If a .syms file is available alongside a sanitizer runtime, pass it to the
linker via --dynamic-list instead of using --export-dynamic. This reduces the
size of the dynamic symbol table, and thus of the binary (in some cases by up
to ~30%).
llvm-svn: 177783
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index cb84e0a..2581ae3 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1575,7 +1575,8 @@
static void addSanitizerRTLinkFlagsLinux(
const ToolChain &TC, const ArgList &Args, ArgStringList &CmdArgs,
- const StringRef Sanitizer, bool BeforeLibStdCXX) {
+ const StringRef Sanitizer, bool BeforeLibStdCXX,
+ bool ExportSymbols = true) {
// Sanitizer runtime is located in the Linux library directory and
// has name "libclang_rt.<Sanitizer>-<ArchName>.a".
SmallString<128> LibSanitizer(TC.getDriver().ResourceDir);
@@ -1599,7 +1600,17 @@
CmdArgs.push_back("-lpthread");
CmdArgs.push_back("-ldl");
- CmdArgs.push_back("-export-dynamic");
+
+ // If possible, use a dynamic symbols file to export the symbols from the
+ // runtime library. If we can't do so, use -export-dynamic instead to export
+ // all symbols from the binary.
+ if (ExportSymbols) {
+ if (llvm::sys::fs::exists(LibSanitizer + ".syms"))
+ CmdArgs.push_back(
+ Args.MakeArgString("--dynamic-list=" + LibSanitizer + ".syms"));
+ else
+ CmdArgs.push_back("-export-dynamic");
+ }
}
/// If AddressSanitizer is enabled, add appropriate linker flags (Linux).
@@ -1666,7 +1677,7 @@
// Need a copy of sanitizer_common. This could come from another sanitizer
// runtime; if we're not including one, include our own copy.
if (!HasOtherSanitizerRt)
- addSanitizerRTLinkFlagsLinux(TC, Args, CmdArgs, "san", true);
+ addSanitizerRTLinkFlagsLinux(TC, Args, CmdArgs, "san", true, false);
addSanitizerRTLinkFlagsLinux(TC, Args, CmdArgs, "ubsan", false);