1 files changed, 337 insertions, 0 deletions
diff --git a/llvm/lib/MC/MCWinCOFFStreamer.cpp b/llvm/lib/MC/MCWinCOFFStreamer.cpp
new file mode 100644
index 000000000000..c5a21312140b
--- /dev/null
+++ b/llvm/lib/MC/MCWinCOFFStreamer.cpp
@@ -0,0 +1,337 @@
+//===- llvm/MC/MCWinCOFFStreamer.cpp --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains an implementation of a Windows COFF object file streamer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/BinaryFormat/COFF.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCFixup.h"
+#include "llvm/MC/MCFragment.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCObjectStreamer.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCSymbolCOFF.h"
+#include "llvm/MC/MCWinCOFFStreamer.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/SMLoc.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "WinCOFFStreamer"
+
+MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context,
+                                     std::unique_ptr<MCAsmBackend> MAB,
+                                     std::unique_ptr<MCCodeEmitter> CE,
+                                     std::unique_ptr<MCObjectWriter> OW)
+    : MCObjectStreamer(Context, std::move(MAB), std::move(OW), std::move(CE)),
+      CurSymbol(nullptr) {}
+
+void MCWinCOFFStreamer::EmitInstToData(const MCInst &Inst,
+                                       const MCSubtargetInfo &STI) {
+  MCDataFragment *DF = getOrCreateDataFragment();
+
+  SmallVector<MCFixup, 4> Fixups;
+  SmallString<256> Code;
+  raw_svector_ostream VecOS(Code);
+  getAssembler().getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
+
+  // 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->getFixups().push_back(Fixups[i]);
+  }
+  DF->setHasInstructions(STI);
+  DF->getContents().append(Code.begin(), Code.end());
+}
+
+void MCWinCOFFStreamer::InitSections(bool NoExecStack) {
+  // FIXME: this is identical to the ELF one.
+  // This emulates the same behavior of GNU as. This makes it easier
+  // to compare the output as the major sections are in the same order.
+  SwitchSection(getContext().getObjectFileInfo()->getTextSection());
+  EmitCodeAlignment(4);
+
+  SwitchSection(getContext().getObjectFileInfo()->getDataSection());
+  EmitCodeAlignment(4);
+
+  SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
+  EmitCodeAlignment(4);
+
+  SwitchSection(getContext().getObjectFileInfo()->getTextSection());
+}
+
+void MCWinCOFFStreamer::EmitLabel(MCSymbol *S, SMLoc Loc) {
+  auto *Symbol = cast<MCSymbolCOFF>(S);
+  MCObjectStreamer::EmitLabel(Symbol, Loc);
+}
+
+void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
+  // Let the target do whatever target specific stuff it needs to do.
+  getAssembler().getBackend().handleAssemblerFlag(Flag);
+
+  switch (Flag) {
+  // None of these require COFF specific handling.
+  case MCAF_SyntaxUnified:
+  case MCAF_Code16:
+  case MCAF_Code32:
+  case MCAF_Code64:
+    break;
+  case MCAF_SubsectionsViaSymbols:
+    llvm_unreachable("COFF doesn't support .subsections_via_symbols");
+  }
+}
+
+void MCWinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
+  llvm_unreachable("not implemented");
+}
+
+bool MCWinCOFFStreamer::EmitSymbolAttribute(MCSymbol *S,
+                                            MCSymbolAttr Attribute) {
+  auto *Symbol = cast<MCSymbolCOFF>(S);
+  getAssembler().registerSymbol(*Symbol);
+
+  switch (Attribute) {
+  default: return false;
+  case MCSA_WeakReference:
+  case MCSA_Weak:
+    Symbol->setIsWeakExternal();
+    Symbol->setExternal(true);
+    break;
+  case MCSA_Global:
+    Symbol->setExternal(true);
+    break;
+  case MCSA_AltEntry:
+    llvm_unreachable("COFF doesn't support the .alt_entry attribute");
+  }
+
+  return true;
+}
+
+void MCWinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
+  llvm_unreachable("not implemented");
+}
+
+void MCWinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *S) {
+  auto *Symbol = cast<MCSymbolCOFF>(S);
+  if (CurSymbol)
+    Error("starting a new symbol definition without completing the "
+          "previous one");
+  CurSymbol = Symbol;
+}
+
+void MCWinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
+  if (!CurSymbol) {
+    Error("storage class specified outside of symbol definition");
+    return;
+  }
+
+  if (StorageClass & ~COFF::SSC_Invalid) {
+    Error("storage class value '" + Twine(StorageClass) +
+               "' out of range");
+    return;
+  }
+
+  getAssembler().registerSymbol(*CurSymbol);
+  cast<MCSymbolCOFF>(CurSymbol)->setClass((uint16_t)StorageClass);
+}
+
+void MCWinCOFFStreamer::EmitCOFFSymbolType(int Type) {
+  if (!CurSymbol) {
+    Error("symbol type specified outside of a symbol definition");
+    return;
+  }
+
+  if (Type & ~0xffff) {
+    Error("type value '" + Twine(Type) + "' out of range");
+    return;
+  }
+
+  getAssembler().registerSymbol(*CurSymbol);
+  cast<MCSymbolCOFF>(CurSymbol)->setType((uint16_t)Type);
+}
+
+void MCWinCOFFStreamer::EndCOFFSymbolDef() {
+  if (!CurSymbol)
+    Error("ending symbol definition without starting one");
+  CurSymbol = nullptr;
+}
+
+void MCWinCOFFStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {
+  // SafeSEH is a feature specific to 32-bit x86.  It does not exist (and is
+  // unnecessary) on all platforms which use table-based exception dispatch.
+  if (getContext().getObjectFileInfo()->getTargetTriple().getArch() !=
+      Triple::x86)
+    return;
+
+  const MCSymbolCOFF *CSymbol = cast<MCSymbolCOFF>(Symbol);
+  if (CSymbol->isSafeSEH())
+    return;
+
+  MCSection *SXData = getContext().getObjectFileInfo()->getSXDataSection();
+  getAssembler().registerSection(*SXData);
+  if (SXData->getAlignment() < 4)
+    SXData->setAlignment(Align(4));
+
+  new MCSymbolIdFragment(Symbol, SXData);
+
+  getAssembler().registerSymbol(*Symbol);
+  CSymbol->setIsSafeSEH();
+
+  // The Microsoft linker requires that the symbol type of a handler be
+  // function. Go ahead and oblige it here.
+  CSymbol->setType(COFF::IMAGE_SYM_DTYPE_FUNCTION
+                   << COFF::SCT_COMPLEX_TYPE_SHIFT);
+}
+
+void MCWinCOFFStreamer::EmitCOFFSymbolIndex(MCSymbol const *Symbol) {
+  MCSection *Sec = getCurrentSectionOnly();
+  getAssembler().registerSection(*Sec);
+  if (Sec->getAlignment() < 4)
+    Sec->setAlignment(Align(4));
+
+  new MCSymbolIdFragment(Symbol, getCurrentSectionOnly());
+
+  getAssembler().registerSymbol(*Symbol);
+}
+
+void MCWinCOFFStreamer::EmitCOFFSectionIndex(const MCSymbol *Symbol) {
+  visitUsedSymbol(*Symbol);
+  MCDataFragment *DF = getOrCreateDataFragment();
+  const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
+  MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_2);
+  DF->getFixups().push_back(Fixup);
+  DF->getContents().resize(DF->getContents().size() + 2, 0);
+}
+
+void MCWinCOFFStreamer::EmitCOFFSecRel32(const MCSymbol *Symbol,
+                                         uint64_t Offset) {
+  visitUsedSymbol(*Symbol);
+  MCDataFragment *DF = getOrCreateDataFragment();
+  // Create Symbol A for the relocation relative reference.
+  const MCExpr *MCE = MCSymbolRefExpr::create(Symbol, getContext());
+  // Add the constant offset, if given.
+  if (Offset)
+    MCE = MCBinaryExpr::createAdd(
+        MCE, MCConstantExpr::create(Offset, getContext()), getContext());
+  // Build the secrel32 relocation.
+  MCFixup Fixup = MCFixup::create(DF->getContents().size(), MCE, FK_SecRel_4);
+  // Record the relocation.
+  DF->getFixups().push_back(Fixup);
+  // Emit 4 bytes (zeros) to the object file.
+  DF->getContents().resize(DF->getContents().size() + 4, 0);
+}
+
+void MCWinCOFFStreamer::EmitCOFFImgRel32(const MCSymbol *Symbol,
+                                         int64_t Offset) {
+  visitUsedSymbol(*Symbol);
+  MCDataFragment *DF = getOrCreateDataFragment();
+  // Create Symbol A for the relocation relative reference.
+  const MCExpr *MCE = MCSymbolRefExpr::create(
+      Symbol, MCSymbolRefExpr::VK_COFF_IMGREL32, getContext());
+  // Add the constant offset, if given.
+  if (Offset)
+    MCE = MCBinaryExpr::createAdd(
+        MCE, MCConstantExpr::create(Offset, getContext()), getContext());
+  // Build the imgrel relocation.
+  MCFixup Fixup = MCFixup::create(DF->getContents().size(), MCE, FK_Data_4);
+  // Record the relocation.
+  DF->getFixups().push_back(Fixup);
+  // Emit 4 bytes (zeros) to the object file.
+  DF->getContents().resize(DF->getContents().size() + 4, 0);
+}
+
+void MCWinCOFFStreamer::EmitCommonSymbol(MCSymbol *S, uint64_t Size,
+                                         unsigned ByteAlignment) {
+  auto *Symbol = cast<MCSymbolCOFF>(S);
+
+  const Triple &T = getContext().getObjectFileInfo()->getTargetTriple();
+  if (T.isWindowsMSVCEnvironment()) {
+    if (ByteAlignment > 32)
+      report_fatal_error("alignment is limited to 32-bytes");
+
+    // Round size up to alignment so that we will honor the alignment request.
+    Size = std::max(Size, static_cast<uint64_t>(ByteAlignment));
+  }
+
+  getAssembler().registerSymbol(*Symbol);
+  Symbol->setExternal(true);
+  Symbol->setCommon(Size, ByteAlignment);
+
+  if (!T.isWindowsMSVCEnvironment() && ByteAlignment > 1) {
+    SmallString<128> Directive;
+    raw_svector_ostream OS(Directive);
+    const MCObjectFileInfo *MFI = getContext().getObjectFileInfo();
+
+    OS << " -aligncomm:\"" << Symbol->getName() << "\","
+       << Log2_32_Ceil(ByteAlignment);
+
+    PushSection();
+    SwitchSection(MFI->getDrectveSection());
+    EmitBytes(Directive);
+    PopSection();
+  }
+}
+
+void MCWinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *S, uint64_t Size,
+                                              unsigned ByteAlignment) {
+  auto *Symbol = cast<MCSymbolCOFF>(S);
+
+  MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
+  PushSection();
+  SwitchSection(Section);
+  EmitValueToAlignment(ByteAlignment, 0, 1, 0);
+  EmitLabel(Symbol);
+  Symbol->setExternal(false);
+  EmitZeros(Size);
+  PopSection();
+}
+
+void MCWinCOFFStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
+                                     uint64_t Size, unsigned ByteAlignment,
+                                     SMLoc Loc) {
+  llvm_unreachable("not implemented");
+}
+
+void MCWinCOFFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
+                                       uint64_t Size, unsigned ByteAlignment) {
+  llvm_unreachable("not implemented");
+}
+
+// TODO: Implement this if you want to emit .comment section in COFF obj files.
+void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
+  llvm_unreachable("not implemented");
+}
+
+void MCWinCOFFStreamer::EmitWinEHHandlerData(SMLoc Loc) {
+  llvm_unreachable("not implemented");
+}
+
+void MCWinCOFFStreamer::FinishImpl() {
+  MCObjectStreamer::FinishImpl();
+}
+
+void MCWinCOFFStreamer::Error(const Twine &Msg) const {
+  getContext().reportError(SMLoc(), Msg);
+}