[wasm] Support undefined indirect table entries, behind a flag.

src/wasm/module-decoder.cc

Index: src/wasm/module-decoder.cc
diff --git a/src/wasm/module-decoder.cc b/src/wasm/module-decoder.cc
index 8ea4802ef40ea8baf81c966314582cae47d6b8d4..2ac2f9eafaad2e848dcb102d5c671cc0a1fdc551 100644
--- a/src/wasm/module-decoder.cc
+++ b/src/wasm/module-decoder.cc
@@ -270,6 +270,20 @@ class ModuleDecoder : public Decoder {
           }
           break;
         }
+        case WasmSection::Code::FunctionTablePad: {
+          if (!FLAG_wasm_jit_prototype) {
+            error("FunctionTablePad section without jiting enabled");
+          }
+          // An indirect function table requires functions first.
+          int length;
+          module->indirect_table_size =
+              consume_u32v(&length, "indirect entry count");
+          if (module->indirect_table_size > 0 &&
+              module->indirect_table_size < module->function_table.size()) {
+            error("more predefined indirect entries than table can hold");
+          }
+          break;
+        }
         case WasmSection::Code::FunctionTable: {
           // An indirect function table requires functions first.
           CheckForFunctions(module, section);
@@ -289,6 +303,10 @@ class ModuleDecoder : public Decoder {
             }
             module->function_table.push_back(index);
           }
+          if (module->indirect_table_size > 0 &&
+              module->indirect_table_size < module->function_table.size()) {
+            error("more predefined indirect entries than table can hold");
+          }
           break;
         }
         case WasmSection::Code::StartFunction: {