| //===- StaticResolver.cpp -------------------------------------------------===// |
| // |
| // The MCLinker Project |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| #include <mcld/LD/StaticResolver.h> |
| #include <mcld/LD/LDSymbol.h> |
| #include <mcld/Support/MsgHandling.h> |
| |
| using namespace mcld; |
| |
| //========================== |
| // StaticResolver |
| StaticResolver::~StaticResolver() |
| { |
| } |
| |
| bool StaticResolver::resolve(ResolveInfo& __restrict__ pOld, |
| const ResolveInfo& __restrict__ pNew, |
| bool &pOverride) const |
| { |
| |
| /* The state table itself. |
| * The first index is a link_row and the second index is a bfd_link_hash_type. |
| * |
| * Cs -> all rest kind of common (d_C, wd_C) |
| * Is -> all kind of indeirect |
| */ |
| static const enum LinkAction link_action[LAST_ORD][LAST_ORD] = |
| { |
| /* new\old U w_U d_U wd_U D w_D d_D wd_D C w_C, Cs, Is */ |
| /* U */ {NOACT, UND, UND, UND, NOACT, NOACT, DUND, DUND, NOACT, NOACT, NOACT, REFC }, |
| /* w_U */ {NOACT, NOACT, NOACT, WEAK, NOACT, NOACT, DUNDW, DUNDW, NOACT, NOACT, NOACT, REFC }, |
| /* d_U */ {NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, REFC }, |
| /* wd_U */ {NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, REFC }, |
| /* D */ {DEF, DEF, DEF, DEF, MDEF, DEF, DEF, DEF, CDEF, CDEF, CDEF, MDEF }, |
| /* w_D */ {DEFW, DEFW, DEFW, DEFW, NOACT, NOACT, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT}, |
| /* d_D */ {MDEFD, MDEFD, DEFD, DEFD, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, MDEF }, |
| /* wd_D */ {MDEFWD, MDEFWD, DEFWD, DEFWD, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT}, |
| /* C */ {COM, COM, COM, COM, CREF, COM, COM, COM, MBIG, COM, BIG, REFC }, |
| /* w_C */ {COM, COM, COM, COM, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, NOACT, REFC }, |
| /* Cs */ {COM, COM, COM, COM, NOACT, NOACT, NOACT, NOACT, MBIG, MBIG, MBIG, REFC }, |
| /* Is */ {IND, IND, IND, IND, MDEF, IND, IND, IND, CIND, CIND, CIND, MIND } |
| }; |
| |
| // Special cases: |
| // * when a dynamic defined symbol meets a dynamic weak defined symbol, act |
| // noting. |
| // * when a undefined symbol meets a dynamic defined symbol, override by |
| // dynamic defined first, then recover back to undefined symbol later. |
| // * when a dynamic defined symbol meets a undefined symbol or a weak |
| // undefined symbol, do not override, instead of marking. |
| // * When a undefined symbol meets a dynamic defined symbol or a weak |
| // undefined symbol meets a dynamic defined symbol, should override. |
| // * When a common symbol meets a weak common symbol, adjust the size of |
| // common symbol (ref: Google gold linker: resolve.cc) |
| |
| unsigned int row = getOrdinate(pNew); |
| unsigned int col = getOrdinate(pOld); |
| |
| bool cycle = false; |
| pOverride = false; |
| ResolveInfo* old = &pOld; |
| LinkAction action; |
| do { |
| cycle = false; |
| action = link_action[row][col]; |
| |
| switch(action) { |
| case FAIL: { /* abort. */ |
| fatal(diag::fail_sym_resolution) |
| << __FILE__ << __LINE__ |
| << "mclinker@googlegroups.com"; |
| return false; |
| } |
| case NOACT: { /* no action. */ |
| pOverride = false; |
| old->overrideVisibility(pNew); |
| break; |
| } |
| case UND: /* override by symbol undefined symbol. */ |
| case WEAK: /* override by symbol weak undefined. */ |
| case DEF: /* override by symbol defined. */ |
| case DEFW: /* override by symbol weak defined. */ |
| case DEFD: /* override by symbol dynamic defined. */ |
| case DEFWD: /* override by symbol dynamic weak defined. */ |
| case COM: { /* override by symbol common defined. */ |
| pOverride = true; |
| old->override(pNew); |
| break; |
| } |
| case MDEFD: /* mark symbol dynamic defined. */ |
| case MDEFWD: { /* mark symbol dynamic weak defined. */ |
| uint32_t binding = old->binding(); |
| old->override(pNew); |
| old->setBinding(binding); |
| ignore(diag::mark_dynamic_defined) << old->name(); |
| pOverride = true; |
| break; |
| } |
| case DUND: |
| case DUNDW: { |
| old->overrideVisibility(pNew); |
| old->setDynamic(); |
| pOverride = false; |
| break; |
| } |
| case CREF: { /* Possibly warn about common reference to defined symbol. */ |
| // A common symbol does not override a definition. |
| ignore(diag::comm_refer_to_define) << old->name(); |
| pOverride = false; |
| break; |
| } |
| case CDEF: { /* redefine existing common symbol. */ |
| // We've seen a common symbol and now we see a definition. The |
| // definition overrides. |
| // |
| // NOTE: m_Mesg uses 'name' instead of `name' for being compatible to GNU ld. |
| ignore(diag::redefine_common) << old->name(); |
| old->override(pNew); |
| pOverride = true; |
| break; |
| } |
| case BIG: { /* override by symbol common using largest size. */ |
| if (old->size() < pNew.size()) |
| old->setSize(pNew.size()); |
| old->overrideAttributes(pNew); |
| old->overrideVisibility(pNew); |
| pOverride = true; |
| break; |
| } |
| case MBIG: { /* mark common symbol by larger size. */ |
| if (old->size() < pNew.size()) |
| old->setSize(pNew.size()); |
| old->overrideVisibility(pNew); |
| pOverride = false; |
| break; |
| } |
| case CIND: { /* mark indirect symbol from existing common symbol. */ |
| ignore(diag::indirect_refer_to_common) << old->name(); |
| } |
| /* Fall through */ |
| case IND: { /* override by indirect symbol. */ |
| if (NULL == pNew.link()) { |
| fatal(diag::indirect_refer_to_inexist) << pNew.name(); |
| break; |
| } |
| |
| /** Should detect the loop of indirect symbol during file reading **/ |
| // if (pNew.link()->isIndirect() && pNew.link()->link() == &pNew) { |
| // m_Mesg = "indirect symbol `"+pNew.name()+"' to `"+pNew.link()->name()+"' is a loop."; |
| // return Resolver::Abort; |
| //} |
| |
| // change the old symbol to the indirect symbol |
| old->setLink(pNew.link()); |
| pOverride = true; |
| break; |
| } |
| case MIND: { /* multiple indirect symbols. */ |
| // it is OK if they both point to the same symbol |
| if (old->link() == pNew.link()) { |
| pOverride = false; |
| break; |
| } |
| } |
| /* Fall through */ |
| case MDEF: { /* multiple definition error. */ |
| error(diag::multiple_definitions) << pNew.name(); |
| break; |
| } |
| case REFC: { /* Mark indirect symbol referenced and then CYCLE. */ |
| if (NULL == old->link()) { |
| fatal(diag::indirect_refer_to_inexist) << old->name(); |
| break; |
| } |
| |
| old = old->link(); |
| col = getOrdinate(*old); |
| cycle = true; |
| break; |
| } |
| default: { |
| error(diag::undefined_situation) << action << old->name() << pNew.name(); |
| return false; |
| } |
| } // end of the big switch (action) |
| } while(cycle); |
| return true; |
| } |
| |
