[lld] r297712 - [ELF] Fix crash when .eh_frame(_hdr) is discarded

[Eugene Leviant via llvm-commits]

Author: evgeny777
Date: Tue Mar 14 03:49:09 2017
New Revision: 297712

URL: http://llvm.org/viewvc/llvm-project?rev=297712&view=rev
Log:
[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

Added:
    lld/trunk/test/ELF/linkerscript/pt_gnu_eh_frame.s
Modified:
    lld/trunk/ELF/Writer.cpp

Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=297712&r1=297711&r2=297712&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Tue Mar 14 03:49:09 2017
@@ -1355,7 +1355,8 @@ template <class ELFT> std::vector<PhdrEn
     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);
 

Added: lld/trunk/test/ELF/linkerscript/pt_gnu_eh_frame.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/linkerscript/pt_gnu_eh_frame.s?rev=297712&view=auto
==============================================================================
--- lld/trunk/test/ELF/linkerscript/pt_gnu_eh_frame.s (added)
+++ lld/trunk/test/ELF/linkerscript/pt_gnu_eh_frame.s Tue Mar 14 03:49:09 2017
@@ -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", at progbits
+.cfi_startproc
+ nop
+.cfi_endproc