From 5e7c782b29d4317db9098e7482046fbbc9933054 Mon Sep 17 00:00:00 2001
From: Nico Weber <nicolasweber@gmx.de>
Date: Fri, 27 Dec 2013 22:38:59 +0000
Subject: Strip dead code when linking by default with BFD ld (linux, ...) and
 ld64 (os x).

This reduces the size of clang-format from 22 MB to 1.8 MB, diagtool goes from
21 MB to 2.8 MB, libclang.so goes from 29 MB to 20 MB, etc.  The size of the
bin/ folder shrinks from 270 MB to 200 MB.

Targets that support plugins and don't already use EXPORTED_SYMBOL_FILE
(which libclang and libLTO already do) can set NO_DEAD_STRIP to opt out.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198087 91177308-0d34-0410-b5e6-96231b3b80d8
---
 Makefile.rules | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'Makefile.rules')

diff --git a/Makefile.rules b/Makefile.rules
index 68f6cf8ec5..1eeadac198 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -608,6 +608,22 @@ ifndef KEEP_SYMBOLS
   Install.StripFlag += -s
 endif
 
+# By default, strip dead symbols at link time
+ifneq ($(HOST_OS), $(filter $(HOST_OS), Cygwin MingW))
+ifneq ($(HOST_OS),Darwin)
+  CXX.Flags += -ffunction-sections -fdata-sections
+endif
+endif
+ifndef NO_DEAD_STRIP
+  ifeq ($(HOST_OS),Darwin)
+    LD.Flags += -Wl,-dead_strip
+  else
+    ifneq ($(HOST_OS), $(filter $(HOST_OS), Cygwin MingW))
+      LD.Flags += -Wl,--gc-sections
+    endif
+  endif
+endif
+
 # Adjust linker flags for building an executable
 ifneq ($(HOST_OS), $(filter $(HOST_OS), Cygwin MingW))
   ifndef TOOL_NO_EXPORTS
-- 
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