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-rw-r--r--lld/lib/ReaderWriter/ELF/SegmentChunks.h441
1 files changed, 6 insertions, 435 deletions
diff --git a/lld/lib/ReaderWriter/ELF/SegmentChunks.h b/lld/lib/ReaderWriter/ELF/SegmentChunks.h
index cff9530b1b1..2d8c34ee8eb 100644
--- a/lld/lib/ReaderWriter/ELF/SegmentChunks.h
+++ b/lld/lib/ReaderWriter/ELF/SegmentChunks.h
@@ -15,11 +15,9 @@
#include "Writer.h"
#include "lld/Core/range.h"
#include "lld/Core/Writer.h"
-#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Object/ELF.h"
#include "llvm/Support/Allocator.h"
-#include "llvm/Support/Debug.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileOutputBuffer.h"
@@ -70,9 +68,7 @@ public:
void setAlign(uint64_t align) { _alignment = align; }
- static bool compare_slices(SegmentSlice<ELFT> *a, SegmentSlice<ELFT> *b) {
- return a->startSection() < b->startSection();
- }
+ static bool compare_slices(SegmentSlice<ELFT> *a, SegmentSlice<ELFT> *b);
range<SectionIter> sections() { return _sections; }
@@ -148,27 +144,9 @@ public:
_sections.insert(_sections.begin(), c);
}
- /// Finalize the segment before assigning File Offsets / Virtual addresses
-
/// Finalize the segment, before we want to write the segment header
/// information
- void finalize() {
- // We want to finalize the segment values for now only for non loadable
- // segments, since those values are not set in the Layout
- if (_segmentType == llvm::ELF::PT_LOAD)
- return;
- // The size is the difference of the
- // last section to the first section, especially for TLS because
- // the TLS segment contains both .tdata/.tbss
- this->setFileOffset(_sections.front()->fileOffset());
- this->setVirtualAddr(_sections.front()->virtualAddr());
- size_t startFileOffset = _sections.front()->fileOffset();
- size_t startAddr = _sections.front()->virtualAddr();
- for (auto ai : _sections) {
- this->_fsize = ai->fileOffset() + ai->fileSize() - startFileOffset;
- this->_msize = ai->virtualAddr() + ai->memSize() - startAddr;
- }
- }
+ void finalize();
// For LLVM RTTI
static bool classof(const Chunk<ELFT> *c) {
@@ -187,63 +165,18 @@ public:
/// If the content corresponds to Code, this will return Segment::Code
/// If the content corresponds to Data, this will return Segment::Data
/// If the content corresponds to TLS, this will return Segment::TLS
- virtual int getContentType() const {
- int64_t fl = flags();
- switch (_segmentType) {
- case llvm::ELF::PT_LOAD: {
- if (fl && llvm::ELF::PF_X)
- return Chunk<ELFT>::ContentType::Code;
- if (fl && llvm::ELF::PF_W)
- return Chunk<ELFT>::ContentType::Data;
- }
- case llvm::ELF::PT_TLS:
- return Chunk<ELFT>::ContentType::TLS;
- case llvm::ELF::PT_NOTE:
- return Chunk<ELFT>::ContentType::Note;
- default:
- return Chunk<ELFT>::ContentType::Unknown;
- }
- }
+ virtual int getContentType() const;
int pageSize() const { return this->_ctx.getPageSize(); }
-
int rawflags() const { return _atomflags; }
-
- int64_t atomflags() const {
- switch (_atomflags) {
- case DefinedAtom::permUnknown:
- return permUnknown;
- case DefinedAtom::permRWX:
- return permRWX;
- case DefinedAtom::permR_X:
- return permRX;
- case DefinedAtom::permR__:
- return permR;
- case DefinedAtom::permRW_L:
- return permRWL;
- case DefinedAtom::permRW_:
- return permRW;
- case DefinedAtom::perm___:
- default:
- return permNonAccess;
- }
- }
-
+ int64_t atomflags() const;
int64_t numSlices() const { return _segmentSlices.size(); }
-
range<SliceIter> slices() { return _segmentSlices; }
-
Chunk<ELFT> *firstSection() { return _sections[0]; }
private:
-
/// \brief Check if the chunk needs to be aligned
- bool needAlign(Chunk<ELFT> *chunk) const {
- if (chunk->getContentType() == Chunk<ELFT>::ContentType::Data &&
- _outputMagic == ELFLinkingContext::OutputMagic::NMAGIC)
- return true;
- return false;
- }
+ bool needAlign(Chunk<ELFT> *chunk) const;
// Cached value of outputMagic
ELFLinkingContext::OutputMagic _outputMagic;
@@ -300,371 +233,9 @@ public:
/// Finalize the segment, before we want to write the segment header
/// information
- void finalize() {
- // If the segment is of type Program Header, then the values fileOffset
- // and the fileSize need to be picked up from the last section, the first
- // section points to the ELF header and the second chunk points to the
- // actual program headers
- this->setFileOffset(this->_sections.back()->fileOffset());
- this->setVirtualAddr(this->_sections.back()->virtualAddr());
- this->_fsize = this->_sections.back()->fileSize();
- this->_msize = this->_sections.back()->memSize();
- }
+ void finalize();
};
-template <class ELFT>
-Segment<ELFT>::Segment(const ELFLinkingContext &ctx, StringRef name,
- const typename TargetLayout<ELFT>::SegmentType type)
- : Chunk<ELFT>(name, Chunk<ELFT>::Kind::ELFSegment, ctx), _segmentType(type),
- _flags(0), _atomflags(0) {
- this->_alignment = 1;
- this->_fsize = 0;
- _outputMagic = ctx.getOutputMagic();
-}
-
-// This function actually is used, but not in all instantiations of Segment.
-LLVM_ATTRIBUTE_UNUSED
-static DefinedAtom::ContentPermissions toAtomPerms(uint64_t flags) {
- switch (flags & (SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR)) {
- case SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR:
- return DefinedAtom::permRWX;
- case SHF_ALLOC | SHF_EXECINSTR:
- return DefinedAtom::permR_X;
- case SHF_ALLOC:
- return DefinedAtom::permR__;
- case SHF_ALLOC | SHF_WRITE:
- return DefinedAtom::permRW_;
- default:
- return DefinedAtom::permUnknown;
- }
-}
-
-template <class ELFT> void Segment<ELFT>::append(Chunk<ELFT> *chunk) {
- _sections.push_back(chunk);
- Section<ELFT> *section = dyn_cast<Section<ELFT>>(chunk);
- if (!section)
- return;
- if (_flags < section->getFlags())
- _flags |= section->getFlags();
- if (_atomflags < toAtomPerms(_flags))
- _atomflags = toAtomPerms(_flags);
- if (this->_alignment < section->alignment())
- this->_alignment = section->alignment();
-}
-
-template <class ELFT>
-bool Segment<ELFT>::compareSegments(Segment<ELFT> *sega, Segment<ELFT> *segb) {
- int64_t type1 = sega->segmentType();
- int64_t type2 = segb->segmentType();
-
- if (type1 == type2)
- return sega->atomflags() < segb->atomflags();
-
- // The single PT_PHDR segment is required to precede any loadable
- // segment. We simply make it always first.
- if (type1 == llvm::ELF::PT_PHDR)
- return true;
- if (type2 == llvm::ELF::PT_PHDR)
- return false;
-
- // The single PT_INTERP segment is required to precede any loadable
- // segment. We simply make it always second.
- if (type1 == llvm::ELF::PT_INTERP)
- return true;
- if (type2 == llvm::ELF::PT_INTERP)
- return false;
-
- // We then put PT_LOAD segments before any other segments.
- if (type1 == llvm::ELF::PT_LOAD)
- return true;
- if (type2 == llvm::ELF::PT_LOAD)
- return false;
-
- // We put the PT_GNU_RELRO segment last, because that is where the
- // dynamic linker expects to find it
- if (type1 == llvm::ELF::PT_GNU_RELRO)
- return false;
- if (type2 == llvm::ELF::PT_GNU_RELRO)
- return true;
-
- // We put the PT_TLS segment last except for the PT_GNU_RELRO
- // segment, because that is where the dynamic linker expects to find
- if (type1 == llvm::ELF::PT_TLS)
- return false;
- if (type2 == llvm::ELF::PT_TLS)
- return true;
-
- // Otherwise compare the types to establish an arbitrary ordering.
- // FIXME: Should figure out if we should just make all other types compare
- // equal, but if so, we should probably do the same for atom flags and change
- // users of this to use stable_sort.
- return type1 < type2;
-}
-
-template <class ELFT>
-void Segment<ELFT>::assignFileOffsets(uint64_t startOffset) {
- uint64_t fileOffset = startOffset;
- uint64_t curSliceFileOffset = fileOffset;
- bool isDataPageAlignedForNMagic = false;
- bool alignSegments = this->_ctx.alignSegments();
- uint64_t p_align = this->_ctx.getPageSize();
- uint64_t lastVirtualAddress = 0;
-
- this->setFileOffset(startOffset);
- for (auto &slice : slices()) {
- bool isFirstSection = true;
- for (auto section : slice->sections()) {
- // Handle linker script expressions, which may change the offset
- if (!isFirstSection)
- if (auto expr = dyn_cast<ExpressionChunk<ELFT>>(section))
- fileOffset += expr->virtualAddr() - lastVirtualAddress;
- // Align fileoffset to the alignment of the section.
- fileOffset = llvm::RoundUpToAlignment(fileOffset, section->alignment());
- // If the linker outputmagic is set to OutputMagic::NMAGIC, align the Data
- // to a page boundary
- if (isFirstSection &&
- _outputMagic != ELFLinkingContext::OutputMagic::NMAGIC &&
- _outputMagic != ELFLinkingContext::OutputMagic::OMAGIC) {
- // Align to a page only if the output is not
- // OutputMagic::NMAGIC/OutputMagic::OMAGIC
- if (alignSegments)
- fileOffset = llvm::RoundUpToAlignment(fileOffset, p_align);
- else {
- // Align according to ELF spec.
- // in p75, http://www.sco.com/developers/devspecs/gabi41.pdf
- uint64_t virtualAddress = slice->virtualAddr();
- Section<ELFT> *sect = dyn_cast<Section<ELFT>>(section);
- if (sect && sect->isLoadableSection() &&
- ((virtualAddress & (p_align - 1)) !=
- (fileOffset & (p_align - 1))))
- fileOffset = llvm::RoundUpToAlignment(fileOffset, p_align) +
- (virtualAddress % p_align);
- }
- } else if (!isDataPageAlignedForNMagic && needAlign(section)) {
- fileOffset =
- llvm::RoundUpToAlignment(fileOffset, this->_ctx.getPageSize());
- isDataPageAlignedForNMagic = true;
- }
- if (isFirstSection) {
- slice->setFileOffset(fileOffset);
- isFirstSection = false;
- curSliceFileOffset = fileOffset;
- }
- section->setFileOffset(fileOffset);
- fileOffset += section->fileSize();
- lastVirtualAddress = section->virtualAddr() + section->memSize();
- }
- slice->setFileSize(fileOffset - curSliceFileOffset);
- }
- this->setFileSize(fileOffset - startOffset);
-}
-
-/// \brief Assign virtual addresses to the slices
-template <class ELFT> void Segment<ELFT>::assignVirtualAddress(uint64_t addr) {
- int startSection = 0;
- int currSection = 0;
- SectionIter startSectionIter;
-
- // slice align is set to the max alignment of the chunks that are
- // contained in the slice
- uint64_t sliceAlign = 0;
- // Current slice size
- uint64_t curSliceSize = 0;
- // Current Slice File Offset
- uint64_t curSliceAddress = 0;
-
- startSectionIter = _sections.begin();
- startSection = 0;
- bool isFirstSection = true;
- bool isDataPageAlignedForNMagic = false;
- uint64_t startAddr = addr;
- SegmentSlice<ELFT> *slice = nullptr;
- uint64_t tlsStartAddr = 0;
- bool alignSegments = this->_ctx.alignSegments();
- StringRef prevOutputSectionName = StringRef();
-
- for (auto si = _sections.begin(); si != _sections.end(); ++si) {
- // If this is first section in the segment, page align the section start
- // address. The linker needs to align the data section to a page boundary
- // only if NMAGIC is set.
- if (isFirstSection) {
- isFirstSection = false;
- if (alignSegments &&
- _outputMagic != ELFLinkingContext::OutputMagic::NMAGIC &&
- _outputMagic != ELFLinkingContext::OutputMagic::OMAGIC)
- // Align to a page only if the output is not
- // OutputMagic::NMAGIC/OutputMagic::OMAGIC
- startAddr =
- llvm::RoundUpToAlignment(startAddr, this->_ctx.getPageSize());
- else if (!isDataPageAlignedForNMagic && needAlign(*si)) {
- // If the linker outputmagic is set to OutputMagic::NMAGIC, align the
- // Data to a page boundary.
- startAddr =
- llvm::RoundUpToAlignment(startAddr, this->_ctx.getPageSize());
- isDataPageAlignedForNMagic = true;
- }
- // align the startOffset to the section alignment
- uint64_t newAddr = llvm::RoundUpToAlignment(startAddr, (*si)->alignment());
- // Handle linker script expressions, which *may update newAddr* if the
- // expression assigns to "."
- if (auto expr = dyn_cast<ExpressionChunk<ELFT>>(*si))
- expr->evalExpr(newAddr);
- curSliceAddress = newAddr;
- sliceAlign = (*si)->alignment();
- (*si)->setVirtualAddr(curSliceAddress);
-
- // Handle TLS.
- if (auto section = dyn_cast<Section<ELFT>>(*si)) {
- if (section->getSegmentType() == llvm::ELF::PT_TLS) {
- tlsStartAddr =
- llvm::RoundUpToAlignment(tlsStartAddr, (*si)->alignment());
- section->assignVirtualAddress(tlsStartAddr);
- tlsStartAddr += (*si)->memSize();
- } else {
- section->assignVirtualAddress(newAddr);
- }
- }
- // TBSS section is special in that it doesn't contribute to memory of any
- // segment. If we see a tbss section, don't add memory size to addr The
- // fileOffset is automatically taken care of since TBSS section does not
- // end up using file size
- if ((*si)->order() != TargetLayout<ELFT>::ORDER_TBSS)
- curSliceSize = (*si)->memSize();
- } else {
- uint64_t curAddr = curSliceAddress + curSliceSize;
- if (!isDataPageAlignedForNMagic && needAlign(*si)) {
- // If the linker outputmagic is set to OutputMagic::NMAGIC, align the
- // Data
- // to a page boundary
- curAddr = llvm::RoundUpToAlignment(curAddr, this->_ctx.getPageSize());
- isDataPageAlignedForNMagic = true;
- }
- uint64_t newAddr = llvm::RoundUpToAlignment(curAddr, (*si)->alignment());
- // Handle linker script expressions, which *may update newAddr* if the
- // expression assigns to "."
- if (auto expr = dyn_cast<ExpressionChunk<ELFT>>(*si))
- expr->evalExpr(newAddr);
- Section<ELFT> *sec = dyn_cast<Section<ELFT>>(*si);
- StringRef curOutputSectionName;
- if (sec)
- curOutputSectionName = sec->outputSectionName();
- else {
- // If this is a linker script expression, propagate the name of the
- // previous section instead
- if (isa<ExpressionChunk<ELFT>>(*si))
- curOutputSectionName = prevOutputSectionName;
- else
- curOutputSectionName = (*si)->name();
- }
- bool autoCreateSlice = true;
- if (curOutputSectionName == prevOutputSectionName)
- autoCreateSlice = false;
- // If the newAddress computed is more than a page away, let's create
- // a separate segment, so that memory is not used up while running.
- // Dont create a slice, if the new section falls in the same output
- // section as the previous section.
- if (autoCreateSlice && ((newAddr - curAddr) > this->_ctx.getPageSize()) &&
- (_outputMagic != ELFLinkingContext::OutputMagic::NMAGIC &&
- _outputMagic != ELFLinkingContext::OutputMagic::OMAGIC)) {
- auto sliceIter =
- std::find_if(_segmentSlices.begin(), _segmentSlices.end(),
- [startSection](SegmentSlice<ELFT> *s) -> bool {
- return s->startSection() == startSection;
- });
- if (sliceIter == _segmentSlices.end()) {
- slice = new (_segmentAllocate.Allocate<SegmentSlice<ELFT>>())
- SegmentSlice<ELFT>();
- _segmentSlices.push_back(slice);
- } else {
- slice = (*sliceIter);
- }
- slice->setStart(startSection);
- slice->setSections(make_range(startSectionIter, si));
- slice->setMemSize(curSliceSize);
- slice->setAlign(sliceAlign);
- slice->setVirtualAddr(curSliceAddress);
- // Start new slice
- curSliceAddress = newAddr;
- (*si)->setVirtualAddr(curSliceAddress);
- startSectionIter = si;
- startSection = currSection;
- if (auto section = dyn_cast<Section<ELFT>>(*si))
- section->assignVirtualAddress(newAddr);
- curSliceSize = newAddr - curSliceAddress + (*si)->memSize();
- sliceAlign = (*si)->alignment();
- } else {
- if (sliceAlign < (*si)->alignment())
- sliceAlign = (*si)->alignment();
- (*si)->setVirtualAddr(newAddr);
- // Handle TLS.
- if (auto section = dyn_cast<Section<ELFT>>(*si)) {
- if (section->getSegmentType() == llvm::ELF::PT_TLS) {
- tlsStartAddr =
- llvm::RoundUpToAlignment(tlsStartAddr, (*si)->alignment());
- section->assignVirtualAddress(tlsStartAddr);
- tlsStartAddr += (*si)->memSize();
- } else {
- section->assignVirtualAddress(newAddr);
- }
- }
- // TBSS section is special in that it doesn't contribute to memory of
- // any segment. If we see a tbss section, don't add memory size to addr
- // The fileOffset is automatically taken care of since TBSS section does
- // not end up using file size.
- if ((*si)->order() != TargetLayout<ELFT>::ORDER_TBSS)
- curSliceSize = newAddr - curSliceAddress + (*si)->memSize();
- else
- curSliceSize = newAddr - curSliceAddress;
- }
- prevOutputSectionName = curOutputSectionName;
- }
- currSection++;
- }
- auto sliceIter = std::find_if(_segmentSlices.begin(), _segmentSlices.end(),
- [startSection](SegmentSlice<ELFT> *s) -> bool {
- return s->startSection() == startSection;
- });
- if (sliceIter == _segmentSlices.end()) {
- slice = new (_segmentAllocate.Allocate<SegmentSlice<ELFT>>())
- SegmentSlice<ELFT>();
- _segmentSlices.push_back(slice);
- } else {
- slice = (*sliceIter);
- }
- slice->setStart(startSection);
- slice->setVirtualAddr(curSliceAddress);
- slice->setMemSize(curSliceSize);
- slice->setSections(make_range(startSectionIter, _sections.end()));
- slice->setAlign(sliceAlign);
-
- // Set the segment memory size and the virtual address.
- this->setMemSize(curSliceAddress - startAddr + curSliceSize);
- this->setVirtualAddr(curSliceAddress);
- std::stable_sort(_segmentSlices.begin(), _segmentSlices.end(),
- SegmentSlice<ELFT>::compare_slices);
-}
-
-// Write the Segment
-template <class ELFT>
-void Segment<ELFT>::write(ELFWriter *writer, TargetLayout<ELFT> &layout,
- llvm::FileOutputBuffer &buffer) {
- for (auto slice : slices())
- for (auto section : slice->sections())
- section->write(writer, layout, buffer);
-}
-
-template<class ELFT>
-int64_t
-Segment<ELFT>::flags() const {
- int64_t fl = 0;
- if (_flags & llvm::ELF::SHF_ALLOC)
- fl |= llvm::ELF::PF_R;
- if (_flags & llvm::ELF::SHF_WRITE)
- fl |= llvm::ELF::PF_W;
- if (_flags & llvm::ELF::SHF_EXECINSTR)
- fl |= llvm::ELF::PF_X;
- return fl;
-}
} // end namespace elf
} // end namespace lld
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