1 files changed, 222 insertions, 0 deletions
diff --git a/llvm/lib/MC/MCCodeView.cpp b/llvm/lib/MC/MCCodeView.cpp
new file mode 100644
index 00000000000..992edd0a8bc
--- /dev/null
+++ b/llvm/lib/MC/MCCodeView.cpp
@@ -0,0 +1,222 @@
+//===- MCCodeView.h - Machine Code CodeView support -------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Holds state from .cv_file and .cv_loc directives for later emission.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCCodeView.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/DebugInfo/CodeView/CodeView.h"
+#include "llvm/DebugInfo/CodeView/Line.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCObjectStreamer.h"
+#include "llvm/Support/COFF.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+
+CodeViewContext::CodeViewContext() {}
+
+CodeViewContext::~CodeViewContext() {
+  // If someone inserted strings into the string table but never actually
+  // emitted them somewhere, clean up the fragment.
+  if (!InsertedStrTabFragment)
+    delete StrTabFragment;
+}
+
+/// This is a valid number for use with .cv_loc if we've already seen a .cv_file
+/// for it.
+bool CodeViewContext::isValidFileNumber(unsigned FileNumber) const {
+  unsigned Idx = FileNumber - 1;
+  if (Idx < Filenames.size())
+    return !Filenames[Idx].empty();
+  return false;
+}
+
+bool CodeViewContext::addFile(unsigned FileNumber, StringRef Filename) {
+  assert(FileNumber > 0);
+  Filename = addToStringTable(Filename);
+  unsigned Idx = FileNumber - 1;
+  if (Idx >= Filenames.size())
+    Filenames.resize(Idx + 1);
+
+  if (Filename.empty())
+    Filename = "<stdin>";
+
+  if (!Filenames[Idx].empty())
+    return false;
+
+  // FIXME: We should store the string table offset of the filename, rather than
+  // the filename itself for efficiency.
+  Filename = addToStringTable(Filename);
+
+  Filenames[Idx] = Filename;
+  return true;
+}
+
+MCDataFragment *CodeViewContext::getStringTableFragment() {
+  if (!StrTabFragment) {
+    StrTabFragment = new MCDataFragment();
+    // Start a new string table out with a null byte.
+    StrTabFragment->getContents().push_back('\0');
+  }
+  return StrTabFragment;
+}
+
+StringRef CodeViewContext::addToStringTable(StringRef S) {
+  SmallVectorImpl<char> &Contents = getStringTableFragment()->getContents();
+  auto Insertion =
+      StringTable.insert(std::make_pair(S, unsigned(Contents.size())));
+  // Return the string from the table, since it is stable.
+  S = Insertion.first->first();
+  if (Insertion.second) {
+    // The string map key is always null terminated.
+    Contents.append(S.begin(), S.end() + 1);
+  }
+  return S;
+}
+
+unsigned CodeViewContext::getStringTableOffset(StringRef S) {
+  // A string table offset of zero is always the empty string.
+  if (S.empty())
+    return 0;
+  auto I = StringTable.find(S);
+  assert(I != StringTable.end());
+  return I->second;
+}
+
+void CodeViewContext::emitStringTable(MCObjectStreamer &OS) {
+  MCContext &Ctx = OS.getContext();
+  MCSymbol *StringBegin = Ctx.createTempSymbol("strtab_begin"),
+           *StringEnd = Ctx.createTempSymbol("strtab_end");
+
+  OS.EmitIntValue(unsigned(ModuleSubstreamKind::StringTable), 4);
+  OS.emitAbsoluteSymbolDiff(StringEnd, StringBegin, 4);
+  OS.EmitLabel(StringBegin);
+
+  // Put the string table data fragment here, if we haven't already put it
+  // somewhere else. If somebody wants two string tables in their .s file, one
+  // will just be empty.
+  if (!InsertedStrTabFragment) {
+    OS.insert(getStringTableFragment());
+    InsertedStrTabFragment = true;
+  }
+
+  OS.EmitValueToAlignment(4, 0);
+
+  OS.EmitLabel(StringEnd);
+}
+
+void CodeViewContext::emitFileChecksums(MCObjectStreamer &OS) {
+  MCContext &Ctx = OS.getContext();
+  MCSymbol *FileBegin = Ctx.createTempSymbol("filechecksums_begin"),
+           *FileEnd = Ctx.createTempSymbol("filechecksums_end");
+
+  OS.EmitIntValue(unsigned(ModuleSubstreamKind::FileChecksums), 4);
+  OS.emitAbsoluteSymbolDiff(FileEnd, FileBegin, 4);
+  OS.EmitLabel(FileBegin);
+
+  // Emit an array of FileChecksum entries. We index into this table using the
+  // user-provided file number. Each entry is currently 8 bytes, as we don't
+  // emit checksums.
+  for (StringRef Filename : Filenames) {
+    OS.EmitIntValue(getStringTableOffset(Filename), 4);
+    // Zero the next two fields and align back to 4 bytes. This indicates that
+    // no checksum is present.
+    OS.EmitIntValue(0, 4);
+  }
+
+  OS.EmitLabel(FileEnd);
+}
+
+void CodeViewContext::emitLineTableForFunction(MCObjectStreamer &OS,
+                                               unsigned FuncId,
+                                               const MCSymbol *FuncBegin,
+                                               const MCSymbol *FuncEnd) {
+  MCContext &Ctx = OS.getContext();
+  MCSymbol *LineBegin = Ctx.createTempSymbol("linetable_begin"),
+           *LineEnd = Ctx.createTempSymbol("linetable_end");
+
+  OS.EmitIntValue(unsigned(ModuleSubstreamKind::Lines), 4);
+  OS.emitAbsoluteSymbolDiff(LineEnd, LineBegin, 4);
+  OS.EmitLabel(LineBegin);
+  OS.EmitCOFFSecRel32(FuncBegin);
+  OS.EmitCOFFSectionIndex(FuncBegin);
+
+  // Actual line info.
+  ArrayRef<MCCVLineEntry> Locs = getFunctionLineEntries(FuncId);
+  bool HaveColumns = any_of(Locs, [](const MCCVLineEntry &LineEntry) {
+    return LineEntry.getColumn() != 0;
+  });
+  OS.EmitIntValue(HaveColumns ? int(codeview::LineFlags::HaveColumns) : 0, 2);
+  OS.emitAbsoluteSymbolDiff(FuncEnd, FuncBegin, 4);
+
+  for (auto I = Locs.begin(), E = Locs.end(); I != E;) {
+    // Emit a file segment for the run of locations that share a file id.
+    unsigned CurFileNum = I->getFileNum();
+    auto FileSegEnd =
+        std::find_if(I, E, [CurFileNum](const MCCVLineEntry &Loc) {
+          return Loc.getFileNum() != CurFileNum;
+        });
+    unsigned EntryCount = FileSegEnd - I;
+    OS.AddComment("Segment for file '" + Twine(Filenames[CurFileNum - 1]) +
+                  "' begins");
+    OS.EmitIntValue(8 * (CurFileNum - 1), 4);
+    OS.EmitIntValue(EntryCount, 4);
+    uint32_t SegmentSize = 12;
+    SegmentSize += 8 * EntryCount;
+    if (HaveColumns)
+      SegmentSize += 4 * EntryCount;
+    OS.EmitIntValue(SegmentSize, 4);
+
+    for (auto J = I; J != FileSegEnd; ++J) {
+      OS.emitAbsoluteSymbolDiff(J->getLabel(), FuncBegin, 4);
+      unsigned LineData = J->getLine();
+      if (J->isStmt())
+        LineData |= codeview::LineInfo::StatementFlag;
+      OS.EmitIntValue(LineData, 4);
+    }
+    if (HaveColumns) {
+      for (auto J = I; J != FileSegEnd; ++J) {
+        OS.EmitIntValue(J->getColumn(), 2);
+        OS.EmitIntValue(0, 2);
+      }
+    }
+    I = FileSegEnd;
+  }
+  OS.EmitLabel(LineEnd);
+}
+
+//
+// This is called when an instruction is assembled into the specified section
+// and if there is information from the last .cv_loc directive that has yet to have
+// a line entry made for it is made.
+//
+void MCCVLineEntry::Make(MCObjectStreamer *MCOS) {
+  if (!MCOS->getContext().getCVLocSeen())
+    return;
+
+  // Create a symbol at in the current section for use in the line entry.
+  MCSymbol *LineSym = MCOS->getContext().createTempSymbol();
+  // Set the value of the symbol to use for the MCCVLineEntry.
+  MCOS->EmitLabel(LineSym);
+
+  // Get the current .loc info saved in the context.
+  const MCCVLoc &CVLoc = MCOS->getContext().getCurrentCVLoc();
+
+  // Create a (local) line entry with the symbol and the current .loc info.
+  MCCVLineEntry LineEntry(LineSym, CVLoc);
+
+  // clear CVLocSeen saying the current .loc info is now used.
+  MCOS->getContext().clearCVLocSeen();
+
+  // Add the line entry to this section's entries.
+  MCOS->getContext().getCVContext().addLineEntry(LineEntry);
+}