From f0641a0b382db7403f04fab3d4e8fac25a2b68af Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Tue, 7 Nov 2006 04:40:46 +0000 Subject: [PATCH] Rework stringpool and hash tables so that we always generate the same output regardless of randomize_va_space. --- gold/layout.cc | 27 ++++++++++-------- gold/layout.h | 6 ++-- gold/object.cc | 2 +- gold/po/gold.pot | 10 +++---- gold/stringpool.cc | 69 ++++++++++++++++++++++++++++++++++------------ gold/stringpool.h | 51 ++++++++++++++++++++++++---------- gold/symtab.cc | 55 +++++++++++++++++++++++------------- gold/symtab.h | 10 +++---- 8 files changed, 152 insertions(+), 78 deletions(-) diff --git a/gold/layout.cc b/gold/layout.cc index 2bdd11b4772..e969a806a08 100644 --- a/gold/layout.cc +++ b/gold/layout.cc @@ -53,7 +53,7 @@ Layout::Layout(const General_options& options) size_t Layout::Hash_key::operator()(const Layout::Key& k) const { - return reinterpret_cast(k.first) + k.second.first + k.second.second; + return k.first + k.second.first + k.second.second; } // Whether to include this section in the link. @@ -95,7 +95,7 @@ Layout::find_output_section(const char* name) const for (Section_name_map::const_iterator p = this->section_name_map_.begin(); p != this->section_name_map_.end(); ++p) - if (strcmp(p->first.first, name) == 0) + if (strcmp(p->second->name(), name) == 0) return p->second; return NULL; } @@ -121,15 +121,15 @@ Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, // and section flags FLAGS. Output_section* -Layout::get_output_section(const char* name, elfcpp::Elf_Word type, - elfcpp::Elf_Xword flags) +Layout::get_output_section(const char* name, Stringpool::Key name_key, + elfcpp::Elf_Word type, elfcpp::Elf_Xword flags) { // We should ignore some flags. flags &= ~ (elfcpp::SHF_INFO_LINK | elfcpp::SHF_LINK_ORDER | elfcpp::SHF_GROUP); - const Key key(name, std::make_pair(type, flags)); + const Key key(name_key, std::make_pair(type, flags)); const std::pair v(key, NULL); std::pair ins( this->section_name_map_.insert(v)); @@ -167,11 +167,13 @@ Layout::layout(Relobj* object, unsigned int shndx, const char* name, // FIXME: Handle SHF_OS_NONCONFORMING here. // Canonicalize the section name. - name = this->namepool_.add(name, len); + Stringpool::Key name_key; + name = this->namepool_.add(name, len, &name_key); // Find the output section. The output section is selected based on // the section name, type, and flags. - Output_section* os = this->get_output_section(name, shdr.get_sh_type(), + Output_section* os = this->get_output_section(name, name_key, + shdr.get_sh_type(), shdr.get_sh_flags()); // FIXME: Handle SHF_LINK_ORDER somewhere. @@ -189,9 +191,10 @@ Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type, Output_section_data* posd) { // Canonicalize the name. - name = this->namepool_.add(name); + Stringpool::Key name_key; + name = this->namepool_.add(name, &name_key); - Output_section* os = this->get_output_section(name, type, flags); + Output_section* os = this->get_output_section(name, name_key, type, flags); os->add_output_section_data(posd); } @@ -672,12 +675,12 @@ Layout::create_symtab_sections(int size, const Input_objects* input_objects, this->sympool_.set_string_offsets(); - const char* symtab_name = this->namepool_.add(".symtab"); + const char* symtab_name = this->namepool_.add(".symtab", NULL); Output_section* osymtab = new Output_section_symtab(symtab_name, off - startoff); this->section_list_.push_back(osymtab); - const char* strtab_name = this->namepool_.add(".strtab"); + const char* strtab_name = this->namepool_.add(".strtab", NULL); Output_section *ostrtab = new Output_section_strtab(strtab_name, &this->sympool_); this->section_list_.push_back(ostrtab); @@ -703,7 +706,7 @@ Layout::create_shstrtab() // FIXME: We don't need to create a .shstrtab section if we are // stripping everything. - const char* name = this->namepool_.add(".shstrtab"); + const char* name = this->namepool_.add(".shstrtab", NULL); this->namepool_.set_string_offsets(); diff --git a/gold/layout.h b/gold/layout.h index bb2b644bd65..fa34617a3be 100644 --- a/gold/layout.h +++ b/gold/layout.h @@ -196,8 +196,8 @@ class Layout // Return the output section for NAME, TYPE and FLAGS. Output_section* - get_output_section(const char* name, elfcpp::Elf_Word type, - elfcpp::Elf_Xword flags); + get_output_section(const char* name, Stringpool::Key name_key, + elfcpp::Elf_Word type, elfcpp::Elf_Xword flags); // Create a new Output_section. Output_section* @@ -218,7 +218,7 @@ class Layout // Mapping from input section name/type/flags to output section. We // use canonicalized strings here. - typedef std::pair > Key; struct Hash_key diff --git a/gold/object.cc b/gold/object.cc index 22e89a9604a..956366cdf0a 100644 --- a/gold/object.cc +++ b/gold/object.cc @@ -628,7 +628,7 @@ Sized_relobj::do_finalize_local_symbols(off_t off, if (sym.get_st_type() != elfcpp::STT_SECTION) { - pool->add(pnames + sym.get_st_name()); + pool->add(pnames + sym.get_st_name(), NULL); off += sym_size; ++count; } diff --git a/gold/po/gold.pot b/gold/po/gold.pot index 4f00da433c0..c88ba7dd7fb 100644 --- a/gold/po/gold.pot +++ b/gold/po/gold.pot @@ -8,7 +8,7 @@ msgid "" msgstr "" "Project-Id-Version: PACKAGE VERSION\n" "Report-Msgid-Bugs-To: \n" -"POT-Creation-Date: 2006-11-06 13:40-0800\n" +"POT-Creation-Date: 2006-11-06 15:58-0800\n" "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n" "Last-Translator: FULL NAME \n" "Language-Team: LANGUAGE \n" @@ -477,22 +477,22 @@ msgstr "" msgid "%s: %s: unsupported symbol binding %d for symbol %s\n" msgstr "" -#: symtab.cc:432 +#: symtab.cc:440 #, c-format msgid "%s: %s: mixing 32-bit and 64-bit ELF objects\n" msgstr "" -#: symtab.cc:449 +#: symtab.cc:457 #, c-format msgid "%s: %s: bad global symbol name offset %u at %lu\n" msgstr "" -#: symtab.cc:865 symtab.cc:1004 +#: symtab.cc:882 symtab.cc:1021 #, c-format msgid "%s: %s: unsupported symbol section 0x%x\n" msgstr "" -#: symtab.cc:1114 +#: symtab.cc:1131 #, c-format msgid "%s: %s: warning: %s\n" msgstr "" diff --git a/gold/stringpool.cc b/gold/stringpool.cc index b1a2ce24336..5b60259a208 100644 --- a/gold/stringpool.cc +++ b/gold/stringpool.cc @@ -14,7 +14,7 @@ namespace gold { Stringpool::Stringpool() - : string_set_(), strings_(), strtab_size_(0) + : string_set_(), strings_(), strtab_size_(0), next_index_(1) { } @@ -55,12 +55,18 @@ Stringpool::Stringpool_hash::operator()(const char* s) const } // Add a string to the list of canonical strings. Return a pointer to -// the canonical string. +// the canonical string. If PKEY is not NULL, set *PKEY to the key. const char* -Stringpool::add_string(const char* s) +Stringpool::add_string(const char* s, Key* pkey) { + // The size we allocate for a new Stringdata. const size_t buffer_size = 1000; + // The amount we multiply the Stringdata index when calculating the + // key. + const size_t key_mult = 1024; + assert(key_mult >= buffer_size); + size_t len = strlen(s); size_t alc; @@ -81,7 +87,12 @@ Stringpool::add_string(const char* s) { char* ret = psd->data + psd->len; memcpy(ret, s, len + 1); + + if (pkey != NULL) + *pkey = psd->index * key_mult + psd->len; + psd->len += len + 1; + return ret; } } @@ -90,17 +101,24 @@ Stringpool::add_string(const char* s) psd->alc = alc - sizeof(Stringdata); memcpy(psd->data, s, len + 1); psd->len = len + 1; + psd->index = this->next_index_; + ++this->next_index_; + + if (pkey != NULL) + *pkey = psd->index * key_mult; + if (front) this->strings_.push_front(psd); else this->strings_.push_back(psd); + return psd->data; } // Add a string to a string pool. const char* -Stringpool::add(const char* s) +Stringpool::add(const char* s, Key* pkey) { // FIXME: This will look up the entry twice in the hash table. The // problem is that we can't insert S before we canonicalize it. I @@ -110,33 +128,48 @@ Stringpool::add(const char* s) String_set_type::const_iterator p = this->string_set_.find(s); if (p != this->string_set_.end()) - return p->first; + { + if (pkey != NULL) + *pkey = p->second.first; + return p->first; + } - const char* ret = this->add_string(s); - std::pair val(ret, 0); + Key k; + const char* ret = this->add_string(s, &k); + + const off_t ozero = 0; + std::pair element(ret, std::make_pair(k, ozero)); std::pair ins = - this->string_set_.insert(val); + this->string_set_.insert(element); assert(ins.second); + + if (pkey != NULL) + *pkey = k; + return ret; } // Add a prefix of a string to a string pool. const char* -Stringpool::add(const char* s, size_t len) +Stringpool::add(const char* s, size_t len, Key* pkey) { // FIXME: This implementation should be rewritten when we rewrite // the hash table to avoid copying. std::string st(s, len); - return this->add(st); + return this->add(st, pkey); } const char* -Stringpool::find(const char* s) const +Stringpool::find(const char* s, Key* pkey) const { String_set_type::const_iterator p = this->string_set_.find(s); if (p == this->string_set_.end()) return NULL; + + if (pkey != NULL) + *pkey = p->second.first; + return p->first; } @@ -206,14 +239,14 @@ Stringpool::set_string_offsets() for (size_t i = 0; i < count; ++i) { if (v[i]->first[0] == '\0') - v[i]->second = 0; + v[i]->second.second = 0; else if (i > 0 && Stringpool::is_suffix(v[i]->first, v[i - 1]->first)) - v[i]->second = (v[i - 1]->second - + strlen(v[i - 1]->first) - - strlen(v[i]->first)); + v[i]->second.second = (v[i - 1]->second.second + + strlen(v[i - 1]->first) + - strlen(v[i]->first)); else { - v[i]->second = offset; + v[i]->second.second = offset; offset += strlen(v[i]->first) + 1; } } @@ -229,7 +262,7 @@ Stringpool::get_offset(const char* s) const { String_set_type::const_iterator p = this->string_set_.find(s); if (p != this->string_set_.end()) - return p->second; + return p->second.second; abort(); } @@ -244,7 +277,7 @@ Stringpool::write(Output_file* of, off_t offset) for (String_set_type::const_iterator p = this->string_set_.begin(); p != this->string_set_.end(); ++p) - strcpy(view + p->second, p->first); + strcpy(view + p->second.second, p->first); of->write_output_view(offset, this->strtab_size_, viewu); } diff --git a/gold/stringpool.h b/gold/stringpool.h index 01c71a13553..ed549b48905 100644 --- a/gold/stringpool.h +++ b/gold/stringpool.h @@ -17,34 +17,42 @@ class Output_file; class Stringpool { public: + // The type of a key into the stringpool. A key value will always + // be the same during any run of the linker. The string pointers + // may change when using address space randomization. We use key + // values in order to get repeatable runs when the value is inserted + // into an unordered hash table. Zero is never a valid key. + typedef size_t Key; + Stringpool(); ~Stringpool(); // Add a string to the pool. This returns a canonical permanent - // pointer to the string. + // pointer to the string. If PKEY is not NULL, this sets *PKEY to + // the key for the string. const char* - add(const char*); + add(const char*, Key* pkey); const char* - add(const std::string& s) - { return this->add(s.c_str()); } + add(const std::string& s, Key* pkey) + { return this->add(s.c_str(), pkey); } // Add the prefix of a string to the pool. const char* - add(const char *, size_t); + add(const char *, size_t, Key* pkey); // If a string is present, return the canonical string. Otherwise, - // return NULL. + // return NULL. If PKEY is not NULL, set *PKEY to the key. const char* - find(const char*) const; + find(const char*, Key* pkey) const; // Turn the stringpool into an ELF strtab: determine the offsets of // all the strings. void set_string_offsets(); - // Get the offset of a string. + // Get the offset of a string in an ELF strtab. off_t get_offset(const char*) const; @@ -72,13 +80,15 @@ class Stringpool size_t len; // Allocated size of buffer. size_t alc; + // Buffer index. + unsigned int index; // Buffer. char data[1]; }; // Copy a string into the buffers, returning a canonical string. const char* - add_string(const char*); + add_string(const char*, Key*); struct Stringpool_hash { @@ -96,16 +106,19 @@ class Stringpool // Return whether s1 is a suffix of s2. static bool is_suffix(const char* s1, const char* s2); - // The hash table is a map from string names to offsets. We only - // use the offsets if we turn this into an ELF strtab section. + // The hash table is a map from string names to a pair of Key and + // ELF strtab offsets. We only use the offsets if we turn this into + // an ELF strtab section. + + typedef std::pair Val; #ifdef HAVE_TR1_UNORDERED_SET - typedef Unordered_map >, + std::allocator >, true> String_set_type; #else - typedef Unordered_map String_set_type; #endif @@ -118,9 +131,17 @@ class Stringpool String_set_type::iterator) const; }; + // List of Stringdata structures. + typedef std::list Stringdata_list; + + // Mapping from const char* to namepool entry. String_set_type string_set_; - std::list strings_; + // List of buffers. + Stringdata_list strings_; + // Size of ELF strtab. off_t strtab_size_; + // Next Stringdata index. + unsigned int next_index_; }; } // End namespace gold. diff --git a/gold/symtab.cc b/gold/symtab.cc index 091144a75ca..054e07fba5e 100644 --- a/gold/symtab.cc +++ b/gold/symtab.cc @@ -174,8 +174,7 @@ Symbol_table::~Symbol_table() size_t Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const { - return (reinterpret_cast(key.first) - ^ reinterpret_cast(key.second)); + return key.first ^ key.second; } // The symbol table key equality function. This is only called with @@ -216,17 +215,20 @@ Symbol_table::resolve_forwards(Symbol* from) const Symbol* Symbol_table::lookup(const char* name, const char* version) const { - name = this->namepool_.find(name); + Stringpool::Key name_key; + name = this->namepool_.find(name, &name_key); if (name == NULL) return NULL; + + Stringpool::Key version_key = 0; if (version != NULL) { - version = this->namepool_.find(version); + version = this->namepool_.find(version, &version_key); if (version == NULL) return NULL; } - Symbol_table_key key(name, version); + Symbol_table_key key(name_key, version_key); Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key); if (p == this->table_.end()) return NULL; @@ -282,19 +284,24 @@ template Symbol* Symbol_table::add_from_object(Object* object, const char *name, - const char *version, bool def, + Stringpool::Key name_key, + const char *version, + Stringpool::Key version_key, + bool def, const elfcpp::Sym& sym) { Symbol* const snull = NULL; std::pair ins = - this->table_.insert(std::make_pair(std::make_pair(name, version), snull)); + this->table_.insert(std::make_pair(std::make_pair(name_key, version_key), + snull)); std::pair insdef = std::make_pair(this->table_.end(), false); if (def) { - const char* const vnull = NULL; - insdef = this->table_.insert(std::make_pair(std::make_pair(name, vnull), + const Stringpool::Key vnull_key = 0; + insdef = this->table_.insert(std::make_pair(std::make_pair(name_key, + vnull_key), snull)); } @@ -379,7 +386,8 @@ Symbol_table::add_from_object(Object* object, { this->table_.erase(insdef.first); // Inserting insdef invalidated ins. - this->table_.erase(std::make_pair(name, version)); + this->table_.erase(std::make_pair(name_key, + version_key)); } return NULL; } @@ -477,12 +485,16 @@ Symbol_table::add_from_object( Symbol* res; if (ver == NULL) { - name = this->namepool_.add(name); - res = this->add_from_object(object, name, NULL, false, *psym); + Stringpool::Key name_key; + name = this->namepool_.add(name, &name_key); + res = this->add_from_object(object, name, name_key, NULL, 0, + false, *psym); } else { - name = this->namepool_.add(name, ver - name); + Stringpool::Key name_key; + name = this->namepool_.add(name, ver - name, &name_key); + bool def = false; ++ver; if (*ver == '@') @@ -490,8 +502,12 @@ Symbol_table::add_from_object( def = true; ++ver; } - ver = this->namepool_.add(ver); - res = this->add_from_object(object, name, ver, def, *psym); + + Stringpool::Key ver_key; + ver = this->namepool_.add(ver, &ver_key); + + res = this->add_from_object(object, name, name_key, ver, ver_key, + def, *psym); } *sympointers++ = res; @@ -525,12 +541,13 @@ Symbol_table::define_special_symbol(Target* target, const char* name, else { // Canonicalize NAME. - name = this->namepool_.add(name); + Stringpool::Key name_key; + name = this->namepool_.add(name, &name_key); Symbol* const snull = NULL; - const char* const vnull = NULL; + const Stringpool::Key ver_key = 0; std::pair ins = - this->table_.insert(std::make_pair(std::make_pair(name, vnull), + this->table_.insert(std::make_pair(std::make_pair(name_key, ver_key), snull)); if (!ins.second) @@ -937,7 +954,7 @@ Symbol_table::sized_finalize(off_t off, Stringpool* pool) } sym->set_value(value); - pool->add(sym->name()); + pool->add(sym->name(), NULL); ++count; off += sym_size; ++p; diff --git a/gold/symtab.h b/gold/symtab.h index f544e0664df..65898990c87 100644 --- a/gold/symtab.h +++ b/gold/symtab.h @@ -683,7 +683,7 @@ class Symbol_table // Canonicalize a symbol name for use in the hash table. const char* canonicalize_name(const char* name) - { return this->namepool_.add(name); } + { return this->namepool_.add(name, NULL); } // Possibly issue a warning for a reference to SYM at LOCATION which // is in OBJ. @@ -718,9 +718,9 @@ class Symbol_table // Add a symbol. template Symbol* - add_from_object(Object*, const char *name, - const char *version, bool def, - const elfcpp::Sym& sym); + add_from_object(Object*, const char *name, Stringpool::Key name_key, + const char *version, Stringpool::Key version_key, + bool def, const elfcpp::Sym& sym); // Resolve symbols. template @@ -783,7 +783,7 @@ class Symbol_table // The type of the symbol hash table. - typedef std::pair Symbol_table_key; + typedef std::pair Symbol_table_key; struct Symbol_table_hash { -- 2.30.2