From: kettenis <kettenis@openbsd.org>
Date: Sun, 23 Apr 2023 21:08:26 +0000 (+0000)
Subject: Don't create IBT .plt if there are no PLT entries.  Cherry picked from
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=a3cd701e6e5f3719a4f464aecc0f437a5f4de7af;p=openbsd

Don't create IBT .plt if there are no PLT entries.  Cherry picked from
upstream.  Fixes several issues including problems with ld.bfd when it
sees such a .plt in an object file that is getting linked into a binary.

ok deraadt@
---

diff --git a/gnu/llvm/lld/ELF/SyntheticSections.cpp b/gnu/llvm/lld/ELF/SyntheticSections.cpp
index 187b2ac90c2..32248aac70d 100644
--- a/gnu/llvm/lld/ELF/SyntheticSections.cpp
+++ b/gnu/llvm/lld/ELF/SyntheticSections.cpp
@@ -2729,6 +2729,8 @@ size_t IBTPltSection::getSize() const {
   return 16 + in.plt->getNumEntries() * target->pltEntrySize;
 }
 
+bool IBTPltSection::isNeeded() const { return in.plt->getNumEntries() > 0; }
+
 // The string hash function for .gdb_index.
 static uint32_t computeGdbHash(StringRef s) {
   uint32_t h = 0;
diff --git a/gnu/llvm/lld/ELF/SyntheticSections.h b/gnu/llvm/lld/ELF/SyntheticSections.h
index bc24922598f..bc79fcdd49f 100644
--- a/gnu/llvm/lld/ELF/SyntheticSections.h
+++ b/gnu/llvm/lld/ELF/SyntheticSections.h
@@ -769,6 +769,7 @@ class IBTPltSection : public SyntheticSection {
 public:
   IBTPltSection();
   void writeTo(uint8_t *Buf) override;
+  bool isNeeded() const override;
   size_t getSize() const override;
 };