[RISCV] Add RISCVInstPrinter and basic MC assembler tests

With the addition of RISCVInstPrinter, it is now possible to test the basic 
operation of the RISCV MC layer.

Differential Revision: https://reviews.llvm.org/D23564

llvm-svn: 310917
diff --git a/llvm/lib/Target/RISCV/InstPrinter/CMakeLists.txt b/llvm/lib/Target/RISCV/InstPrinter/CMakeLists.txt
new file mode 100644
index 0000000..7f91743
--- /dev/null
+++ b/llvm/lib/Target/RISCV/InstPrinter/CMakeLists.txt
@@ -0,0 +1,3 @@
+add_llvm_library(LLVMRISCVAsmPrinter
+  RISCVInstPrinter.cpp
+  )
diff --git a/llvm/lib/Target/RISCV/InstPrinter/LLVMBuild.txt b/llvm/lib/Target/RISCV/InstPrinter/LLVMBuild.txt
new file mode 100644
index 0000000..5f4545e
--- /dev/null
+++ b/llvm/lib/Target/RISCV/InstPrinter/LLVMBuild.txt
@@ -0,0 +1,23 @@
+;===- ./lib/Target/RISCV/InstPrinter/LLVMBuild.txt -------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = RISCVAsmPrinter
+parent = RISCV
+required_libraries = MC Support
+add_to_library_groups = RISCV
diff --git a/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp b/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp
new file mode 100644
index 0000000..23f3352c0
--- /dev/null
+++ b/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.cpp
@@ -0,0 +1,55 @@
+//===-- RISCVInstPrinter.cpp - Convert RISCV MCInst to asm syntax ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class prints an RISCV MCInst to a .s file.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVInstPrinter.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FormattedStream.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "asm-printer"
+
+// Include the auto-generated portion of the assembly writer.
+#include "RISCVGenAsmWriter.inc"
+
+void RISCVInstPrinter::printInst(const MCInst *MI, raw_ostream &O,
+                                 StringRef Annot, const MCSubtargetInfo &STI) {
+  printInstruction(MI, O);
+  printAnnotation(O, Annot);
+}
+
+void RISCVInstPrinter::printRegName(raw_ostream &O, unsigned RegNo) const {
+  O << getRegisterName(RegNo);
+}
+
+void RISCVInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
+                                  raw_ostream &O, const char *Modifier) {
+  assert((Modifier == 0 || Modifier[0] == 0) && "No modifiers supported");
+  const MCOperand &MO = MI->getOperand(OpNo);
+
+  if (MO.isReg()) {
+    printRegName(O, MO.getReg());
+    return;
+  }
+
+  if (MO.isImm()) {
+    O << MO.getImm();
+    return;
+  }
+
+  assert(MO.isExpr() && "Unknown operand kind in printOperand");
+  MO.getExpr()->print(O, &MAI);
+}
diff --git a/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.h b/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.h
new file mode 100644
index 0000000..f378c6f
--- /dev/null
+++ b/llvm/lib/Target/RISCV/InstPrinter/RISCVInstPrinter.h
@@ -0,0 +1,43 @@
+//===-- RISCVInstPrinter.h - Convert RISCV MCInst to asm syntax ---*- C++ -*--//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class prints a RISCV MCInst to a .s file.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_RISCV_INSTPRINTER_RISCVINSTPRINTER_H
+#define LLVM_LIB_TARGET_RISCV_INSTPRINTER_RISCVINSTPRINTER_H
+
+#include "MCTargetDesc/RISCVMCTargetDesc.h"
+#include "llvm/MC/MCInstPrinter.h"
+
+namespace llvm {
+class MCOperand;
+
+class RISCVInstPrinter : public MCInstPrinter {
+public:
+  RISCVInstPrinter(const MCAsmInfo &MAI, const MCInstrInfo &MII,
+                   const MCRegisterInfo &MRI)
+      : MCInstPrinter(MAI, MII, MRI) {}
+
+  void printInst(const MCInst *MI, raw_ostream &O, StringRef Annot,
+                 const MCSubtargetInfo &STI) override;
+  void printRegName(raw_ostream &O, unsigned RegNo) const override;
+
+  void printOperand(const MCInst *MI, unsigned OpNo, raw_ostream &O,
+                    const char *Modifier = nullptr);
+
+  // Autogenerated by tblgen.
+  void printInstruction(const MCInst *MI, raw_ostream &O);
+  static const char *getRegisterName(unsigned RegNo,
+                                     unsigned AltIdx = RISCV::ABIRegAltName);
+};
+}
+
+#endif