[wasm] Initial signal handler

test/cctest/wasm/test-wasm-trap-position.cc

Index: test/cctest/wasm/test-wasm-trap-position.cc
diff --git a/test/cctest/wasm/test-wasm-trap-position.cc b/test/cctest/wasm/test-wasm-trap-position.cc
index 0418d46bab34e6718431046415fb3f6ea52e799c..ab73edd66470ceee1cd7f677759e290b83c5c9f0 100644
--- a/test/cctest/wasm/test-wasm-trap-position.cc
+++ b/test/cctest/wasm/test-wasm-trap-position.cc
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "src/trap-handler/trap-handler.h"
 #include "src/wasm/wasm-macro-gen.h"
 
 #include "test/cctest/cctest.h"
@@ -97,6 +98,11 @@ TEST(Unreachable) {
 
 // Trigger a trap for loading from out-of-bounds.
 TEST(IllegalLoad) {
+  if (trap_handler::ShouldEnableTrapHandler()) {
+    // cctests don't register the handler data, so this test won't work

[ahaas, 2017/02/20 09:27:24]

Runtime calls don't work in cctests, so I guess you never set the flag that wasm
code is executed.

[Eric Holk, 2017/02/23 02:16:57]

Acknowledged.

+    // TODO(eholk): find out why and fix it.

[Mark Seaborn, 2017/02/17 21:41:12]

Does this need to get fixed?

[Eric Holk, 2017/02/23 02:16:57]

This test just does the basic out of bounds memory access test, which we have
covered in the mjsunit tests, and those do run. I think we should fix this, but
I'd rather do it in a followup CL.

I did realize the comment was a bit out of date. The immediate problem is that
r.module().AddMemory down below doesn't create the guard pages, so our signal
handler never runs. I've updated the comment here to reflect this.

+    return;
+  }
   WasmRunner<void> r(kExecuteCompiled);
   TestSignatures sigs;
   // Set the execution context, such that a runtime error can be thrown.