[wasm] Print stub call target with --print-wasm-code.

R=titzer@chromium.org

Change-Id: Id2766ee8d69ebd1a747374f1be71788c77a41d70
Reviewed-on: https://chromium-review.googlesource.com/1254128Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56318}

src/disassembler.cc

@@ -142,8 +142,8 @@ static const int kRelocInfoPosition = 57;
 
 static void PrintRelocInfo(StringBuilder* out, Isolate* isolate,
                            const ExternalReferenceEncoder* ref_encoder,
-                           std::ostream* os, RelocInfo* relocinfo,
-                           bool first_reloc_info = true) {
+                           std::ostream* os, CodeReference host,
+                           RelocInfo* relocinfo, bool first_reloc_info = true) {
   // Indent the printing of the reloc info.
   if (first_reloc_info) {
     // The first reloc info is printed after the disassembled instruction.
@@ -199,6 +199,10 @@ static void PrintRelocInfo(StringBuilder* out, Isolate* isolate,
     } else {
       out->AddFormatted(" %s", Code::Kind2String(kind));
     }
+  } else if (RelocInfo::IsWasmStubCall(rmode)) {
+    wasm::WasmCode* code = host.as_wasm_code()->native_module()->Lookup(
+        relocinfo->wasm_stub_call_address());
+    out->AddFormatted("    ;; wasm stub: %s", code->GetRuntimeStubName());
   } else if (RelocInfo::IsRuntimeEntry(rmode) && isolate &&
              isolate->deoptimizer_data() != nullptr) {
     // A runtime entry relocinfo might be a deoptimization bailout.
@@ -313,7 +317,7 @@ static int DecodeIt(Isolate* isolate, ExternalReferenceEncoder* ref_encoder,
       RelocInfo relocinfo(pcs[i], rmodes[i], datas[i], nullptr, constant_pool);
 
       bool first_reloc_info = (i == 0);
-      PrintRelocInfo(&out, isolate, ref_encoder, os, &relocinfo,
+      PrintRelocInfo(&out, isolate, ref_encoder, os, code, &relocinfo,
                      first_reloc_info);
     }
 
@@ -331,7 +335,8 @@ static int DecodeIt(Isolate* isolate, ExternalReferenceEncoder* ref_encoder,
           if (reloc_it.rinfo()->IsInConstantPool() &&
               (reloc_it.rinfo()->constant_pool_entry_address() ==
                constant_pool_entry_address)) {
-            PrintRelocInfo(&out, isolate, ref_encoder, os, reloc_it.rinfo());
+            PrintRelocInfo(&out, isolate, ref_encoder, os, code,
+                           reloc_it.rinfo());
             break;
           }
           reloc_it.next();

src/wasm/wasm-code-manager.cc

@@ -179,6 +179,19 @@ void WasmCode::LogCode(Isolate* isolate) const {
   }
 }
 
+const char* WasmCode::GetRuntimeStubName() const {
+  DCHECK_EQ(WasmCode::kRuntimeStub, kind());
+#define RETURN_NAME(Name)                                               \
+  if (native_module_->runtime_stub_table_[WasmCode::k##Name] == this) { \
+    return #Name;                                                       \
+  }
+#define RETURN_NAME_TRAP(Name) RETURN_NAME(ThrowWasm##Name)
+  WASM_RUNTIME_STUB_LIST(RETURN_NAME, RETURN_NAME_TRAP)
+#undef RETURN_NAME_TRAP
+#undef RETURN_NAME
+  return "<unknown>";
+}
+
 void WasmCode::Validate() const {
 #ifdef DEBUG
   // We expect certain relocation info modes to never appear in {WasmCode}
@@ -456,7 +469,7 @@ void NativeModule::SetRuntimeStubs(Isolate* isolate) {
       AddAnonymousCode(isolate->builtins()->builtin_handle(Builtins::k##Name), \
                        WasmCode::kRuntimeStub, #Name);
 #define COPY_BUILTIN_TRAP(Name) COPY_BUILTIN(ThrowWasm##Name)
-  WASM_RUNTIME_STUB_LIST(COPY_BUILTIN, COPY_BUILTIN_TRAP);
+  WASM_RUNTIME_STUB_LIST(COPY_BUILTIN, COPY_BUILTIN_TRAP)
 #undef COPY_BUILTIN_TRAP
 #undef COPY_BUILTIN
 }

src/wasm/wasm-code-manager.h

@@ -126,6 +126,8 @@ class V8_EXPORT_PRIVATE WasmCode final {
     return protected_instructions_.as_vector();
   }
 
+  const char* GetRuntimeStubName() const;
+
   void Validate() const;
   void Print(const char* name = nullptr) const;
   void Disassemble(const char* name, std::ostream& os,