[Nios2] final infrastructure to provide compilation of a return from …

…a function

This patch includes all missing functionality needed to provide first
compilation of a simple program that just returns from a function.
I've added a test case that checks for "ret" instruction printed in assembly
output.

Patch by Andrei Grischenko (andrei.l.grischenko@intel.com)
Differential revision: https://reviews.llvm.org/D39688

llvm-svn: 320035

llvm/lib/Target/Nios2/CMakeLists.txt

@@ -4,7 +4,10 @@ set(LLVM_TARGET_DEFINITIONS Nios2.td)
 #your hand code C++ files.
 #Nios2GenRegisterInfo.inc came from Nios2RegisterInfo.td, Nios2GenInstrInfo.inc
 #came from Nios2InstrInfo.td.
+tablegen(LLVM Nios2GenAsmWriter.inc -gen-asm-writer)
+tablegen(LLVM Nios2GenDAGISel.inc -gen-dag-isel)
 tablegen(LLVM Nios2GenRegisterInfo.inc -gen-register-info)
+tablegen(LLVM Nios2GenCallingConv.inc -gen-callingconv)
 tablegen(LLVM Nios2GenInstrInfo.inc -gen-instr-info)
 tablegen(LLVM Nios2GenSubtargetInfo.inc -gen-subtarget)
 
@@ -13,13 +16,20 @@ add_public_tablegen_target(Nios2CommonTableGen)
 
 #Nios2CodeGen should match with LLVMBuild.txt Nios2CodeGen
 add_llvm_target(Nios2CodeGen
- Nios2InstrInfo.cpp
+ Nios2AsmPrinter.cpp
  Nios2FrameLowering.cpp
+ Nios2InstrInfo.cpp
+ Nios2ISelDAGToDAG.cpp
+ Nios2ISelLowering.cpp
+ Nios2MachineFunction.cpp
+ Nios2MCInstLower.cpp
  Nios2RegisterInfo.cpp
  Nios2Subtarget.cpp
  Nios2TargetMachine.cpp
+ Nios2TargetObjectFile.cpp
  )
 
-#Should match with "subdirectories =  MCTargetDesc TargetInfo" in LLVMBuild.txt
-add_subdirectory(TargetInfo)
+#Should match with "subdirectories =  InstPrinter MCTargetDesc TargetInfo" in LLVMBuild.txt
+add_subdirectory(InstPrinter)
 add_subdirectory(MCTargetDesc)
+add_subdirectory(TargetInfo)

llvm/lib/Target/Nios2/InstPrinter/CMakeLists.txt

@@ -0,0 +1 @@
+add_llvm_library(LLVMNios2AsmPrinter Nios2InstPrinter.cpp)

llvm/lib/Target/Nios2/InstPrinter/LLVMBuild.txt

@@ -0,0 +1,23 @@
+;===- ./lib/Target/Nios2/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 = Nios2AsmPrinter
+parent = Nios2
+required_libraries = MC Support
+add_to_library_groups = Nios2

llvm/lib/Target/Nios2/InstPrinter/Nios2InstPrinter.cpp

@@ -0,0 +1,66 @@
+//===-- Nios2InstPrinter.cpp - Convert Nios2 MCInst to assembly 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 Nios2 MCInst to a .s file.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Nios2InstPrinter.h"
+
+#include "Nios2InstrInfo.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "asm-printer"
+
+#define PRINT_ALIAS_INSTR
+#include "Nios2GenAsmWriter.inc"
+
+void Nios2InstPrinter::printRegName(raw_ostream &OS, unsigned RegNo) const {
+  OS << getRegisterName(RegNo);
+}
+
+void Nios2InstPrinter::printInst(const MCInst *MI, raw_ostream &O,
+                                 StringRef Annot, const MCSubtargetInfo &STI) {
+  // Try to print any aliases first.
+  if (!printAliasInstr(MI, STI, O))
+    printInstruction(MI, STI, O);
+  printAnnotation(O, Annot);
+}
+
+void Nios2InstPrinter::printOperand(const MCInst *MI, int OpNo,
+                                    const MCSubtargetInfo &STI,
+                                    raw_ostream &O) {
+  const MCOperand &Op = MI->getOperand(OpNo);
+  if (Op.isReg()) {
+    printRegName(O, Op.getReg());
+    return;
+  }
+
+  if (Op.isImm()) {
+    O << Op.getImm();
+    return;
+  }
+
+  assert(Op.isExpr() && "unknown operand kind in printOperand");
+  Op.getExpr()->print(O, &MAI, true);
+}
+
+void Nios2InstPrinter::printMemOperand(const MCInst *MI, int opNum,
+                                       const MCSubtargetInfo &STI,
+                                       raw_ostream &O, const char *Modifier) {
+  // Load/Store memory operands -- imm($reg)
+  printOperand(MI, opNum + 1, STI, O);
+  O << "(";
+  printOperand(MI, opNum, STI, O);
+  O << ")";
+}

llvm/lib/Target/Nios2/InstPrinter/Nios2InstPrinter.h

@@ -0,0 +1,49 @@
+//= Nios2InstPrinter.h - Convert Nios2 MCInst to assembly 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 Nios2 MCInst to a .s file.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_NIOS2_INSTPRINTER_NIOS2INSTPRINTER_H
+#define LLVM_LIB_TARGET_NIOS2_INSTPRINTER_NIOS2INSTPRINTER_H
+
+#include "llvm/MC/MCInstPrinter.h"
+
+namespace llvm {
+
+class Nios2InstPrinter : public MCInstPrinter {
+public:
+  Nios2InstPrinter(const MCAsmInfo &MAI, const MCInstrInfo &MII,
+                   const MCRegisterInfo &MRI)
+      : MCInstPrinter(MAI, MII, MRI) {}
+
+  void printRegName(raw_ostream &OS, unsigned RegNo) const override;
+  void printInst(const MCInst *MI, raw_ostream &O, StringRef Annot,
+                 const MCSubtargetInfo &STI) override;
+
+  // Autogenerated by tblgen.
+  void printInstruction(const MCInst *MI, const MCSubtargetInfo &STI,
+                        raw_ostream &O);
+  static const char *getRegisterName(unsigned RegNo);
+
+  bool printAliasInstr(const MCInst *MI, const MCSubtargetInfo &STI,
+                       raw_ostream &O);
+
+  void printCustomAliasOperand(const MCInst *MI, unsigned OpIdx,
+                               unsigned PrintMethodIdx,
+                               const MCSubtargetInfo &STI, raw_ostream &O);
+  void printOperand(const MCInst *MI, int opNum, const MCSubtargetInfo &STI,
+                    raw_ostream &OS);
+  void printMemOperand(const MCInst *MI, int opNum, const MCSubtargetInfo &STI,
+                       raw_ostream &OS, const char *Modifier = nullptr);
+};
+} // end namespace llvm
+
+#endif

llvm/lib/Target/Nios2/LLVMBuild.txt

@@ -19,6 +19,7 @@
 
 [common]
 subdirectories =
+    InstPrinter 
     MCTargetDesc
     TargetInfo
 
@@ -33,6 +34,7 @@ name = Nios2
 parent = Target
 #Whether this target defines an assembly parser, assembly printer, disassembler
 #, and supports JIT compilation.They are optional.
+has_asmprinter = 1
 
 [component_1]
 #component_1 is a Library type and name is Nios2CodeGen.After build it will
@@ -46,12 +48,14 @@ parent = Nios2
 #dependencies for this component.When tools are built, the build system will
 #include the transitive closure of all required_libraries for the components
 #the tool needs.
-required_libraries = CodeGen
+required_libraries = AsmPrinter
+                     CodeGen
                      Core
                      GlobalISel
                      MC
                      Nios2Desc
                      Nios2Info
+                     SelectionDAG
                      Support
                      Target
 #end of required_libraries

llvm/lib/Target/Nios2/MCTargetDesc/CMakeLists.txt

@@ -1,2 +1,9 @@
 #MCTargetDesc / CMakeLists.txt
-add_llvm_library(LLVMNios2Desc Nios2MCTargetDesc.cpp)
+add_llvm_library(LLVMNios2Desc
+                 Nios2AsmBackend.cpp
+                 Nios2ELFObjectWriter.cpp
+                 Nios2MCAsmInfo.cpp
+                 Nios2MCExpr.cpp
+                 Nios2MCTargetDesc.cpp
+                 Nios2TargetStreamer.cpp)
+

llvm/lib/Target/Nios2/MCTargetDesc/LLVMBuild.txt

@@ -19,7 +19,8 @@
 type = Library
 name = Nios2Desc
 parent = Nios2
-required_libraries = MC 
-                     Nios2Info 
+required_libraries = MC
+                     Nios2AsmPrinter
+                     Nios2Info
                      Support
 add_to_library_groups = Nios2

llvm/lib/Target/Nios2/MCTargetDesc/Nios2AsmBackend.cpp

@@ -0,0 +1,131 @@
+//===-- Nios2AsmBackend.cpp - Nios2 Asm Backend  --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Nios2AsmBackend class.
+//
+//===----------------------------------------------------------------------===//
+//
+
+#include "MCTargetDesc/Nios2AsmBackend.h"
+#include "MCTargetDesc/Nios2FixupKinds.h"
+#include "MCTargetDesc/Nios2MCTargetDesc.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+
+using namespace llvm;
+
+// Prepare value for the target space for it
+static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value) {
+
+  unsigned Kind = Fixup.getKind();
+
+  // Add/subtract and shift
+  switch (Kind) {
+  default:
+    return 0;
+  case Nios2::fixup_Nios2_LO16:
+    break;
+  case Nios2::fixup_Nios2_HI16:
+    // Get the higher 16-bits. Also add 1 if bit 15 is 1.
+    Value = ((Value + 0x8000) >> 16) & 0xffff;
+    break;
+  }
+
+  return Value;
+}
+
+// Calculate index for Nios2 specific little endian byte order
+static unsigned calculateLEIndex(unsigned i) {
+  assert(i <= 3 && "Index out of range!");
+
+  return (1 - i / 2) * 2 + i % 2;
+}
+
+/// ApplyFixup - Apply the \p Value for given \p Fixup into the provided
+/// data fragment, at the offset specified by the fixup and following the
+/// fixup kind as appropriate.
+void Nios2AsmBackend::applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
+                                 const MCValue &Target,
+                                 MutableArrayRef<char> Data, uint64_t Value,
+                                 bool IsResolved) const {
+  MCFixupKind Kind = Fixup.getKind();
+  Value = adjustFixupValue(Fixup, Value);
+
+  if (!Value)
+    return; // Doesn't change encoding.
+
+  // Where do we start in the object
+  unsigned Offset = Fixup.getOffset();
+  // Number of bytes we need to fixup
+  unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
+  // Grab current value, if any, from bits.
+  uint64_t CurVal = 0;
+
+  for (unsigned i = 0; i != NumBytes; ++i) {
+    unsigned Idx = calculateLEIndex(i);
+    CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i * 8);
+  }
+
+  uint64_t Mask = ((uint64_t)(-1) >> (64 - getFixupKindInfo(Kind).TargetSize));
+  CurVal |= Value & Mask;
+
+  // Write out the fixed up bytes back to the code/data bits.
+  for (unsigned i = 0; i != NumBytes; ++i) {
+    unsigned Idx = calculateLEIndex(i);
+    Data[Offset + Idx] = (uint8_t)((CurVal >> (i * 8)) & 0xff);
+  }
+}
+
+Optional<MCFixupKind> Nios2AsmBackend::getFixupKind(StringRef Name) const {
+  return StringSwitch<Optional<MCFixupKind>>(Name)
+      .Case("R_NIOS2_NONE", (MCFixupKind)Nios2::fixup_Nios2_32)
+      .Case("R_NIOS2_32", FK_Data_4)
+      .Default(MCAsmBackend::getFixupKind(Name));
+}
+
+//@getFixupKindInfo {
+const MCFixupKindInfo &
+Nios2AsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
+  const static MCFixupKindInfo Infos[Nios2::NumTargetFixupKinds] = {
+      // This table *must* be in same the order of fixup_* kinds in
+      // Nios2FixupKinds.h.
+      //
+      // name                        offset  bits  flags
+      {"fixup_Nios2_32", 0, 32, 0},
+      {"fixup_Nios2_HI16", 0, 16, 0},
+      {"fixup_Nios2_LO16", 0, 16, 0}};
+
+  if (Kind < FirstTargetFixupKind)
+    return MCAsmBackend::getFixupKindInfo(Kind);
+
+  assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
+         "Invalid kind!");
+  return Infos[Kind - FirstTargetFixupKind];
+}
+
+std::unique_ptr<MCObjectWriter>
+Nios2AsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
+  return createNios2ELFObjectWriter(OS,
+                                    MCELFObjectTargetWriter::getOSABI(OSType));
+}
+
+bool Nios2AsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
+  return true;
+}
+
+// MCAsmBackend
+MCAsmBackend *llvm::createNios2AsmBackend(const Target &T,
+                                          const MCRegisterInfo &MRI,
+                                          const Triple &TT, StringRef CPU,
+                                          const MCTargetOptions &Options) {
+
+  return new Nios2AsmBackend(T, TT.getOS());
+}