Optimize GNU hash linking for large inputs
Symbol lookup is O(L) where L is the number of libraries to search (e.g.
in the global and local lookup groups). Factor out the per-DSO work into
soinfo_do_lookup_impl, and optimize for the situation where all the DSOs
are using DT_GNU_HASH (rather than SysV hashes).
To load a set of libraries, the loader first constructs an auxiliary list
of libraries (SymbolLookupList, containing SymbolLookupLib objects). The
SymbolLookupList is reused for each DSO in a load group. (-Bsymbolic is
accommodated by modifying the SymbolLookupLib at the front of the list.)
To search for a symbol, soinfo_do_lookup_impl has a small loop that first
scans a vector of GNU bloom filters looking for a possible match.
There was a slight improvement from templatizing soinfo_do_lookup_impl
and skipping the does-this-DSO-lack-GNU-hash check.
Rewrite the relocation processing loop to be faster. There are specialized
functions that handle the expected relocation types in normal relocation
sections and in PLT relocation sections.
This CL can reduce the initial link time of large programs by around
40-50% (e.g. audioserver, cameraserver, etc). On the linker relocation
benchmark (64-bit walleye), it reduces the time from 131.6ms to 71.9ms.
Bug: http://b/143577578 (incidentally fixed by this CL)
Test: bionic-unit-tests
Change-Id: If40a42fb6ff566570f7280b71d58f7fa290b9343
diff --git a/linker/linker.h b/linker/linker.h
index 16c65a1..80c11d0 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -85,23 +85,6 @@
DISALLOW_COPY_AND_ASSIGN(VersionTracker);
};
-bool soinfo_do_lookup(soinfo* si_from, const char* name, const version_info* vi,
- soinfo** si_found_in, const soinfo_list_t& global_group,
- const soinfo_list_t& local_group, const ElfW(Sym)** symbol);
-
-enum RelocationKind {
- kRelocAbsolute = 0,
- kRelocRelative,
- kRelocCopy,
- kRelocSymbol,
- kRelocSymbolCached,
- kRelocMax
-};
-
-void count_relocation(RelocationKind kind);
-
-void print_linker_stats();
-
soinfo* get_libdl_info(const soinfo& linker_si);
soinfo* find_containing_library(const void* p);
@@ -205,4 +188,6 @@
bool must_use_address = false;
};
+int get_application_target_sdk_version();
ElfW(Versym) find_verdef_version_index(const soinfo* si, const version_info* vi);
+bool validate_verdef_section(const soinfo* si);