[wasm] Trap handling: ProtectedLoad instruction

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index 35e78b6aa2a617ad7241d5e2b33e10419e8dc920..1d9c68c229da8a14573e1754f295deec00e762db 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -45,6 +45,7 @@
 
 namespace v8 {
 namespace internal {
+
 namespace compiler {
 
 namespace {
@@ -2759,15 +2760,26 @@ Node* WasmGraphBuilder::LoadMem(wasm::LocalType type, MachineType memtype,
   Node* load;
 
   // WASM semantics throw on OOB. Introduce explicit bounds check.
-  BoundsCheckMem(memtype, index, offset, position);
+  if (!FLAG_wasm_trap_handler) {
+    BoundsCheckMem(memtype, index, offset, position);
+  }
   bool aligned = static_cast<int>(alignment) >=
                  ElementSizeLog2Of(memtype.representation());
 
   if (aligned ||
       jsgraph()->machine()->UnalignedLoadSupported(memtype, alignment)) {
-    load = graph()->NewNode(jsgraph()->machine()->Load(memtype),
-                            MemBuffer(offset), index, *effect_, *control_);
+    if (!FLAG_wasm_trap_handler) {

[titzer, 2016/09/08 17:06:35]

Flip sense of if?

[Eric Holk, 2016/09/08 21:11:56]

Done.

+      load = graph()->NewNode(jsgraph()->machine()->Load(memtype),
+                              MemBuffer(offset), index, *effect_, *control_);
+    } else {
+      Node* context = HeapConstant(module_->instance->context);
+      Node* position_node = jsgraph()->Int32Constant(position);
+      load = graph()->NewNode(jsgraph()->machine()->ProtectedLoad(memtype),
+                              MemBuffer(offset), index, context, position_node,
+                              *effect_, *control_);
+    }
   } else {
+    DCHECK(!FLAG_wasm_trap_handler);
     load = graph()->NewNode(jsgraph()->machine()->UnalignedLoad(memtype),
                             MemBuffer(offset), index, *effect_, *control_);
   }