Avoid unnecessary buffer allocation and memcpy for compressed sections.
Previously, we uncompress all compressed sections before doing anything.
That works, and that is conceptually simple, but that could results in
a waste of CPU time and memory if uncompressed sections are then
discarded or just copied to the output buffer.
In particular, if .debug_gnu_pub{names,types} are compressed and if no
-gdb-index option is given, we wasted CPU and memory because we
uncompress them into newly allocated bufers and then memcpy the buffers
to the output buffer. That temporary buffer was redundant.
This patch changes how to uncompress sections. Now, compressed sections
are uncompressed lazily. To do that, `Data` member of `InputSectionBase`
is now hidden from outside, and `data()` accessor automatically expands
an compressed buffer if necessary.
If no one calls `data()`, then `writeTo()` directly uncompresses
compressed data into the output buffer. That eliminates the redundant
memory allocation and redundant memcpy.
This patch significantly reduces memory consumption (20 GiB max RSS to
15 Gib) for an executable whose .debug_gnu_pub{names,types} are in total
5 GiB in an uncompressed form.
Differential Revision: https://reviews.llvm.org/D52917
git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@343979 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/ELF/AArch64ErrataFix.cpp b/ELF/AArch64ErrataFix.cpp
index 27d9726..db83129 100644
--- a/ELF/AArch64ErrataFix.cpp
+++ b/ELF/AArch64ErrataFix.cpp
@@ -356,7 +356,7 @@
}
uint64_t PatchOff = 0;
- const uint8_t *Buf = IS->Data.begin();
+ const uint8_t *Buf = IS->data().begin();
const ulittle32_t *InstBuf = reinterpret_cast<const ulittle32_t *>(Buf + Off);
uint32_t Instr1 = *InstBuf++;
uint32_t Instr2 = *InstBuf++;
@@ -411,7 +411,7 @@
void lld::elf::Patch843419Section::writeTo(uint8_t *Buf) {
// Copy the instruction that we will be replacing with a branch in the
// Patchee Section.
- write32le(Buf, read32le(Patchee->Data.begin() + PatcheeOffset));
+ write32le(Buf, read32le(Patchee->data().begin() + PatcheeOffset));
// Apply any relocation transferred from the original PatcheeSection.
// For a SyntheticSection Buf already has OutSecOff added, but relocateAlloc
@@ -598,7 +598,7 @@
auto DataSym = std::next(CodeSym);
uint64_t Off = (*CodeSym)->Value;
uint64_t Limit =
- (DataSym == MapSyms.end()) ? IS->Data.size() : (*DataSym)->Value;
+ (DataSym == MapSyms.end()) ? IS->data().size() : (*DataSym)->Value;
while (Off < Limit) {
uint64_t StartAddr = IS->getVA(Off);
diff --git a/ELF/DWARF.cpp b/ELF/DWARF.cpp
index fa95555..4c12cfd 100644
--- a/ELF/DWARF.cpp
+++ b/ELF/DWARF.cpp
@@ -30,26 +30,27 @@
for (InputSectionBase *Sec : Obj->getSections()) {
if (!Sec)
continue;
+
if (LLDDWARFSection *M = StringSwitch<LLDDWARFSection *>(Sec->Name)
.Case(".debug_info", &InfoSection)
.Case(".debug_ranges", &RangeSection)
.Case(".debug_line", &LineSection)
.Default(nullptr)) {
- Sec->maybeDecompress();
- M->Data = toStringRef(Sec->Data);
+ M->Data = toStringRef(Sec->data());
M->Sec = Sec;
continue;
}
+
if (Sec->Name == ".debug_abbrev")
- AbbrevSection = toStringRef(Sec->Data);
+ AbbrevSection = toStringRef(Sec->data());
else if (Sec->Name == ".debug_gnu_pubnames")
- GnuPubNamesSection = toStringRef(Sec->Data);
+ GnuPubNamesSection = toStringRef(Sec->data());
else if (Sec->Name == ".debug_gnu_pubtypes")
- GnuPubTypesSection = toStringRef(Sec->Data);
+ GnuPubTypesSection = toStringRef(Sec->data());
else if (Sec->Name == ".debug_str")
- StrSection = toStringRef(Sec->Data);
- if (Sec->Name == ".debug_line_str")
- LineStringSection = toStringRef(Sec->Data);
+ StrSection = toStringRef(Sec->data());
+ else if (Sec->Name == ".debug_line_str")
+ LineStringSection = toStringRef(Sec->data());
}
}
diff --git a/ELF/Driver.cpp b/ELF/Driver.cpp
index b01fd6d..bb80bc2 100644
--- a/ELF/Driver.cpp
+++ b/ELF/Driver.cpp
@@ -1600,14 +1600,12 @@
}
// This adds a .comment section containing a version string. We have to add it
- // before decompressAndMergeSections because the .comment section is a
- // mergeable section.
+ // before mergeSections because the .comment section is a mergeable section.
if (!Config->Relocatable)
InputSections.push_back(createCommentSection());
// Do size optimizations: garbage collection, merging of SHF_MERGE sections
// and identical code folding.
- decompressSections();
splitSections<ELFT>();
markLive<ELFT>();
demoteSharedSymbols<ELFT>();
diff --git a/ELF/EhFrame.cpp b/ELF/EhFrame.cpp
index 20b32c0..95d444b 100644
--- a/ELF/EhFrame.cpp
+++ b/ELF/EhFrame.cpp
@@ -44,7 +44,7 @@
private:
template <class P> void failOn(const P *Loc, const Twine &Msg) {
fatal("corrupted .eh_frame: " + Msg + "\n>>> defined in " +
- IS->getObjMsg((const uint8_t *)Loc - IS->Data.data()));
+ IS->getObjMsg((const uint8_t *)Loc - IS->data().data()));
}
uint8_t readByte();
@@ -59,7 +59,7 @@
}
size_t elf::readEhRecordSize(InputSectionBase *S, size_t Off) {
- return EhReader(S, S->Data.slice(Off)).readEhRecordSize();
+ return EhReader(S, S->data().slice(Off)).readEhRecordSize();
}
// .eh_frame section is a sequence of records. Each record starts with
diff --git a/ELF/ICF.cpp b/ELF/ICF.cpp
index 7c6440a..176c627 100644
--- a/ELF/ICF.cpp
+++ b/ELF/ICF.cpp
@@ -301,7 +301,7 @@
template <class ELFT>
bool ICF<ELFT>::equalsConstant(const InputSection *A, const InputSection *B) {
if (A->NumRelocations != B->NumRelocations || A->Flags != B->Flags ||
- A->getSize() != B->getSize() || A->Data != B->Data)
+ A->getSize() != B->getSize() || A->data() != B->data())
return false;
// If two sections have different output sections, we cannot merge them.
@@ -439,7 +439,7 @@
// Initially, we use hash values to partition sections.
parallelForEach(Sections, [&](InputSection *S) {
// Set MSB to 1 to avoid collisions with non-hash IDs.
- S->Class[0] = xxHash64(S->Data) | (1U << 31);
+ S->Class[0] = xxHash64(S->data()) | (1U << 31);
});
// From now on, sections in Sections vector are ordered so that sections
diff --git a/ELF/InputFiles.cpp b/ELF/InputFiles.cpp
index 8fe8a1e..3980403 100644
--- a/ELF/InputFiles.cpp
+++ b/ELF/InputFiles.cpp
@@ -605,7 +605,7 @@
// as a given section.
static InputSection *toRegularSection(MergeInputSection *Sec) {
return make<InputSection>(Sec->File, Sec->Flags, Sec->Type, Sec->Alignment,
- Sec->Data, Sec->Name);
+ Sec->data(), Sec->Name);
}
template <class ELFT>
diff --git a/ELF/InputSection.cpp b/ELF/InputSection.cpp
index 69d83d0..605d55b 100644
--- a/ELF/InputSection.cpp
+++ b/ELF/InputSection.cpp
@@ -21,7 +21,6 @@
#include "Thunks.h"
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/Memory.h"
-#include "llvm/Object/Decompressor.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/Endian.h"
@@ -64,11 +63,11 @@
StringRef Name, Kind SectionKind)
: SectionBase(SectionKind, Name, Flags, Entsize, Alignment, Type, Info,
Link),
- File(File), Data(Data) {
+ File(File), RawData(Data) {
// In order to reduce memory allocation, we assume that mergeable
// sections are smaller than 4 GiB, which is not an unreasonable
// assumption as of 2017.
- if (SectionKind == SectionBase::Merge && Data.size() > UINT32_MAX)
+ if (SectionKind == SectionBase::Merge && RawData.size() > UINT32_MAX)
error(toString(this) + ": section too large");
NumRelocations = 0;
@@ -80,6 +79,17 @@
if (!isPowerOf2_64(V))
fatal(toString(File) + ": section sh_addralign is not a power of 2");
this->Alignment = V;
+
+ // In ELF, each section can be compressed by zlib, and if compressed,
+ // section name may be mangled by appending "z" (e.g. ".zdebug_info").
+ // If that's the case, demangle section name so that we can handle a
+ // section as if it weren't compressed.
+ if ((Flags & SHF_COMPRESSED) || Name.startswith(".zdebug")) {
+ if (!zlib::isAvailable())
+ error(toString(File) + ": contains a compressed section, " +
+ "but zlib is not available");
+ parseCompressedHeader();
+ }
}
// Drop SHF_GROUP bit unless we are producing a re-linkable object file.
@@ -128,13 +138,25 @@
size_t InputSectionBase::getSize() const {
if (auto *S = dyn_cast<SyntheticSection>(this))
return S->getSize();
+ if (UncompressedSize >= 0)
+ return UncompressedSize;
+ return RawData.size();
+}
- return Data.size();
+void InputSectionBase::uncompress() const {
+ size_t Size = UncompressedSize;
+ UncompressedBuf.reset(new char[Size]);
+
+ if (Error E =
+ zlib::uncompress(toStringRef(RawData), UncompressedBuf.get(), Size))
+ fatal(toString(this) +
+ ": uncompress failed: " + llvm::toString(std::move(E)));
+ RawData = makeArrayRef((uint8_t *)UncompressedBuf.get(), Size);
}
uint64_t InputSectionBase::getOffsetInFile() const {
const uint8_t *FileStart = (const uint8_t *)File->MB.getBufferStart();
- const uint8_t *SecStart = Data.begin();
+ const uint8_t *SecStart = data().begin();
return SecStart - FileStart;
}
@@ -180,34 +202,67 @@
return Sec ? Sec->getParent() : nullptr;
}
-// Decompress section contents if required. Note that this function
-// is called from parallelForEach, so it must be thread-safe.
-void InputSectionBase::maybeDecompress() {
- if (DecompressBuf)
+// When a section is compressed, `RawData` consists with a header followed
+// by zlib-compressed data. This function parses a header to initialize
+// `UncompressedSize` member and remove the header from `RawData`.
+void InputSectionBase::parseCompressedHeader() {
+ // Old-style header
+ if (Name.startswith(".zdebug")) {
+ if (!toStringRef(RawData).startswith("ZLIB")) {
+ error(toString(this) + ": corrupted compressed section header");
+ return;
+ }
+ RawData = RawData.slice(4);
+
+ if (RawData.size() < 8) {
+ error(toString(this) + ": corrupted compressed section header");
+ return;
+ }
+
+ UncompressedSize = read64be(RawData.data());
+ RawData = RawData.slice(8);
+
+ // Restore the original section name.
+ // (e.g. ".zdebug_info" -> ".debug_info")
+ Name = Saver.save("." + Name.substr(2));
return;
- if (!(Flags & SHF_COMPRESSED) && !Name.startswith(".zdebug"))
- return;
+ }
- // Decompress a section.
- Decompressor Dec = check(Decompressor::create(Name, toStringRef(Data),
- Config->IsLE, Config->Is64));
-
- size_t Size = Dec.getDecompressedSize();
- DecompressBuf.reset(new char[Size + Name.size()]());
- if (Error E = Dec.decompress({DecompressBuf.get(), Size}))
- fatal(toString(this) +
- ": decompress failed: " + llvm::toString(std::move(E)));
-
- Data = makeArrayRef((uint8_t *)DecompressBuf.get(), Size);
+ assert(Flags & SHF_COMPRESSED);
Flags &= ~(uint64_t)SHF_COMPRESSED;
- // A section name may have been altered if compressed. If that's
- // the case, restore the original name. (i.e. ".zdebug_" -> ".debug_")
- if (Name.startswith(".zdebug")) {
- DecompressBuf[Size] = '.';
- memcpy(&DecompressBuf[Size + 1], Name.data() + 2, Name.size() - 2);
- Name = StringRef(&DecompressBuf[Size], Name.size() - 1);
+ // New-style 64-bit header
+ if (Config->Is64) {
+ if (RawData.size() < sizeof(Elf64_Chdr)) {
+ error(toString(this) + ": corrupted compressed section");
+ return;
+ }
+
+ auto *Hdr = reinterpret_cast<const Elf64_Chdr *>(RawData.data());
+ if (read32(&Hdr->ch_type) != ELFCOMPRESS_ZLIB) {
+ error(toString(this) + ": unsupported compression type");
+ return;
+ }
+
+ UncompressedSize = read64(&Hdr->ch_size);
+ RawData = RawData.slice(sizeof(*Hdr));
+ return;
}
+
+ // New-style 32-bit header
+ if (RawData.size() < sizeof(Elf32_Chdr)) {
+ error(toString(this) + ": corrupted compressed section");
+ return;
+ }
+
+ auto *Hdr = reinterpret_cast<const Elf32_Chdr *>(RawData.data());
+ if (read32(&Hdr->ch_type) != ELFCOMPRESS_ZLIB) {
+ error(toString(this) + ": unsupported compression type");
+ return;
+ }
+
+ UncompressedSize = read32(&Hdr->ch_size);
+ RawData = RawData.slice(sizeof(*Hdr));
}
InputSection *InputSectionBase::getLinkOrderDep() const {
@@ -381,7 +436,7 @@
}
int64_t Addend = getAddend<ELFT>(Rel);
- const uint8_t *BufLoc = Sec->Data.begin() + Rel.r_offset;
+ const uint8_t *BufLoc = Sec->data().begin() + Rel.r_offset;
if (!RelTy::IsRela)
Addend = Target->getImplicitAddend(BufLoc, Type);
@@ -988,10 +1043,23 @@
return;
}
+ // If this is a compressed section, uncompress section contents directly
+ // to the buffer.
+ if (UncompressedSize >= 0 && !UncompressedBuf) {
+ size_t Size = UncompressedSize;
+ if (Error E = zlib::uncompress(toStringRef(RawData),
+ (char *)(Buf + OutSecOff), Size))
+ fatal(toString(this) +
+ ": uncompress failed: " + llvm::toString(std::move(E)));
+ uint8_t *BufEnd = Buf + OutSecOff + Size;
+ relocate<ELFT>(Buf, BufEnd);
+ return;
+ }
+
// Copy section contents from source object file to output file
// and then apply relocations.
- memcpy(Buf + OutSecOff, Data.data(), Data.size());
- uint8_t *BufEnd = Buf + OutSecOff + Data.size();
+ memcpy(Buf + OutSecOff, data().data(), data().size());
+ uint8_t *BufEnd = Buf + OutSecOff + data().size();
relocate<ELFT>(Buf, BufEnd);
}
@@ -1042,7 +1110,7 @@
template <class ELFT, class RelTy>
void EhInputSection::split(ArrayRef<RelTy> Rels) {
unsigned RelI = 0;
- for (size_t Off = 0, End = Data.size(); Off != End;) {
+ for (size_t Off = 0, End = data().size(); Off != End;) {
size_t Size = readEhRecordSize(this, Off);
Pieces.emplace_back(Off, this, Size, getReloc(Off, Size, Rels, RelI));
// The empty record is the end marker.
@@ -1122,9 +1190,9 @@
assert(Pieces.empty());
if (Flags & SHF_STRINGS)
- splitStrings(Data, Entsize);
+ splitStrings(data(), Entsize);
else
- splitNonStrings(Data, Entsize);
+ splitNonStrings(data(), Entsize);
OffsetMap.reserve(Pieces.size());
for (size_t I = 0, E = Pieces.size(); I != E; ++I)
@@ -1145,7 +1213,7 @@
}
SectionPiece *MergeInputSection::getSectionPiece(uint64_t Offset) {
- if (this->Data.size() <= Offset)
+ if (this->data().size() <= Offset)
fatal(toString(this) + ": offset is outside the section");
// Find a piece starting at a given offset.
diff --git a/ELF/InputSection.h b/ELF/InputSection.h
index c68b7d1..88dcadd 100644
--- a/ELF/InputSection.h
+++ b/ELF/InputSection.h
@@ -115,7 +115,12 @@
return cast_or_null<ObjFile<ELFT>>(File);
}
- ArrayRef<uint8_t> Data;
+ ArrayRef<uint8_t> data() const {
+ if (UncompressedSize >= 0 && !UncompressedBuf)
+ uncompress();
+ return RawData;
+ }
+
uint64_t getOffsetInFile() const;
// True if this section has already been placed to a linker script
@@ -169,11 +174,6 @@
template <class ELFT>
Defined *getEnclosingFunction(uint64_t Offset);
- // Compilers emit zlib-compressed debug sections if the -gz option
- // is given. This function checks if this section is compressed, and
- // if so, decompress in memory.
- void maybeDecompress();
-
// Returns a source location string. Used to construct an error message.
template <class ELFT> std::string getLocation(uint64_t Offset);
std::string getSrcMsg(const Symbol &Sym, uint64_t Offset);
@@ -200,15 +200,21 @@
template <typename T> llvm::ArrayRef<T> getDataAs() const {
- size_t S = Data.size();
+ size_t S = data().size();
assert(S % sizeof(T) == 0);
- return llvm::makeArrayRef<T>((const T *)Data.data(), S / sizeof(T));
+ return llvm::makeArrayRef<T>((const T *)data().data(), S / sizeof(T));
}
-private:
- // A pointer that owns decompressed data if a section is compressed by zlib.
+protected:
+ void parseCompressedHeader();
+ void uncompress() const;
+
+ mutable ArrayRef<uint8_t> RawData;
+
+ // A pointer that owns uncompressed data if a section is compressed by zlib.
// Since the feature is not used often, this is usually a nullptr.
- std::unique_ptr<char[]> DecompressBuf;
+ mutable std::unique_ptr<char[]> UncompressedBuf;
+ int64_t UncompressedSize = -1;
};
// SectionPiece represents a piece of splittable section contents.
@@ -255,8 +261,8 @@
llvm::CachedHashStringRef getData(size_t I) const {
size_t Begin = Pieces[I].InputOff;
size_t End =
- (Pieces.size() - 1 == I) ? Data.size() : Pieces[I + 1].InputOff;
- return {toStringRef(Data.slice(Begin, End - Begin)), Pieces[I].Hash};
+ (Pieces.size() - 1 == I) ? data().size() : Pieces[I + 1].InputOff;
+ return {toStringRef(data().slice(Begin, End - Begin)), Pieces[I].Hash};
}
// Returns the SectionPiece at a given input section offset.
@@ -277,7 +283,9 @@
unsigned FirstRelocation)
: InputOff(Off), Sec(Sec), Size(Size), FirstRelocation(FirstRelocation) {}
- ArrayRef<uint8_t> data() { return {Sec->Data.data() + this->InputOff, Size}; }
+ ArrayRef<uint8_t> data() {
+ return {Sec->data().data() + this->InputOff, Size};
+ }
size_t InputOff;
ssize_t OutputOff = -1;
diff --git a/ELF/MarkLive.cpp b/ELF/MarkLive.cpp
index a8371e2..7264e1c 100644
--- a/ELF/MarkLive.cpp
+++ b/ELF/MarkLive.cpp
@@ -45,7 +45,7 @@
template <class ELFT>
static typename ELFT::uint getAddend(InputSectionBase &Sec,
const typename ELFT::Rel &Rel) {
- return Target->getImplicitAddend(Sec.Data.begin() + Rel.r_offset,
+ return Target->getImplicitAddend(Sec.data().begin() + Rel.r_offset,
Rel.getType(Config->IsMips64EL));
}
diff --git a/ELF/Relocations.cpp b/ELF/Relocations.cpp
index bbb37e3..d7f79c1 100644
--- a/ELF/Relocations.cpp
+++ b/ELF/Relocations.cpp
@@ -582,7 +582,7 @@
if (PairTy == R_MIPS_NONE)
return 0;
- const uint8_t *Buf = Sec.Data.data();
+ const uint8_t *Buf = Sec.data().data();
uint32_t SymIndex = Rel.getSymbol(Config->IsMips64EL);
// To make things worse, paired relocations might not be contiguous in
@@ -610,7 +610,7 @@
if (RelTy::IsRela) {
Addend = getAddend<ELFT>(Rel);
} else {
- const uint8_t *Buf = Sec.Data.data();
+ const uint8_t *Buf = Sec.data().data();
Addend = Target->getImplicitAddend(Buf + Rel.r_offset, Type);
}
@@ -962,7 +962,7 @@
if (maybeReportUndefined(Sym, Sec, Rel.r_offset))
return;
- const uint8_t *RelocatedAddr = Sec.Data.begin() + Rel.r_offset;
+ const uint8_t *RelocatedAddr = Sec.data().begin() + Rel.r_offset;
RelExpr Expr = Target->getRelExpr(Type, Sym, RelocatedAddr);
// Ignore "hint" relocations because they are only markers for relaxation.
diff --git a/ELF/SyntheticSections.cpp b/ELF/SyntheticSections.cpp
index e47c7a9..bc398fe 100644
--- a/ELF/SyntheticSections.cpp
+++ b/ELF/SyntheticSections.cpp
@@ -33,8 +33,8 @@
#include "llvm/ADT/StringExtras.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
-#include "llvm/Object/Decompressor.h"
#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Support/Compression.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/MD5.h"
@@ -105,7 +105,7 @@
Create = true;
std::string Filename = toString(Sec->File);
- const size_t Size = Sec->Data.size();
+ const size_t Size = Sec->data().size();
// Older version of BFD (such as the default FreeBSD linker) concatenate
// .MIPS.abiflags instead of merging. To allow for this case (or potential
// zero padding) we ignore everything after the first Elf_Mips_ABIFlags
@@ -114,7 +114,7 @@
Twine(Size) + " instead of " + Twine(sizeof(Elf_Mips_ABIFlags)));
return nullptr;
}
- auto *S = reinterpret_cast<const Elf_Mips_ABIFlags *>(Sec->Data.data());
+ auto *S = reinterpret_cast<const Elf_Mips_ABIFlags *>(Sec->data().data());
if (S->version != 0) {
error(Filename + ": unexpected .MIPS.abiflags version " +
Twine(S->version));
@@ -177,7 +177,7 @@
Sec->Live = false;
std::string Filename = toString(Sec->File);
- ArrayRef<uint8_t> D = Sec->Data;
+ ArrayRef<uint8_t> D = Sec->data();
while (!D.empty()) {
if (D.size() < sizeof(Elf_Mips_Options)) {
@@ -233,12 +233,12 @@
for (InputSectionBase *Sec : Sections) {
Sec->Live = false;
- if (Sec->Data.size() != sizeof(Elf_Mips_RegInfo)) {
+ if (Sec->data().size() != sizeof(Elf_Mips_RegInfo)) {
error(toString(Sec->File) + ": invalid size of .reginfo section");
return nullptr;
}
- auto *R = reinterpret_cast<const Elf_Mips_RegInfo *>(Sec->Data.data());
+ auto *R = reinterpret_cast<const Elf_Mips_RegInfo *>(Sec->data().data());
Reginfo.ri_gprmask |= R->ri_gprmask;
Sec->getFile<ELFT>()->MipsGp0 = R->ri_gp_value;
};
@@ -2898,12 +2898,6 @@
return make<MergeNoTailSection>(Name, Type, Flags, Alignment);
}
-// Debug sections may be compressed by zlib. Decompress if exists.
-void elf::decompressSections() {
- parallelForEach(InputSections,
- [](InputSectionBase *Sec) { Sec->maybeDecompress(); });
-}
-
template <class ELFT> void elf::splitSections() {
// splitIntoPieces needs to be called on each MergeInputSection
// before calling finalizeContents().
diff --git a/ELF/SyntheticSections.h b/ELF/SyntheticSections.h
index d97a57d..51a0441 100644
--- a/ELF/SyntheticSections.h
+++ b/ELF/SyntheticSections.h
@@ -970,7 +970,6 @@
InputSection *createInterpSection();
MergeInputSection *createCommentSection();
-void decompressSections();
template <class ELFT> void splitSections();
void mergeSections();
diff --git a/test/ELF/compressed-debug-input-err.s b/test/ELF/compressed-debug-input-err.s
index e32ba31..191075e 100644
--- a/test/ELF/compressed-debug-input-err.s
+++ b/test/ELF/compressed-debug-input-err.s
@@ -3,8 +3,8 @@
# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
# RUN: not ld.lld %t.o -o %t.so -shared 2>&1 | FileCheck %s
-## Check we are able to report zlib decompressor errors.
-# CHECK: error: {{.*}}.o:(.zdebug_str): decompress failed: zlib error: Z_DATA_ERROR
+## Check we are able to report zlib uncompress errors.
+# CHECK: error: {{.*}}.o:(.debug_str): uncompress failed: zlib error: Z_DATA_ERROR
.section .zdebug_str,"MS",@progbits,1
.ascii "ZLIB"
diff --git a/test/ELF/relocatable-compressed-input.s b/test/ELF/relocatable-compressed-input.s
index 47d8c11..7ef0cf0 100644
--- a/test/ELF/relocatable-compressed-input.s
+++ b/test/ELF/relocatable-compressed-input.s
@@ -7,7 +7,7 @@
# RUN: ld.lld %t1 -o %t2 -r
# RUN: llvm-readobj -sections -section-data %t2 | FileCheck %s
-## Check we decompress section and remove ".z" prefix specific for zlib-gnu compression.
+## Check we uncompress section and remove ".z" prefix specific for zlib-gnu compression.
# CHECK: Section {
# CHECK: Index:
# CHECK: Name: .debug_str
diff --git a/test/ELF/strip-debug.s b/test/ELF/strip-debug.s
index 8005cfa..f33f1ca 100644
--- a/test/ELF/strip-debug.s
+++ b/test/ELF/strip-debug.s
@@ -12,3 +12,5 @@
.section .debug_Foo,"",@progbits
.section .zdebug_Bar,"",@progbits
+.ascii "ZLIB"
+.quad 0
