[DebugInfo] Move function from line table to the prologue (NFC)

In LLDB, when parsing type units, we don't need to parse the whole line
table. Instead, we only need to parse the "support files" from the line
table prologue.

To make that possible, this patch moves the respective functions from
the LineTable into the Prologue. Because I don't think users of the
LineTable should have to know that these files come from the Prologue,

I've left the original methods in place, and made them redirect to the
LineTable.

Differential revision: https://reviews.llvm.org/D64774

llvm-svn: 366158

1 files changed, 33 insertions, 34 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
index 9f9aaabf1e8..8a621084710 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -66,6 +66,26 @@ void DWARFDebugLine::ContentTypeTracker::trackContentType(
 
 DWARFDebugLine::Prologue::Prologue() { clear(); }
 
+bool DWARFDebugLine::Prologue::hasFileAtIndex(uint64_t FileIndex) const {
+  uint16_t DwarfVersion = getVersion();
+  assert(DwarfVersion != 0 &&
+         "line table prologue has no dwarf version information");
+  if (DwarfVersion >= 5)
+    return FileIndex < FileNames.size();
+  return FileIndex != 0 && FileIndex <= FileNames.size();
+}
+
+const llvm::DWARFDebugLine::FileNameEntry &
+DWARFDebugLine::Prologue::getFileNameEntry(uint64_t Index) const {
+  uint16_t DwarfVersion = getVersion();
+  assert(DwarfVersion != 0 &&
+         "line table prologue has no dwarf version information");
+  // In DWARF v5 the file names are 0-indexed.
+  if (DwarfVersion >= 5)
+    return FileNames[Index];
+  return FileNames[Index - 1];
+}
+
 void DWARFDebugLine::Prologue::clear() {
   TotalLength = PrologueLength = 0;
   SegSelectorSize = 0;
@@ -968,30 +988,11 @@ bool DWARFDebugLine::LineTable::lookupAddressRangeImpl(
   return true;
 }
 
-bool DWARFDebugLine::LineTable::hasFileAtIndex(uint64_t FileIndex) const {
-  uint16_t DwarfVersion = Prologue.getVersion();
-  assert(DwarfVersion != 0 && "LineTable has no dwarf version information");
-  if (DwarfVersion >= 5)
-    return FileIndex < Prologue.FileNames.size();
-  return FileIndex != 0 && FileIndex <= Prologue.FileNames.size();
-}
-
-const llvm::DWARFDebugLine::FileNameEntry &
-DWARFDebugLine::LineTable::getFileNameEntry(uint64_t Index) const {
-  uint16_t DwarfVersion = Prologue.getVersion();
-  assert(DwarfVersion != 0 && "LineTable has no dwarf version information");
-  // In DWARF v5 the file names are 0-indexed.
-  if (DwarfVersion >= 5)
-    return Prologue.FileNames[Index];
-  else
-    return Prologue.FileNames[Index - 1];
-}
-
 Optional<StringRef> DWARFDebugLine::LineTable::getSourceByIndex(uint64_t FileIndex,
                                                                 FileLineInfoKind Kind) const {
-  if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
+  if (Kind == FileLineInfoKind::None || !Prologue.hasFileAtIndex(FileIndex))
     return None;
-  const FileNameEntry &Entry = getFileNameEntry(FileIndex);
+  const FileNameEntry &Entry = Prologue.getFileNameEntry(FileIndex);
   if (Optional<const char *> source = Entry.Source.getAsCString())
     return StringRef(*source);
   return None;
@@ -1005,10 +1006,10 @@ static bool isPathAbsoluteOnWindowsOrPosix(const Twine &Path) {
          sys::path::is_absolute(Path, sys::path::Style::windows);
 }
 
-bool DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
-                                                   const char *CompDir,
-                                                   FileLineInfoKind Kind,
-                                                   std::string &Result) const {
+bool DWARFDebugLine::Prologue::getFileNameByIndex(uint64_t FileIndex,
+                                                  StringRef CompDir,
+                                                  FileLineInfoKind Kind,
+                                                  std::string &Result) const {
   if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
     return false;
   const FileNameEntry &Entry = getFileNameEntry(FileIndex);
@@ -1022,20 +1023,18 @@ bool DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
   SmallString<16> FilePath;
   StringRef IncludeDir;
   // Be defensive about the contents of Entry.
-  if (Prologue.getVersion() >= 5) {
-    if (Entry.DirIdx < Prologue.IncludeDirectories.size())
-      IncludeDir =
-          Prologue.IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
+  if (getVersion() >= 5) {
+    if (Entry.DirIdx < IncludeDirectories.size())
+      IncludeDir = IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
   } else {
-    if (0 < Entry.DirIdx && Entry.DirIdx <= Prologue.IncludeDirectories.size())
-      IncludeDir = Prologue.IncludeDirectories[Entry.DirIdx - 1]
-                       .getAsCString()
-                       .getValue();
+    if (0 < Entry.DirIdx && Entry.DirIdx <= IncludeDirectories.size())
+      IncludeDir =
+          IncludeDirectories[Entry.DirIdx - 1].getAsCString().getValue();
 
     // We may still need to append compilation directory of compile unit.
     // We know that FileName is not absolute, the only way to have an
     // absolute path at this point would be if IncludeDir is absolute.
-    if (CompDir && !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
+    if (!CompDir.empty() && !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
       sys::path::append(FilePath, CompDir);
   }