[lld] r341408 - When a relocation to an undefined symbol is an R_X86_64_PC32, an input

[Sterling Augustine via llvm-commits]

Author: saugustine
Date: Tue Sep  4 14:06:59 2018
New Revision: 341408

URL: http://llvm.org/viewvc/llvm-project?rev=341408&view=rev
Log:
When a relocation to an undefined symbol is an R_X86_64_PC32, an input
section will not have an input file. Don't crash under those circumstances.

Neither clang nor llvm-mc generates R_X86_64_PC32 relocations due to
https://reviews.llvm.org/D43383, which makes it hard to write a test case.
However, gcc does generate such relocations. I want to get a fix in now,
but will figure out a way to actually exercise this code path as soon
as I can.


Modified:
    lld/trunk/ELF/InputSection.cpp

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=341408&r1=341407&r2=341408&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Tue Sep  4 14:06:59 2018
@@ -947,7 +947,7 @@ void InputSectionBase::adjustSplitStackF
     // conservative.
     if (Defined *D = dyn_cast<Defined>(Rel.Sym))
       if (InputSection *IS = cast_or_null<InputSection>(D->Section))
-        if (!IS || IS->getFile<ELFT>()->SplitStack)
+        if (!IS || !IS->getFile<ELFT>() || IS->getFile<ELFT>()->SplitStack)
           continue;
 
     if (enclosingPrologueAttempted(Rel.Offset, Prologues))