[llvm-objcopy] - Report SHT_GROUP sections with invalid alignment.
This patch fixes the reason of ubsan failure (UB detected)
happened after landing the D59638 (I had to revert it).
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap-ubsan/builds/11760/steps/check-llvm%20ubsan/logs/stdio)
Problem is the following. Our implementation of GroupSection assumes that
its address is 4 bytes aligned when writes it:
template <class ELFT>
void ELFSectionWriter<ELFT>::visit(const GroupSection &Sec) {
ELF::Elf32_Word *Buf =
reinterpret_cast<ELF::Elf32_Word *>(Out.getBufferStart() + Sec.Offset);
...
But the test case for D59638 did not set AddressAlign in YAML. So address was
not 4 bytes aligned since Sec.Offset was odd. That triggered the issue.
This patch teaches llvm-objcopy to report an error for such sections (which should
not met in reality), what is better than having UB.
Differential revision: https://reviews.llvm.org/D59695
llvm-svn: 356853
diff --git a/llvm/tools/llvm-objcopy/ELF/Object.cpp b/llvm/tools/llvm-objcopy/ELF/Object.cpp
index ccc6efa..39bee85 100644
--- a/llvm/tools/llvm-objcopy/ELF/Object.cpp
+++ b/llvm/tools/llvm-objcopy/ELF/Object.cpp
@@ -949,6 +949,9 @@
template <class ELFT>
void ELFBuilder<ELFT>::initGroupSection(GroupSection *GroupSec) {
+ if (GroupSec->Align % sizeof(ELF::Elf32_Word) != 0)
+ error("Invalid alignment " + Twine(GroupSec->Align) + " of group section " +
+ GroupSec->Name);
auto SecTable = Obj.sections();
auto SymTab = SecTable.template getSectionOfType<SymbolTableSection>(
GroupSec->Link,