[turbofan] Add basic support for calling to (a subset of) C functions.

src/compiler/code-generator-impl.h

 // Copyright 2013 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_CODE_GENERATOR_IMPL_H_
 #define V8_COMPILER_CODE_GENERATOR_IMPL_H_
 
 #include "src/code-stubs.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/instruction.h"
@@ skipping 39 matching lines @@
   }
 
   uint8_t InputInt5(size_t index) {
     return static_cast<uint8_t>(InputInt32(index) & 0x1F);
   }
 
   uint8_t InputInt6(size_t index) {
     return static_cast<uint8_t>(InputInt32(index) & 0x3F);
   }
 
+  ExternalReference InputExternalReference(size_t index) {
+    return ToExternalReference(instr_->InputAt(index));
+  }
+
   Handle<HeapObject> InputHeapObject(size_t index) {
     return ToHeapObject(instr_->InputAt(index));
   }
 
   Label* InputLabel(size_t index) { return ToLabel(instr_->InputAt(index)); }
 
   RpoNumber InputRpo(size_t index) {
     return ToRpoNumber(instr_->InputAt(index));
   }
 
@@ skipping 31 matching lines @@
   Constant ToConstant(InstructionOperand* op) {
     if (op->IsImmediate()) {
       return gen_->code()->GetImmediate(ImmediateOperand::cast(op));
     }
     return gen_->code()->GetConstant(
         ConstantOperand::cast(op)->virtual_register());
   }
 
   double ToDouble(InstructionOperand* op) { return ToConstant(op).ToFloat64(); }
 
+  ExternalReference ToExternalReference(InstructionOperand* op) {
+    return ToConstant(op).ToExternalReference();
+  }
+
   Handle<HeapObject> ToHeapObject(InstructionOperand* op) {
     return ToConstant(op).ToHeapObject();
   }
 
   Frame* frame() const { return gen_->frame(); }
   Isolate* isolate() const { return gen_->isolate(); }
   Linkage* linkage() const { return gen_->linkage(); }
 
  protected:
   CodeGenerator* gen_;
@@ skipping 30 matching lines @@
 #elif V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X64
   masm->ud2();
 #endif
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CODE_GENERATOR_IMPL_H