(*input_objects->dynobj_begin())->name().c_str());
}
+ // See if any of the input definitions violate the One Definition Rule.
+ // TODO: if this is too slow, do this as a task, rather than inline.
+ symtab->detect_odr_violations();
+
// Define some sections and symbols needed for a dynamic link. This
// handles some cases we want to see before we read the relocs.
layout->create_initial_dynamic_sections(input_objects, symtab);
static const unsigned int undef_flag = 1 << def_undef_or_common_shift;
static const unsigned int common_flag = 2 << def_undef_or_common_shift;
+// This convenience function combines all the flags based on facts
+// about the symbol.
+
+static unsigned int
+symbol_to_bits(elfcpp::STB binding, bool is_dynamic,
+ unsigned int shndx, elfcpp::STT type)
+{
+ unsigned int bits;
+
+ switch (binding)
+ {
+ case elfcpp::STB_GLOBAL:
+ bits = global_flag;
+ break;
+
+ case elfcpp::STB_WEAK:
+ bits = weak_flag;
+ break;
+
+ case elfcpp::STB_LOCAL:
+ // We should only see externally visible symbols in the symbol
+ // table.
+ gold_error(_("invalid STB_LOCAL symbol in external symbols"));
+ bits = global_flag;
+
+ default:
+ // Any target which wants to handle STB_LOOS, etc., needs to
+ // define a resolve method.
+ gold_error(_("unsupported symbol binding"));
+ bits = global_flag;
+ }
+
+ if (is_dynamic)
+ bits |= dynamic_flag;
+ else
+ bits |= regular_flag;
+
+ switch (shndx)
+ {
+ case elfcpp::SHN_UNDEF:
+ bits |= undef_flag;
+ break;
+
+ case elfcpp::SHN_COMMON:
+ bits |= common_flag;
+ break;
+
+ default:
+ if (type == elfcpp::STT_COMMON)
+ bits |= common_flag;
+ else
+ bits |= def_flag;
+ break;
+ }
+
+ return bits;
+}
+
// Resolve a symbol. This is called the second and subsequent times
-// we see a symbol. TO is the pre-existing symbol. SYM is the new
-// symbol, seen in OBJECT. VERSION of the version of SYM.
+// we see a symbol. TO is the pre-existing symbol. ORIG_SYM is the
+// new symbol, seen in OBJECT. SYM is almost always identical to
+// ORIG_SYM, but may be munged (for instance, if we determine the
+// symbol is in a to-be-discarded section, we'll set sym's shndx to
+// UNDEFINED). VERSION of the version of SYM.
template<int size, bool big_endian>
void
Symbol_table::resolve(Sized_symbol<size>* to,
const elfcpp::Sym<size, big_endian>& sym,
+ const elfcpp::Sym<size, big_endian>& orig_sym,
Object* object, const char* version)
{
if (object->target()->has_resolve())
to->set_in_dyn();
}
- unsigned int frombits;
- switch (sym.get_st_bind())
- {
- case elfcpp::STB_GLOBAL:
- frombits = global_flag;
- break;
-
- case elfcpp::STB_WEAK:
- frombits = weak_flag;
- break;
-
- case elfcpp::STB_LOCAL:
- gold_error(_("%s: invalid STB_LOCAL symbol %s in external symbols"),
- object->name().c_str(), to->name());
- frombits = global_flag;
- break;
-
- default:
- gold_error(_("%s: unsupported symbol binding %d for symbol %s"),
- object->name().c_str(),
- static_cast<int>(sym.get_st_bind()), to->name());
- frombits = global_flag;
- break;
- }
-
- if (!object->is_dynamic())
- frombits |= regular_flag;
- else
- frombits |= dynamic_flag;
-
- switch (sym.get_st_shndx())
- {
- case elfcpp::SHN_UNDEF:
- frombits |= undef_flag;
- break;
-
- case elfcpp::SHN_COMMON:
- frombits |= common_flag;
- break;
-
- default:
- if (sym.get_st_type() == elfcpp::STT_COMMON)
- frombits |= common_flag;
- else
- frombits |= def_flag;
- break;
- }
+ unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
+ object->is_dynamic(),
+ sym.get_st_shndx(),
+ sym.get_st_type());
bool adjust_common_sizes;
if (Symbol_table::should_override(to, frombits, object,
if (adjust_common_sizes && sym.get_st_size() > to->symsize())
to->set_symsize(sym.get_st_size());
}
+
+ // 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.)
+ // We use orig_sym here because we want the symbol exactly as it
+ // appears in the object file, not munged via our future processing.
+ if (orig_sym.get_st_bind() == elfcpp::STB_WEAK
+ && to->binding() == elfcpp::STB_WEAK
+ && orig_sym.get_st_shndx() != elfcpp::SHN_UNDEF
+ && to->shndx() != elfcpp::SHN_UNDEF
+ && orig_sym.get_st_size() != 0 // Ignore weird 0-sized symbols.
+ && to->symsize() != 0
+ && (orig_sym.get_st_type() != to->type()
+ || orig_sym.get_st_size() != to->symsize())
+ // C does not have a concept of ODR, so we only need to do this
+ // on C++ symbols. These have (mangled) names starting with _Z.
+ && to->name()[0] == '_' && to->name()[1] == 'Z')
+ {
+ Symbol_location from_location
+ = { object, orig_sym.get_st_shndx(), orig_sym.get_st_value() };
+ Symbol_location to_location = { to->object(), to->shndx(), to->value() };
+ this->candidate_odr_violations_[to->name()].insert(from_location);
+ this->candidate_odr_violations_[to->name()].insert(to_location);
+ }
}
// Handle the core of symbol resolution. This is called with the
{
*adjust_common_sizes = false;
- unsigned int tobits;
- switch (to->binding())
- {
- case elfcpp::STB_GLOBAL:
- tobits = global_flag;
- break;
-
- case elfcpp::STB_WEAK:
- tobits = weak_flag;
- break;
-
- case elfcpp::STB_LOCAL:
- // We should only see externally visible symbols in the symbol
- // table.
- gold_unreachable();
-
- default:
- // Any target which wants to handle STB_LOOS, etc., needs to
- // define a resolve method.
- gold_unreachable();
- }
-
- if (to->source() == Symbol::FROM_OBJECT
- && to->object()->is_dynamic())
- tobits |= dynamic_flag;
- else
- tobits |= regular_flag;
-
- switch (to->shndx())
- {
- case elfcpp::SHN_UNDEF:
- tobits |= undef_flag;
- break;
-
- case elfcpp::SHN_COMMON:
- tobits |= common_flag;
- break;
-
- default:
- if (to->type() == elfcpp::STT_COMMON)
- tobits |= common_flag;
- else
- tobits |= def_flag;
- break;
- }
+ unsigned int tobits = symbol_to_bits(to->binding(),
+ (to->source() == Symbol::FROM_OBJECT
+ && to->object()->is_dynamic()),
+ to->shndx(),
+ to->type());
// FIXME: Warn if either but not both of TO and SYM are STT_TLS.
Symbol_table::resolve<32, false>(
Sized_symbol<32>* to,
const elfcpp::Sym<32, false>& sym,
+ const elfcpp::Sym<32, false>& orig_sym,
Object* object,
const char* version);
#endif
Symbol_table::resolve<32, true>(
Sized_symbol<32>* to,
const elfcpp::Sym<32, true>& sym,
+ const elfcpp::Sym<32, true>& orig_sym,
Object* object,
const char* version);
#endif
Symbol_table::resolve<64, false>(
Sized_symbol<64>* to,
const elfcpp::Sym<64, false>& sym,
+ const elfcpp::Sym<64, false>& orig_sym,
Object* object,
const char* version);
#endif
Symbol_table::resolve<64, true>(
Sized_symbol<64>* to,
const elfcpp::Sym<64, true>& sym,
+ const elfcpp::Sym<64, true>& orig_sym,
Object* object,
const char* version);
#endif
#include "gold.h"
#include <stdint.h>
+#include <set>
#include <string>
#include <utility>
#include "object.h"
+#include "dwarf_reader.h"
#include "dynobj.h"
#include "output.h"
#include "target.h"
esym.put_st_info(from->binding(), from->type());
esym.put_st_other(from->visibility(), from->nonvis());
esym.put_st_shndx(from->shndx());
- this->resolve(to, esym.sym(), from->object(), version);
+ this->resolve(to, esym.sym(), esym.sym(), from->object(), version);
if (from->in_reg())
to->set_in_reg();
if (from->in_dyn())
// object file as a forwarder, and record it in the forwarders_ map.
// Note that entries in the hash table will never be marked as
// forwarders.
+//
+// SYM and ORIG_SYM are almost always the same. ORIG_SYM is the
+// symbol exactly as it existed in the input file. SYM is usually
+// that as well, but can be modified, for instance if we determine
+// it's in a to-be-discarded section.
template<int size, bool big_endian>
Sized_symbol<size>*
const char *version,
Stringpool::Key version_key,
bool def,
- const elfcpp::Sym<size, big_endian>& sym)
+ const elfcpp::Sym<size, big_endian>& sym,
+ const elfcpp::Sym<size, big_endian>& orig_sym)
{
Symbol* const snull = NULL;
std::pair<typename Symbol_table_type::iterator, bool> ins =
was_undefined = ret->is_undefined();
was_common = ret->is_common();
- this->resolve(ret, sym, object, version);
+ this->resolve(ret, sym, orig_sym, object, version);
if (def)
{
ret = this->get_sized_symbol SELECT_SIZE_NAME(size) (
insdef.first->second
SELECT_SIZE(size));
- this->resolve(ret, sym, object, version);
+ this->resolve(ret, sym, orig_sym, object, version);
ins.first->second = ret;
}
else
Stringpool::Key name_key;
name = this->namepool_.add(name, true, &name_key);
res = this->add_from_object(relobj, name, name_key, NULL, 0,
- false, *psym);
+ false, *psym, sym);
}
else
{
ver = this->namepool_.add(ver, true, &ver_key);
res = this->add_from_object(relobj, name, name_key, ver, ver_key,
- def, *psym);
+ def, *psym, sym);
}
(*sympointers)[i] = res;
Stringpool::Key name_key;
name = this->namepool_.add(name, true, &name_key);
res = this->add_from_object(dynobj, name, name_key, NULL, 0,
- false, sym);
+ false, sym, sym);
}
else
{
{
// This symbol does not have a version.
res = this->add_from_object(dynobj, name, name_key, NULL, 0,
- false, sym);
+ false, sym, sym);
}
else
{
if (sym.get_st_shndx() == elfcpp::SHN_ABS
&& name_key == version_key)
res = this->add_from_object(dynobj, name, name_key, NULL, 0,
- false, sym);
+ false, sym, sym);
else
{
const bool def = (!hidden
&& (sym.get_st_shndx()
!= elfcpp::SHN_UNDEF));
res = this->add_from_object(dynobj, name, name_key, version,
- version_key, def, sym);
+ version_key, def, sym, sym);
}
}
}
of->write_output_view(offset, sym_size, pov);
}
+// Check candidate_odr_violations_ to find symbols with the same name
+// but apparently different definitions (different source-file/line-no).
+
+void
+Symbol_table::detect_odr_violations() const
+{
+ if (parameters->get_size() == 32)
+ {
+ if (!parameters->is_big_endian())
+ {
+#ifdef HAVE_TARGET_32_LITTLE
+ this->sized_detect_odr_violations<32, false>();
+#else
+ gold_unreachable();
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_32_BIG
+ this->sized_detect_odr_violations<32, true>();
+#else
+ gold_unreachable();
+#endif
+ }
+ }
+ else if (parameters->get_size() == 64)
+ {
+ if (!parameters->is_big_endian())
+ {
+#ifdef HAVE_TARGET_64_LITTLE
+ this->sized_detect_odr_violations<64, false>();
+#else
+ gold_unreachable();
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_64_BIG
+ this->sized_detect_odr_violations<64, true>();
+#else
+ gold_unreachable();
+#endif
+ }
+ }
+ else
+ gold_unreachable();
+}
+
+// Implement detect_odr_violations.
+
+template<int size, bool big_endian>
+void
+Symbol_table::sized_detect_odr_violations() const
+{
+ for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
+ it != candidate_odr_violations_.end();
+ ++it)
+ {
+ const char* symbol_name = it->first;
+ // We use a sorted set so the output is deterministic.
+ std::set<std::string> line_nums;
+
+ Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
+ locs;
+ for (locs = it->second.begin(); locs != it->second.end(); ++locs)
+ {
+ // We need to lock the object in order to read it. This
+ // means that we can not run inside a Task. If we want to
+ // run this in a Task for better performance, we will need
+ // one Task for object, plus appropriate locking to ensure
+ // that we don't conflict with other uses of the object.
+ locs->object->lock();
+ Dwarf_line_info<size, big_endian> line_info(locs->object);
+ locs->object->unlock();
+ std::string lineno = line_info.addr2line(locs->shndx, locs->offset);
+ if (!lineno.empty())
+ line_nums.insert(lineno);
+ }
+
+ if (line_nums.size() > 1)
+ {
+ gold_warning(_("symbol %s defined in multiple places "
+ "(possible ODR violation):"), symbol_name);
+ for (std::set<std::string>::const_iterator it2 = line_nums.begin();
+ it2 != line_nums.end();
+ ++it2)
+ fprintf(stderr, " %s\n", it2->c_str());
+ }
+ }
+}
+
// Warnings functions.
// Add a new warning.
};
// A mapping from warning symbol names (canonicalized in
- // Symbol_table's namepool_ field) to
+ // Symbol_table's namepool_ field) to warning information.
typedef Unordered_map<const char*, Warning_location> Warning_table;
Warning_table warnings_;
// Define a set of symbols in output segments.
void
define_symbols(const Layout*, const Target*, int count,
- const Define_symbol_in_segment*);
+ const Define_symbol_in_segment*);
// Define SYM using a COPY reloc. POSD is the Output_data where the
// symbol should be defined--typically a .dyn.bss section. VALUE is
size_t relnum, off_t reloffset) const
{ this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); }
+ // Check candidate_odr_violations_ to find symbols with the same name
+ // but apparently different definitions (different source-file/line-no).
+ void
+ detect_odr_violations() const;
+
// SYM is defined using a COPY reloc. Return the dynamic object
// where the original definition was found.
Dynobj*
Sized_symbol<size>*
add_from_object(Object*, const char *name, Stringpool::Key name_key,
const char *version, Stringpool::Key version_key,
- bool def, const elfcpp::Sym<size, big_endian>& sym);
+ bool def, const elfcpp::Sym<size, big_endian>& sym,
+ const elfcpp::Sym<size, big_endian>& orig_sym);
// Resolve symbols.
template<int size, bool big_endian>
void
resolve(Sized_symbol<size>* to,
const elfcpp::Sym<size, big_endian>& sym,
+ const elfcpp::Sym<size, big_endian>& orig_sym,
Object*, const char* version);
template<int size, bool big_endian>
void
do_allocate_commons(const General_options&, Layout*);
+ // Implement detect_odr_violations.
+ template<int size, bool big_endian>
+ void
+ sized_detect_odr_violations() const;
+
// Finalize symbols specialized for size.
template<int size>
off_t
// they are defined.
typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs;
+ // A map from symbol name (as a pointer into the namepool) to all
+ // the locations the symbols is (weakly) defined (and certain other
+ // conditions are met). This map will be used later to detect
+ // possible One Definition Rule (ODR) violations.
+ struct Symbol_location
+ {
+ Object* object; // Object where the symbol is defined.
+ unsigned int shndx; // Section-in-object where the symbol is defined.
+ off_t offset; // Offset-in-section where the symbol is defined.
+ bool operator==(const Symbol_location& that) const
+ {
+ return (this->object == that.object
+ && this->shndx == that.shndx
+ && this->offset == that.offset);
+ }
+ };
+
+ struct Symbol_location_hash
+ {
+ size_t operator()(const Symbol_location& loc) const
+ { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
+ };
+
+ typedef Unordered_map<const char*,
+ Unordered_set<Symbol_location, Symbol_location_hash> >
+ Odr_map;
+
// We increment this every time we see a new undefined symbol, for
// use in archive groups.
int saw_undefined_;
Commons_type commons_;
// Manage symbol warnings.
Warnings warnings_;
+ // Manage potential One Definition Rule (ODR) violations.
+ Odr_map candidate_odr_violations_;
+
// When we emit a COPY reloc for a symbol, we define it in an
// Output_data. When it's time to emit version information for it,
// we need to know the dynamic object in which we found the original
projects / deliverable / binutils-gdb.git / commitdiff
