strip exported symbols from tools that build with TOOL_NO_EXPORTS=1.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65543 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile.rules b/Makefile.rules
index c9251e7..388372e 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -1067,6 +1067,24 @@
endif
#---------------------------------------------------------
+# Prune Exports
+#---------------------------------------------------------
+
+# If the tool opts in with TOOL_NO_EXPORTS, optimize startup time of the app by
+# not exporting all of the weak symbols from the binary. This reduces dyld
+# startup time by 4x on darwin in some cases.
+ifdef TOOL_NO_EXPORTS
+ifeq ($(OS),Darwin)
+LD.Flags += -Wl,-exported_symbol -Wl,_main
+endif
+
+ifeq ($(OS), $(filter $(OS), Linux NetBSD FreeBSD))
+LD.Flags += -Wl,--version-script=Driver.map
+endif
+endif
+
+
+#---------------------------------------------------------
# Provide targets for building the tools
#---------------------------------------------------------
all-local:: $(ToolBuildPath)