Add CodeGen support for alignment on globals, both for unusual natural

alignment and alignment attributes.

llvm-svn: 51676

2 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 0b7d30ac500..e5bd15e8566 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -477,6 +477,12 @@ void CodeGenModule::EmitGlobalVarInit(const VarDecl *D) {
          "Initializer codegen type mismatch!");
   GV->setInitializer(Init);
 
+  unsigned Align = Context.getTypeAlign(D->getType());
+  if (const AlignedAttr* AA = D->getAttr<AlignedAttr>()) {
+    Align = std::max(Align, AA->getAlignment());
+  }
+  GV->setAlignment(Align / 8);
+
   if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>())
     setVisibility(GV, attr->getVisibility());
   // FIXME: else handle -fvisibility
diff --git a/clang/test/CodeGen/var-align.c b/clang/test/CodeGen/var-align.c
new file mode 100644
index 00000000000..be585c052e8
--- /dev/null
+++ b/clang/test/CodeGen/var-align.c
@@ -0,0 +1,4 @@
+// RUN: clang -emit-llvm %s -o - | grep "align 16" | count 2
+
+__attribute((aligned(16))) float a[128];
+union {int a[4]; __attribute((aligned(16))) float b[4];} u;