[wasm] Access "CEntryStub" from the root set.

This removes a shortcut to a "CEntryStub" from the instance object and
instead loads those values via the root set which is also referenced
from the instance. It makes instance objects smaller.

R=clemensh@chromium.org

Change-Id: I2e77cf2cb6949873bb461fb1ed0787e4a413aa5f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1714656
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62888}

src/builtins/arm/builtins-arm.cc

@@ -2517,7 +2517,10 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
     __ push(kWasmCompileLazyFuncIndexRegister);
     // Load the correct CEntry builtin from the instance object.
     __ ldr(r2, FieldMemOperand(kWasmInstanceRegister,
-                               WasmInstanceObject::kCEntryStubOffset));
+                               WasmInstanceObject::kIsolateRootOffset));
+    auto centry_id =
+        Builtins::kCEntry_Return1_DontSaveFPRegs_ArgvOnStack_NoBuiltinExit;
+    __ ldr(r2, MemOperand(r2, IsolateData::builtin_slot_offset(centry_id)));
     // Initialize the JavaScript context with 0. CEntry will use it to
     // set the current context on the isolate.
     __ Move(cp, Smi::zero());

src/builtins/arm64/builtins-arm64.cc

@@ -3031,9 +3031,12 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
     // function.
     __ Push(kWasmInstanceRegister, kWasmCompileLazyFuncIndexRegister);
     // Load the correct CEntry builtin from the instance object.
+    __ Ldr(x2, FieldMemOperand(kWasmInstanceRegister,
+                               WasmInstanceObject::kIsolateRootOffset));
+    auto centry_id =
+        Builtins::kCEntry_Return1_DontSaveFPRegs_ArgvOnStack_NoBuiltinExit;
     __ LoadTaggedPointerField(
-        x2, FieldMemOperand(kWasmInstanceRegister,
-                            WasmInstanceObject::kCEntryStubOffset));
+        x2, MemOperand(x2, IsolateData::builtin_slot_offset(centry_id)));
     // Initialize the JavaScript context with 0. CEntry will use it to
     // set the current context on the isolate.
     __ Mov(cp, Smi::zero());

src/builtins/builtins-wasm-gen.cc

@@ -46,10 +46,16 @@ class WasmBuiltinsAssembler : public CodeStubAssembler {
   }
 
   TNode<Code> LoadCEntryFromInstance(TNode<Object> instance) {
-    return UncheckedCast<Code>(
-        Load(MachineType::AnyTagged(), instance,
-             IntPtrConstant(WasmInstanceObject::kCEntryStubOffset -
+    TNode<IntPtrT> isolate_root = UncheckedCast<IntPtrT>(
+        Load(MachineType::Pointer(), instance,
+             IntPtrConstant(WasmInstanceObject::kIsolateRootOffset -
                             kHeapObjectTag)));
+    auto centry_id =
+        Builtins::kCEntry_Return1_DontSaveFPRegs_ArgvOnStack_NoBuiltinExit;
+    TNode<Code> target = UncheckedCast<Code>(
+        Load(MachineType::TaggedPointer(), isolate_root,
+             IntPtrConstant(IsolateData::builtin_slot_offset(centry_id))));
+    return target;
   }
 };
 

src/builtins/ia32/builtins-ia32.cc

@@ -2676,7 +2676,10 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
     __ Push(kWasmCompileLazyFuncIndexRegister);
     // Load the correct CEntry builtin from the instance object.
     __ mov(ecx, FieldOperand(kWasmInstanceRegister,
-                             WasmInstanceObject::kCEntryStubOffset));
+                             WasmInstanceObject::kIsolateRootOffset));
+    auto centry_id =
+        Builtins::kCEntry_Return1_DontSaveFPRegs_ArgvOnStack_NoBuiltinExit;
+    __ mov(ecx, MemOperand(ecx, IsolateData::builtin_slot_offset(centry_id)));
     // Initialize the JavaScript context with 0. CEntry will use it to
     // set the current context on the isolate.
     __ Move(kContextRegister, Smi::zero());

src/builtins/x64/builtins-x64.cc

@@ -2663,9 +2663,12 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
     // Push the function index as second argument.
     __ Push(r11);
     // Load the correct CEntry builtin from the instance object.
+    __ movq(rcx, FieldOperand(kWasmInstanceRegister,
+                              WasmInstanceObject::kIsolateRootOffset));
+    auto centry_id =
+        Builtins::kCEntry_Return1_DontSaveFPRegs_ArgvOnStack_NoBuiltinExit;
     __ LoadTaggedPointerField(
-        rcx, FieldOperand(kWasmInstanceRegister,
-                          WasmInstanceObject::kCEntryStubOffset));
+        rcx, MemOperand(rcx, IsolateData::builtin_slot_offset(centry_id)));
     // Initialize the JavaScript context with 0. CEntry will use it to
     // set the current context on the isolate.
     __ Move(kContextRegister, Smi::zero());

src/compiler/wasm-compiler.cc

@@ -3326,11 +3326,14 @@ Node* WasmGraphBuilder::BuildCallToRuntimeWithContext(
   auto call_descriptor = Linkage::GetRuntimeCallDescriptor(
       mcgraph()->zone(), f, fun->nargs, Operator::kNoProperties,
       CallDescriptor::kNoFlags);
+  Node* isolate_root = LOAD_INSTANCE_FIELD(IsolateRoot, MachineType::Pointer());
   // The CEntryStub is loaded from the instance_node so that generated code is
   // Isolate independent. At the moment this is only done for CEntryStub(1).
   DCHECK_EQ(1, fun->result_size);
-  Node* centry_stub = LOAD_INSTANCE_FIELD(
-      CEntryStub, MachineType::TypeCompressedTaggedPointer());
+  auto centry_id =
+      Builtins::kCEntry_Return1_DontSaveFPRegs_ArgvOnStack_NoBuiltinExit;
+  Node* centry_stub = LOAD_TAGGED_POINTER(
+      isolate_root, IsolateData::builtin_slot_offset(centry_id));
   // TODO(titzer): allow arbitrary number of runtime arguments
   // At the moment we only allow 5 parameters. If more parameters are needed,
   // increase this constant accordingly.

src/wasm/baseline/liftoff-compiler.cc

@@ -1631,7 +1631,13 @@ class LiftoffCompiler {
     __ TurboAssembler::Move(kContextRegister,
                             Smi::FromInt(Context::kNoContext));
     Register centry = kJavaScriptCallCodeStartRegister;
-    LOAD_TAGGED_PTR_INSTANCE_FIELD(centry, CEntryStub);
+    LOAD_INSTANCE_FIELD(centry, IsolateRoot, kSystemPointerSize);
+    // All cache registers are spilled and there are no register arguments.
+    LiftoffRegList pinned;
+    auto centry_id =
+        Builtins::kCEntry_Return1_DontSaveFPRegs_ArgvOnStack_NoBuiltinExit;
+    __ LoadTaggedPointer(centry, centry, no_reg,
+                         IsolateData::builtin_slot_offset(centry_id), pinned);
     __ CallRuntimeWithCEntry(runtime_function, centry);
     safepoint_table_builder_.DefineSafepoint(&asm_, Safepoint::kNoLazyDeopt);
   }

src/wasm/wasm-objects-inl.h

@@ -261,7 +261,6 @@ OPTIONAL_ACCESSORS(WasmInstanceObject, managed_native_allocations, Foreign,
                    kManagedNativeAllocationsOffset)
 OPTIONAL_ACCESSORS(WasmInstanceObject, exceptions_table, FixedArray,
                    kExceptionsTableOffset)
-ACCESSORS(WasmInstanceObject, centry_stub, Code, kCEntryStubOffset)
 OPTIONAL_ACCESSORS(WasmInstanceObject, wasm_exported_functions, FixedArray,
                    kWasmExportedFunctionsOffset)
 

src/wasm/wasm-objects.cc

@@ -1726,9 +1726,6 @@ Handle<WasmInstanceObject> WasmInstanceObject::New(
       isolate->factory()->NewFixedArray(num_imported_functions);
   instance->set_imported_function_refs(*imported_function_refs);
 
-  Handle<Code> centry_stub = CodeFactory::CEntry(isolate);
-  instance->set_centry_stub(*centry_stub);
-
   instance->SetRawMemory(nullptr, 0);
   instance->set_isolate_root(isolate->isolate_root());
   instance->set_stack_limit_address(

src/wasm/wasm-objects.h

@@ -444,7 +444,6 @@ class WasmInstanceObject : public JSObject {
   DECL_OPTIONAL_ACCESSORS(indirect_function_table_refs, FixedArray)
   DECL_OPTIONAL_ACCESSORS(managed_native_allocations, Foreign)
   DECL_OPTIONAL_ACCESSORS(exceptions_table, FixedArray)
-  DECL_ACCESSORS(centry_stub, Code)
   DECL_OPTIONAL_ACCESSORS(wasm_exported_functions, FixedArray)
   DECL_PRIMITIVE_ACCESSORS(memory_start, byte*)
   DECL_PRIMITIVE_ACCESSORS(memory_size, size_t)
@@ -504,7 +503,6 @@ class WasmInstanceObject : public JSObject {
   V(kIndirectFunctionTablesOffset, kTaggedSize)                           \
   V(kManagedNativeAllocationsOffset, kTaggedSize)                         \
   V(kExceptionsTableOffset, kTaggedSize)                                  \
-  V(kCEntryStubOffset, kTaggedSize)                                       \
   V(kWasmExportedFunctionsOffset, kTaggedSize)                            \
   V(kRealStackLimitAddressOffset, kSystemPointerSize)                     \
   V(kDataSegmentStartsOffset, kSystemPointerSize)                         \
@@ -544,7 +542,6 @@ class WasmInstanceObject : public JSObject {
       kIndirectFunctionTablesOffset,
       kManagedNativeAllocationsOffset,
       kExceptionsTableOffset,
-      kCEntryStubOffset,
       kWasmExportedFunctionsOffset};
 
   V8_EXPORT_PRIVATE const wasm::WasmModule* module();