commit 60dd73a693472865fd6978dc62252c41ee22fb46
author Peter Collingbourne <peter@pcc.me.uk> Tue Oct 01 16:10:13 2019 +0000
committer Peter Collingbourne <peter@pcc.me.uk> Tue Oct 01 16:10:13 2019 +0000
tree 5e8cbb9f821ef48f50b232ed6c536c6c9175015d
parent ff54d4faecc1687516d1ae1e3d81a9c9d238123d

ELF: Add .interp synthetic sections first in createSyntheticSections().

Our .interp section is not a SyntheticSection. As a result, it terminates the
loop in removeUnusedSyntheticSections(). This has at least two consequences:

- The synthetic .bss and .bss.rel.ro sections are always present in
  dynamically linked executables, even when they are not needed.
- The synthetic .ARM.exidx (and possibly other) sections are always present
  in partitions other than the last one, even when not needed.
  .ARM.exidx in particular is problematic because it assumes that its
  list of code sections is non-empty in getLinkOrderDep(), which can
  lead to a crash if the partition does not have any code sections.

Fix these problems by moving the creation of the .interp sections to the
top of createSyntheticSections(). While here, make the code a little less
error-prone by changing the add() lambdas to take a SyntheticSection instead
of an InputSectionBase.

Differential Revision: https://reviews.llvm.org/D68256

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@373347 91177308-0d34-0410-b5e6-96231b3b80d8