1 //===- Relocations.cpp ----------------------------------------------------===//
9 // This file contains platform-independent functions to process relocations.
12 // Simple relocations are easy to handle for the linker. For example,
17 // But not all relocations are that easy to handle. For example, for
23 // ELF defines a large number of complex relocations.
25 // The functions in this file analyze relocations and do whatever needs
29 //  - create new relocations in .dynsym to let the dynamic linker resolve
31 //    relocations can be resolved at link-time)
36 // Note that the functions in this file don't actually apply relocations
38 // It instead stores Relocation objects to InputSection's Relocations
43 #include "Relocations.h"
160 // support any relaxations for TLS relocations so by factoring out MIPS
164 // without dynamic relocations.
170     c.relocations.push_back({expr, type, offset, addend, &sym});  in handleMipsTlsRelocation()
175     c.relocations.push_back({expr, type, offset, addend, &sym});  in handleMipsTlsRelocation()
183 // relocations. The pair of GOT entries created are of the form GOT[e0] Module
187 // Returns the number of relocations processed.
207       c.relocations.push_back({expr, type, offset, addend, &sym});  in handleTlsRelocation()
218   // ARM and RISC-V do not support any relaxations for TLS relocations, however,  in handleTlsRelocation()
219   // we can omit the DTPMOD dynamic relocations and resolve them at link time  in handleTlsRelocation()
232       c.relocations.push_back(  in handleTlsRelocation()
241         in.got->relocations.push_back(  in handleTlsRelocation()
247     c.relocations.push_back({expr, type, offset, addend, &sym});  in handleTlsRelocation()
253     c.relocations.push_back({target->adjustTlsExpr(type, R_RELAX_TLS_LD_TO_LE),  in handleTlsRelocation()
264       in.got->relocations.push_back(  in handleTlsRelocation()
267     c.relocations.push_back({expr, type, offset, addend, &sym});  in handleTlsRelocation()
279           in.got->relocations.push_back(  in handleTlsRelocation()
291           in.got->relocations.push_back(  in handleTlsRelocation()
294       c.relocations.push_back({expr, type, offset, addend, &sym});  in handleTlsRelocation()
301       c.relocations.push_back(  in handleTlsRelocation()
310       c.relocations.push_back(  in handleTlsRelocation()
322     c.relocations.push_back({R_RELAX_TLS_IE_TO_LE, type, offset, addend, &sym});  in handleTlsRelocation()
342     // relocations handle low 16 bits of the address. That allows  in getMipsPairType()
579 // the semantics of copy relocations, assume that you have an exported
619 // MIPS has an odd notion of "paired" relocations to calculate addends.
622 // the two relocations.
643   // To make things worse, paired relocations might not be contiguous in  in computeMipsAddend()
983 // MIPS N32 ABI treats series of successive relocations with the same offset
985 // packs all relocations into the single relocation record. Here we emulate
1005 // relocations, we access offsets in the monotonically increasing
1056     isec->relocations.push_back({expr, type, offsetInSec, addend, sym});  in addRelativeReloc()
1083   // add a static relocation to a Relocations vector so that  in addGotEntry()
1089     in.got->relocations.push_back({expr, target->symbolicRel, off, 0, &sym});  in addGotEntry()
1129 // * Apply relocations, recording which ones require a dynamic reloc.
1130 // * Write the dynamic relocations.
1133 // is needed after applying relocations. If it is, it will go after rw and rx
1150     sec.relocations.push_back({expr, type, offset, addend, &sym});  in processRelocAux()
1166       // MIPS ABI turns using of GOT and dynamic relocations inside out.  in processRelocAux()
1167       // While regular ABI uses dynamic relocations to fill up GOT entries  in processRelocAux()
1170       // relocations against symbols which do not require GOT entries  in processRelocAux()
1171       // creation explicitly, i.e. do not have any GOT-relocations. So if  in processRelocAux()
1187   // When producing an executable, we can perform copy relocations (for  in processRelocAux()
1206       sec.relocations.push_back({expr, type, offset, addend, &sym});  in processRelocAux()
1256       sec.relocations.push_back({expr, type, offset, addend, &sym});  in processRelocAux()
1268           "or pass '-Wl,-z,notext' to allow text relocations in the output" +  in processRelocAux()
1304   // marker relocations, e.g. R_*_NONE and R_ARM_V4BX. Don't error on them.  in scanReloc()
1311   // Ignore R_*_NONE and other marker relocations.  in scanReloc()
1316     warn("using ifunc symbols when text relocations are allowed may produce "  in scanReloc()
1329     // We can separate the small code model relocations into 2 categories:  in scanReloc()
1336     // so sections addressed with small code model relocations come first.  in scanReloc()
1362   // Relax relocations.  in scanReloc()
1399   // Process some TLS relocations, including relaxing TLS relocations.  in scanReloc()
1400   // Note that this function does not handle all TLS relocations.  in scanReloc()
1427         // relocations. In that case dynamic loader applies dynamic  in scanReloc()
1428         // relocations to initialize TLS GOT entries.  in scanReloc()
1448     //   which is usually at the end of .rela.plt. Unlike most relocations in  in scanReloc()
1451     //   IRELATIVE relocs only, GOT-generating relocations can point directly to  in scanReloc()
1456     //   direct (non-GOT-generating, non-PLT-generating) relocations to the  in scanReloc()
1470     //   GOT-generating relocations.  in scanReloc()
1474     //   not require any form of dynamic relocation. To handle these relocations  in scanReloc()
1475     //   correctly, the IRELATIVE relocations are stored in an array which a  in scanReloc()
1534   // Not all relocations end up in Sec.Relocations, but a lot do.  in scanRelocs()
1535   sec.relocations.reserve(rels.size());  in scanRelocs()
1540   // Sort relocations by offset for more efficient searching for  in scanRelocs()
1544     llvm::stable_sort(sec.relocations,  in scanRelocs()
1614 // Relocations.cpp : Framework for creating and placing thunks
1898   // sections. There may be multiple relocations sharing the same (section,  in getThunk()
1940 // Process all relocations from the InputSections that have been assigned
1956 // OutputSections. All relocations that needed a Thunk based on the information
1979           for (Relocation &rel : isec->relocations) {  in createThunks()
2032 // hexagonNeedsTLSSymbol scans for relocations would require a call to
2040           for (Relocation &rel : isec->relocations)  in hexagonNeedsTLSSymbol()
2057           for (Relocation &rel : isec->relocations)  in hexagonTLSSymbolUpdate()