_t {
-#define F(enumerator, string) enumerator,
+#define F(enumerator, order, string) enumerator,
     FOR_EACH_WASM_SECTION_TYPE(F)
 #undef F
         Max
   };
   static WasmSection::Code begin();
   static WasmSection::Code end();
   static WasmSection::Code next(WasmSection::Code code);
   static const char* getName(Code code);
+  static int getOrder(Code code);
   static size_t getNameLength(Code code);
+  static WasmSection::Code lookup(const byte* string, uint32_t length);
 };
 
 enum WasmFunctionDeclBit {
   kDeclFunctionName = 0x01,
   kDeclFunctionImport = 0x02,
   kDeclFunctionLocals = 0x04,
   kDeclFunctionExport = 0x08
 };
 
 // Constants for fixed-size elements within a module.
@@ skipping 208 matching lines @@
 
 // For testing. Decode, verify, and run the last exported function in the
 // given decoded module.
 int32_t CompileAndRunWasmModule(Isolate* isolate, WasmModule* module);
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_MODULE_H_