[RuntimeDyld] Don't try to allocate sections with align 0.
ELF sections allow 0 for the alignment, which is specified to
be the same as 1. However many clients do not expect this and
will behave poorly in the presence of a 0-aligned section (for
example by trying to modulo something by the section alignment).
We can be more polite by making sure that we always pass a
non-zero value to clients.
Differential Revision: https://reviews.llvm.org/D57482
llvm-svn: 352694
diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 473a812..589cdcb 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -743,6 +743,11 @@
bool IsReadOnly = isReadOnlyData(Section);
uint64_t DataSize = Section.getSize();
+ // An alignment of 0 (at least with ELF) is identical to an alignment of 1,
+ // while being more "polite". Other formats do not support 0-aligned sections
+ // anyway, so we should guarantee that the alignment is always at least 1.
+ Alignment = std::max(1u, Alignment);
+
StringRef Name;
if (auto EC = Section.getName(Name))
return errorCodeToError(EC);