1 //===- BranchIslandFactory.cpp --------------------------------------------===// 2 // 3 // The MCLinker Project 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 #include <mcld/LD/BranchIslandFactory.h> 10 #include <mcld/Fragment/Fragment.h> 11 #include <mcld/LD/LDSection.h> 12 #include <mcld/LD/SectionData.h> 13 #include <mcld/Module.h> 14 15 using namespace mcld; 16 17 //===----------------------------------------------------------------------===// 18 // BranchIslandFactory 19 //===----------------------------------------------------------------------===// 20 21 /// ctor 22 /// @param pMaxFwdBranchRange - the max forward branch range of the target 23 /// @param pMaxBwdBranchRange - the max backward branch range of the target 24 /// @param pMaxIslandSize - the predefined value for the max size of a island 25 BranchIslandFactory::BranchIslandFactory(int64_t pMaxFwdBranchRange, 26 int64_t pMaxBwdBranchRange, 27 size_t pMaxIslandSize) 28 : GCFactory<BranchIsland, 0>(1u), // magic number 29 m_MaxFwdBranchRange(pMaxFwdBranchRange - pMaxIslandSize), 30 m_MaxBwdBranchRange(pMaxBwdBranchRange + pMaxIslandSize), 31 m_MaxIslandSize(pMaxIslandSize) 32 { 33 } 34 35 BranchIslandFactory::~BranchIslandFactory() 36 { 37 } 38 39 /// group - group fragments and create islands when needed 40 /// @param pSectionData - the SectionData holds fragments need to be grouped 41 void BranchIslandFactory::group(Module& pModule) 42 { 43 /* FIXME: Currently only support relaxing .text section! */ 44 LDSection* text = pModule.getSection(".text"); 45 if (text != NULL && text->hasSectionData()) { 46 SectionData& sd = *text->getSectionData(); 47 uint64_t group_end = m_MaxFwdBranchRange; 48 for (SectionData::iterator it = sd.begin(), ie = sd.end(); it != ie; ++it) { 49 if ((*it).getOffset() + (*it).size() > group_end) { 50 Fragment* frag = (*it).getPrevNode(); 51 while (frag != NULL && frag->getKind() == Fragment::Alignment) { 52 frag = frag->getPrevNode(); 53 } 54 if (frag != NULL) { 55 produce(*frag); 56 group_end = (*it).getOffset() + m_MaxFwdBranchRange; 57 } 58 } 59 } 60 if (getIslands(sd.back()).first == NULL) 61 produce(sd.back()); 62 } 63 } 64 65 /// produce - produce a island for the given fragment 66 /// @param pFragment - the fragment needs a branch island 67 BranchIsland* BranchIslandFactory::produce(Fragment& pFragment) 68 { 69 BranchIsland *island = allocate(); 70 new (island) BranchIsland(pFragment, // entry fragment to the island 71 m_MaxIslandSize, // the max size of the island 72 size() - 1u); // index in the island factory 73 return island; 74 } 75 76 /// getIsland - find fwd and bwd islands for the fragment 77 /// @param pFragment - the fragment needs a branch island 78 std::pair<BranchIsland*, BranchIsland*> 79 BranchIslandFactory::getIslands(const Fragment& pFragment) 80 { 81 BranchIsland* fwd = NULL; 82 BranchIsland* bwd = NULL; 83 for (iterator it = begin(), ie = end(), prev = ie; it != ie; 84 prev = it, ++it) { 85 if ((pFragment.getOffset() < (*it).offset()) && 86 ((pFragment.getOffset() + m_MaxFwdBranchRange) >= (*it).offset())) { 87 88 fwd = &*it; 89 90 if (prev != ie) { 91 int64_t bwd_off = (int64_t)pFragment.getOffset() + m_MaxBwdBranchRange; 92 if ((pFragment.getOffset() > (*prev).offset()) && 93 (bwd_off <= (int64_t) (*prev).offset())) { 94 bwd = &*prev; 95 } 96 } 97 break; 98 } 99 } 100 return std::make_pair(fwd, bwd); 101 } 102
