[wasm] check that there is at most 1 table

R=titzer@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2643783002
Cr-Commit-Position: refs/heads/master@{#42465}

src/wasm/module-decoder.cc

@@ -304,6 +304,7 @@ class ModuleDecoder : public Decoder {
           }
           case kExternalTable: {
             // ===== Imported table ==========================================
+            if (!AddTable(module)) break;
             import->index =
                 static_cast<uint32_t>(module->function_tables.size());
             module->function_tables.push_back({0, 0, false,
@@ -319,11 +320,11 @@ class ModuleDecoder : public Decoder {
           }
           case kExternalMemory: {
             // ===== Imported memory =========================================
+            if (!AddMemory(module)) break;
             consume_resizable_limits(
                 "memory", "pages", kV8MaxWasmMemoryPages,
                 &module->min_mem_pages, &module->has_max_mem,
                 kSpecMaxWasmMemoryPages, &module->max_mem_pages);
-            SetHasMemory(module);
             break;
           }
           case kExternalGlobal: {
@@ -373,12 +374,11 @@ class ModuleDecoder : public Decoder {
     // ===== Table section ===================================================
     if (section_iter.section_code() == kTableSectionCode) {
       uint32_t table_count = consume_count("table count", kV8MaxWasmTables);
-      if (module->function_tables.size() < 1) {
-        module->function_tables.push_back({0, 0, false, std::vector<int32_t>(),
-                                           false, false, SignatureMap()});
-      }
 
       for (uint32_t i = 0; ok() && i < table_count; i++) {
+        if (!AddTable(module)) break;
+        module->function_tables.push_back({0, 0, false, std::vector<int32_t>(),
+                                           false, false, SignatureMap()});
         WasmIndirectFunctionTable* table = &module->function_tables.back();
         expect_u8("table type", kWasmAnyFunctionTypeForm);
         consume_resizable_limits(
@@ -393,12 +393,12 @@ class ModuleDecoder : public Decoder {
       uint32_t memory_count = consume_count("memory count", kV8MaxWasmMemories);
 
       for (uint32_t i = 0; ok() && i < memory_count; i++) {
+        if (!AddMemory(module)) break;
         consume_resizable_limits("memory", "pages", kV8MaxWasmMemoryPages,
                                  &module->min_mem_pages, &module->has_max_mem,
                                  kSpecMaxWasmMemoryPages,
                                  &module->max_mem_pages);
       }
-      SetHasMemory(module);
       section_iter.advance();
     }
 
@@ -683,11 +683,22 @@ class ModuleDecoder : public Decoder {
 
   uint32_t off(const byte* ptr) { return static_cast<uint32_t>(ptr - start_); }
 
-  void SetHasMemory(WasmModule* module) {
+  bool AddTable(WasmModule* module) {
+    if (module->function_tables.size() > 0) {
+      error("At most one table is supported");
+      return false;
+    } else {
+      return true;
+    }
+  }
+
+  bool AddMemory(WasmModule* module) {
     if (module->has_memory) {
-      error("At most one memory object is supported");
+      error("At most one memory is supported");
+      return false;
     } else {
       module->has_memory = true;
+      return true;
     }
   }
 

test/mjsunit/wasm/indirect-tables.js

@@ -319,9 +319,8 @@ function js_div(a, b) { return (a / b) | 0; }
       kExprCallIndirect, sig_index2, kTableZero])  // --
     .exportAs("main");
 
-  builder.setFunctionTableLength(kTableSize);
-  builder.addFunctionTableInit(1, false, [f2.index]);
   builder.addImportedTable("z", "table", kTableSize, kTableSize);
+  builder.addFunctionTableInit(1, false, [f2.index], true);
 
   var m2 = new WebAssembly.Module(builder.toBuffer());
 

test/mjsunit/wasm/wasm-module-builder.js

@@ -227,12 +227,12 @@ class WasmModuleBuilder {
     this.exports.push({name: name, kind: kExternalMemory, index: 0});
   }
 
-  addFunctionTableInit(base, is_global, array) {
+  addFunctionTableInit(base, is_global, array, is_import = false) {
     this.function_table_inits.push({base: base, is_global: is_global,
                                     array: array});
     if (!is_global) {
       var length = base + array.length;
-      if (length > this.function_table_length) {
+      if (length > this.function_table_length && !is_import) {
         this.function_table_length = length;
       }
     }