[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..b023b3d23ecc68f136c48a236a24d6da416f20e7 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -45,6 +45,7 @@
 
 namespace v8 {
 namespace internal {
+
 namespace compiler {
 
 namespace {
@@ -2751,7 +2752,6 @@ void WasmGraphBuilder::BoundsCheckMem(MachineType memtype, Node* index,
   trap_->AddTrapIfFalse(wasm::kTrapMemOutOfBounds, cond, position);
 }
 
-

[Mircea Trofin, 2016/09/02 04:05:45]

We want to keep this space here. Did "git cl upload" not complain?

[Eric Holk, 2016/09/02 20:05:32]

Done.

 Node* WasmGraphBuilder::LoadMem(wasm::LocalType type, MachineType memtype,
                                 Node* index, uint32_t offset,
                                 uint32_t alignment,
@@ -2759,15 +2759,26 @@ 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) {
+      load = graph()->NewNode(jsgraph()->machine()->Load(memtype),
+                              MemBuffer(offset), index, *effect_, *control_);
+    } else {
+      auto* context = HeapConstant(module_->instance->context);

[Mircea Trofin, 2016/09/02 04:05:45]

HeapConstant* instead of auto. AFAIK, auto would have been fine if this were an
instantiation. It's a function call.

[Eric Holk, 2016/09/02 20:05:32]

Done. It was actually Node* instead of HeapConstant*.

+      auto position_node = jsgraph()->Int32Constant(position);
+      load = graph()->NewNode(jsgraph()->machine()->ProtectedLoad(memtype),

[Mircea Trofin, 2016/09/02 04:05:45]

What's position_node's type? (i.e. please no auto)

[Eric Holk, 2016/09/02 20:05:32]

Done. This was also Node*.

+                              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_);
   }