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[ELFObject] Added conditions to print removed symbols and removed sections #124692

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[ELFObject] Added conditions to print removed symbols and removed sections #124692

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718edfe
[ELFObject] Added dbgs() statement in removeSections()
kshitijvp Jan 27, 2025
02fb5c0
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kshitijvp Feb 8, 2025
76ccb57
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kshitijvp Mar 11, 2025
378fadb
Informal Change(Testing)
kshitijvp Apr 12, 2025
ac90408
Delete llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
kshitijvp May 16, 2025
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4 changes: 4 additions & 0 deletions llvm/docs/CommandGuide/llvm-objcopy.rst
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Expand Up @@ -178,6 +178,10 @@ multiple file formats.
specified ``<flag>`` values. Can be specified multiple times to update multiple
sections.

.. option:: --verbose

List all object files modified.

Supported flag names are `alloc`, `load`, `noload`, `readonly`, `exclude`,
`debug`, `code`, `data`, `rom`, `share`, `contents`, `merge`, `strings`, and
`large`. Not all flags are meaningful for all object file formats or target
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1 change: 1 addition & 0 deletions llvm/include/llvm/ObjCopy/CommonConfig.h
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Expand Up @@ -274,6 +274,7 @@ struct CommonConfig {
bool StripNonAlloc = false;
bool StripSections = false;
bool StripUnneeded = false;
bool Verbose = false;
bool Weaken = false;
bool DecompressDebugSections = false;

Expand Down
5 changes: 3 additions & 2 deletions llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
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Expand Up @@ -546,7 +546,7 @@ static Error replaceAndRemoveSections(const CommonConfig &Config,
};
}

if (Error E = Obj.removeSections(ELFConfig.AllowBrokenLinks, RemovePred))
if (Error E = Obj.removeSections(ELFConfig.AllowBrokenLinks, RemovePred, Config.Verbose))
return E;

if (Error E = Obj.compressOrDecompressSections(Config))
Expand Down Expand Up @@ -782,6 +782,7 @@ static Error verifyNoteSection(StringRef Name, endianness Endianness,
// system. The only priority is that keeps/copies overrule removes.
static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
ElfType OutputElfType, Object &Obj) {
Obj.VerboseOutput = Config.Verbose;
if (Config.OutputArch) {
Obj.Machine = Config.OutputArch->EMachine;
Obj.OSABI = Config.OutputArch->OSABI;
Expand All @@ -790,7 +791,7 @@ static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
if (!Config.SplitDWO.empty() && Config.ExtractDWO) {
return Obj.removeSections(
ELFConfig.AllowBrokenLinks,
[&Obj](const SectionBase &Sec) { return onlyKeepDWOPred(Obj, Sec); });
[&Obj](const SectionBase &Sec) { return onlyKeepDWOPred(Obj, Sec); }, Config.Verbose);
}

// Dump sections before add/remove for compatibility with GNU objcopy.
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30 changes: 21 additions & 9 deletions llvm/lib/ObjCopy/ELF/ELFObject.cpp
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Expand Up @@ -766,14 +766,20 @@ Error SymbolTableSection::removeSymbols(
function_ref<bool(const Symbol &)> ToRemove) {
Symbols.erase(
std::remove_if(std::begin(Symbols) + 1, std::end(Symbols),
[ToRemove](const SymPtr &Sym) { return ToRemove(*Sym); }),
std::end(Symbols));
[&](const SymPtr &Sym) {
if (ToRemove(*Sym)) {
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@jh7370 jh7370 Feb 19, 2025

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There's no need for the braces here (see other comment about coding standards).

if(VerboseOutput)
outs() << "Symbols Removed:" << Sym->Name<< "\n";
return true;
}
return false;
}));

auto PrevSize = Size;
Size = Symbols.size() * EntrySize;
if (Size < PrevSize)
IndicesChanged = true;
assignIndices();
return Error::success();
}

void SymbolTableSection::replaceSectionReferences(
Expand Down Expand Up @@ -2195,7 +2201,7 @@ Error Object::updateSectionData(SectionBase &S, ArrayRef<uint8_t> Data) {
}

Error Object::removeSections(
bool AllowBrokenLinks, std::function<bool(const SectionBase &)> ToRemove) {
bool AllowBrokenLinks, std::function<bool(const SectionBase &)> ToRemove, bool VerboseOutput) {

auto Iter = std::stable_partition(
std::begin(Sections), std::end(Sections), [=](const SecPtr &Sec) {
Expand Down Expand Up @@ -2230,6 +2236,9 @@ Error Object::removeSections(
for (auto &RemoveSec : make_range(Iter, std::end(Sections))) {
for (auto &Segment : Segments)
Segment->removeSection(RemoveSec.get());
if (VerboseOutput) {
outs() << "removed section: " << (RemoveSec.get()->Name);
}
RemoveSec->onRemove();
RemoveSections.insert(RemoveSec.get());
}
Expand Down Expand Up @@ -2273,17 +2282,20 @@ Error Object::replaceSections(

if (Error E = removeSections(
/*AllowBrokenLinks=*/false,
[=](const SectionBase &Sec) { return FromTo.count(&Sec) > 0; }))
[=](const SectionBase &Sec) { return FromTo.count(&Sec) > 0; }, false))
return E;
llvm::sort(Sections, SectionIndexLess);
return Error::success();
}

Error Object::removeSymbols(function_ref<bool(const Symbol &)> ToRemove) {
if (SymbolTable)
for (const SecPtr &Sec : Sections)
if (SymbolTable){
for (const SecPtr &Sec : Sections){
if (Error E = Sec->removeSymbols(ToRemove))
return E;
outs() << "removed symbols:" << Sec->Name;
}
}
return Error::success();
}

Expand Down Expand Up @@ -2570,7 +2582,7 @@ static Error removeUnneededSections(Object &Obj) {
: Obj.SymbolTable->getStrTab();
return Obj.removeSections(false, [&](const SectionBase &Sec) {
return &Sec == Obj.SymbolTable || &Sec == StrTab;
});
}, false);
}

template <class ELFT> Error ELFWriter<ELFT>::finalize() {
Expand Down Expand Up @@ -2624,7 +2636,7 @@ template <class ELFT> Error ELFWriter<ELFT>::finalize() {
if (Error E = Obj.removeSections(false /*AllowBrokenLinks*/,
[this](const SectionBase &Sec) {
return &Sec == Obj.SectionIndexTable;
}))
}, false))
return E;
}
}
Expand Down
6 changes: 5 additions & 1 deletion llvm/lib/ObjCopy/ELF/ELFObject.h
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Expand Up @@ -814,6 +814,8 @@ class SymbolTableSection : public SectionBase {
void setStrTab(StringTableSection *StrTab) { SymbolNames = StrTab; }
void assignIndices();

private:
bool VerboseOutput;
protected:
std::vector<std::unique_ptr<Symbol>> Symbols;
StringTableSection *SymbolNames = nullptr;
Expand Down Expand Up @@ -856,6 +858,7 @@ class SymbolTableSection : public SectionBase {
static bool classof(const SectionBase *S) {
return S->OriginalType == ELF::SHT_SYMTAB;
}
bool getVerboseOutput() { return VerboseOutput; }
};

struct Relocation {
Expand Down Expand Up @@ -1195,6 +1198,7 @@ class Object {
uint32_t Flags;

bool HadShdrs = true;
bool VerboseOutput;
bool MustBeRelocatable = false;
StringTableSection *SectionNames = nullptr;
SymbolTableSection *SymbolTable = nullptr;
Expand Down Expand Up @@ -1224,7 +1228,7 @@ class Object {
ConstRange<Segment> segments() const { return make_pointee_range(Segments); }

Error removeSections(bool AllowBrokenLinks,
std::function<bool(const SectionBase &)> ToRemove);
std::function<bool(const SectionBase &)> ToRemove, bool VerboseOutput);
Error compressOrDecompressSections(const CommonConfig &Config);
Error replaceSections(const DenseMap<SectionBase *, SectionBase *> &FromTo);
Error removeSymbols(function_ref<bool(const Symbol &)> ToRemove);
Expand Down
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