+
+/* --------------------------------------------------------------------------
+ * Mach-O specifics
+ * ------------------------------------------------------------------------*/
+
+#if defined(OBJFORMAT_MACHO)
+
+/*
+ Initial support for MachO linking on Darwin/MacOS X on PowerPC chips
+ by Wolfgang Thaller (wolfgang.thaller@gmx.net)
+
+ I hereby formally apologize for the hackish nature of this code.
+ Things that need to be done:
+ *) get common symbols and .bss sections to work properly.
+ Haskell modules seem to work, but C modules can cause problems
+ *) implement ocVerifyImage_MachO
+ *) add more sanity checks. The current code just has to segfault if there's a
+ broken .o file.
+*/
+
+static int ocVerifyImage_MachO(ObjectCode* oc)
+{
+ // FIXME: do some verifying here
+ return 1;
+}
+
+static void resolveImports(
+ ObjectCode* oc,
+ char *image,
+ struct symtab_command *symLC,
+ struct section *sect, // ptr to lazy or non-lazy symbol pointer section
+ unsigned long *indirectSyms,
+ struct nlist *nlist)
+{
+ unsigned i;
+
+ for(i=0;i*4<sect->size;i++)
+ {
+ // according to otool, reserved1 contains the first index into the indirect symbol table
+ struct nlist *symbol = &nlist[indirectSyms[sect->reserved1+i]];
+ char *nm = image + symLC->stroff + symbol->n_un.n_strx;
+ void *addr = NULL;
+
+ if((symbol->n_type & N_TYPE) == N_UNDF
+ && (symbol->n_type & N_EXT) && (symbol->n_value != 0))
+ addr = (void*) (symbol->n_value);
+ else if((addr = lookupLocalSymbol(oc,nm)) != NULL)
+ ;
+ else
+ addr = lookupSymbol(nm);
+ if(!addr)
+ {
+ fprintf(stderr, "not found: %s\n", nm);
+ abort();
+ }
+ ASSERT(addr);
+ ((void**)(image + sect->offset))[i] = addr;
+ }
+}
+
+static void relocateSection(char *image,
+ struct symtab_command *symLC, struct nlist *nlist,
+ struct section* sections, struct section *sect)
+{
+ struct relocation_info *relocs;
+ int i,n;
+
+ if(!strcmp(sect->sectname,"__la_symbol_ptr"))
+ return;
+ else if(!strcmp(sect->sectname,"__nl_symbol_ptr"))
+ return;
+
+ n = sect->nreloc;
+ relocs = (struct relocation_info*) (image + sect->reloff);
+
+ for(i=0;i<n;i++)
+ {
+ if(relocs[i].r_address & R_SCATTERED)
+ {
+ struct scattered_relocation_info *scat =
+ (struct scattered_relocation_info*) &relocs[i];
+
+ if(!scat->r_pcrel)
+ {
+ if(scat->r_length == 2 && scat->r_type == GENERIC_RELOC_VANILLA)
+ {
+ unsigned long* word = (unsigned long*) (image + sect->offset + scat->r_address);
+
+ *word = scat->r_value + sect->offset + ((long) image);
+ }
+ }
+
+ continue; // FIXME: I hope it's OK to ignore all the others.
+ }
+ else
+ {
+ struct relocation_info *reloc = &relocs[i];
+ if(reloc->r_pcrel && !reloc->r_extern)
+ continue;
+
+ if(!reloc->r_pcrel
+ && reloc->r_length == 2
+ && reloc->r_type == GENERIC_RELOC_VANILLA)
+ {
+ unsigned long* word = (unsigned long*) (image + sect->offset + reloc->r_address);
+
+ if(!reloc->r_extern)
+ {
+ long delta =
+ sections[reloc->r_symbolnum-1].offset
+ - sections[reloc->r_symbolnum-1].addr
+ + ((long) image);
+
+ *word += delta;
+ }
+ else
+ {
+ struct nlist *symbol = &nlist[reloc->r_symbolnum];
+ char *nm = image + symLC->stroff + symbol->n_un.n_strx;
+ *word = (unsigned long) (lookupSymbol(nm));
+ ASSERT(*word);
+ }
+ continue;
+ }
+ fprintf(stderr, "unknown reloc\n");
+ abort();
+ ASSERT(2 + 2 == 5);
+ }
+ }
+}
+
+static int ocGetNames_MachO(ObjectCode* oc)
+{
+ char *image = (char*) oc->image;
+ struct mach_header *header = (struct mach_header*) image;
+ struct load_command *lc = (struct load_command*) (image + sizeof(struct mach_header));
+ unsigned i,curSymbol;
+ struct segment_command *segLC = NULL;
+ struct section *sections, *la_ptrs = NULL, *nl_ptrs = NULL;
+ struct symtab_command *symLC = NULL;
+ struct dysymtab_command *dsymLC = NULL;
+ struct nlist *nlist;
+ unsigned long commonSize = 0;
+ char *commonStorage = NULL;
+ unsigned long commonCounter;
+
+ for(i=0;i<header->ncmds;i++)
+ {
+ if(lc->cmd == LC_SEGMENT)
+ segLC = (struct segment_command*) lc;
+ else if(lc->cmd == LC_SYMTAB)
+ symLC = (struct symtab_command*) lc;
+ else if(lc->cmd == LC_DYSYMTAB)
+ dsymLC = (struct dysymtab_command*) lc;
+ lc = (struct load_command *) ( ((char*)lc) + lc->cmdsize );
+ }
+
+ sections = (struct section*) (segLC+1);
+ nlist = (struct nlist*) (image + symLC->symoff);
+
+ for(i=0;i<segLC->nsects;i++)
+ {
+ if(!strcmp(sections[i].sectname,"__la_symbol_ptr"))
+ la_ptrs = §ions[i];
+ else if(!strcmp(sections[i].sectname,"__nl_symbol_ptr"))
+ nl_ptrs = §ions[i];
+
+ // for now, only add __text and __const to the sections table
+ else if(!strcmp(sections[i].sectname,"__text"))
+ addSection(oc, SECTIONKIND_CODE_OR_RODATA,
+ (void*) (image + sections[i].offset),
+ (void*) (image + sections[i].offset + sections[i].size));
+ else if(!strcmp(sections[i].sectname,"__const"))
+ addSection(oc, SECTIONKIND_RWDATA,
+ (void*) (image + sections[i].offset),
+ (void*) (image + sections[i].offset + sections[i].size));
+ else if(!strcmp(sections[i].sectname,"__data"))
+ addSection(oc, SECTIONKIND_RWDATA,
+ (void*) (image + sections[i].offset),
+ (void*) (image + sections[i].offset + sections[i].size));
+ }
+
+ // count external symbols defined here
+ oc->n_symbols = 0;
+ for(i=dsymLC->iextdefsym;i<dsymLC->iextdefsym+dsymLC->nextdefsym;i++)
+ {
+ if((nlist[i].n_type & N_TYPE) == N_SECT)
+ oc->n_symbols++;
+ }
+ for(i=0;i<symLC->nsyms;i++)
+ {
+ if((nlist[i].n_type & N_TYPE) == N_UNDF
+ && (nlist[i].n_type & N_EXT) && (nlist[i].n_value != 0))
+ {
+ commonSize += nlist[i].n_value;
+ oc->n_symbols++;
+ }
+ }
+ oc->symbols = stgMallocBytes(oc->n_symbols * sizeof(char*),
+ "ocGetNames_MachO(oc->symbols)");
+
+ // insert symbols into hash table
+ for(i=dsymLC->iextdefsym,curSymbol=0;i<dsymLC->iextdefsym+dsymLC->nextdefsym;i++)
+ {
+ if((nlist[i].n_type & N_TYPE) == N_SECT)
+ {
+ char *nm = image + symLC->stroff + nlist[i].n_un.n_strx;
+ ghciInsertStrHashTable(oc->fileName, symhash, nm, image +
+ sections[nlist[i].n_sect-1].offset
+ - sections[nlist[i].n_sect-1].addr
+ + nlist[i].n_value);
+ oc->symbols[curSymbol++] = nm;
+ }
+ }
+
+ // insert local symbols into lochash
+ for(i=dsymLC->ilocalsym;i<dsymLC->ilocalsym+dsymLC->nlocalsym;i++)
+ {
+ if((nlist[i].n_type & N_TYPE) == N_SECT)
+ {
+ char *nm = image + symLC->stroff + nlist[i].n_un.n_strx;
+ ghciInsertStrHashTable(oc->fileName, oc->lochash, nm, image +
+ sections[nlist[i].n_sect-1].offset
+ - sections[nlist[i].n_sect-1].addr
+ + nlist[i].n_value);
+ }
+ }
+
+
+ commonStorage = stgCallocBytes(1,commonSize,"ocGetNames_MachO(common symbols)");
+ commonCounter = (unsigned long)commonStorage;
+ for(i=0;i<symLC->nsyms;i++)
+ {
+ if((nlist[i].n_type & N_TYPE) == N_UNDF
+ && (nlist[i].n_type & N_EXT) && (nlist[i].n_value != 0))
+ {
+ char *nm = image + symLC->stroff + nlist[i].n_un.n_strx;
+ unsigned long sz = nlist[i].n_value;
+
+ nlist[i].n_value = commonCounter;
+
+ ghciInsertStrHashTable(oc->fileName, symhash, nm, (void*)commonCounter);
+ oc->symbols[curSymbol++] = nm;
+
+ commonCounter += sz;
+ }
+ }
+ return 1;
+}
+
+static int ocResolve_MachO(ObjectCode* oc)
+{
+ char *image = (char*) oc->image;
+ struct mach_header *header = (struct mach_header*) image;
+ struct load_command *lc = (struct load_command*) (image + sizeof(struct mach_header));
+ unsigned i;
+ struct segment_command *segLC = NULL;
+ struct section *sections, *la_ptrs = NULL, *nl_ptrs = NULL;
+ struct symtab_command *symLC = NULL;
+ struct dysymtab_command *dsymLC = NULL;
+ struct nlist *nlist;
+ unsigned long *indirectSyms;
+
+ for(i=0;i<header->ncmds;i++)
+ {
+ if(lc->cmd == LC_SEGMENT)
+ segLC = (struct segment_command*) lc;
+ else if(lc->cmd == LC_SYMTAB)
+ symLC = (struct symtab_command*) lc;
+ else if(lc->cmd == LC_DYSYMTAB)
+ dsymLC = (struct dysymtab_command*) lc;
+ lc = (struct load_command *) ( ((char*)lc) + lc->cmdsize );
+ }
+
+ sections = (struct section*) (segLC+1);
+ nlist = (struct nlist*) (image + symLC->symoff);
+
+ for(i=0;i<segLC->nsects;i++)
+ {
+ if(!strcmp(sections[i].sectname,"__la_symbol_ptr"))
+ la_ptrs = §ions[i];
+ else if(!strcmp(sections[i].sectname,"__nl_symbol_ptr"))
+ nl_ptrs = §ions[i];
+ }
+
+ indirectSyms = (unsigned long*) (image + dsymLC->indirectsymoff);
+
+ if(la_ptrs)
+ resolveImports(oc,image,symLC,la_ptrs,indirectSyms,nlist);
+ if(nl_ptrs)
+ resolveImports(oc,image,symLC,nl_ptrs,indirectSyms,nlist);
+
+ for(i=0;i<segLC->nsects;i++)
+ {
+ relocateSection(image,symLC,nlist,sections,§ions[i]);
+ }
+
+ /* Free the local symbol table; we won't need it again. */
+ freeHashTable(oc->lochash, NULL);
+ oc->lochash = NULL;
+ return 1;
+}
+
+#endif