Repository : ssh://darcs.haskell.org//srv/darcs/ghc On branch : master
http://hackage.haskell.org/trac/ghc/changeset/b56e7b20605d742536441ed721a4fa21598782d5 >--------------------------------------------------------------- commit b56e7b20605d742536441ed721a4fa21598782d5 Author: Gregory Wright <[email protected]> Date: Sat Jan 7 09:58:00 2012 -0500 check for failed external symbol lookups (partial fix for #5748) >--------------------------------------------------------------- rts/Linker.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 files changed, 81 insertions(+), 15 deletions(-) diff --git a/rts/Linker.c b/rts/Linker.c index 7fc6d0a..9fb3f68 100644 --- a/rts/Linker.c +++ b/rts/Linker.c @@ -1524,16 +1524,17 @@ lookupSymbol( char *lbl ) /* On OS X 10.3 and later, we use dlsym instead of the old legacy interface. - HACK: On OS X, global symbols are prefixed with an underscore. + HACK: On OS X, all symbols are prefixed with an underscore. However, dlsym wants us to omit the leading underscore from the - symbol name. For now, we simply strip it off here (and ONLY + symbol name -- the dlsym routine puts it back on before searching + for the symbol. For now, we simply strip it off here (and ONLY here). */ IF_DEBUG(linker, debugBelch("lookupSymbol: looking up %s with dlsym\n", lbl)); - ASSERT(lbl[0] == '_'); - return dlsym(dl_prog_handle, lbl+1); + ASSERT(lbl[0] == '_'); + return dlsym(dl_prog_handle, lbl + 1); # else - if(NSIsSymbolNameDefined(lbl)) { + if (NSIsSymbolNameDefined(lbl)) { NSSymbol symbol = NSLookupAndBindSymbol(lbl); return NSAddressOfSymbol(symbol); } else { @@ -4765,7 +4766,7 @@ resolveImports( #endif - for(i=0; i*itemSize < sect->size;i++) + for(i = 0; i * itemSize < sect->size; i++) { // according to otool, reserved1 contains the first index into the indirect symbol table struct nlist *symbol = &nlist[indirectSyms[sect->reserved1+i]]; @@ -4782,9 +4783,11 @@ resolveImports( addr = lookupSymbol(nm); IF_DEBUG(linker, debugBelch("resolveImports: looking up %s, %p\n", nm, addr)); } - if (!addr) + + if (addr == NULL) { - errorBelch("\n%s: unknown symbol `%s'", oc->fileName, nm); + errorBelch("\nlookupSymbol failed in resolveImports\n" + "%s: unknown symbol `%s'", oc->fileName, nm); return 0; } ASSERT(addr); @@ -4809,7 +4812,8 @@ resolveImports( return 1; } -static unsigned long relocateAddress( +static unsigned long +relocateAddress( ObjectCode* oc, int nSections, struct section* sections, @@ -4832,7 +4836,8 @@ static unsigned long relocateAddress( return 0; } -static int relocateSection( +static int +relocateSection( ObjectCode* oc, char *image, struct symtab_command *symLC, struct nlist *nlist, @@ -4857,7 +4862,7 @@ static int relocateSection( relocs = (struct relocation_info*) (image + sect->reloff); - for(i=0;i<n;i++) + for(i = 0; i < n; i++) { #ifdef x86_64_HOST_ARCH struct relocation_info *reloc = &relocs[i]; @@ -4870,6 +4875,15 @@ static int relocateSection( uint64_t baseValue; int type = reloc->r_type; + IF_DEBUG(linker, debugBelch("relocateSection: relocation %d\n", i)); + IF_DEBUG(linker, debugBelch(" : type = %d\n", reloc->r_type)); + IF_DEBUG(linker, debugBelch(" : address = %d\n", reloc->r_address)); + IF_DEBUG(linker, debugBelch(" : symbolnum = %u\n", reloc->r_symbolnum)); + IF_DEBUG(linker, debugBelch(" : pcrel = %d\n", reloc->r_pcrel)); + IF_DEBUG(linker, debugBelch(" : length = %d\n", reloc->r_length)); + IF_DEBUG(linker, debugBelch(" : extern = %d\n", reloc->r_extern)); + IF_DEBUG(linker, debugBelch(" : type = %d\n", reloc->r_type)); + checkProddableBlock(oc,thingPtr); switch(reloc->r_length) { @@ -4898,34 +4912,86 @@ static int relocateSection( reloc->r_length, thing, (char *)baseValue)); if (type == X86_64_RELOC_GOT - || type == X86_64_RELOC_GOT_LOAD) + || type == X86_64_RELOC_GOT_LOAD) { struct nlist *symbol = &nlist[reloc->r_symbolnum]; char *nm = image + symLC->stroff + symbol->n_un.n_strx; + void *addr = NULL; IF_DEBUG(linker, debugBelch("relocateSection: making jump island for %s, extern = %d, X86_64_RELOC_GOT\n", nm, reloc->r_extern)); + ASSERT(reloc->r_extern); - value = (uint64_t) &makeSymbolExtra(oc, reloc->r_symbolnum, (unsigned long)lookupSymbol(nm))->addr; + if (reloc->r_extern == 0) { + errorBelch("\nrelocateSection: global offset table relocation for symbol with r_extern == 0\n"); + } + + if (symbol->n_type & N_EXT) { + // The external bit is set, meaning the symbol is exported, + // and therefore can be looked up in this object module's + // symtab, or it is undefined, meaning dlsym must be used + // to resolve it. + + addr = lookupSymbol(nm); + IF_DEBUG(linker, debugBelch("relocateSection: looked up %s, " + "external X86_64_RELOC_GOT or X86_64_RELOC_GOT_LOAD\n", nm)); + IF_DEBUG(linker, debugBelch(" : addr = %p\n", addr)); + + if (addr == NULL) { + errorBelch("\nlookupSymbol failed in relocateSection (RELOC_GOT)\n" + "%s: unknown symbol `%s'", oc->fileName, nm); + return 0; + } + } else { + IF_DEBUG(linker, debugBelch("relocateSection: %s is not an exported symbol\n", nm)); + + // The symbol is not exported, or defined in another + // module, so it must be in the current object module, + // at the location given by the section index and + // symbol address (symbol->n_value) + + if ((symbol->n_type & N_TYPE) == N_SECT) { + addr = (void *)relocateAddress(oc, nSections, sections, symbol->n_value); + IF_DEBUG(linker, debugBelch("relocateSection: calculated relocation %p of " + "non-external X86_64_RELOC_GOT or X86_64_RELOC_GOT_LOAD\n", + (void *)symbol->n_value)); + IF_DEBUG(linker, debugBelch(" : addr = %p\n", addr)); + } else { + errorBelch("\nrelocateSection: %s is not exported," + " and should be defined in a section, but isn't!\n", nm); + } + } + + value = (uint64_t) &makeSymbolExtra(oc, reloc->r_symbolnum, (unsigned long)addr)->addr; type = X86_64_RELOC_SIGNED; } - else if(reloc->r_extern) + else if (reloc->r_extern) { struct nlist *symbol = &nlist[reloc->r_symbolnum]; char *nm = image + symLC->stroff + symbol->n_un.n_strx; + void *addr = NULL; IF_DEBUG(linker, debugBelch("relocateSection: looking up external symbol %s\n", nm)); IF_DEBUG(linker, debugBelch(" : type = %d\n", symbol->n_type)); IF_DEBUG(linker, debugBelch(" : sect = %d\n", symbol->n_sect)); IF_DEBUG(linker, debugBelch(" : desc = %d\n", symbol->n_desc)); IF_DEBUG(linker, debugBelch(" : value = %p\n", (void *)symbol->n_value)); + if ((symbol->n_type & N_TYPE) == N_SECT) { value = relocateAddress(oc, nSections, sections, symbol->n_value); IF_DEBUG(linker, debugBelch("relocateSection, defined external symbol %s, relocated address %p\n", nm, (void *)value)); } else { - value = (uint64_t) lookupSymbol(nm); + addr = lookupSymbol(nm); + if (addr == NULL) + { + errorBelch("\nlookupSymbol failed in relocateSection (relocate external)\n" + "%s: unknown symbol `%s'", oc->fileName, nm); + return 0; + } + + value = (uint64_t) addr; IF_DEBUG(linker, debugBelch("relocateSection: external symbol %s, address %p\n", nm, (void *)value)); } } _______________________________________________ Cvs-ghc mailing list [email protected] http://www.haskell.org/mailman/listinfo/cvs-ghc
