[wasm] Int64Lowering of I64Div and I64Rem.

src/compiler/wasm-compiler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/wasm-compiler.h"
 
 #include "src/isolate-inl.h"
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/platform.h"
@@ skipping 479 matching lines @@
       break;
     case wasm::kExprI64And:
       op = m->Word64And();
       break;
     // todo(ahaas): I added a list of missing instructions here to make merging
     // easier when I do them one by one.
     // kExprI64Add:
     // kExprI64Sub:
     // kExprI64Mul:
     // kExprI64DivS:
+    case wasm::kExprI64DivS:
+      return BuildI64DivS(left, right);
     // kExprI64DivU:
+    case wasm::kExprI64DivU:
+      return BuildI64DivU(left, right);
     // kExprI64RemS:
+    case wasm::kExprI64RemS:
+      return BuildI64RemS(left, right);
     // kExprI64RemU:
+    case wasm::kExprI64RemU:
+      return BuildI64RemU(left, right);
     case wasm::kExprI64Ior:
       op = m->Word64Or();
       break;
 // kExprI64Xor:
     case wasm::kExprI64Xor:
       op = m->Word64Xor();
       break;
 // kExprI64Shl:
     case wasm::kExprI64Shl:
       op = m->Word64Shl();
@@ skipping 48 matching lines @@
     // TODO(titzer): query the machine operator builder here instead of #ifdef.
     case wasm::kExprI64Add:
       op = m->Int64Add();
       break;
     case wasm::kExprI64Sub:
       op = m->Int64Sub();
       break;
     case wasm::kExprI64Mul:
       op = m->Int64Mul();
       break;
-    case wasm::kExprI64DivS: {
-      trap_->ZeroCheck64(kTrapDivByZero, right);
-      Node* before = *control_;
-      Node* denom_is_m1;
-      Node* denom_is_not_m1;
-      Branch(graph()->NewNode(jsgraph()->machine()->Word64Equal(), right,
-                              jsgraph()->Int64Constant(-1)),
-             &denom_is_m1, &denom_is_not_m1);
-      *control_ = denom_is_m1;
-      trap_->TrapIfEq64(kTrapDivUnrepresentable, left,
-                        std::numeric_limits<int64_t>::min());
-      if (*control_ != denom_is_m1) {
-        *control_ = graph()->NewNode(jsgraph()->common()->Merge(2),
-                                     denom_is_not_m1, *control_);
-      } else {
-        *control_ = before;
-      }
-      return graph()->NewNode(m->Int64Div(), left, right, *control_);
-    }
-    case wasm::kExprI64DivU:
-      op = m->Uint64Div();
-      return graph()->NewNode(op, left, right,
-                              trap_->ZeroCheck64(kTrapDivByZero, right));
-    case wasm::kExprI64RemS: {
-      trap_->ZeroCheck64(kTrapRemByZero, right);
-      Diamond d(jsgraph()->graph(), jsgraph()->common(),
-                graph()->NewNode(jsgraph()->machine()->Word64Equal(), right,
-                                 jsgraph()->Int64Constant(-1)));
-
-      Node* rem = graph()->NewNode(m->Int64Mod(), left, right, d.if_false);
-
-      return d.Phi(MachineRepresentation::kWord64, jsgraph()->Int64Constant(0),
-                   rem);
-    }
-    case wasm::kExprI64RemU:
-      op = m->Uint64Mod();
-      return graph()->NewNode(op, left, right,
-                              trap_->ZeroCheck64(kTrapRemByZero, right));
     case wasm::kExprI64Ror:
       op = m->Word64Ror();
       break;
     case wasm::kExprI64Rol:
       return BuildI64Rol(left, right);
 #endif
 
     case wasm::kExprF32CopySign:
       return BuildF32CopySign(left, right);
     case wasm::kExprF64CopySign:
@@ skipping 1145 matching lines @@
   trap_->ZeroCheck32(kTrapFloatUnrepresentable,
                      BuildCCall(sig_builder.Build(), args));
   const Operator* load_op = jsgraph()->machine()->Load(result_type);
   Node* load =
       graph()->NewNode(load_op, stack_slot_result, jsgraph()->Int32Constant(0),
                        *effect_, *control_);
   *effect_ = load;
   return load;
 }
 
+Node* WasmGraphBuilder::BuildI64DivS(Node* left, Node* right) {
+  if (jsgraph()->machine()->Is32()) {
+    return BuildDiv64Call(
+        left, right, ExternalReference::wasm_int64_div(jsgraph()->isolate()),
+        MachineType::Int64(), kTrapDivByZero);
+  } else {
+    trap_->ZeroCheck64(kTrapDivByZero, right);

[titzer, 2016/03/14 11:03:22]

Style nit: leave the else clause unnested.

[ahaas, 2016/03/14 12:38:12]

Done.

+    Node* before = *control_;
+    Node* denom_is_m1;
+    Node* denom_is_not_m1;
+    Branch(graph()->NewNode(jsgraph()->machine()->Word64Equal(), right,
+                            jsgraph()->Int64Constant(-1)),
+           &denom_is_m1, &denom_is_not_m1);
+    *control_ = denom_is_m1;
+    trap_->TrapIfEq64(kTrapDivUnrepresentable, left,
+                      std::numeric_limits<int64_t>::min());
+    if (*control_ != denom_is_m1) {
+      *control_ = graph()->NewNode(jsgraph()->common()->Merge(2),
+                                   denom_is_not_m1, *control_);
+    } else {
+      *control_ = before;
+    }
+    return graph()->NewNode(jsgraph()->machine()->Int64Div(), left, right,
+                            *control_);
+  }
+}
+
+Node* WasmGraphBuilder::BuildI64RemS(Node* left, Node* right) {
+  if (jsgraph()->machine()->Is32()) {
+    return BuildDiv64Call(
+        left, right, ExternalReference::wasm_int64_mod(jsgraph()->isolate()),
+        MachineType::Int64(), kTrapRemByZero);
+  } else {
+    trap_->ZeroCheck64(kTrapRemByZero, right);
+    Diamond d(jsgraph()->graph(), jsgraph()->common(),
+              graph()->NewNode(jsgraph()->machine()->Word64Equal(), right,
+                               jsgraph()->Int64Constant(-1)));
+
+    Node* rem = graph()->NewNode(jsgraph()->machine()->Int64Mod(), left, right,
+                                 d.if_false);
+
+    return d.Phi(MachineRepresentation::kWord64, jsgraph()->Int64Constant(0),
+                 rem);
+  }
+}
+
+Node* WasmGraphBuilder::BuildI64DivU(Node* left, Node* right) {
+  if (jsgraph()->machine()->Is32()) {
+    return BuildDiv64Call(
+        left, right, ExternalReference::wasm_uint64_div(jsgraph()->isolate()),
+        MachineType::Int64(), kTrapDivByZero);
+  } else {
+    return graph()->NewNode(jsgraph()->machine()->Uint64Div(), left, right,
+                            trap_->ZeroCheck64(kTrapDivByZero, right));
+  }
+}
+Node* WasmGraphBuilder::BuildI64RemU(Node* left, Node* right) {
+  if (jsgraph()->machine()->Is32()) {
+    return BuildDiv64Call(
+        left, right, ExternalReference::wasm_uint64_mod(jsgraph()->isolate()),
+        MachineType::Int64(), kTrapRemByZero);
+  } else {
+    return graph()->NewNode(jsgraph()->machine()->Uint64Mod(), left, right,
+                            trap_->ZeroCheck64(kTrapRemByZero, right));
+  }
+}
+
+Node* WasmGraphBuilder::BuildDiv64Call(Node* left, Node* right,
+                                       ExternalReference ref,
+                                       MachineType result_type, int trap_zero) {
+  Node* stack_slot_dst = graph()->NewNode(
+      jsgraph()->machine()->StackSlot(MachineRepresentation::kWord64));
+  Node* stack_slot_src = graph()->NewNode(
+      jsgraph()->machine()->StackSlot(MachineRepresentation::kWord64));
+
+  const Operator* store_op = jsgraph()->machine()->Store(
+      StoreRepresentation(MachineRepresentation::kWord64, kNoWriteBarrier));
+  *effect_ =
+      graph()->NewNode(store_op, stack_slot_dst, jsgraph()->Int32Constant(0),
+                       left, *effect_, *control_);
+  *effect_ =
+      graph()->NewNode(store_op, stack_slot_src, jsgraph()->Int32Constant(0),
+                       right, *effect_, *control_);
+
+  MachineSignature::Builder sig_builder(jsgraph()->zone(), 1, 2);
+  sig_builder.AddReturn(MachineType::Int32());
+  sig_builder.AddParam(MachineType::Pointer());
+  sig_builder.AddParam(MachineType::Pointer());
+
+  Node* function = graph()->NewNode(jsgraph()->common()->ExternalConstant(ref));
+  Node* args[] = {function, stack_slot_dst, stack_slot_src};
+
+  Node* call = BuildCCall(sig_builder.Build(), args);
+  trap_->ZeroCheck32(static_cast<TrapReason>(trap_zero), call);

[titzer, 2016/03/14 11:03:22]

Can you leave a TODO here? This can get simpler if we have a specialized runtime
call to throw WASM exceptions by trap code instead of by string.

[ahaas, 2016/03/14 12:38:12]

Done.

+  trap_->TrapIfEq32(kTrapDivUnrepresentable, call, -1);
+  const Operator* load_op = jsgraph()->machine()->Load(result_type);
+  Node* load =
+      graph()->NewNode(load_op, stack_slot_dst, jsgraph()->Int32Constant(0),
+                       *effect_, *control_);
+  *effect_ = load;
+  return load;
+}
+
 Node* WasmGraphBuilder::BuildCCall(MachineSignature* sig, Node** args) {
   const size_t params = sig->parameter_count();
   const size_t extra = 2;  // effect and control inputs.
   const size_t count = 1 + params + extra;
 
   // Reallocate the buffer to make space for extra inputs.
   args = Realloc(args, count);
 
   // Add effect and control inputs.
   args[params + 1] = *effect_;
@@ skipping 787 matching lines @@
         static_cast<int>(function.code_end_offset - function.code_start_offset),
         decode_ms, compile_ms);
   }
   return code;
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8