[sancov] specifying sanitizer coverage dependencies.

Summary:
These dependencies would be used in the future to reduce the number
of instrumented blocks(http://reviews.llvm.org/rL262103)

This is submitted as a separate CL because of previous problems with
ARM.

Subscribers: aemerson

Differential Revision: http://reviews.llvm.org/D18227

llvm-svn: 263797

llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp

@@ -31,6 +31,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Analysis/EHPersonalities.h"
+#include "llvm/Analysis/PostDominators.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/DataLayout.h"
@@ -160,7 +161,12 @@ class SanitizerCoverageModule : public ModulePass {
     return "SanitizerCoverageModule";
   }
 
- private:
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<DominatorTreeWrapperPass>();
+    AU.addRequired<PostDominatorTreeWrapperPass>();
+  }
+
+private:
   void InjectCoverageForIndirectCalls(Function &F,
                                       ArrayRef<Instruction *> IndirCalls);
   void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);