diff options
Diffstat (limited to 'contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp')
-rw-r--r-- | contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp | 462 |
1 files changed, 391 insertions, 71 deletions
diff --git a/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp index d4d84d3..f2c69fc 100644 --- a/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp +++ b/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp @@ -22,7 +22,7 @@ #include "llvm/ADT/Triple.h" #include "llvm/ExecutionEngine/ObjectBuffer.h" #include "llvm/ExecutionEngine/ObjectImage.h" -#include "llvm/Object/ELF.h" +#include "llvm/Object/ELFObjectFile.h" #include "llvm/Object/ObjectFile.h" #include "llvm/Support/ELF.h" using namespace llvm; @@ -151,12 +151,31 @@ void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, namespace llvm { -StringRef RuntimeDyldELF::getEHFrameSection() { - for (int i = 0, e = Sections.size(); i != e; ++i) { - if (Sections[i].Name == ".eh_frame") - return StringRef((const char*)Sections[i].Address, Sections[i].Size); +void RuntimeDyldELF::registerEHFrames() { + if (!MemMgr) + return; + for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { + SID EHFrameSID = UnregisteredEHFrameSections[i]; + uint8_t *EHFrameAddr = Sections[EHFrameSID].Address; + uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress; + size_t EHFrameSize = Sections[EHFrameSID].Size; + MemMgr->registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); + RegisteredEHFrameSections.push_back(EHFrameSID); } - return StringRef(); + UnregisteredEHFrameSections.clear(); +} + +void RuntimeDyldELF::deregisterEHFrames() { + if (!MemMgr) + return; + for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) { + SID EHFrameSID = RegisteredEHFrameSections[i]; + uint8_t *EHFrameAddr = Sections[EHFrameSID].Address; + uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress; + size_t EHFrameSize = Sections[EHFrameSID].Size; + MemMgr->deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); + } + RegisteredEHFrameSections.clear(); } ObjectImage *RuntimeDyldELF::createObjectImage(ObjectBuffer *Buffer) { @@ -202,7 +221,8 @@ void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, uint64_t Offset, uint64_t Value, uint32_t Type, - int64_t Addend) { + int64_t Addend, + uint64_t SymOffset) { switch (Type) { default: llvm_unreachable("Relocation type not implemented yet!"); @@ -227,6 +247,21 @@ void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, << " at " << format("%p\n",Target)); break; } + case ELF::R_X86_64_GOTPCREL: { + // findGOTEntry returns the 'G + GOT' part of the relocation calculation + // based on the load/target address of the GOT (not the current/local addr). + uint64_t GOTAddr = findGOTEntry(Value, SymOffset); + uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); + uint64_t FinalAddress = Section.LoadAddress + Offset; + // The processRelocationRef method combines the symbol offset and the addend + // and in most cases that's what we want. For this relocation type, we need + // the raw addend, so we subtract the symbol offset to get it. + int64_t RealOffset = GOTAddr + Addend - SymOffset - FinalAddress; + assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN); + int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); + *Target = TruncOffset; + break; + } case ELF::R_X86_64_PC32: { // Get the placeholder value from the generated object since // a previous relocation attempt may have overwritten the loaded version @@ -240,6 +275,16 @@ void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, *Target = TruncOffset; break; } + case ELF::R_X86_64_PC64: { + // Get the placeholder value from the generated object since + // a previous relocation attempt may have overwritten the loaded version + uint64_t *Placeholder = reinterpret_cast<uint64_t*>(Section.ObjAddress + + Offset); + uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset); + uint64_t FinalAddress = Section.LoadAddress + Offset; + *Target = *Placeholder + Value + Addend - FinalAddress; + break; + } } } @@ -302,9 +347,9 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, *TargetPtr = Value + Addend; break; } - case ELF::R_AARCH64_PREL32: { // test-shift.ll (.eh_frame) + case ELF::R_AARCH64_PREL32: { uint64_t Result = Value + Addend - FinalAddress; - assert(static_cast<int64_t>(Result) >= INT32_MIN && + assert(static_cast<int64_t>(Result) >= INT32_MIN && static_cast<int64_t>(Result) <= UINT32_MAX); *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU); break; @@ -316,41 +361,62 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, uint64_t BranchImm = Value + Addend - FinalAddress; // "Check that -2^27 <= result < 2^27". - assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) && + assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) && static_cast<int64_t>(BranchImm) < (1LL << 27)); + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xfc000000U; // Immediate goes in bits 25:0 of B and BL. *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2; break; } case ELF::R_AARCH64_MOVW_UABS_G3: { uint64_t Result = Value + Addend; + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xffe0001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= Result >> (48 - 5); - // Shift is "lsl #48", in bits 22:21 - *TargetPtr |= 3 << 21; + // Shift must be "lsl #48", in bits 22:21 + assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation"); break; } case ELF::R_AARCH64_MOVW_UABS_G2_NC: { uint64_t Result = Value + Addend; + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xffe0001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5)); - // Shift is "lsl #32", in bits 22:21 - *TargetPtr |= 2 << 21; + // Shift must be "lsl #32", in bits 22:21 + assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation"); break; } case ELF::R_AARCH64_MOVW_UABS_G1_NC: { uint64_t Result = Value + Addend; + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xffe0001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5)); - // Shift is "lsl #16", in bits 22:21 - *TargetPtr |= 1 << 21; + // Shift must be "lsl #16", in bits 22:2 + assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation"); break; } case ELF::R_AARCH64_MOVW_UABS_G0_NC: { uint64_t Result = Value + Addend; + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xffe0001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= ((Result & 0xffffU) << 5); - // Shift is "lsl #0", in bits 22:21. No action needed. + // Shift must be "lsl #0", in bits 22:21. + assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation"); break; } } @@ -362,6 +428,8 @@ void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, uint32_t Type, int32_t Addend) { // TODO: Add Thumb relocations. + uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress + + Offset); uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset); uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF); Value += Addend; @@ -380,44 +448,51 @@ void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, // Write a 32bit value to relocation address, taking into account the // implicit addend encoded in the target. - case ELF::R_ARM_TARGET1 : - case ELF::R_ARM_ABS32 : - *TargetPtr += Value; + case ELF::R_ARM_TARGET1: + case ELF::R_ARM_ABS32: + *TargetPtr = *Placeholder + Value; break; - // Write first 16 bit of 32 bit value to the mov instruction. // Last 4 bit should be shifted. - case ELF::R_ARM_MOVW_ABS_NC : + case ELF::R_ARM_MOVW_ABS_NC: // We are not expecting any other addend in the relocation address. // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2 // non-contiguous fields. - assert((*TargetPtr & 0x000F0FFF) == 0); + assert((*Placeholder & 0x000F0FFF) == 0); Value = Value & 0xFFFF; - *TargetPtr |= Value & 0xFFF; + *TargetPtr = *Placeholder | (Value & 0xFFF); *TargetPtr |= ((Value >> 12) & 0xF) << 16; break; - // Write last 16 bit of 32 bit value to the mov instruction. // Last 4 bit should be shifted. - case ELF::R_ARM_MOVT_ABS : + case ELF::R_ARM_MOVT_ABS: // We are not expecting any other addend in the relocation address. // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC. - assert((*TargetPtr & 0x000F0FFF) == 0); + assert((*Placeholder & 0x000F0FFF) == 0); + Value = (Value >> 16) & 0xFFFF; - *TargetPtr |= Value & 0xFFF; + *TargetPtr = *Placeholder | (Value & 0xFFF); *TargetPtr |= ((Value >> 12) & 0xF) << 16; break; - // Write 24 bit relative value to the branch instruction. case ELF::R_ARM_PC24 : // Fall through. case ELF::R_ARM_CALL : // Fall through. - case ELF::R_ARM_JUMP24 : + case ELF::R_ARM_JUMP24: { int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); RelValue = (RelValue & 0x03FFFFFC) >> 2; + assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE); *TargetPtr &= 0xFF000000; *TargetPtr |= RelValue; break; } + case ELF::R_ARM_PRIVATE_0: + // This relocation is reserved by the ARM ELF ABI for internal use. We + // appropriate it here to act as an R_ARM_ABS32 without any addend for use + // in the stubs created during JIT (which can't put an addend into the + // original object file). + *TargetPtr = Value; + break; + } } void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section, @@ -425,6 +500,8 @@ void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section, uint32_t Value, uint32_t Type, int32_t Addend) { + uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress + + Offset); uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset); Value += Addend; @@ -442,19 +519,30 @@ void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section, llvm_unreachable("Not implemented relocation type!"); break; case ELF::R_MIPS_32: - *TargetPtr = Value + (*TargetPtr); + *TargetPtr = Value + (*Placeholder); break; case ELF::R_MIPS_26: - *TargetPtr = ((*TargetPtr) & 0xfc000000) | (( Value & 0x0fffffff) >> 2); + *TargetPtr = ((*Placeholder) & 0xfc000000) | (( Value & 0x0fffffff) >> 2); break; case ELF::R_MIPS_HI16: // Get the higher 16-bits. Also add 1 if bit 15 is 1. - Value += ((*TargetPtr) & 0x0000ffff) << 16; + Value += ((*Placeholder) & 0x0000ffff) << 16; + *TargetPtr = ((*Placeholder) & 0xffff0000) | + (((Value + 0x8000) >> 16) & 0xffff); + break; + case ELF::R_MIPS_LO16: + Value += ((*Placeholder) & 0x0000ffff); + *TargetPtr = ((*Placeholder) & 0xffff0000) | (Value & 0xffff); + break; + case ELF::R_MIPS_UNUSED1: + // Similar to ELF::R_ARM_PRIVATE_0, R_MIPS_UNUSED1 and R_MIPS_UNUSED2 + // are used for internal JIT purpose. These relocations are similar to + // R_MIPS_HI16 and R_MIPS_LO16, but they do not take any addend into + // account. *TargetPtr = ((*TargetPtr) & 0xffff0000) | (((Value + 0x8000) >> 16) & 0xffff); break; - case ELF::R_MIPS_LO16: - Value += ((*TargetPtr) & 0x0000ffff); + case ELF::R_MIPS_UNUSED2: *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff); break; } @@ -499,9 +587,13 @@ void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj, error_code err; for (section_iterator si = Obj.begin_sections(), se = Obj.end_sections(); si != se; si.increment(err)) { - StringRef SectionName; - check(si->getName(SectionName)); - if (SectionName != ".opd") + section_iterator RelSecI = si->getRelocatedSection(); + if (RelSecI == Obj.end_sections()) + continue; + + StringRef RelSectionName; + check(RelSecI->getName(RelSectionName)); + if (RelSectionName != ".opd") continue; for (relocation_iterator i = si->begin_relocations(), @@ -517,12 +609,11 @@ void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj, continue; } - SymbolRef TargetSymbol; uint64_t TargetSymbolOffset; - int64_t TargetAdditionalInfo; - check(i->getSymbol(TargetSymbol)); + symbol_iterator TargetSymbol = i->getSymbol(); check(i->getOffset(TargetSymbolOffset)); - check(i->getAdditionalInfo(TargetAdditionalInfo)); + int64_t Addend; + check(getELFRelocationAddend(*i, Addend)); i = i.increment(err); if (i == e) @@ -538,13 +629,13 @@ void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj, // Finally compares the Symbol value and the target symbol offset // to check if this .opd entry refers to the symbol the relocation // points to. - if (Rel.Addend != (intptr_t)TargetSymbolOffset) + if (Rel.Addend != (int64_t)TargetSymbolOffset) continue; section_iterator tsi(Obj.end_sections()); - check(TargetSymbol.getSection(tsi)); + check(TargetSymbol->getSection(tsi)); Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections); - Rel.Addend = (intptr_t)TargetAdditionalInfo; + Rel.Addend = (intptr_t)Addend; return; } } @@ -688,20 +779,42 @@ void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, } } +// The target location for the relocation is described by RE.SectionID and +// RE.Offset. RE.SectionID can be used to find the SectionEntry. Each +// SectionEntry has three members describing its location. +// SectionEntry::Address is the address at which the section has been loaded +// into memory in the current (host) process. SectionEntry::LoadAddress is the +// address that the section will have in the target process. +// SectionEntry::ObjAddress is the address of the bits for this section in the +// original emitted object image (also in the current address space). +// +// Relocations will be applied as if the section were loaded at +// SectionEntry::LoadAddress, but they will be applied at an address based +// on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to +// Target memory contents if they are required for value calculations. +// +// The Value parameter here is the load address of the symbol for the +// relocation to be applied. For relocations which refer to symbols in the +// current object Value will be the LoadAddress of the section in which +// the symbol resides (RE.Addend provides additional information about the +// symbol location). For external symbols, Value will be the address of the +// symbol in the target address space. void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, - uint64_t Value) { + uint64_t Value) { const SectionEntry &Section = Sections[RE.SectionID]; - return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend); + return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, + RE.SymOffset); } void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, uint64_t Offset, uint64_t Value, uint32_t Type, - int64_t Addend) { + int64_t Addend, + uint64_t SymOffset) { switch (Arch) { case Triple::x86_64: - resolveX86_64Relocation(Section, Offset, Value, Type, Addend); + resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); break; case Triple::x86: resolveX86Relocation(Section, Offset, @@ -723,7 +836,8 @@ void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, (uint32_t)(Value & 0xffffffffL), Type, (uint32_t)(Addend & 0xffffffffL)); break; - case Triple::ppc64: + case Triple::ppc64: // Fall through. + case Triple::ppc64le: resolvePPC64Relocation(Section, Offset, Value, Type, Addend); break; case Triple::systemz: @@ -742,31 +856,37 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, uint64_t RelType; Check(RelI.getType(RelType)); int64_t Addend; - Check(RelI.getAdditionalInfo(Addend)); - SymbolRef Symbol; - Check(RelI.getSymbol(Symbol)); + Check(getELFRelocationAddend(RelI, Addend)); + symbol_iterator Symbol = RelI.getSymbol(); // Obtain the symbol name which is referenced in the relocation StringRef TargetName; - Symbol.getName(TargetName); + if (Symbol != Obj.end_symbols()) + Symbol->getName(TargetName); DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend << " TargetName: " << TargetName << "\n"); RelocationValueRef Value; // First search for the symbol in the local symbol table - SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data()); - SymbolRef::Type SymType; - Symbol.getType(SymType); + SymbolTableMap::const_iterator lsi = Symbols.end(); + SymbolRef::Type SymType = SymbolRef::ST_Unknown; + if (Symbol != Obj.end_symbols()) { + lsi = Symbols.find(TargetName.data()); + Symbol->getType(SymType); + } if (lsi != Symbols.end()) { Value.SectionID = lsi->second.first; + Value.Offset = lsi->second.second; Value.Addend = lsi->second.second + Addend; } else { // Search for the symbol in the global symbol table - SymbolTableMap::const_iterator gsi = - GlobalSymbolTable.find(TargetName.data()); + SymbolTableMap::const_iterator gsi = GlobalSymbolTable.end(); + if (Symbol != Obj.end_symbols()) + gsi = GlobalSymbolTable.find(TargetName.data()); if (gsi != GlobalSymbolTable.end()) { Value.SectionID = gsi->second.first; + Value.Offset = gsi->second.second; Value.Addend = gsi->second.second + Addend; } else { switch (SymType) { @@ -775,7 +895,7 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, // and can be changed by another developers. Maybe best way is add // a new symbol type ST_Section to SymbolRef and use it. section_iterator si(Obj.end_sections()); - Symbol.getSection(si); + Symbol->getSection(si); if (si == Obj.end_sections()) llvm_unreachable("Symbol section not found, bad object file format!"); DEBUG(dbgs() << "\t\tThis is section symbol\n"); @@ -789,9 +909,17 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, Value.Addend = Addend; break; } + case SymbolRef::ST_Data: case SymbolRef::ST_Unknown: { Value.SymbolName = TargetName.data(); Value.Addend = Addend; + + // Absolute relocations will have a zero symbol ID (STN_UNDEF), which + // will manifest here as a NULL symbol name. + // We can set this as a valid (but empty) symbol name, and rely + // on addRelocationForSymbol to handle this. + if (!Value.SymbolName) + Value.SymbolName = ""; break; } default: @@ -876,7 +1004,7 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, uint8_t *StubTargetAddr = createStubFunction(Section.Address + Section.StubOffset); RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, - ELF::R_ARM_ABS32, Value.Addend); + ELF::R_ARM_PRIVATE_0, Value.Addend); if (Value.SymbolName) addRelocationForSymbol(RE, Value.SymbolName); else @@ -903,8 +1031,8 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, // Look up for existing stub. StubMap::const_iterator i = Stubs.find(Value); if (i != Stubs.end()) { - resolveRelocation(Section, Offset, - (uint64_t)Section.Address + i->second, RelType, 0); + RelocationEntry RE(SectionID, Offset, RelType, i->second); + addRelocationForSection(RE, SectionID); DEBUG(dbgs() << " Stub function found\n"); } else { // Create a new stub function. @@ -916,10 +1044,10 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, // Creating Hi and Lo relocations for the filled stub instructions. RelocationEntry REHi(SectionID, StubTargetAddr - Section.Address, - ELF::R_MIPS_HI16, Value.Addend); + ELF::R_MIPS_UNUSED1, Value.Addend); RelocationEntry RELo(SectionID, StubTargetAddr - Section.Address + 4, - ELF::R_MIPS_LO16, Value.Addend); + ELF::R_MIPS_UNUSED2, Value.Addend); if (Value.SymbolName) { addRelocationForSymbol(REHi, Value.SymbolName); @@ -929,12 +1057,11 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, addRelocationForSection(RELo, Value.SectionID); } - resolveRelocation(Section, Offset, - (uint64_t)Section.Address + Section.StubOffset, - RelType, 0); + RelocationEntry RE(SectionID, Offset, RelType, Section.StubOffset); + addRelocationForSection(RE, SectionID); Section.StubOffset += getMaxStubSize(); } - } else if (Arch == Triple::ppc64) { + } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { if (RelType == ELF::R_PPC64_REL24) { // A PPC branch relocation will need a stub function if the target is // an external symbol (Symbol::ST_Unknown) or if the target address @@ -1017,7 +1144,10 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); // Extra check to avoid relocation againt empty symbols (usually // the R_PPC64_TOC). - if (Value.SymbolName && !TargetName.empty()) + if (SymType != SymbolRef::ST_Unknown && TargetName.empty()) + Value.SymbolName = NULL; + + if (Value.SymbolName) addRelocationForSymbol(RE, Value.SymbolName); else addRelocationForSection(RE, Value.SectionID); @@ -1069,8 +1199,67 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, ELF::R_390_PC32DBL, Addend); else resolveRelocation(Section, Offset, StubAddress, RelType, Addend); + } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_PLT32) { + // The way the PLT relocations normally work is that the linker allocates the + // PLT and this relocation makes a PC-relative call into the PLT. The PLT + // entry will then jump to an address provided by the GOT. On first call, the + // GOT address will point back into PLT code that resolves the symbol. After + // the first call, the GOT entry points to the actual function. + // + // For local functions we're ignoring all of that here and just replacing + // the PLT32 relocation type with PC32, which will translate the relocation + // into a PC-relative call directly to the function. For external symbols we + // can't be sure the function will be within 2^32 bytes of the call site, so + // we need to create a stub, which calls into the GOT. This case is + // equivalent to the usual PLT implementation except that we use the stub + // mechanism in RuntimeDyld (which puts stubs at the end of the section) + // rather than allocating a PLT section. + if (Value.SymbolName) { + // This is a call to an external function. + // Look for an existing stub. + SectionEntry &Section = Sections[SectionID]; + StubMap::const_iterator i = Stubs.find(Value); + uintptr_t StubAddress; + if (i != Stubs.end()) { + StubAddress = uintptr_t(Section.Address) + i->second; + DEBUG(dbgs() << " Stub function found\n"); + } else { + // Create a new stub function (equivalent to a PLT entry). + DEBUG(dbgs() << " Create a new stub function\n"); + + uintptr_t BaseAddress = uintptr_t(Section.Address); + uintptr_t StubAlignment = getStubAlignment(); + StubAddress = (BaseAddress + Section.StubOffset + + StubAlignment - 1) & -StubAlignment; + unsigned StubOffset = StubAddress - BaseAddress; + Stubs[Value] = StubOffset; + createStubFunction((uint8_t *)StubAddress); + + // Create a GOT entry for the external function. + GOTEntries.push_back(Value); + + // Make our stub function a relative call to the GOT entry. + RelocationEntry RE(SectionID, StubOffset + 2, + ELF::R_X86_64_GOTPCREL, -4); + addRelocationForSymbol(RE, Value.SymbolName); + + // Bump our stub offset counter + Section.StubOffset = StubOffset + getMaxStubSize(); + } + + // Make the target call a call into the stub table. + resolveRelocation(Section, Offset, StubAddress, + ELF::R_X86_64_PC32, Addend); + } else { + RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, + Value.Offset); + addRelocationForSection(RE, Value.SectionID); + } } else { - RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); + if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) { + GOTEntries.push_back(Value); + } + RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); if (Value.SymbolName) addRelocationForSymbol(RE, Value.SymbolName); else @@ -1078,6 +1267,137 @@ void RuntimeDyldELF::processRelocationRef(unsigned SectionID, } } +void RuntimeDyldELF::updateGOTEntries(StringRef Name, uint64_t Addr) { + + SmallVectorImpl<std::pair<SID, GOTRelocations> >::iterator it; + SmallVectorImpl<std::pair<SID, GOTRelocations> >::iterator end = GOTs.end(); + + for (it = GOTs.begin(); it != end; ++it) { + GOTRelocations &GOTEntries = it->second; + for (int i = 0, e = GOTEntries.size(); i != e; ++i) { + if (GOTEntries[i].SymbolName != 0 && GOTEntries[i].SymbolName == Name) { + GOTEntries[i].Offset = Addr; + } + } + } +} + +size_t RuntimeDyldELF::getGOTEntrySize() { + // We don't use the GOT in all of these cases, but it's essentially free + // to put them all here. + size_t Result = 0; + switch (Arch) { + case Triple::x86_64: + case Triple::aarch64: + case Triple::ppc64: + case Triple::ppc64le: + case Triple::systemz: + Result = sizeof(uint64_t); + break; + case Triple::x86: + case Triple::arm: + case Triple::thumb: + case Triple::mips: + case Triple::mipsel: + Result = sizeof(uint32_t); + break; + default: llvm_unreachable("Unsupported CPU type!"); + } + return Result; +} + +uint64_t RuntimeDyldELF::findGOTEntry(uint64_t LoadAddress, + uint64_t Offset) { + + const size_t GOTEntrySize = getGOTEntrySize(); + + SmallVectorImpl<std::pair<SID, GOTRelocations> >::const_iterator it; + SmallVectorImpl<std::pair<SID, GOTRelocations> >::const_iterator end = GOTs.end(); + + int GOTIndex = -1; + for (it = GOTs.begin(); it != end; ++it) { + SID GOTSectionID = it->first; + const GOTRelocations &GOTEntries = it->second; + + // Find the matching entry in our vector. + uint64_t SymbolOffset = 0; + for (int i = 0, e = GOTEntries.size(); i != e; ++i) { + if (GOTEntries[i].SymbolName == 0) { + if (getSectionLoadAddress(GOTEntries[i].SectionID) == LoadAddress && + GOTEntries[i].Offset == Offset) { + GOTIndex = i; + SymbolOffset = GOTEntries[i].Offset; + break; + } + } else { + // GOT entries for external symbols use the addend as the address when + // the external symbol has been resolved. + if (GOTEntries[i].Offset == LoadAddress) { + GOTIndex = i; + // Don't use the Addend here. The relocation handler will use it. + break; + } + } + } + + if (GOTIndex != -1) { + if (GOTEntrySize == sizeof(uint64_t)) { + uint64_t *LocalGOTAddr = (uint64_t*)getSectionAddress(GOTSectionID); + // Fill in this entry with the address of the symbol being referenced. + LocalGOTAddr[GOTIndex] = LoadAddress + SymbolOffset; + } else { + uint32_t *LocalGOTAddr = (uint32_t*)getSectionAddress(GOTSectionID); + // Fill in this entry with the address of the symbol being referenced. + LocalGOTAddr[GOTIndex] = (uint32_t)(LoadAddress + SymbolOffset); + } + + // Calculate the load address of this entry + return getSectionLoadAddress(GOTSectionID) + (GOTIndex * GOTEntrySize); + } + } + + assert(GOTIndex != -1 && "Unable to find requested GOT entry."); + return 0; +} + +void RuntimeDyldELF::finalizeLoad(ObjSectionToIDMap &SectionMap) { + // If necessary, allocate the global offset table + if (MemMgr) { + // Allocate the GOT if necessary + size_t numGOTEntries = GOTEntries.size(); + if (numGOTEntries != 0) { + // Allocate memory for the section + unsigned SectionID = Sections.size(); + size_t TotalSize = numGOTEntries * getGOTEntrySize(); + uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, getGOTEntrySize(), + SectionID, ".got", false); + if (!Addr) + report_fatal_error("Unable to allocate memory for GOT!"); + + GOTs.push_back(std::make_pair(SectionID, GOTEntries)); + Sections.push_back(SectionEntry(".got", Addr, TotalSize, 0)); + // For now, initialize all GOT entries to zero. We'll fill them in as + // needed when GOT-based relocations are applied. + memset(Addr, 0, TotalSize); + } + } + else { + report_fatal_error("Unable to allocate memory for GOT!"); + } + + // Look for and record the EH frame section. + ObjSectionToIDMap::iterator i, e; + for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { + const SectionRef &Section = i->first; + StringRef Name; + Section.getName(Name); + if (Name == ".eh_frame") { + UnregisteredEHFrameSections.push_back(i->second); + break; + } + } +} + bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const { if (Buffer->getBufferSize() < strlen(ELF::ElfMagic)) return false; |