MC-JIT: Stub out "pure" streamer.

- No immediate use, but maybe someone feels like hacking on it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119510 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCStreamer.h

@@ -417,6 +417,13 @@ namespace llvm {
   /// The new streamer takes ownership of the \arg Child.
   MCStreamer *createLoggingStreamer(MCStreamer *Child, raw_ostream &OS);
 
+  /// createPureStreamer - Create a machine code streamer which will generate
+  /// "pure" MC object files, for use with MC-JIT and testing tools.
+  ///
+  /// Takes ownership of \arg TAB and \arg CE.
+  MCStreamer *createPureStreamer(MCContext &Ctx, TargetAsmBackend &TAB,
+                                 raw_ostream &OS, MCCodeEmitter *CE);
+
 } // end namespace llvm
 
 #endif

lib/MC/CMakeLists.txt

@@ -20,6 +20,7 @@ add_llvm_library(LLVMMC
   MCObjectStreamer.cpp
   MCObjectFormat.cpp
   MCObjectWriter.cpp
+  MCPureStreamer.cpp
   MCSection.cpp
   MCSectionCOFF.cpp
   MCSectionELF.cpp

lib/MC/MCPureStreamer.cpp

@@ -0,0 +1,259 @@
+//===- lib/MC/MCPureStreamer.cpp - MC "Pure" Object Output ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCObjectStreamer.h"
+// FIXME: Remove this.
+#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace llvm;
+
+namespace {
+
+class MCPureStreamer : public MCObjectStreamer {
+private:
+  virtual void EmitInstToFragment(const MCInst &Inst);
+  virtual void EmitInstToData(const MCInst &Inst);
+
+public:
+  MCPureStreamer(MCContext &Context, TargetAsmBackend &TAB,
+                 raw_ostream &OS, MCCodeEmitter *Emitter)
+    : MCObjectStreamer(Context, TAB, OS, Emitter,
+                       /*PadSectionToAlignment=*/true) {}
+
+  /// @name MCStreamer Interface
+  /// @{
+
+  virtual void InitSections();
+  virtual void EmitLabel(MCSymbol *Symbol);
+  virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
+  virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
+                            unsigned Size = 0, unsigned ByteAlignment = 0);
+  virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
+  virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace);
+  virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
+                                    unsigned ValueSize = 1,
+                                    unsigned MaxBytesToEmit = 0);
+  virtual void EmitCodeAlignment(unsigned ByteAlignment,
+                                 unsigned MaxBytesToEmit = 0);
+  virtual void EmitValueToOffset(const MCExpr *Offset,
+                                 unsigned char Value = 0);
+  virtual void Finish();
+
+
+  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
+                              uint64_t Size, unsigned ByteAlignment = 0) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                unsigned ByteAlignment) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitThumbFunc(MCSymbol *Func) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitCOFFSymbolType(int Type) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EndCOFFSymbolDef() {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitGPRel32Value(const MCExpr *Value) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual void EmitFileDirective(StringRef Filename) {
+    report_fatal_error("unsupported directive in pure streamer");
+  }
+  virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Filename) {
+    report_fatal_error("unsupported directive in pure streamer");
+    return false;
+  }
+
+  /// @}
+};
+
+} // end anonymous namespace.
+
+void MCPureStreamer::InitSections() {
+  // FIMXE: To what!?
+  SwitchSection(getContext().getMachOSection("__TEXT", "__text",
+                                    MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
+                                    0, SectionKind::getText()));
+
+}
+
+void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
+  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
+  assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
+  assert(CurSection && "Cannot emit before setting section!");
+
+  Symbol->setSection(*CurSection);
+
+  MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
+
+  // We have to create a new fragment if this is an atom defining symbol,
+  // fragments cannot span atoms.
+  if (getAssembler().isSymbolLinkerVisible(SD.getSymbol()))
+    new MCDataFragment(getCurrentSectionData());
+
+  // FIXME: This is wasteful, we don't necessarily need to create a data
+  // fragment. Instead, we should mark the symbol as pointing into the data
+  // fragment if it exists, otherwise we should just queue the label and set its
+  // fragment pointer when we emit the next fragment.
+  MCDataFragment *F = getOrCreateDataFragment();
+  assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
+  SD.setFragment(F);
+  SD.setOffset(F->getContents().size());
+}
+
+void MCPureStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
+  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
+  // MCObjectStreamer.
+  // FIXME: Lift context changes into super class.
+  getAssembler().getOrCreateSymbolData(*Symbol);
+  Symbol->setVariableValue(AddValueSymbols(Value));
+}
+
+void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
+                                  unsigned Size, unsigned ByteAlignment) {
+  report_fatal_error("not yet implemented in pure streamer");
+}
+
+void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
+  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
+  // MCObjectStreamer.
+  getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
+}
+
+void MCPureStreamer::EmitValue(const MCExpr *Value, unsigned Size,
+                               unsigned AddrSpace) {
+  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
+  // MCObjectStreamer.
+  MCDataFragment *DF = getOrCreateDataFragment();
+
+  // Avoid fixups when possible.
+  int64_t AbsValue;
+  if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue)) {
+    // FIXME: Endianness assumption.
+    for (unsigned i = 0; i != Size; ++i)
+      DF->getContents().push_back(uint8_t(AbsValue >> (i * 8)));
+  } else {
+    DF->addFixup(MCFixup::Create(DF->getContents().size(),
+                                 AddValueSymbols(Value),
+                                 MCFixup::getKindForSize(Size)));
+    DF->getContents().resize(DF->getContents().size() + Size, 0);
+  }
+}
+
+void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
+                                          int64_t Value, unsigned ValueSize,
+                                          unsigned MaxBytesToEmit) {
+  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
+  // MCObjectStreamer.
+  if (MaxBytesToEmit == 0)
+    MaxBytesToEmit = ByteAlignment;
+  new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
+                      getCurrentSectionData());
+
+  // Update the maximum alignment on the current section if necessary.
+  if (ByteAlignment > getCurrentSectionData()->getAlignment())
+    getCurrentSectionData()->setAlignment(ByteAlignment);
+}
+
+void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment,
+                                       unsigned MaxBytesToEmit) {
+  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
+  // MCObjectStreamer.
+  if (MaxBytesToEmit == 0)
+    MaxBytesToEmit = ByteAlignment;
+  MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
+                                           getCurrentSectionData());
+  F->setEmitNops(true);
+
+  // Update the maximum alignment on the current section if necessary.
+  if (ByteAlignment > getCurrentSectionData()->getAlignment())
+    getCurrentSectionData()->setAlignment(ByteAlignment);
+}
+
+void MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
+                                       unsigned char Value) {
+  new MCOrgFragment(*Offset, Value, getCurrentSectionData());
+}
+
+void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
+  MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
+
+  // Add the fixups and data.
+  //
+  // FIXME: Revisit this design decision when relaxation is done, we may be
+  // able to get away with not storing any extra data in the MCInst.
+  SmallVector<MCFixup, 4> Fixups;
+  SmallString<256> Code;
+  raw_svector_ostream VecOS(Code);
+  getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
+  VecOS.flush();
+
+  IF->getCode() = Code;
+  IF->getFixups() = Fixups;
+}
+
+void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
+  MCDataFragment *DF = getOrCreateDataFragment();
+
+  SmallVector<MCFixup, 4> Fixups;
+  SmallString<256> Code;
+  raw_svector_ostream VecOS(Code);
+  getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
+  VecOS.flush();
+
+  // Add the fixups and data.
+  for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
+    Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
+    DF->addFixup(Fixups[i]);
+  }
+  DF->getContents().append(Code.begin(), Code.end());
+}
+
+void MCPureStreamer::Finish() {
+  // FIXME: Handle DWARF tables?
+
+  this->MCObjectStreamer::Finish();
+}
+
+MCStreamer *llvm::createPureStreamer(MCContext &Context, TargetAsmBackend &TAB,
+                                     raw_ostream &OS, MCCodeEmitter *CE) {
+  return new MCPureStreamer(Context, TAB, OS, CE);
+}