Record function attribute "stackrealign" instead of using backend option
-force-align-stack.

Also, make changes to the driver so that -mno-stack-realign is no longer
an option exposed to the end-user that disallows stack realignment in
the backend.

Differential Revision: http://reviews.llvm.org/D11815

llvm-svn: 247451
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index e544ec5..fc1e8b9 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1494,8 +1494,8 @@
     FuncAttrs.addAttribute("stack-protector-buffer-size",
                            llvm::utostr(CodeGenOpts.SSPBufferSize));
 
-    if (!CodeGenOpts.StackRealignment)
-      FuncAttrs.addAttribute("no-realign-stack");
+    if (CodeGenOpts.StackRealignment)
+      FuncAttrs.addAttribute("stackrealign");
 
     // Add target-cpu and target-features attributes to functions. If
     // we have a decl for the function and it has a target attribute then