[wasm] Cleanup AST decoder. Remove Tree and TreeResult.

src/wasm/ast-decoder.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_AST_DECODER_H_
 #define V8_WASM_AST_DECODER_H_
 
 #include "src/signature.h"
 #include "src/wasm/decoder.h"
 #include "src/wasm/wasm-opcodes.h"
@@ skipping 204 matching lines @@
   const byte* base;   // base of the module bytes, for error reporting
   const byte* start;  // start of the function body
   const byte* end;    // end of the function body
 };
 
 static inline FunctionBody FunctionBodyForTesting(const byte* start,
                                                   const byte* end) {
   return {nullptr, nullptr, start, start, end};
 }
 
-struct Tree;
-typedef Result<Tree*> TreeResult;
+struct DecodeStruct {
+  int unused;
+};
+typedef Result<DecodeStruct*> DecodeResult;
+inline std::ostream& operator<<(std::ostream& os, const DecodeStruct& tree) {
+  return os;
+}
 
-std::ostream& operator<<(std::ostream& os, const Tree& tree);
-
-TreeResult VerifyWasmCode(base::AccountingAllocator* allocator,
-                          FunctionBody& body);
-TreeResult BuildTFGraph(base::AccountingAllocator* allocator,
-                        TFBuilder* builder, FunctionBody& body);
+DecodeResult VerifyWasmCode(base::AccountingAllocator* allocator,
+                            FunctionBody& body);
+DecodeResult BuildTFGraph(base::AccountingAllocator* allocator,
+                          TFBuilder* builder, FunctionBody& body);
 bool PrintAst(base::AccountingAllocator* allocator, const FunctionBody& body,
               std::ostream& os,
               std::vector<std::tuple<uint32_t, int, int>>* offset_table);
 
 // A simplified form of AST printing, e.g. from a debugger.
 void PrintAstForDebugging(const byte* start, const byte* end);
 
-inline TreeResult VerifyWasmCode(base::AccountingAllocator* allocator,
-                                 ModuleEnv* module, FunctionSig* sig,
-                                 const byte* start, const byte* end) {
+inline DecodeResult VerifyWasmCode(base::AccountingAllocator* allocator,
+                                   ModuleEnv* module, FunctionSig* sig,
+                                   const byte* start, const byte* end) {
   FunctionBody body = {module, sig, nullptr, start, end};
   return VerifyWasmCode(allocator, body);
 }
 
-inline TreeResult BuildTFGraph(base::AccountingAllocator* allocator,
-                               TFBuilder* builder, ModuleEnv* module,
-                               FunctionSig* sig, const byte* start,
-                               const byte* end) {
+inline DecodeResult BuildTFGraph(base::AccountingAllocator* allocator,
+                                 TFBuilder* builder, ModuleEnv* module,
+                                 FunctionSig* sig, const byte* start,
+                                 const byte* end) {
   FunctionBody body = {module, sig, nullptr, start, end};
   return BuildTFGraph(allocator, builder, body);
 }
 
 struct AstLocalDecls {
   // The size of the encoded declarations.
   uint32_t decls_encoded_size;  // size of encoded declarations
 
   // Total number of locals.
   uint32_t total_local_count;
@@ skipping 14 matching lines @@
 unsigned OpcodeLength(const byte* pc, const byte* end);
 
 // Computes the arity (number of sub-nodes) of the opcode at the given address.
 unsigned OpcodeArity(const byte* pc, const byte* end);
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_AST_DECODER_H_