[turbofan] Enforce that C calls do not use floating point params.

src/compiler/c-linkage.cc

 // Copyright 2015 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.
 
 #include "src/assembler.h"
 #include "src/macro-assembler.h"
 
 #include "src/compiler/linkage.h"
 
 #include "src/zone.h"
@@ skipping 118 matching lines @@
 #define UNSUPPORTED_C_LINKAGE 1
 #endif
 }  // namespace
 
 
 // General code uses the above configuration data.
 CallDescriptor* Linkage::GetSimplifiedCDescriptor(
     Zone* zone, const MachineSignature* msig, bool set_initialize_root_flag) {
   LocationSignature::Builder locations(zone, msig->return_count(),
                                        msig->parameter_count());
-#if 0  // TODO(titzer): instruction selector tests break here.
   // Check the types of the signature.
   // Currently no floating point parameters or returns are allowed because
   // on x87 and ia32, the FP top of stack is involved.
-
   for (size_t i = 0; i < msig->return_count(); i++) {
-    MachineType type = RepresentationOf(msig->GetReturn(i));
-    CHECK(type != kRepFloat32 && type != kRepFloat64);
+    MachineRepresentation rep = msig->GetReturn(i).representation();
+    CHECK(rep != MachineRepresentation::kFloat32 &&

[Benedikt Meurer, 2016/02/15 12:45:32]

Nit: two separate CHECKs instead of combining with &&

+          rep != MachineRepresentation::kFloat64);
   }
   for (size_t i = 0; i < msig->parameter_count(); i++) {
-    MachineType type = RepresentationOf(msig->GetParam(i));
-    CHECK(type != kRepFloat32 && type != kRepFloat64);
+    MachineRepresentation rep = msig->GetParam(i).representation();
+    CHECK(rep != MachineRepresentation::kFloat32 &&

[Benedikt Meurer, 2016/02/15 12:45:32]

Nit: two separate CHECKs instead of combining with &&

+          rep != MachineRepresentation::kFloat64);
   }
-#endif
 
 #ifdef UNSUPPORTED_C_LINKAGE
   // This method should not be called on unknown architectures.
   V8_Fatal(__FILE__, __LINE__,
            "requested C call descriptor on unsupported architecture");
   return nullptr;
 #endif
 
   // Add return location(s).
   CHECK(locations.return_count_ <= 2);
@@ skipping 59 matching lines @@
       kCalleeSaveFPRegisters,        // callee-saved fp regs
       set_initialize_root_flag ?     // flags
           CallDescriptor::kInitializeRootRegister
                                : CallDescriptor::kNoFlags,
       "c-call");
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8