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[llvm-objcopy] Add objcopy:🧝:Object::allocSections to simplify loops on SHF_ALLOC sections

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Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D67142

llvm-svn: 370860
This commit is contained in:
Fangrui Song 2019-09-04 09:35:32 +00:00
parent 9bae231558
commit fe2da4e5ed
2 changed files with 21 additions and 22 deletions
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28
llvm/tools/llvm-objcopy/ELF/Object.cpp
View File

@ -2101,23 +2101,19 @@ template <class ELFT> Error ELFWriter<ELFT>::finalize() {
} }
Error BinaryWriter::write() { Error BinaryWriter::write() {
for (const SectionBase &Sec : Obj.sections()) for (const SectionBase &Sec : Obj.allocSections())
if (Sec.Flags & SHF_ALLOC) Sec.accept(*SecWriter);
Sec.accept(*SecWriter);
return Buf.commit(); return Buf.commit();
} }
Error BinaryWriter::finalize() { Error BinaryWriter::finalize() {
// TODO: Create a filter range to construct OrderedSegments from so that this
// code can be deduped with assignOffsets above. This should also solve the
// todo below for LayoutSections.
// We need a temporary list of segments that has a special order to it // We need a temporary list of segments that has a special order to it
// so that we know that anytime ->ParentSegment is set that segment has // so that we know that anytime ->ParentSegment is set that segment has
// already had it's offset properly set. We only want to consider the segments // already had it's offset properly set. We only want to consider the segments
// that will affect layout of allocated sections so we only add those. // that will affect layout of allocated sections so we only add those.
std::vector<Segment *> OrderedSegments; std::vector<Segment *> OrderedSegments;
for (const SectionBase &Sec : Obj.sections()) for (const SectionBase &Sec : Obj.allocSections())
if ((Sec.Flags & SHF_ALLOC) != 0 && Sec.ParentSegment != nullptr) if (Sec.ParentSegment != nullptr)
OrderedSegments.push_back(Sec.ParentSegment); OrderedSegments.push_back(Sec.ParentSegment);
// For binary output, we're going to use physical addresses instead of // For binary output, we're going to use physical addresses instead of
@ -2161,24 +2157,16 @@ Error BinaryWriter::finalize() {
} }
} }
// TODO: generalize layoutSections to take a range. Pass a special range layoutSections(Obj.allocSections(), Offset);
// constructed from an iterator that skips values for which a predicate does
// not hold. Then pass such a range to layoutSections instead of constructing
// AllocatedSections here.
std::vector<SectionBase *> AllocatedSections;
for (SectionBase &Sec : Obj.sections())
if (Sec.Flags & SHF_ALLOC)
AllocatedSections.push_back(&Sec);
layoutSections(make_pointee_range(AllocatedSections), Offset);
// Now that every section has been laid out we just need to compute the total // Now that every section has been laid out we just need to compute the total
// file size. This might not be the same as the offset returned by // file size. This might not be the same as the offset returned by
// layoutSections, because we want to truncate the last segment to the end of // layoutSections, because we want to truncate the last segment to the end of
// its last section, to match GNU objcopy's behaviour. // its last section, to match GNU objcopy's behaviour.
TotalSize = 0; TotalSize = 0;
for (SectionBase *Sec : AllocatedSections) for (const SectionBase &Sec : Obj.allocSections())
if (Sec->Type != SHT_NOBITS) if (Sec.Type != SHT_NOBITS)
TotalSize = std::max(TotalSize, Sec->Offset + Sec->Size); TotalSize = std::max(TotalSize, Sec.Offset + Sec.Size);
if (Error E = Buf.allocate(TotalSize)) if (Error E = Buf.allocate(TotalSize))
return E; return E;

15
llvm/tools/llvm-objcopy/ELF/Object.h
View File

@ -57,8 +57,8 @@ public:
: Sections(Secs) {} : Sections(Secs) {}
SectionTableRef(const SectionTableRef &) = default; SectionTableRef(const SectionTableRef &) = default;
iterator begin() { return iterator(Sections.data()); } iterator begin() const { return iterator(Sections.data()); }
iterator end() { return iterator(Sections.data() + Sections.size()); } iterator end() const { return iterator(Sections.data() + Sections.size()); }
size_t size() const { return Sections.size(); } size_t size() const { return Sections.size(); }
SectionBase *getSection(uint32_t Index, Twine ErrMsg); SectionBase *getSection(uint32_t Index, Twine ErrMsg);
@ -994,6 +994,10 @@ private:
std::vector<SegPtr> Segments; std::vector<SegPtr> Segments;
std::vector<SecPtr> RemovedSections; std::vector<SecPtr> RemovedSections;
static bool sectionIsAlloc(const SectionBase &Sec) {
return Sec.Flags & ELF::SHF_ALLOC;
};
public: public:
template <class T> template <class T>
using Range = iterator_range< using Range = iterator_range<
@ -1032,6 +1036,13 @@ public:
ConstRange<SectionBase> sections() const { ConstRange<SectionBase> sections() const {
return make_pointee_range(Sections); return make_pointee_range(Sections);
} }
iterator_range<
filter_iterator<pointee_iterator<std::vector<SecPtr>::const_iterator>,
decltype(&sectionIsAlloc)>>
allocSections() const {
return make_filter_range(make_pointee_range(Sections), sectionIsAlloc);
}
SectionBase *findSection(StringRef Name) { SectionBase *findSection(StringRef Name) {
auto SecIt = auto SecIt =
find_if(Sections, [&](const SecPtr &Sec) { return Sec->Name == Name; }); find_if(Sections, [&](const SecPtr &Sec) { return Sec->Name == Name; });