[wasm] All strings are length-prefixed and inline

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 39 matching lines @@
 
 enum WasmFunctionDeclBit {
   kDeclFunctionName = 0x01,
   kDeclFunctionImport = 0x02,
   kDeclFunctionLocals = 0x04,
   kDeclFunctionExport = 0x08
 };
 
 // Constants for fixed-size elements within a module.
 static const size_t kDeclMemorySize = 3;
-static const size_t kDeclGlobalSize = 6;
 static const size_t kDeclDataSegmentSize = 13;
 
 // Static representation of a WASM function.
 struct WasmFunction {
   FunctionSig* sig;      // signature of the function.
   uint32_t func_index;   // index into the function table.
   uint32_t sig_index;    // index into the signature table.
   uint32_t name_offset;  // offset in the module bytes of the name, if any.
+  uint32_t name_length;  // length in bytes of the name.
   uint32_t code_start_offset;    // offset in the module bytes of code start.
   uint32_t code_end_offset;      // offset in the module bytes of code end.
   uint16_t local_i32_count;      // number of i32 local variables.
   uint16_t local_i64_count;      // number of i64 local variables.
   uint16_t local_f32_count;      // number of f32 local variables.
   uint16_t local_f64_count;      // number of f64 local variables.
   bool exported;                 // true if this function is exported.
   bool external;  // true if this function is externally supplied.
 };
 
 // Static representation of an imported WASM function.
 struct WasmImport {
   FunctionSig* sig;               // signature of the function.
   uint32_t sig_index;             // index into the signature table.
   uint32_t module_name_offset;    // offset in module bytes of the module name.
+  uint32_t module_name_length;    // length in bytes of the module name.
   uint32_t function_name_offset;  // offset in module bytes of the import name.
+  uint32_t function_name_length;  // length in bytes of the import name.
 };
 
 // Static representation of an exported WASM function.
 struct WasmExport {
   uint32_t func_index;   // index into the function table.
   uint32_t name_offset;  // offset in module bytes of the name to export.
+  uint32_t name_length;  // length in bytes of the exported name.
 };
 
 // Static representation of a wasm global variable.
 struct WasmGlobal {
   uint32_t name_offset;  // offset in the module bytes of the name, if any.
+  uint32_t name_length;  // length in bytes of the global name.
   MachineType type;      // type of the global.
   uint32_t offset;       // offset from beginning of globals area.
   bool exported;         // true if this global is exported.
 };
 
 // Static representation of a wasm data segment.
 struct WasmDataSegment {
   uint32_t dest_addr;      // destination memory address of the data.
   uint32_t source_offset;  // start offset in the module bytes.
   uint32_t source_size;    // end offset in the module bytes.
@@ skipping 21 matching lines @@
   std::vector<WasmGlobal> globals;             // globals in this module.
   std::vector<FunctionSig*> signatures;        // signatures in this module.
   std::vector<WasmFunction> functions;         // functions in this module.
   std::vector<WasmDataSegment> data_segments;  // data segments in this module.
   std::vector<uint16_t> function_table;        // function table.
   std::vector<WasmImport> import_table;        // import table.
   std::vector<WasmExport> export_table;        // export table.
 
   WasmModule();
 
-  // Get a pointer to a string stored in the module bytes representing a name.
-  const char* GetName(uint32_t offset) const {
-    if (offset == 0) return "<?>";  // no name.
-    CHECK(BoundsCheck(offset, offset + 1));
-    return reinterpret_cast<const char*>(module_start + offset);
+  // Get a string stored in the module bytes representing a name.
+  WasmName GetName(uint32_t offset, uint32_t length) const {
+    if (length == 0) return {"<?>", 3};  // no name.
+    CHECK(BoundsCheck(offset, offset + length));
+    return {reinterpret_cast<const char*>(module_start + offset), length};
   }
 
-  // Get a pointer to a string stored in the module bytes representing a name.
-  const char* GetNameOrNull(uint32_t offset) const {
-    if (offset == 0) return nullptr;  // no name.
-    CHECK(BoundsCheck(offset, offset + 1));
-    return reinterpret_cast<const char*>(module_start + offset);
+  // Get a string stored in the module bytes representing a name.
+  WasmName GetNameOrNull(uint32_t offset, uint32_t length) const {
+    if (length == 0) return {NULL, 0};  // no name.
+    CHECK(BoundsCheck(offset, offset + length));
+    return {reinterpret_cast<const char*>(module_start + offset), length};
   }
 
   // Checks the given offset range is contained within the module bytes.
   bool BoundsCheck(uint32_t start, uint32_t end) const {
     size_t size = module_end - module_start;
     return start < size && end < size;
   }
 
   // Creates a new instantiation of the module in the given isolate.
   MaybeHandle<JSObject> Instantiate(Isolate* isolate, Handle<JSObject> ffi,
@@ skipping 104 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_