[BOLT] Bail frame analysis on PUSHes escaping vars

Summary:
Some PUSH instructions may contain memory addresses pushed to
the stack. If this memory address is from an object in the stack, cancel
further frame analysis for this function since it may be escaping a
variable.

This fixes a bug with deleting used stores (in frameopt) in hhvm trunk.

(cherry picked from FBD5270590)

bolt/Passes/FrameAnalysis.cpp

@@ -202,7 +202,7 @@ public:
       return true;
     }
 
-    if (BC.MIA->leaksStackAddress(Inst, *BC.MRI, SPT.HasFramePointer)) {
+    if (BC.MIA->escapesVariable(Inst, *BC.MRI, SPT.HasFramePointer)) {
       DEBUG(dbgs() << "Leaked stack address, giving up on this function.\n");
       DEBUG(dbgs() << "Blame insn: ");
       DEBUG(Inst.dump());
@@ -286,6 +286,21 @@ void FrameAnalysis::traverseCG(BinaryFunctionCallGraph &CG) {
   });
 
   CGWalker.walk();
+
+  DEBUG_WITH_TYPE("ra",
+    for (auto &MapEntry : ArgsTouchedMap) {
+      const auto *Func = MapEntry.first;
+      const auto &Set = MapEntry.second;
+      dbgs() << "Args accessed for " << Func->getPrintName() << ": ";
+      if (!Set.empty() && Set.count(std::make_pair(-1, 0))) {
+        dbgs() << "assume everything";
+      } else {
+        for (auto &Entry : Set) {
+          dbgs() << "[" << Entry.first << ", " << (int)Entry.second << "] ";
+        }
+      }
+      dbgs() << "\n";
+  });
 }
 
 bool FrameAnalysis::updateArgsTouchedFor(const BinaryFunction &BF, MCInst &Inst,
@@ -373,6 +388,8 @@ bool FrameAnalysis::computeArgsAccessed(BinaryFunction &BF) {
     return Updated;
   }
 
+  DEBUG(dbgs() << "Now computing args accessed for: " << BF.getPrintName()
+               << "\n");
   bool UpdatedArgsTouched = false;
   FrameAccessAnalysis FAA(BC, BF);
 

bolt/Passes/FrameOptimizer.cpp

@@ -197,6 +197,8 @@ void FrameOptimizerPass::removeUnusedStores(const FrameAnalysis &FA,
       DEBUG(dbgs() << "Unused store instruction: ");
       DEBUG(Inst.dump());
       DEBUG(dbgs() << "@BB: " << BB.getName() << "\n");
+      DEBUG(dbgs() << "FIE offset = " << FIEX->StackOffset
+                   << " size = " << (int)FIEX->Size << "\n");
       // Delete it!
       ToErase.push_back(std::make_pair(&BB, &Inst));
       Prev = &Inst;

bolt/Passes/RegAnalysis.cpp

@@ -68,7 +68,7 @@ RegAnalysis::RegAnalysis(BinaryContext &BC,
         CountFunctionsAllClobber += Count;
       ++NumFunctionsAllClobber;
     }
-    DEBUG_WITH_TYPE("fa",
+    DEBUG_WITH_TYPE("ra",
       dbgs() << "Killed regs set for func: " << Func->getPrintName() << "\n";
       const BitVector &RegsKilled = Iter->second;
       int RegIdx = RegsKilled.find_first();

bolt/Passes/StackPointerTracking.h

@@ -159,7 +159,7 @@ protected:
         return SUPERPOSITION;
 
       if (!HasFramePointer) {
-        if (MIA->leaksStackAddress(Point, *this->BC.MRI, false)) {
+        if (MIA->escapesVariable(Point, *this->BC.MRI, false)) {
           HasFramePointer = true;
         }
       }