[wasm] Add utilities to print out WASM ast directly from the bytes.

src/flag-definitions.h

 // Copyright 2012 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.
 
 // This file defines all of the flags.  It is separated into different section,
 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
 //
 // This include does not have a guard, because it is a template-style include,
 // which can be included multiple times in different modes.  It expects to have
@@ skipping 455 matching lines @@
 DEFINE_BOOL(turbo_escape, false, "enable escape analysis")
 DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis")
 DEFINE_BOOL(turbo_instruction_scheduling, false,
             "enable instruction scheduling in TurboFan")
 
 // Flags for native WebAssembly.
 DEFINE_BOOL(expose_wasm, false, "expose WASM interface to JavaScript")
 DEFINE_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code")
 DEFINE_BOOL(trace_wasm_decode_time, false, "trace decoding time of wasm code")
 DEFINE_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code")
+DEFINE_BOOL(trace_wasm_ast, false, "dump AST after WASM decode")
 DEFINE_BOOL(wasm_break_on_decoder_error, false,
             "debug break when wasm decoder encounters an error")
 
 DEFINE_INT(typed_array_max_size_in_heap, 64,
            "threshold for in-heap typed array")
 
 // Profiler flags.
 DEFINE_INT(frame_count, 1, "number of stack frames inspected by the profiler")
 // 0x1800 fits in the immediate field of an ARM instruction.
 DEFINE_INT(interrupt_budget, 0x1800,
@@ skipping 647 matching lines @@
 #undef DEFINE_ALIAS_FLOAT
 #undef DEFINE_ALIAS_ARGS
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA