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

[Kristof Beyls 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"; }
----------------
kbeyls wrote:

Maybe this should return "PacRetDFAnalysis" now?

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