From 30c1b436add85460c33b52565691adaa71a22236 Mon Sep 17 00:00:00 2001
From: Eugene Leviant <eleviant@accesssoftek.com>
Date: Tue, 14 Mar 2017 08:49:09 +0000
Subject: [PATCH] [ELF] Fix crash when .eh_frame(_hdr) is discarded

lld crashes when .eh_frame or .eh_frame_hdr section is discarded
in linker script and there is no PHDRS directive.

Differential revision: https://reviews.llvm.org/D30885

llvm-svn: 297712
---
 lld/ELF/Writer.cpp                          |  3 ++-
 lld/test/ELF/linkerscript/pt_gnu_eh_frame.s | 13 +++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 lld/test/ELF/linkerscript/pt_gnu_eh_frame.s

diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 344f86fa5ca3..3375fc25b54b 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -1355,7 +1355,8 @@ template <class ELFT> std::vector<PhdrEntry> Writer<ELFT>::createPhdrs() {
     Ret.push_back(std::move(RelRo));
 
   // PT_GNU_EH_FRAME is a special section pointing on .eh_frame_hdr.
-  if (!In<ELFT>::EhFrame->empty() && In<ELFT>::EhFrameHdr)
+  if (!In<ELFT>::EhFrame->empty() && In<ELFT>::EhFrameHdr &&
+      In<ELFT>::EhFrame->OutSec && In<ELFT>::EhFrameHdr->OutSec)
     AddHdr(PT_GNU_EH_FRAME, In<ELFT>::EhFrameHdr->OutSec->getPhdrFlags())
         ->add(In<ELFT>::EhFrameHdr->OutSec);
 
diff --git a/lld/test/ELF/linkerscript/pt_gnu_eh_frame.s b/lld/test/ELF/linkerscript/pt_gnu_eh_frame.s
new file mode 100644
index 000000000000..81b4c6307d4c
--- /dev/null
+++ b/lld/test/ELF/linkerscript/pt_gnu_eh_frame.s
@@ -0,0 +1,13 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: echo "SECTIONS { /DISCARD/ : { *(.eh_frame*) *(.eh_frame_hdr*) } }" > %t.script
+# RUN: ld.lld -o %t1 --eh-frame-hdr --script %t.script %t
+
+.global _start
+_start:
+ nop
+
+.section .dah,"ax",@progbits
+.cfi_startproc
+ nop
+.cfi_endproc