[X86] Add a Pass that builds a Condensed CFG for Load Value Injection (LVI) Gadgets

Adds a new data structure, ImmutableGraph, and uses RDF to find LVI gadgets and add them to a MachineGadgetGraph.

More specifically, a new X86 machine pass finds Load Value Injection (LVI) gadgets consisting of a load from memory (i.e., SOURCE), and any operation that may transmit the value loaded from memory over a covert channel, or use the value loaded from memory to determine a branch/call target (i.e., SINK).

Also adds a new target feature to X86: +lvi-load-hardening

The feature can be added via the clang CLI using -mlvi-hardening.

Differential Revision: https://reviews.llvm.org/D75936

13 files changed, 1187 insertions, 2 deletions

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index f57effa2c40e..391c895a453b 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -2267,6 +2267,10 @@ def mspeculative_load_hardening : Flag<["-"], "mspeculative-load-hardening">,
   Group<m_Group>, Flags<[CoreOption,CC1Option]>;
 def mno_speculative_load_hardening : Flag<["-"], "mno-speculative-load-hardening">,
   Group<m_Group>, Flags<[CoreOption]>;
+def mlvi_hardening : Flag<["-"], "mlvi-hardening">, Group<m_Group>, Flags<[CoreOption,DriverOption]>,
+  HelpText<"Enable all mitigations for Load Value Injection (LVI)">;
+def mno_lvi_hardening : Flag<["-"], "mno-lvi-hardening">, Group<m_Group>, Flags<[CoreOption,DriverOption]>,
+  HelpText<"Disable mitigations for Load Value Injection (LVI)">;
 def mlvi_cfi : Flag<["-"], "mlvi-cfi">, Group<m_Group>, Flags<[CoreOption,DriverOption]>,
   HelpText<"Enable only control-flow mitigations for Load Value Injection (LVI)">;
 def mno_lvi_cfi : Flag<["-"], "mno-lvi-cfi">, Group<m_Group>, Flags<[CoreOption,DriverOption]>,
diff --git a/clang/lib/Driver/ToolChains/Arch/X86.cpp b/clang/lib/Driver/ToolChains/Arch/X86.cpp
index 477e04485bf1..d170b7ac3a77 100644
--- a/clang/lib/Driver/ToolChains/Arch/X86.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/X86.cpp
@@ -173,7 +173,13 @@ void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
   }
 
   auto LVIOpt = clang::driver::options::ID::OPT_INVALID;
-  if (Args.hasFlag(options::OPT_mlvi_cfi, options::OPT_mno_lvi_cfi, false)) {
+  if (Args.hasFlag(options::OPT_mlvi_hardening, options::OPT_mno_lvi_hardening,
+                   false)) {
+    Features.push_back("+lvi-load-hardening");
+    Features.push_back("+lvi-cfi"); // load hardening implies CFI protection
+    LVIOpt = options::OPT_mlvi_hardening;
+  } else if (Args.hasFlag(options::OPT_mlvi_cfi, options::OPT_mno_lvi_cfi,
+                          false)) {
     Features.push_back("+lvi-cfi");
     LVIOpt = options::OPT_mlvi_cfi;
   }
diff --git a/clang/test/Driver/x86-target-features.c b/clang/test/Driver/x86-target-features.c
index 5c1668048f15..97e205013287 100644
--- a/clang/test/Driver/x86-target-features.c
+++ b/clang/test/Driver/x86-target-features.c
@@ -159,6 +159,11 @@
 // LVICFI: "-target-feature" "+lvi-cfi"
 // NO-LVICFI-NOT: lvi-cfi
 
+// RUN: %clang -target i386-linux-gnu -mlvi-hardening %s -### -o %t.o 2>&1 | FileCheck -check-prefix=LVIHARDENING %s
+// RUN: %clang -target i386-linux-gnu -mno-lvi-hardening %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-LVIHARDENING %s
+// LVIHARDENING: "-target-feature" "+lvi-load-hardening" "-target-feature" "+lvi-cfi"
+// NO-LVIHARDENING-NOT: lvi
+
 // RUN: %clang -target i386-linux-gnu -mwaitpkg %s -### -o %t.o 2>&1 | FileCheck -check-prefix=WAITPKG %s
 // RUN: %clang -target i386-linux-gnu -mno-waitpkg %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-WAITPKG %s
 // WAITPKG: "-target-feature" "+waitpkg"
diff --git a/llvm/lib/Target/X86/CMakeLists.txt b/llvm/lib/Target/X86/CMakeLists.txt
index 6b60aaf6d855..524e043c7df8 100644
--- a/llvm/lib/Target/X86/CMakeLists.txt
+++ b/llvm/lib/Target/X86/CMakeLists.txt
@@ -52,6 +52,7 @@ set(sources
   X86InstrInfo.cpp
   X86EvexToVex.cpp
   X86LegalizerInfo.cpp
+  X86LoadValueInjectionLoadHardening.cpp
   X86LoadValueInjectionRetHardening.cpp
   X86MCInstLower.cpp
   X86MachineFunctionInfo.cpp
diff --git a/llvm/lib/Target/X86/ImmutableGraph.h b/llvm/lib/Target/X86/ImmutableGraph.h
new file mode 100644
index 000000000000..80c9cf489ded
--- /dev/null
+++ b/llvm/lib/Target/X86/ImmutableGraph.h
@@ -0,0 +1,432 @@
+//==========-- ImmutableGraph.h - A fast DAG implementation ---------=========//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// Description: ImmutableGraph is a fast DAG implementation that cannot be
+/// modified, except by creating a new ImmutableGraph. ImmutableGraph is
+/// implemented as two arrays: one containing nodes, and one containing edges.
+/// The advantages to this implementation are two-fold:
+/// 1. Iteration and traversal operations should experience terrific caching
+///    performance.
+/// 2. Set representations and operations on nodes and edges become
+///    extraordinarily efficient. For instance, a set of edges is implemented as
+///    a bit vector, wherein each bit corresponds to one edge in the edge
+///    array. This implies a lower bound of 64x spacial improvement over, e.g.,
+///    an llvm::DenseSet or llvm::SmallSet. It also means that
+///    insert/erase/contains operations complete in negligible constant time:
+///    insert and erase require one load and one store, and contains requires
+///    just one load.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef IMMUTABLEGRAPH_H
+#define IMMUTABLEGRAPH_H
+
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <iterator>
+#include <utility>
+#include <vector>
+
+namespace llvm {
+
+template <typename _NodeValueT, typename _EdgeValueT, typename _SizeT = int>
+class ImmutableGraph {
+  using Traits = GraphTraits<ImmutableGraph<_NodeValueT, _EdgeValueT> *>;
+  template <typename> friend class ImmutableGraphBuilder;
+
+public:
+  using NodeValueT = _NodeValueT;
+  using EdgeValueT = _EdgeValueT;
+  using size_type = _SizeT;
+  class Node;
+  class Edge {
+    friend class ImmutableGraph;
+    template <typename> friend class ImmutableGraphBuilder;
+    friend Traits;
+
+    Node *__dest;
+    EdgeValueT __value;
+
+  public:
+    EdgeValueT &value() { return __value; }
+  };
+  class Node {
+    friend class ImmutableGraph;
+    template <typename> friend class ImmutableGraphBuilder;
+    friend Traits;
+
+    Edge *__edges;
+    NodeValueT __value;
+
+  public:
+    NodeValueT &value() { return __value; }
+  };
+
+protected:
+  ImmutableGraph(Node *Nodes, size_type NodesSize, Edge *Edges,
+                 size_type EdgesSize)
+      : __nodes{Nodes}, __nodes_size{NodesSize}, __edges{Edges},
+        __edges_size{EdgesSize} {}
+  ImmutableGraph(const ImmutableGraph &) = delete;
+  ImmutableGraph(ImmutableGraph &&) = delete;
+  ImmutableGraph &operator=(const ImmutableGraph &) = delete;
+  ImmutableGraph &operator=(ImmutableGraph &&) = delete;
+
+public:
+  ~ImmutableGraph() {
+    delete[] __edges;
+    delete[] __nodes;
+  }
+
+  Node *nodes_begin() const { return __nodes; }
+  Node *nodes_end() const { return __nodes + __nodes_size; }
+  Edge *edges_begin() const { return __edges; }
+  Edge *edges_end() const { return __edges + __edges_size; }
+  size_type nodes_size() const { return __nodes_size; }
+  size_type edges_size() const { return __edges_size; }
+  bool empty() const { return __nodes_size == 0; }
+
+  class NodeSet {
+    friend class iterator;
+
+    const ImmutableGraph &__g;
+    BitVector __v;
+
+  public:
+    NodeSet(const ImmutableGraph &G, bool ContainsAll = false)
+        : __g{G}, __v{static_cast<unsigned>(__g.nodes_size()), ContainsAll} {}
+    bool insert(Node *N) {
+      size_type Idx = std::distance(__g.nodes_begin(), N);
+      bool AlreadyExists = __v.test(Idx);
+      __v.set(Idx);
+      return !AlreadyExists;
+    }
+    void erase(Node *N) {
+      size_type Idx = std::distance(__g.nodes_begin(), N);
+      __v.reset(Idx);
+    }
+    bool contains(Node *N) const {
+      size_type Idx = std::distance(__g.nodes_begin(), N);
+      return __v.test(Idx);
+    }
+    void clear() { __v.reset(); }
+    size_type empty() const { return __v.none(); }
+    /// Return the number of elements in the set
+    size_type count() const { return __v.count(); }
+    /// Return the size of the set's domain
+    size_type size() const { return __v.size(); }
+    /// Set union
+    NodeSet &operator|=(const NodeSet &RHS) {
+      assert(&this->__g == &RHS.__g);
+      __v |= RHS.__v;
+      return *this;
+    }
+    /// Set intersection
+    NodeSet &operator&=(const NodeSet &RHS) {
+      assert(&this->__g == &RHS.__g);
+      __v &= RHS.__v;
+      return *this;
+    }
+    /// Set disjoint union
+    NodeSet &operator^=(const NodeSet &RHS) {
+      assert(&this->__g == &RHS.__g);
+      __v ^= RHS.__v;
+      return *this;
+    }
+
+    using index_iterator = typename BitVector::const_set_bits_iterator;
+    index_iterator index_begin() const { return __v.set_bits_begin(); }
+    index_iterator index_end() const { return __v.set_bits_end(); }
+    void set(size_type Idx) { __v.set(Idx); }
+    void reset(size_type Idx) { __v.reset(Idx); }
+
+    class iterator {
+      const NodeSet &__set;
+      size_type __current;
+
+      void advance() {
+        assert(__current != -1);
+        __current = __set.__v.find_next(__current);
+      }
+
+    public:
+      iterator(const NodeSet &Set, size_type Begin)
+          : __set{Set}, __current{Begin} {}
+      iterator operator++(int) {
+        iterator Tmp = *this;
+        advance();
+        return Tmp;
+      }
+      iterator &operator++() {
+        advance();
+        return *this;
+      }
+      Node *operator*() const {
+        assert(__current != -1);
+        return __set.__g.nodes_begin() + __current;
+      }
+      bool operator==(const iterator &other) const {
+        assert(&this->__set == &other.__set);
+        return this->__current == other.__current;
+      }
+      bool operator!=(const iterator &other) const { return !(*this == other); }
+    };
+
+    iterator begin() const { return iterator{*this, __v.find_first()}; }
+    iterator end() const { return iterator{*this, -1}; }
+  };
+
+  class EdgeSet {
+    const ImmutableGraph &__g;
+    BitVector __v;
+
+  public:
+    EdgeSet(const ImmutableGraph &G, bool ContainsAll = false)
+        : __g{G}, __v{static_cast<unsigned>(__g.edges_size()), ContainsAll} {}
+    bool insert(Edge *E) {
+      size_type Idx = std::distance(__g.edges_begin(), E);
+      bool AlreadyExists = __v.test(Idx);
+      __v.set(Idx);
+      return !AlreadyExists;
+    }
+    void erase(Edge *E) {
+      size_type Idx = std::distance(__g.edges_begin(), E);
+      __v.reset(Idx);
+    }
+    bool contains(Edge *E) const {
+      size_type Idx = std::distance(__g.edges_begin(), E);
+      return __v.test(Idx);
+    }
+    void clear() { __v.reset(); }
+    bool empty() const { return __v.none(); }
+    /// Return the number of elements in the set
+    size_type count() const { return __v.count(); }
+    /// Return the size of the set's domain
+    size_type size() const { return __v.size(); }
+    /// Set union
+    EdgeSet &operator|=(const EdgeSet &RHS) {
+      assert(&this->__g == &RHS.__g);
+      __v |= RHS.__v;
+      return *this;
+    }
+    /// Set intersection
+    EdgeSet &operator&=(const EdgeSet &RHS) {
+      assert(&this->__g == &RHS.__g);
+      __v &= RHS.__v;
+      return *this;
+    }
+    /// Set disjoint union
+    EdgeSet &operator^=(const EdgeSet &RHS) {
+      assert(&this->__g == &RHS.__g);
+      __v ^= RHS.__v;
+      return *this;
+    }
+
+    using index_iterator = typename BitVector::const_set_bits_iterator;
+    index_iterator index_begin() const { return __v.set_bits_begin(); }
+    index_iterator index_end() const { return __v.set_bits_end(); }
+    void set(size_type Idx) { __v.set(Idx); }
+    void reset(size_type Idx) { __v.reset(Idx); }
+
+    class iterator {
+      const EdgeSet &__set;
+      size_type __current;
+
+      void advance() {
+        assert(__current != -1);
+        __current = __set.__v.find_next(__current);
+      }
+
+    public:
+      iterator(const EdgeSet &Set, size_type Begin)
+          : __set{Set}, __current{Begin} {}
+      iterator operator++(int) {
+        iterator Tmp = *this;
+        advance();
+        return Tmp;
+      }
+      iterator &operator++() {
+        advance();
+        return *this;
+      }
+      Edge *operator*() const {
+        assert(__current != -1);
+        return __set.__g.edges_begin() + __current;
+      }
+      bool operator==(const iterator &other) const {
+        assert(&this->__set == &other.__set);
+        return this->__current == other.__current;
+      }
+      bool operator!=(const iterator &other) const { return !(*this == other); }
+    };
+
+    iterator begin() const { return iterator{*this, __v.find_first()}; }
+    iterator end() const { return iterator{*this, -1}; }
+  };
+
+private:
+  Node *__nodes;
+  size_type __nodes_size;
+  Edge *__edges;
+  size_type __edges_size;
+};
+
+template <typename GraphT> class ImmutableGraphBuilder {
+  using NodeValueT = typename GraphT::NodeValueT;
+  using EdgeValueT = typename GraphT::EdgeValueT;
+  static_assert(
+      std::is_base_of<ImmutableGraph<NodeValueT, EdgeValueT>, GraphT>::value,
+      "Template argument to ImmutableGraphBuilder must derive from "
+      "ImmutableGraph<>");
+  using size_type = typename GraphT::size_type;
+  using NodeSet = typename GraphT::NodeSet;
+  using Node = typename GraphT::Node;
+  using EdgeSet = typename GraphT::EdgeSet;
+  using Edge = typename GraphT::Edge;
+  using BuilderEdge = std::pair<EdgeValueT, size_type>;
+  using EdgeList = std::vector<BuilderEdge>;
+  using BuilderVertex = std::pair<NodeValueT, EdgeList>;
+  using VertexVec = std::vector<BuilderVertex>;
+
+public:
+  using NodeRef = size_type;
+
+  NodeRef addVertex(const NodeValueT &V) {
+    auto I = __adj_list.emplace(__adj_list.end(), V, EdgeList{});
+    return std::distance(__adj_list.begin(), I);
+  }
+
+  void addEdge(const EdgeValueT &E, NodeRef From, NodeRef To) {
+    __adj_list[From].second.emplace_back(E, To);
+  }
+
+  bool empty() const { return __adj_list.empty(); }
+
+  template <typename... ArgT> GraphT *get(ArgT &&... Args) {
+    size_type VertexSize = __adj_list.size(), EdgeSize = 0;
+    for (const auto &V : __adj_list) {
+      EdgeSize += V.second.size();
+    }
+    auto *VertexArray = new Node[VertexSize + 1 /* terminator node */];
+    auto *EdgeArray = new Edge[EdgeSize];
+    size_type VI = 0, EI = 0;
+    for (; VI < static_cast<size_type>(__adj_list.size()); ++VI) {
+      VertexArray[VI].__value = std::move(__adj_list[VI].first);
+      VertexArray[VI].__edges = &EdgeArray[EI];
+      auto NumEdges = static_cast<size_type>(__adj_list[VI].second.size());
+      if (NumEdges > 0) {
+        for (size_type VEI = 0; VEI < NumEdges; ++VEI, ++EI) {
+          auto &E = __adj_list[VI].second[VEI];
+          EdgeArray[EI].__value = std::move(E.first);
+          EdgeArray[EI].__dest = VertexArray + E.second;
+        }
+      }
+    }
+    assert(VI == VertexSize && EI == EdgeSize && "Gadget graph malformed");
+    VertexArray[VI].__edges = EdgeArray + EdgeSize; // terminator node
+    return new GraphT{VertexArray, VertexSize, EdgeArray, EdgeSize,
+                      std::forward<ArgT>(Args)...};
+  }
+
+  template <typename... ArgT>
+  static GraphT *trim(const GraphT &G, const NodeSet &TrimNodes,
+                      const EdgeSet &TrimEdges, ArgT &&... Args) {
+    size_type NewVertexSize = TrimNodes.size() - TrimNodes.count();
+    size_type NewEdgeSize = TrimEdges.size() - TrimEdges.count();
+    auto *NewVertexArray = new Node[NewVertexSize + 1 /* terminator node */];
+    auto *NewEdgeArray = new Edge[NewEdgeSize];
+    size_type TrimmedNodesSoFar = 0,
+              *TrimmedNodes = new size_type[TrimNodes.size()];
+    for (size_type I = 0; I < TrimNodes.size(); ++I) {
+      TrimmedNodes[I] = TrimmedNodesSoFar;
+      if (TrimNodes.contains(G.nodes_begin() + I))
+        ++TrimmedNodesSoFar;
+    }
+    size_type VertexI = 0, EdgeI = 0;
+    for (Node *NI = G.nodes_begin(), *NE = G.nodes_end(); NI != NE; ++NI) {
+      if (TrimNodes.contains(NI))
+        continue;
+      size_type NewNumEdges =
+          static_cast<int>((NI + 1)->__edges - NI->__edges) > 0
+              ? std::count_if(
+                    NI->__edges, (NI + 1)->__edges,
+                    [&TrimEdges](Edge &E) { return !TrimEdges.contains(&E); })
+              : 0;
+      NewVertexArray[VertexI].__value = NI->__value;
+      NewVertexArray[VertexI].__edges = &NewEdgeArray[EdgeI];
+      if (NewNumEdges > 0) {
+        for (Edge *EI = NI->__edges, *EE = (NI + 1)->__edges; EI != EE; ++EI) {
+          if (TrimEdges.contains(EI))
+            continue;
+          NewEdgeArray[EdgeI].__value = EI->__value;
+          size_type DestIdx = std::distance(G.nodes_begin(), EI->__dest);
+          size_type NewIdx = DestIdx - TrimmedNodes[DestIdx];
+          assert(NewIdx < NewVertexSize);
+          NewEdgeArray[EdgeI].__dest = NewVertexArray + NewIdx;
+          ++EdgeI;
+        }
+      }
+      ++VertexI;
+    }
+    delete[] TrimmedNodes;
+    assert(VertexI == NewVertexSize && EdgeI == NewEdgeSize &&
+           "Gadget graph malformed");
+    NewVertexArray[VertexI].__edges = NewEdgeArray + NewEdgeSize;
+    return new GraphT{NewVertexArray, NewVertexSize, NewEdgeArray, NewEdgeSize,
+                      std::forward<ArgT>(Args)...};
+  }
+
+private:
+  VertexVec __adj_list;
+};
+
+template <typename NodeValueT, typename EdgeValueT>
+struct GraphTraits<ImmutableGraph<NodeValueT, EdgeValueT> *> {
+  using GraphT = ImmutableGraph<NodeValueT, EdgeValueT>;
+  using NodeRef = typename GraphT::Node *;
+  using EdgeRef = typename GraphT::Edge &;
+
+  static NodeRef edge_dest(EdgeRef E) { return E.__dest; }
+  using ChildIteratorType =
+      mapped_iterator<typename GraphT::Edge *, decltype(&edge_dest)>;
+
+  static NodeRef getEntryNode(GraphT *G) { return G->nodes_begin(); }
+  static ChildIteratorType child_begin(NodeRef N) {
+    return {N->__edges, &edge_dest};
+  }
+  static ChildIteratorType child_end(NodeRef N) {
+    return {(N + 1)->__edges, &edge_dest};
+  }
+
+  static NodeRef getNode(typename GraphT::Node &N) { return NodeRef{&N}; }
+  using nodes_iterator =
+      mapped_iterator<typename GraphT::Node *, decltype(&getNode)>;
+  static nodes_iterator nodes_begin(GraphT *G) {
+    return {G->nodes_begin(), &getNode};
+  }
+  static nodes_iterator nodes_end(GraphT *G) {
+    return {G->nodes_end(), &getNode};
+  }
+
+  using ChildEdgeIteratorType = typename GraphT::Edge *;
+
+  static ChildEdgeIteratorType child_edge_begin(NodeRef N) {
+    return N->__edges;
+  }
+  static ChildEdgeIteratorType child_edge_end(NodeRef N) {
+    return (N + 1)->__edges;
+  }
+  static typename GraphT::size_type size(GraphT *G) { return G->nodes_size(); }
+};
+
+} // end namespace llvm
+
+#endif // IMMUTABLEGRAPH_H
diff --git a/llvm/lib/Target/X86/X86.h b/llvm/lib/Target/X86/X86.h
index 06b8ae8754aa..39b2f814defa 100644
--- a/llvm/lib/Target/X86/X86.h
+++ b/llvm/lib/Target/X86/X86.h
@@ -133,6 +133,7 @@ InstructionSelector *createX86InstructionSelector(const X86TargetMachine &TM,
                                                   X86Subtarget &,
                                                   X86RegisterBankInfo &);
 
+FunctionPass *createX86LoadValueInjectionLoadHardeningPass();
 FunctionPass *createX86LoadValueInjectionRetHardeningPass();
 FunctionPass *createX86SpeculativeLoadHardeningPass();
 
@@ -149,6 +150,7 @@ void initializeX86DomainReassignmentPass(PassRegistry &);
 void initializeX86ExecutionDomainFixPass(PassRegistry &);
 void initializeX86ExpandPseudoPass(PassRegistry &);
 void initializeX86FlagsCopyLoweringPassPass(PassRegistry &);
+void initializeX86LoadValueInjectionLoadHardeningPassPass(PassRegistry &);
 void initializeX86LoadValueInjectionRetHardeningPassPass(PassRegistry &);
 void initializeX86OptimizeLEAPassPass(PassRegistry &);
 void initializeX86SpeculativeLoadHardeningPassPass(PassRegistry &);
diff --git a/llvm/lib/Target/X86/X86.td b/llvm/lib/Target/X86/X86.td
index edc474825760..bb8952f54e3a 100644
--- a/llvm/lib/Target/X86/X86.td
+++ b/llvm/lib/Target/X86/X86.td
@@ -435,6 +435,13 @@ def FeatureLVIControlFlowIntegrity
           "LFENCE instruction to serialize control flow. Also decompose RET "
           "instructions into a POP+LFENCE+JMP sequence.">;
 
+// Mitigate LVI attacks against data loads
+def FeatureLVILoadHardening
+    : SubtargetFeature<
+          "lvi-load-hardening", "UseLVILoadHardening", "true",
+          "Insert LFENCE instructions to prevent data speculatively injected "
+          "into loads from being used maliciously.">;
+
 // Direct Move instructions.
 def FeatureMOVDIRI  : SubtargetFeature<"movdiri", "HasMOVDIRI", "true",
                                        "Support movdiri instruction">;
diff --git a/llvm/lib/Target/X86/X86LoadValueInjectionLoadHardening.cpp b/llvm/lib/Target/X86/X86LoadValueInjectionLoadHardening.cpp
new file mode 100644
index 000000000000..7c027e5fca67
--- /dev/null
+++ b/llvm/lib/Target/X86/X86LoadValueInjectionLoadHardening.cpp
@@ -0,0 +1,586 @@
+//==-- X86LoadValueInjectionLoadHardening.cpp - LVI load hardening for x86 --=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// Description: This pass finds Load Value Injection (LVI) gadgets consisting
+/// of a load from memory (i.e., SOURCE), and any operation that may transmit
+/// the value loaded from memory over a covert channel, or use the value loaded
+/// from memory to determine a branch/call target (i.e., SINK).
+///
+//===----------------------------------------------------------------------===//
+
+#include "ImmutableGraph.h"
+#include "X86.h"
+#include "X86Subtarget.h"
+#include "X86TargetMachine.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineDominanceFrontier.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/RDFGraph.h"
+#include "llvm/CodeGen/RDFLiveness.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DOTGraphTraits.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/GraphWriter.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+#define PASS_KEY "x86-lvi-load"
+#define DEBUG_TYPE PASS_KEY
+
+STATISTIC(NumFunctionsConsidered, "Number of functions analyzed");
+STATISTIC(NumFunctionsMitigated, "Number of functions for which mitigations "
+                                 "were deployed");
+STATISTIC(NumGadgets, "Number of LVI gadgets detected during analysis");
+
+static cl::opt<bool> NoConditionalBranches(
+    PASS_KEY "-no-cbranch",
+    cl::desc("Don't treat conditional branches as disclosure gadgets. This "
+             "may improve performance, at the cost of security."),
+    cl::init(false), cl::Hidden);
+
+static cl::opt<bool> EmitDot(
+    PASS_KEY "-dot",
+    cl::desc(
+        "For each function, emit a dot graph depicting potential LVI gadgets"),
+    cl::init(false), cl::Hidden);
+
+static cl::opt<bool> EmitDotOnly(
+    PASS_KEY "-dot-only",
+    cl::desc("For each function, emit a dot graph depicting potential LVI "
+             "gadgets, and do not insert any fences"),
+    cl::init(false), cl::Hidden);
+
+static cl::opt<bool> EmitDotVerify(
+    PASS_KEY "-dot-verify",
+    cl::desc("For each function, emit a dot graph to stdout depicting "
+             "potential LVI gadgets, used for testing purposes only"),
+    cl::init(false), cl::Hidden);
+
+static cl::opt<bool> NoFixedLoads(
+    PASS_KEY "-no-fixed",
+    cl::desc("Don't mitigate RIP-relative or RSP-relative loads. This "
+             "may improve performance, at the cost of security."),
+    cl::init(false), cl::Hidden);
+
+#define ARG_NODE nullptr
+#define GADGET_EDGE ((int)(-1))
+#define WEIGHT(EdgeValue) ((double)(2 * (EdgeValue) + 1))
+
+namespace {
+
+class X86LoadValueInjectionLoadHardeningPass : public MachineFunctionPass {
+public:
+  X86LoadValueInjectionLoadHardeningPass() : MachineFunctionPass(ID) {}
+
+  StringRef getPassName() const override {
+    return "X86 Load Value Injection (LVI) Load Hardening";
+  }
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  static char ID;
+
+private:
+  struct MachineGadgetGraph : ImmutableGraph<MachineInstr *, int> {
+    using GraphT = ImmutableGraph<MachineInstr *, int>;
+    using Node = typename GraphT::Node;
+    using Edge = typename GraphT::Edge;
+    using size_type = typename GraphT::size_type;
+    MachineGadgetGraph(Node *Nodes, size_type NodesSize, Edge *Edges,
+                       size_type EdgesSize, int NumFences = 0,
+                       int NumGadgets = 0)
+        : GraphT{Nodes, NodesSize, Edges, EdgesSize}, NumFences{NumFences},
+          NumGadgets{NumGadgets} {}
+    MachineFunction &getMF() { // FIXME: This function should be cleaner
+      for (Node *NI = nodes_begin(), *const NE = nodes_end(); NI != NE; ++NI) {
+        if (NI->value()) {
+          return *NI->value()->getMF();
+        }
+      }
+      llvm_unreachable("Could not find a valid node");
+    }
+    static inline bool isCFGEdge(Edge &E) { return E.value() != GADGET_EDGE; }
+    static inline bool isGadgetEdge(Edge &E) {
+      return E.value() == GADGET_EDGE;
+    }
+    int NumFences;
+    int NumGadgets;
+  };
+  friend struct llvm::DOTGraphTraits<MachineGadgetGraph *>;
+  using GTraits = llvm::GraphTraits<MachineGadgetGraph *>;
+  using GraphBuilder = ImmutableGraphBuilder<MachineGadgetGraph>;
+  using EdgeSet = MachineGadgetGraph::EdgeSet;
+  using Gadget = std::pair<MachineInstr *, MachineInstr *>;
+
+  const X86Subtarget *STI;
+  const TargetInstrInfo *TII;
+  const TargetRegisterInfo *TRI;
+
+  int hardenLoads(MachineFunction &MF, bool Fixed) const;
+  std::unique_ptr<MachineGadgetGraph>
+  getGadgetGraph(MachineFunction &MF, const MachineLoopInfo &MLI,
+                 const MachineDominatorTree &MDT,
+                 const MachineDominanceFrontier &MDF, bool FixedLoads) const;
+
+  bool instrUsesRegToAccessMemory(const MachineInstr &I, unsigned Reg) const;
+  bool instrUsesRegToBranch(const MachineInstr &I, unsigned Reg) const;
+  template <unsigned K> bool hasLoadFrom(const MachineInstr &MI) const;
+  bool instrAccessesStackSlot(const MachineInstr &MI) const;
+  bool instrAccessesConstantPool(const MachineInstr &MI) const;
+  bool instrAccessesGOT(const MachineInstr &MI) const;
+  inline bool instrIsFixedAccess(const MachineInstr &MI) const {
+    return instrAccessesConstantPool(MI) || instrAccessesStackSlot(MI) ||
+           instrAccessesGOT(MI);
+  }
+  inline bool isFence(const MachineInstr *MI) const {
+    return MI && (MI->getOpcode() == X86::LFENCE ||
+                  (STI->useLVIControlFlowIntegrity() && MI->isCall()));
+  }
+};
+
+} // end anonymous namespace
+
+namespace llvm {
+
+template <>
+struct GraphTraits<X86LoadValueInjectionLoadHardeningPass::MachineGadgetGraph *>
+    : GraphTraits<ImmutableGraph<MachineInstr *, int> *> {};
+
+template <>
+struct DOTGraphTraits<
+    X86LoadValueInjectionLoadHardeningPass::MachineGadgetGraph *>
+    : DefaultDOTGraphTraits {
+  using GraphType = X86LoadValueInjectionLoadHardeningPass::MachineGadgetGraph;
+  using Traits = X86LoadValueInjectionLoadHardeningPass::GTraits;
+  using NodeRef = typename Traits::NodeRef;
+  using EdgeRef = typename Traits::EdgeRef;
+  using ChildIteratorType = typename Traits::ChildIteratorType;
+  using ChildEdgeIteratorType = typename Traits::ChildEdgeIteratorType;
+
+  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
+
+  static std::string getGraphName(GraphType *G) {
+    std::string GraphName{"Speculative gadgets for \""};
+    GraphName += G->getMF().getName();
+    GraphName += "\" function";
+    return GraphName;
+  }
+
+  std::string getNodeLabel(NodeRef Node, GraphType *) {
+    std::string str;
+    raw_string_ostream str_stream{str};
+    if (Node->value() == ARG_NODE)
+      return "ARGS";
+    str_stream << *Node->value();
+    return str_stream.str();
+  }
+
+  static std::string getNodeAttributes(NodeRef Node, GraphType *) {
+    MachineInstr *MI = Node->value();
+    if (MI == ARG_NODE)
+      return "color = blue";
+    else if (MI->getOpcode() == X86::LFENCE)
+      return "color = green";
+    else
+      return "";
+  }
+
+  static std::string getEdgeAttributes(NodeRef, ChildIteratorType E,
+                                       GraphType *) {
+    int EdgeVal = (*E.getCurrent()).value();
+    return EdgeVal >= 0 ? "label = " + std::to_string(EdgeVal)
+                        : "color = red, style = \"dashed\"";
+  }
+};
+
+} // end namespace llvm
+
+char X86LoadValueInjectionLoadHardeningPass::ID = 0;
+
+void X86LoadValueInjectionLoadHardeningPass::getAnalysisUsage(
+    AnalysisUsage &AU) const {
+  MachineFunctionPass::getAnalysisUsage(AU);
+  AU.addRequired<MachineLoopInfo>();
+  AU.addRequired<MachineDominatorTree>();
+  AU.addRequired<MachineDominanceFrontier>();
+  AU.setPreservesCFG();
+}
+
+bool X86LoadValueInjectionLoadHardeningPass::runOnMachineFunction(
+    MachineFunction &MF) {
+  LLVM_DEBUG(dbgs() << "***** " << getPassName() << " : " << MF.getName()
+                    << " *****\n");
+  STI = &MF.getSubtarget<X86Subtarget>();
+  if (!STI->useLVILoadHardening() || !STI->is64Bit())
+    return false; // FIXME: support 32-bit
+
+  // Don't skip functions with the "optnone" attr but participate in opt-bisect.
+  const Function &F = MF.getFunction();
+  if (!F.hasOptNone() && skipFunction(F))
+    return false;
+
+  ++NumFunctionsConsidered;
+  TII = STI->getInstrInfo();
+  TRI = STI->getRegisterInfo();
+  LLVM_DEBUG(dbgs() << "Hardening data-dependent loads...\n");
+  hardenLoads(MF, false);
+  LLVM_DEBUG(dbgs() << "Hardening data-dependent loads... Done\n");
+  if (!NoFixedLoads) {
+    LLVM_DEBUG(dbgs() << "Hardening fixed loads...\n");
+    hardenLoads(MF, true);
+    LLVM_DEBUG(dbgs() << "Hardening fixed loads... Done\n");
+  }
+  return false;
+}
+
+// Apply the mitigation to `MF`, return the number of fences inserted.
+// If `FixedLoads` is `true`, then the mitigation will be applied to fixed
+// loads; otherwise, mitigation will be applied to non-fixed loads.
+int X86LoadValueInjectionLoadHardeningPass::hardenLoads(MachineFunction &MF,
+                                                        bool FixedLoads) const {
+  LLVM_DEBUG(dbgs() << "Building gadget graph...\n");
+  const auto &MLI = getAnalysis<MachineLoopInfo>();
+  const auto &MDT = getAnalysis<MachineDominatorTree>();
+  const auto &MDF = getAnalysis<MachineDominanceFrontier>();
+  std::unique_ptr<MachineGadgetGraph> Graph =
+      getGadgetGraph(MF, MLI, MDT, MDF, FixedLoads);
+  LLVM_DEBUG(dbgs() << "Building gadget graph... Done\n");
+  if (Graph == nullptr)
+    return 0; // didn't find any gadgets
+
+  if (EmitDotVerify) {
+    WriteGraph(outs(), Graph.get());
+    return 0;
+  }
+
+  if (EmitDot || EmitDotOnly) {
+    LLVM_DEBUG(dbgs() << "Emitting gadget graph...\n");
+    std::error_code FileError;
+    std::string FileName = "lvi.";
+    if (FixedLoads)
+      FileName += "fixed.";
+    FileName += Graph->getMF().getName();
+    FileName += ".dot";
+    raw_fd_ostream FileOut(FileName, FileError);
+    if (FileError)
+      errs() << FileError.message();
+    WriteGraph(FileOut, Graph.get());
+    FileOut.close();
+    LLVM_DEBUG(dbgs() << "Emitting gadget graph... Done\n");
+    if (EmitDotOnly)
+      return 0;
+  }
+
+  return 0;
+}
+
+std::unique_ptr<X86LoadValueInjectionLoadHardeningPass::MachineGadgetGraph>
+X86LoadValueInjectionLoadHardeningPass::getGadgetGraph(
+    MachineFunction &MF, const MachineLoopInfo &MLI,
+    const MachineDominatorTree &MDT, const MachineDominanceFrontier &MDF,
+    bool FixedLoads) const {
+  using namespace rdf;
+
+  // Build the Register Dataflow Graph using the RDF framework
+  TargetOperandInfo TOI{*TII};
+  DataFlowGraph DFG{MF, *TII, *TRI, MDT, MDF, TOI};
+  DFG.build();
+  Liveness L{MF.getRegInfo(), DFG};
+  L.computePhiInfo();
+
+  GraphBuilder Builder;
+  using GraphIter = typename GraphBuilder::NodeRef;
+  DenseMap<MachineInstr *, GraphIter> NodeMap;
+  int FenceCount = 0;
+  auto MaybeAddNode = [&NodeMap, &Builder](MachineInstr *MI) {
+    auto Ref = NodeMap.find(MI);
+    if (Ref == NodeMap.end()) {
+      auto I = Builder.addVertex(MI);
+      NodeMap[MI] = I;
+      return std::pair<GraphIter, bool>{I, true};
+    } else {
+      return std::pair<GraphIter, bool>{Ref->getSecond(), false};
+    }
+  };
+
+  // Analyze all machine instructions to find gadgets and LFENCEs, adding
+  // each interesting value to `Nodes`
+  DenseSet<std::pair<GraphIter, GraphIter>> GadgetEdgeSet;
+  auto AnalyzeDef = [&](NodeAddr<DefNode *> Def) {
+    MachineInstr *MI = Def.Addr->getFlags() & NodeAttrs::PhiRef
+                           ? ARG_NODE
+                           : Def.Addr->getOp().getParent();
+    auto AnalyzeUse = [&](NodeAddr<UseNode *> Use) {
+      assert(!(Use.Addr->getFlags() & NodeAttrs::PhiRef));
+      MachineOperand &UseMO = Use.Addr->getOp();
+      MachineInstr &UseMI = *UseMO.getParent();
+      assert(UseMO.isReg());
+      // We naively assume that an instruction propagates any loaded Uses
+      // to all Defs, unless the instruction is a call
+      if (UseMI.isCall())
+        return false;
+      if (instrUsesRegToAccessMemory(UseMI, UseMO.getReg()) ||
+          (!NoConditionalBranches &&
+           instrUsesRegToBranch(UseMI, UseMO.getReg()))) { // found a gadget!
+        // add the root of this chain
+        auto GadgetBegin = MaybeAddNode(MI);
+        // and the instruction that (transitively) discloses the root
+        auto GadgetEnd = MaybeAddNode(&UseMI);
+        if (GadgetEdgeSet.insert({GadgetBegin.first, GadgetEnd.first}).second)
+          Builder.addEdge(GADGET_EDGE, GadgetBegin.first, GadgetEnd.first);
+        if (UseMI.mayLoad()) // FIXME: This should be more precise
+          return false;      // stop traversing further uses of `Reg`
+      }
+      return true;
+    };
+    SmallSet<NodeId, 8> NodesVisited;
+    std::function<void(NodeAddr<DefNode *>)> AnalyzeDefUseChain =
+        [&](NodeAddr<DefNode *> Def) {
+          if (Def.Addr->getAttrs() & NodeAttrs::Dead)
+            return;
+          RegisterRef DefReg = DFG.getPRI().normalize(Def.Addr->getRegRef(DFG));
+          NodeList Uses;
+          for (auto UseID : L.getAllReachedUses(DefReg, Def)) {
+            auto Use = DFG.addr<UseNode *>(UseID);
+            if (Use.Addr->getFlags() & NodeAttrs::PhiRef) { // phi node
+              NodeAddr<PhiNode *> Phi = Use.Addr->getOwner(DFG);
+              for (auto I : L.getRealUses(Phi.Id)) {
+                if (DFG.getPRI().alias(RegisterRef(I.first), DefReg)) {
+                  for (auto UA : I.second) {
+                    auto PhiUse = DFG.addr<UseNode *>(UA.first);
+                    Uses.push_back(PhiUse);
+                  }
+                }
+              }
+            } else { // not a phi node
+              Uses.push_back(Use);
+            }
+          }
+          for (auto N : Uses) {
+            NodeAddr<UseNode *> Use{N};
+            if (NodesVisited.insert(Use.Id).second && AnalyzeUse(Use)) {
+              NodeAddr<InstrNode *> Owner{Use.Addr->getOwner(DFG)};
+              NodeList Defs = Owner.Addr->members_if(DataFlowGraph::IsDef, DFG);
+              std::for_each(Defs.begin(), Defs.end(), AnalyzeDefUseChain);
+            }
+          }
+        };
+    AnalyzeDefUseChain(Def);
+  };
+
+  LLVM_DEBUG(dbgs() << "Analyzing def-use chains to find gadgets\n");
+  // Analyze function arguments
+  if (!FixedLoads) { // only need to analyze function args once
+    NodeAddr<BlockNode *> EntryBlock = DFG.getFunc().Addr->getEntryBlock(DFG);
+    for (NodeAddr<PhiNode *> ArgPhi :
+         EntryBlock.Addr->members_if(DataFlowGraph::IsPhi, DFG)) {
+      NodeList Defs = ArgPhi.Addr->members_if(DataFlowGraph::IsDef, DFG);
+      std::for_each(Defs.begin(), Defs.end(), AnalyzeDef);
+    }
+  }
+  // Analyze every instruction in MF
+  for (NodeAddr<BlockNode *> BA : DFG.getFunc().Addr->members(DFG)) {
+    for (NodeAddr<StmtNode *> SA :
+         BA.Addr->members_if(DataFlowGraph::IsCode<NodeAttrs::Stmt>, DFG)) {
+      MachineInstr *MI = SA.Addr->getCode();
+      if (isFence(MI)) {
+        MaybeAddNode(MI);
+        ++FenceCount;
+      } else if (MI->mayLoad() && ((FixedLoads && instrIsFixedAccess(*MI)) ||
+                                   (!FixedLoads && !instrIsFixedAccess(*MI)))) {
+        NodeList Defs = SA.Addr->members_if(DataFlowGraph::IsDef, DFG);
+        std::for_each(Defs.begin(), Defs.end(), AnalyzeDef);
+      }
+    }
+  }
+  int GadgetCount = static_cast<int>(GadgetEdgeSet.size());
+  LLVM_DEBUG(dbgs() << "Found " << FenceCount << " fences\n");
+  LLVM_DEBUG(dbgs() << "Found " << GadgetCount << " gadgets\n");
+  if (GadgetCount == 0)
+    return nullptr;
+  NumGadgets += GadgetCount;
+
+  // Traverse CFG to build the rest of the graph
+  SmallSet<MachineBasicBlock *, 8> BlocksVisited;
+  std::function<void(MachineBasicBlock *, GraphIter, unsigned)> TraverseCFG =
+      [&](MachineBasicBlock *MBB, GraphIter GI, unsigned ParentDepth) {
+        unsigned LoopDepth = MLI.getLoopDepth(MBB);
+        if (!MBB->empty()) {
+          // Always add the first instruction in each block
+          auto NI = MBB->begin();
+          auto BeginBB = MaybeAddNode(&*NI);
+          Builder.addEdge(ParentDepth, GI, BeginBB.first);
+          if (!BlocksVisited.insert(MBB).second)
+            return;
+
+          // Add any instructions within the block that are gadget components
+          GI = BeginBB.first;
+          while (++NI != MBB->end()) {
+            auto Ref = NodeMap.find(&*NI);
+            if (Ref != NodeMap.end()) {
+              Builder.addEdge(LoopDepth, GI, Ref->getSecond());
+              GI = Ref->getSecond();
+            }
+          }
+
+          // Always add the terminator instruction, if one exists
+          auto T = MBB->getFirstTerminator();
+          if (T != MBB->end()) {
+            auto EndBB = MaybeAddNode(&*T);
+            if (EndBB.second)
+              Builder.addEdge(LoopDepth, GI, EndBB.first);
+            GI = EndBB.first;
+          }
+        }
+        for (MachineBasicBlock *Succ : MBB->successors())
+          TraverseCFG(Succ, GI, LoopDepth);
+      };
+  // ARG_NODE is a pseudo-instruction that represents MF args in the GadgetGraph
+  GraphIter ArgNode = MaybeAddNode(ARG_NODE).first;
+  TraverseCFG(&MF.front(), ArgNode, 0);
+  std::unique_ptr<MachineGadgetGraph> G{Builder.get(FenceCount, GadgetCount)};
+  LLVM_DEBUG(dbgs() << "Found " << GTraits::size(G.get()) << " nodes\n");
+  return G;
+}
+
+bool X86LoadValueInjectionLoadHardeningPass::instrUsesRegToAccessMemory(
+    const MachineInstr &MI, unsigned Reg) const {
+  if (!MI.mayLoadOrStore() || MI.getOpcode() == X86::MFENCE ||
+      MI.getOpcode() == X86::SFENCE || MI.getOpcode() == X86::LFENCE)
+    return false;
+
+  // FIXME: This does not handle pseudo loading instruction like TCRETURN*
+  const MCInstrDesc &Desc = MI.getDesc();
+  int MemRefBeginIdx = X86II::getMemoryOperandNo(Desc.TSFlags);
+  if (MemRefBeginIdx < 0) {
+    LLVM_DEBUG(dbgs() << "Warning: unable to obtain memory operand for loading "
+                         "instruction:\n";
+               MI.print(dbgs()); dbgs() << '\n';);
+    return false;
+  }
+  MemRefBeginIdx += X86II::getOperandBias(Desc);
+
+  const MachineOperand &BaseMO =
+      MI.getOperand(MemRefBeginIdx + X86::AddrBaseReg);
+  const MachineOperand &IndexMO =
+      MI.getOperand(MemRefBeginIdx + X86::AddrIndexReg);
+  return (BaseMO.isReg() && BaseMO.getReg() != X86::NoRegister &&
+          TRI->regsOverlap(BaseMO.getReg(), Reg)) ||
+         (IndexMO.isReg() && IndexMO.getReg() != X86::NoRegister &&
+          TRI->regsOverlap(IndexMO.getReg(), Reg));
+}
+
+bool X86LoadValueInjectionLoadHardeningPass::instrUsesRegToBranch(
+    const MachineInstr &MI, unsigned Reg) const {
+  if (!MI.isConditionalBranch())
+    return false;
+  for (const MachineOperand &Use : MI.uses())
+    if (Use.isReg() && Use.getReg() == Reg)
+      return true;
+  return false;
+}
+
+template <unsigned K>
+bool X86LoadValueInjectionLoadHardeningPass::hasLoadFrom(
+    const MachineInstr &MI) const {
+  for (auto &MMO : MI.memoperands()) {
+    const PseudoSourceValue *PSV = MMO->getPseudoValue();
+    if (PSV && PSV->kind() == K && MMO->isLoad())
+      return true;
+  }
+  return false;
+}
+
+bool X86LoadValueInjectionLoadHardeningPass::instrAccessesStackSlot(
+    const MachineInstr &MI) const {
+  // Check the PSV first
+  if (hasLoadFrom<PseudoSourceValue::PSVKind::FixedStack>(MI))
+    return true;
+  // Some loads are not marked with a PSV, so we always need to double check
+  const MCInstrDesc &Desc = MI.getDesc();
+  int MemRefBeginIdx = X86II::getMemoryOperandNo(Desc.TSFlags);
+  if (MemRefBeginIdx < 0)
+    return false;
+  MemRefBeginIdx += X86II::getOperandBias(Desc);
+  return MI.getOperand(MemRefBeginIdx + X86::AddrBaseReg).isFI() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrScaleAmt).isImm() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrIndexReg).isReg() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrDisp).isImm() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrScaleAmt).getImm() == 1 &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrIndexReg).getReg() ==
+             X86::NoRegister &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrDisp).getImm() == 0;
+}
+
+bool X86LoadValueInjectionLoadHardeningPass::instrAccessesConstantPool(
+    const MachineInstr &MI) const {
+  if (hasLoadFrom<PseudoSourceValue::PSVKind::ConstantPool>(MI))
+    return true;
+  const MCInstrDesc &Desc = MI.getDesc();
+  int MemRefBeginIdx = X86II::getMemoryOperandNo(Desc.TSFlags);
+  if (MemRefBeginIdx < 0)
+    return false;
+  MemRefBeginIdx += X86II::getOperandBias(Desc);
+  return MI.getOperand(MemRefBeginIdx + X86::AddrBaseReg).isReg() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrScaleAmt).isImm() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrIndexReg).isReg() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrDisp).isCPI() &&
+         (MI.getOperand(MemRefBeginIdx + X86::AddrBaseReg).getReg() ==
+              X86::RIP ||
+          MI.getOperand(MemRefBeginIdx + X86::AddrBaseReg).getReg() ==
+              X86::NoRegister) &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrScaleAmt).getImm() == 1 &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrIndexReg).getReg() ==
+             X86::NoRegister;
+}
+
+bool X86LoadValueInjectionLoadHardeningPass::instrAccessesGOT(
+    const MachineInstr &MI) const {
+  if (hasLoadFrom<PseudoSourceValue::PSVKind::GOT>(MI))
+    return true;
+  const MCInstrDesc &Desc = MI.getDesc();
+  int MemRefBeginIdx = X86II::getMemoryOperandNo(Desc.TSFlags);
+  if (MemRefBeginIdx < 0)
+    return false;
+  MemRefBeginIdx += X86II::getOperandBias(Desc);
+  return MI.getOperand(MemRefBeginIdx + X86::AddrBaseReg).isReg() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrScaleAmt).isImm() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrIndexReg).isReg() &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrDisp).getTargetFlags() ==
+             X86II::MO_GOTPCREL &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrBaseReg).getReg() ==
+             X86::RIP &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrScaleAmt).getImm() == 1 &&
+         MI.getOperand(MemRefBeginIdx + X86::AddrIndexReg).getReg() ==
+             X86::NoRegister;
+}
+
+INITIALIZE_PASS_BEGIN(X86LoadValueInjectionLoadHardeningPass, PASS_KEY,
+                      "X86 LVI load hardening", false, false)
+INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
+INITIALIZE_PASS_DEPENDENCY(MachineDominanceFrontier)
+INITIALIZE_PASS_END(X86LoadValueInjectionLoadHardeningPass, PASS_KEY,
+                    "X86 LVI load hardening", false, false)
+
+FunctionPass *llvm::createX86LoadValueInjectionLoadHardeningPass() {
+  return new X86LoadValueInjectionLoadHardeningPass();
+}
diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index eb5c293e5cbf..af5153243c8b 100644
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -427,6 +427,10 @@ protected:
   /// POP+LFENCE+JMP sequence.
   bool UseLVIControlFlowIntegrity = false;
 
+  /// Insert LFENCE instructions to prevent data speculatively injected into
+  /// loads from being used maliciously.
+  bool UseLVILoadHardening = false;
+
   /// Use software floating point for code generation.
   bool UseSoftFloat = false;
 
@@ -727,6 +731,7 @@ public:
   bool preferMaskRegisters() const { return PreferMaskRegisters; }
   bool useGLMDivSqrtCosts() const { return UseGLMDivSqrtCosts; }
   bool useLVIControlFlowIntegrity() const { return UseLVIControlFlowIntegrity; }
+  bool useLVILoadHardening() const { return UseLVILoadHardening; }
 
   unsigned getPreferVectorWidth() const { return PreferVectorWidth; }
   unsigned getRequiredVectorWidth() const { return RequiredVectorWidth; }
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index e374b16e0e3d..680a52b54385 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -82,6 +82,7 @@ extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeX86Target() {
   initializeX86SpeculativeLoadHardeningPassPass(PR);
   initializeX86FlagsCopyLoweringPassPass(PR);
   initializeX86CondBrFoldingPassPass(PR);
+  initializeX86LoadValueInjectionLoadHardeningPassPass(PR);
   initializeX86LoadValueInjectionRetHardeningPassPass(PR);
   initializeX86OptimizeLEAPassPass(PR);
 }
@@ -497,6 +498,7 @@ void X86PassConfig::addMachineSSAOptimization() {
 
 void X86PassConfig::addPostRegAlloc() {
   addPass(createX86FloatingPointStackifierPass());
+  addPass(createX86LoadValueInjectionLoadHardeningPass());
 }
 
 void X86PassConfig::addPreSched2() { addPass(createX86ExpandPseudoPass()); }
diff --git a/llvm/test/CodeGen/X86/O0-pipeline.ll b/llvm/test/CodeGen/X86/O0-pipeline.ll
index cd1442102d31..a99019941e84 100644
--- a/llvm/test/CodeGen/X86/O0-pipeline.ll
+++ b/llvm/test/CodeGen/X86/O0-pipeline.ll
@@ -55,6 +55,10 @@
 ; CHECK-NEXT:       Fast Register Allocator
 ; CHECK-NEXT:       Bundle Machine CFG Edges
 ; CHECK-NEXT:       X86 FP Stackifier
+; CHECK-NEXT:       MachineDominator Tree Construction
+; CHECK-NEXT:       Machine Natural Loop Construction
+; CHECK-NEXT:       Machine Dominance Frontier Construction
+; CHECK-NEXT:       X86 Load Value Injection (LVI) Load Hardening
 ; CHECK-NEXT:       Lazy Machine Block Frequency Analysis
 ; CHECK-NEXT:       Machine Optimization Remark Emitter
 ; CHECK-NEXT:       Prologue/Epilogue Insertion & Frame Finalization
diff --git a/llvm/test/CodeGen/X86/O3-pipeline.ll b/llvm/test/CodeGen/X86/O3-pipeline.ll
index 1d487bc266de..87ab9ea63b73 100644
--- a/llvm/test/CodeGen/X86/O3-pipeline.ll
+++ b/llvm/test/CodeGen/X86/O3-pipeline.ll
@@ -138,9 +138,11 @@
 ; CHECK-NEXT:       Machine Loop Invariant Code Motion
 ; CHECK-NEXT:       Bundle Machine CFG Edges
 ; CHECK-NEXT:       X86 FP Stackifier
+; CHECK-NEXT:       MachineDominator Tree Construction
+; CHECK-NEXT:       Machine Dominance Frontier Construction
+; CHECK-NEXT:       X86 Load Value Injection (LVI) Load Hardening
 ; CHECK-NEXT:       PostRA Machine Sink
 ; CHECK-NEXT:       Machine Block Frequency Analysis
-; CHECK-NEXT:       MachineDominator Tree Construction
 ; CHECK-NEXT:       MachinePostDominator Tree Construction
 ; CHECK-NEXT:       Lazy Machine Block Frequency Analysis
 ; CHECK-NEXT:       Machine Optimization Remark Emitter
diff --git a/llvm/test/CodeGen/X86/lvi-hardening-gadget-graph.ll b/llvm/test/CodeGen/X86/lvi-hardening-gadget-graph.ll
new file mode 100644
index 000000000000..ba2ce26142b5
--- /dev/null
+++ b/llvm/test/CodeGen/X86/lvi-hardening-gadget-graph.ll
@@ -0,0 +1,129 @@
+; RUN: llc -verify-machineinstrs -mtriple=x86_64-unknown -x86-lvi-load-dot-verify -o %t < %s | FileCheck %s
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @test(i32* %untrusted_user_ptr, i32* %secret, i32 %secret_size) #0 {
+entry:
+  %untrusted_user_ptr.addr = alloca i32*, align 8
+  %secret.addr = alloca i32*, align 8
+  %secret_size.addr = alloca i32, align 4
+  %ret_val = alloca i32, align 4
+  %i = alloca i32, align 4
+  store i32* %untrusted_user_ptr, i32** %untrusted_user_ptr.addr, align 8
+  store i32* %secret, i32** %secret.addr, align 8
+  store i32 %secret_size, i32* %secret_size.addr, align 4
+  store i32 0, i32* %ret_val, align 4
+  call void @llvm.x86.sse2.lfence()
+  store i32 0, i32* %i, align 4
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %0 = load i32, i32* %i, align 4
+  %1 = load i32, i32* %secret_size.addr, align 4
+  %cmp = icmp slt i32 %0, %1
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %2 = load i32, i32* %i, align 4
+  %rem = srem i32 %2, 2
+  %cmp1 = icmp eq i32 %rem, 0
+  br i1 %cmp1, label %if.then, label %if.else
+
+if.then:                                          ; preds = %for.body
+  %3 = load i32*, i32** %secret.addr, align 8
+  %4 = load i32, i32* %ret_val, align 4
+  %idxprom = sext i32 %4 to i64
+  %arrayidx = getelementptr inbounds i32, i32* %3, i64 %idxprom
+  %5 = load i32, i32* %arrayidx, align 4
+  %6 = load i32*, i32** %untrusted_user_ptr.addr, align 8
+  store i32 %5, i32* %6, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %for.body
+  %7 = load i32*, i32** %secret.addr, align 8
+  %8 = load i32, i32* %ret_val, align 4
+  %idxprom2 = sext i32 %8 to i64
+  %arrayidx3 = getelementptr inbounds i32, i32* %7, i64 %idxprom2
+  store i32 42, i32* %arrayidx3, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %9 = load i32*, i32** %untrusted_user_ptr.addr, align 8
+  %10 = load i32, i32* %9, align 4
+  store i32 %10, i32* %ret_val, align 4
+  br label %for.inc
+
+for.inc:                                          ; preds = %if.end
+  %11 = load i32, i32* %i, align 4
+  %inc = add nsw i32 %11, 1
+  store i32 %inc, i32* %i, align 4
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  %12 = load i32, i32* %ret_val, align 4
+  ret i32 %12
+}
+
+; CHECK:      digraph "Speculative gadgets for \"test\" function" {
+; CHECK-NEXT: label="Speculative gadgets for \"test\" function";
+; CHECK:      Node0x{{[0-9a-f]+}} [shape=record,color = green,label="{LFENCE\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 0];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $eax = MOV32rm %stack.4.i, 1, $noreg, 0, $noreg :: (dereferenceable load 4 from %ir.i)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{JCC_1 %bb.6, 13, implicit killed $eflags\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{CMP32rm killed renamable $eax, %stack.2.secret_size.addr, 1, $noreg, 0, $noreg, implicit-def $eflags :: (dereferenceable load 4 from %ir.secret_size.addr)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $eax = MOV32rm %stack.4.i, 1, $noreg, 0, $noreg :: (dereferenceable load 4 from %ir.i)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{JCC_1 %bb.4, 5, implicit killed $eflags\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $rax = MOV64rm %stack.1.secret.addr, 1, $noreg, 0, $noreg :: (dereferenceable load 8 from %ir.secret.addr)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $eax = MOV32rm killed renamable $rax, 4, killed renamable $rcx, 0, $noreg :: (load 4 from %ir.arrayidx)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $rcx = MOVSX64rm32 %stack.3.ret_val, 1, $noreg, 0, $noreg :: (dereferenceable load 4 from %ir.ret_val)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $rcx = MOV64rm %stack.0.untrusted_user_ptr.addr, 1, $noreg, 0, $noreg :: (dereferenceable load 8 from %ir.untrusted_user_ptr.addr)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{MOV32mr killed renamable $rcx, 1, $noreg, 0, $noreg, killed renamable $eax :: (store 4 into %ir.6)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $rax = MOV64rm %stack.1.secret.addr, 1, $noreg, 0, $noreg :: (dereferenceable load 8 from %ir.secret.addr)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{MOV32mi killed renamable $rax, 4, killed renamable $rcx, 0, $noreg, 42 :: (store 4 into %ir.arrayidx3)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $rcx = MOVSX64rm32 %stack.3.ret_val, 1, $noreg, 0, $noreg :: (dereferenceable load 4 from %ir.ret_val)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $rax = MOV64rm %stack.0.untrusted_user_ptr.addr, 1, $noreg, 0, $noreg :: (dereferenceable load 8 from %ir.untrusted_user_ptr.addr)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[color = red, style = "dashed"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $eax = MOV32rm killed renamable $rax, 1, $noreg, 0, $noreg :: (load 4 from %ir.9)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,color = blue,label="{ARGS}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 0];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{MOV64mr %stack.0.untrusted_user_ptr.addr, 1, $noreg, 0, $noreg, killed renamable $rdi :: (store 8 into %ir.untrusted_user_ptr.addr)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 0];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{JMP_1 %bb.5\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{JMP_1 %bb.1\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 1];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{renamable $eax = MOV32rm %stack.3.ret_val, 1, $noreg, 0, $noreg :: (dereferenceable load 4 from %ir.ret_val)\n}"];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} -> Node0x{{[0-9a-f]+}}[label = 0];
+; CHECK-NEXT: Node0x{{[0-9a-f]+}} [shape=record,label="{RET 0, $eax\n}"];
+; CHECK-NEXT: }
+
+; Function Attrs: nounwind
+declare void @llvm.x86.sse2.lfence() #1
+
+attributes #0 = { "target-features"="+lvi-cfi"
+                  "target-features"="+lvi-load-hardening" }
+attributes #1 = { nounwind }