int64_t decodeAddend()

in rts/linker/MachO.c [65:157]

• 66 lines of code
• 11 McCabe index (conditional complexity)

int64_t decodeAddend(ObjectCode * oc, Section * section,
                     MachORelocationInfo * ri);
void encodeAddend(ObjectCode * oc, Section * section,
                  MachORelocationInfo * ri, int64_t addend);

/* finding and making stubs. We don't need to care about the symbol they
 * represent. As long as two stubs point to the same address, they are identical
 */
bool findStub(Section * section, void ** addr);
bool makeStub(Section * section, void ** addr);
void freeStubs(Section * section);

/* Global Offset Table logic */
bool isGotLoad(MachORelocationInfo * ri);
bool needGotSlot(MachONList * symbol);
bool makeGot(ObjectCode * oc);
void freeGot(ObjectCode * oc);
#endif /* aarch64_HOST_ARCH */

#if defined(ios_HOST_OS)
/* on iOS we need to ensure we only have r+w or r+x pages hence we need to mmap
 * pages r+w and r+x mprotect them later on.
 */
bool ocMprotect_MachO( ObjectCode *oc );
#endif /* ios_HOST_OS */

/*
 * Initialize some common data in the object code so we don't have to
 * continuously look up the addresses.
 */
void
ocInit_MachO(ObjectCode * oc)
{
    ocDeinit_MachO(oc);

    oc->info = (struct ObjectCodeFormatInfo*)stgCallocBytes(
                1, sizeof *oc->info,
                "ocInit_MachO(ObjectCodeFormatInfo)");
    oc->info->header  = (MachOHeader *) oc->image;
    oc->info->symCmd  = NULL;
    oc->info->segCmd  = NULL;
    oc->info->dsymCmd = NULL;

    MachOLoadCommand *lc = (MachOLoadCommand*)(oc->image + sizeof(MachOHeader));
    for(size_t i = 0; i < oc->info->header->ncmds; i++) {
        if (lc->cmd == LC_SEGMENT || lc->cmd == LC_SEGMENT_64) {
            oc->info->segCmd = (MachOSegmentCommand*) lc;
        }
        else if (lc->cmd == LC_SYMTAB) {
            oc->info->symCmd = (MachOSymtabCommand*) lc;
        }
        else if (lc->cmd == LC_DYSYMTAB) {
            oc->info->dsymCmd = (MachODsymtabCommand*) lc;
        }
        lc = (MachOLoadCommand *) ( ((char*)lc) + lc->cmdsize );
    }
    if (NULL == oc->info->segCmd) {
        barf("ocGetNames_MachO: no segment load command");
    }

    oc->info->macho_sections = (MachOSection*) (oc->info->segCmd+1);
    oc->n_sections = oc->info->segCmd->nsects;

    oc->info->nlist = oc->info->symCmd == NULL
              ? NULL
              : (MachONList *)(oc->image + oc->info->symCmd->symoff);
    oc->info->names = oc->info->symCmd == NULL
              ? NULL
              : (oc->image + oc->info->symCmd->stroff);

    /* If we have symbols, allocate and fill the macho_symbols
     * This will make relocation easier.
     */
    oc->info->n_macho_symbols = 0;
    oc->info->macho_symbols = NULL;

    if(NULL != oc->info->nlist) {
        oc->info->n_macho_symbols = oc->info->symCmd->nsyms;
        oc->info->macho_symbols = (MachOSymbol*)stgCallocBytes(
                                    oc->info->symCmd->nsyms,
                                    sizeof(MachOSymbol),
                                    "ocInit_MachO(MachOSymbol)");
        for(uint32_t i = 0; i < oc->info->symCmd->nsyms; i++) {
            oc->info->macho_symbols[i].name  = oc->info->names
                                             + oc->info->nlist[i].n_un.n_strx;
            oc->info->macho_symbols[i].nlist = &oc->info->nlist[i];
             /* we don't have an address for this symbol yet; this will be
              * populated during ocGetNames_MachO. hence addr = NULL
              */
            oc->info->macho_symbols[i].addr  = NULL;
        }
    }
}