DebugInfo: Migrate callers from getAsCString to dwarf::toString

This makes a bunch of these call sites independent of a follow-up change
I'm making to have getAsCString return Expected<const char*> for more
descriptive error messages so that the failures there can be
communicated up to DWARFVerifier (or other callers who want to provide
more verbose diagnostics) so DWARFVerifier doesn't have to re-implement
the string lookup logic and error checking.

Author: dwblaikie

llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h

@@ -199,7 +199,9 @@ inline StringRef toStringRef(const Optional<DWARFFormValue> &V,
 /// form value's encoding wasn't a string.
 inline const char *toString(const Optional<DWARFFormValue> &V,
                             const char *Default) {
-  return toString(V).getValueOr(Default);
+  if (auto E = toString(V))
+    return *E;
+  return Default;
 }
 
 /// Take an optional DWARFFormValue and try to extract an unsigned constant.

llvm/lib/DWARFLinker/DWARFLinker.cpp

@@ -223,22 +223,21 @@ static void analyzeImportedModule(
     SysRoot = CU.getSysRoot();
   if (!SysRoot.empty() && Path.startswith(SysRoot))
     return;
-  if (Optional<DWARFFormValue> Val = DIE.find(dwarf::DW_AT_name))
-    if (Optional<const char *> Name = Val->getAsCString()) {
-      auto &Entry = (*ParseableSwiftInterfaces)[*Name];
-      // The prepend path is applied later when copying.
-      DWARFDie CUDie = CU.getOrigUnit().getUnitDIE();
-      SmallString<128> ResolvedPath;
-      if (sys::path::is_relative(Path))
-        resolveRelativeObjectPath(ResolvedPath, CUDie);
-      sys::path::append(ResolvedPath, Path);
-      if (!Entry.empty() && Entry != ResolvedPath)
-        ReportWarning(
-            Twine("Conflicting parseable interfaces for Swift Module ") +
-                *Name + ": " + Entry + " and " + Path,
-            DIE);
-      Entry = std::string(ResolvedPath.str());
-    }
+  Optional<const char*> Name = dwarf::toString(DIE.find(dwarf::DW_AT_name));
+  if (!Name)
+    return;
+  auto &Entry = (*ParseableSwiftInterfaces)[*Name];
+  // The prepend path is applied later when copying.
+  DWARFDie CUDie = CU.getOrigUnit().getUnitDIE();
+  SmallString<128> ResolvedPath;
+  if (sys::path::is_relative(Path))
+    resolveRelativeObjectPath(ResolvedPath, CUDie);
+  sys::path::append(ResolvedPath, Path);
+  if (!Entry.empty() && Entry != ResolvedPath)
+    ReportWarning(Twine("Conflicting parseable interfaces for Swift Module ") +
+                      *Name + ": " + Entry + " and " + Path,
+                  DIE);
+  Entry = std::string(ResolvedPath.str());
 }
 
 /// The distinct types of work performed by the work loop in
@@ -846,7 +845,7 @@ void DWARFLinker::assignAbbrev(DIEAbbrev &Abbrev) {
 unsigned DWARFLinker::DIECloner::cloneStringAttribute(
     DIE &Die, AttributeSpec AttrSpec, const DWARFFormValue &Val,
     const DWARFUnit &U, OffsetsStringPool &StringPool, AttributesInfo &Info) {
-  Optional<const char *> String = Val.getAsCString();
+  Optional<const char *> String = dwarf::toString(Val);
   if (!String)
     return 0;
 

llvm/lib/DebugInfo/DWARF/DWARFContext.cpp

@@ -1195,7 +1195,7 @@ void DWARFContext::addLocalsForDie(DWARFCompileUnit *CU, DWARFDie Subprogram,
             Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
       Die = Origin;
     if (auto NameAttr = Die.find(DW_AT_name))
-      if (Optional<const char *> Name = NameAttr->getAsCString())
+      if (Optional<const char *> Name = dwarf::toString(*NameAttr))
         Local.Name = *Name;
     if (auto Type = Die.getAttributeValueAsReferencedDie(DW_AT_type))
       Local.Size = getTypeSize(Type, getCUAddrSize());

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

@@ -1331,8 +1331,8 @@ Optional<StringRef> DWARFDebugLine::LineTable::getSourceByIndex(uint64_t FileInd
   if (Kind == FileLineInfoKind::None || !Prologue.hasFileAtIndex(FileIndex))
     return None;
   const FileNameEntry &Entry = Prologue.getFileNameEntry(FileIndex);
-  if (Optional<const char *> source = Entry.Source.getAsCString())
-    return StringRef(*source);
+  if (auto E = dwarf::toString(Entry.Source))
+    return StringRef(*E);
   return None;
 }
 
@@ -1350,10 +1350,10 @@ bool DWARFDebugLine::Prologue::getFileNameByIndex(
   if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
     return false;
   const FileNameEntry &Entry = getFileNameEntry(FileIndex);
-  Optional<const char *> Name = Entry.Name.getAsCString();
-  if (!Name)
+  auto E = dwarf::toString(Entry.Name);
+  if (!E)
     return false;
-  StringRef FileName = *Name;
+  StringRef FileName = *E;
   if (Kind == FileLineInfoKind::RawValue ||
       isPathAbsoluteOnWindowsOrPosix(FileName)) {
     Result = std::string(FileName);
@@ -1372,11 +1372,10 @@ bool DWARFDebugLine::Prologue::getFileNameByIndex(
     // relative names.
     if ((Entry.DirIdx != 0 || Kind != FileLineInfoKind::RelativeFilePath) &&
         Entry.DirIdx < IncludeDirectories.size())
-      IncludeDir = IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
+      IncludeDir = dwarf::toStringRef(IncludeDirectories[Entry.DirIdx]);
   } else {
     if (0 < Entry.DirIdx && Entry.DirIdx <= IncludeDirectories.size())
-      IncludeDir =
-          IncludeDirectories[Entry.DirIdx - 1].getAsCString().getValue();
+      IncludeDir = dwarf::toStringRef(IncludeDirectories[Entry.DirIdx - 1]);
   }
 
   // For absolute paths only, include the compilation directory of compile unit.

llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp

@@ -217,8 +217,8 @@ static void prettyPrintBaseTypeRef(DWARFUnit *U, raw_ostream &OS,
     if (DumpOpts.Verbose)
       OS << format("0x%08" PRIx64 " -> ", Operands[Operand]);
     OS << format("0x%08" PRIx64 ")", U->getOffset() + Operands[Operand]);
-    if (auto Name = Die.find(dwarf::DW_AT_name))
-      OS << " \"" << Name->getAsCString() << "\"";
+    if (auto Name = dwarf::toString(Die.find(dwarf::DW_AT_name)))
+      OS << " \"" << *Name << "\"";
   } else {
     OS << format(" <invalid base_type ref: 0x%" PRIx64 ">",
                  Operands[Operand]);

llvm/tools/obj2yaml/dwarf2yaml.cpp

@@ -291,8 +291,8 @@ void dumpDebugInfo(DWARFContext &DCtx, DWARFYAML::Data &Y) {
                 NewValue.Value = Val.getValue();
               break;
             case dwarf::DW_FORM_string:
-              if (auto Val = FormValue.getValue().getAsCString())
-                NewValue.CStr = Val.getValue();
+              if (auto Val = dwarf::toString(FormValue))
+                NewValue.CStr = *Val;
               break;
             case dwarf::DW_FORM_indirect:
               indirect = true;

llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp

@@ -1504,7 +1504,7 @@ TEST(DWARFDebugInfo, TestAttributeIterators) {
 
   ASSERT_NE(E, I);
   EXPECT_EQ(I->Attr, DW_AT_name);
-  auto ActualCUPath = I->Value.getAsCString();
+  auto ActualCUPath = toString(I->Value);
   EXPECT_EQ(CUPath, *ActualCUPath);
 
   ASSERT_NE(E, ++I);

llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp

@@ -170,11 +170,11 @@ void checkDefaultPrologue(uint16_t Version, DwarfFormat Format,
   EXPECT_EQ(Prologue.StandardOpcodeLengths, ExpectedLengths);
   ASSERT_EQ(Prologue.IncludeDirectories.size(), 1u);
   ASSERT_EQ(Prologue.IncludeDirectories[0].getForm(), DW_FORM_string);
-  EXPECT_STREQ(*Prologue.IncludeDirectories[0].getAsCString(), "a dir");
+  EXPECT_STREQ(*toString(Prologue.IncludeDirectories[0]), "a dir");
   ASSERT_EQ(Prologue.FileNames.size(), 1u);
   ASSERT_EQ(Prologue.FileNames[0].Name.getForm(), DW_FORM_string);
   ASSERT_EQ(Prologue.FileNames[0].DirIdx, 0u);
-  EXPECT_STREQ(*Prologue.FileNames[0].Name.getAsCString(), "a file");
+  EXPECT_STREQ(*toString(Prologue.FileNames[0].Name), "a file");
 }
 
 #ifdef _AIX

llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp

@@ -336,15 +336,13 @@ static void writeCString(StringRef Str, AsmPrinter &Asm) {
 
 static void writeV2IncludeAndFileTable(const DWARFDebugLine::Prologue &Prologue,
                                        AsmPrinter &Asm) {
-  for (auto Include : Prologue.IncludeDirectories) {
-    assert(Include.getAsCString() && "expected a string form for include dir");
-    writeCString(*Include.getAsCString(), Asm);
-  }
+  for (auto Include : Prologue.IncludeDirectories)
+    writeCString(*toString(Include), Asm);
+
   Asm.emitInt8(0);
 
   for (auto File : Prologue.FileNames) {
-    assert(File.Name.getAsCString() && "expected a string form for file name");
-    writeCString(*File.Name.getAsCString(), Asm);
+    writeCString(*toString(File.Name), Asm);
     Asm.emitULEB128(File.DirIdx);
     Asm.emitULEB128(File.ModTime);
     Asm.emitULEB128(File.Length);
@@ -360,10 +358,8 @@ static void writeV5IncludeAndFileTable(const DWARFDebugLine::Prologue &Prologue,
   Asm.emitULEB128(DW_LNCT_path);
   Asm.emitULEB128(DW_FORM_string);
   Asm.emitULEB128(Prologue.IncludeDirectories.size());
-  for (auto Include : Prologue.IncludeDirectories) {
-    assert(Include.getAsCString() && "expected a string form for include dir");
-    writeCString(*Include.getAsCString(), Asm);
-  }
+  for (auto Include : Prologue.IncludeDirectories)
+    writeCString(*toString(Include), Asm);
 
   Asm.emitInt8(2); // file_name_entry_format_count.
   Asm.emitULEB128(DW_LNCT_path);
@@ -372,8 +368,7 @@ static void writeV5IncludeAndFileTable(const DWARFDebugLine::Prologue &Prologue,
   Asm.emitULEB128(DW_FORM_data1);
   Asm.emitULEB128(Prologue.FileNames.size());
   for (auto File : Prologue.FileNames) {
-    assert(File.Name.getAsCString() && "expected a string form for file name");
-    writeCString(*File.Name.getAsCString(), Asm);
+    writeCString(*toString(File.Name), Asm);
     Asm.emitInt8(File.DirIdx);
   }
 }