Refactor code from inlining and globalopt that checks whether a function definition is unused, and enhance it so it can tell that functions which are only used by a blockaddress are in fact dead. This probably doesn't happen much on most code, but the Linux kernel's _THIS_IP_ can trigger this issue with blockaddress. (GlobalDCE can also handle the given tescase, but we only run that at -O3.) Found while looking at PR11180.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142572 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/include/llvm/Function.h b/include/llvm/Function.h
index 678651bbf1..b5916b7572 100644
--- a/include/llvm/Function.h
+++ b/include/llvm/Function.h
@@ -425,6 +425,12 @@ public:
   ///
   bool hasAddressTaken(const User** = 0) const;
 
+  /// isDefTriviallyDead - Return true if it is trivially safe to remove
+  /// this function definition from the module (because it isn't externally
+  /// visible, does not have its address taken, and has no callers).  To make
+  /// this more accurate, call removeDeadConstantUsers first.
+  bool isDefTriviallyDead() const;
+
   /// callsFunctionThatReturnsTwice - Return true if the function has a call to
   /// setjmp or other function that gcc recognizes as "returning twice".
   bool callsFunctionThatReturnsTwice() const;