[wasm] OOB traps: build protected instruction list during codegen

src/wasm/wasm-module.cc

Index: src/wasm/wasm-module.cc
diff --git a/src/wasm/wasm-module.cc b/src/wasm/wasm-module.cc
index f70467f50dcf87d22122630323370c717fc899fb..6d45ebe32a015141d75f1eb683e2f6e2c601bc41 100644
--- a/src/wasm/wasm-module.cc
+++ b/src/wasm/wasm-module.cc
@@ -1255,6 +1255,37 @@ class WasmInstanceBuilder {
     FlushICache(isolate_, code_table);
 
     //--------------------------------------------------------------------------
+    // Unpack and notify signal handler of protected instructions.
+    //--------------------------------------------------------------------------
+    {
+      for (int i = 0; i < code_table->length(); ++i) {
+        Handle<Code> code = code_table->GetValueChecked<Code>(isolate_, i);
+
+        if (code->kind() != Code::WASM_FUNCTION) {
+          continue;
+        }
+
+        FixedArray* protected_instructions = code->protected_instructions();
+
+        ProtectedInstructionList unpacked;
+        for (int i = 0; i < protected_instructions->length();
+             i += kTrapDataSize) {
+          ProtectedInstructionData data;
+          data.instr_offset =
+              protected_instructions
+                  ->GetValueChecked<Smi>(isolate_, i + kTrapCodeOffset)
+                  ->value();
+          data.landing_offset =
+              protected_instructions
+                  ->GetValueChecked<Smi>(isolate_, i + kTrapLandingOffset)
+                  ->value();
+          unpacked.push_back(data);
+        }
+        // TODO(eholk): Register the protected instruction information once the
+        // trap handler is in place.
+      }
+    }
+
     // Set up and link the new instance.
     //--------------------------------------------------------------------------
     {