Convert Linkage to use MachineSignature.

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index 30c43d6041cee2c72838afe35a93d9ebf12a1075..f415beef2f07a3590acb9e9f7c7aa998691983af 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -226,9 +226,12 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       }
       break;
     case kArchCallJSFunction: {
-      // TODO(jarin) The load of the context should be separated from the call.
       Register func = i.InputRegister(0);
-      __ movp(rsi, FieldOperand(func, JSFunction::kContextOffset));
+      if (FLAG_debug_code) {
+        // Check the function's context matches the context argument.
+        __ cmpp(rsi, FieldOperand(func, JSFunction::kContextOffset));
+        __ Assert(equal, kWrongFunctionContext);
+      }
       __ Call(FieldOperand(func, JSFunction::kCodeEntryOffset));
       AddSafepointAndDeopt(instr);
       break;
@@ -859,7 +862,7 @@ void CodeGenerator::AssembleReturn() {
     __ movq(rsp, rbp);  // Move stack pointer back to frame pointer.
     __ popq(rbp);       // Pop caller's frame pointer.
     int pop_count =
-        descriptor->IsJSFunctionCall() ? descriptor->ParameterCount() : 0;
+        descriptor->IsJSFunctionCall() ? descriptor->JSParamCount() : 0;
     __ ret(pop_count * kPointerSize);
   }
 }