[RuntimeDyld] Apply padding and alignment bumps to all sections with stubs, and

increase the MachO/x86-64 stub alignment to 8.

Stub alignment should be guaranteed for any section containing RuntimeDyld
stubs/GOT-entries. To do this we should pad and align all sections containing
stubs, not just code sections.

This commit also bumps the MachO/x86-64 stub alignment to 8, so that GOT entries
will be aligned.

llvm-svn: 362139

2 files changed, 6 insertions, 7 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index f99868db443..b1d22b89af0 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -799,13 +799,12 @@ RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
     pData = data.data();
   }
 
-  // Code section alignment needs to be at least as high as stub alignment or
-  // padding calculations may by incorrect when the section is remapped to a
-  // higher alignment.
-  if (IsCode) {
+  // If there are any stubs then the section alignment needs to be at least as
+  // high as stub alignment or padding calculations may by incorrect when the
+  // section is remapped.
+  if (StubBufSize != 0) {
     Alignment = std::max(Alignment, getStubAlignment());
-    if (StubBufSize > 0)
-      PaddingSize += getStubAlignment() - 1;
+    PaddingSize += getStubAlignment() - 1;
   }
 
   // Some sections, such as debug info, don't need to be loaded for execution.
diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOX86_64.h b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOX86_64.h
index 249f8dc0f29..28febbdb948 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOX86_64.h
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOX86_64.h
@@ -28,7 +28,7 @@ public:
 
   unsigned getMaxStubSize() const override { return 8; }
 
-  unsigned getStubAlignment() override { return 1; }
+  unsigned getStubAlignment() override { return 8; }
 
   Expected<relocation_iterator>
   processRelocationRef(unsigned SectionID, relocation_iterator RelI,