diff --git a/libpolyml/elfexport.cpp b/libpolyml/elfexport.cpp index 2e69de58..8d09db61 100644 --- a/libpolyml/elfexport.cpp +++ b/libpolyml/elfexport.cpp @@ -1,852 +1,854 @@ /* Title: Write out a database as an ELF object file Author: David Matthews. Copyright (c) 2006-7, 2011, 2016-18, 2020-21 David C. J. Matthews This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License version 2.1 as published by the Free Software Foundation. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR H PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include "config.h" #ifdef HAVE_STDLIB_H #include #endif #ifdef HAVE_STDIO_H #include #endif #ifdef HAVE_STDDEF_H #include #endif #ifdef HAVE_UNISTD_H #include #endif #ifdef HAVE_ERRNO_H #include #endif #ifdef HAVE_TIME_H #include #endif #ifdef HAVE_ASSERT_H #include #define ASSERT(x) assert(x) #else #define ASSERT(x) #endif #ifdef HAVE_ELF_H #include #elif defined(HAVE_ELF_ABI_H) #include #endif #ifdef HAVE_MACHINE_RELOC_H #include #ifndef EM_X86_64 #define EM_X86_64 EM_AMD64 #endif #if defined(HOSTARCHITECTURE_X86_64) #ifndef R_386_PC32 #define R_386_PC32 R_X86_64_PC32 #endif #ifndef R_386_32 #define R_386_32 R_X86_64_32 #endif #ifndef R_X86_64_64 #define R_X86_64_64 R_X86_64_64 #endif #endif /* HOSTARCHITECTURE_X86_64 */ #endif // Solaris seems to put processor-specific constants in separate files #ifdef HAVE_SYS_ELF_SPARC_H #include #endif #ifdef HAVE_SYS_ELF_386_H #include #endif #ifdef HAVE_SYS_ELF_AMD64_H #include #endif // Android has the ARM relocation symbol here #ifdef HAVE_ASM_ELF_H #include #endif #ifdef HAVE_STRING_H #include #endif #ifdef HAVE_SYS_UTSNAME_H #include #endif #include "globals.h" #include "diagnostics.h" #include "sys.h" #include "machine_dep.h" #include "gc.h" #include "mpoly.h" #include "scanaddrs.h" #include "elfexport.h" #include "run_time.h" #include "version.h" #include "polystring.h" #include "timing.h" #include "memmgr.h" #define sym_last_local_sym sym_data_section #if defined(HOSTARCHITECTURE_X86) # define HOST_E_MACHINE EM_386 # define HOST_DIRECT_DATA_RELOC R_386_32 # define HOST_DIRECT_FPTR_RELOC R_386_32 # define USE_RELA 0 #elif defined(HOSTARCHITECTURE_PPC) # define HOST_E_MACHINE EM_PPC # define HOST_DIRECT_DATA_RELOC R_PPC_ADDR32 # define HOST_DIRECT_FPTR_RELOC R_PPC_ADDR32 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_PPC64) # define HOST_E_MACHINE EM_PPC64 # define HOST_DIRECT_DATA_RELOC R_PPC64_ADDR64 # define HOST_DIRECT_FPTR_RELOC R_PPC64_ADDR64 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_S390) # define HOST_E_MACHINE EM_S390 # define HOST_DIRECT_DATA_RELOC R_390_32 # define HOST_DIRECT_FPTR_RELOC R_390_32 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_S390X) # define HOST_E_MACHINE EM_S390 # define HOST_DIRECT_DATA_RELOC R_390_64 # define HOST_DIRECT_FPTR_RELOC R_390_64 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_SH) # define HOST_E_MACHINE EM_SH # define HOST_DIRECT_DATA_RELOC R_SH_DIR32 # define HOST_DIRECT_FPTR_RELOC R_SH_DIR32 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_SPARC) # define HOST_E_MACHINE EM_SPARC # define HOST_DIRECT_DATA_RELOC R_SPARC_32 # define HOST_DIRECT_FPTR_RELOC R_SPARC_32 # define USE_RELA 1 /* Sparc/Solaris, at least 2.8, requires ELF32_Rela relocations. For some reason, though, it adds the value in the location being relocated (as with ELF32_Rel relocations) as well as the addend. To be safe, whenever we use an ELF32_Rela relocation we always zero the location to be relocated. */ #elif defined(HOSTARCHITECTURE_SPARC64) # define HOST_E_MACHINE EM_SPARCV9 # define HOST_DIRECT_DATA_RELOC R_SPARC_64 # define HOST_DIRECT_FPTR_RELOC R_SPARC_64 /* Use the most relaxed memory model. At link time, the most restrictive one is chosen, so it does no harm to be as permissive as possible here. */ # define HOST_E_FLAGS EF_SPARCV9_RMO # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_X86_64) /* It seems Solaris/X86-64 only supports ELF64_Rela relocations. It appears that Linux will support either so we now use Rela on X86-64. */ # define HOST_E_MACHINE EM_X86_64 # define HOST_DIRECT_DATA_RELOC R_X86_64_64 # define HOST_DIRECT_FPTR_RELOC R_X86_64_64 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_X32) # define HOST_E_MACHINE EM_X86_64 # define HOST_DIRECT_DATA_RELOC R_X86_64_32 # define HOST_DIRECT_FPTR_RELOC R_X86_64_32 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_ARM) # ifndef EF_ARM_EABI_VER4 # define EF_ARM_EABI_VER4 0x04000000 # endif // When linking ARM binaries the linker checks the ABI version. We // need to set the version to the same as the libraries. // GCC currently uses version 4. # define HOST_E_MACHINE EM_ARM # define HOST_DIRECT_DATA_RELOC R_ARM_ABS32 # define HOST_DIRECT_FPTR_RELOC R_ARM_ABS32 # define USE_RELA 0 # define HOST_E_FLAGS EF_ARM_EABI_VER4 #elif defined(HOSTARCHITECTURE_HPPA) # if defined(__hpux) # define HOST_OSABI ELFOSABI_HPUX # elif defined(__NetBSD__) # define HOST_OSABI ELFOSABI_NETBSD # elif defined(__linux__) # define HOST_OSABI ELFOSABI_GNU # endif # define HOST_E_MACHINE EM_PARISC # define HOST_DIRECT_DATA_RELOC R_PARISC_DIR32 # define HOST_DIRECT_FPTR_RELOC R_PARISC_PLABEL32 # define HOST_E_FLAGS EFA_PARISC_1_0 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_IA64) # define HOST_E_MACHINE EM_IA_64 # define HOST_DIRECT_DATA_RELOC R_IA64_DIR64LSB # define HOST_DIRECT_FPTR_RELOC R_IA64_FPTR64LSB # define HOST_E_FLAGS EF_IA_64_ABI64 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_AARCH64) # define HOST_E_MACHINE EM_AARCH64 # define HOST_DIRECT_DATA_RELOC R_AARCH64_ABS64 # define HOST_DIRECT_FPTR_RELOC R_AARCH64_ABS64 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_M68K) # define HOST_E_MACHINE EM_68K # define HOST_DIRECT_DATA_RELOC R_68K_32 # define HOST_DIRECT_FPTR_RELOC R_68K_32 # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_MIPS) # define HOST_E_MACHINE EM_MIPS # define HOST_DIRECT_DATA_RELOC R_MIPS_32 # define HOST_DIRECT_FPTR_RELOC R_MIPS_32 # ifdef __PIC__ # define HOST_E_FLAGS EF_MIPS_CPIC # endif # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_MIPS64) # define HOST_E_MACHINE EM_MIPS # define HOST_DIRECT_DATA_RELOC R_MIPS_64 # define HOST_DIRECT_FPTR_RELOC R_MIPS_64 # ifdef __PIC__ # define HOST_E_FLAGS (EF_MIPS_ARCH_64 | EF_MIPS_CPIC) # else # define HOST_E_FLAGS EF_MIPS_ARCH_64 # endif # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_ALPHA) # define HOST_E_MACHINE EM_ALPHA # define HOST_DIRECT_DATA_RELOC R_ALPHA_REFQUAD # define HOST_DIRECT_FPTR_RELOC R_ALPHA_REFQUAD # define USE_RELA 1 #elif defined(HOSTARCHITECTURE_RISCV32) || defined(HOSTARCHITECTURE_RISCV64) # define HOST_E_MACHINE EM_RISCV # if defined(HOSTARCHITECTURE_RISCV32) # define HOST_DIRECT_DATA_RELOC R_RISCV_32 # define HOST_DIRECT_FPTR_RELOC R_RISCV_32 # else # define HOST_DIRECT_DATA_RELOC R_RISCV_64 # define HOST_DIRECT_FPTR_RELOC R_RISCV_64 # endif # if defined(__riscv_float_abi_soft) # define HOST_E_FLAGS_FLOAT_ABI EF_RISCV_FLOAT_ABI_SOFT # elif defined(__riscv_float_abi_single) # define HOST_E_FLAGS_FLOAT_ABI EF_RISCV_FLOAT_ABI_SINGLE # elif defined(__riscv_float_abi_double) # define HOST_E_FLAGS_FLOAT_ABI EF_RISCV_FLOAT_ABI_DOUBLE # elif defined(__riscv_float_abi_quad) # define HOST_E_FLAGS_FLOAT_ABI EF_RISCV_FLOAT_ABI_QUAD # else # error "Unknown RISC-V float ABI" # endif # ifdef __riscv_32e # define HOST_E_FLAGS_RVE __riscv_32e # else # define HOST_E_FLAGS_RVE 0 # endif # define HOST_E_FLAGS (HOST_E_FLAGS_FLOAT_ABI | HOST_E_FLAGS_RVE) # define USE_RELA 1 #else # error "No support for exporting on this architecture" #endif // The first two symbols are special: // Zero is always special in ELF // 1 is used for the data section #define EXTRA_SYMBOLS 2 static unsigned AreaToSym(unsigned area) { return area+EXTRA_SYMBOLS; } // Section table entries enum { sect_initial = 0, sect_sectionnametable, sect_stringtable, // Data and relocation entries come in here. sect_data // Finally the symbol table }; // Add an external reference to the RTS void ELFExport::addExternalReference(void *relocAddr, const char *name, bool isFuncPtr) { externTable.makeEntry(name); // The symbol is added after the memory table entries and poly_exports writeRelocation(0, relocAddr, symbolNum++, isFuncPtr); } // Generate the address relative to the start of the segment. void ELFExport::setRelocationAddress(void *p, ElfXX_Addr *reloc) { unsigned area = findArea(p); POLYUNSIGNED offset = (char*)p - (char*)memTable[area].mtOriginalAddr; *reloc = offset; } /* Get the index corresponding to an address. */ PolyWord ELFExport::createRelocation(PolyWord p, void *relocAddr) { void *addr = p.AsAddress(); unsigned addrArea = findArea(addr); POLYUNSIGNED offset = (char*)addr - (char*)memTable[addrArea].mtOriginalAddr; return writeRelocation(offset, relocAddr, AreaToSym(addrArea), false); } PolyWord ELFExport::writeRelocation(POLYUNSIGNED offset, void *relocAddr, unsigned symbolNum, bool isFuncPtr) { #if USE_RELA ElfXX_Rela reloc; reloc.r_addend = offset; offset = 0; #else ElfXX_Rel reloc; #endif // Set the offset within the section we're scanning. setRelocationAddress(relocAddr, &reloc.r_offset); #ifdef HOSTARCHITECTURE_MIPS64 reloc.r_sym = symbolNum; reloc.r_ssym = 0; reloc.r_type = isFuncPtr ? HOST_DIRECT_FPTR_RELOC : HOST_DIRECT_DATA_RELOC; reloc.r_type2 = 0; reloc.r_type3 = 0; #else reloc.r_info = ELFXX_R_INFO(symbolNum, isFuncPtr ? HOST_DIRECT_FPTR_RELOC : HOST_DIRECT_DATA_RELOC); #endif fwrite(&reloc, sizeof(reloc), 1, exportFile); relocationCount++; return PolyWord::FromUnsigned(offset); } /* This is called for each constant within the code. Print a relocation entry for the word and return a value that means that the offset is saved in original word. */ void ELFExport::ScanConstant(PolyObject *base, byte *addr, ScanRelocationKind code, intptr_t displacement) { #ifndef POLYML32IN64 PolyObject *p = GetConstantValue(addr, code, displacement); if (p == 0) return; void *a = p; unsigned aArea = findArea(a); // We don't need a relocation if this is relative to the current segment // since the relative address will already be right. if (code == PROCESS_RELOC_I386RELATIVE && aArea == findArea(addr)) return; // Set the value at the address to the offset relative to the symbol. POLYUNSIGNED offset = (char*)a - (char*)memTable[aArea].mtOriginalAddr; switch (code) { case PROCESS_RELOC_DIRECT: // 32 or 64 bit address of target { PolyWord r = createRelocation(p, addr); POLYUNSIGNED w = r.AsUnsigned(); for (unsigned i = 0; i < sizeof(PolyWord); i++) { addr[i] = (byte)(w & 0xff); w >>= 8; } } break; #if(defined(HOSTARCHITECTURE_X86) || defined(HOSTARCHITECTURE_X86_64) || \ defined(HOSTARCHITECTURE_X32)) #ifdef HOSTARCHITECTURE_X86 #define R_PC_RELATIVE R_386_PC32 #else #define R_PC_RELATIVE R_X86_64_PC32 #endif case PROCESS_RELOC_I386RELATIVE: // 32 bit relative address { // We seem to need to subtract 4 bytes to get the correct offset in ELF offset -= 4; #if USE_RELA ElfXX_Rela reloc; reloc.r_addend = offset; #else ElfXX_Rel reloc; #endif setRelocationAddress(addr, &reloc.r_offset); reloc.r_info = ELFXX_R_INFO(AreaToSym(aArea), R_PC_RELATIVE); byte *writAble = gMem.SpaceForAddress(addr)->writeAble(addr); #if USE_RELA // Clear the field. Even though it's not supposed to be used with Rela the // Linux linker at least seems to add the value in here sometimes. memset(writAble, 0, 4); #else for (unsigned i = 0; i < 4; i++) { writAble[i] = (byte)(offset & 0xff); offset >>= 8; } #endif fwrite(&reloc, sizeof(reloc), 1, exportFile); relocationCount++; } break; #endif +#if defined(HOSTARCHITECTURE_AARCH64) case PROCESS_RELOC_ARM64ADRPLDR: // ADRP/LDR pair { ElfXX_Rela reloc; reloc.r_addend = offset; setRelocationAddress(addr, &reloc.r_offset); reloc.r_info = ELFXX_R_INFO(AreaToSym(aArea), R_AARCH64_ADR_PREL_PG_HI21); fwrite(&reloc, sizeof(reloc), 1, exportFile); relocationCount++; setRelocationAddress(addr+4, &reloc.r_offset); reloc.r_info = ELFXX_R_INFO(AreaToSym(aArea), R_AARCH64_LDST64_ABS_LO12_NC); fwrite(&reloc, sizeof(reloc), 1, exportFile); relocationCount++; // Clear the offsets within the instruction just in case uint32_t* writAble = (uint32_t *)gMem.SpaceForAddress(addr)->writeAble(addr); writAble[0] = (writAble[0] & 0x9f00001f); writAble[1] = (writAble[1] & 0xffc003ff); } break; +#endif default: ASSERT(0); // Wrong type of relocation for this architecture. } #endif } unsigned long ELFExport::makeStringTableEntry(const char *str, ExportStringTable *stab) { if (str == NULL || str[0] == 0) return 0; // First entry is the null string. else return stab->makeEntry(str); } void ELFExport::writeSymbol(const char *symbolName, long value, long size, int binding, int sttype, int section) { ElfXX_Sym symbol; memset(&symbol, 0, sizeof(symbol)); // Zero unused fields symbol.st_name = makeStringTableEntry(symbolName, &symStrings); symbol.st_value = value; symbol.st_size = size; symbol.st_info = ELFXX_ST_INFO(binding, sttype); symbol.st_other = 0; symbol.st_shndx = section; fwrite(&symbol, sizeof(symbol), 1, exportFile); } // Set the file alignment. void ELFExport::alignFile(int align) { char pad[32] = {0}; // Maximum alignment int offset = ftell(exportFile); if ((offset % align) == 0) return; fwrite(&pad, align - (offset % align), 1, exportFile); } void ELFExport::createStructsRelocation(unsigned sym, size_t offset, size_t addend) { #if USE_RELA ElfXX_Rela reloc; reloc.r_addend = addend; #else ElfXX_Rel reloc; #endif reloc.r_offset = offset; #ifdef HOSTARCHITECTURE_MIPS64 reloc.r_sym = sym; reloc.r_ssym = 0; reloc.r_type = HOST_DIRECT_DATA_RELOC; reloc.r_type2 = 0; reloc.r_type3 = 0; #else reloc.r_info = ELFXX_R_INFO(sym, HOST_DIRECT_DATA_RELOC); #endif fwrite(&reloc, sizeof(reloc), 1, exportFile); relocationCount++; } void ELFExport::exportStore(void) { PolyWord *p; ElfXX_Ehdr fhdr; ElfXX_Shdr *sections = 0; #ifdef __linux__ unsigned extraSections = 1; // Extra section for .note.GNU-stack #else unsigned extraSections = 0; #endif unsigned numSections = 0; for (unsigned j = 0; j < memTableEntries; j++) { if ((memTable[j].mtFlags & (MTF_BYTES|MTF_WRITEABLE)) == MTF_BYTES) numSections += 1; else numSections += 2; } // The symbol table comes at the end. unsigned sect_symtab = sect_data + numSections + 2; numSections += 6 + extraSections; // External symbols start after the memory table entries and "poly_exports". symbolNum = EXTRA_SYMBOLS+memTableEntries+1; // Both the string tables have an initial null entry. symStrings.makeEntry(""); sectionStrings.makeEntry(""); // Write out initial values for the headers. These are overwritten at the end. // File header memset(&fhdr, 0, sizeof(fhdr)); fhdr.e_ident[EI_MAG0] = 0x7f; fhdr.e_ident[EI_MAG1] = 'E'; fhdr.e_ident[EI_MAG2] = 'L'; fhdr.e_ident[EI_MAG3] = 'F'; fhdr.e_ident[EI_CLASS] = ELFCLASSXX; // ELFCLASS32 or ELFCLASS64 fhdr.e_ident[EI_VERSION] = EV_CURRENT; #ifdef HOST_OSABI fhdr.e_ident[EI_OSABI] = HOST_OSABI; #endif { union { unsigned long wrd; char chrs[sizeof(unsigned long)]; } endian; endian.wrd = 1; if (endian.chrs[0] == 0) fhdr.e_ident[EI_DATA] = ELFDATA2MSB; // Big endian else fhdr.e_ident[EI_DATA] = ELFDATA2LSB; // Little endian } fhdr.e_type = ET_REL; // The machine needs to match the machine we're compiling for // even if this is actually portable code. fhdr.e_machine = HOST_E_MACHINE; #ifdef HOST_E_FLAGS fhdr.e_flags = HOST_E_FLAGS; #endif fhdr.e_version = EV_CURRENT; fhdr.e_shoff = sizeof(fhdr); // Offset to section header - immediately follows fhdr.e_ehsize = sizeof(fhdr); fhdr.e_shentsize = sizeof(ElfXX_Shdr); fhdr.e_shnum = numSections; fhdr.e_shstrndx = sect_sectionnametable; // Section name table section index; fwrite(&fhdr, sizeof(fhdr), 1, exportFile); // Write it for the moment. sections = new ElfXX_Shdr[numSections]; memset(sections, 0, sizeof(ElfXX_Shdr) * numSections); // Necessary? // Set up the section header but don't write it yet. // Section 0 - all zeros sections[sect_initial].sh_type = SHT_NULL; sections[sect_initial].sh_link = SHN_UNDEF; // Section name table. sections[sect_sectionnametable].sh_name = makeStringTableEntry(".shstrtab", §ionStrings); sections[sect_sectionnametable].sh_type = SHT_STRTAB; sections[sect_sectionnametable].sh_addralign = sizeof(char); // sections[sect_sectionnametable].sh_offset is set later // sections[sect_sectionnametable].sh_size is set later // Symbol name table. sections[sect_stringtable].sh_name = makeStringTableEntry(".strtab", §ionStrings); sections[sect_stringtable].sh_type = SHT_STRTAB; sections[sect_stringtable].sh_addralign = sizeof(char); // sections[sect_stringtable].sh_offset is set later // sections[sect_stringtable].sh_size is set later unsigned long dataName = makeStringTableEntry(".data", §ionStrings); unsigned long dataRelName = makeStringTableEntry(USE_RELA ? ".rela.data" : ".rel.data", §ionStrings); #ifndef CODEISNOTEXECUTABLE unsigned long textName = makeStringTableEntry(".text", §ionStrings); unsigned long textRelName = makeStringTableEntry(USE_RELA ? ".rela.text" : ".rel.text", §ionStrings); #endif // The Linux linker does not like relocations in the .rodata section and marks the executable // as containing text relocations. Putting the data in a .data.rel.ro section seems to work. unsigned long relDataName = makeStringTableEntry(".data.rel.ro", §ionStrings); unsigned long relDataRelName = makeStringTableEntry(USE_RELA ? ".rela.data.rel.ro" : ".rel.data.rel.ro", §ionStrings); // Byte and other leaf data that do not require relocation can go in the .rodata section unsigned long nRelDataName = makeStringTableEntry(".rodata", §ionStrings); // Main data sections. Each one has a relocation section. unsigned s = sect_data; for (unsigned i=0; i < memTableEntries; i++) { sections[s].sh_addralign = 8; // 8-byte alignment sections[s].sh_type = SHT_PROGBITS; if (memTable[i].mtFlags & MTF_WRITEABLE) { // Mutable areas ASSERT(!(memTable[i].mtFlags & MTF_EXECUTABLE)); // Executable areas can't be writable. sections[s].sh_name = dataName; sections[s].sh_flags = SHF_WRITE | SHF_ALLOC; s++; // Mutable byte areas can contain external references so need relocation sections[s].sh_name = dataRelName; // Name of relocation section } #ifndef CODEISNOTEXECUTABLE // Not if we're building the interpreted version. else if (memTable[i].mtFlags & MTF_EXECUTABLE) { // Code areas are marked as executable. sections[s].sh_name = textName; sections[s].sh_flags = SHF_ALLOC | SHF_EXECINSTR; s++; sections[s].sh_name = textRelName; // Name of relocation section } #endif else if (memTable[i].mtFlags & MTF_BYTES) { // Data that does not require relocation. // Non-code immutable areas sections[s].sh_name = nRelDataName; sections[s].sh_flags = SHF_ALLOC; s++; continue; // Skip the relocation section for this } else { // Non-code immutable areas sections[s].sh_name = relDataName; // The .data.rel.ro has to be writable in order to be relocated. // It is set to read-only after relocation. sections[s].sh_flags = SHF_WRITE | SHF_ALLOC; s++; sections[s].sh_name = relDataRelName; // Name of relocation section } // sections[s].sh_size is set later // sections[s].sh_offset is set later. // sections[s].sh_size is set later. // Relocation section sections[s].sh_type = USE_RELA ? SHT_RELA : SHT_REL; // Contains relocation with/out explicit addends (ElfXX_Rel) sections[s].sh_link = sect_symtab; // Index to symbol table sections[s].sh_info = s-1; // Applies to the data section sections[s].sh_addralign = sizeof(long); // Align to a word sections[s].sh_entsize = USE_RELA ? sizeof(ElfXX_Rela) : sizeof(ElfXX_Rel); s++; // sections[s+1].sh_offset is set later. // sections[s+1].sh_size is set later. } // Table data - Poly tables that describe the memory layout. unsigned sect_table_data = s; sections[sect_table_data].sh_name = dataName; sections[sect_table_data].sh_type = SHT_PROGBITS; sections[sect_table_data].sh_flags = SHF_WRITE | SHF_ALLOC; sections[sect_table_data].sh_addralign = 8; // 8-byte alignment // Table relocation sections[sect_table_data+1].sh_name = dataRelName; sections[sect_table_data+1].sh_type = USE_RELA ? SHT_RELA : SHT_REL; // Contains relocation with/out explicit addends (ElfXX_Rel) sections[sect_table_data+1].sh_link = sect_symtab; // Index to symbol table sections[sect_table_data+1].sh_info = sect_table_data; // Applies to table section sections[sect_table_data+1].sh_addralign = sizeof(long); // Align to a word sections[sect_table_data+1].sh_entsize = USE_RELA ? sizeof(ElfXX_Rela) : sizeof(ElfXX_Rel); // Symbol table. sections[sect_symtab].sh_name = makeStringTableEntry(".symtab", §ionStrings); sections[sect_symtab].sh_type = SHT_SYMTAB; sections[sect_symtab].sh_link = sect_stringtable; // String table to use sections[sect_symtab].sh_addralign = sizeof(long); // Align to a word sections[sect_symtab].sh_entsize = sizeof(ElfXX_Sym); // sections[sect_symtab].sh_info is set later // sections[sect_symtab].sh_size is set later // sections[sect_symtab].sh_offset is set later #ifdef __linux__ // Add a .note.GNU-stack section to indicate this does not require executable stack sections[numSections-1].sh_name = makeStringTableEntry(".note.GNU-stack", §ionStrings); sections[numSections - 1].sh_type = SHT_PROGBITS; #endif // Write the relocations. unsigned relocSection = sect_data; for (unsigned i = 0; i < memTableEntries; i++) { relocSection++; if ((memTable[i].mtFlags & (MTF_BYTES|MTF_WRITEABLE)) == MTF_BYTES) continue; alignFile(sections[relocSection].sh_addralign); sections[relocSection].sh_offset = ftell(exportFile); relocationCount = 0; // Create the relocation table and turn all addresses into offsets. char *start = (char*)memTable[i].mtOriginalAddr; char *end = start + memTable[i].mtLength; for (p = (PolyWord*)start; p < (PolyWord*)end; ) { p++; PolyObject *obj = (PolyObject*)p; POLYUNSIGNED length = obj->Length(); if (length != 0 && obj->IsCodeObject()) { POLYUNSIGNED constCount; PolyWord* cp; // Get the constant area pointer first because ScanConstantsWithinCode // may alter it. machineDependent->GetConstSegmentForCode(obj, cp, constCount); // Update any constants before processing the object // We need that for relative jumps/calls in X86/64. machineDependent->ScanConstantsWithinCode(obj, this); if (cp > (PolyWord*)obj && cp < ((PolyWord*)obj) + length) { // Process the constants if they're in the area but not if they've been moved. for (POLYUNSIGNED i = 0; i < constCount; i++) relocateValue(&(cp[i])); } } else relocateObject(obj); p += length; } sections[relocSection].sh_size = relocationCount * (USE_RELA ? sizeof(ElfXX_Rela) : sizeof(ElfXX_Rel)); relocSection++; } // Relocations for "exports" and "memTable"; alignFile(sections[sect_table_data+1].sh_addralign); sections[sect_table_data+1].sh_offset = ftell(exportFile); relocationCount = 0; // TODO: This won't be needed if we put these in a separate section. POLYUNSIGNED areaSpace = 0; for (unsigned i = 0; i < memTableEntries; i++) areaSpace += memTable[i].mtLength; // Address of "memTable" within "exports". We can't use createRelocation because // the position of the relocation is not in either the mutable or the immutable area. size_t memTableOffset = sizeof(exportDescription); // It follows immediately after this. createStructsRelocation(AreaToSym(memTableEntries), offsetof(exportDescription, memTable), memTableOffset); // Address of "rootFunction" within "exports" unsigned rootAddrArea = findArea(rootFunction); size_t rootOffset = (char*)rootFunction - (char*)memTable[rootAddrArea].mtOriginalAddr; createStructsRelocation(AreaToSym(rootAddrArea), offsetof(exportDescription, rootFunction), rootOffset); // Addresses of the areas within memtable. for (unsigned i = 0; i < memTableEntries; i++) { createStructsRelocation(AreaToSym(i), sizeof(exportDescription) + i * sizeof(memoryTableEntry) + offsetof(memoryTableEntry, mtCurrentAddr), 0 /* No offset relative to base symbol*/); } sections[sect_table_data+1].sh_size = relocationCount * (USE_RELA ? sizeof(ElfXX_Rela) : sizeof(ElfXX_Rel)); // Now the symbol table. alignFile(sections[sect_symtab].sh_addralign); sections[sect_symtab].sh_offset = ftell(exportFile); writeSymbol("", 0, 0, 0, 0, 0); // Initial symbol // Write the local symbols first. writeSymbol("", 0, 0, STB_LOCAL, STT_SECTION, sect_data); // .data section // Create symbols for the address areas. AreaToSym assumes these come first. s = sect_data; for (unsigned i = 0; i < memTableEntries; i++) { char buff[50]; sprintf(buff, "area%1u", i); writeSymbol(buff, 0, 0, STB_LOCAL, STT_OBJECT, s); if ((memTable[i].mtFlags & (MTF_BYTES|MTF_WRITEABLE)) == MTF_BYTES) s += 1; else s += 2; } // Global symbols - Exported symbol for table. writeSymbol("poly_exports", 0, sizeof(exportDescription)+sizeof(memoryTableEntry)*memTableEntries, STB_GLOBAL, STT_OBJECT, sect_table_data); // External references for (unsigned i = 0; i < externTable.stringSize; i += (unsigned)strlen(externTable.strings+i) + 1) writeSymbol(externTable.strings+i, 0, 0, STB_GLOBAL, STT_FUNC, SHN_UNDEF); sections[sect_symtab].sh_info = EXTRA_SYMBOLS+memTableEntries; // One more than last local sym sections[sect_symtab].sh_size = sizeof(ElfXX_Sym) * symbolNum; // Now the binary data. unsigned dataSection = sect_data; for (unsigned i = 0; i < memTableEntries; i++) { sections[dataSection].sh_size = memTable[i].mtLength; alignFile(sections[dataSection].sh_addralign); sections[dataSection].sh_offset = ftell(exportFile); fwrite(memTable[i].mtOriginalAddr, 1, memTable[i].mtLength, exportFile); if ((memTable[i].mtFlags & (MTF_BYTES|MTF_WRITEABLE)) == MTF_BYTES) dataSection += 1; else dataSection += 2; } exportDescription exports; memset(&exports, 0, sizeof(exports)); exports.structLength = sizeof(exportDescription); exports.memTableSize = sizeof(memoryTableEntry); exports.memTableEntries = memTableEntries; exports.memTable = USE_RELA ? 0 : (memoryTableEntry *)memTableOffset; // Set the value to be the offset relative to the base of the area. We have set a relocation // already which will add the base of the area. exports.rootFunction = USE_RELA ? 0 : (void*)rootOffset; exports.timeStamp = getBuildTime(); exports.architecture = machineDependent->MachineArchitecture(); exports.rtsVersion = POLY_version_number; #ifdef POLYML32IN64 exports.originalBaseAddr = globalHeapBase; #else exports.originalBaseAddr = 0; #endif // Set the address values to zero before we write. They will always // be relative to their base symbol. for (unsigned i = 0; i < memTableEntries; i++) memTable[i].mtCurrentAddr = 0; // Now the binary data. alignFile(sections[sect_table_data].sh_addralign); sections[sect_table_data].sh_offset = ftell(exportFile); sections[sect_table_data].sh_size = sizeof(exportDescription) + memTableEntries*sizeof(memoryTableEntry); fwrite(&exports, sizeof(exports), 1, exportFile); fwrite(memTable, sizeof(memoryTableEntry), memTableEntries, exportFile); // The section name table sections[sect_sectionnametable].sh_offset = ftell(exportFile); fwrite(sectionStrings.strings, sectionStrings.stringSize, 1, exportFile); sections[sect_sectionnametable].sh_size = sectionStrings.stringSize; // The symbol name table sections[sect_stringtable].sh_offset = ftell(exportFile); fwrite(symStrings.strings, symStrings.stringSize, 1, exportFile); sections[sect_stringtable].sh_size = symStrings.stringSize; // Finally the section headers. alignFile(4); fhdr.e_shoff = ftell(exportFile); fwrite(sections, sizeof(ElfXX_Shdr) * numSections, 1, exportFile); // Rewind to rewrite the file header with the offset of the section headers. rewind(exportFile); fwrite(&fhdr, sizeof(fhdr), 1, exportFile); fclose(exportFile); exportFile = NULL; delete[]sections; }