[llvm] r290698 - Add a static_assert about the sizeof(GlobalValue)

[Reid Kleckner via llvm-commits]

Author: rnk
Date: Wed Dec 28 18:55:51 2016
New Revision: 290698

URL: http://llvm.org/viewvc/llvm-project?rev=290698&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/IR/Globals.cpp

Modified: llvm/trunk/lib/IR/Globals.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Globals.cpp?rev=290698&r1=290697&r2=290698&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Globals.cpp (original)
+++ llvm/trunk/lib/IR/Globals.cpp Wed Dec 28 18:55:51 2016
@@ -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();