[wasm] Fix serialization of {WasmCode} with jump tables.

This correctly serializes {RelocInfo::INTERNAL_REFERENCE} addresses in a
position-independent form, so that they can be properly relocated when
the code is deserialized again. We store the offset within the code in
the serialized stream.

R=clemensh@chromium.org
TEST=mjsunit/wasm/compiled-module-serialization
BUG=chromium:857049

Change-Id: Ie8c84ee67bdfc17a65faa159a21cc1f2a78ac924
Reviewed-on: https://chromium-review.googlesource.com/1122414Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54140}

src/wasm/wasm-serialization.cc

@@ -315,7 +315,9 @@ void NativeModuleSerializer::WriteCode(const WasmCode* code, Writer* writer) {
   // Relocate the code.
   int mask = RelocInfo::ModeMask(RelocInfo::WASM_CALL) |
              RelocInfo::ModeMask(RelocInfo::WASM_STUB_CALL) |
-             RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE);
+             RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
+             RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE) |
+             RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE_ENCODED);
   RelocIterator orig_iter(code->instructions(), code->reloc_info(),
                           code->constant_pool(), mask);
   for (RelocIterator iter(
@@ -345,6 +347,13 @@ void NativeModuleSerializer::WriteCode(const WasmCode* code, Writer* writer) {
         uint32_t tag = ref_iter->second;
         SetWasmCalleeTag(iter.rinfo(), tag);
       } break;
+      case RelocInfo::INTERNAL_REFERENCE:
+      case RelocInfo::INTERNAL_REFERENCE_ENCODED: {
+        Address orig_target = orig_iter.rinfo()->target_internal_reference();
+        Address offset = orig_target - code->instruction_start();
+        Assembler::deserialization_set_target_internal_reference_at(
+            iter.rinfo()->pc(), offset, mode);
+      } break;
       default:
         UNREACHABLE();
     }
@@ -463,7 +472,9 @@ bool NativeModuleDeserializer::ReadCode(uint32_t fn_index, Reader* reader) {
   // Relocate the code.
   int mask = RelocInfo::ModeMask(RelocInfo::WASM_CALL) |
              RelocInfo::ModeMask(RelocInfo::WASM_STUB_CALL) |
-             RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE);
+             RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
+             RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE) |
+             RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE_ENCODED);
   for (RelocIterator iter(code->instructions(), code->reloc_info(),
                           code->constant_pool(), mask);
        !iter.done(); iter.next()) {
@@ -492,6 +503,14 @@ bool NativeModuleDeserializer::ReadCode(uint32_t fn_index, Reader* reader) {
         iter.rinfo()->set_target_external_reference(address, SKIP_ICACHE_FLUSH);
         break;
       }
+      case RelocInfo::INTERNAL_REFERENCE:
+      case RelocInfo::INTERNAL_REFERENCE_ENCODED: {
+        Address offset = iter.rinfo()->target_internal_reference();
+        Address target = code->instruction_start() + offset;
+        Assembler::deserialization_set_target_internal_reference_at(
+            iter.rinfo()->pc(), target, mode);
+        break;
+      }
       default:
         UNREACHABLE();
     }

test/mjsunit/wasm/compiled-module-serialization.js

@@ -352,3 +352,55 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
 
   assertEquals(65, instance.exports.main());
 })();
+
+(function BranchTableAfterSerialization() {
+  print(arguments.callee.name);
+  const builder = new WasmModuleBuilder();
+  builder.addFunction('main', kSig_i_i)
+      .addBody([kExprBlock, kWasmStmt,
+                  kExprBlock, kWasmStmt,
+                    kExprBlock, kWasmStmt,
+                      kExprBlock, kWasmStmt,
+                        kExprBlock, kWasmStmt,
+                          kExprBlock, kWasmStmt,
+                            kExprBlock, kWasmStmt,
+                              kExprGetLocal, 0,
+                              kExprBrTable, 6, 0, 1, 2, 3, 4, 5, 6,
+                            kExprEnd,
+                            kExprI32Const, 3,
+                            kExprReturn,
+                          kExprEnd,
+                          kExprI32Const, 7,
+                          kExprReturn,
+                        kExprEnd,
+                        kExprI32Const, 9,
+                        kExprReturn,
+                      kExprEnd,
+                      kExprI32Const, 11,
+                      kExprReturn,
+                    kExprEnd,
+                    kExprI32Const, 23,
+                    kExprReturn,
+                  kExprEnd,
+                  kExprI32Const, 35,
+                  kExprReturn,
+                kExprEnd,
+                kExprI32Const, 42,
+                kExprReturn])
+      .exportFunc();
+
+  var wire_bytes = builder.toBuffer();
+  var module = new WebAssembly.Module(wire_bytes);
+  var buffer = %SerializeWasmModule(module);
+  module = %DeserializeWasmModule(buffer, wire_bytes);
+  var instance = new WebAssembly.Instance(module);
+
+  assertEquals(3, instance.exports.main(0));
+  assertEquals(7, instance.exports.main(1));
+  assertEquals(9, instance.exports.main(2));
+  assertEquals(11, instance.exports.main(3));
+  assertEquals(23, instance.exports.main(4));
+  assertEquals(35, instance.exports.main(5));
+  assertEquals(42, instance.exports.main(6));
+  assertEquals(42, instance.exports.main(9));
+})();