MIPS[64]: Fix unaligned arguments storage in Wasm-to-interpreter entry

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 da04b3d410d54c659e4a77ae63b22026ac3ac1d8..812e66d67c5ca17e8acca99e6e518766cdfb389c 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -2976,21 +2976,50 @@ void WasmGraphBuilder::BuildWasmInterpreterEntry(
         jsgraph()->machine()->Is32() && sig->GetParam(i) == wasm::kWasmI64;
     MachineRepresentation param_rep =
         is_i64_as_two_params ? wasm::kWasmI32 : sig->GetParam(i);
-    StoreRepresentation store_rep(param_rep, WriteBarrierKind::kNoWriteBarrier);
-    *effect_ =
-        graph()->NewNode(jsgraph()->machine()->Store(store_rep), arg_buffer,
-                         Int32Constant(offset), param, *effect_, *control_);
+
+    int alignment = offset % (1 << ElementSizeLog2Of(param_rep));

[titzer, 2017/02/23 20:44:46]

What about just aligning all arguments to 64-bits?

[ivica.bogosavljevic, 2017/02/24 09:37:56]

Pfiffig!

+    bool offset_aligned = (alignment == 0);
+
+    if (offset_aligned ||
+        jsgraph()->machine()->UnalignedStoreSupported(
+            MachineType::TypeForRepresentation(param_rep), 0)) {
+      StoreRepresentation store_rep(param_rep,
+                                    WriteBarrierKind::kNoWriteBarrier);
+      *effect_ =
+          graph()->NewNode(jsgraph()->machine()->Store(store_rep), arg_buffer,
+                           Int32Constant(offset), param, *effect_, *control_);
+    } else {
+      UnalignedStoreRepresentation store_rep(param_rep);
+      *effect_ = graph()->NewNode(
+          jsgraph()->machine()->UnalignedStore(store_rep), arg_buffer,
+          Int32Constant(offset), param, *effect_, *control_);
+    }
+
     offset += 1 << ElementSizeLog2Of(param_rep);
+
     // TODO(clemensh): Respect endianess here. Might need to swap upper and
     // lower word.
     if (is_i64_as_two_params) {
       // Also store the upper half.
       param = Param(param_index++);
-      StoreRepresentation store_rep(wasm::kWasmI32,
-                                    WriteBarrierKind::kNoWriteBarrier);
-      *effect_ =
-          graph()->NewNode(jsgraph()->machine()->Store(store_rep), arg_buffer,
-                           Int32Constant(offset), param, *effect_, *control_);
+
+      alignment = offset % (1 << ElementSizeLog2Of(wasm::kWasmI32));
+      offset_aligned = (alignment == 0);
+
+      if (offset_aligned ||
+          jsgraph()->machine()->UnalignedStoreSupported(
+              MachineType::TypeForRepresentation(wasm::kWasmI32), 0)) {
+        StoreRepresentation store_rep(wasm::kWasmI32,
+                                      WriteBarrierKind::kNoWriteBarrier);
+        *effect_ =
+            graph()->NewNode(jsgraph()->machine()->Store(store_rep), arg_buffer,
+                             Int32Constant(offset), param, *effect_, *control_);
+      } else {
+        UnalignedStoreRepresentation store_rep(wasm::kWasmI32);
+        *effect_ = graph()->NewNode(
+            jsgraph()->machine()->UnalignedStore(store_rep), arg_buffer,
+            Int32Constant(offset), param, *effect_, *control_);
+      }
       offset += 1 << ElementSizeLog2Of(wasm::kWasmI32);
     }
   }
@@ -3894,7 +3923,10 @@ Handle<Code> CompileWasmInterpreterEntry(Isolate* isolate, uint32_t func_index,
   Zone zone(isolate->allocator(), ZONE_NAME);
   Graph graph(&zone);
   CommonOperatorBuilder common(&zone);
-  MachineOperatorBuilder machine(&zone);
+  MachineOperatorBuilder machine(
+      &zone, MachineType::PointerRepresentation(),
+      InstructionSelector::SupportedMachineOperatorFlags(),
+      InstructionSelector::AlignmentRequirements());
   JSGraph jsgraph(isolate, &graph, &common, nullptr, nullptr, &machine);
 
   Node* control = nullptr;