[wasm] Initialize the root register for WASM tests.

src/compiler/linkage.h

 // Copyright 2014 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.
 
 #ifndef V8_COMPILER_LINKAGE_H_
 #define V8_COMPILER_LINKAGE_H_
 
 #include "src/base/flags.h"
 #include "src/compiler/frame.h"
 #include "src/compiler/operator.h"
@@ skipping 139 matching lines @@
     kPatchableCallSite = 1u << 1,
     kNeedsNopAfterCall = 1u << 2,
     kHasExceptionHandler = 1u << 3,
     kHasLocalCatchHandler = 1u << 4,
     kSupportsTailCalls = 1u << 5,
     kCanUseRoots = 1u << 6,
     // (arm64 only) native stack should be used for arguments.
     kUseNativeStack = 1u << 7,
     // (arm64 only) call instruction has to restore JSSP.
     kRestoreJSSP = 1u << 8,
+    // Causes the code generator to initialize the root register.
+    kInitializeRootRegister = 1u << 9,
     kPatchableCallSiteWithNop = kPatchableCallSite | kNeedsNopAfterCall
   };
   typedef base::Flags<Flag> Flags;
 
   CallDescriptor(Kind kind, MachineType target_type, LinkageLocation target_loc,
                  const MachineSignature* machine_sig,
                  LocationSignature* location_sig, size_t stack_param_count,
                  Operator::Properties properties,
                  RegList callee_saved_registers,
                  RegList callee_saved_fp_registers, Flags flags,
@@ skipping 46 matching lines @@
   // TODO(titzer): this should input the framestate input too.
   size_t InputCount() const { return 1 + machine_sig_->parameter_count(); }
 
   size_t FrameStateCount() const { return NeedsFrameState() ? 1 : 0; }
 
   Flags flags() const { return flags_; }
 
   bool NeedsFrameState() const { return flags() & kNeedsFrameState; }
   bool SupportsTailCalls() const { return flags() & kSupportsTailCalls; }
   bool UseNativeStack() const { return flags() & kUseNativeStack; }
+  bool InitializeRootRegister() const {
+    return flags() & kInitializeRootRegister;
+  }
 
   LinkageLocation GetReturnLocation(size_t index) const {
     return location_sig_->GetReturn(index);
   }
 
   LinkageLocation GetInputLocation(size_t index) const {
     if (index == 0) return target_loc_;
     return location_sig_->GetParam(index - 1);
   }
 
@@ skipping 84 matching lines @@
       Isolate* isolate, Zone* zone, const CallInterfaceDescriptor& descriptor,
       int stack_parameter_count, CallDescriptor::Flags flags,
       Operator::Properties properties = Operator::kNoProperties,
       MachineType return_type = MachineType::AnyTagged(),
       size_t return_count = 1);
 
   // Creates a call descriptor for simplified C calls that is appropriate
   // for the host platform. This simplified calling convention only supports
   // integers and pointers of one word size each, i.e. no floating point,
   // structs, pointers to members, etc.
-  static CallDescriptor* GetSimplifiedCDescriptor(Zone* zone,
-                                                  const MachineSignature* sig);
+  static CallDescriptor* GetSimplifiedCDescriptor(
+      Zone* zone, const MachineSignature* sig,
+      bool set_initialize_root_flag = false);
 
   // Creates a call descriptor for interpreter handler code stubs. These are not
   // intended to be called directly but are instead dispatched to by the
   // interpreter.
   static CallDescriptor* GetInterpreterDispatchDescriptor(Zone* zone);
 
   // Get the location of an (incoming) parameter to this function.
   LinkageLocation GetParameterLocation(int index) const {
     return incoming_->GetInputLocation(index + 1);  // + 1 to skip target.
   }
@@ skipping 55 matching lines @@
   CallDescriptor* const incoming_;
 
   DISALLOW_COPY_AND_ASSIGN(Linkage);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LINKAGE_H_