diff options
| -rw-r--r-- | rts/Linker.c | 1714 | ||||
| -rw-r--r-- | rts/LinkerInternals.h | 12 | ||||
| -rw-r--r-- | rts/linker/Elf.c | 1709 | ||||
| -rw-r--r-- | rts/linker/Elf.h | 17 |
4 files changed, 1743 insertions, 1709 deletions
diff --git a/rts/Linker.c b/rts/Linker.c index 7b4753e0ea..27a8ffc098 100644 --- a/rts/Linker.c +++ b/rts/Linker.c @@ -59,6 +59,7 @@ #if defined(linux_HOST_OS) || defined(solaris2_HOST_OS) || defined(freebsd_HOST_OS) || defined(kfreebsdgnu_HOST_OS) || defined(dragonfly_HOST_OS) || defined(netbsd_HOST_OS) || defined(openbsd_HOST_OS) || defined(gnu_HOST_OS) # define OBJFORMAT_ELF +# include "linker/Elf.h" # include <regex.h> // regex is already used by dlopen() so this is OK // to use here without requiring an additional lib #elif defined (mingw32_HOST_OS) @@ -157,7 +158,7 @@ 2) The number of duplicate symbols, since now only symbols that are true duplicates will display the error. */ -static /*Str*/HashTable *symhash; +/*Str*/HashTable *symhash; /* List of currently loaded objects */ ObjectCode *objects = NULL; /* initially empty */ @@ -188,53 +189,6 @@ static ObjectCode* mkOc( pathchar *path, char *image, int imageSize, /* Generic wrapper function to try and Resolve and RunInit oc files */ int ocTryLoad( ObjectCode* oc ); -#if defined(OBJFORMAT_ELF) -static int ocVerifyImage_ELF ( ObjectCode* oc ); -static int ocGetNames_ELF ( ObjectCode* oc ); -static int ocResolve_ELF ( ObjectCode* oc ); -static int ocRunInit_ELF ( ObjectCode* oc ); -#if NEED_SYMBOL_EXTRAS -static int ocAllocateSymbolExtras_ELF ( ObjectCode* oc ); -#endif -#endif - -/* on x86_64 we have a problem with relocating symbol references in - * code that was compiled without -fPIC. By default, the small memory - * model is used, which assumes that symbol references can fit in a - * 32-bit slot. The system dynamic linker makes this work for - * references to shared libraries by either (a) allocating a jump - * table slot for code references, or (b) moving the symbol at load - * time (and copying its contents, if necessary) for data references. - * - * We unfortunately can't tell whether symbol references are to code - * or data. So for now we assume they are code (the vast majority - * are), and allocate jump-table slots. Unfortunately this will - * SILENTLY generate crashing code for data references. This hack is - * enabled by X86_64_ELF_NONPIC_HACK. - * - * One workaround is to use shared Haskell libraries. This is - * coming. Another workaround is to keep the static libraries but - * compile them with -fPIC, because that will generate PIC references - * to data which can be relocated. The PIC code is still too green to - * do this systematically, though. - * - * See bug #781 - * See thread http://www.haskell.org/pipermail/cvs-ghc/2007-September/038458.html - * - * Naming Scheme for Symbol Macros - * - * SymI_*: symbol is internal to the RTS. It resides in an object - * file/library that is statically. - * SymE_*: symbol is external to the RTS library. It might be linked - * dynamically. - * - * Sym*_HasProto : the symbol prototype is imported in an include file - * or defined explicitly - * Sym*_NeedsProto: the symbol is undefined and we add a dummy - * default proto extern void sym(void); - */ -#define X86_64_ELF_NONPIC_HACK 1 - /* Link objects into the lower 2Gb on x86_64. GHC assumes the * small memory model on this architecture (see gcc docs, * -mcmodel=small). @@ -328,7 +282,7 @@ static void ghciRemoveSymbolTable(HashTable *table, const SymbolName* key, mostly because it's unsure how the weak symbols support should look. See Trac #11223 */ -static int ghciInsertSymbolTable( +int ghciInsertSymbolTable( pathchar* obj_name, HashTable *table, const SymbolName* key, @@ -893,14 +847,14 @@ HsInt insertSymbol(pathchar* obj_name, SymbolName* key, SymbolAddr* data) * lookup a symbol in the hash table */ #if defined(OBJFORMAT_PEi386) -static SymbolAddr* lookupSymbol_ (SymbolName* lbl) +SymbolAddr* lookupSymbol_ (SymbolName* lbl) { return lookupSymbol_PEi386(lbl); } #else -static SymbolAddr* lookupSymbol_ (SymbolName* lbl) +SymbolAddr* lookupSymbol_ (SymbolName* lbl) { IF_DEBUG(linker, debugBelch("lookupSymbol: looking up %s\n", lbl)); @@ -2307,1661 +2261,3 @@ addSection (Section *s, SectionKind kind, SectionAlloc alloc, size, kind )); } -/* -------------------------------------------------------------------------- - * ELF specifics - * ------------------------------------------------------------------------*/ - -#if defined(OBJFORMAT_ELF) - -#define FALSE 0 -#define TRUE 1 - -#if defined(sparc_HOST_ARCH) -# define ELF_TARGET_SPARC /* Used inside <elf.h> */ -#elif defined(i386_HOST_ARCH) -# define ELF_TARGET_386 /* Used inside <elf.h> */ -#elif defined(x86_64_HOST_ARCH) -# define ELF_TARGET_X64_64 -# define ELF_64BIT -# define ELF_TARGET_AMD64 /* Used inside <elf.h> on Solaris 11 */ -#elif defined(powerpc64_HOST_ARCH) || defined(powerpc64le_HOST_ARCH) -# define ELF_64BIT -#elif defined(ia64_HOST_ARCH) -# define ELF_64BIT -#elif defined(aarch64_HOST_ARCH) -# define ELF_64BIT -#endif - -#if !defined(openbsd_HOST_OS) -# include <elf.h> -#else -/* openbsd elf has things in different places, with diff names */ -# include <elf_abi.h> -# include <machine/reloc.h> -# define R_386_32 RELOC_32 -# define R_386_PC32 RELOC_PC32 -#endif - -/* If elf.h doesn't define it */ -# ifndef R_X86_64_PC64 -# define R_X86_64_PC64 24 -# endif - -/* - * Workaround for libc implementations (e.g. eglibc) with incomplete - * relocation lists - */ -#ifndef R_ARM_THM_CALL -# define R_ARM_THM_CALL 10 -#endif -#ifndef R_ARM_CALL -# define R_ARM_CALL 28 -#endif -#ifndef R_ARM_JUMP24 -# define R_ARM_JUMP24 29 -#endif -#ifndef R_ARM_THM_JUMP24 -# define R_ARM_THM_JUMP24 30 -#endif -#ifndef R_ARM_TARGET1 -# define R_ARM_TARGET1 38 -#endif -#ifndef R_ARM_MOVW_ABS_NC -# define R_ARM_MOVW_ABS_NC 43 -#endif -#ifndef R_ARM_MOVT_ABS -# define R_ARM_MOVT_ABS 44 -#endif -#ifndef R_ARM_THM_MOVW_ABS_NC -# define R_ARM_THM_MOVW_ABS_NC 47 -#endif -#ifndef R_ARM_THM_MOVT_ABS -# define R_ARM_THM_MOVT_ABS 48 -#endif -#ifndef R_ARM_THM_JUMP11 -# define R_ARM_THM_JUMP11 102 -#endif -#ifndef R_ARM_THM_JUMP8 -# define R_ARM_THM_JUMP8 103 -#endif - -/* - * Define a set of types which can be used for both ELF32 and ELF64 - */ - -#ifdef ELF_64BIT -#define ELFCLASS ELFCLASS64 -#define Elf_Addr Elf64_Addr -#define Elf_Word Elf64_Word -#define Elf_Sword Elf64_Sword -#define Elf_Half Elf64_Half -#define Elf_Ehdr Elf64_Ehdr -#define Elf_Phdr Elf64_Phdr -#define Elf_Shdr Elf64_Shdr -#define Elf_Sym Elf64_Sym -#define Elf_Rel Elf64_Rel -#define Elf_Rela Elf64_Rela -#ifndef ELF_ST_TYPE -#define ELF_ST_TYPE ELF64_ST_TYPE -#endif -#ifndef ELF_ST_BIND -#define ELF_ST_BIND ELF64_ST_BIND -#endif -#ifndef ELF_R_TYPE -#define ELF_R_TYPE ELF64_R_TYPE -#endif -#ifndef ELF_R_SYM -#define ELF_R_SYM ELF64_R_SYM -#endif -#else -#define ELFCLASS ELFCLASS32 -#define Elf_Addr Elf32_Addr -#define Elf_Word Elf32_Word -#define Elf_Sword Elf32_Sword -#define Elf_Half Elf32_Half -#define Elf_Ehdr Elf32_Ehdr -#define Elf_Phdr Elf32_Phdr -#define Elf_Shdr Elf32_Shdr -#define Elf_Sym Elf32_Sym -#define Elf_Rel Elf32_Rel -#define Elf_Rela Elf32_Rela -#ifndef ELF_ST_TYPE -#define ELF_ST_TYPE ELF32_ST_TYPE -#endif -#ifndef ELF_ST_BIND -#define ELF_ST_BIND ELF32_ST_BIND -#endif -#ifndef ELF_R_TYPE -#define ELF_R_TYPE ELF32_R_TYPE -#endif -#ifndef ELF_R_SYM -#define ELF_R_SYM ELF32_R_SYM -#endif -#endif - - -/* - * Functions to allocate entries in dynamic sections. Currently we simply - * preallocate a large number, and we don't check if a entry for the given - * target already exists (a linear search is too slow). Ideally these - * entries would be associated with symbols. - */ - -/* These sizes sufficient to load HSbase + HShaskell98 + a few modules */ -#define GOT_SIZE 0x20000 -#define FUNCTION_TABLE_SIZE 0x10000 -#define PLT_SIZE 0x08000 - -#ifdef ELF_NEED_GOT -static Elf_Addr got[GOT_SIZE]; -static unsigned int gotIndex; -static Elf_Addr gp_val = (Elf_Addr)got; - -static Elf_Addr -allocateGOTEntry(Elf_Addr target) -{ - Elf_Addr *entry; - - if (gotIndex >= GOT_SIZE) - barf("Global offset table overflow"); - - entry = &got[gotIndex++]; - *entry = target; - return (Elf_Addr)entry; -} -#endif - -#ifdef ELF_FUNCTION_DESC -typedef struct { - Elf_Addr ip; - Elf_Addr gp; -} FunctionDesc; - -static FunctionDesc functionTable[FUNCTION_TABLE_SIZE]; -static unsigned int functionTableIndex; - -static Elf_Addr -allocateFunctionDesc(Elf_Addr target) -{ - FunctionDesc *entry; - - if (functionTableIndex >= FUNCTION_TABLE_SIZE) - barf("Function table overflow"); - - entry = &functionTable[functionTableIndex++]; - entry->ip = target; - entry->gp = (Elf_Addr)gp_val; - return (Elf_Addr)entry; -} - -static Elf_Addr -copyFunctionDesc(Elf_Addr target) -{ - FunctionDesc *olddesc = (FunctionDesc *)target; - FunctionDesc *newdesc; - - newdesc = (FunctionDesc *)allocateFunctionDesc(olddesc->ip); - newdesc->gp = olddesc->gp; - return (Elf_Addr)newdesc; -} -#endif - -#ifdef ELF_NEED_PLT - -typedef struct { - unsigned char code[sizeof(plt_code)]; -} PLTEntry; - -static Elf_Addr -allocatePLTEntry(Elf_Addr target, ObjectCode *oc) -{ - PLTEntry *plt = (PLTEntry *)oc->plt; - PLTEntry *entry; - - if (oc->pltIndex >= PLT_SIZE) - barf("Procedure table overflow"); - - entry = &plt[oc->pltIndex++]; - memcpy(entry->code, plt_code, sizeof(entry->code)); - PLT_RELOC(entry->code, target); - return (Elf_Addr)entry; -} - -static unsigned int -PLTSize(void) -{ - return (PLT_SIZE * sizeof(PLTEntry)); -} -#endif - -/* - - Note [Many ELF Sections] - - The normal section number fields in ELF are limited to 16 bits, which runs - out of bits when you try to cram in more sections than that. - - To solve this, the fields e_shnum and e_shstrndx in the ELF header have an - escape value (different for each case), and the actual section number is - stashed into unused fields in the first section header. - - For symbols, there seems to have been no place in the actual symbol table - for the extra bits, so the indexes have been moved into an auxilliary - section instead. - For symbols in sections beyond 0xff00, the symbol's st_shndx will be an - escape value (SHN_XINDEX), and the actual 32-bit section number for symbol N - is stored at index N in the SHT_SYMTAB_SHNDX table. - - These extensions seem to be undocumented in version 4.1 of the ABI and only - appear in the drafts for the "next" version: - https://refspecs.linuxfoundation.org/elf/gabi4+/contents.html - -*/ - -static Elf_Word elf_shnum(Elf_Ehdr* ehdr) -{ - Elf_Shdr* shdr = (Elf_Shdr*) ((char*)ehdr + ehdr->e_shoff); - Elf_Half shnum = ehdr->e_shnum; - return shnum != SHN_UNDEF ? shnum : shdr[0].sh_size; -} - -static Elf_Word elf_shstrndx(Elf_Ehdr* ehdr) -{ - Elf_Shdr* shdr = (Elf_Shdr*) ((char*)ehdr + ehdr->e_shoff); - Elf_Half shstrndx = ehdr->e_shstrndx; -#if defined(SHN_XINDEX) - return shstrndx != SHN_XINDEX ? shstrndx : shdr[0].sh_link; -#else - // some OSes do not support SHN_XINDEX yet, let's revert to - // old way - return shstrndx; -#endif -} - -#if defined(SHN_XINDEX) -static Elf_Word* -get_shndx_table(Elf_Ehdr* ehdr) -{ - Elf_Word i; - char* ehdrC = (char*)ehdr; - Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); - const Elf_Word shnum = elf_shnum(ehdr); - - for (i = 0; i < shnum; i++) { - if (shdr[i].sh_type == SHT_SYMTAB_SHNDX) { - return (Elf32_Word*)(ehdrC + shdr[i].sh_offset); - } - } - return NULL; -} -#endif - -/* - * Generic ELF functions - */ - -static int -ocVerifyImage_ELF ( ObjectCode* oc ) -{ - Elf_Shdr* shdr; - Elf_Sym* stab; - int j, nent, nstrtab, nsymtabs; - Elf_Word i, shnum, shstrndx; - char* sh_strtab; - - char* ehdrC = (char*)(oc->image); - Elf_Ehdr* ehdr = (Elf_Ehdr*)ehdrC; - - if (ehdr->e_ident[EI_MAG0] != ELFMAG0 || - ehdr->e_ident[EI_MAG1] != ELFMAG1 || - ehdr->e_ident[EI_MAG2] != ELFMAG2 || - ehdr->e_ident[EI_MAG3] != ELFMAG3) { - errorBelch("%s: not an ELF object", oc->fileName); - return 0; - } - - if (ehdr->e_ident[EI_CLASS] != ELFCLASS) { - errorBelch("%s: unsupported ELF format", oc->fileName); - return 0; - } - - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) { - IF_DEBUG(linker,debugBelch( "Is little-endian\n" )); - } else - if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) { - IF_DEBUG(linker,debugBelch( "Is big-endian\n" )); - } else { - errorBelch("%s: unknown endiannness", oc->fileName); - return 0; - } - - if (ehdr->e_type != ET_REL) { - errorBelch("%s: not a relocatable object (.o) file", oc->fileName); - return 0; - } - IF_DEBUG(linker, debugBelch( "Is a relocatable object (.o) file\n" )); - - IF_DEBUG(linker,debugBelch( "Architecture is " )); - switch (ehdr->e_machine) { -#ifdef EM_ARM - case EM_ARM: IF_DEBUG(linker,debugBelch( "arm" )); break; -#endif - case EM_386: IF_DEBUG(linker,debugBelch( "x86" )); break; -#ifdef EM_SPARC32PLUS - case EM_SPARC32PLUS: -#endif - case EM_SPARC: IF_DEBUG(linker,debugBelch( "sparc" )); break; -#ifdef EM_IA_64 - case EM_IA_64: IF_DEBUG(linker,debugBelch( "ia64" )); break; -#endif - case EM_PPC: IF_DEBUG(linker,debugBelch( "powerpc32" )); break; -#ifdef EM_X86_64 - case EM_X86_64: IF_DEBUG(linker,debugBelch( "x86_64" )); break; -#elif defined(EM_AMD64) - case EM_AMD64: IF_DEBUG(linker,debugBelch( "amd64" )); break; -#endif - default: IF_DEBUG(linker,debugBelch( "unknown" )); - errorBelch("%s: unknown architecture (e_machine == %d)" - , oc->fileName, ehdr->e_machine); - return 0; - } - - shnum = elf_shnum(ehdr); - IF_DEBUG(linker,debugBelch( - "\nSection header table: start %ld, n_entries %d, ent_size %d\n", - (long)ehdr->e_shoff, shnum, ehdr->e_shentsize )); - - ASSERT(ehdr->e_shentsize == sizeof(Elf_Shdr)); - - shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); - - shstrndx = elf_shstrndx(ehdr); - if (shstrndx == SHN_UNDEF) { - errorBelch("%s: no section header string table", oc->fileName); - return 0; - } else { - IF_DEBUG(linker,debugBelch( "Section header string table is section %d\n", - shstrndx)); - sh_strtab = ehdrC + shdr[shstrndx].sh_offset; - } - - for (i = 0; i < shnum; i++) { - IF_DEBUG(linker,debugBelch("%2d: ", i )); - IF_DEBUG(linker,debugBelch("type=%2d ", (int)shdr[i].sh_type )); - IF_DEBUG(linker,debugBelch("size=%4d ", (int)shdr[i].sh_size )); - IF_DEBUG(linker,debugBelch("offs=%4d ", (int)shdr[i].sh_offset )); - IF_DEBUG(linker,debugBelch(" (%p .. %p) ", - ehdrC + shdr[i].sh_offset, - ehdrC + shdr[i].sh_offset + shdr[i].sh_size - 1)); - -#define SECTION_INDEX_VALID(ndx) (ndx > SHN_UNDEF && ndx < shnum) - - switch (shdr[i].sh_type) { - - case SHT_REL: - case SHT_RELA: - IF_DEBUG(linker,debugBelch( shdr[i].sh_type == SHT_REL ? "Rel " : "RelA ")); - - if (!SECTION_INDEX_VALID(shdr[i].sh_link)) { - if (shdr[i].sh_link == SHN_UNDEF) - errorBelch("\n%s: relocation section #%d has no symbol table\n" - "This object file has probably been fully striped. " - "Such files cannot be linked.\n", - oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, i); - else - errorBelch("\n%s: relocation section #%d has an invalid link field (%d)\n", - oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, - i, shdr[i].sh_link); - return 0; - } - if (shdr[shdr[i].sh_link].sh_type != SHT_SYMTAB) { - errorBelch("\n%s: relocation section #%d does not link to a symbol table\n", - oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, i); - return 0; - } - if (!SECTION_INDEX_VALID(shdr[i].sh_info)) { - errorBelch("\n%s: relocation section #%d has an invalid info field (%d)\n", - oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, - i, shdr[i].sh_info); - return 0; - } - - break; - case SHT_SYMTAB: - IF_DEBUG(linker,debugBelch("Sym ")); - - if (!SECTION_INDEX_VALID(shdr[i].sh_link)) { - errorBelch("\n%s: symbol table section #%d has an invalid link field (%d)\n", - oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, - i, shdr[i].sh_link); - return 0; - } - if (shdr[shdr[i].sh_link].sh_type != SHT_STRTAB) { - errorBelch("\n%s: symbol table section #%d does not link to a string table\n", - oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, i); - - return 0; - } - break; - case SHT_STRTAB: IF_DEBUG(linker,debugBelch("Str ")); break; - default: IF_DEBUG(linker,debugBelch(" ")); break; - } - if (sh_strtab) { - IF_DEBUG(linker,debugBelch("sname=%s\n", sh_strtab + shdr[i].sh_name )); - } - } - - IF_DEBUG(linker,debugBelch( "\nString tables\n" )); - nstrtab = 0; - for (i = 0; i < shnum; i++) { - if (shdr[i].sh_type == SHT_STRTAB - /* Ignore the section header's string table. */ - && i != shstrndx - /* Ignore string tables named .stabstr, as they contain - debugging info. */ - && 0 != memcmp(".stabstr", sh_strtab + shdr[i].sh_name, 8) - ) { - IF_DEBUG(linker,debugBelch(" section %d is a normal string table\n", i )); - nstrtab++; - } - } - if (nstrtab == 0) { - IF_DEBUG(linker,debugBelch(" no normal string tables (potentially, but not necessarily a problem)\n")); - } -#if defined(SHN_XINDEX) - Elf_Word* shndxTable = get_shndx_table(ehdr); -#endif - nsymtabs = 0; - IF_DEBUG(linker,debugBelch( "Symbol tables\n" )); - for (i = 0; i < shnum; i++) { - if (shdr[i].sh_type != SHT_SYMTAB) continue; - IF_DEBUG(linker,debugBelch( "section %d is a symbol table\n", i )); - nsymtabs++; - stab = (Elf_Sym*) (ehdrC + shdr[i].sh_offset); - nent = shdr[i].sh_size / sizeof(Elf_Sym); - IF_DEBUG(linker,debugBelch( " number of entries is apparently %d (%ld rem)\n", - nent, - (long)shdr[i].sh_size % sizeof(Elf_Sym) - )); - if (0 != shdr[i].sh_size % sizeof(Elf_Sym)) { - errorBelch("%s: non-integral number of symbol table entries", oc->fileName); - return 0; - } - for (j = 0; j < nent; j++) { - Elf_Word secno = stab[j].st_shndx; -#if defined(SHN_XINDEX) - /* See Note [Many ELF Sections] */ - if (secno == SHN_XINDEX) { - ASSERT(shndxTable); - secno = shndxTable[j]; - } -#endif - IF_DEBUG(linker,debugBelch(" %2d ", j )); - IF_DEBUG(linker,debugBelch(" sec=%-5d size=%-3d val=%5p ", - (int)secno, - (int)stab[j].st_size, - (char*)stab[j].st_value )); - - IF_DEBUG(linker,debugBelch("type=" )); - switch (ELF_ST_TYPE(stab[j].st_info)) { - case STT_NOTYPE: IF_DEBUG(linker,debugBelch("notype " )); break; - case STT_OBJECT: IF_DEBUG(linker,debugBelch("object " )); break; - case STT_FUNC : IF_DEBUG(linker,debugBelch("func " )); break; - case STT_SECTION: IF_DEBUG(linker,debugBelch("section" )); break; - case STT_FILE: IF_DEBUG(linker,debugBelch("file " )); break; - default: IF_DEBUG(linker,debugBelch("? " )); break; - } - IF_DEBUG(linker,debugBelch(" " )); - - IF_DEBUG(linker,debugBelch("bind=" )); - switch (ELF_ST_BIND(stab[j].st_info)) { - case STB_LOCAL : IF_DEBUG(linker,debugBelch("local " )); break; - case STB_GLOBAL: IF_DEBUG(linker,debugBelch("global" )); break; - case STB_WEAK : IF_DEBUG(linker,debugBelch("weak " )); break; - default: IF_DEBUG(linker,debugBelch("? " )); break; - } - IF_DEBUG(linker,debugBelch(" " )); - - IF_DEBUG(linker,debugBelch("other=%2x ", stab[j].st_other )); - IF_DEBUG(linker,debugBelch("name=%s [%x]\n", - ehdrC + shdr[shdr[i].sh_link].sh_offset - + stab[j].st_name, stab[j].st_name )); - } - } - - if (nsymtabs == 0) { - // Not having a symbol table is not in principle a problem. - // When an object file has no symbols then the 'strip' program - // typically will remove the symbol table entirely. - IF_DEBUG(linker,debugBelch(" no symbol tables (potentially, but not necessarily a problem)\n")); - } - - return 1; -} - -/* Figure out what kind of section it is. Logic derived from - Figure 1.14 ("Special Sections") of the ELF document - ("Portable Formats Specification, Version 1.1"). */ -static int getSectionKind_ELF( Elf_Shdr *hdr, int *is_bss ) -{ - *is_bss = FALSE; - - if (hdr->sh_type == SHT_PROGBITS - && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_EXECINSTR)) { - /* .text-style section */ - return SECTIONKIND_CODE_OR_RODATA; - } - - if (hdr->sh_type == SHT_PROGBITS - && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_WRITE)) { - /* .data-style section */ - return SECTIONKIND_RWDATA; - } - - if (hdr->sh_type == SHT_PROGBITS - && (hdr->sh_flags & SHF_ALLOC) && !(hdr->sh_flags & SHF_WRITE)) { - /* .rodata-style section */ - return SECTIONKIND_CODE_OR_RODATA; - } -#ifndef openbsd_HOST_OS - if (hdr->sh_type == SHT_INIT_ARRAY - && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_WRITE)) { - /* .init_array section */ - return SECTIONKIND_INIT_ARRAY; - } -#endif /* not OpenBSD */ - if (hdr->sh_type == SHT_NOBITS - && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_WRITE)) { - /* .bss-style section */ - *is_bss = TRUE; - return SECTIONKIND_RWDATA; - } - - return SECTIONKIND_OTHER; -} - -static void * -mapObjectFileSection (int fd, Elf_Word offset, Elf_Word size, - void **mapped_start, StgWord *mapped_size, - StgWord *mapped_offset) -{ - void *p; - size_t pageOffset, pageSize; - - pageOffset = roundDownToPage(offset); - pageSize = roundUpToPage(offset-pageOffset+size); - p = mmapForLinker(pageSize, 0, fd, pageOffset); - if (p == NULL) return NULL; - *mapped_size = pageSize; - *mapped_offset = pageOffset; - *mapped_start = p; - return (void*)((StgWord)p + offset - pageOffset); -} - -static int -ocGetNames_ELF ( ObjectCode* oc ) -{ - Elf_Word i; - int j, nent, result, fd = -1; - Elf_Sym* stab; - - char* ehdrC = (char*)(oc->image); - Elf_Ehdr* ehdr = (Elf_Ehdr*)ehdrC; - char* strtab; - Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); - Section * sections; -#if defined(SHN_XINDEX) - Elf_Word* shndxTable = get_shndx_table(ehdr); -#endif - const Elf_Word shnum = elf_shnum(ehdr); - - ASSERT(symhash != NULL); - - sections = (Section*)stgCallocBytes(sizeof(Section), shnum, - "ocGetNames_ELF(sections)"); - oc->sections = sections; - oc->n_sections = shnum; - - - if (oc->imageMapped) { -#if defined(openbsd_HOST_OS) - fd = open(oc->fileName, O_RDONLY, S_IRUSR); -#else - fd = open(oc->fileName, O_RDONLY); -#endif - if (fd == -1) { - errorBelch("loadObj: can't open %" PATH_FMT, oc->fileName); - return 0; - } - } - - for (i = 0; i < shnum; i++) { - int is_bss = FALSE; - SectionKind kind = getSectionKind_ELF(&shdr[i], &is_bss); - SectionAlloc alloc = SECTION_NOMEM; - void *start = NULL, *mapped_start = NULL; - StgWord mapped_size = 0, mapped_offset = 0; - StgWord size = shdr[i].sh_size; - StgWord offset = shdr[i].sh_offset; - - if (is_bss && size > 0) { - /* This is a non-empty .bss section. Allocate zeroed space for - it, and set its .sh_offset field such that - ehdrC + .sh_offset == addr_of_zeroed_space. */ - alloc = SECTION_MALLOC; - start = stgCallocBytes(1, size, "ocGetNames_ELF(BSS)"); - mapped_start = start; - /* - debugBelch("BSS section at 0x%x, size %d\n", - zspace, shdr[i].sh_size); - */ - } - - else if (kind != SECTIONKIND_OTHER && size > 0) { - if (USE_CONTIGUOUS_MMAP) { - // already mapped. - start = oc->image + offset; - alloc = SECTION_NOMEM; - } - // use the m32 allocator if either the image is not mapped - // (i.e. we cannot map the secions separately), or if the section - // size is small. - else if (!oc->imageMapped || size < getPageSize() / 3) { - start = m32_alloc(size, 8); - if (start == NULL) goto fail; - memcpy(start, oc->image + offset, size); - alloc = SECTION_M32; - } else { - start = mapObjectFileSection(fd, offset, size, - &mapped_start, &mapped_size, - &mapped_offset); - if (start == NULL) goto fail; - alloc = SECTION_MMAP; - } - addProddableBlock(oc, start, size); - } - - addSection(§ions[i], kind, alloc, start, size, - mapped_offset, mapped_start, mapped_size); - - if (shdr[i].sh_type != SHT_SYMTAB) continue; - - /* copy stuff into this module's object symbol table */ - stab = (Elf_Sym*) (ehdrC + offset); - strtab = ehdrC + shdr[shdr[i].sh_link].sh_offset; - nent = shdr[i].sh_size / sizeof(Elf_Sym); - - oc->n_symbols = nent; - oc->symbols = stgCallocBytes(oc->n_symbols, sizeof(SymbolName*), - "ocGetNames_ELF(oc->symbols)"); - // Note calloc: if we fail partway through initializing symbols, we need - // to undo the additions to the symbol table so far. We know which ones - // have been added by whether the entry is NULL or not. - - //TODO: we ignore local symbols anyway right? So we can use the - // shdr[i].sh_info to get the index of the first non-local symbol - // ie we should use j = shdr[i].sh_info - for (j = 0; j < nent; j++) { - - char isLocal = FALSE; /* avoids uninit-var warning */ - HsBool isWeak = HS_BOOL_FALSE; - SymbolAddr* ad = NULL; - SymbolName* nm = strtab + stab[j].st_name; - unsigned short shndx = stab[j].st_shndx; - Elf_Word secno; - - /* See Note [Many ELF Sections] */ - /* Note that future checks for special SHN_* numbers should check the - * shndx variable, not the section number in secno. Sections with the - * real number in the SHN_LORESERVE..HIRESERVE range will have shndx - * SHN_XINDEX and a secno with one of the reserved values. */ - secno = shndx; -#if defined(SHN_XINDEX) - if (shndx == SHN_XINDEX) { - ASSERT(shndxTable); - secno = shndxTable[j]; - } -#endif - /* Figure out if we want to add it; if so, set ad to its - address. Otherwise leave ad == NULL. */ - - if (shndx == SHN_COMMON) { - isLocal = FALSE; - ad = stgCallocBytes(1, stab[j].st_size, "ocGetNames_ELF(COMMON)"); - /* - debugBelch("COMMON symbol, size %d name %s\n", - stab[j].st_size, nm); - */ - /* Pointless to do addProddableBlock() for this area, - since the linker should never poke around in it. */ - } - else - if ( ( ELF_ST_BIND(stab[j].st_info)==STB_GLOBAL - || ELF_ST_BIND(stab[j].st_info)==STB_LOCAL - || ELF_ST_BIND(stab[j].st_info)==STB_WEAK - ) - /* and not an undefined symbol */ - && shndx != SHN_UNDEF - /* and not in a "special section" */ - && (shndx < SHN_LORESERVE -#if defined(SHN_XINDEX) - || shndx == SHN_XINDEX -#endif - ) - && - /* and it's a not a section or string table or anything silly */ - ( ELF_ST_TYPE(stab[j].st_info)==STT_FUNC || - ELF_ST_TYPE(stab[j].st_info)==STT_OBJECT || - ELF_ST_TYPE(stab[j].st_info)==STT_NOTYPE - ) - ) { - /* Section 0 is the undefined section, hence > and not >=. */ - ASSERT(secno > 0 && secno < shnum); - /* - if (shdr[secno].sh_type == SHT_NOBITS) { - debugBelch(" BSS symbol, size %d off %d name %s\n", - stab[j].st_size, stab[j].st_value, nm); - } - */ - ad = (SymbolAddr*)((intptr_t)sections[secno].start + - (intptr_t)stab[j].st_value); - if (ELF_ST_BIND(stab[j].st_info)==STB_LOCAL) { - isLocal = TRUE; - isWeak = FALSE; - } else { /* STB_GLOBAL or STB_WEAK */ -#ifdef ELF_FUNCTION_DESC - /* dlsym() and the initialisation table both give us function - * descriptors, so to be consistent we store function descriptors - * in the symbol table */ - if (ELF_ST_TYPE(stab[j].st_info) == STT_FUNC) - ad = (SymbolAddr*)allocateFunctionDesc((Elf_Addr)ad); -#endif - IF_DEBUG(linker,debugBelch( "addOTabName(GLOB): %10p %s %s\n", - ad, oc->fileName, nm )); - isLocal = FALSE; - isWeak = (ELF_ST_BIND(stab[j].st_info)==STB_WEAK); - } - } - - /* And the decision is ... */ - - oc->symbols[j] = nm; - - if (ad != NULL) { - ASSERT(nm != NULL); - /* Acquire! */ - if (isLocal) { - /* Ignore entirely. */ - oc->symbols[j] = NULL; - } else { - - if (isWeak == HS_BOOL_TRUE) { - setWeakSymbol(oc, nm); - } - - if (! ghciInsertSymbolTable(oc->fileName, symhash, - nm, ad, isWeak, oc)) { - goto fail; - } - } - } else { - /* Skip. */ - IF_DEBUG(linker,debugBelch( "skipping `%s'\n", - nm )); - - /* We're skipping the symbol, but if we ever load this - object file we'll want to skip it then too. */ - oc->symbols[j] = NULL; - - /* - debugBelch( - "skipping bind = %d, type = %d, secno = %d `%s'\n", - (int)ELF_ST_BIND(stab[j].st_info), - (int)ELF_ST_TYPE(stab[j].st_info), - (int)secno, - nm - ); - */ - } - - } - } - - result = 1; - goto end; - -fail: - result = 0; - goto end; - -end: - if (fd >= 0) close(fd); - return result; -} - -#ifdef arm_HOST_ARCH -// TODO: These likely belong in a library somewhere - -// Signed extend a number to a 32-bit int. -static inline StgInt32 sign_extend32(uint32_t bits, StgWord32 x) { - return ((StgInt32) (x << (32 - bits))) >> (32 - bits); -} - -// Does the given signed integer fit into the given bit width? -static inline StgBool is_int(uint32_t bits, StgInt32 x) { - return bits > 32 || (-(1 << (bits-1)) <= x - && x < (1 << (bits-1))); -} -#endif - -/* Do ELF relocations which lack an explicit addend. All x86-linux - and arm-linux relocations appear to be of this form. */ -static int -do_Elf_Rel_relocations ( ObjectCode* oc, char* ehdrC, - Elf_Shdr* shdr, int shnum ) -{ - int j; - SymbolName* symbol; - Elf_Word* targ; - Elf_Rel* rtab = (Elf_Rel*) (ehdrC + shdr[shnum].sh_offset); - Elf_Sym* stab; - char* strtab; - int nent = shdr[shnum].sh_size / sizeof(Elf_Rel); - int target_shndx = shdr[shnum].sh_info; - int symtab_shndx = shdr[shnum].sh_link; - int strtab_shndx = shdr[symtab_shndx].sh_link; -#if defined(SHN_XINDEX) - Elf_Word* shndx_table = get_shndx_table((Elf_Ehdr*)ehdrC); -#endif - - stab = (Elf_Sym*) (ehdrC + shdr[ symtab_shndx ].sh_offset); - strtab= (char*) (ehdrC + shdr[ strtab_shndx ].sh_offset); - targ = (Elf_Word*)oc->sections[target_shndx].start; - IF_DEBUG(linker,debugBelch( "relocations for section %d using symtab %d and strtab %d\n", - target_shndx, symtab_shndx, strtab_shndx )); - - /* Skip sections that we're not interested in. */ - if (oc->sections[target_shndx].kind == SECTIONKIND_OTHER) { - IF_DEBUG(linker,debugBelch( "skipping (target section not loaded)")); - return 1; - } - - for (j = 0; j < nent; j++) { - Elf_Addr offset = rtab[j].r_offset; - Elf_Addr info = rtab[j].r_info; - - Elf_Addr P = ((Elf_Addr)targ) + offset; - Elf_Word* pP = (Elf_Word*)P; -#if defined(i386_HOST_ARCH) || defined(DEBUG) - Elf_Addr A = *pP; -#endif - Elf_Addr S; - void* S_tmp; -#ifdef i386_HOST_ARCH - Elf_Addr value; -#endif -#ifdef arm_HOST_ARCH - int is_target_thm=0, T=0; -#endif - - IF_DEBUG(linker,debugBelch( "Rel entry %3d is raw(%6p %6p): ", - j, (void*)offset, (void*)info )); - if (!info) { - IF_DEBUG(linker,debugBelch( " ZERO" )); - S = 0; - } else { - Elf_Sym sym = stab[ELF_R_SYM(info)]; - /* First see if it is a local symbol. */ - if (ELF_ST_BIND(sym.st_info) == STB_LOCAL) { - /* Yes, so we can get the address directly from the ELF symbol - table. */ - symbol = sym.st_name==0 ? "(noname)" : strtab+sym.st_name; - /* See Note [Many ELF Sections] */ - Elf_Word secno = sym.st_shndx; -#if defined(SHN_XINDEX) - if (secno == SHN_XINDEX) { - ASSERT(shndx_table); - secno = shndx_table[ELF_R_SYM(info)]; - } -#endif - S = (Elf_Addr)oc->sections[ secno ].start + - stab[ELF_R_SYM(info)].st_value; - } else { - symbol = strtab + sym.st_name; - S_tmp = lookupSymbol_( symbol ); - S = (Elf_Addr)S_tmp; - } - if (!S) { - errorBelch("%s: unknown symbol `%s'", oc->fileName, symbol); - return 0; - } - IF_DEBUG(linker,debugBelch( "`%s' resolves to %p\n", symbol, (void*)S )); - -#ifdef arm_HOST_ARCH - // Thumb instructions have bit 0 of symbol's st_value set - is_target_thm = S & 0x1; - - T = sym.st_info & STT_FUNC && is_target_thm; - - // Make sure we clear bit 0. Strictly speaking we should have done - // this to st_value above but I believe alignment requirements should - // ensure that no instructions start on an odd address - S &= ~1; -#endif - } - - int reloc_type = ELF_R_TYPE(info); - IF_DEBUG(linker,debugBelch( "Reloc: P = %p S = %p A = %p type=%d\n", - (void*)P, (void*)S, (void*)A, reloc_type )); - checkProddableBlock ( oc, pP, sizeof(Elf_Word) ); - -#ifdef i386_HOST_ARCH - value = S + A; -#endif - - switch (reloc_type) { -# ifdef i386_HOST_ARCH - case R_386_32: *pP = value; break; - case R_386_PC32: *pP = value - P; break; -# endif - -# ifdef arm_HOST_ARCH - case R_ARM_ABS32: - case R_ARM_TARGET1: // Specified by Linux ARM ABI to be equivalent to ABS32 - *(Elf32_Word *)P += S; - *(Elf32_Word *)P |= T; - break; - - case R_ARM_REL32: - *(Elf32_Word *)P += S; - *(Elf32_Word *)P |= T; - *(Elf32_Word *)P -= P; - break; - - case R_ARM_CALL: - case R_ARM_JUMP24: - { - // N.B. LLVM's LLD linker's relocation implement is a fantastic - // resource - StgWord32 *word = (StgWord32 *)P; - StgInt32 imm = (*word & ((1<<24)-1)) << 2; - - const StgBool is_blx = (*word & 0xf0000000) == 0xf0000000; - const StgWord32 hBit = is_blx ? ((*word >> 24) & 1) : 0; - imm |= hBit << 1; - - // Sign extend to 32 bits - // I would have thought this would be 24 bits but LLD uses 26 here. - // Hmm. - imm = sign_extend32(26, imm); - - StgWord32 result = ((S + imm) | T) - P; - - const StgBool overflow = !is_int(26, (StgInt32) result); - - // Handle overflow and Thumb interworking - const StgBool needs_veneer = (is_target_thm && ELF_R_TYPE(info) == R_ARM_JUMP24) || overflow; - if (needs_veneer) { - // Generate veneer - // The +8 below is to undo the PC-bias compensation done by the object producer - SymbolExtra *extra = makeArmSymbolExtra(oc, ELF_R_SYM(info), S+imm+8, 0, is_target_thm); - // The -8 below is to compensate for PC bias - result = (StgWord32) ((StgInt32) extra->jumpIsland - P - 8); - result &= ~1; // Clear thumb indicator bit - if (!is_int(26, (StgInt32) result)) { - errorBelch("Unable to fixup overflow'd R_ARM_CALL: jump island=%p, reloc=%p\n", - (void*) extra->jumpIsland, (void*) P); - return 0; - } - } - - // Update the branch target - const StgWord32 imm24 = (result & 0x03fffffc) >> 2; - *word = (*word & ~0x00ffffff) - | (imm24 & 0x00ffffff); - - // Change the relocated branch into a BLX if necessary - const StgBool switch_mode = is_target_thm && (reloc_type == R_ARM_CALL); - if (!needs_veneer && switch_mode) { - const StgWord32 hBit = (result & 0x2) >> 1; - // Change instruction to BLX - *word = (*word & ~0xFF000000) | ((0xfa | hBit) << 24); - IF_DEBUG(linker, debugBelch("Changed BL to BLX at %p\n", word)); - } - break; - } - - case R_ARM_MOVT_ABS: - case R_ARM_MOVW_ABS_NC: - { - StgWord32 *word = (StgWord32 *)P; - StgWord32 imm12 = *word & 0xfff; - StgWord32 imm4 = (*word >> 16) & 0xf; - StgInt32 offset = imm4 << 12 | imm12; - StgWord32 result = (S + offset) | T; - - if (reloc_type == R_ARM_MOVT_ABS) - result = (result & 0xffff0000) >> 16; - - StgWord32 result12 = result & 0xfff; - StgWord32 result4 = (result >> 12) & 0xf; - *word = (*word & ~0xf0fff) | (result4 << 16) | result12; - break; - } - - case R_ARM_THM_CALL: - case R_ARM_THM_JUMP24: - { - StgWord16 *upper = (StgWord16 *)P; - StgWord16 *lower = (StgWord16 *)(P + 2); - - int overflow; - int to_thm = (*lower >> 12) & 1; - int sign = (*upper >> 10) & 1; - int j1, j2, i1, i2; - - // Decode immediate value - j1 = (*lower >> 13) & 1; i1 = ~(j1 ^ sign) & 1; - j2 = (*lower >> 11) & 1; i2 = ~(j2 ^ sign) & 1; - StgInt32 imm = (sign << 24) - | (i1 << 23) - | (i2 << 22) - | ((*upper & 0x03ff) << 12) - | ((*lower & 0x07ff) << 1); - - // Sign extend 25 to 32 bits - if (imm & 0x01000000) - imm -= 0x02000000; - - offset = ((imm + S) | T) - P; - overflow = offset <= (StgWord32)0xff000000 || offset >= (StgWord32)0x01000000; - - if ((!is_target_thm && ELF_R_TYPE(info) == R_ARM_THM_JUMP24) || overflow) { - // Generate veneer - SymbolExtra *extra = makeArmSymbolExtra(oc, ELF_R_SYM(info), S+imm+4, 1, is_target_thm); - offset = (StgWord32) &extra->jumpIsland - P - 4; - sign = offset >> 31; - to_thm = 1; - } else if (!is_target_thm && ELF_R_TYPE(info) == R_ARM_THM_CALL) { - offset &= ~0x3; - to_thm = 0; - } - - // Reencode instruction - i1 = ~(offset >> 23) & 1; j1 = sign ^ i1; - i2 = ~(offset >> 22) & 1; j2 = sign ^ i2; - *upper = ( (*upper & 0xf800) - | (sign << 10) - | ((offset >> 12) & 0x03ff) ); - *lower = ( (*lower & 0xd000) - | (j1 << 13) - | (to_thm << 12) - | (j2 << 11) - | ((offset >> 1) & 0x07ff) ); - break; - } - - case R_ARM_THM_MOVT_ABS: - case R_ARM_THM_MOVW_ABS_NC: - { - StgWord16 *upper = (StgWord16 *)P; - StgWord16 *lower = (StgWord16 *)(P + 2); - StgInt32 offset = ((*upper & 0x000f) << 12) - | ((*upper & 0x0400) << 1) - | ((*lower & 0x7000) >> 4) - | (*lower & 0x00ff); - - offset = (offset ^ 0x8000) - 0x8000; // Sign extend - offset += S; - if (ELF_R_TYPE(info) == R_ARM_THM_MOVW_ABS_NC) - offset |= T; - else if (ELF_R_TYPE(info) == R_ARM_THM_MOVT_ABS) - offset >>= 16; - - *upper = ( (*upper & 0xfbf0) - | ((offset & 0xf000) >> 12) - | ((offset & 0x0800) >> 1) ); - *lower = ( (*lower & 0x8f00) - | ((offset & 0x0700) << 4) - | (offset & 0x00ff) ); - break; - } - - case R_ARM_THM_JUMP8: - { - StgWord16 *word = (StgWord16 *)P; - StgWord offset = *word & 0x01fe; - offset += S - P; - if (!is_target_thm) { - errorBelch("%s: Thumb to ARM transition with JUMP8 relocation not supported\n", - oc->fileName); - return 0; - } - - *word = (*word & ~0x01fe) - | (offset & 0x01fe); - break; - } - - case R_ARM_THM_JUMP11: - { - StgWord16 *word = (StgWord16 *)P; - StgWord offset = *word & 0x0ffe; - offset += S - P; - if (!is_target_thm) { - errorBelch("%s: Thumb to ARM transition with JUMP11 relocation not supported\n", - oc->fileName); - return 0; - } - - *word = (*word & ~0x0ffe) - | (offset & 0x0ffe); - break; - } - -# endif // arm_HOST_ARCH - - default: - errorBelch("%s: unhandled ELF relocation(Rel) type %" FMT_Word "\n", - oc->fileName, (W_)ELF_R_TYPE(info)); - return 0; - } - - } - return 1; -} - -/* Do ELF relocations for which explicit addends are supplied. - sparc-solaris relocations appear to be of this form. */ -static int -do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC, - Elf_Shdr* shdr, int shnum ) -{ - int j; - SymbolName* symbol = NULL; - Elf_Rela* rtab = (Elf_Rela*) (ehdrC + shdr[shnum].sh_offset); - Elf_Sym* stab; - char* strtab; - int nent = shdr[shnum].sh_size / sizeof(Elf_Rela); - int symtab_shndx = shdr[shnum].sh_link; - int strtab_shndx = shdr[symtab_shndx].sh_link; - int target_shndx = shdr[shnum].sh_info; -#if defined(SHN_XINDEX) - Elf_Word* shndx_table = get_shndx_table((Elf_Ehdr*)ehdrC); -#endif -#if defined(DEBUG) || defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) - /* This #ifdef only serves to avoid unused-var warnings. */ - Elf_Addr targ = (Elf_Addr) oc->sections[target_shndx].start; -#endif - - stab = (Elf_Sym*) (ehdrC + shdr[ symtab_shndx ].sh_offset); - strtab= (char*) (ehdrC + shdr[ strtab_shndx ].sh_offset); - - IF_DEBUG(linker,debugBelch( "relocations for section %d using symtab %d\n", - target_shndx, symtab_shndx )); - - /* Skip sections that we're not interested in. */ - if (oc->sections[target_shndx].kind == SECTIONKIND_OTHER) { - IF_DEBUG(linker,debugBelch( "skipping (target section not loaded)")); - return 1; - } - - for (j = 0; j < nent; j++) { -#if defined(DEBUG) || defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) - /* This #ifdef only serves to avoid unused-var warnings. */ - Elf_Addr offset = rtab[j].r_offset; - Elf_Addr P = targ + offset; - Elf_Addr A = rtab[j].r_addend; -#endif -#if defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) - Elf_Addr value; -#endif - Elf_Addr info = rtab[j].r_info; - Elf_Addr S; - void* S_tmp; -# if defined(sparc_HOST_ARCH) - Elf_Word* pP = (Elf_Word*)P; - Elf_Word w1, w2; -# elif defined(powerpc_HOST_ARCH) - Elf_Sword delta; -# endif - - IF_DEBUG(linker,debugBelch( "Rel entry %3d is raw(%6p %6p %6p) ", - j, (void*)offset, (void*)info, - (void*)A )); - if (!info) { - IF_DEBUG(linker,debugBelch( " ZERO" )); - S = 0; - } else { - Elf_Sym sym = stab[ELF_R_SYM(info)]; - /* First see if it is a local symbol. */ - if (ELF_ST_BIND(sym.st_info) == STB_LOCAL) { - /* Yes, so we can get the address directly from the ELF symbol - table. */ - symbol = sym.st_name==0 ? "(noname)" : strtab+sym.st_name; - /* See Note [Many ELF Sections] */ - Elf_Word secno = sym.st_shndx; -#if defined(SHN_XINDEX) - if (secno == SHN_XINDEX) { - secno = shndx_table[ELF_R_SYM(info)]; - } -#endif - S = (Elf_Addr)oc->sections[secno].start - + stab[ELF_R_SYM(info)].st_value; -#ifdef ELF_FUNCTION_DESC - /* Make a function descriptor for this function */ - if (S && ELF_ST_TYPE(sym.st_info) == STT_FUNC) { - S = allocateFunctionDesc(S + A); - A = 0; - } -#endif - } else { - /* No, so look up the name in our global table. */ - symbol = strtab + sym.st_name; - S_tmp = lookupSymbol_( symbol ); - S = (Elf_Addr)S_tmp; - -#ifdef ELF_FUNCTION_DESC - /* If a function, already a function descriptor - we would - have to copy it to add an offset. */ - if (S && (ELF_ST_TYPE(sym.st_info) == STT_FUNC) && (A != 0)) - errorBelch("%s: function %s with addend %p", oc->fileName, symbol, (void *)A); -#endif - } - if (!S) { - errorBelch("%s: unknown symbol `%s'", oc->fileName, symbol); - return 0; - } - IF_DEBUG(linker,debugBelch( "`%s' resolves to %p\n", symbol, (void*)S )); - } - -#if defined(DEBUG) || defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) \ - || defined(x86_64_HOST_ARCH) - IF_DEBUG(linker,debugBelch("Reloc: P = %p S = %p A = %p\n", - (void*)P, (void*)S, (void*)A )); - checkProddableBlock(oc, (void*)P, sizeof(Elf_Word)); -#endif - -#if defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) - value = S + A; -#endif - - switch (ELF_R_TYPE(info)) { -# if defined(sparc_HOST_ARCH) - case R_SPARC_WDISP30: - w1 = *pP & 0xC0000000; - w2 = (Elf_Word)((value - P) >> 2); - ASSERT((w2 & 0xC0000000) == 0); - w1 |= w2; - *pP = w1; - break; - case R_SPARC_HI22: - w1 = *pP & 0xFFC00000; - w2 = (Elf_Word)(value >> 10); - ASSERT((w2 & 0xFFC00000) == 0); - w1 |= w2; - *pP = w1; - break; - case R_SPARC_LO10: - w1 = *pP & ~0x3FF; - w2 = (Elf_Word)(value & 0x3FF); - ASSERT((w2 & ~0x3FF) == 0); - w1 |= w2; - *pP = w1; - break; - - /* According to the Sun documentation: - R_SPARC_UA32 - This relocation type resembles R_SPARC_32, except it refers to an - unaligned word. That is, the word to be relocated must be treated - as four separate bytes with arbitrary alignment, not as a word - aligned according to the architecture requirements. - */ - case R_SPARC_UA32: - w2 = (Elf_Word)value; - - // SPARC doesn't do misaligned writes of 32 bit words, - // so we have to do this one byte-at-a-time. - char *pPc = (char*)pP; - pPc[0] = (char) ((Elf_Word)(w2 & 0xff000000) >> 24); - pPc[1] = (char) ((Elf_Word)(w2 & 0x00ff0000) >> 16); - pPc[2] = (char) ((Elf_Word)(w2 & 0x0000ff00) >> 8); - pPc[3] = (char) ((Elf_Word)(w2 & 0x000000ff)); - break; - - case R_SPARC_32: - w2 = (Elf_Word)value; - *pP = w2; - break; -# elif defined(powerpc_HOST_ARCH) - case R_PPC_ADDR16_LO: - *(Elf32_Half*) P = value; - break; - - case R_PPC_ADDR16_HI: - *(Elf32_Half*) P = value >> 16; - break; - - case R_PPC_ADDR16_HA: - *(Elf32_Half*) P = (value + 0x8000) >> 16; - break; - - case R_PPC_ADDR32: - *(Elf32_Word *) P = value; - break; - - case R_PPC_REL32: - *(Elf32_Word *) P = value - P; - break; - - case R_PPC_PLTREL24: - value -= 0x8000; /* See Note [.LCTOC1 in PPC PIC code] */ - /* fallthrough */ - case R_PPC_REL24: - delta = value - P; - - if( delta << 6 >> 6 != delta ) - { - value = (Elf_Addr) (&makeSymbolExtra( oc, ELF_R_SYM(info), value ) - ->jumpIsland); - delta = value - P; - - if( value == 0 || delta << 6 >> 6 != delta ) - { - barf( "Unable to make SymbolExtra for #%d", - ELF_R_SYM(info) ); - return 0; - } - } - - *(Elf_Word *) P = (*(Elf_Word *) P & 0xfc000003) - | (delta & 0x3fffffc); - break; - - case R_PPC_REL16_LO: - *(Elf32_Half*) P = value - P; - break; - - case R_PPC_REL16_HI: - *(Elf32_Half*) P = (value - P) >> 16; - break; - - case R_PPC_REL16_HA: - *(Elf32_Half*) P = (value + 0x8000 - P) >> 16; - break; -# endif - -#if x86_64_HOST_ARCH - case R_X86_64_64: - *(Elf64_Xword *)P = value; - break; - - case R_X86_64_PC32: - { -#if defined(ALWAYS_PIC) - barf("R_X86_64_PC32 relocation, but ALWAYS_PIC."); -#else - StgInt64 off = value - P; - if (off >= 0x7fffffffL || off < -0x80000000L) { - if (X86_64_ELF_NONPIC_HACK) { - StgInt64 pltAddress = - (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) - -> jumpIsland; - off = pltAddress + A - P; - } else { - errorBelch("R_X86_64_PC32 relocation out of range: %s = %" - PRId64 "d\nRecompile %s with -fPIC.", - symbol, off, oc->fileName ); - return 0; - } - } - *(Elf64_Word *)P = (Elf64_Word)off; -#endif - break; - } - - case R_X86_64_PC64: - { - StgInt64 off = value - P; - *(Elf64_Word *)P = (Elf64_Word)off; - break; - } - - case R_X86_64_32: -#if defined(ALWAYS_PIC) - barf("R_X86_64_32 relocation, but ALWAYS_PIC."); -#else - if (value >= 0x7fffffffL) { - if (X86_64_ELF_NONPIC_HACK) { - StgInt64 pltAddress = - (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) - -> jumpIsland; - value = pltAddress + A; - } else { - errorBelch("R_X86_64_32 relocation out of range: %s = %" - PRId64 "d\nRecompile %s with -fPIC.", - symbol, value, oc->fileName ); - return 0; - } - } - *(Elf64_Word *)P = (Elf64_Word)value; -#endif - break; - - case R_X86_64_32S: -#if defined(ALWAYS_PIC) - barf("R_X86_64_32S relocation, but ALWAYS_PIC."); -#else - if ((StgInt64)value > 0x7fffffffL || (StgInt64)value < -0x80000000L) { - if (X86_64_ELF_NONPIC_HACK) { - StgInt64 pltAddress = - (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) - -> jumpIsland; - value = pltAddress + A; - } else { - errorBelch("R_X86_64_32S relocation out of range: %s = %" - PRId64 "d\nRecompile %s with -fPIC.", - symbol, value, oc->fileName ); - return 0; - } - } - *(Elf64_Sword *)P = (Elf64_Sword)value; -#endif - break; -/* These two relocations were introduced in glibc 2.23 and binutils 2.26. - But in order to use them the system which compiles the bindist for GHC needs - to have glibc >= 2.23. So only use them if they're defined. */ -#if defined(R_X86_64_REX_GOTPCRELX) && defined(R_X86_64_GOTPCRELX) - case R_X86_64_REX_GOTPCRELX: - case R_X86_64_GOTPCRELX: -#endif - case R_X86_64_GOTPCREL: - { - StgInt64 gotAddress = (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S)->addr; - StgInt64 off = gotAddress + A - P; - *(Elf64_Word *)P = (Elf64_Word)off; - break; - } -#if defined(dragonfly_HOST_OS) - case R_X86_64_GOTTPOFF: - { -#if defined(ALWAYS_PIC) - barf("R_X86_64_GOTTPOFF relocation, but ALWAYS_PIC."); -#else - /* determine the offset of S to the current thread's tls - area - XXX: Move this to the beginning of function */ - struct tls_info ti; - get_tls_area(0, &ti, sizeof(ti)); - /* make entry in GOT that contains said offset */ - StgInt64 gotEntry = (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), - (S - (Elf64_Addr)(ti.base)))->addr; - *(Elf64_Word *)P = gotEntry + A - P; -#endif - break; - } -#endif - - - - case R_X86_64_PLT32: - { -#if defined(ALWAYS_PIC) - barf("R_X86_64_PLT32 relocation, but ALWAYS_PIC."); -#else - StgInt64 off = value - P; - if (off >= 0x7fffffffL || off < -0x80000000L) { - StgInt64 pltAddress = (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) - -> jumpIsland; - off = pltAddress + A - P; - } - *(Elf64_Word *)P = (Elf64_Word)off; -#endif - break; - } -#endif - - default: - errorBelch("%s: unhandled ELF relocation(RelA) type %" FMT_Word "\n", - oc->fileName, (W_)ELF_R_TYPE(info)); - return 0; - } - - } - return 1; -} - -static int -ocResolve_ELF ( ObjectCode* oc ) -{ - int ok; - Elf_Word i; - char* ehdrC = (char*)(oc->image); - Elf_Ehdr* ehdr = (Elf_Ehdr*) ehdrC; - Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); - const Elf_Word shnum = elf_shnum(ehdr); - - /* Process the relocation sections. */ - for (i = 0; i < shnum; i++) { - if (shdr[i].sh_type == SHT_REL) { - ok = do_Elf_Rel_relocations ( oc, ehdrC, shdr, i ); - if (!ok) return ok; - } - else - if (shdr[i].sh_type == SHT_RELA) { - ok = do_Elf_Rela_relocations ( oc, ehdrC, shdr, i ); - if (!ok) return ok; - } - } - -#if defined(powerpc_HOST_ARCH) || defined(arm_HOST_ARCH) - ocFlushInstructionCache( oc ); -#endif - - return 1; -} - -static int ocRunInit_ELF( ObjectCode *oc ) -{ - Elf_Word i; - char* ehdrC = (char*)(oc->image); - Elf_Ehdr* ehdr = (Elf_Ehdr*) ehdrC; - Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); - char* sh_strtab = ehdrC + shdr[elf_shstrndx(ehdr)].sh_offset; - int argc, envc; - char **argv, **envv; - - getProgArgv(&argc, &argv); - getProgEnvv(&envc, &envv); - - // XXX Apparently in some archs .init may be something - // special! See DL_DT_INIT_ADDRESS macro in glibc - // as well as ELF_FUNCTION_PTR_IS_SPECIAL. We've not handled - // it here, please file a bug report if it affects you. - for (i = 0; i < elf_shnum(ehdr); i++) { - init_t *init_start, *init_end, *init; - int is_bss = FALSE; - SectionKind kind = getSectionKind_ELF(&shdr[i], &is_bss); - if (kind == SECTIONKIND_CODE_OR_RODATA - && 0 == memcmp(".init", sh_strtab + shdr[i].sh_name, 5)) { - init_t init_f = (init_t)(oc->sections[i].start); - init_f(argc, argv, envv); - } - - if (kind == SECTIONKIND_INIT_ARRAY) { - char *init_startC = oc->sections[i].start; - init_start = (init_t*)init_startC; - init_end = (init_t*)(init_startC + shdr[i].sh_size); - for (init = init_start; init < init_end; init++) { - (*init)(argc, argv, envv); - } - } - - // XXX could be more strict and assert that it's - // SECTIONKIND_RWDATA; but allowing RODATA seems harmless enough. - if ((kind == SECTIONKIND_RWDATA || kind == SECTIONKIND_CODE_OR_RODATA) - && 0 == memcmp(".ctors", sh_strtab + shdr[i].sh_name, 6)) { - char *init_startC = oc->sections[i].start; - init_start = (init_t*)init_startC; - init_end = (init_t*)(init_startC + shdr[i].sh_size); - // ctors run in reverse - for (init = init_end - 1; init >= init_start; init--) { - (*init)(argc, argv, envv); - } - } - } - - freeProgEnvv(envc, envv); - return 1; -} - -/* - * PowerPC & X86_64 ELF specifics - */ - -#if NEED_SYMBOL_EXTRAS - -static int ocAllocateSymbolExtras_ELF( ObjectCode *oc ) -{ - Elf_Ehdr *ehdr; - Elf_Shdr* shdr; - Elf_Word i, shnum; - - ehdr = (Elf_Ehdr *) oc->image; - shdr = (Elf_Shdr *) ( ((char *)oc->image) + ehdr->e_shoff ); - - shnum = elf_shnum(ehdr); - - for( i = 0; i < shnum; i++ ) - if( shdr[i].sh_type == SHT_SYMTAB ) - break; - - if( i == shnum ) - { - // Not having a symbol table is not in principle a problem. - // When an object file has no symbols then the 'strip' program - // typically will remove the symbol table entirely. - IF_DEBUG(linker, debugBelch( "The ELF file %s contains no symtab\n", - oc->archiveMemberName ? oc->archiveMemberName : oc->fileName )); - return 1; - } - - if( shdr[i].sh_entsize != sizeof( Elf_Sym ) ) - { - errorBelch( "The entry size (%d) of the symtab isn't %d\n", - (int) shdr[i].sh_entsize, (int) sizeof( Elf_Sym ) ); - - return 0; - } - - return ocAllocateSymbolExtras( oc, shdr[i].sh_size / sizeof( Elf_Sym ), 0 ); -} - -#endif /* NEED_SYMBOL_EXTRAS */ - -#endif /* ELF */ - -/* -------------------------------------------------------------------------- - * Mach-O specifics - * ------------------------------------------------------------------------*/ - diff --git a/rts/LinkerInternals.h b/rts/LinkerInternals.h index 3b6790b3e8..47e0375a2c 100644 --- a/rts/LinkerInternals.h +++ b/rts/LinkerInternals.h @@ -224,6 +224,18 @@ void addSection (Section *s, SectionKind kind, SectionAlloc alloc, HsBool ghciLookupSymbolInfo(HashTable *table, const SymbolName* key, RtsSymbolInfo **result); +int ghciInsertSymbolTable( + pathchar* obj_name, + HashTable *table, + const SymbolName* key, + SymbolAddr* data, + HsBool weak, + ObjectCode *owner); + +/* lock-free version of lookupSymbol */ +SymbolAddr* lookupSymbol_ (SymbolName* lbl); + +extern /*Str*/HashTable *symhash; /************************************************* diff --git a/rts/linker/Elf.c b/rts/linker/Elf.c new file mode 100644 index 0000000000..6b3e3ac3b3 --- /dev/null +++ b/rts/linker/Elf.c @@ -0,0 +1,1709 @@ +#include "Rts.h" + +#if defined(linux_HOST_OS) || defined(solaris2_HOST_OS) || defined(freebsd_HOST_OS) || defined(kfreebsdgnu_HOST_OS) || defined(dragonfly_HOST_OS) || defined(netbsd_HOST_OS) || defined(openbsd_HOST_OS) || defined(gnu_HOST_OS) + +#include "RtsUtils.h" +#include "RtsSymbolInfo.h" +#include "linker/Elf.h" +#include "linker/CacheFlush.h" +#include "linker/M32Alloc.h" +#include "linker/SymbolExtras.h" +#include "sm/OSMem.h" +#include "GetEnv.h" + +#include <stdlib.h> +#include <string.h> +#ifdef HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif +#ifdef HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif +#ifdef HAVE_FCNTL_H +#include <fcntl.h> +#endif + +/* on x86_64 we have a problem with relocating symbol references in + * code that was compiled without -fPIC. By default, the small memory + * model is used, which assumes that symbol references can fit in a + * 32-bit slot. The system dynamic linker makes this work for + * references to shared libraries by either (a) allocating a jump + * table slot for code references, or (b) moving the symbol at load + * time (and copying its contents, if necessary) for data references. + * + * We unfortunately can't tell whether symbol references are to code + * or data. So for now we assume they are code (the vast majority + * are), and allocate jump-table slots. Unfortunately this will + * SILENTLY generate crashing code for data references. This hack is + * enabled by X86_64_ELF_NONPIC_HACK. + * + * One workaround is to use shared Haskell libraries. This is + * coming. Another workaround is to keep the static libraries but + * compile them with -fPIC, because that will generate PIC references + * to data which can be relocated. The PIC code is still too green to + * do this systematically, though. + * + * See bug #781 + * See thread http://www.haskell.org/pipermail/cvs-ghc/2007-September/038458.html + * + * Naming Scheme for Symbol Macros + * + * SymI_*: symbol is internal to the RTS. It resides in an object + * file/library that is statically. + * SymE_*: symbol is external to the RTS library. It might be linked + * dynamically. + * + * Sym*_HasProto : the symbol prototype is imported in an include file + * or defined explicitly + * Sym*_NeedsProto: the symbol is undefined and we add a dummy + * default proto extern void sym(void); + */ +#define X86_64_ELF_NONPIC_HACK 1 + +#define FALSE 0 +#define TRUE 1 + +#if defined(sparc_HOST_ARCH) +# define ELF_TARGET_SPARC /* Used inside <elf.h> */ +#elif defined(i386_HOST_ARCH) +# define ELF_TARGET_386 /* Used inside <elf.h> */ +#elif defined(x86_64_HOST_ARCH) +# define ELF_TARGET_X64_64 +# define ELF_64BIT +# define ELF_TARGET_AMD64 /* Used inside <elf.h> on Solaris 11 */ +#elif defined(powerpc64_HOST_ARCH) || defined(powerpc64le_HOST_ARCH) +# define ELF_64BIT +#elif defined(ia64_HOST_ARCH) +# define ELF_64BIT +#elif defined(aarch64_HOST_ARCH) +# define ELF_64BIT +#endif + +#if !defined(openbsd_HOST_OS) +# include <elf.h> +#else +/* openbsd elf has things in different places, with diff names */ +# include <elf_abi.h> +# include <machine/reloc.h> +# define R_386_32 RELOC_32 +# define R_386_PC32 RELOC_PC32 +#endif + +/* If elf.h doesn't define it */ +# ifndef R_X86_64_PC64 +# define R_X86_64_PC64 24 +# endif + +/* + * Workaround for libc implementations (e.g. eglibc) with incomplete + * relocation lists + */ +#ifndef R_ARM_THM_CALL +# define R_ARM_THM_CALL 10 +#endif +#ifndef R_ARM_CALL +# define R_ARM_CALL 28 +#endif +#ifndef R_ARM_JUMP24 +# define R_ARM_JUMP24 29 +#endif +#ifndef R_ARM_THM_JUMP24 +# define R_ARM_THM_JUMP24 30 +#endif +#ifndef R_ARM_TARGET1 +# define R_ARM_TARGET1 38 +#endif +#ifndef R_ARM_MOVW_ABS_NC +# define R_ARM_MOVW_ABS_NC 43 +#endif +#ifndef R_ARM_MOVT_ABS +# define R_ARM_MOVT_ABS 44 +#endif +#ifndef R_ARM_THM_MOVW_ABS_NC +# define R_ARM_THM_MOVW_ABS_NC 47 +#endif +#ifndef R_ARM_THM_MOVT_ABS +# define R_ARM_THM_MOVT_ABS 48 +#endif +#ifndef R_ARM_THM_JUMP11 +# define R_ARM_THM_JUMP11 102 +#endif +#ifndef R_ARM_THM_JUMP8 +# define R_ARM_THM_JUMP8 103 +#endif + +/* + * Define a set of types which can be used for both ELF32 and ELF64 + */ + +#ifdef ELF_64BIT +#define ELFCLASS ELFCLASS64 +#define Elf_Addr Elf64_Addr +#define Elf_Word Elf64_Word +#define Elf_Sword Elf64_Sword +#define Elf_Half Elf64_Half +#define Elf_Ehdr Elf64_Ehdr +#define Elf_Phdr Elf64_Phdr +#define Elf_Shdr Elf64_Shdr +#define Elf_Sym Elf64_Sym +#define Elf_Rel Elf64_Rel +#define Elf_Rela Elf64_Rela +#ifndef ELF_ST_TYPE +#define ELF_ST_TYPE ELF64_ST_TYPE +#endif +#ifndef ELF_ST_BIND +#define ELF_ST_BIND ELF64_ST_BIND +#endif +#ifndef ELF_R_TYPE +#define ELF_R_TYPE ELF64_R_TYPE +#endif +#ifndef ELF_R_SYM +#define ELF_R_SYM ELF64_R_SYM +#endif +#else +#define ELFCLASS ELFCLASS32 +#define Elf_Addr Elf32_Addr +#define Elf_Word Elf32_Word +#define Elf_Sword Elf32_Sword +#define Elf_Half Elf32_Half +#define Elf_Ehdr Elf32_Ehdr +#define Elf_Phdr Elf32_Phdr +#define Elf_Shdr Elf32_Shdr +#define Elf_Sym Elf32_Sym +#define Elf_Rel Elf32_Rel +#define Elf_Rela Elf32_Rela +#ifndef ELF_ST_TYPE +#define ELF_ST_TYPE ELF32_ST_TYPE +#endif +#ifndef ELF_ST_BIND +#define ELF_ST_BIND ELF32_ST_BIND +#endif +#ifndef ELF_R_TYPE +#define ELF_R_TYPE ELF32_R_TYPE +#endif +#ifndef ELF_R_SYM +#define ELF_R_SYM ELF32_R_SYM +#endif +#endif + + +/* + * Functions to allocate entries in dynamic sections. Currently we simply + * preallocate a large number, and we don't check if a entry for the given + * target already exists (a linear search is too slow). Ideally these + * entries would be associated with symbols. + */ + +/* These sizes sufficient to load HSbase + HShaskell98 + a few modules */ +#define GOT_SIZE 0x20000 +#define FUNCTION_TABLE_SIZE 0x10000 +#define PLT_SIZE 0x08000 + +#ifdef ELF_NEED_GOT +static Elf_Addr got[GOT_SIZE]; +static unsigned int gotIndex; +static Elf_Addr gp_val = (Elf_Addr)got; + +static Elf_Addr +allocateGOTEntry(Elf_Addr target) +{ + Elf_Addr *entry; + + if (gotIndex >= GOT_SIZE) + barf("Global offset table overflow"); + + entry = &got[gotIndex++]; + *entry = target; + return (Elf_Addr)entry; +} +#endif + +#ifdef ELF_FUNCTION_DESC +typedef struct { + Elf_Addr ip; + Elf_Addr gp; +} FunctionDesc; + +static FunctionDesc functionTable[FUNCTION_TABLE_SIZE]; +static unsigned int functionTableIndex; + +static Elf_Addr +allocateFunctionDesc(Elf_Addr target) +{ + FunctionDesc *entry; + + if (functionTableIndex >= FUNCTION_TABLE_SIZE) + barf("Function table overflow"); + + entry = &functionTable[functionTableIndex++]; + entry->ip = target; + entry->gp = (Elf_Addr)gp_val; + return (Elf_Addr)entry; +} + +static Elf_Addr +copyFunctionDesc(Elf_Addr target) +{ + FunctionDesc *olddesc = (FunctionDesc *)target; + FunctionDesc *newdesc; + + newdesc = (FunctionDesc *)allocateFunctionDesc(olddesc->ip); + newdesc->gp = olddesc->gp; + return (Elf_Addr)newdesc; +} +#endif + +#ifdef ELF_NEED_PLT + +typedef struct { + unsigned char code[sizeof(plt_code)]; +} PLTEntry; + +static Elf_Addr +allocatePLTEntry(Elf_Addr target, ObjectCode *oc) +{ + PLTEntry *plt = (PLTEntry *)oc->plt; + PLTEntry *entry; + + if (oc->pltIndex >= PLT_SIZE) + barf("Procedure table overflow"); + + entry = &plt[oc->pltIndex++]; + memcpy(entry->code, plt_code, sizeof(entry->code)); + PLT_RELOC(entry->code, target); + return (Elf_Addr)entry; +} + +static unsigned int +PLTSize(void) +{ + return (PLT_SIZE * sizeof(PLTEntry)); +} +#endif + +/* + + Note [Many ELF Sections] + + The normal section number fields in ELF are limited to 16 bits, which runs + out of bits when you try to cram in more sections than that. + + To solve this, the fields e_shnum and e_shstrndx in the ELF header have an + escape value (different for each case), and the actual section number is + stashed into unused fields in the first section header. + + For symbols, there seems to have been no place in the actual symbol table + for the extra bits, so the indexes have been moved into an auxilliary + section instead. + For symbols in sections beyond 0xff00, the symbol's st_shndx will be an + escape value (SHN_XINDEX), and the actual 32-bit section number for symbol N + is stored at index N in the SHT_SYMTAB_SHNDX table. + + These extensions seem to be undocumented in version 4.1 of the ABI and only + appear in the drafts for the "next" version: + https://refspecs.linuxfoundation.org/elf/gabi4+/contents.html + +*/ + +static Elf_Word elf_shnum(Elf_Ehdr* ehdr) +{ + Elf_Shdr* shdr = (Elf_Shdr*) ((char*)ehdr + ehdr->e_shoff); + Elf_Half shnum = ehdr->e_shnum; + return shnum != SHN_UNDEF ? shnum : shdr[0].sh_size; +} + +static Elf_Word elf_shstrndx(Elf_Ehdr* ehdr) +{ + Elf_Shdr* shdr = (Elf_Shdr*) ((char*)ehdr + ehdr->e_shoff); + Elf_Half shstrndx = ehdr->e_shstrndx; +#if defined(SHN_XINDEX) + return shstrndx != SHN_XINDEX ? shstrndx : shdr[0].sh_link; +#else + // some OSes do not support SHN_XINDEX yet, let's revert to + // old way + return shstrndx; +#endif +} + +#if defined(SHN_XINDEX) +static Elf_Word* +get_shndx_table(Elf_Ehdr* ehdr) +{ + Elf_Word i; + char* ehdrC = (char*)ehdr; + Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); + const Elf_Word shnum = elf_shnum(ehdr); + + for (i = 0; i < shnum; i++) { + if (shdr[i].sh_type == SHT_SYMTAB_SHNDX) { + return (Elf32_Word*)(ehdrC + shdr[i].sh_offset); + } + } + return NULL; +} +#endif + +/* + * Generic ELF functions + */ + +int +ocVerifyImage_ELF ( ObjectCode* oc ) +{ + Elf_Shdr* shdr; + Elf_Sym* stab; + int j, nent, nstrtab, nsymtabs; + Elf_Word i, shnum, shstrndx; + char* sh_strtab; + + char* ehdrC = (char*)(oc->image); + Elf_Ehdr* ehdr = (Elf_Ehdr*)ehdrC; + + if (ehdr->e_ident[EI_MAG0] != ELFMAG0 || + ehdr->e_ident[EI_MAG1] != ELFMAG1 || + ehdr->e_ident[EI_MAG2] != ELFMAG2 || + ehdr->e_ident[EI_MAG3] != ELFMAG3) { + errorBelch("%s: not an ELF object", oc->fileName); + return 0; + } + + if (ehdr->e_ident[EI_CLASS] != ELFCLASS) { + errorBelch("%s: unsupported ELF format", oc->fileName); + return 0; + } + + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) { + IF_DEBUG(linker,debugBelch( "Is little-endian\n" )); + } else + if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) { + IF_DEBUG(linker,debugBelch( "Is big-endian\n" )); + } else { + errorBelch("%s: unknown endiannness", oc->fileName); + return 0; + } + + if (ehdr->e_type != ET_REL) { + errorBelch("%s: not a relocatable object (.o) file", oc->fileName); + return 0; + } + IF_DEBUG(linker, debugBelch( "Is a relocatable object (.o) file\n" )); + + IF_DEBUG(linker,debugBelch( "Architecture is " )); + switch (ehdr->e_machine) { +#ifdef EM_ARM + case EM_ARM: IF_DEBUG(linker,debugBelch( "arm" )); break; +#endif + case EM_386: IF_DEBUG(linker,debugBelch( "x86" )); break; +#ifdef EM_SPARC32PLUS + case EM_SPARC32PLUS: +#endif + case EM_SPARC: IF_DEBUG(linker,debugBelch( "sparc" )); break; +#ifdef EM_IA_64 + case EM_IA_64: IF_DEBUG(linker,debugBelch( "ia64" )); break; +#endif + case EM_PPC: IF_DEBUG(linker,debugBelch( "powerpc32" )); break; +#ifdef EM_X86_64 + case EM_X86_64: IF_DEBUG(linker,debugBelch( "x86_64" )); break; +#elif defined(EM_AMD64) + case EM_AMD64: IF_DEBUG(linker,debugBelch( "amd64" )); break; +#endif + default: IF_DEBUG(linker,debugBelch( "unknown" )); + errorBelch("%s: unknown architecture (e_machine == %d)" + , oc->fileName, ehdr->e_machine); + return 0; + } + + shnum = elf_shnum(ehdr); + IF_DEBUG(linker,debugBelch( + "\nSection header table: start %ld, n_entries %d, ent_size %d\n", + (long)ehdr->e_shoff, shnum, ehdr->e_shentsize )); + + ASSERT(ehdr->e_shentsize == sizeof(Elf_Shdr)); + + shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); + + shstrndx = elf_shstrndx(ehdr); + if (shstrndx == SHN_UNDEF) { + errorBelch("%s: no section header string table", oc->fileName); + return 0; + } else { + IF_DEBUG(linker,debugBelch( "Section header string table is section %d\n", + shstrndx)); + sh_strtab = ehdrC + shdr[shstrndx].sh_offset; + } + + for (i = 0; i < shnum; i++) { + IF_DEBUG(linker,debugBelch("%2d: ", i )); + IF_DEBUG(linker,debugBelch("type=%2d ", (int)shdr[i].sh_type )); + IF_DEBUG(linker,debugBelch("size=%4d ", (int)shdr[i].sh_size )); + IF_DEBUG(linker,debugBelch("offs=%4d ", (int)shdr[i].sh_offset )); + IF_DEBUG(linker,debugBelch(" (%p .. %p) ", + ehdrC + shdr[i].sh_offset, + ehdrC + shdr[i].sh_offset + shdr[i].sh_size - 1)); + +#define SECTION_INDEX_VALID(ndx) (ndx > SHN_UNDEF && ndx < shnum) + + switch (shdr[i].sh_type) { + + case SHT_REL: + case SHT_RELA: + IF_DEBUG(linker,debugBelch( shdr[i].sh_type == SHT_REL ? "Rel " : "RelA ")); + + if (!SECTION_INDEX_VALID(shdr[i].sh_link)) { + if (shdr[i].sh_link == SHN_UNDEF) + errorBelch("\n%s: relocation section #%d has no symbol table\n" + "This object file has probably been fully striped. " + "Such files cannot be linked.\n", + oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, i); + else + errorBelch("\n%s: relocation section #%d has an invalid link field (%d)\n", + oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, + i, shdr[i].sh_link); + return 0; + } + if (shdr[shdr[i].sh_link].sh_type != SHT_SYMTAB) { + errorBelch("\n%s: relocation section #%d does not link to a symbol table\n", + oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, i); + return 0; + } + if (!SECTION_INDEX_VALID(shdr[i].sh_info)) { + errorBelch("\n%s: relocation section #%d has an invalid info field (%d)\n", + oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, + i, shdr[i].sh_info); + return 0; + } + + break; + case SHT_SYMTAB: + IF_DEBUG(linker,debugBelch("Sym ")); + + if (!SECTION_INDEX_VALID(shdr[i].sh_link)) { + errorBelch("\n%s: symbol table section #%d has an invalid link field (%d)\n", + oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, + i, shdr[i].sh_link); + return 0; + } + if (shdr[shdr[i].sh_link].sh_type != SHT_STRTAB) { + errorBelch("\n%s: symbol table section #%d does not link to a string table\n", + oc->archiveMemberName ? oc->archiveMemberName : oc->fileName, i); + + return 0; + } + break; + case SHT_STRTAB: IF_DEBUG(linker,debugBelch("Str ")); break; + default: IF_DEBUG(linker,debugBelch(" ")); break; + } + if (sh_strtab) { + IF_DEBUG(linker,debugBelch("sname=%s\n", sh_strtab + shdr[i].sh_name )); + } + } + + IF_DEBUG(linker,debugBelch( "\nString tables\n" )); + nstrtab = 0; + for (i = 0; i < shnum; i++) { + if (shdr[i].sh_type == SHT_STRTAB + /* Ignore the section header's string table. */ + && i != shstrndx + /* Ignore string tables named .stabstr, as they contain + debugging info. */ + && 0 != memcmp(".stabstr", sh_strtab + shdr[i].sh_name, 8) + ) { + IF_DEBUG(linker,debugBelch(" section %d is a normal string table\n", i )); + nstrtab++; + } + } + if (nstrtab == 0) { + IF_DEBUG(linker,debugBelch(" no normal string tables (potentially, but not necessarily a problem)\n")); + } +#if defined(SHN_XINDEX) + Elf_Word* shndxTable = get_shndx_table(ehdr); +#endif + nsymtabs = 0; + IF_DEBUG(linker,debugBelch( "Symbol tables\n" )); + for (i = 0; i < shnum; i++) { + if (shdr[i].sh_type != SHT_SYMTAB) continue; + IF_DEBUG(linker,debugBelch( "section %d is a symbol table\n", i )); + nsymtabs++; + stab = (Elf_Sym*) (ehdrC + shdr[i].sh_offset); + nent = shdr[i].sh_size / sizeof(Elf_Sym); + IF_DEBUG(linker,debugBelch( " number of entries is apparently %d (%ld rem)\n", + nent, + (long)shdr[i].sh_size % sizeof(Elf_Sym) + )); + if (0 != shdr[i].sh_size % sizeof(Elf_Sym)) { + errorBelch("%s: non-integral number of symbol table entries", oc->fileName); + return 0; + } + for (j = 0; j < nent; j++) { + Elf_Word secno = stab[j].st_shndx; +#if defined(SHN_XINDEX) + /* See Note [Many ELF Sections] */ + if (secno == SHN_XINDEX) { + ASSERT(shndxTable); + secno = shndxTable[j]; + } +#endif + IF_DEBUG(linker,debugBelch(" %2d ", j )); + IF_DEBUG(linker,debugBelch(" sec=%-5d size=%-3d val=%5p ", + (int)secno, + (int)stab[j].st_size, + (char*)stab[j].st_value )); + + IF_DEBUG(linker,debugBelch("type=" )); + switch (ELF_ST_TYPE(stab[j].st_info)) { + case STT_NOTYPE: IF_DEBUG(linker,debugBelch("notype " )); break; + case STT_OBJECT: IF_DEBUG(linker,debugBelch("object " )); break; + case STT_FUNC : IF_DEBUG(linker,debugBelch("func " )); break; + case STT_SECTION: IF_DEBUG(linker,debugBelch("section" )); break; + case STT_FILE: IF_DEBUG(linker,debugBelch("file " )); break; + default: IF_DEBUG(linker,debugBelch("? " )); break; + } + IF_DEBUG(linker,debugBelch(" " )); + + IF_DEBUG(linker,debugBelch("bind=" )); + switch (ELF_ST_BIND(stab[j].st_info)) { + case STB_LOCAL : IF_DEBUG(linker,debugBelch("local " )); break; + case STB_GLOBAL: IF_DEBUG(linker,debugBelch("global" )); break; + case STB_WEAK : IF_DEBUG(linker,debugBelch("weak " )); break; + default: IF_DEBUG(linker,debugBelch("? " )); break; + } + IF_DEBUG(linker,debugBelch(" " )); + + IF_DEBUG(linker,debugBelch("other=%2x ", stab[j].st_other )); + IF_DEBUG(linker,debugBelch("name=%s [%x]\n", + ehdrC + shdr[shdr[i].sh_link].sh_offset + + stab[j].st_name, stab[j].st_name )); + } + } + + if (nsymtabs == 0) { + // Not having a symbol table is not in principle a problem. + // When an object file has no symbols then the 'strip' program + // typically will remove the symbol table entirely. + IF_DEBUG(linker,debugBelch(" no symbol tables (potentially, but not necessarily a problem)\n")); + } + + return 1; +} + +/* Figure out what kind of section it is. Logic derived from + Figure 1.14 ("Special Sections") of the ELF document + ("Portable Formats Specification, Version 1.1"). */ +static int getSectionKind_ELF( Elf_Shdr *hdr, int *is_bss ) +{ + *is_bss = FALSE; + + if (hdr->sh_type == SHT_PROGBITS + && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_EXECINSTR)) { + /* .text-style section */ + return SECTIONKIND_CODE_OR_RODATA; + } + + if (hdr->sh_type == SHT_PROGBITS + && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_WRITE)) { + /* .data-style section */ + return SECTIONKIND_RWDATA; + } + + if (hdr->sh_type == SHT_PROGBITS + && (hdr->sh_flags & SHF_ALLOC) && !(hdr->sh_flags & SHF_WRITE)) { + /* .rodata-style section */ + return SECTIONKIND_CODE_OR_RODATA; + } +#ifndef openbsd_HOST_OS + if (hdr->sh_type == SHT_INIT_ARRAY + && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_WRITE)) { + /* .init_array section */ + return SECTIONKIND_INIT_ARRAY; + } +#endif /* not OpenBSD */ + if (hdr->sh_type == SHT_NOBITS + && (hdr->sh_flags & SHF_ALLOC) && (hdr->sh_flags & SHF_WRITE)) { + /* .bss-style section */ + *is_bss = TRUE; + return SECTIONKIND_RWDATA; + } + + return SECTIONKIND_OTHER; +} + +static void * +mapObjectFileSection (int fd, Elf_Word offset, Elf_Word size, + void **mapped_start, StgWord *mapped_size, + StgWord *mapped_offset) +{ + void *p; + size_t pageOffset, pageSize; + + pageOffset = roundDownToPage(offset); + pageSize = roundUpToPage(offset-pageOffset+size); + p = mmapForLinker(pageSize, 0, fd, pageOffset); + if (p == NULL) return NULL; + *mapped_size = pageSize; + *mapped_offset = pageOffset; + *mapped_start = p; + return (void*)((StgWord)p + offset - pageOffset); +} + +int +ocGetNames_ELF ( ObjectCode* oc ) +{ + Elf_Word i; + int j, nent, result, fd = -1; + Elf_Sym* stab; + + char* ehdrC = (char*)(oc->image); + Elf_Ehdr* ehdr = (Elf_Ehdr*)ehdrC; + char* strtab; + Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); + Section * sections; +#if defined(SHN_XINDEX) + Elf_Word* shndxTable = get_shndx_table(ehdr); +#endif + const Elf_Word shnum = elf_shnum(ehdr); + + ASSERT(symhash != NULL); + + sections = (Section*)stgCallocBytes(sizeof(Section), shnum, + "ocGetNames_ELF(sections)"); + oc->sections = sections; + oc->n_sections = shnum; + + + if (oc->imageMapped) { +#if defined(openbsd_HOST_OS) + fd = open(oc->fileName, O_RDONLY, S_IRUSR); +#else + fd = open(oc->fileName, O_RDONLY); +#endif + if (fd == -1) { + errorBelch("loadObj: can't open %" PATH_FMT, oc->fileName); + return 0; + } + } + + for (i = 0; i < shnum; i++) { + int is_bss = FALSE; + SectionKind kind = getSectionKind_ELF(&shdr[i], &is_bss); + SectionAlloc alloc = SECTION_NOMEM; + void *start = NULL, *mapped_start = NULL; + StgWord mapped_size = 0, mapped_offset = 0; + StgWord size = shdr[i].sh_size; + StgWord offset = shdr[i].sh_offset; + + if (is_bss && size > 0) { + /* This is a non-empty .bss section. Allocate zeroed space for + it, and set its .sh_offset field such that + ehdrC + .sh_offset == addr_of_zeroed_space. */ + alloc = SECTION_MALLOC; + start = stgCallocBytes(1, size, "ocGetNames_ELF(BSS)"); + mapped_start = start; + /* + debugBelch("BSS section at 0x%x, size %d\n", + zspace, shdr[i].sh_size); + */ + } + + else if (kind != SECTIONKIND_OTHER && size > 0) { + if (USE_CONTIGUOUS_MMAP) { + // already mapped. + start = oc->image + offset; + alloc = SECTION_NOMEM; + } + // use the m32 allocator if either the image is not mapped + // (i.e. we cannot map the secions separately), or if the section + // size is small. + else if (!oc->imageMapped || size < getPageSize() / 3) { + start = m32_alloc(size, 8); + if (start == NULL) goto fail; + memcpy(start, oc->image + offset, size); + alloc = SECTION_M32; + } else { + start = mapObjectFileSection(fd, offset, size, + &mapped_start, &mapped_size, + &mapped_offset); + if (start == NULL) goto fail; + alloc = SECTION_MMAP; + } + addProddableBlock(oc, start, size); + } + + addSection(§ions[i], kind, alloc, start, size, + mapped_offset, mapped_start, mapped_size); + + if (shdr[i].sh_type != SHT_SYMTAB) continue; + + /* copy stuff into this module's object symbol table */ + stab = (Elf_Sym*) (ehdrC + offset); + strtab = ehdrC + shdr[shdr[i].sh_link].sh_offset; + nent = shdr[i].sh_size / sizeof(Elf_Sym); + + oc->n_symbols = nent; + oc->symbols = stgCallocBytes(oc->n_symbols, sizeof(SymbolName*), + "ocGetNames_ELF(oc->symbols)"); + // Note calloc: if we fail partway through initializing symbols, we need + // to undo the additions to the symbol table so far. We know which ones + // have been added by whether the entry is NULL or not. + + //TODO: we ignore local symbols anyway right? So we can use the + // shdr[i].sh_info to get the index of the first non-local symbol + // ie we should use j = shdr[i].sh_info + for (j = 0; j < nent; j++) { + + char isLocal = FALSE; /* avoids uninit-var warning */ + HsBool isWeak = HS_BOOL_FALSE; + SymbolAddr* ad = NULL; + SymbolName* nm = strtab + stab[j].st_name; + unsigned short shndx = stab[j].st_shndx; + Elf_Word secno; + + /* See Note [Many ELF Sections] */ + /* Note that future checks for special SHN_* numbers should check the + * shndx variable, not the section number in secno. Sections with the + * real number in the SHN_LORESERVE..HIRESERVE range will have shndx + * SHN_XINDEX and a secno with one of the reserved values. */ + secno = shndx; +#if defined(SHN_XINDEX) + if (shndx == SHN_XINDEX) { + ASSERT(shndxTable); + secno = shndxTable[j]; + } +#endif + /* Figure out if we want to add it; if so, set ad to its + address. Otherwise leave ad == NULL. */ + + if (shndx == SHN_COMMON) { + isLocal = FALSE; + ad = stgCallocBytes(1, stab[j].st_size, "ocGetNames_ELF(COMMON)"); + /* + debugBelch("COMMON symbol, size %d name %s\n", + stab[j].st_size, nm); + */ + /* Pointless to do addProddableBlock() for this area, + since the linker should never poke around in it. */ + } + else + if ( ( ELF_ST_BIND(stab[j].st_info)==STB_GLOBAL + || ELF_ST_BIND(stab[j].st_info)==STB_LOCAL + || ELF_ST_BIND(stab[j].st_info)==STB_WEAK + ) + /* and not an undefined symbol */ + && shndx != SHN_UNDEF + /* and not in a "special section" */ + && (shndx < SHN_LORESERVE +#if defined(SHN_XINDEX) + || shndx == SHN_XINDEX +#endif + ) + && + /* and it's a not a section or string table or anything silly */ + ( ELF_ST_TYPE(stab[j].st_info)==STT_FUNC || + ELF_ST_TYPE(stab[j].st_info)==STT_OBJECT || + ELF_ST_TYPE(stab[j].st_info)==STT_NOTYPE + ) + ) { + /* Section 0 is the undefined section, hence > and not >=. */ + ASSERT(secno > 0 && secno < shnum); + /* + if (shdr[secno].sh_type == SHT_NOBITS) { + debugBelch(" BSS symbol, size %d off %d name %s\n", + stab[j].st_size, stab[j].st_value, nm); + } + */ + ad = (SymbolAddr*)((intptr_t)sections[secno].start + + (intptr_t)stab[j].st_value); + if (ELF_ST_BIND(stab[j].st_info)==STB_LOCAL) { + isLocal = TRUE; + isWeak = FALSE; + } else { /* STB_GLOBAL or STB_WEAK */ +#ifdef ELF_FUNCTION_DESC + /* dlsym() and the initialisation table both give us function + * descriptors, so to be consistent we store function descriptors + * in the symbol table */ + if (ELF_ST_TYPE(stab[j].st_info) == STT_FUNC) + ad = (SymbolAddr*)allocateFunctionDesc((Elf_Addr)ad); +#endif + IF_DEBUG(linker,debugBelch( "addOTabName(GLOB): %10p %s %s\n", + ad, oc->fileName, nm )); + isLocal = FALSE; + isWeak = (ELF_ST_BIND(stab[j].st_info)==STB_WEAK); + } + } + + /* And the decision is ... */ + + oc->symbols[j] = nm; + + if (ad != NULL) { + ASSERT(nm != NULL); + /* Acquire! */ + if (isLocal) { + /* Ignore entirely. */ + oc->symbols[j] = NULL; + } else { + + if (isWeak == HS_BOOL_TRUE) { + setWeakSymbol(oc, nm); + } + + if (! ghciInsertSymbolTable(oc->fileName, symhash, + nm, ad, isWeak, oc)) { + goto fail; + } + } + } else { + /* Skip. */ + IF_DEBUG(linker,debugBelch( "skipping `%s'\n", + nm )); + + /* We're skipping the symbol, but if we ever load this + object file we'll want to skip it then too. */ + oc->symbols[j] = NULL; + + /* + debugBelch( + "skipping bind = %d, type = %d, secno = %d `%s'\n", + (int)ELF_ST_BIND(stab[j].st_info), + (int)ELF_ST_TYPE(stab[j].st_info), + (int)secno, + nm + ); + */ + } + + } + } + + result = 1; + goto end; + +fail: + result = 0; + goto end; + +end: + if (fd >= 0) close(fd); + return result; +} + +#ifdef arm_HOST_ARCH +// TODO: These likely belong in a library somewhere + +// Signed extend a number to a 32-bit int. +static inline StgInt32 sign_extend32(uint32_t bits, StgWord32 x) { + return ((StgInt32) (x << (32 - bits))) >> (32 - bits); +} + +// Does the given signed integer fit into the given bit width? +static inline StgBool is_int(uint32_t bits, StgInt32 x) { + return bits > 32 || (-(1 << (bits-1)) <= x + && x < (1 << (bits-1))); +} +#endif + +/* Do ELF relocations which lack an explicit addend. All x86-linux + and arm-linux relocations appear to be of this form. */ +static int +do_Elf_Rel_relocations ( ObjectCode* oc, char* ehdrC, + Elf_Shdr* shdr, int shnum ) +{ + int j; + SymbolName* symbol; + Elf_Word* targ; + Elf_Rel* rtab = (Elf_Rel*) (ehdrC + shdr[shnum].sh_offset); + Elf_Sym* stab; + char* strtab; + int nent = shdr[shnum].sh_size / sizeof(Elf_Rel); + int target_shndx = shdr[shnum].sh_info; + int symtab_shndx = shdr[shnum].sh_link; + int strtab_shndx = shdr[symtab_shndx].sh_link; +#if defined(SHN_XINDEX) + Elf_Word* shndx_table = get_shndx_table((Elf_Ehdr*)ehdrC); +#endif + + stab = (Elf_Sym*) (ehdrC + shdr[ symtab_shndx ].sh_offset); + strtab= (char*) (ehdrC + shdr[ strtab_shndx ].sh_offset); + targ = (Elf_Word*)oc->sections[target_shndx].start; + IF_DEBUG(linker,debugBelch( "relocations for section %d using symtab %d and strtab %d\n", + target_shndx, symtab_shndx, strtab_shndx )); + + /* Skip sections that we're not interested in. */ + if (oc->sections[target_shndx].kind == SECTIONKIND_OTHER) { + IF_DEBUG(linker,debugBelch( "skipping (target section not loaded)")); + return 1; + } + + for (j = 0; j < nent; j++) { + Elf_Addr offset = rtab[j].r_offset; + Elf_Addr info = rtab[j].r_info; + + Elf_Addr P = ((Elf_Addr)targ) + offset; + Elf_Word* pP = (Elf_Word*)P; +#if defined(i386_HOST_ARCH) || defined(DEBUG) + Elf_Addr A = *pP; +#endif + Elf_Addr S; + void* S_tmp; +#ifdef i386_HOST_ARCH + Elf_Addr value; +#endif +#ifdef arm_HOST_ARCH + int is_target_thm=0, T=0; +#endif + + IF_DEBUG(linker,debugBelch( "Rel entry %3d is raw(%6p %6p): ", + j, (void*)offset, (void*)info )); + if (!info) { + IF_DEBUG(linker,debugBelch( " ZERO" )); + S = 0; + } else { + Elf_Sym sym = stab[ELF_R_SYM(info)]; + /* First see if it is a local symbol. */ + if (ELF_ST_BIND(sym.st_info) == STB_LOCAL) { + /* Yes, so we can get the address directly from the ELF symbol + table. */ + symbol = sym.st_name==0 ? "(noname)" : strtab+sym.st_name; + /* See Note [Many ELF Sections] */ + Elf_Word secno = sym.st_shndx; +#if defined(SHN_XINDEX) + if (secno == SHN_XINDEX) { + ASSERT(shndx_table); + secno = shndx_table[ELF_R_SYM(info)]; + } +#endif + S = (Elf_Addr)oc->sections[ secno ].start + + stab[ELF_R_SYM(info)].st_value; + } else { + symbol = strtab + sym.st_name; + S_tmp = lookupSymbol_( symbol ); + S = (Elf_Addr)S_tmp; + } + if (!S) { + errorBelch("%s: unknown symbol `%s'", oc->fileName, symbol); + return 0; + } + IF_DEBUG(linker,debugBelch( "`%s' resolves to %p\n", symbol, (void*)S )); + +#ifdef arm_HOST_ARCH + // Thumb instructions have bit 0 of symbol's st_value set + is_target_thm = S & 0x1; + + T = sym.st_info & STT_FUNC && is_target_thm; + + // Make sure we clear bit 0. Strictly speaking we should have done + // this to st_value above but I believe alignment requirements should + // ensure that no instructions start on an odd address + S &= ~1; +#endif + } + + int reloc_type = ELF_R_TYPE(info); + IF_DEBUG(linker,debugBelch( "Reloc: P = %p S = %p A = %p type=%d\n", + (void*)P, (void*)S, (void*)A, reloc_type )); + checkProddableBlock ( oc, pP, sizeof(Elf_Word) ); + +#ifdef i386_HOST_ARCH + value = S + A; +#endif + + switch (reloc_type) { +# ifdef i386_HOST_ARCH + case R_386_32: *pP = value; break; + case R_386_PC32: *pP = value - P; break; +# endif + +# ifdef arm_HOST_ARCH + case R_ARM_ABS32: + case R_ARM_TARGET1: // Specified by Linux ARM ABI to be equivalent to ABS32 + *(Elf32_Word *)P += S; + *(Elf32_Word *)P |= T; + break; + + case R_ARM_REL32: + *(Elf32_Word *)P += S; + *(Elf32_Word *)P |= T; + *(Elf32_Word *)P -= P; + break; + + case R_ARM_CALL: + case R_ARM_JUMP24: + { + // N.B. LLVM's LLD linker's relocation implement is a fantastic + // resource + StgWord32 *word = (StgWord32 *)P; + StgInt32 imm = (*word & ((1<<24)-1)) << 2; + + const StgBool is_blx = (*word & 0xf0000000) == 0xf0000000; + const StgWord32 hBit = is_blx ? ((*word >> 24) & 1) : 0; + imm |= hBit << 1; + + // Sign extend to 32 bits + // I would have thought this would be 24 bits but LLD uses 26 here. + // Hmm. + imm = sign_extend32(26, imm); + + StgWord32 result = ((S + imm) | T) - P; + + const StgBool overflow = !is_int(26, (StgInt32) result); + + // Handle overflow and Thumb interworking + const StgBool needs_veneer = (is_target_thm && ELF_R_TYPE(info) == R_ARM_JUMP24) || overflow; + if (needs_veneer) { + // Generate veneer + // The +8 below is to undo the PC-bias compensation done by the object producer + SymbolExtra *extra = makeArmSymbolExtra(oc, ELF_R_SYM(info), S+imm+8, 0, is_target_thm); + // The -8 below is to compensate for PC bias + result = (StgWord32) ((StgInt32) extra->jumpIsland - P - 8); + result &= ~1; // Clear thumb indicator bit + if (!is_int(26, (StgInt32) result)) { + errorBelch("Unable to fixup overflow'd R_ARM_CALL: jump island=%p, reloc=%p\n", + (void*) extra->jumpIsland, (void*) P); + return 0; + } + } + + // Update the branch target + const StgWord32 imm24 = (result & 0x03fffffc) >> 2; + *word = (*word & ~0x00ffffff) + | (imm24 & 0x00ffffff); + + // Change the relocated branch into a BLX if necessary + const StgBool switch_mode = is_target_thm && (reloc_type == R_ARM_CALL); + if (!needs_veneer && switch_mode) { + const StgWord32 hBit = (result & 0x2) >> 1; + // Change instruction to BLX + *word = (*word & ~0xFF000000) | ((0xfa | hBit) << 24); + IF_DEBUG(linker, debugBelch("Changed BL to BLX at %p\n", word)); + } + break; + } + + case R_ARM_MOVT_ABS: + case R_ARM_MOVW_ABS_NC: + { + StgWord32 *word = (StgWord32 *)P; + StgWord32 imm12 = *word & 0xfff; + StgWord32 imm4 = (*word >> 16) & 0xf; + StgInt32 offset = imm4 << 12 | imm12; + StgWord32 result = (S + offset) | T; + + if (reloc_type == R_ARM_MOVT_ABS) + result = (result & 0xffff0000) >> 16; + + StgWord32 result12 = result & 0xfff; + StgWord32 result4 = (result >> 12) & 0xf; + *word = (*word & ~0xf0fff) | (result4 << 16) | result12; + break; + } + + case R_ARM_THM_CALL: + case R_ARM_THM_JUMP24: + { + StgWord16 *upper = (StgWord16 *)P; + StgWord16 *lower = (StgWord16 *)(P + 2); + + int overflow; + int to_thm = (*lower >> 12) & 1; + int sign = (*upper >> 10) & 1; + int j1, j2, i1, i2; + + // Decode immediate value + j1 = (*lower >> 13) & 1; i1 = ~(j1 ^ sign) & 1; + j2 = (*lower >> 11) & 1; i2 = ~(j2 ^ sign) & 1; + StgInt32 imm = (sign << 24) + | (i1 << 23) + | (i2 << 22) + | ((*upper & 0x03ff) << 12) + | ((*lower & 0x07ff) << 1); + + // Sign extend 25 to 32 bits + if (imm & 0x01000000) + imm -= 0x02000000; + + offset = ((imm + S) | T) - P; + overflow = offset <= (StgWord32)0xff000000 || offset >= (StgWord32)0x01000000; + + if ((!is_target_thm && ELF_R_TYPE(info) == R_ARM_THM_JUMP24) || overflow) { + // Generate veneer + SymbolExtra *extra = makeArmSymbolExtra(oc, ELF_R_SYM(info), S+imm+4, 1, is_target_thm); + offset = (StgWord32) &extra->jumpIsland - P - 4; + sign = offset >> 31; + to_thm = 1; + } else if (!is_target_thm && ELF_R_TYPE(info) == R_ARM_THM_CALL) { + offset &= ~0x3; + to_thm = 0; + } + + // Reencode instruction + i1 = ~(offset >> 23) & 1; j1 = sign ^ i1; + i2 = ~(offset >> 22) & 1; j2 = sign ^ i2; + *upper = ( (*upper & 0xf800) + | (sign << 10) + | ((offset >> 12) & 0x03ff) ); + *lower = ( (*lower & 0xd000) + | (j1 << 13) + | (to_thm << 12) + | (j2 << 11) + | ((offset >> 1) & 0x07ff) ); + break; + } + + case R_ARM_THM_MOVT_ABS: + case R_ARM_THM_MOVW_ABS_NC: + { + StgWord16 *upper = (StgWord16 *)P; + StgWord16 *lower = (StgWord16 *)(P + 2); + StgInt32 offset = ((*upper & 0x000f) << 12) + | ((*upper & 0x0400) << 1) + | ((*lower & 0x7000) >> 4) + | (*lower & 0x00ff); + + offset = (offset ^ 0x8000) - 0x8000; // Sign extend + offset += S; + if (ELF_R_TYPE(info) == R_ARM_THM_MOVW_ABS_NC) + offset |= T; + else if (ELF_R_TYPE(info) == R_ARM_THM_MOVT_ABS) + offset >>= 16; + + *upper = ( (*upper & 0xfbf0) + | ((offset & 0xf000) >> 12) + | ((offset & 0x0800) >> 1) ); + *lower = ( (*lower & 0x8f00) + | ((offset & 0x0700) << 4) + | (offset & 0x00ff) ); + break; + } + + case R_ARM_THM_JUMP8: + { + StgWord16 *word = (StgWord16 *)P; + StgWord offset = *word & 0x01fe; + offset += S - P; + if (!is_target_thm) { + errorBelch("%s: Thumb to ARM transition with JUMP8 relocation not supported\n", + oc->fileName); + return 0; + } + + *word = (*word & ~0x01fe) + | (offset & 0x01fe); + break; + } + + case R_ARM_THM_JUMP11: + { + StgWord16 *word = (StgWord16 *)P; + StgWord offset = *word & 0x0ffe; + offset += S - P; + if (!is_target_thm) { + errorBelch("%s: Thumb to ARM transition with JUMP11 relocation not supported\n", + oc->fileName); + return 0; + } + + *word = (*word & ~0x0ffe) + | (offset & 0x0ffe); + break; + } + +# endif // arm_HOST_ARCH + + default: + errorBelch("%s: unhandled ELF relocation(Rel) type %" FMT_Word "\n", + oc->fileName, (W_)ELF_R_TYPE(info)); + return 0; + } + + } + return 1; +} + +/* Do ELF relocations for which explicit addends are supplied. + sparc-solaris relocations appear to be of this form. */ +static int +do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC, + Elf_Shdr* shdr, int shnum ) +{ + int j; + SymbolName* symbol = NULL; + Elf_Rela* rtab = (Elf_Rela*) (ehdrC + shdr[shnum].sh_offset); + Elf_Sym* stab; + char* strtab; + int nent = shdr[shnum].sh_size / sizeof(Elf_Rela); + int symtab_shndx = shdr[shnum].sh_link; + int strtab_shndx = shdr[symtab_shndx].sh_link; + int target_shndx = shdr[shnum].sh_info; +#if defined(SHN_XINDEX) + Elf_Word* shndx_table = get_shndx_table((Elf_Ehdr*)ehdrC); +#endif +#if defined(DEBUG) || defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) + /* This #ifdef only serves to avoid unused-var warnings. */ + Elf_Addr targ = (Elf_Addr) oc->sections[target_shndx].start; +#endif + + stab = (Elf_Sym*) (ehdrC + shdr[ symtab_shndx ].sh_offset); + strtab= (char*) (ehdrC + shdr[ strtab_shndx ].sh_offset); + + IF_DEBUG(linker,debugBelch( "relocations for section %d using symtab %d\n", + target_shndx, symtab_shndx )); + + /* Skip sections that we're not interested in. */ + if (oc->sections[target_shndx].kind == SECTIONKIND_OTHER) { + IF_DEBUG(linker,debugBelch( "skipping (target section not loaded)")); + return 1; + } + + for (j = 0; j < nent; j++) { +#if defined(DEBUG) || defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) + /* This #ifdef only serves to avoid unused-var warnings. */ + Elf_Addr offset = rtab[j].r_offset; + Elf_Addr P = targ + offset; + Elf_Addr A = rtab[j].r_addend; +#endif +#if defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) + Elf_Addr value; +#endif + Elf_Addr info = rtab[j].r_info; + Elf_Addr S; + void* S_tmp; +# if defined(sparc_HOST_ARCH) + Elf_Word* pP = (Elf_Word*)P; + Elf_Word w1, w2; +# elif defined(powerpc_HOST_ARCH) + Elf_Sword delta; +# endif + + IF_DEBUG(linker,debugBelch( "Rel entry %3d is raw(%6p %6p %6p) ", + j, (void*)offset, (void*)info, + (void*)A )); + if (!info) { + IF_DEBUG(linker,debugBelch( " ZERO" )); + S = 0; + } else { + Elf_Sym sym = stab[ELF_R_SYM(info)]; + /* First see if it is a local symbol. */ + if (ELF_ST_BIND(sym.st_info) == STB_LOCAL) { + /* Yes, so we can get the address directly from the ELF symbol + table. */ + symbol = sym.st_name==0 ? "(noname)" : strtab+sym.st_name; + /* See Note [Many ELF Sections] */ + Elf_Word secno = sym.st_shndx; +#if defined(SHN_XINDEX) + if (secno == SHN_XINDEX) { + secno = shndx_table[ELF_R_SYM(info)]; + } +#endif + S = (Elf_Addr)oc->sections[secno].start + + stab[ELF_R_SYM(info)].st_value; +#ifdef ELF_FUNCTION_DESC + /* Make a function descriptor for this function */ + if (S && ELF_ST_TYPE(sym.st_info) == STT_FUNC) { + S = allocateFunctionDesc(S + A); + A = 0; + } +#endif + } else { + /* No, so look up the name in our global table. */ + symbol = strtab + sym.st_name; + S_tmp = lookupSymbol_( symbol ); + S = (Elf_Addr)S_tmp; + +#ifdef ELF_FUNCTION_DESC + /* If a function, already a function descriptor - we would + have to copy it to add an offset. */ + if (S && (ELF_ST_TYPE(sym.st_info) == STT_FUNC) && (A != 0)) + errorBelch("%s: function %s with addend %p", oc->fileName, symbol, (void *)A); +#endif + } + if (!S) { + errorBelch("%s: unknown symbol `%s'", oc->fileName, symbol); + return 0; + } + IF_DEBUG(linker,debugBelch( "`%s' resolves to %p\n", symbol, (void*)S )); + } + +#if defined(DEBUG) || defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) \ + || defined(x86_64_HOST_ARCH) + IF_DEBUG(linker,debugBelch("Reloc: P = %p S = %p A = %p\n", + (void*)P, (void*)S, (void*)A )); + checkProddableBlock(oc, (void*)P, sizeof(Elf_Word)); +#endif + +#if defined(sparc_HOST_ARCH) || defined(powerpc_HOST_ARCH) || defined(x86_64_HOST_ARCH) + value = S + A; +#endif + + switch (ELF_R_TYPE(info)) { +# if defined(sparc_HOST_ARCH) + case R_SPARC_WDISP30: + w1 = *pP & 0xC0000000; + w2 = (Elf_Word)((value - P) >> 2); + ASSERT((w2 & 0xC0000000) == 0); + w1 |= w2; + *pP = w1; + break; + case R_SPARC_HI22: + w1 = *pP & 0xFFC00000; + w2 = (Elf_Word)(value >> 10); + ASSERT((w2 & 0xFFC00000) == 0); + w1 |= w2; + *pP = w1; + break; + case R_SPARC_LO10: + w1 = *pP & ~0x3FF; + w2 = (Elf_Word)(value & 0x3FF); + ASSERT((w2 & ~0x3FF) == 0); + w1 |= w2; + *pP = w1; + break; + + /* According to the Sun documentation: + R_SPARC_UA32 + This relocation type resembles R_SPARC_32, except it refers to an + unaligned word. That is, the word to be relocated must be treated + as four separate bytes with arbitrary alignment, not as a word + aligned according to the architecture requirements. + */ + case R_SPARC_UA32: + w2 = (Elf_Word)value; + + // SPARC doesn't do misaligned writes of 32 bit words, + // so we have to do this one byte-at-a-time. + char *pPc = (char*)pP; + pPc[0] = (char) ((Elf_Word)(w2 & 0xff000000) >> 24); + pPc[1] = (char) ((Elf_Word)(w2 & 0x00ff0000) >> 16); + pPc[2] = (char) ((Elf_Word)(w2 & 0x0000ff00) >> 8); + pPc[3] = (char) ((Elf_Word)(w2 & 0x000000ff)); + break; + + case R_SPARC_32: + w2 = (Elf_Word)value; + *pP = w2; + break; +# elif defined(powerpc_HOST_ARCH) + case R_PPC_ADDR16_LO: + *(Elf32_Half*) P = value; + break; + + case R_PPC_ADDR16_HI: + *(Elf32_Half*) P = value >> 16; + break; + + case R_PPC_ADDR16_HA: + *(Elf32_Half*) P = (value + 0x8000) >> 16; + break; + + case R_PPC_ADDR32: + *(Elf32_Word *) P = value; + break; + + case R_PPC_REL32: + *(Elf32_Word *) P = value - P; + break; + + case R_PPC_PLTREL24: + value -= 0x8000; /* See Note [.LCTOC1 in PPC PIC code] */ + /* fallthrough */ + case R_PPC_REL24: + delta = value - P; + + if( delta << 6 >> 6 != delta ) + { + value = (Elf_Addr) (&makeSymbolExtra( oc, ELF_R_SYM(info), value ) + ->jumpIsland); + delta = value - P; + + if( value == 0 || delta << 6 >> 6 != delta ) + { + barf( "Unable to make SymbolExtra for #%d", + ELF_R_SYM(info) ); + return 0; + } + } + + *(Elf_Word *) P = (*(Elf_Word *) P & 0xfc000003) + | (delta & 0x3fffffc); + break; + + case R_PPC_REL16_LO: + *(Elf32_Half*) P = value - P; + break; + + case R_PPC_REL16_HI: + *(Elf32_Half*) P = (value - P) >> 16; + break; + + case R_PPC_REL16_HA: + *(Elf32_Half*) P = (value + 0x8000 - P) >> 16; + break; +# endif + +#if x86_64_HOST_ARCH + case R_X86_64_64: + *(Elf64_Xword *)P = value; + break; + + case R_X86_64_PC32: + { +#if defined(ALWAYS_PIC) + barf("R_X86_64_PC32 relocation, but ALWAYS_PIC."); +#else + StgInt64 off = value - P; + if (off >= 0x7fffffffL || off < -0x80000000L) { + if (X86_64_ELF_NONPIC_HACK) { + StgInt64 pltAddress = + (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) + -> jumpIsland; + off = pltAddress + A - P; + } else { + errorBelch("R_X86_64_PC32 relocation out of range: %s = %" + PRId64 "d\nRecompile %s with -fPIC.", + symbol, off, oc->fileName ); + return 0; + } + } + *(Elf64_Word *)P = (Elf64_Word)off; +#endif + break; + } + + case R_X86_64_PC64: + { + StgInt64 off = value - P; + *(Elf64_Word *)P = (Elf64_Word)off; + break; + } + + case R_X86_64_32: +#if defined(ALWAYS_PIC) + barf("R_X86_64_32 relocation, but ALWAYS_PIC."); +#else + if (value >= 0x7fffffffL) { + if (X86_64_ELF_NONPIC_HACK) { + StgInt64 pltAddress = + (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) + -> jumpIsland; + value = pltAddress + A; + } else { + errorBelch("R_X86_64_32 relocation out of range: %s = %" + PRId64 "d\nRecompile %s with -fPIC.", + symbol, value, oc->fileName ); + return 0; + } + } + *(Elf64_Word *)P = (Elf64_Word)value; +#endif + break; + + case R_X86_64_32S: +#if defined(ALWAYS_PIC) + barf("R_X86_64_32S relocation, but ALWAYS_PIC."); +#else + if ((StgInt64)value > 0x7fffffffL || (StgInt64)value < -0x80000000L) { + if (X86_64_ELF_NONPIC_HACK) { + StgInt64 pltAddress = + (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) + -> jumpIsland; + value = pltAddress + A; + } else { + errorBelch("R_X86_64_32S relocation out of range: %s = %" + PRId64 "d\nRecompile %s with -fPIC.", + symbol, value, oc->fileName ); + return 0; + } + } + *(Elf64_Sword *)P = (Elf64_Sword)value; +#endif + break; +/* These two relocations were introduced in glibc 2.23 and binutils 2.26. + But in order to use them the system which compiles the bindist for GHC needs + to have glibc >= 2.23. So only use them if they're defined. */ +#if defined(R_X86_64_REX_GOTPCRELX) && defined(R_X86_64_GOTPCRELX) + case R_X86_64_REX_GOTPCRELX: + case R_X86_64_GOTPCRELX: +#endif + case R_X86_64_GOTPCREL: + { + StgInt64 gotAddress = (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S)->addr; + StgInt64 off = gotAddress + A - P; + *(Elf64_Word *)P = (Elf64_Word)off; + break; + } +#if defined(dragonfly_HOST_OS) + case R_X86_64_GOTTPOFF: + { +#if defined(ALWAYS_PIC) + barf("R_X86_64_GOTTPOFF relocation, but ALWAYS_PIC."); +#else + /* determine the offset of S to the current thread's tls + area + XXX: Move this to the beginning of function */ + struct tls_info ti; + get_tls_area(0, &ti, sizeof(ti)); + /* make entry in GOT that contains said offset */ + StgInt64 gotEntry = (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), + (S - (Elf64_Addr)(ti.base)))->addr; + *(Elf64_Word *)P = gotEntry + A - P; +#endif + break; + } +#endif + + + + case R_X86_64_PLT32: + { +#if defined(ALWAYS_PIC) + barf("R_X86_64_PLT32 relocation, but ALWAYS_PIC."); +#else + StgInt64 off = value - P; + if (off >= 0x7fffffffL || off < -0x80000000L) { + StgInt64 pltAddress = (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S) + -> jumpIsland; + off = pltAddress + A - P; + } + *(Elf64_Word *)P = (Elf64_Word)off; +#endif + break; + } +#endif + + default: + errorBelch("%s: unhandled ELF relocation(RelA) type %" FMT_Word "\n", + oc->fileName, (W_)ELF_R_TYPE(info)); + return 0; + } + + } + return 1; +} + +int +ocResolve_ELF ( ObjectCode* oc ) +{ + int ok; + Elf_Word i; + char* ehdrC = (char*)(oc->image); + Elf_Ehdr* ehdr = (Elf_Ehdr*) ehdrC; + Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); + const Elf_Word shnum = elf_shnum(ehdr); + + /* Process the relocation sections. */ + for (i = 0; i < shnum; i++) { + if (shdr[i].sh_type == SHT_REL) { + ok = do_Elf_Rel_relocations ( oc, ehdrC, shdr, i ); + if (!ok) return ok; + } + else + if (shdr[i].sh_type == SHT_RELA) { + ok = do_Elf_Rela_relocations ( oc, ehdrC, shdr, i ); + if (!ok) return ok; + } + } + +#if defined(powerpc_HOST_ARCH) || defined(arm_HOST_ARCH) + ocFlushInstructionCache( oc ); +#endif + + return 1; +} + +int ocRunInit_ELF( ObjectCode *oc ) +{ + Elf_Word i; + char* ehdrC = (char*)(oc->image); + Elf_Ehdr* ehdr = (Elf_Ehdr*) ehdrC; + Elf_Shdr* shdr = (Elf_Shdr*) (ehdrC + ehdr->e_shoff); + char* sh_strtab = ehdrC + shdr[elf_shstrndx(ehdr)].sh_offset; + int argc, envc; + char **argv, **envv; + + getProgArgv(&argc, &argv); + getProgEnvv(&envc, &envv); + + // XXX Apparently in some archs .init may be something + // special! See DL_DT_INIT_ADDRESS macro in glibc + // as well as ELF_FUNCTION_PTR_IS_SPECIAL. We've not handled + // it here, please file a bug report if it affects you. + for (i = 0; i < elf_shnum(ehdr); i++) { + init_t *init_start, *init_end, *init; + int is_bss = FALSE; + SectionKind kind = getSectionKind_ELF(&shdr[i], &is_bss); + if (kind == SECTIONKIND_CODE_OR_RODATA + && 0 == memcmp(".init", sh_strtab + shdr[i].sh_name, 5)) { + init_t init_f = (init_t)(oc->sections[i].start); + init_f(argc, argv, envv); + } + + if (kind == SECTIONKIND_INIT_ARRAY) { + char *init_startC = oc->sections[i].start; + init_start = (init_t*)init_startC; + init_end = (init_t*)(init_startC + shdr[i].sh_size); + for (init = init_start; init < init_end; init++) { + (*init)(argc, argv, envv); + } + } + + // XXX could be more strict and assert that it's + // SECTIONKIND_RWDATA; but allowing RODATA seems harmless enough. + if ((kind == SECTIONKIND_RWDATA || kind == SECTIONKIND_CODE_OR_RODATA) + && 0 == memcmp(".ctors", sh_strtab + shdr[i].sh_name, 6)) { + char *init_startC = oc->sections[i].start; + init_start = (init_t*)init_startC; + init_end = (init_t*)(init_startC + shdr[i].sh_size); + // ctors run in reverse + for (init = init_end - 1; init >= init_start; init--) { + (*init)(argc, argv, envv); + } + } + } + + freeProgEnvv(envc, envv); + return 1; +} + +/* + * PowerPC & X86_64 ELF specifics + */ + +#if NEED_SYMBOL_EXTRAS + +int ocAllocateSymbolExtras_ELF( ObjectCode *oc ) +{ + Elf_Ehdr *ehdr; + Elf_Shdr* shdr; + Elf_Word i, shnum; + + ehdr = (Elf_Ehdr *) oc->image; + shdr = (Elf_Shdr *) ( ((char *)oc->image) + ehdr->e_shoff ); + + shnum = elf_shnum(ehdr); + + for( i = 0; i < shnum; i++ ) + if( shdr[i].sh_type == SHT_SYMTAB ) + break; + + if( i == shnum ) + { + // Not having a symbol table is not in principle a problem. + // When an object file has no symbols then the 'strip' program + // typically will remove the symbol table entirely. + IF_DEBUG(linker, debugBelch( "The ELF file %s contains no symtab\n", + oc->archiveMemberName ? oc->archiveMemberName : oc->fileName )); + return 1; + } + + if( shdr[i].sh_entsize != sizeof( Elf_Sym ) ) + { + errorBelch( "The entry size (%d) of the symtab isn't %d\n", + (int) shdr[i].sh_entsize, (int) sizeof( Elf_Sym ) ); + + return 0; + } + + return ocAllocateSymbolExtras( oc, shdr[i].sh_size / sizeof( Elf_Sym ), 0 ); +} + +#endif /* NEED_SYMBOL_EXTRAS */ + +#endif /* elf */ diff --git a/rts/linker/Elf.h b/rts/linker/Elf.h new file mode 100644 index 0000000000..0c33130122 --- /dev/null +++ b/rts/linker/Elf.h @@ -0,0 +1,17 @@ +#ifndef LINKER_ELF_H +#define LINKER_ELF_H + +#include "Rts.h" +#include "LinkerInternals.h" + +#include "BeginPrivate.h" + +int ocVerifyImage_ELF ( ObjectCode* oc ); +int ocGetNames_ELF ( ObjectCode* oc ); +int ocResolve_ELF ( ObjectCode* oc ); +int ocRunInit_ELF ( ObjectCode* oc ); +int ocAllocateSymbolExtras_ELF( ObjectCode *oc ); + +#include "EndPrivate.h" + +#endif /* LINKER_ELF_H */ |