Validate defined versions in prelink_image
Validate the list of defined versions explicitly, during library
prelinking, rather than implicitly as part of constructing the
VersionTracker in soinfo::link_image.
Doing the validation upfront allows removing the symbol lookup failure
code paths, which only happen on a library with invalid version
information.
Helps on the walleye 64-bit linker relocation benchmark (146.2ms ->
131.6ms)
Bug: none
Test: bionic unit tests
Change-Id: Id17508aba3af2863909f0526897c4277419322b7
diff --git a/linker/linker_soinfo.cpp b/linker/linker_soinfo.cpp
index 04aa27b..8efc9fe 100644
--- a/linker/linker_soinfo.cpp
+++ b/linker/linker_soinfo.cpp
@@ -36,6 +36,7 @@
#include <async_safe/log.h>
+#include "linker.h"
#include "linker_config.h"
#include "linker_debug.h"
#include "linker_globals.h"
@@ -43,7 +44,6 @@
#include "linker_utils.h"
// TODO(dimitry): These functions are currently located in linker.cpp - find a better place for it
-bool find_verdef_version_index(const soinfo* si, const version_info* vi, ElfW(Versym)* versym);
ElfW(Addr) call_ifunc_resolver(ElfW(Addr) resolver_addr);
int get_application_target_sdk_version();
@@ -135,22 +135,6 @@
return 0;
}
-bool soinfo::find_symbol_by_name(SymbolName& symbol_name,
- const version_info* vi,
- const ElfW(Sym)** symbol) const {
- uint32_t symbol_index;
- bool success =
- is_gnu_hash() ?
- gnu_lookup(symbol_name, vi, &symbol_index) :
- elf_lookup(symbol_name, vi, &symbol_index);
-
- if (success) {
- *symbol = symbol_index == 0 ? nullptr : symtab_ + symbol_index;
- }
-
- return success;
-}
-
static bool is_symbol_global_and_defined(const soinfo* si, const ElfW(Sym)* s) {
if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
ELF_ST_BIND(s->st_info) == STB_WEAK) {
@@ -177,9 +161,12 @@
verneed == (*verdef & ~kVersymHiddenBit);
}
-bool soinfo::gnu_lookup(SymbolName& symbol_name,
- const version_info* vi,
- uint32_t* symbol_index) const {
+const ElfW(Sym)* soinfo::find_symbol_by_name(SymbolName& symbol_name,
+ const version_info* vi) const {
+ return is_gnu_hash() ? gnu_lookup(symbol_name, vi) : elf_lookup(symbol_name, vi);
+}
+
+const ElfW(Sym)* soinfo::gnu_lookup(SymbolName& symbol_name, const version_info* vi) const {
uint32_t hash = symbol_name.gnu_hash();
uint32_t h2 = hash >> gnu_shift2_;
@@ -187,8 +174,6 @@
uint32_t word_num = (hash / bloom_mask_bits) & gnu_maskwords_;
ElfW(Addr) bloom_word = gnu_bloom_filter_[word_num];
- *symbol_index = 0;
-
TRACE_TYPE(LOOKUP, "SEARCH %s in %s@%p (gnu)",
symbol_name.get_name(), get_realpath(), reinterpret_cast<void*>(base));
@@ -197,7 +182,7 @@
TRACE_TYPE(LOOKUP, "NOT FOUND %s in %s@%p",
symbol_name.get_name(), get_realpath(), reinterpret_cast<void*>(base));
- return true;
+ return nullptr;
}
// bloom test says "probably yes"...
@@ -207,7 +192,7 @@
TRACE_TYPE(LOOKUP, "NOT FOUND %s in %s@%p",
symbol_name.get_name(), get_realpath(), reinterpret_cast<void*>(base));
- return true;
+ return nullptr;
}
// lookup versym for the version definition in this library
@@ -216,10 +201,7 @@
// which implies that the default version can be accepted; the second case results in
// verneed = 1 (kVersymGlobal) and implies that we should ignore versioned symbols
// for this library and consider only *global* ones.
- ElfW(Versym) verneed = 0;
- if (!find_verdef_version_index(this, vi, &verneed)) {
- return false;
- }
+ const ElfW(Versym) verneed = find_verdef_version_index(this, vi);
do {
ElfW(Sym)* s = symtab_ + n;
@@ -235,30 +217,24 @@
TRACE_TYPE(LOOKUP, "FOUND %s in %s (%p) %zd",
symbol_name.get_name(), get_realpath(), reinterpret_cast<void*>(s->st_value),
static_cast<size_t>(s->st_size));
- *symbol_index = n;
- return true;
+ return symtab_ + n;
}
} while ((gnu_chain_[n++] & 1) == 0);
TRACE_TYPE(LOOKUP, "NOT FOUND %s in %s@%p",
symbol_name.get_name(), get_realpath(), reinterpret_cast<void*>(base));
- return true;
+ return nullptr;
}
-bool soinfo::elf_lookup(SymbolName& symbol_name,
- const version_info* vi,
- uint32_t* symbol_index) const {
+const ElfW(Sym)* soinfo::elf_lookup(SymbolName& symbol_name, const version_info* vi) const {
uint32_t hash = symbol_name.elf_hash();
TRACE_TYPE(LOOKUP, "SEARCH %s in %s@%p h=%x(elf) %zd",
symbol_name.get_name(), get_realpath(),
reinterpret_cast<void*>(base), hash, hash % nbucket_);
- ElfW(Versym) verneed = 0;
- if (!find_verdef_version_index(this, vi, &verneed)) {
- return false;
- }
+ const ElfW(Versym) verneed = find_verdef_version_index(this, vi);
for (uint32_t n = bucket_[hash % nbucket_]; n != 0; n = chain_[n]) {
ElfW(Sym)* s = symtab_ + n;
@@ -276,8 +252,7 @@
symbol_name.get_name(), get_realpath(),
reinterpret_cast<void*>(s->st_value),
static_cast<size_t>(s->st_size));
- *symbol_index = n;
- return true;
+ return symtab_ + n;
}
}
@@ -285,8 +260,7 @@
symbol_name.get_name(), get_realpath(),
reinterpret_cast<void*>(base), hash, hash % nbucket_);
- *symbol_index = 0;
- return true;
+ return nullptr;
}
ElfW(Sym)* soinfo::find_symbol_by_address(const void* addr) {