[Lldb-commits] [lldb] r267405 - Handle invalid values of PLT entry size generated by linker

Omair Javaid via lldb-commits lldb-commits at lists.llvm.org
Mon Apr 25 06:45:39 PDT 2016

Author: omjavaid
Date: Mon Apr 25 08:45:39 2016
New Revision: 267405

URL: http://llvm.org/viewvc/llvm-project?rev=267405&view=rev
Handle invalid values of PLT entry size generated by linker

Make sure we figure out correct plt entry field in case linker has generated a small value below realistic entry size like 4 bytes or below.

Differential revision: http://reviews.llvm.org/D19252


Modified: lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp?rev=267405&r1=267404&r2=267405&view=diff
--- lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp (original)
+++ lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp Mon Apr 25 08:45:39 2016
@@ -2610,7 +2610,10 @@ GetPltEntrySizeAndOffset(const ELFSectio
     elf_xword plt_entsize = plt_hdr->sh_addralign ?
         llvm::alignTo (plt_hdr->sh_entsize, plt_hdr->sh_addralign) : plt_hdr->sh_entsize;
-    if (plt_entsize == 0)
+    // Some linkers e.g ld for arm, fill plt_hdr->sh_entsize field incorrectly.
+    // PLT entries relocation code in general requires multiple instruction and
+    // should be greater than 4 bytes in most cases. Try to guess correct size just in case.
+    if (plt_entsize <= 4)
         // The linker haven't set the plt_hdr->sh_entsize field. Try to guess the size of the plt
         // entries based on the number of entries and the size of the plt section with the

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