[wasm][i64-lowering] Refactor special CallDescriptor lowering

This CL generalizes the lowering of special CallDescriptors in the
int64-lowering. The reason is a planned extension of the special
handling due to a refactoring of the AtomicWait implementation.

R=jkummerow@chromium.org

Bug: v8:10108
Change-Id: I48d0087e2ad00ba9b44c5198ffdbbae8eb575a85
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2069333Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66420}

src/compiler/int64-lowering.cc

@@ -1023,14 +1023,12 @@ bool Int64Lowering::DefaultLowering(Node* node, bool low_word_only) {
   return something_changed;
 }
 
-CallDescriptor* Int64Lowering::LowerCallDescriptor(
+const CallDescriptor* Int64Lowering::LowerCallDescriptor(
     const CallDescriptor* call_descriptor) {
   if (special_case_) {
-    if (call_descriptor == special_case_->bigint_to_i64_call_descriptor) {
-      return special_case_->bigint_to_i32_pair_call_descriptor;
-    }
-    if (call_descriptor == special_case_->i64_to_bigint_call_descriptor) {
-      return special_case_->i32_pair_to_bigint_call_descriptor;
+    auto replacement = special_case_->replacements.find(call_descriptor);
+    if (replacement != special_case_->replacements.end()) {
+      return replacement->second;
     }
   }
   return GetI32WasmCallDescriptor(zone(), call_descriptor);

src/compiler/int64-lowering.h

@@ -24,19 +24,9 @@ namespace compiler {
 
 // Struct for CallDescriptors that need special lowering.
 struct V8_EXPORT_PRIVATE Int64LoweringSpecialCase {
-  Int64LoweringSpecialCase()
-      : bigint_to_i64_call_descriptor(nullptr),
-        i64_to_bigint_call_descriptor(nullptr),
-        bigint_to_i32_pair_call_descriptor(nullptr),
-        i32_pair_to_bigint_call_descriptor(nullptr) {}
-
-  // CallDescriptors that need special lowering.
-  CallDescriptor* bigint_to_i64_call_descriptor;
-  CallDescriptor* i64_to_bigint_call_descriptor;
-
-  // The replacement CallDescriptors.
-  CallDescriptor* bigint_to_i32_pair_call_descriptor;
-  CallDescriptor* i32_pair_to_bigint_call_descriptor;
+  // Map from CallDescriptors that should be replaced, to the replacement
+  // CallDescriptors.
+  std::unordered_map<const CallDescriptor*, const CallDescriptor*> replacements;
 };
 
 class V8_EXPORT_PRIVATE Int64Lowering {
@@ -74,7 +64,8 @@ class V8_EXPORT_PRIVATE Int64Lowering {
   void LowerWord64AtomicBinop(Node* node, const Operator* op);
   void LowerWord64AtomicNarrowOp(Node* node, const Operator* op);
 
-  CallDescriptor* LowerCallDescriptor(const CallDescriptor* call_descriptor);
+  const CallDescriptor* LowerCallDescriptor(
+      const CallDescriptor* call_descriptor);
 
   void ReplaceNode(Node* old, Node* new_low, Node* new_high);
   bool HasReplacementLow(Node* node);

src/compiler/wasm-compiler.cc

@@ -5073,6 +5073,19 @@ void WasmGraphBuilder::RemoveBytecodePositionDecorator() {
 }
 
 namespace {
+template <typename BuiltinDescriptor>
+CallDescriptor* GetBuiltinCallDescriptor(WasmGraphBuilder* builder,
+                                         StubCallMode stub_mode) {
+  BuiltinDescriptor interface_descriptor;
+  return Linkage::GetStubCallDescriptor(
+      builder->mcgraph()->zone(),                     // zone
+      interface_descriptor,                           // descriptor
+      interface_descriptor.GetStackParameterCount(),  // stack parameter count
+      CallDescriptor::kNoFlags,                       // flags
+      Operator::kNoProperties,                        // properties
+      stub_mode);                                     // stub call mode
+}
+
 class WasmWrapperGraphBuilder : public WasmGraphBuilder {
  public:
   WasmWrapperGraphBuilder(Zone* zone, MachineGraph* mcgraph,
@@ -5083,76 +5096,34 @@ class WasmWrapperGraphBuilder : public WasmGraphBuilder {
         stub_mode_(stub_mode),
         enabled_features_(features) {}
 
-  CallDescriptor* GetI32PairToBigIntCallDescriptor() {
-    I32PairToBigIntDescriptor interface_descriptor;
-
-    return Linkage::GetStubCallDescriptor(
-        mcgraph()->zone(),                              // zone
-        interface_descriptor,                           // descriptor
-        interface_descriptor.GetStackParameterCount(),  // stack parameter count
-        CallDescriptor::kNoFlags,                       // flags
-        Operator::kNoProperties,                        // properties
-        stub_mode_);                                    // stub call mode
-  }
-
   CallDescriptor* GetI64ToBigIntCallDescriptor() {
+    if (i64_to_bigint_descriptor_) return i64_to_bigint_descriptor_;
+    i64_to_bigint_descriptor_ =
+        GetBuiltinCallDescriptor<I64ToBigIntDescriptor>(this, stub_mode_);
     if (!lowering_special_case_) {
       lowering_special_case_ = std::make_unique<Int64LoweringSpecialCase>();
     }
-
-    if (lowering_special_case_->i64_to_bigint_call_descriptor) {
-      return lowering_special_case_->i64_to_bigint_call_descriptor;
-    }
-
-    I64ToBigIntDescriptor interface_descriptor;
-    auto call_descriptor = Linkage::GetStubCallDescriptor(
-        mcgraph()->zone(),                              // zone
-        interface_descriptor,                           // descriptor
-        interface_descriptor.GetStackParameterCount(),  // stack parameter count
-        CallDescriptor::kNoFlags,                       // flags
-        Operator::kNoProperties,                        // properties
-        stub_mode_);                                    // stub call mode
-
-    lowering_special_case_->i64_to_bigint_call_descriptor = call_descriptor;
-    lowering_special_case_->i32_pair_to_bigint_call_descriptor =
-        GetI32PairToBigIntCallDescriptor();
-    return call_descriptor;
-  }
-
-  CallDescriptor* GetBigIntToI32PairCallDescriptor() {
-    BigIntToI32PairDescriptor interface_descriptor;
-
-    return Linkage::GetStubCallDescriptor(
-        mcgraph()->zone(),                              // zone
-        interface_descriptor,                           // descriptor
-        interface_descriptor.GetStackParameterCount(),  // stack parameter count
-        CallDescriptor::kNoFlags,                       // flags
-        Operator::kNoProperties,                        // properties
-        stub_mode_);                                    // stub call mode
+    lowering_special_case_->replacements.insert(
+        {i64_to_bigint_descriptor_,
+         GetBuiltinCallDescriptor<I32PairToBigIntDescriptor>(this,
+                                                             stub_mode_)});
+    return i64_to_bigint_descriptor_;
   }
 
   CallDescriptor* GetBigIntToI64CallDescriptor() {
+    if (bigint_to_i64_descriptor_) return bigint_to_i64_descriptor_;
     if (!lowering_special_case_) {
       lowering_special_case_ = std::make_unique<Int64LoweringSpecialCase>();
     }
 
-    if (lowering_special_case_->bigint_to_i64_call_descriptor) {
-      return lowering_special_case_->bigint_to_i64_call_descriptor;
-    }
-
-    BigIntToI64Descriptor interface_descriptor;
-    auto call_descriptor = Linkage::GetStubCallDescriptor(
-        mcgraph()->zone(),                              // zone
-        interface_descriptor,                           // descriptor
-        interface_descriptor.GetStackParameterCount(),  // stack parameter count
-        CallDescriptor::kNoFlags,                       // flags
-        Operator::kNoProperties,                        // properties
-        stub_mode_);                                    // stub call mode
+    bigint_to_i64_descriptor_ =
+        GetBuiltinCallDescriptor<BigIntToI64Descriptor>(this, stub_mode_);
 
-    lowering_special_case_->bigint_to_i64_call_descriptor = call_descriptor;
-    lowering_special_case_->bigint_to_i32_pair_call_descriptor =
-        GetBigIntToI32PairCallDescriptor();
-    return call_descriptor;
+    lowering_special_case_->replacements.insert(
+        {bigint_to_i64_descriptor_,
+         GetBuiltinCallDescriptor<BigIntToI32PairDescriptor>(this,
+                                                             stub_mode_)});
+    return bigint_to_i64_descriptor_;
   }
 
   Node* GetBuiltinPointerTarget(Builtins::Name builtin_id) {
@@ -6307,6 +6278,8 @@ class WasmWrapperGraphBuilder : public WasmGraphBuilder {
   SetOncePointer<Node> undefined_value_node_;
   SetOncePointer<const Operator> allocate_heap_number_operator_;
   wasm::WasmFeatures enabled_features_;
+  CallDescriptor* bigint_to_i64_descriptor_ = nullptr;
+  CallDescriptor* i64_to_bigint_descriptor_ = nullptr;
 };
 
 }  // namespace

test/unittests/compiler/int64-lowering-unittest.cc

@@ -1016,10 +1016,8 @@ TEST_F(Int64LoweringTest, WasmBigIntSpecialCaseBigIntToI64) {
           StubCallMode::kCallCodeObject);  // stub call mode
 
   auto lowering_special_case = std::make_unique<Int64LoweringSpecialCase>();
-  lowering_special_case->bigint_to_i64_call_descriptor =
-      bigint_to_i64_call_descriptor;
-  lowering_special_case->bigint_to_i32_pair_call_descriptor =
-      bigint_to_i32_pair_call_descriptor;
+  lowering_special_case->replacements.insert(
+      {bigint_to_i64_call_descriptor, bigint_to_i32_pair_call_descriptor});
 
   Node* call_node =
       graph()->NewNode(common()->Call(bigint_to_i64_call_descriptor), target,
@@ -1064,10 +1062,8 @@ TEST_F(Int64LoweringTest, WasmBigIntSpecialCaseI64ToBigInt) {
           StubCallMode::kCallCodeObject);  // stub call mode
 
   auto lowering_special_case = std::make_unique<Int64LoweringSpecialCase>();
-  lowering_special_case->i64_to_bigint_call_descriptor =
-      i64_to_bigint_call_descriptor;
-  lowering_special_case->i32_pair_to_bigint_call_descriptor =
-      i32_pair_to_bigint_call_descriptor;
+  lowering_special_case->replacements.insert(
+      {i64_to_bigint_call_descriptor, i32_pair_to_bigint_call_descriptor});
 
   Node* call = graph()->NewNode(common()->Call(i64_to_bigint_call_descriptor),
                                 target, i64, start(), start());