[turbofan] Fix calls to computed code objects.

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1377423002

Cr-Commit-Position: refs/heads/master@{#31057}

src/compiler/ia32/code-generator-ia32.cc

@@ -308,7 +308,8 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
         __ call(code, RelocInfo::CODE_TARGET);
       } else {
         Register reg = i.InputRegister(0);
-        __ call(Operand(reg, Code::kHeaderSize - kHeapObjectTag));
+        __ add(reg, Immediate(Code::kHeaderSize - kHeapObjectTag));
+        __ call(reg);
       }
       RecordCallPosition(instr);
       break;

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

@@ -555,8 +555,8 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
         __ Call(code, RelocInfo::CODE_TARGET);
       } else {
         Register reg = i.InputRegister(0);
-        int entry = Code::kHeaderSize - kHeapObjectTag;
-        __ Call(Operand(reg, entry));
+        __ addp(reg, Immediate(Code::kHeaderSize - kHeapObjectTag));
+        __ call(reg);
       }
       RecordCallPosition(instr);
       break;

test/cctest/compiler/codegen-tester.h

@@ -52,6 +52,11 @@ class RawMachineAssemblerTester : public HandleAndZoneScope,
 
   void GenerateCode() { Generate(); }
 
+  Handle<Code> GetCode() {
+    Generate();
+    return code_.ToHandleChecked();
+  }
+
  protected:
   virtual byte* Generate() {
     if (code_.is_null()) {

test/cctest/compiler/test-run-machops.cc

@@ -5387,3 +5387,52 @@ TEST(RunBitcastInt32ToFloat32) {
     CHECK_EQ(bit_cast<int32_t>(expected), bit_cast<int32_t>(output));
   }
 }
+
+
+TEST(RunComputedCodeObject) {
+  RawMachineAssemblerTester<int32_t> a;
+  a.Return(a.Int32Constant(33));
+  CHECK_EQ(33, a.Call());
+
+  RawMachineAssemblerTester<int32_t> b;
+  b.Return(b.Int32Constant(44));
+  CHECK_EQ(44, b.Call());
+
+  RawMachineAssemblerTester<int32_t> r(kMachInt32);
+  RawMachineAssembler::Label tlabel;
+  RawMachineAssembler::Label flabel;
+  RawMachineAssembler::Label merge;
+  r.Branch(r.Parameter(0), &tlabel, &flabel);
+  r.Bind(&tlabel);
+  Node* fa = r.HeapConstant(a.GetCode());
+  r.Goto(&merge);
+  r.Bind(&flabel);
+  Node* fb = r.HeapConstant(b.GetCode());
+  r.Goto(&merge);
+  r.Bind(&merge);
+  Node* phi = r.Phi(kMachInt32, fa, fb);
+
+  // TODO(titzer): all this descriptor hackery is just to call the above
+  // functions as code objects instead of direct addresses.
+  CSignature0<int32_t> sig;
+  CallDescriptor* c = Linkage::GetSimplifiedCDescriptor(r.zone(), &sig);
+  LinkageLocation ret[] = {c->GetReturnLocation(0)};
+  Signature<LinkageLocation> loc(1, 0, ret);
+  CallDescriptor* desc = new (r.zone()) CallDescriptor(  // --
+      CallDescriptor::kCallCodeObject,                   // kind
+      kMachAnyTagged,                                    // target_type
+      c->GetInputLocation(0),                            // target_loc
+      &sig,                                              // machine_sig
+      &loc,                                              // location_sig
+      0,                                                 // stack count
+      Operator::kNoProperties,                           // properties
+      c->CalleeSavedRegisters(),                         // callee saved
+      c->CalleeSavedFPRegisters(),                       // callee saved FP
+      CallDescriptor::kNoFlags,                          // flags
+      "c-call-as-code");
+  Node* call = r.AddNode(r.common()->Call(desc), phi);
+  r.Return(call);
+
+  CHECK_EQ(33, r.Call(1));
+  CHECK_EQ(44, r.Call(0));
+}