MIPS[64]: Reland of `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 bb984253017de9addbbc353615b0fb36e91b669a..b4059e59a00dd670b9ff2e415a96f3f05e765856 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -2800,7 +2800,8 @@ void WasmGraphBuilder::BuildWasmInterpreterEntry(
   // Compute size for the argument buffer.
   int args_size_bytes = 0;
   for (int i = 0; i < wasm_count; i++) {
-    args_size_bytes += 1 << ElementSizeLog2Of(sig->GetParam(i));
+    args_size_bytes +=
+        RoundUpToMultipleOfPowOf2(1 << ElementSizeLog2Of(sig->GetParam(i)), 8);
   }
 
   // The return value is also passed via this buffer:
@@ -2811,10 +2812,11 @@ void WasmGraphBuilder::BuildWasmInterpreterEntry(
       sig->return_count() == 0 ? 0 : 1 << ElementSizeLog2Of(sig->GetReturn(0));
 
   // Get a stack slot for the arguments.
-  Node* arg_buffer = args_size_bytes == 0 && return_size_bytes == 0
-                         ? jsgraph()->IntPtrConstant(0)
-                         : graph()->NewNode(jsgraph()->machine()->StackSlot(
-                               std::max(args_size_bytes, return_size_bytes)));
+  Node* arg_buffer =
+      args_size_bytes == 0 && return_size_bytes == 0
+          ? jsgraph()->IntPtrConstant(0)
+          : graph()->NewNode(jsgraph()->machine()->StackSlot(
+                std::max(args_size_bytes, return_size_bytes), 8));

[Clemens Hammacher, 2017/05/18 11:52:05]

Wouldn't this be the only change required?

[ivica.bogosavljevic, 2017/05/18 12:21:43]

Unfortunately no. if you had three parameters, first 4 bytes, second 8 bytes and
third 8 bytes, the first parameter would be 8 byte aligned but second and third
wouldn't.

 
   // Now store all our arguments to the buffer.
   int param_index = 0;
@@ -2845,7 +2847,8 @@ void WasmGraphBuilder::BuildWasmInterpreterEntry(
       *effect_ =
           graph()->NewNode(jsgraph()->machine()->Store(store_rep), arg_buffer,
                            Int32Constant(offset), param, *effect_, *control_);
-      offset += 1 << ElementSizeLog2Of(param_rep);
+
+      offset += RoundUpToMultipleOfPowOf2(1 << ElementSizeLog2Of(param_rep), 8);
     }
   }
   DCHECK_EQ(param_count, param_index);
@@ -3841,7 +3844,10 @@ 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;