diff options
| -rw-r--r-- | lld/lib/ReaderWriter/ELF/SegmentChunks.cpp | 228 |
1 files changed, 123 insertions, 105 deletions
diff --git a/lld/lib/ReaderWriter/ELF/SegmentChunks.cpp b/lld/lib/ReaderWriter/ELF/SegmentChunks.cpp index b915f1ee647..237ef059ebf 100644 --- a/lld/lib/ReaderWriter/ELF/SegmentChunks.cpp +++ b/lld/lib/ReaderWriter/ELF/SegmentChunks.cpp @@ -175,140 +175,158 @@ template <class ELFT> void Segment<ELFT>::assignVirtualAddress(uint64_t addr) { // 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(); - auto si = _sections.begin(); - if (si != _sections.end()) { + 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 (needAlign(*si) || - (this->_ctx.alignSegments() && - _outputMagic != ELFLinkingContext::OutputMagic::NMAGIC && - _outputMagic != ELFLinkingContext::OutputMagic::OMAGIC)) { - startAddr = llvm::RoundUpToAlignment(startAddr, this->_ctx.getPageSize()); - } - // 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(); - } - ++currSection; - ++si; - - for (auto e = _sections.end(); si != e; ++si) { - uint64_t curAddr = curSliceAddress + curSliceSize; - 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; + 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; } - slice->setStart(startSection); - slice->setSections(make_range(startSectionIter, si)); - slice->setMemSize(curSliceSize); - slice->setAlign(sliceAlign); - slice->setVirtualAddr(curSliceAddress); - // Start new slice + // 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; - (*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); + (*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()); + 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) { + // 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 { - curSliceSize = newAddr - curSliceAddress; + 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; } - prevOutputSectionName = curOutputSectionName; - ++currSection; + currSection++; } auto sliceIter = std::find_if(_segmentSlices.begin(), _segmentSlices.end(), [startSection](SegmentSlice<ELFT> *s) -> bool { @@ -319,7 +337,7 @@ template <class ELFT> void Segment<ELFT>::assignVirtualAddress(uint64_t addr) { SegmentSlice<ELFT>(); _segmentSlices.push_back(slice); } else { - slice = *sliceIter; + slice = (*sliceIter); } slice->setStart(startSection); slice->setVirtualAddr(curSliceAddress); |
