[DWARF] Refactor DWARF classes to use unified error reporting. NFC.

[vleschuk]

Summary

DWARF-related classes in lib/DebugInfo/DWARF contained duplicating code for creating StringError instances, like:

template <typename... Ts>                                                      
static Error createError(char const *Fmt, const Ts &... Vals) {                
  std::string Buffer;                                                          
  raw_string_ostream Stream(Buffer);                                           
  Stream << format(Fmt, Vals...);                                              
  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
}

Similar function was placed in Support lib in https://reviews.llvm.org/D49824 .

This revision makes DWARF classes use this function instead of their local implementation of it.

[vleschuk]

lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp

27

@wolfgangp I have compiled new code with gcc (7.2.1) and it compiles correctly and passes all tests. Could you please let me know if we can safely get rid of this workaround here?

[JDevlieghere]

include/llvm/DebugInfo/DWARF/DWARFListTable.h

213–214

Although having an inconvertibleErrorCode (as per Lang's comment in the other diff) prevents conversion between errors and error codes, I'm not convinced it's actually needed here. If we don't need the conversion in libDebugInfo (which I think we don't) I'd rather have an inconvertible one instead of whichever is close enough.

lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp

27

We officially support GCC 4.8.0 and later, so whether it compiles with 7.2.1 doesn't really tell us much. I believe we have bots running pretty old versions of GCC so you could try removing and see if any of them are failing (or you get complaints from downstream users).

[vleschuk]

include/llvm/DebugInfo/DWARF/DWARFListTable.h

213–214

During https://reviews.llvm.org/D49676 it was decided to use convertible error codes in such situations. I think we should have consistent behavior along code sections (in this case style should be similar in all DebugInfo/DWARF* classes).

lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp

27

I have tested it, build fails if we just remove this part from code, however everything works fine if we fully apply the patch from this revision and replace calls to createError() with the createStringError(). Tested with clang 6.0, gcc 4.8, 4.9 and 7.2.

[wolfgangp]

lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp

27

I have compiled new code with gcc (7.2.1) and it compiles correctly and passes all tests.
Could you please let me know if we can safely get rid of this workaround here?

It certainly looks like after your changes the workaround is no longer needed since we don't need the explicit specialization of 'createError' any more.

[vleschuk]

lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp

27

Thanks a lot for confirmation!

[vleschuk]

Does anyone have more questions/suggestions/objections on this revision?

[JDevlieghere]

include/llvm/DebugInfo/DWARF/DWARFListTable.h

213–214

I'm probably overlooking it, but where exactly in D49676 was this decided? I don't mind per se, but I'd like to understand why we're doing this for future code reviews.

[vleschuk]

include/llvm/DebugInfo/DWARF/DWARFListTable.h

213–214

Sorry, I meant https://reviews.llvm.org/D49824

[vleschuk]

Ping. Any questions?

[JDevlieghere]

In the differential you linked we agreed to have the API include an error code as an argument. That still leaves us the option to pass an inconvertibleErrorCode() as the first argument.

Anyway, since nobody else seems to mind the switch to actual error codes, this LGTM. Thanks for taking the time to work on this, Victor!

[jhenderson]

lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp

399–402

Nit: The indentation looks a bit weird here. Is this how clang-format formats this?

518

No. Don't use this errc value here. file_exists is for files, as the name implies. This should be invalid_argument again, I guess (there isn't a code for "malformed input file").

618–619

You missed an inconvertibleErrorCode here...

Actually, looking at the function itself, it can NEVER fail (always returns true), so this is technically dead code. I'd consider changing the signature of the function to return void. But that should be a separate change. If you are going to do this, I'm okay with it continuing to be inconvertibleErrorCode, but otherwise, maybe io_error?

lib/DebugInfo/DWARF/DWARFContext.cpp

1601–1602

This should be invalid_argument, looking at the lookupTarget function (which actually should just return an Error itself rather than setting a string...)

lib/DebugInfo/DWARF/DWARFDebugFrame.cpp

51–53

I didn't know about this errc value. Good spot! Maybe it's worth using in one or two other cases where the input is malformed? What do you think?

lib/DebugInfo/DWARF/DWARFDebugLine.cpp

629–630

This might want to be illegal byte sequence.

837–838

This should be illegal_byte_sequence, I reckon.

lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp

93–94

Maybe not_supported here?

[probinson]

lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp

618–619

Re. extractValue() there's a place in DWARFDie.cpp that asserts the return value is true; but that's because DIEs come from a section that has actually been parsed already. Other places that use forms to interpret data are less (ahem) assertive, and this code isn't relying on a pre-parsed section, so I think returning an error would be appropriate.

[jhenderson]

I just noticed that llvmObject has an object_error equivalent to std::errc, with a make_error_code method allowing us to turn them into std::error_code for use with the new function. In particular, there are unexpected_eof and parser_failed errors, which might be more appropriate for certain situations in this file. What do you think?

[jhenderson]

Hi @vleschuk, I just wanted to quickly check-in on this to see if you need any help with making further improvements as suggested?

[vleschuk]

In D49964#1200459, @jhenderson wrote:

Hi @vleschuk, I just wanted to quickly check-in on this to see if you need any help with making further improvements as suggested?

Hello, sorry, had a delay with them, will update the review today/tomorrow.

[vleschuk]

lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp

618–619

Ok, using io_error for now.

lib/DebugInfo/DWARF/DWARFContext.cpp

1601–1602

looking at the lookupTarget function (which actually should just return an Error itself rather than setting a string...)

However return result of lookupTarget is used below. Changing its behavior is not related to this change... Setting invalid_argument.

lib/DebugInfo/DWARF/DWARFDebugFrame.cpp

51–53

Yep, used it for "Incorrectly terminated.." and "Section too small". Thanks for the tip.

[vleschuk]

In D49964#1186975, @jhenderson wrote:

I just noticed that llvmObject has an object_error equivalent to std::errc, with a make_error_code method allowing us to turn them into std::error_code for use with the new function. In particular, there are unexpected_eof and parser_failed errors, which might be more appropriate for certain situations in this file. What do you think?

unexpected_eof is not very appropriate, when sections are too small I used illegal_byte_sequence. Maybe we could use parser_failed to replace some invalid_argument's. But won't that enum number concur with some other? I suggest we leave it for separate change.

[vleschuk]

• Changed error codes to more appropriate ones
• Fixed formatting

[vleschuk]

@jhenderson Please take a look when you have time.

[jhenderson]

LGTM, from my point of view now.

include/llvm/DebugInfo/DWARF/DWARFListTable.h

226

This is probably another good place illegal_byte_sequence error.

lib/DebugInfo/DWARF/DWARFContext.cpp

1601–1602

Sorry, yeah, I meant an Expected. But no need to change that in this change.

include/llvm/DebugInfo/DWARF/DWARFListTable.h

 //===- DWARFListTable.h -----------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_DEBUGINFO_DWARFLISTTABLE_H
 #define LLVM_DEBUGINFO_DWARFLISTTABLE_H
 
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DIContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdint>
 #include <map>
 #include <vector>
 
 namespace llvm {

 template <typename ListEntryType> class DWARFListType {
   using EntryType = ListEntryType;
   using ListEntries = std::vector<EntryType>;
 
 protected:
   ListEntries Entries;
 
 public:
-  // FIXME: We need to consolidate the various verions of "createError"
-  // that are used in the DWARF consumer. Until then, this is a workaround.
-  Error createError(const char *, const char *, uint32_t);
-
   const ListEntries &getEntries() const { return Entries; }
   bool empty() const { return Entries.empty(); }
   void clear() { Entries.clear(); }
   Error extract(DWARFDataExtractor Data, uint32_t HeaderOffset, uint32_t End,
                 uint32_t *OffsetPtr, StringRef SectionName,
                 StringRef ListStringName);
 };
 

 
 template <typename ListEntryType>
 Error DWARFListType<ListEntryType>::extract(DWARFDataExtractor Data,
                                             uint32_t HeaderOffset, uint32_t End,
                                             uint32_t *OffsetPtr,
                                             StringRef SectionName,
                                             StringRef ListTypeString) {
   if (*OffsetPtr < HeaderOffset || *OffsetPtr >= End)
-    return createError("invalid %s list offset 0x%" PRIx32,
+    return createStringError(errc::invalid_argument,
+                       "invalid %s list offset 0x%" PRIx32,
                        ListTypeString.data(), *OffsetPtr);
   Entries.clear();
   while (*OffsetPtr < End) {
     ListEntryType Entry;
     if (Error E = Entry.extract(Data, End, OffsetPtr))
       return E;
     Entries.push_back(Entry);
     if (Entry.isSentinel())
       return Error::success();
   }
-  return createError("no end of list marker detected at end of %s table "
+  return createStringError(errc::invalid_argument,
+                     "no end of list marker detected at end of %s table "
                      "starting at offset 0x%" PRIx32,
                      SectionName.data(), HeaderOffset);
 }
 
 template <typename DWARFListType>
 void DWARFListTableBase<DWARFListType>::dump(raw_ostream &OS,
                                              DIDumpOptions DumpOpts) const {
   Header.dump(OS, DumpOpts);

lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp

 //===- DWARFAcceleratorTable.cpp ------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DJB.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstddef>
 #include <cstdint>
 #include <utility>
 

 static Atom formatAtom(unsigned Atom) { return {Atom}; }
 
 DWARFAcceleratorTable::~DWARFAcceleratorTable() = default;
 
 llvm::Error AppleAcceleratorTable::extract() {
   uint32_t Offset = 0;
 
   // Check that we can at least read the header.
-  if (!AccelSection.isValidOffset(offsetof(Header, HeaderDataLength)+4))
-    return make_error<StringError>("Section too small: cannot read header.",
-                                   inconvertibleErrorCode());
+  if (!AccelSection.isValidOffset(offsetof(Header, HeaderDataLength) + 4))
+    return createStringError(errc::illegal_byte_sequence,
+                             "Section too small: cannot read header.");
 
   Hdr.Magic = AccelSection.getU32(&Offset);
   Hdr.Version = AccelSection.getU16(&Offset);
   Hdr.HashFunction = AccelSection.getU16(&Offset);
   Hdr.BucketCount = AccelSection.getU32(&Offset);
   Hdr.HashCount = AccelSection.getU32(&Offset);
   Hdr.HeaderDataLength = AccelSection.getU32(&Offset);
 
   // Check that we can read all the hashes and offsets from the
   // section (see SourceLevelDebugging.rst for the structure of the index).
   // We need to substract one because we're checking for an *offset* which is
   // equal to the size for an empty table and hence pointer after the section.
   if (!AccelSection.isValidOffset(sizeof(Hdr) + Hdr.HeaderDataLength +
                                   Hdr.BucketCount * 4 + Hdr.HashCount * 8 - 1))
-    return make_error<StringError>(
-        "Section too small: cannot read buckets and hashes.",
-        inconvertibleErrorCode());
+    return createStringError(
+        errc::illegal_byte_sequence,
+        "Section too small: cannot read buckets and hashes.");
 
   HdrData.DIEOffsetBase = AccelSection.getU32(&Offset);
   uint32_t NumAtoms = AccelSection.getU32(&Offset);
 
   for (unsigned i = 0; i < NumAtoms; ++i) {
     uint16_t AtomType = AccelSection.getU16(&Offset);
     auto AtomForm = static_cast<dwarf::Form>(AccelSection.getU16(&Offset));
     HdrData.Atoms.push_back(std::make_pair(AtomType, AtomForm));
void DWARFDebugNames::Header::dump(ScopedPrinter &W) const {
   W.printHex("Abbreviations table size", AbbrevTableSize);
   W.startLine() << "Augmentation: '" << AugmentationString << "'\n";
 }
 
 llvm::Error DWARFDebugNames::Header::extract(const DWARFDataExtractor &AS,
                                              uint32_t *Offset) {
   // Check that we can read the fixed-size part.
   if (!AS.isValidOffset(*Offset + sizeof(HeaderPOD) - 1))
-    return make_error<StringError>("Section too small: cannot read header.",
-                                   inconvertibleErrorCode());
+    return createStringError(errc::illegal_byte_sequence,
+                             "Section too small: cannot read header.");
 
   UnitLength = AS.getU32(Offset);
   Version = AS.getU16(Offset);
   Padding = AS.getU16(Offset);
   CompUnitCount = AS.getU32(Offset);
   LocalTypeUnitCount = AS.getU32(Offset);
   ForeignTypeUnitCount = AS.getU32(Offset);
   BucketCount = AS.getU32(Offset);
   NameCount = AS.getU32(Offset);
   AbbrevTableSize = AS.getU32(Offset);
   AugmentationStringSize = alignTo(AS.getU32(Offset), 4);
 
   if (!AS.isValidOffsetForDataOfSize(*Offset, AugmentationStringSize))
-    return make_error<StringError>(
-        "Section too small: cannot read header augmentation.",
-        inconvertibleErrorCode());
+    return createStringError(
+        errc::illegal_byte_sequence,
+        "Section too small: cannot read header augmentation.");
   AugmentationString.resize(AugmentationStringSize);
   AS.getU8(Offset, reinterpret_cast<uint8_t *>(AugmentationString.data()),
            AugmentationStringSize);
   return Error::success();
 }
 
 void DWARFDebugNames::Abbrev::dump(ScopedPrinter &W) const {
   DictScope AbbrevScope(W, ("Abbreviation 0x" + Twine::utohexstr(Code)).str());
   W.startLine() << formatv("Tag: {0}\n", Tag);

 
 DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getTombstoneKey() {
   return DWARFDebugNames::Abbrev(~0, dwarf::Tag(0), {});
 }
 
 Expected<DWARFDebugNames::AttributeEncoding>
 DWARFDebugNames::NameIndex::extractAttributeEncoding(uint32_t *Offset) {
   if (*Offset >= EntriesBase) {
-    return make_error<StringError>("Incorrectly terminated abbreviation table.",
-                                   inconvertibleErrorCode());
+    return createStringError(errc::illegal_byte_sequence,
+                             "Incorrectly terminated abbreviation table.");
   }
 
   uint32_t Index = Section.AccelSection.getULEB128(Offset);
   uint32_t Form = Section.AccelSection.getULEB128(Offset);
   return AttributeEncoding(dwarf::Index(Index), dwarf::Form(Form));
 }
 
 Expected<std::vector<DWARFDebugNames::AttributeEncoding>>
 DWARFDebugNames::NameIndex::extractAttributeEncodings(uint32_t *Offset) {
   std::vector<AttributeEncoding> Result;
   for (;;) {
     auto AttrEncOr = extractAttributeEncoding(Offset);
     if (!AttrEncOr)
       return AttrEncOr.takeError();
     if (isSentinel(*AttrEncOr))
       return std::move(Result);
 
     Result.emplace_back(*AttrEncOr);
   }
 }
 
 Expected<DWARFDebugNames::Abbrev>
 DWARFDebugNames::NameIndex::extractAbbrev(uint32_t *Offset) {
   if (*Offset >= EntriesBase) {
-    return make_error<StringError>("Incorrectly terminated abbreviation table.",
-                                   inconvertibleErrorCode());
+    return createStringError(errc::illegal_byte_sequence,
+                             "Incorrectly terminated abbreviation table.");
   }
 
   uint32_t Code = Section.AccelSection.getULEB128(Offset);
   if (Code == 0)
     return sentinelAbbrev();
 
   uint32_t Tag = Section.AccelSection.getULEB128(Offset);
   auto AttrEncOr = extractAttributeEncodings(Offset);
Error DWARFDebugNames::NameIndex::extract() {
   if (Hdr.BucketCount > 0)
     Offset += Hdr.NameCount * 4;
   StringOffsetsBase = Offset;
   Offset += Hdr.NameCount * 4;
   EntryOffsetsBase = Offset;
   Offset += Hdr.NameCount * 4;
 
   if (!AS.isValidOffsetForDataOfSize(Offset, Hdr.AbbrevTableSize))
-    return make_error<StringError>(
-        "Section too small: cannot read abbreviations.",
-        inconvertibleErrorCode());
+    return createStringError(errc::illegal_byte_sequence,
+                             "Section too small: cannot read abbreviations.");
 
   EntriesBase = Offset + Hdr.AbbrevTableSize;
 
   for (;;) {
     auto AbbrevOr = extractAbbrev(&Offset);
     if (!AbbrevOr)
       return AbbrevOr.takeError();
     if (isSentinel(*AbbrevOr))
       return Error::success();
 
-    if (!Abbrevs.insert(std::move(*AbbrevOr)).second) {
-      return make_error<StringError>("Duplicate abbreviation code.",
-                                     inconvertibleErrorCode());
-    }
+    if (!Abbrevs.insert(std::move(*AbbrevOr)).second)
+      return createStringError(errc::invalid_argument,
+                               "Duplicate abbreviation code.");
   }
 }
 DWARFDebugNames::Entry::Entry(const NameIndex &NameIdx, const Abbrev &Abbr)
     : NameIdx(&NameIdx), Abbr(&Abbr) {
   // This merely creates form values. It is up to the caller
   // (NameIndex::getEntry) to populate them.
   Values.reserve(Abbr.Attributes.size());
   for (const auto &Attr : Abbr.Attributes)
uint64_t DWARFDebugNames::NameIndex::getForeignTUSignature(uint32_t TU) const {
   uint32_t Offset = CUsBase + (Hdr.CompUnitCount + Hdr.LocalTypeUnitCount) * 4;
   return Section.AccelSection.getU64(&Offset);
 }
 
 Expected<DWARFDebugNames::Entry>
 DWARFDebugNames::NameIndex::getEntry(uint32_t *Offset) const {
   const DWARFDataExtractor &AS = Section.AccelSection;
   if (!AS.isValidOffset(*Offset))
-    return make_error<StringError>("Incorrectly terminated entry list.",
-                                   inconvertibleErrorCode());
+    return createStringError(errc::illegal_byte_sequence,
+                             "Incorrectly terminated entry list.");
 
   uint32_t AbbrevCode = AS.getULEB128(Offset);
   if (AbbrevCode == 0)
     return make_error<SentinelError>();
 
   const auto AbbrevIt = Abbrevs.find_as(AbbrevCode);
   if (AbbrevIt == Abbrevs.end())
-    return make_error<StringError>("Invalid abbreviation.",
-                                   inconvertibleErrorCode());
+    return createStringError(errc::invalid_argument, "Invalid abbreviation.");
 
   Entry E(*this, *AbbrevIt);
 
   dwarf::FormParams FormParams = {Hdr.Version, 0, dwarf::DwarfFormat::DWARF32};
   for (auto &Value : E.Values) {
     if (!Value.extractValue(AS, Offset, FormParams))
-      return make_error<StringError>("Error extracting index attribute values.",
-                                     inconvertibleErrorCode());
+      return createStringError(errc::io_error,
+                               "Error extracting index attribute values.");
   }
   return std::move(E);
 }
 
 DWARFDebugNames::NameTableEntry
 DWARFDebugNames::NameIndex::getNameTableEntry(uint32_t Index) const {
   assert(0 < Index && Index <= Hdr.NameCount);
   uint32_t StringOffsetOffset = StringOffsetsBase + 4 * (Index - 1);

lib/DebugInfo/DWARF/DWARFContext.cpp

Error DWARFContext::loadRegisterInfo(const object::ObjectFile &Obj) {
   Triple TT;
   TT.setArch(Triple::ArchType(Obj.getArch()));
   TT.setVendor(Triple::UnknownVendor);
   TT.setOS(Triple::UnknownOS);
   std::string TargetLookupError;
   const Target *TheTarget =
       TargetRegistry::lookupTarget(TT.str(), TargetLookupError);
   if (!TargetLookupError.empty())
-    return make_error<StringError>(TargetLookupError, inconvertibleErrorCode());
+    return createStringError(errc::invalid_argument,
+                             TargetLookupError.c_str());
   RegInfo.reset(TheTarget->createMCRegInfo(TT.str()));
   return Error::success();
 }
 
 uint8_t DWARFContext::getCUAddrSize() {
   // In theory, different compile units may have different address byte
   // sizes, but for simplicity we just use the address byte size of the
   // last compile unit. In practice the address size field is repeated across

lib/DebugInfo/DWARF/DWARFDebugFrame.cpp

 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
 #include <cinttypes>
 #include <cstdint>
 #include <string>
while (*Offset < EndOffset) {
     uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK;
 
     if (Primary) {
       // If it's a primary opcode, the first operand is encoded in the bottom
       // bits of the opcode itself.
       uint64_t Op1 = Opcode & DWARF_CFI_PRIMARY_OPERAND_MASK;
       switch (Primary) {
       default:
-        return make_error<StringError>(
-            "Invalid primary CFI opcode",
-            std::make_error_code(std::errc::illegal_byte_sequence));
+        return createStringError(errc::illegal_byte_sequence,
+                                 "Invalid primary CFI opcode 0x%" PRIx8,
+                                 Primary);
       case DW_CFA_advance_loc:
       case DW_CFA_restore:
         addInstruction(Primary, Op1);
         break;
       case DW_CFA_offset:
         addInstruction(Primary, Op1, Data.getULEB128(Offset));
         break;
       }
     } else {
       // Extended opcode - its value is Opcode itself.
       switch (Opcode) {
       default:
-        return make_error<StringError>(
-            "Invalid extended CFI opcode",
-            std::make_error_code(std::errc::illegal_byte_sequence));
+        return createStringError(errc::illegal_byte_sequence,
+                                 "Invalid extended CFI opcode 0x%" PRIx8,
+                                 Opcode);
       case DW_CFA_nop:
       case DW_CFA_remember_state:
       case DW_CFA_restore_state:
       case DW_CFA_GNU_window_save:
         // No operands
         addInstruction(Opcode);
         break;
       case DW_CFA_set_loc:

lib/DebugInfo/DWARF/DWARFDebugLine.cpp

 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
 #include <cinttypes>
 #include <cstdint>
for (auto Descriptor : FileDescriptors) {
         break;
       }
     }
     FileNames.push_back(FileEntry);
   }
   return true;
 }
 
-template <typename... Ts>
-static std::string formatErrorString(char const *Fmt, const Ts &... Vals) {
-  std::string Buffer;
-  raw_string_ostream Stream(Buffer);
-  Stream << format(Fmt, Vals...);
-  return Stream.str();
-}
-
-template <typename... Ts>
-static Error createError(char const *Fmt, const Ts &... Vals) {
-  return make_error<StringError>(formatErrorString(Fmt, Vals...),
-                                 inconvertibleErrorCode());
-}
-
-static Error createError(char const *Msg) {
-  return make_error<StringError>(Msg, inconvertibleErrorCode());
-}
-
 Error DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
                                       uint32_t *OffsetPtr,
                                       const DWARFContext &Ctx,
                                       const DWARFUnit *U) {
   const uint64_t PrologueOffset = *OffsetPtr;
 
   clear();
   TotalLength = DebugLineData.getU32(OffsetPtr);
   if (TotalLength == UINT32_MAX) {
     FormParams.Format = dwarf::DWARF64;
     TotalLength = DebugLineData.getU64(OffsetPtr);
   } else if (TotalLength >= 0xffffff00) {
-    return createError(
+    return createStringError(errc::invalid_argument,
         "parsing line table prologue at offset 0x%8.8" PRIx64
         " unsupported reserved unit length found of value 0x%8.8" PRIx64,
         PrologueOffset, TotalLength);
   }
   FormParams.Version = DebugLineData.getU16(OffsetPtr);
   if (getVersion() < 2)
-    return createError("parsing line table prologue at offset 0x%8.8" PRIx64
+    return createStringError(errc::not_supported,
+                       "parsing line table prologue at offset 0x%8.8" PRIx64
                        " found unsupported version 0x%2.2" PRIx16,
                        PrologueOffset, getVersion());
 
   if (getVersion() >= 5) {
     FormParams.AddrSize = DebugLineData.getU8(OffsetPtr);
     assert((DebugLineData.getAddressSize() == 0 ||
             DebugLineData.getAddressSize() == getAddressSize()) &&
            "Line table header and data extractor disagree");
for (uint32_t I = 1; I < OpcodeBase; ++I) {
     uint8_t OpLen = DebugLineData.getU8(OffsetPtr);
     StandardOpcodeLengths.push_back(OpLen);
   }
 
   if (getVersion() >= 5) {
     if (!parseV5DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
                               FormParams, Ctx, U, ContentTypes,
                               IncludeDirectories, FileNames)) {
-      return createError(
+      return createStringError(errc::invalid_argument,
           "parsing line table prologue at 0x%8.8" PRIx64
           " found an invalid directory or file table description at"
           " 0x%8.8" PRIx64,
           PrologueOffset, (uint64_t)*OffsetPtr);
     }
   } else
     parseV2DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
                          ContentTypes, IncludeDirectories, FileNames);
 
   if (*OffsetPtr != EndPrologueOffset)
-    return createError("parsing line table prologue at 0x%8.8" PRIx64
+    return createStringError(errc::invalid_argument,
+                       "parsing line table prologue at 0x%8.8" PRIx64
                        " should have ended at 0x%8.8" PRIx64
                        " but it ended at 0x%8.8" PRIx64,
                        PrologueOffset, EndPrologueOffset, (uint64_t)*OffsetPtr);
   return Error::success();
 }
 
 DWARFDebugLine::Row::Row(bool DefaultIsStmt) { reset(DefaultIsStmt); }
 
if (Pos != LineTableMap.end())
     return &Pos->second;
   return nullptr;
 }
 
 Expected<const DWARFDebugLine::LineTable *> DWARFDebugLine::getOrParseLineTable(
     DWARFDataExtractor &DebugLineData, uint32_t Offset, const DWARFContext &Ctx,
     const DWARFUnit *U, std::function<void(Error)> RecoverableErrorCallback) {
   if (!DebugLineData.isValidOffset(Offset))
-    return createError("offset 0x%8.8" PRIx32
+    return createStringError(errc::invalid_argument, "offset 0x%8.8" PRIx32
                        " is not a valid debug line section offset",
                        Offset);
 
   std::pair<LineTableIter, bool> Pos =
       LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
   LineTable *LT = &Pos.first->second;
   if (Pos.second) {
     if (Error Err =
if (Opcode == 0) {
         // that affect the address register add a delta to it. This instruction
         // stores a relocatable value into it instead.
         //
         // Make sure the extractor knows the address size.  If not, infer it
         // from the size of the operand.
         if (DebugLineData.getAddressSize() == 0)
           DebugLineData.setAddressSize(Len - 1);
         else if (DebugLineData.getAddressSize() != Len - 1) {
-          return createError("mismatching address size at offset 0x%8.8" PRIx32
+          return createStringError(errc::invalid_argument,
+                             "mismatching address size at offset 0x%8.8" PRIx32
                              " expected 0x%2.2" PRIx8 " found 0x%2.2" PRIx64,
                              ExtOffset, DebugLineData.getAddressSize(),
                              Len - 1);
         }
         State.Row.Address = DebugLineData.getRelocatedAddress(OffsetPtr);
         if (OS)
           *OS << format(" (0x%16.16" PRIx64 ")", State.Row.Address);
         break;
if (Opcode == 0) {
         // Len doesn't include the zero opcode byte or the length itself, but
         // it does include the sub_opcode, so we have to adjust for that.
         (*OffsetPtr) += Len - 1;
         break;
       }
       // Make sure the stated and parsed lengths are the same.
       // Otherwise we have an unparseable line-number program.
       if (*OffsetPtr - ExtOffset != Len)
-        return createError("unexpected line op length at offset 0x%8.8" PRIx32
+        return createStringError(errc::illegal_byte_sequence,
+                           "unexpected line op length at offset 0x%8.8" PRIx32
                            " expected 0x%2.2" PRIx64 " found 0x%2.2" PRIx32,
                            ExtOffset, Len, *OffsetPtr - ExtOffset);
     } else if (Opcode < Prologue.OpcodeBase) {
       if (OS)
         *OS << LNStandardString(Opcode);
       switch (Opcode) {
       // Standard Opcodes
       case DW_LNS_copy:
if (Opcode == 0) {
       State.Row.Discriminator = 0;
     }
     if(OS)
       *OS << "\n";
   }
 
   if (!State.Sequence.Empty)
     RecoverableErrorCallback(
-        createError("last sequence in debug line table is not terminated!"));
+        createStringError(errc::illegal_byte_sequence,
+                    "last sequence in debug line table is not terminated!"));
 
   // Sort all sequences so that address lookup will work faster.
   if (!Sequences.empty()) {
     llvm::sort(Sequences.begin(), Sequences.end(), Sequence::orderByLowPC);
     // Note: actually, instruction address ranges of sequences should not
     // overlap (in shared objects and executables). If they do, the address
     // lookup would still work, though, but result would be ambiguous.
     // We don't report warning in this case. For example,

lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp

 //===- DWARFDebugRangesList.cpp -------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cinttypes>
 #include <cstdint>
 
 using namespace llvm;
 
-// FIXME: There are several versions of this. Consolidate them.
-template <typename... Ts>
-static Error createError(char const *Fmt, const Ts &... Vals) {
-  std::string Buffer;
-  raw_string_ostream Stream(Buffer);
-  Stream << format(Fmt, Vals...);
-  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
-}
-
 void DWARFDebugRangeList::clear() {
   Offset = -1U;
   AddressSize = 0;
   Entries.clear();
 }
 
 Error DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
                                    uint32_t *offset_ptr) {
   clear();
   if (!data.isValidOffset(*offset_ptr))
-    return createError("invalid range list offset 0x%" PRIx32, *offset_ptr);
+    return createStringError(errc::invalid_argument,
+                       "invalid range list offset 0x%" PRIx32, *offset_ptr);
 
   AddressSize = data.getAddressSize();
   if (AddressSize != 4 && AddressSize != 8)
-    return createError("invalid address size: %d", AddressSize);
+    return createStringError(errc::invalid_argument,
+                       "invalid address size: %" PRIu8, AddressSize);
   Offset = *offset_ptr;
   while (true) {
     RangeListEntry Entry;
     Entry.SectionIndex = -1ULL;
 
     uint32_t prev_offset = *offset_ptr;
     Entry.StartAddress = data.getRelocatedAddress(offset_ptr);
     Entry.EndAddress =
         data.getRelocatedAddress(offset_ptr, &Entry.SectionIndex);
 
     // Check that both values were extracted correctly.
     if (*offset_ptr != prev_offset + 2 * AddressSize) {
       clear();
-      return createError("invalid range list entry at offset 0x%" PRIx32,
+      return createStringError(errc::invalid_argument,
+                         "invalid range list entry at offset 0x%" PRIx32,
                          prev_offset);
     }
     if (Entry.isEndOfListEntry())
       break;
     Entries.push_back(Entry);
   }
   return Error::success();
 }

lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp

 //===- DWARFDebugRnglists.cpp ---------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFDebugRnglists.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
-template <typename... Ts>
-static Error createError(char const *Fmt, const Ts &... Vals) {
-  std::string Buffer;
-  raw_string_ostream Stream(Buffer);
-  Stream << format(Fmt, Vals...);
-  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
-}
-
-namespace llvm {   // workaround for gcc bug
-template <>
-Error DWARFListType<RangeListEntry>::createError(const char *Fmt, const char *s,
-                                                 uint32_t Val) {
-  return ::createError(Fmt, s, Val);
-}
-}
-
 Error RangeListEntry::extract(DWARFDataExtractor Data, uint32_t End,
                               uint32_t *OffsetPtr) {
   Offset = *OffsetPtr;
   SectionIndex = -1ULL;
   // The caller should guarantee that we have at least 1 byte available, so
   // we just assert instead of revalidate.
   assert(*OffsetPtr < End &&
          "not enough space to extract a rangelist encoding");
   uint8_t Encoding = Data.getU8(OffsetPtr);
 
   switch (Encoding) {
   case dwarf::DW_RLE_end_of_list:
     Value0 = Value1 = 0;
     break;
   // TODO: Support other encodings.
   case dwarf::DW_RLE_base_addressx:
-    return createError("unsupported rnglists encoding DW_RLE_base_addressx "
+    return createStringError(errc::not_supported,
+                       "unsupported rnglists encoding DW_RLE_base_addressx "
                        "at offset 0x%" PRIx32,
                        *OffsetPtr - 1);
   case dwarf::DW_RLE_startx_endx:
-    return createError("unsupported rnglists encoding DW_RLE_startx_endx at "
+    return createStringError(errc::not_supported,
+                       "unsupported rnglists encoding DW_RLE_startx_endx at "
                        "offset 0x%" PRIx32,
                        *OffsetPtr - 1);
   case dwarf::DW_RLE_startx_length:
-    return createError("unsupported rnglists encoding DW_RLE_startx_length "
+    return createStringError(errc::not_supported,
+                       "unsupported rnglists encoding DW_RLE_startx_length "
                        "at offset 0x%" PRIx32,
                        *OffsetPtr - 1);
   case dwarf::DW_RLE_offset_pair: {
     uint32_t PreviousOffset = *OffsetPtr - 1;
     Value0 = Data.getULEB128(OffsetPtr);
     Value1 = Data.getULEB128(OffsetPtr);
     if (End < *OffsetPtr)
-      return createError("read past end of table when reading "
+      return createStringError(errc::invalid_argument,
+                         "read past end of table when reading "
                          "DW_RLE_offset_pair encoding at offset 0x%" PRIx32,
                          PreviousOffset);
     break;
   }
   case dwarf::DW_RLE_base_address: {
     if ((End - *OffsetPtr) < Data.getAddressSize())
-      return createError("insufficient space remaining in table for "
+      return createStringError(errc::invalid_argument,
+                         "insufficient space remaining in table for "
                          "DW_RLE_base_address encoding at offset 0x%" PRIx32,
                          *OffsetPtr - 1);
     Value0 = Data.getRelocatedAddress(OffsetPtr, &SectionIndex);
     break;
   }
   case dwarf::DW_RLE_start_end: {
     if ((End - *OffsetPtr) < unsigned(Data.getAddressSize() * 2))
-      return createError("insufficient space remaining in table for "
+      return createStringError(errc::invalid_argument,
+                         "insufficient space remaining in table for "
                          "DW_RLE_start_end encoding "
                          "at offset 0x%" PRIx32,
                          *OffsetPtr - 1);
     Value0 = Data.getRelocatedAddress(OffsetPtr, &SectionIndex);
     Value1 = Data.getRelocatedAddress(OffsetPtr);
     break;
   }
   case dwarf::DW_RLE_start_length: {
     uint32_t PreviousOffset = *OffsetPtr - 1;
     Value0 = Data.getRelocatedAddress(OffsetPtr, &SectionIndex);
     Value1 = Data.getULEB128(OffsetPtr);
     if (End < *OffsetPtr)
-      return createError("read past end of table when reading "
+      return createStringError(errc::invalid_argument,
+                         "read past end of table when reading "
                          "DW_RLE_start_length encoding at offset 0x%" PRIx32,
                          PreviousOffset);
     break;
   }
   default:
-    return createError("unknown rnglists encoding 0x%" PRIx32
+    return createStringError(errc::not_supported,
+                       "unknown rnglists encoding 0x%" PRIx32
                        " at offset 0x%" PRIx32,
                        uint32_t(Encoding), *OffsetPtr - 1);
   }
 
   EntryKind = Encoding;
   return Error::success();
 }
 

lib/DebugInfo/DWARF/DWARFListTable.cpp

 //===- DWARFListTable.cpp ---------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFListTable.h"
 #include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
-template <typename... Ts>
-static Error createError(char const *Fmt, const Ts &... Vals) {
-  std::string Buffer;
-  raw_string_ostream Stream(Buffer);
-  Stream << format(Fmt, Vals...);
-  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
-}
-
 Error DWARFListTableHeader::extract(DWARFDataExtractor Data,
                                     uint32_t *OffsetPtr) {
   HeaderOffset = *OffsetPtr;
   // Read and verify the length field.
   if (!Data.isValidOffsetForDataOfSize(*OffsetPtr, sizeof(uint32_t)))
-    return createError("section is not large enough to contain a "
+    return createStringError(errc::invalid_argument,
+                       "section is not large enough to contain a "
                        "%s table length at offset 0x%" PRIx32,
                        SectionName.data(), *OffsetPtr);
   // TODO: Add support for DWARF64.
   HeaderData.Length = Data.getU32(OffsetPtr);
   if (HeaderData.Length == 0xffffffffu)
-    return createError("DWARF64 is not supported in %s at offset 0x%" PRIx32,
+    return createStringError(errc::not_supported,
+                       "DWARF64 is not supported in %s at offset 0x%" PRIx32,
                        SectionName.data(), HeaderOffset);
   Format = dwarf::DwarfFormat::DWARF32;
   if (HeaderData.Length + sizeof(uint32_t) < sizeof(Header))
-    return createError("%s table at offset 0x%" PRIx32
+    return createStringError(errc::invalid_argument,
+                       "%s table at offset 0x%" PRIx32
                        " has too small length (0x%" PRIx32
                        ") to contain a complete header",
                        SectionName.data(), HeaderOffset, length());
   uint32_t End = HeaderOffset + length();
   if (!Data.isValidOffsetForDataOfSize(HeaderOffset, End - HeaderOffset))
-    return createError("section is not large enough to contain a %s table "
+    return createStringError(errc::invalid_argument,
+                       "section is not large enough to contain a %s table "
                        "of length 0x%" PRIx32 " at offset 0x%" PRIx32,
                        SectionName.data(), length(), HeaderOffset);
 
   HeaderData.Version = Data.getU16(OffsetPtr);
   HeaderData.AddrSize = Data.getU8(OffsetPtr);
   HeaderData.SegSize = Data.getU8(OffsetPtr);
   HeaderData.OffsetEntryCount = Data.getU32(OffsetPtr);
 
   // Perform basic validation of the remaining header fields.
   if (HeaderData.Version != 5)
-    return createError("unrecognised %s table version %" PRIu16
+    return createStringError(errc::invalid_argument,
+                       "unrecognised %s table version %" PRIu16
                        " in table at offset 0x%" PRIx32,
                        SectionName.data(), HeaderData.Version, HeaderOffset);
   if (HeaderData.AddrSize != 4 && HeaderData.AddrSize != 8)
-    return createError("%s table at offset 0x%" PRIx32
-                       " has unsupported address size %hhu",
+    return createStringError(errc::not_supported,
+                       "%s table at offset 0x%" PRIx32
+                       " has unsupported address size %" PRIu8,
                        SectionName.data(), HeaderOffset, HeaderData.AddrSize);
   if (HeaderData.SegSize != 0)
-    return createError("%s table at offset 0x%" PRIx32
+    return createStringError(errc::not_supported,
+                       "%s table at offset 0x%" PRIx32
                        " has unsupported segment selector size %" PRIu8,
                        SectionName.data(), HeaderOffset, HeaderData.SegSize);
   if (End < HeaderOffset + sizeof(HeaderData) +
                 HeaderData.OffsetEntryCount * sizeof(uint32_t))
-    return createError(
+    return createStringError(errc::invalid_argument,
         "%s table at offset 0x%" PRIx32 " has more offset entries (%" PRIu32
         ") than there is space for",
         SectionName.data(), HeaderOffset, HeaderData.OffsetEntryCount);
   Data.setAddressSize(HeaderData.AddrSize);
   for (uint32_t I = 0; I < HeaderData.OffsetEntryCount; ++I)
     Offsets.push_back(Data.getU32(OffsetPtr));
   return Error::success();
 }

lib/DebugInfo/DWARF/DWARFUnit.cpp

 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugRnglists.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
 #include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/WithColor.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
 #include <cstdio>
 #include <utility>

 // Parse the rangelist table header, including the optional array of offsets
 // following it (DWARF v5 and later).
 static Expected<DWARFDebugRnglistTable>
 parseRngListTableHeader(DWARFDataExtractor &DA, uint32_t Offset) {
   // TODO: Support DWARF64
   // We are expected to be called with Offset 0 or pointing just past the table
   // header, which is 12 bytes long for DWARF32.
   if (Offset > 0) {
-    if (Offset < 12U) {
-      std::string Buffer;
-      raw_string_ostream Stream(Buffer);
-      Stream << format(
-          "Did not detect a valid range list table with base = 0x%x", Offset);
-      return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
-    }
+    if (Offset < 12U)
+      return createStringError(errc::invalid_argument, "Did not detect a valid"
+                               " range list table with base = 0x%" PRIu32,
+                               Offset);
     Offset -= 12U;
   }
   llvm::DWARFDebugRnglistTable Table;
   if (Error E = Table.extractHeaderAndOffsets(DA, &Offset))
     return std::move(E);
   return Table;
 }
 
if (RngListTable) {
     DWARFDataExtractor RangesData(Context.getDWARFObj(), *RangeSection,
                                   isLittleEndian, RngListTable->getAddrSize());
     auto RangeListOrError = RngListTable->findList(RangesData, Offset);
     if (RangeListOrError)
       return RangeListOrError.get().getAbsoluteRanges(getBaseAddress());
     return RangeListOrError.takeError();
   }
 
-  return make_error<StringError>("missing or invalid range list table",
-                                 inconvertibleErrorCode());
+  return createStringError(errc::invalid_argument,
+                           "missing or invalid range list table");
 }
 
 Expected<DWARFAddressRangesVector>
 DWARFUnit::findRnglistFromIndex(uint32_t Index) {
   if (auto Offset = getRnglistOffset(Index))
     return findRnglistFromOffset(*Offset + RangeSectionBase);
 
-  std::string Buffer;
-  raw_string_ostream Stream(Buffer);
   if (RngListTable)
-    Stream << format("invalid range list table index %d", Index);
+    return createStringError(errc::invalid_argument,
+                             "invalid range list table index %d", Index);
   else
-    Stream << "missing or invalid range list table";
-  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
+    return createStringError(errc::invalid_argument,
+                             "missing or invalid range list table");
 }
 
 void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
   DWARFDie UnitDie = getUnitDIE();
   if (!UnitDie)
     return;
   // First, check if unit DIE describes address ranges for the whole unit.
   auto CUDIERangesOrError = UnitDie.getAddressRanges();