From d4dea164dd453f567d9d33f3c158c33d6904987f Mon Sep 17 00:00:00 2001
From: Eugene Leviant <evgeny.leviant@gmail.com>
Date: Fri, 23 Sep 2016 13:17:16 +0000
Subject: [PATCH] Linker script: fix crash when discarding section

If section contains local symbols ldd crashes, because local
symbols are added to symbol table before section is discarded
by linker script processor. This patch calls copyLocalSymbols()
after createSections, so discarded section symbols are not copied

llvm-svn: 282244
---
 lld/ELF/Writer.cpp                          |  5 +++--
 lld/test/ELF/linkerscript/discard-section.s | 10 ++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 lld/test/ELF/linkerscript/discard-section.s

diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index e42240fdd830..5ab9d64e1160 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -244,8 +244,6 @@ template <class ELFT> static std::vector<DefinedCommon *> getCommonSymbols() {
 
 // The main function of the writer.
 template <class ELFT> void Writer<ELFT>::run() {
-  if (Config->Discard != DiscardPolicy::All)
-    copyLocalSymbols();
   addReservedSymbols();
 
   if (Target->NeedsThunks)
@@ -262,6 +260,9 @@ template <class ELFT> void Writer<ELFT>::run() {
     Script<ELFT>::X->processCommands(Factory);
   }
 
+  if (Config->Discard != DiscardPolicy::All)
+    copyLocalSymbols();
+
   finalizeSections();
   if (HasError)
     return;
diff --git a/lld/test/ELF/linkerscript/discard-section.s b/lld/test/ELF/linkerscript/discard-section.s
new file mode 100644
index 000000000000..d7d2acff1b47
--- /dev/null
+++ b/lld/test/ELF/linkerscript/discard-section.s
@@ -0,0 +1,10 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: echo "SECTIONS { /DISCARD/ : { *(.aaa*) } }" > %t.script
+# RUN: ld.lld -o %t1 --script %t.script %t
+# RUN: llvm-objdump -section-headers %t1 | FileCheck %s
+# CHECK-NOT: .aaa
+
+.section .aaa,"a"
+aaa:
+  .quad 0