[wasm] Break loops in the module-decoder upon error.

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 0aa620722949803b3e733159b5ea10d50a24cea9..7a602110f90b9bfb674e330e12eeec7e92e219e5 100644
--- a/src/wasm/module-decoder.cc
+++ b/src/wasm/module-decoder.cc
@@ -187,6 +187,7 @@ class ModuleDecoder : public Decoder {
             break;
           }
           for (uint32_t i = 0; i < functions_count; ++i) {
+            if (failed()) break;

[titzer, 2016/09/22 09:53:11]

Can we change all these loops to be for(x, ok() && y; x++)?

This is the format I've used in 0xC

[ahaas, 2016/09/22 12:35:09]

Done.

             WasmFunction* function = &module->functions[i];
             uint32_t size = consume_u32v("body size");
             function->code_start_offset = pc_offset();
@@ -212,12 +213,14 @@ class ModuleDecoder : public Decoder {
           }
 
           for (uint32_t i = 0; i < functions_count; ++i) {
+            if (failed()) break;
             WasmFunction* function = &module->functions[i];
             function->name_offset =
                 consume_string(&function->name_length, false);
 
             uint32_t local_names_count = consume_u32v("local names count");
             for (uint32_t j = 0; j < local_names_count; j++) {
+              if (failed()) break;
               uint32_t unused = 0;
               uint32_t offset = consume_string(&unused, false);
               USE(unused);
@@ -519,6 +522,7 @@ class ModuleDecoder : public Decoder {
     }
 
     for (uint32_t i = 0; i < table->size; ++i) {
+      if (failed()) break;
       uint16_t index = consume_u32v();
       if (index >= module->functions.size()) {
         error(pc_ - sizeof(index), "invalid function index");