BGV: Count Add/Keyswitch in one level for OpenFHE

lib/Analysis/AddAndKeySwitchCountAnalysis/AddAndKeySwitchCountAnalysis.cpp

@@ -0,0 +1,155 @@
+#include "lib/Analysis/AddAndKeySwitchCountAnalysis/AddAndKeySwitchCountAnalysis.h"
+
+#include "lib/Analysis/SecretnessAnalysis/SecretnessAnalysis.h"
+#include "lib/Dialect/Mgmt/IR/MgmtAttributes.h"
+#include "lib/Dialect/Mgmt/IR/MgmtOps.h"
+#include "lib/Dialect/Secret/IR/SecretOps.h"
+#include "lib/Dialect/TensorExt/IR/TensorExtOps.h"
+#include "llvm/include/llvm/ADT/TypeSwitch.h"              // from @llvm-project
+#include "mlir/include/mlir/Analysis/DataFlowFramework.h"  // from @llvm-project
+#include "mlir/include/mlir/Dialect/Arith/IR/Arith.h"      // from @llvm-project
+#include "mlir/include/mlir/Dialect/Tensor/IR/Tensor.h"    // from @llvm-project
+#include "mlir/include/mlir/IR/Operation.h"                // from @llvm-project
+#include "mlir/include/mlir/IR/Value.h"                    // from @llvm-project
+#include "mlir/include/mlir/IR/Visitors.h"                 // from @llvm-project
+#include "mlir/include/mlir/Support/LLVM.h"                // from @llvm-project
+
+namespace mlir {
+namespace heir {
+
+LogicalResult CountAnalysis::visitOperation(
+    Operation *op, ArrayRef<const CountLattice *> operands,
+    ArrayRef<CountLattice *> results) {
+  auto propagate = [&](Value value, const CountState &state) {
+    auto *lattice = getLatticeElement(value);
+    ChangeResult changed = lattice->join(state);
+    propagateIfChanged(lattice, changed);
+  };
+
+  llvm::TypeSwitch<Operation &>(*op)
+      .Case<secret::GenericOp>([&](auto genericOp) {
+        Block *body = genericOp.getBody();
+        for (auto i = 0; i != body->getNumArguments(); ++i) {
+          auto blockArg = body->getArgument(i);
+          // one Vfresh
+          propagate(blockArg, CountState(1, 0));
+        }
+      })
+      .Case<arith::AddIOp, arith::SubIOp>([&](auto &op) {
+        // condition on result secretness
+        SmallVector<OpResult> secretResults;
+        getSecretResults(op, secretResults);
+        if (secretResults.empty()) {
+          return;
+        }
+
+        CountState zeroState(0, 0);
+        SmallVector<OpOperand *> secretOperands;
+        getSecretOperands(op, secretOperands);
+        for (auto *operand : secretOperands) {
+          auto countState = operands[operand->getOperandNumber()]->getValue();
+          zeroState = zeroState + countState;
+        }
+
+        for (auto result : secretResults) {
+          propagate(result, zeroState);
+        }
+      })
+      .Case<arith::MulIOp>([&](auto &op) {
+        SmallVector<OpResult> secretResults;
+        getSecretResults(op, secretResults);
+        if (secretResults.empty()) {
+          return;
+        }
+
+        // now noise is Vmult
+        // TODO(#1168): we can actually do a more fine grained analysis here
+        // distinguishing ct-ct and ct-pt
+        propagate(op.getResult(), CountState(1, 0));
+      })
+      .Case<mgmt::RelinearizeOp, tensor_ext::RotateOp>([&](auto &op) {
+        auto secretness = ensureSecretness(op, op->getOperand(0));
+        if (!secretness) {
+          return;
+        }
+
+        auto state = operands[0]->getValue();
+        if (!state.isInitialized()) {
+          return;
+        }
+
+        propagate(op.getResult(), state.keySwitch());
+      })
+      // TODO(#1174): in BGV tensor::ExtractOp is assumed to be always
+      // mul+const
+      .Case<tensor::ExtractOp>([&](auto &op) {
+        auto secretness = ensureSecretness(op, op.getResult());
+        if (!secretness) {
+          return;
+        }
+
+        // now noise is Vmult + one Vks
+        propagate(op.getResult(), CountState(1, 1));
+      })
+      .Case<mgmt::ModReduceOp>([&](auto modReduceOp) {
+        // implicitly ensure that the operand is secret
+
+        propagate(modReduceOp.getResult(), CountState(0, 0));
+      });
+  // should not propagate through mgmt::ModReduceOp
+  return success();
+}
+
+void annotateCount(Operation *top, DataFlowSolver *solver) {
+  auto getIntegerAttr = [&](int level) {
+    return IntegerAttr::get(IntegerType::get(top->getContext(), 64), level);
+  };
+
+  auto maxAddCount = 0;
+  auto maxKeySwitchCount = 0;
+
+  auto getCount = [&](Value value) {
+    auto state = solver->lookupState<CountLattice>(value)->getValue();
+    // update the max
+    maxAddCount = std::max(maxAddCount, state.getAddCount());
+    maxKeySwitchCount = std::max(maxKeySwitchCount, state.getKeySwitchCount());
+    return std::make_tuple(state.getAddCount(), state.getKeySwitchCount());
+  };
+
+  top->walk<WalkOrder::PreOrder>([&](secret::GenericOp genericOp) {
+    for (auto i = 0; i != genericOp.getBody()->getNumArguments(); ++i) {
+      auto blockArg = genericOp.getBody()->getArgument(i);
+      auto [addCount, keySwitchCount] = getCount(blockArg);
+      if (addCount != 0) {
+        genericOp.setArgAttr(i, "addCount", getIntegerAttr(addCount));
+      }
+      if (keySwitchCount != 0) {
+        genericOp.setArgAttr(i, "keySwitchCount",
+                             getIntegerAttr(keySwitchCount));
+      }
+    }
+
+    genericOp.getBody()->walk<WalkOrder::PreOrder>([&](Operation *op) {
+      if (op->getNumResults() == 0) {
+        return;
+      }
+      auto [addCount, keySwitchCount] = getCount(op->getResult(0));
+      if (addCount != 0) {
+        op->setAttr("addCount", getIntegerAttr(addCount));
+      }
+      if (keySwitchCount != 0) {
+        op->setAttr("keySwitchCount", getIntegerAttr(keySwitchCount));
+      }
+    });
+
+    // annotate mgmt::OpenfheParamsAttr to func::FuncOp containing the genericOp
+    auto *funcOp = genericOp->getParentOp();
+    auto openfheParamAttr = mgmt::OpenfheParamsAttr::get(
+        funcOp->getContext(), maxAddCount, maxKeySwitchCount);
+    funcOp->setAttr(mgmt::MgmtDialect::kArgOpenfheParamsAttrName,
+                    openfheParamAttr);
+  });
+}
+
+}  // namespace heir
+}  // namespace mlir

lib/Analysis/AddAndKeySwitchCountAnalysis/AddAndKeySwitchCountAnalysis.h

@@ -0,0 +1,123 @@
+#ifndef LIB_ANALYSIS_ADDANDKEYSWITCHCOUNTANALYSISANALYSIS_ADDANDKEYSWITCHCOUNTANALYSISANALYSIS_H_
+#define LIB_ANALYSIS_ADDANDKEYSWITCHCOUNTANALYSISANALYSIS_ADDANDKEYSWITCHCOUNTANALYSISANALYSIS_H_
+
+#include "lib/Analysis/SecretnessAnalysis/SecretnessAnalysis.h"
+#include "mlir/include/mlir/Analysis/DataFlow/SparseAnalysis.h"  // from @llvm-project
+#include "mlir/include/mlir/IR/Diagnostics.h"  // from @llvm-project
+#include "mlir/include/mlir/IR/Operation.h"    // from @llvm-project
+#include "mlir/include/mlir/IR/Value.h"        // from @llvm-project
+
+namespace mlir {
+namespace heir {
+
+// This analysis should be used after --secret-with-mgmt-bgv
+// but before --secret-distribute-generic
+// where a whole secret::GenericOp is assumed
+//
+// this follows strictly the strategy of modulus switch
+// right before multiplication including the first.
+// namely FLEXIBLEAUTOEXT in OpenFHE
+//
+// OpenFHE only supports setting EvalAddCount/EvalKeySwitchCount
+// for BGV/BFV, so HEIR only supports BGV here
+//
+// For not include-the-first, the addCount for the L-th level
+// might be overestimated, as we can not distinguish between
+// Vmult and Vfresh
+
+class CountState {
+ public:
+  CountState() : initialized(false), addCount(0), keySwitchCount(0) {}
+  explicit CountState(int addCount, int keySwitchCount)
+      : initialized(true), addCount(addCount), keySwitchCount(keySwitchCount) {}
+  ~CountState() = default;
+
+  int getAddCount() const {
+    assert(isInitialized());
+    return addCount;
+  }
+
+  int getKeySwitchCount() const {
+    assert(isInitialized());
+    return keySwitchCount;
+  }
+
+  bool operator==(const CountState &rhs) const {
+    return initialized == rhs.initialized && addCount == rhs.addCount &&
+           keySwitchCount == rhs.keySwitchCount;
+  }
+
+  bool isInitialized() const { return initialized; }
+
+  CountState operator+(const CountState &rhs) const {
+    assert(isInitialized() && rhs.isInitialized());
+    return CountState{addCount + rhs.addCount,
+                      keySwitchCount + rhs.keySwitchCount};
+  }
+
+  CountState keySwitch() const {
+    assert(isInitialized());
+    return CountState{addCount, keySwitchCount + 1};
+  }
+
+  CountState max(const CountState &rhs) const {
+    assert(isInitialized() && rhs.isInitialized());
+    return CountState{std::max(addCount, rhs.addCount),
+                      std::max(keySwitchCount, rhs.keySwitchCount)};
+  }
+
+  static CountState join(const CountState &lhs, const CountState &rhs) {
+    if (!lhs.isInitialized()) return rhs;
+    if (!rhs.isInitialized()) return lhs;
+
+    return lhs.max(rhs);
+  }
+
+  void print(llvm::raw_ostream &os) const {
+    if (isInitialized()) {
+      os << "CountState(" << addCount << ", " << keySwitchCount << ")";
+    } else {
+      os << "CountState(uninitialized)";
+    }
+  }
+
+  friend llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
+                                       const CountState &state) {
+    state.print(os);
+    return os;
+  }
+
+ private:
+  bool initialized;
+  int addCount;  // how many Vmult or Vfresh (before first multiplication)
+                 // encountered
+  int keySwitchCount;
+};
+
+class CountLattice : public dataflow::Lattice<CountState> {
+ public:
+  using Lattice::Lattice;
+};
+
+class CountAnalysis
+    : public dataflow::SparseForwardDataFlowAnalysis<CountLattice>,
+      public SecretnessAnalysisDependent<CountAnalysis> {
+ public:
+  using SparseForwardDataFlowAnalysis::SparseForwardDataFlowAnalysis;
+  friend class SecretnessAnalysisDependent<CountAnalysis>;
+
+  void setToEntryState(CountLattice *lattice) override {
+    propagateIfChanged(lattice, lattice->join(CountState()));
+  }
+
+  LogicalResult visitOperation(Operation *op,
+                               ArrayRef<const CountLattice *> operands,
+                               ArrayRef<CountLattice *> results) override;
+};
+
+void annotateCount(Operation *top, DataFlowSolver *solver);
+
+}  // namespace heir
+}  // namespace mlir
+
+#endif  // LIB_ANALYSIS_ADDANDKEYSWITCHCOUNTANALYSISANALYSIS_ADDANDKEYSWITCHCOUNTANALYSISANALYSIS_H_

lib/Analysis/AddAndKeySwitchCountAnalysis/BUILD

@@ -0,0 +1,20 @@
+package(
+    default_applicable_licenses = ["@heir//:license"],
+    default_visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "AddAndKeySwitchCountAnalysis",
+    srcs = ["AddAndKeySwitchCountAnalysis.cpp"],
+    hdrs = ["AddAndKeySwitchCountAnalysis.h"],
+    deps = [
+        "@heir//lib/Analysis/SecretnessAnalysis",
+        "@heir//lib/Dialect/Mgmt/IR:Dialect",
+        "@heir//lib/Dialect/Secret/IR:Dialect",
+        "@heir//lib/Dialect/TensorExt/IR:Dialect",
+        "@llvm-project//llvm:Support",
+        "@llvm-project//mlir:Analysis",
+        "@llvm-project//mlir:IR",
+        "@llvm-project//mlir:Support",
+    ],
+)

lib/Dialect/Mgmt/IR/MgmtAttributes.td

@@ -41,5 +41,33 @@ def Mgmt_MgmtAttr : Mgmt_Attr<"Mgmt", "mgmt"> {
   let assemblyFormat = "`<` struct(params) `>`";
 }
 
+def Mgmt_OpenfheParamsAttr : Mgmt_Attr<"OpenfheParams", "openfhe_params"> {
+  let summary = "Container attribute for some OpenFHE-specific parameters";
+  let description = [{
+    This attribute is used to store some OpenFHE-specific parameters.
+
+    The attribute is a struct with the following fields:
+      - `evalAddCount` : param for OpenFHE SetEvalAddCount
+      - `keySwitchCount` : param for OpenFHE SetKeySwitchCount
+
+    When this attribute presents, the lowering of openfhe pass
+    will use these parameters to set the corresponding OpenFHE
+    parameters.
+
+    It should be populated by --secret-with-mgmt-bgv before
+    going through the secret-to-bgv bgv-to-openfhe pass.
+
+    Example:
+    ```
+    #openfhe_params = #mgmt.openfhe_params<evalAddCount = 1, keySwitchCount = 1>
+    ```
+  }];
+
+  let parameters = (ins
+    "int": $evalAddCount,
+    "int": $keySwitchCount
+  );
+  let assemblyFormat = "`<` struct(params) `>`";
+}
 
 #endif  // LIB_DIALECT_MGMT_IR_MGMTATTRIBUTES_TD_

lib/Dialect/Mgmt/IR/MgmtDialect.td

@@ -18,6 +18,10 @@ def Mgmt_Dialect : Dialect {
     /// Name of the attribute holding MgmtAttr
     constexpr const static ::llvm::StringLiteral
         kArgMgmtAttrName = "mgmt.mgmt";
+
+    /// Name of the attribute holding OpenfheParamsAttr
+    constexpr const static ::llvm::StringLiteral
+        kArgOpenfheParamsAttrName = "mgmt.openfhe_params";
   }];
 
 

lib/Dialect/Openfhe/IR/OpenfheOps.td

@@ -74,7 +74,9 @@ def GenParamsOp : Openfhe_Op<"gen_params"> {
   let arguments = (ins
     I64Attr:$mulDepth,
     I64Attr:$plainMod,
-    BoolAttr:$insecure
+    BoolAttr:$insecure,
+    I64Attr:$evalAddCount,
+    I64Attr:$KeySwitchCount
   );
   let results = (outs Openfhe_CCParams:$params);
 }

lib/Dialect/Openfhe/Transforms/BUILD

@@ -26,6 +26,7 @@ cc_library(
     deps = [
         ":pass_inc_gen",
         "@heir//lib/Dialect/LWE/IR:Dialect",
+        "@heir//lib/Dialect/Mgmt/IR:Dialect",
         "@heir//lib/Dialect/ModArith/IR:Dialect",
         "@heir//lib/Dialect/Openfhe/IR:Dialect",
         "@heir//lib/Dialect/RNS/IR:Dialect",

lib/Dialect/Openfhe/Transforms/ConfigureCryptoContext.cpp

@@ -6,6 +6,7 @@
 #include <string>
 
 #include "lib/Dialect/LWE/IR/LWETypes.h"
+#include "lib/Dialect/Mgmt/IR/MgmtAttributes.h"
 #include "lib/Dialect/ModArith/IR/ModArithTypes.h"
 #include "lib/Dialect/Openfhe/IR/OpenfheOps.h"
 #include "lib/Dialect/Openfhe/IR/OpenfheTypes.h"
@@ -102,9 +103,21 @@ LogicalResult generateGenFunc(func::FuncOp op, const std::string &genFuncName,
     }
   }
 
+  // get evalAddCount/KeySwitchCount from func attribute, if present
+  int64_t evalAddCount = 0;
+  int64_t keySwitchCount = 0;
+  if (auto openfheParamAttr = mlir::dyn_cast<mgmt::OpenfheParamsAttr>(
+          op->getAttr(mgmt::MgmtDialect::kArgOpenfheParamsAttrName))) {
+    evalAddCount = openfheParamAttr.getEvalAddCount();
+    keySwitchCount = openfheParamAttr.getKeySwitchCount();
+    // remove the attribute after reading
+    op->removeAttr(mgmt::MgmtDialect::kArgOpenfheParamsAttrName);
+  }
+
   Type openfheParamsType = openfhe::CCParamsType::get(builder.getContext());
   Value ccParams = builder.create<openfhe::GenParamsOp>(
-      openfheParamsType, mulDepth, plainMod, insecure);
+      openfheParamsType, mulDepth, plainMod, insecure, evalAddCount,
+      keySwitchCount);
   Value cryptoContext = builder.create<openfhe::GenContextOp>(
       openfheContextType, ccParams,
       BoolAttr::get(builder.getContext(), hasBootstrapOp));