* incremental.cc
[deliverable/binutils-gdb.git] / gold / resolve.cc
index bd327e88a58466f8d8b53fdd0cbd470eae937640..29d9d79c7a46c682215896c7b4d315e855e43edb 100644 (file)
@@ -1,6 +1,6 @@
 // resolve.cc -- symbol resolution for gold
 
-// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
@@ -178,6 +178,7 @@ symbol_to_bits(elfcpp::STB binding, bool is_dynamic,
   switch (binding)
     {
     case elfcpp::STB_GLOBAL:
+    case elfcpp::STB_GNU_UNIQUE:
       bits = global_flag;
       break;
 
@@ -217,6 +218,8 @@ symbol_to_bits(elfcpp::STB binding, bool is_dynamic,
     default:
       if (type == elfcpp::STT_COMMON)
        bits |= common_flag;
+      else if (!is_ordinary && Symbol::is_common_shndx(shndx))
+       bits |= common_flag;
       else
         bits |= def_flag;
       break;
@@ -242,10 +245,10 @@ Symbol_table::resolve(Sized_symbol<size>* to,
                      unsigned int orig_st_shndx,
                      Object* object, const char* version)
 {
-  if (object->target()->has_resolve())
+  if (parameters->target().has_resolve())
     {
       Sized_target<size, big_endian>* sized_target;
-      sized_target = object->sized_target<size, big_endian>();
+      sized_target = parameters->sized_target<size, big_endian>();
       sized_target->resolve(to, sym, object, version);
       return;
     }
@@ -255,6 +258,21 @@ Symbol_table::resolve(Sized_symbol<size>* to,
       // Record that we've seen this symbol in a regular object.
       to->set_in_reg();
     }
+  else if (st_shndx == elfcpp::SHN_UNDEF
+           && (to->visibility() == elfcpp::STV_HIDDEN
+               || to->visibility() == elfcpp::STV_INTERNAL))
+    {
+      // A dynamic object cannot reference a hidden or internal symbol
+      // defined in another object.
+      gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
+                   (to->visibility() == elfcpp::STV_HIDDEN
+                    ? "hidden"
+                    : "internal"),
+                   to->demangled_name().c_str(),
+                   to->object()->name().c_str(),
+                   object->name().c_str());
+      return;
+    }
   else
     {
       // Record that we've seen this symbol in a dynamic object.
@@ -279,42 +297,19 @@ Symbol_table::resolve(Sized_symbol<size>* to,
         }
     }
 
-  unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
-                                         object->is_dynamic(),
-                                        st_shndx, is_ordinary,
-                                         sym.get_st_type());
-
-  bool adjust_common_sizes;
-  if (Symbol_table::should_override(to, frombits, object,
-                                   &adjust_common_sizes))
-    {
-      typename Sized_symbol<size>::Size_type tosize = to->symsize();
-
-      this->override(to, sym, st_shndx, is_ordinary, object, version);
-
-      if (adjust_common_sizes && tosize > to->symsize())
-        to->set_symsize(tosize);
-    }
-  else
-    {
-      if (adjust_common_sizes && sym.get_st_size() > to->symsize())
-        to->set_symsize(sym.get_st_size());
-      // The ELF ABI says that even for a reference to a symbol we
-      // merge the visibility.
-      to->override_visibility(sym.get_st_visibility());
-    }
-
   // A new weak undefined reference, merging with an old weak
   // reference, could be a One Definition Rule (ODR) violation --
   // especially if the types or sizes of the references differ.  We'll
   // store such pairs and look them up later to make sure they
-  // actually refer to the same lines of code.  (Note: not all ODR
-  // violations can be found this way, and not everything this finds
-  // is an ODR violation.  But it's helpful to warn about.)
+  // actually refer to the same lines of code.  We also check
+  // combinations of weak and strong, which might occur if one case is
+  // inline and the other is not.  (Note: not all ODR violations can
+  // be found this way, and not everything this finds is an ODR
+  // violation.  But it's helpful to warn about.)
   bool to_is_ordinary;
   if (parameters->options().detect_odr_violations()
-      && sym.get_st_bind() == elfcpp::STB_WEAK
-      && to->binding() == elfcpp::STB_WEAK
+      && (sym.get_st_bind() == elfcpp::STB_WEAK
+         || to->binding() == elfcpp::STB_WEAK)
       && orig_st_shndx != elfcpp::SHN_UNDEF
       && to->shndx(&to_is_ordinary) != elfcpp::SHN_UNDEF
       && to_is_ordinary
@@ -333,6 +328,62 @@ Symbol_table::resolve(Sized_symbol<size>* to,
       this->candidate_odr_violations_[to->name()].insert(fromloc);
       this->candidate_odr_violations_[to->name()].insert(toloc);
     }
+
+  unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
+                                         object->is_dynamic(),
+                                        st_shndx, is_ordinary,
+                                         sym.get_st_type());
+
+  bool adjust_common_sizes;
+  bool adjust_dyndef;
+  typename Sized_symbol<size>::Size_type tosize = to->symsize();
+  if (Symbol_table::should_override(to, frombits, OBJECT, object,
+                                   &adjust_common_sizes,
+                                   &adjust_dyndef))
+    {
+      elfcpp::STB tobinding = to->binding();
+      this->override(to, sym, st_shndx, is_ordinary, object, version);
+      if (adjust_common_sizes && tosize > to->symsize())
+        to->set_symsize(tosize);
+      if (adjust_dyndef)
+       {
+         // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
+         // Remember which kind of UNDEF it was for future reference.
+         to->set_undef_binding(tobinding);
+       }
+    }
+  else
+    {
+      if (adjust_common_sizes && sym.get_st_size() > tosize)
+        to->set_symsize(sym.get_st_size());
+      if (adjust_dyndef)
+       {
+         // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
+         // Remember which kind of UNDEF it was.
+         to->set_undef_binding(sym.get_st_bind());
+       }
+      // The ELF ABI says that even for a reference to a symbol we
+      // merge the visibility.
+      to->override_visibility(sym.get_st_visibility());
+    }
+
+  if (adjust_common_sizes && parameters->options().warn_common())
+    {
+      if (tosize > sym.get_st_size())
+       Symbol_table::report_resolve_problem(false,
+                                            _("common of '%s' overriding "
+                                              "smaller common"),
+                                            to, OBJECT, object);
+      else if (tosize < sym.get_st_size())
+       Symbol_table::report_resolve_problem(false,
+                                            _("common of '%s' overidden by "
+                                              "larger common"),
+                                            to, OBJECT, object);
+      else
+       Symbol_table::report_resolve_problem(false,
+                                            _("multiple common of '%s'"),
+                                            to, OBJECT, object);
+    }
 }
 
 // Handle the core of symbol resolution.  This is called with the
@@ -344,9 +395,12 @@ Symbol_table::resolve(Sized_symbol<size>* to,
 
 bool
 Symbol_table::should_override(const Symbol* to, unsigned int frombits,
-                              Object* object, bool* adjust_common_sizes)
+                              Defined defined, Object* object,
+                             bool* adjust_common_sizes,
+                             bool* adjust_dyndef)
 {
   *adjust_common_sizes = false;
+  *adjust_dyndef = false;
 
   unsigned int tobits;
   if (to->source() == Symbol::IS_UNDEFINED)
@@ -402,17 +456,13 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
       // --just-symbols, then don't warn.  This is for compatibility
       // with the GNU linker.  FIXME: This is a hack.
       if ((to->source() == Symbol::FROM_OBJECT && to->object()->just_symbols())
-          || object->just_symbols())
+          || (object != NULL && object->just_symbols()))
         return false;
 
-      // FIXME: Do a better job of reporting locations.
-      gold_error(_("%s: multiple definition of %s"),
-                object != NULL ? object->name().c_str() : _("command line"),
-                to->demangled_name().c_str());
-      gold_error(_("%s: previous definition here"),
-                (to->source() == Symbol::FROM_OBJECT
-                 ? to->object()->name().c_str()
-                 : _("command line")));
+      if (!parameters->options().muldefs())
+       Symbol_table::report_resolve_problem(true,
+                                            _("multiple definition of '%s'"),
+                                            to, defined, object);
       return false;
 
     case WEAK_DEF * 16 + DEF:
@@ -447,8 +497,12 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
     case DYN_COMMON * 16 + DEF:
     case DYN_WEAK_COMMON * 16 + DEF:
       // We've seen a common symbol and now we see a definition.  The
-      // definition overrides.  FIXME: We should optionally issue, version a
-      // warning.
+      // definition overrides.
+      if (parameters->options().warn_common())
+       Symbol_table::report_resolve_problem(false,
+                                            _("definition of '%s' overriding "
+                                              "common"),
+                                            to, defined, object);
       return true;
 
     case DEF * 16 + WEAK_DEF:
@@ -478,7 +532,12 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
     case DYN_COMMON * 16 + WEAK_DEF:
     case DYN_WEAK_COMMON * 16 + WEAK_DEF:
       // A weak definition does override a definition in a dynamic
-      // object.  FIXME: We should optionally issue a warning.
+      // object.
+      if (parameters->options().warn_common())
+       Symbol_table::report_resolve_problem(false,
+                                            _("definition of '%s' overriding "
+                                              "dynamic common definition"),
+                                            to, defined, object);
       return true;
 
     case DEF * 16 + DYN_DEF:
@@ -489,12 +548,17 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
       return false;
 
     case UNDEF * 16 + DYN_DEF:
-    case WEAK_UNDEF * 16 + DYN_DEF:
     case DYN_UNDEF * 16 + DYN_DEF:
     case DYN_WEAK_UNDEF * 16 + DYN_DEF:
       // Use a dynamic definition if we have a reference.
       return true;
 
+    case WEAK_UNDEF * 16 + DYN_DEF:
+      // When overriding a weak undef by a dynamic definition,
+      // we need to remember that the original undef was weak.
+      *adjust_dyndef = true;
+      return true;
+
     case COMMON * 16 + DYN_DEF:
     case WEAK_COMMON * 16 + DYN_DEF:
     case DYN_COMMON * 16 + DYN_DEF:
@@ -512,12 +576,22 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
       return false;
 
     case UNDEF * 16 + DYN_WEAK_DEF:
-    case WEAK_UNDEF * 16 + DYN_WEAK_DEF:
+      // When overriding an undef by a dynamic weak definition,
+      // we need to remember that the original undef was not weak.
+      *adjust_dyndef = true;
+      return true;
+
     case DYN_UNDEF * 16 + DYN_WEAK_DEF:
     case DYN_WEAK_UNDEF * 16 + DYN_WEAK_DEF:
       // Use a weak dynamic definition if we have a reference.
       return true;
 
+    case WEAK_UNDEF * 16 + DYN_WEAK_DEF:
+      // When overriding a weak undef by a dynamic definition,
+      // we need to remember that the original undef was weak.
+      *adjust_dyndef = true;
+      return true;
+
     case COMMON * 16 + DYN_WEAK_DEF:
     case WEAK_COMMON * 16 + DYN_WEAK_DEF:
     case DYN_COMMON * 16 + DYN_WEAK_DEF:
@@ -528,12 +602,16 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
 
     case DEF * 16 + UNDEF:
     case WEAK_DEF * 16 + UNDEF:
-    case DYN_DEF * 16 + UNDEF:
-    case DYN_WEAK_DEF * 16 + UNDEF:
     case UNDEF * 16 + UNDEF:
       // A new undefined reference tells us nothing.
       return false;
 
+    case DYN_DEF * 16 + UNDEF:
+    case DYN_WEAK_DEF * 16 + UNDEF:
+      // For a dynamic def, we need to remember which kind of undef we see.
+      *adjust_dyndef = true;
+      return false;
+
     case WEAK_UNDEF * 16 + UNDEF:
     case DYN_UNDEF * 16 + UNDEF:
     case DYN_WEAK_UNDEF * 16 + UNDEF:
@@ -549,8 +627,6 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
 
     case DEF * 16 + WEAK_UNDEF:
     case WEAK_DEF * 16 + WEAK_UNDEF:
-    case DYN_DEF * 16 + WEAK_UNDEF:
-    case DYN_WEAK_DEF * 16 + WEAK_UNDEF:
     case UNDEF * 16 + WEAK_UNDEF:
     case WEAK_UNDEF * 16 + WEAK_UNDEF:
     case DYN_UNDEF * 16 + WEAK_UNDEF:
@@ -562,6 +638,12 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
       // A new weak undefined reference tells us nothing.
       return false;
 
+    case DYN_DEF * 16 + WEAK_UNDEF:
+    case DYN_WEAK_DEF * 16 + WEAK_UNDEF:
+      // For a dynamic def, we need to remember which kind of undef we see.
+      *adjust_dyndef = true;
+      return false;
+
     case DEF * 16 + DYN_UNDEF:
     case WEAK_DEF * 16 + DYN_UNDEF:
     case DYN_DEF * 16 + DYN_UNDEF:
@@ -594,6 +676,11 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
 
     case DEF * 16 + COMMON:
       // A common symbol does not override a definition.
+      if (parameters->options().warn_common())
+       Symbol_table::report_resolve_problem(false,
+                                            _("common '%s' overridden by "
+                                              "previous definition"),
+                                            to, defined, object);
       return false;
 
     case WEAK_DEF * 16 + COMMON:
@@ -699,18 +786,77 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
     }
 }
 
+// Issue an error or warning due to symbol resolution.  IS_ERROR
+// indicates an error rather than a warning.  MSG is the error
+// message; it is expected to have a %s for the symbol name.  TO is
+// the existing symbol.  DEFINED/OBJECT is where the new symbol was
+// found.
+
+// FIXME: We should have better location information here.  When the
+// symbol is defined, we should be able to pull the location from the
+// debug info if there is any.
+
+void
+Symbol_table::report_resolve_problem(bool is_error, const char* msg,
+                                    const Symbol* to, Defined defined,
+                                    Object* object)
+{
+  std::string demangled(to->demangled_name());
+  size_t len = strlen(msg) + demangled.length() + 10;
+  char* buf = new char[len];
+  snprintf(buf, len, msg, demangled.c_str());
+
+  const char* objname;
+  switch (defined)
+    {
+    case OBJECT:
+      objname = object->name().c_str();
+      break;
+    case COPY:
+      objname = _("COPY reloc");
+      break;
+    case DEFSYM:
+    case UNDEFINED:
+      objname = _("command line");
+      break;
+    case SCRIPT:
+      objname = _("linker script");
+      break;
+    case PREDEFINED:
+      objname = _("linker defined");
+      break;
+    default:
+      gold_unreachable();
+    }
+
+  if (is_error)
+    gold_error("%s: %s", objname, buf);
+  else
+    gold_warning("%s: %s", objname, buf);
+
+  delete[] buf;
+
+  if (to->source() == Symbol::FROM_OBJECT)
+    objname = to->object()->name().c_str();
+  else
+    objname = _("command line");
+  gold_info("%s: %s: previous definition here", program_name, objname);
+}
+
 // A special case of should_override which is only called for a strong
 // defined symbol from a regular object file.  This is used when
 // defining special symbols.
 
 bool
-Symbol_table::should_override_with_special(const Symbol* to)
+Symbol_table::should_override_with_special(const Symbol* to, Defined defined)
 {
   bool adjust_common_sizes;
+  bool adjust_dyn_def;
   unsigned int frombits = global_flag | regular_flag | def_flag;
-  bool ret = Symbol_table::should_override(to, frombits, NULL,
-                                          &adjust_common_sizes);
-  gold_assert(!adjust_common_sizes);
+  bool ret = Symbol_table::should_override(to, frombits, defined, NULL,
+                                          &adjust_common_sizes,
+                                          &adjust_dyn_def);
+  gold_assert(!adjust_common_sizes && !adjust_dyn_def);
   return ret;
 }
 
@@ -757,9 +903,8 @@ Symbol::override_base_with_special(const Symbol* from)
 
   // We shouldn't see these flags.  If we do, we need to handle them
   // somehow.
-  gold_assert(!from->is_target_special_ || this->is_target_special_);
   gold_assert(!from->is_forwarder_);
-  gold_assert(!from->has_plt_offset_);
+  gold_assert(!from->has_plt_offset());
   gold_assert(!from->has_warning_);
   gold_assert(!from->is_copied_from_dynobj_);
   gold_assert(!from->is_forced_local_);
@@ -803,6 +948,7 @@ Symbol_table::override_with_special(Sized_symbol<size>* tosym,
       || ((tosym->visibility() == elfcpp::STV_HIDDEN
           || tosym->visibility() == elfcpp::STV_INTERNAL)
          && (tosym->binding() == elfcpp::STB_GLOBAL
+             || tosym->binding() == elfcpp::STB_GNU_UNIQUE
              || tosym->binding() == elfcpp::STB_WEAK)
          && !parameters->options().relocatable()))
     this->force_local(tosym);
@@ -812,7 +958,10 @@ Symbol_table::override_with_special(Sized_symbol<size>* tosym,
 // script to restrict this to only the ones needed for implemented
 // targets.
 
-#ifdef HAVE_TARGET_32_LITTLE
+// We have to instantiate both big and little endian versions because
+// these are used by other templates that depends on size only.
+
+#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
 template
 void
 Symbol_table::resolve<32, false>(
@@ -823,9 +972,7 @@ Symbol_table::resolve<32, false>(
     unsigned int orig_st_shndx,
     Object* object,
     const char* version);
-#endif
 
-#ifdef HAVE_TARGET_32_BIG
 template
 void
 Symbol_table::resolve<32, true>(
@@ -838,7 +985,7 @@ Symbol_table::resolve<32, true>(
     const char* version);
 #endif
 
-#ifdef HAVE_TARGET_64_LITTLE
+#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
 template
 void
 Symbol_table::resolve<64, false>(
@@ -849,9 +996,7 @@ Symbol_table::resolve<64, false>(
     unsigned int orig_st_shndx,
     Object* object,
     const char* version);
-#endif
 
-#ifdef HAVE_TARGET_64_BIG
 template
 void
 Symbol_table::resolve<64, true>(
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