const struct Version_dependency_list* dependencies;
};
+// Helper class that calls cplus_demangle when needed and takes care of freeing
+// the result.
+
+class Lazy_demangler
+{
+ public:
+ Lazy_demangler(const char* symbol, int options)
+ : symbol_(symbol), options_(options), demangled_(NULL), did_demangle_(false)
+ { }
+
+ ~Lazy_demangler()
+ { free(this->demangled_); }
+
+ // Return the demangled name. The actual demangling happens on the first call,
+ // and the result is later cached.
+ inline char*
+ get();
+
+ private:
+ // The symbol to demangle.
+ const char *symbol_;
+ // Option flags to pass to cplus_demagle.
+ const int options_;
+ // The cached demangled value, or NULL if demangling didn't happen yet or
+ // failed.
+ char *demangled_;
+ // Whether we already called cplus_demangle
+ bool did_demangle_;
+};
+
+// Return the demangled name. The actual demangling happens on the first call,
+// and the result is later cached. Returns NULL if the symbol cannot be
+// demangled.
+
+inline char*
+Lazy_demangler::get()
+{
+ if (!this->did_demangle_)
+ {
+ this->demangled_ = cplus_demangle(this->symbol_, this->options_);
+ this->did_demangle_ = true;
+ }
+ return this->demangled_;
+}
+
// Class Version_script_info.
Version_script_info::Version_script_info()
- : dependency_lists_(), expression_lists_(), version_trees_(),
- is_finalized_(false)
+ : dependency_lists_(), expression_lists_(), version_trees_(), globs_(),
+ default_version_(NULL), default_is_global_(false), is_finalized_(false)
{
for (int i = 0; i < LANGUAGE_COUNT; ++i)
- {
- this->globals_[i] = NULL;
- this->locals_[i] = NULL;
- }
+ this->exact_[i] = NULL;
}
Version_script_info::~Version_script_info()
return ret;
}
+// A version script essentially maps a symbol name to a version tag
+// and an indication of whether symbol is global or local within that
+// version tag. Each symbol maps to at most one version tag.
+// Unfortunately, in practice, version scripts are ambiguous, and list
+// symbols multiple times. Thus, we have to document the matching
+// process.
+
+// This is a description of what the GNU linker does as of 2010-01-11.
+// It walks through the version tags in the order in which they appear
+// in the version script. For each tag, it first walks through the
+// global patterns for that tag, then the local patterns. When
+// looking at a single pattern, it first applies any language specific
+// demangling as specified for the pattern, and then matches the
+// resulting symbol name to the pattern. If it finds an exact match
+// for a literal pattern (a pattern enclosed in quotes or with no
+// wildcard characters), then that is the match that it uses. If
+// finds a match with a wildcard pattern, then it saves it and
+// continues searching. Wildcard patterns that are exactly "*" are
+// saved separately.
+
+// If no exact match with a literal pattern is ever found, then if a
+// wildcard match with a global pattern was found it is used,
+// otherwise if a wildcard match with a local pattern was found it is
+// used.
+
+// This is the result:
+// * If there is an exact match, then we use the first tag in the
+// version script where it matches.
+// + If the exact match in that tag is global, it is used.
+// + Otherwise the exact match in that tag is local, and is used.
+// * Otherwise, if there is any match with a global wildcard pattern:
+// + If there is any match with a wildcard pattern which is not
+// "*", then we use the tag in which the *last* such pattern
+// appears.
+// + Otherwise, we matched "*". If there is no match with a local
+// wildcard pattern which is not "*", then we use the *last*
+// match with a global "*". Otherwise, continue.
+// * Otherwise, if there is any match with a local wildcard pattern:
+// + If there is any match with a wildcard pattern which is not
+// "*", then we use the tag in which the *last* such pattern
+// appears.
+// + Otherwise, we matched "*", and we use the tag in which the
+// *last* such match occurred.
+
+// There is an additional wrinkle. When the GNU linker finds a symbol
+// with a version defined in an object file due to a .symver
+// directive, it looks up that symbol name in that version tag. If it
+// finds it, it matches the symbol name against the patterns for that
+// version. If there is no match with a global pattern, but there is
+// a match with a local pattern, then the GNU linker marks the symbol
+// as local.
+
+// We want gold to be generally compatible, but we also want gold to
+// be fast. These are the rules that gold implements:
+// * If there is an exact match for the mangled name, we use it.
+// + If there is more than one exact match, we give a warning, and
+// we use the first tag in the script which matches.
+// + If a symbol has an exact match as both global and local for
+// the same version tag, we give an error.
+// * Otherwise, we look for an extern C++ or an extern Java exact
+// match. If we find an exact match, we use it.
+// + If there is more than one exact match, we give a warning, and
+// we use the first tag in the script which matches.
+// + If a symbol has an exact match as both global and local for
+// the same version tag, we give an error.
+// * Otherwise, we look through the wildcard patterns, ignoring "*"
+// patterns. We look through the version tags in reverse order.
+// For each version tag, we look through the global patterns and
+// then the local patterns. We use the first match we find (i.e.,
+// the last matching version tag in the file).
+// * Otherwise, we use the "*" pattern if there is one. We give an
+// error if there are multiple "*" patterns.
+
+// At least for now, gold does not look up the version tag for a
+// symbol version found in an object file to see if it should be
+// forced local. There are other ways to force a symbol to be local,
+// and I don't understand why this one is useful.
+
// Build a set of fast lookup tables for a version script.
void
for (size_t j = 0; j < size; ++j)
{
const Version_tree* v = this->version_trees_[j];
- this->build_expression_list_lookup(v->global, v, &this->globals_[0]);
- this->build_expression_list_lookup(v->local, v, &this->locals_[0]);
+ this->build_expression_list_lookup(v->local, v, false);
+ this->build_expression_list_lookup(v->global, v, true);
+ }
+}
+
+// If a pattern has backlashes but no unquoted wildcard characters,
+// then we apply backslash unquoting and look for an exact match.
+// Otherwise we treat it as a wildcard pattern. This function returns
+// true for a wildcard pattern. Otherwise, it does backslash
+// unquoting on *PATTERN and returns false. If this returns true,
+// *PATTERN may have been partially unquoted.
+
+bool
+Version_script_info::unquote(std::string* pattern) const
+{
+ bool saw_backslash = false;
+ size_t len = pattern->length();
+ size_t j = 0;
+ for (size_t i = 0; i < len; ++i)
+ {
+ if (saw_backslash)
+ saw_backslash = false;
+ else
+ {
+ switch ((*pattern)[i])
+ {
+ case '?': case '[': case '*':
+ return true;
+ case '\\':
+ saw_backslash = true;
+ continue;
+ default:
+ break;
+ }
+ }
+
+ if (i != j)
+ (*pattern)[j] = (*pattern)[i];
+ ++j;
+ }
+ return false;
+}
+
+// Add an exact match for MATCH to *PE. The result of the match is
+// V/IS_GLOBAL.
+
+void
+Version_script_info::add_exact_match(const std::string& match,
+ const Version_tree* v, bool is_global,
+ const Version_expression* ve,
+ Exact *pe)
+{
+ std::pair<Exact::iterator, bool> ins =
+ pe->insert(std::make_pair(match, Version_tree_match(v, is_global, ve)));
+ if (ins.second)
+ {
+ // This is the first time we have seen this match.
+ return;
+ }
+
+ Version_tree_match& vtm(ins.first->second);
+ if (vtm.real->tag != v->tag)
+ {
+ // This is an ambiguous match. We still return the
+ // first version that we found in the script, but we
+ // record the new version to issue a warning if we
+ // wind up looking up this symbol.
+ if (vtm.ambiguous == NULL)
+ vtm.ambiguous = v;
+ }
+ else if (is_global != vtm.is_global)
+ {
+ // We have a match for both the global and local entries for a
+ // version tag. That's got to be wrong.
+ gold_error(_("'%s' appears as both a global and a local symbol "
+ "for version '%s' in script"),
+ match.c_str(), v->tag.c_str());
}
}
// Build fast lookup information for EXPLIST and store it in LOOKUP.
+// All matches go to V, and IS_GLOBAL is true if they are global
+// matches.
void
Version_script_info::build_expression_list_lookup(
const Version_expression_list* explist,
const Version_tree* v,
- Lookup** lookup)
+ bool is_global)
{
if (explist == NULL)
return;
size_t size = explist->expressions.size();
- for (size_t j = 0; j < size; ++j)
+ for (size_t i = 0; i < size; ++i)
{
- const Version_expression& exp(explist->expressions[j]);
- Lookup **pp = &lookup[exp.language];
- if (*pp == NULL)
- *pp = new Lookup();
- Lookup* p = *pp;
-
- if (!exp.exact_match && strpbrk(exp.pattern.c_str(), "?*[") != NULL)
- p->globs.push_back(Glob(exp.pattern.c_str(), v));
- else
+ const Version_expression& exp(explist->expressions[i]);
+
+ if (exp.pattern.length() == 1 && exp.pattern[0] == '*')
+ {
+ if (this->default_version_ != NULL
+ && this->default_version_->tag != v->tag)
+ gold_error(_("wildcard match appears in both version '%s' "
+ "and '%s' in script"),
+ this->default_version_->tag.c_str(), v->tag.c_str());
+ else if (this->default_version_ != NULL
+ && this->default_is_global_ != is_global)
+ gold_error(_("wildcard match appears as both global and local "
+ "in version '%s' in script"),
+ v->tag.c_str());
+ this->default_version_ = v;
+ this->default_is_global_ = is_global;
+ continue;
+ }
+
+ std::string pattern = exp.pattern;
+ if (!exp.exact_match)
{
- std::pair<Exact::iterator, bool> ins =
- p->exact.insert(std::make_pair(exp.pattern, v));
- if (!ins.second)
+ if (this->unquote(&pattern))
{
- const Version_tree* v1 = ins.first->second;
- if (v1 != NULL && v1->tag != v->tag)
- {
- // This is an ambiguous match. It's OK if it's just
- // documenting symbol versions, but not if we look
- // up this symbol.
- ins.first->second = NULL;
- }
+ this->globs_.push_back(Glob(&exp, v, is_global));
+ continue;
}
}
+
+ if (this->exact_[exp.language] == NULL)
+ this->exact_[exp.language] = new Exact();
+ this->add_exact_match(pattern, v, is_global, &exp,
+ this->exact_[exp.language]);
}
}
-// Record that we have matched a name found in the version script.
+// Return the name to match given a name, a language code, and two
+// lazy demanglers.
-void
-Version_script_info::matched_symbol(const Version_tree* version_tree,
- const char* name) const
+const char*
+Version_script_info::get_name_to_match(const char* name,
+ int language,
+ Lazy_demangler* cpp_demangler,
+ Lazy_demangler* java_demangler) const
{
- const struct Version_expression_list* global = version_tree->global;
- for (size_t i = 0; i < global->expressions.size(); ++i)
+ switch (language)
{
- const Version_expression& expression(global->expressions[i]);
- if (expression.pattern == name
- && (expression.exact_match
- || strpbrk(expression.pattern.c_str(), "?*[") == NULL))
- {
- expression.was_matched_by_symbol = true;
- return;
- }
+ case LANGUAGE_C:
+ return name;
+ case LANGUAGE_CXX:
+ return cpp_demangler->get();
+ case LANGUAGE_JAVA:
+ return java_demangler->get();
+ default:
+ gold_unreachable();
}
- gold_unreachable();
}
-// Look up SYMBOL_NAME in the list of versions. If CHECK_GLOBAL is
-// true look at the globally visible symbols, otherwise look at the
-// symbols listed as "local:". Return true if the symbol is found,
-// false otherwise. If the symbol is found, then if PVERSION is not
-// NULL, set *PVERSION to the version.
+// Look up SYMBOL_NAME in the list of versions. Return true if the
+// symbol is found, false if not. If the symbol is found, then if
+// PVERSION is not NULL, set *PVERSION to the version tag, and if
+// P_IS_GLOBAL is not NULL, set *P_IS_GLOBAL according to whether the
+// symbol is global or not.
bool
-Version_script_info::get_symbol_version_helper(const char* symbol_name,
- bool check_global,
- std::string* pversion) const
+Version_script_info::get_symbol_version(const char* symbol_name,
+ std::string* pversion,
+ bool* p_is_global) const
{
+ Lazy_demangler cpp_demangled_name(symbol_name, DMGL_ANSI | DMGL_PARAMS);
+ Lazy_demangler java_demangled_name(symbol_name,
+ DMGL_ANSI | DMGL_PARAMS | DMGL_JAVA);
+
gold_assert(this->is_finalized_);
- const Lookup* const * pp = (check_global
- ? &this->globals_[0]
- : &this->locals_[0]);
for (int i = 0; i < LANGUAGE_COUNT; ++i)
{
- const Lookup* lookup = pp[i];
- if (lookup == NULL)
+ Exact* exact = this->exact_[i];
+ if (exact == NULL)
continue;
- const char* name_to_match;
- char* allocated;
- switch (i)
+ const char* name_to_match = this->get_name_to_match(symbol_name, i,
+ &cpp_demangled_name,
+ &java_demangled_name);
+ if (name_to_match == NULL)
{
- case LANGUAGE_C:
- allocated = NULL;
- name_to_match = symbol_name;
- break;
- case LANGUAGE_CXX:
- allocated = cplus_demangle(symbol_name, DMGL_ANSI | DMGL_PARAMS);
- if (allocated == NULL)
- continue;
- name_to_match = allocated;
- break;
- case LANGUAGE_JAVA:
- allocated = cplus_demangle(symbol_name,
- DMGL_ANSI | DMGL_PARAMS | DMGL_JAVA);
- if (allocated == NULL)
- continue;
- name_to_match = allocated;
- default:
- gold_unreachable();
+ // If the name can not be demangled, the GNU linker goes
+ // ahead and tries to match it anyhow. That does not
+ // make sense to me and I have not implemented it.
+ continue;
}
- Exact::const_iterator pe = lookup->exact.find(name_to_match);
- if (pe != lookup->exact.end())
+ Exact::const_iterator pe = exact->find(name_to_match);
+ if (pe != exact->end())
{
+ const Version_tree_match& vtm(pe->second);
+ if (vtm.ambiguous != NULL)
+ gold_warning(_("using '%s' as version for '%s' which is also "
+ "named in version '%s' in script"),
+ vtm.real->tag.c_str(), name_to_match,
+ vtm.ambiguous->tag.c_str());
+
if (pversion != NULL)
- {
- if (pe->second != NULL)
- *pversion = pe->second->tag;
- else
- {
- gold_error(_("'%s' has multiple versions in version script"),
- name_to_match);
- return false;
- }
- }
+ *pversion = vtm.real->tag;
+ if (p_is_global != NULL)
+ *p_is_global = vtm.is_global;
// If we are using --no-undefined-version, and this is a
// global symbol, we have to record that we have found this
// this now, because otherwise we have no way to get from a
// non-C language back to the demangled name that we
// matched.
- if (check_global && !parameters->options().undefined_version())
- this->matched_symbol(pe->second, name_to_match);
-
- if (allocated != NULL)
- free (allocated);
+ if (p_is_global != NULL && vtm.is_global)
+ vtm.expression->was_matched_by_symbol = true;
return true;
}
+ }
+
+ // Look through the glob patterns in reverse order.
+
+ for (Globs::const_reverse_iterator p = this->globs_.rbegin();
+ p != this->globs_.rend();
+ ++p)
+ {
+ int language = p->expression->language;
+ const char* name_to_match = this->get_name_to_match(symbol_name,
+ language,
+ &cpp_demangled_name,
+ &java_demangled_name);
+ if (name_to_match == NULL)
+ continue;
- for (std::vector<Glob>::const_iterator pg = lookup->globs.begin();
- pg != lookup->globs.end();
- ++pg)
+ if (fnmatch(p->expression->pattern.c_str(), name_to_match,
+ FNM_NOESCAPE) == 0)
{
- // Check for * specially since it is fairly common.
- if ((pg->pattern[0] == '*' && pg->pattern[1] == '\0')
- || fnmatch(pg->pattern, name_to_match, FNM_NOESCAPE) == 0)
- {
- if (pversion != NULL)
- *pversion = pg->version->tag;
- if (allocated != NULL)
- free (allocated);
- return true;
- }
+ if (pversion != NULL)
+ *pversion = p->version->tag;
+ if (p_is_global != NULL)
+ *p_is_global = p->is_global;
+ return true;
}
+ }
- if (allocated != NULL)
- free (allocated);
+ // Finally, there may be a wildcard.
+ if (this->default_version_ != NULL)
+ {
+ if (pversion != NULL)
+ *pversion = this->default_version_->tag;
+ if (p_is_global != NULL)
+ *p_is_global = this->default_is_global_;
+ return true;
}
return false;
if (expression.language != LANGUAGE_C)
continue;
- // Ignore wildcard patterns.
- if (!expression.exact_match
- && strpbrk(expression.pattern.c_str(), "?*[") != NULL)
- continue;
-
- if (symtab->lookup(expression.pattern.c_str(),
- vt->tag.c_str()) == NULL)
+ // Remove backslash quoting, and ignore wildcard patterns.
+ std::string pattern = expression.pattern;
+ if (!expression.exact_match)
{
- gold_error(_("version script assignment of %s to symbol %s "
- "failed: symbol not defined"),
- vt->tag.c_str(), expression.pattern.c_str());
+ if (this->unquote(&pattern))
+ continue;
}
+
+ if (symtab->lookup(pattern.c_str(), vt->tag.c_str()) == NULL)
+ gold_error(_("version script assignment of %s to symbol %s "
+ "failed: symbol not defined"),
+ vt->tag.c_str(), pattern.c_str());
}
}
}
struct Version_dependency_list;
struct Version_expression_list;
struct Version_tree;
+struct Version_expression;
+class Lazy_demangler;
// This class represents an expression in a linker script.
{ return this->version_trees_.empty(); }
// If there is a version associated with SYMBOL, return true, and
- // set *VERSION to the version. Otherwise, return false.
+ // set *VERSION to the version, and *IS_GLOBAL to whether the symbol
+ // should be global. Otherwise, return false.
bool
- get_symbol_version(const char* symbol, std::string* version) const
- { return this->get_symbol_version_helper(symbol, true, version); }
+ get_symbol_version(const char* symbol, std::string* version,
+ bool* is_global) const;
// Return whether this symbol matches the local: section of some
// version.
bool
symbol_is_local(const char* symbol) const
- { return this->get_symbol_version_helper(symbol, false, NULL); }
+ {
+ bool is_global;
+ return (this->get_symbol_version(symbol, NULL, &is_global)
+ && !is_global);
+ }
// Return the names of versions defined in the version script.
std::vector<std::string>
bool check_global,
std::string* pversion) const;
- void
- matched_symbol(const Version_tree*, const char*) const;
+ // Fast lookup information for a given language.
+
+ // We map from exact match strings to Version_tree's. Historically
+ // version scripts sometimes have the same symbol multiple times,
+ // which is ambiguous. We warn about that case by storing the
+ // second Version_tree we see.
+ struct Version_tree_match
+ {
+ Version_tree_match(const Version_tree* r, bool ig,
+ const Version_expression* e)
+ : real(r), is_global(ig), expression(e), ambiguous(NULL)
+ { }
+
+ // The Version_tree that we return.
+ const Version_tree* real;
+ // True if this is a global match for the REAL member, false if it
+ // is a local match.
+ bool is_global;
+ // Point back to the Version_expression for which we created this
+ // match.
+ const Version_expression* expression;
+ // If not NULL, another Version_tree that defines the symbol.
+ const Version_tree* ambiguous;
+ };
+
+ // Map from an exact match string to a Version_tree.
+
+ typedef Unordered_map<std::string, Version_tree_match> Exact;
// Fast lookup information for a glob pattern.
struct Glob
{
Glob()
- : pattern(NULL), version(NULL)
+ : expression(NULL), version(NULL), is_global(false)
{ }
- Glob(const char* p, const Version_tree* v)
- : pattern(p), version(v)
+ Glob(const Version_expression* e, const Version_tree* v, bool ig)
+ : expression(e), version(v), is_global(ig)
{ }
- // A pointer to the glob pattern. The pattern itself lives in a
- // Version_expression structure.
- const char* pattern;
+ // A pointer to the version expression holding the pattern to
+ // match and the language to use for demangling the symbol before
+ // doing the match.
+ const Version_expression* expression;
// The Version_tree we use if this pattern matches.
const Version_tree* version;
+ // True if this is a global symbol.
+ bool is_global;
};
- // Fast lookup information for a given language.
+ typedef std::vector<Glob> Globs;
- typedef Unordered_map<std::string, const Version_tree*> Exact;
+ bool
+ unquote(std::string*) const;
- struct Lookup
- {
- // A hash table of all exact match strings mapping to a
- // Version_tree.
- Exact exact;
- // A vector of glob patterns mapping to Version_trees.
- std::vector<Glob> globs;
- };
+ void
+ add_exact_match(const std::string&, const Version_tree*, bool is_global,
+ const Version_expression*, Exact*);
void
build_expression_list_lookup(const Version_expression_list*,
- const Version_tree*, Lookup**);
+ const Version_tree*, bool);
+
+ const char*
+ get_name_to_match(const char*, int,
+ Lazy_demangler*, Lazy_demangler*) const;
// All the version dependencies we allocate.
std::vector<Version_dependency_list*> dependency_lists_;
std::vector<Version_expression_list*> expression_lists_;
// The list of versions.
std::vector<Version_tree*> version_trees_;
- // Lookup information for global symbols, by language.
- Lookup* globals_[LANGUAGE_COUNT];
- // Lookup information for local symbols, by language.
- Lookup* locals_[LANGUAGE_COUNT];
+ // Exact matches for global symbols, by language.
+ Exact* exact_[LANGUAGE_COUNT];
+ // A vector of glob patterns mapping to Version_trees.
+ Globs globs_;
+ // The default version to use, if there is one. This is from a
+ // pattern of "*".
+ const Version_tree* default_version_;
+ // True if the default version is global.
+ bool default_is_global_;
// Whether this has been finalized.
bool is_finalized_;
};
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