From 36f848cda19e5a20a506a2c305ca8cc93b9bc14c Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Thu, 29 Dec 2016 00:55:51 +0000
Subject: [PATCH] Add a static_assert about the sizeof(GlobalValue)

I added one for Value back in r262045, and I'm starting to think we
should have these for any class with bitfields whose memory efficiency
really matters.

llvm-svn: 290698
---
 lib/IR/Globals.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/IR/Globals.cpp b/lib/IR/Globals.cpp
index 7cad629eaa7..31f89514151 100644
--- a/lib/IR/Globals.cpp
+++ b/lib/IR/Globals.cpp
@@ -30,6 +30,13 @@ using namespace llvm;
 //                            GlobalValue Class
 //===----------------------------------------------------------------------===//
 
+// GlobalValue should be a Constant, plus a type, a module, some flags, and an
+// intrinsic ID. Add an assert to prevent people from accidentally growing
+// GlobalValue while adding flags.
+static_assert(sizeof(GlobalValue) ==
+                  sizeof(Constant) + 2 * sizeof(void *) + 2 * sizeof(unsigned),
+              "unexpected GlobalValue size growth");
+
 bool GlobalValue::isMaterializable() const {
   if (const Function *F = dyn_cast<Function>(this))
     return F->isMaterializable();