[wasm] Rework encoding of local declarations.

src/wasm/module-decoder.cc

 // 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.
 
 #include "src/macro-assembler.h"
 #include "src/objects.h"
 #include "src/v8.h"
 
 #include "src/wasm/decoder.h"
 #include "src/wasm/module-decoder.h"
@@ skipping 320 matching lines @@
       error(pc_ - 1, nullptr, "required %s section missing", name);
     } else {
       error(pc_ - 1, nullptr, "%s section already present", name);
     }
   }
 
   // Decodes a single anonymous function starting at {start_}.
   FunctionResult DecodeSingleFunction(ModuleEnv* module_env,
                                       WasmFunction* function) {
     pc_ = start_;
-    function->sig = consume_sig();                  // read signature
+    function->sig = consume_sig();               // read signature
     function->name_offset = 0;                   // ---- name
-    function->code_start_offset = off(pc_ + 8);  // ---- code start
+    function->code_start_offset = off(pc_);      // ---- code start
     function->code_end_offset = off(limit_);     // ---- code end
-    function->local_i32_count = consume_u16();      // read u16
-    function->local_i64_count = consume_u16();      // read u16
-    function->local_f32_count = consume_u16();      // read u16
-    function->local_f64_count = consume_u16();      // read u16
     function->exported = false;                  // ---- exported
     function->external = false;                  // ---- external
 
     if (ok()) VerifyFunctionBody(0, module_env, function);
 
     FunctionResult result;
     result.CopyFrom(result_);  // Copy error code and location.
     result.val = function;
     return result;
   }
@@ skipping 107 matching lines @@
 
   // Verifies the body (code) of a given function.
   void VerifyFunctionBody(uint32_t func_num, ModuleEnv* menv,
                           WasmFunction* function) {
     if (FLAG_trace_wasm_decode_time) {
       OFStream os(stdout);
       os << "Verifying WASM function " << WasmFunctionName(function, menv)
          << std::endl;
       os << std::endl;
     }
-    FunctionEnv fenv;
-    fenv.module = menv;
-    fenv.sig = function->sig;
-    fenv.local_i32_count = function->local_i32_count;
-    fenv.local_i64_count = function->local_i64_count;
-    fenv.local_f32_count = function->local_f32_count;
-    fenv.local_f64_count = function->local_f64_count;
-    fenv.SumLocals();
-
-    TreeResult result =
-        VerifyWasmCode(&fenv, start_, start_ + function->code_start_offset,
-                       start_ + function->code_end_offset);
+    FunctionBody body = {menv, function->sig, start_,
+                         start_ + function->code_start_offset,
+                         start_ + function->code_end_offset};
+    TreeResult result = VerifyWasmCode(body);
     if (result.failed()) {
       // Wrap the error message from the function decoder.
       std::ostringstream str;
       str << "in function " << WasmFunctionName(function, menv) << ": ";
       str << result;
       std::string strval = str.str();
       const char* raw = strval.c_str();
       size_t len = strlen(raw);
       char* buffer = new char[len];
       strncpy(buffer, raw, len);
@@ skipping 145 matching lines @@
   if (function_start > function_end) return FunctionError("start > end");
   if (size > kMaxFunctionSize)
     return FunctionError("size > maximum function size");
   WasmFunction* function = new WasmFunction();
   ModuleDecoder decoder(zone, function_start, function_end, kWasmOrigin);
   return decoder.DecodeSingleFunction(module_env, function);
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8