[wasm] Reflect unavailability of root register in linkage

The root register is not available in JS-to-Wasm functions, and
this was not reflected in the linkage. Similarily, it is not
available in C-to-Wasm functions.

Change-Id: I2dbfd06ef99d6f9b9940e9489f563441d9ebfabd
Bug: v8:6666
Reviewed-on: https://chromium-review.googlesource.com/1256766
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56346}

src/compiler/code-assembler.cc

@@ -61,10 +61,11 @@ CodeAssemblerState::CodeAssemblerState(Isolate* isolate, Zone* zone,
                                        int32_t builtin_index)
     : CodeAssemblerState(
           isolate, zone,
-          Linkage::GetJSCallDescriptor(zone, false, parameter_count,
-                                       kind == Code::BUILTIN
-                                           ? CallDescriptor::kPushArgumentCount
-                                           : CallDescriptor::kNoFlags),
+          Linkage::GetJSCallDescriptor(
+              zone, false, parameter_count,
+              (kind == Code::BUILTIN ? CallDescriptor::kPushArgumentCount
+                                     : CallDescriptor::kNoFlags) |
+                  CallDescriptor::kCanUseRoots),
           kind, name, poisoning_level, 0, builtin_index) {}
 
 CodeAssemblerState::CodeAssemblerState(Isolate* isolate, Zone* zone,

src/compiler/js-typed-lowering.cc

@@ -1687,7 +1687,8 @@ Reduction JSTypedLowering::ReduceJSCall(Node* node) {
       node->InsertInput(graph()->zone(), arity + 3, argument_count);
       NodeProperties::ChangeOp(node,
                                common()->Call(Linkage::GetJSCallDescriptor(
-                                   graph()->zone(), false, 1 + arity, flags)));
+                                   graph()->zone(), false, 1 + arity,
+                                   flags | CallDescriptor::kCanUseRoots)));
     }
     return Changed(node);
   }

src/compiler/linkage.cc

@@ -143,7 +143,7 @@ CallDescriptor* Linkage::ComputeIncoming(Zone* zone,
     SharedFunctionInfo* shared = info->closure()->shared();
     return GetJSCallDescriptor(zone, info->is_osr(),
                                1 + shared->internal_formal_parameter_count(),
-                               CallDescriptor::kNoFlags);
+                               CallDescriptor::kCanUseRoots);
   }
   return nullptr;  // TODO(titzer): ?
 }
@@ -331,8 +331,7 @@ CallDescriptor* Linkage::GetJSCallDescriptor(Zone* zone, bool is_osr,
       Operator::kNoProperties,          // properties
       kNoCalleeSaved,                   // callee-saved
       kNoCalleeSaved,                   // callee-saved fp
-      CallDescriptor::kCanUseRoots |    // flags
-          flags,                        // flags
+      flags,                            // flags
       "js-call");
 }
 

test/unittests/compiler/instruction-selector-unittest.cc

@@ -365,7 +365,8 @@ TARGET_TEST_F(InstructionSelectorTest, CallJSFunctionWithDeopt) {
   ZoneVector<MachineType> empty_types(zone());
 
   auto call_descriptor = Linkage::GetJSCallDescriptor(
-      zone(), false, 1, CallDescriptor::kNeedsFrameState);
+      zone(), false, 1,
+      CallDescriptor::kNeedsFrameState | CallDescriptor::kCanUseRoots);
 
   // Build frame state for the state before the call.
   Node* parameters = m.AddNode(