[PATCH] Add Forward-Edge Control-Flow Integrity support

[JF Bastien]

Looks good overall.

================
Comment at: include/llvm/CodeGen/ForwardControlFlowIntegrity.h:45
@@ +44,3 @@
+                              bool CFIEnforcing, std::string CFIFuncName);
+  virtual ~ForwardControlFlowIntegrity();
+
----------------
`override`

================
Comment at: include/llvm/CodeGen/ForwardControlFlowIntegrity.h:67
@@ +66,3 @@
+  /// for the table
+  typedef DenseMap<FunctionType *, struct CFIConstants> CFITables;
+
----------------
You can drop `struct` here.

================
Comment at: test/CodeGen/X86/cfi_enforcing.ll:1
@@ +1,2 @@
+; RUN: llc -fcfi -cfi-enforcing <%s | FileCheck %s
+
----------------
Could you test x86-32 as well here? No triple below, pass it to the command line instead.

================
Comment at: test/CodeGen/X86/cfi_enforcing.ll:14
@@ +13,3 @@
+; CHECK-NOT: callq __llvm_cfi_pointer_warning
+; CHECK: callq   *%r
+  ret i32 0
----------------
Add the registers here, to make sure the masks are on the right thing. You can use FileCheck's capture capabilities to avoid hard-coding the register.

================
Comment at: test/CodeGen/X86/cfi_enforcing.ll:27
@@ +26,3 @@
+}
+; XFAIL: win32
+
----------------
Could you explain why?

http://reviews.llvm.org/D4167