[CFLAA] Add more offset-sensitivity tracking.

This patch teaches FunctionInfo about offsets.

Like the last patch, this one doesn't introduce any visible
functionality change (the core algorithm knows nothing about offsets;
they're just plumbed through). Tests will come when we start acting
differently because of the offsets.

Patch by Jia Chen.

(N.B. I made a tiny change to Jia's patch to avoid warnings by GCC: I
put DenseMapInfo specializations in the `llvm` namespace. Only realized
that those appeared when compiling locally. :) )

Differential Revision: https://reviews.llvm.org/D22634

llvm-svn: 276486

1 files changed, 0 insertions, 12 deletions

diff --git a/llvm/lib/Analysis/CFLGraph.h b/llvm/lib/Analysis/CFLGraph.h
index 7da5571c95c..43e622016ca 100644
--- a/llvm/lib/Analysis/CFLGraph.h
+++ b/llvm/lib/Analysis/CFLGraph.h
@@ -24,18 +24,6 @@
 namespace llvm {
 namespace cflaa {
 
-// We use UnknownOffset to represent pointer offsets that cannot be determined
-// at compile time. Note that MemoryLocation::UnknownSize cannot be used here
-// because we require a signed value.
-enum : int64_t { UnknownOffset = INT64_MAX };
-
-inline int64_t addOffset(int64_t LHS, int64_t RHS) {
-  if (LHS == UnknownOffset || RHS == UnknownOffset)
-    return UnknownOffset;
-  // FIXME: Do we need to guard against integer overflow here?
-  return LHS + RHS;
-}
-
 /// \brief The Program Expression Graph (PEG) of CFL analysis
 /// CFLGraph is auxiliary data structure used by CFL-based alias analysis to
 /// describe flow-insensitive pointer-related behaviors. Given an LLVM function,