[wasm] Introduce the --print-wasm-code flag to print wasm code.

R=titzer@chromium.org

Review-Url: https://codereview.chromium.org/2663433003
Cr-Commit-Position: refs/heads/master@{#43129}

src/codegen.cc

@@ -237,7 +237,8 @@ void CodeGenerator::PrintCode(Handle<Code> code, CompilationInfo* info) {
           ? FLAG_print_builtin_code
           : (FLAG_print_code || (info->IsStub() && FLAG_print_code_stubs) ||
              (info->IsOptimizing() && FLAG_print_opt_code &&
-              info->shared_info()->PassesFilter(FLAG_print_opt_code_filter)));
+              info->shared_info()->PassesFilter(FLAG_print_opt_code_filter)) ||
+             (info->IsWasm() && FLAG_print_wasm_code));
   if (print_code) {
     std::unique_ptr<char[]> debug_name = info->GetDebugName();
     CodeTracer::Scope tracing_scope(info->isolate()->GetCodeTracer());

src/compilation-info.h

@@ -210,6 +210,7 @@ class V8_EXPORT_PRIVATE CompilationInfo final {
   // Accessors for the different compilation modes.
   bool IsOptimizing() const { return mode_ == OPTIMIZE; }
   bool IsStub() const { return mode_ == STUB; }
+  bool IsWasm() const { return output_code_kind() == Code::WASM_FUNCTION; }
   void SetOptimizing();
   void SetOptimizingForOsr(BailoutId osr_ast_id, JavaScriptFrame* osr_frame) {
     SetOptimizing();

src/flag-definitions.h

@@ -573,6 +573,8 @@ DEFINE_BOOL(wasm_trap_if, true,
             "enable the use of the trap_if operator for traps")
 DEFINE_BOOL(wasm_code_fuzzer_gen_test, false,
             "Generate a test case when running the wasm-code fuzzer")
+DEFINE_BOOL(print_wasm_code, false, "Print WebAssembly code")
+
 // 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.