[llvm] [BOLT] Gadget scanner: analyze functions without CFG information (PR #133461)

[Anatoly Trosinenko via llvm-commits]

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@@ -458,14 +448,141 @@ class PacRetAnalysis
     }
     std::vector<MCInstReference> Result;
     for (const MCInst *Inst : LastWritingInsts) {
-      MCInstInBBReference Ref = MCInstInBBReference::get(Inst, BF);
-      assert(Ref.BB != nullptr && "Expected Inst to be found");
+      MCInstReference Ref = MCInstReference::get(Inst, BF);
+      assert(Ref && "Expected Inst to be found");
       Result.push_back(MCInstReference(Ref));
     }
     return Result;
   }
 };
 
+class PacRetDFAnalysis
+    : public PacRetAnalysis,
+      public DataflowAnalysis<PacRetDFAnalysis, State, /*Backward=*/false,
+                              PacStatePrinter> {
+  using DFParent =
+      DataflowAnalysis<PacRetDFAnalysis, State, false, PacStatePrinter>;
+  friend DFParent;
+
+  using PacRetAnalysis::BC;
+  using PacRetAnalysis::computeNext;
+
+public:
+  PacRetDFAnalysis(BinaryFunction &BF, MCPlusBuilder::AllocatorIdTy AllocId,
+                   const std::vector<MCPhysReg> &RegsToTrackInstsFor)
+      : PacRetAnalysis(BF, RegsToTrackInstsFor), DFParent(BF, AllocId) {}
+
+  ErrorOr<const State &> getStateBefore(const MCInst &Inst) const override {
+    return DFParent::getStateBefore(Inst);
+  }
+
+  void run() override { DFParent::run(); }
+
+protected:
+  void preflight() {}
+
+  State getStartingStateAtBB(const BinaryBasicBlock &BB) {
+    if (BB.isEntryPoint())
+      return createEntryState();
+
+    return State();
+  }
+
+  State getStartingStateAtPoint(const MCInst &Point) { return State(); }
+
+  void doConfluence(State &StateOut, const State &StateIn) {
+    PacStatePrinter P(BC);
+    LLVM_DEBUG({
+      dbgs() << " PacRetAnalysis::Confluence(\n";
+      dbgs() << "   State 1: ";
+      P.print(dbgs(), StateOut);
+      dbgs() << "\n";
+      dbgs() << "   State 2: ";
+      P.print(dbgs(), StateIn);
+      dbgs() << ")\n";
+    });
+
+    StateOut.merge(StateIn);
+
+    LLVM_DEBUG({
+      dbgs() << "   merged state: ";
+      P.print(dbgs(), StateOut);
+      dbgs() << "\n";
+    });
+  }
+
+  StringRef getAnnotationName() const { return "PacRetAnalysis"; }
----------------
atrosinenko wrote:

Replaced with the updated class name (same for the second subclass), thanks! This is rather verbose, but after all, which variant of analysis produced the annotation is quite useful information.

https://github.com/llvm/llvm-project/pull/133461