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      1 //===- Verifier.h - LLVM IR Verifier ----------------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // This file defines the function verifier interface, that can be used for some
     10 // sanity checking of input to the system, and for checking that transformations
     11 // haven't done something bad.
     12 //
     13 // Note that this does not provide full 'java style' security and verifications,
     14 // instead it just tries to ensure that code is well formed.
     15 //
     16 // To see what specifically is checked, look at the top of Verifier.cpp
     17 //
     18 //===----------------------------------------------------------------------===//
     19 
     20 #ifndef LLVM_IR_VERIFIER_H
     21 #define LLVM_IR_VERIFIER_H
     22 
     23 #include "llvm/ADT/DenseMap.h"
     24 #include "llvm/IR/PassManager.h"
     25 #include <utility>
     26 
     27 namespace llvm {
     28 
     29 class APInt;
     30 class Function;
     31 class FunctionPass;
     32 class Instruction;
     33 class MDNode;
     34 class Module;
     35 class raw_ostream;
     36 struct VerifierSupport;
     37 
     38 /// Verify that the TBAA Metadatas are valid.
     39 class TBAAVerifier {
     40   VerifierSupport *Diagnostic = nullptr;
     41 
     42   /// Helper to diagnose a failure
     43   template <typename... Tys> void CheckFailed(Tys &&... Args);
     44 
     45   /// Cache of TBAA base nodes that have already been visited.  This cachce maps
     46   /// a node that has been visited to a pair (IsInvalid, BitWidth) where
     47   ///
     48   ///  \c IsInvalid is true iff the node is invalid.
     49   ///  \c BitWidth, if non-zero, is the bitwidth of the integer used to denoting
     50   ///    the offset of the access.  If zero, only a zero offset is allowed.
     51   ///
     52   /// \c BitWidth has no meaning if \c IsInvalid is true.
     53   using TBAABaseNodeSummary = std::pair<bool, unsigned>;
     54   DenseMap<const MDNode *, TBAABaseNodeSummary> TBAABaseNodes;
     55 
     56   /// Maps an alleged scalar TBAA node to a boolean that is true if the said
     57   /// TBAA node is a valid scalar TBAA node or false otherwise.
     58   DenseMap<const MDNode *, bool> TBAAScalarNodes;
     59 
     60   /// \name Helper functions used by \c visitTBAAMetadata.
     61   /// @{
     62   MDNode *getFieldNodeFromTBAABaseNode(Instruction &I, const MDNode *BaseNode,
     63                                        APInt &Offset, bool IsNewFormat);
     64   TBAAVerifier::TBAABaseNodeSummary verifyTBAABaseNode(Instruction &I,
     65                                                        const MDNode *BaseNode,
     66                                                        bool IsNewFormat);
     67   TBAABaseNodeSummary verifyTBAABaseNodeImpl(Instruction &I,
     68                                              const MDNode *BaseNode,
     69                                              bool IsNewFormat);
     70 
     71   bool isValidScalarTBAANode(const MDNode *MD);
     72   /// @}
     73 
     74 public:
     75   TBAAVerifier(VerifierSupport *Diagnostic = nullptr)
     76       : Diagnostic(Diagnostic) {}
     77   /// Visit an instruction and return true if it is valid, return false if an
     78   /// invalid TBAA is attached.
     79   bool visitTBAAMetadata(Instruction &I, const MDNode *MD);
     80 };
     81 
     82 /// Check a function for errors, useful for use when debugging a
     83 /// pass.
     84 ///
     85 /// If there are no errors, the function returns false. If an error is found,
     86 /// a message describing the error is written to OS (if non-null) and true is
     87 /// returned.
     88 bool verifyFunction(const Function &F, raw_ostream *OS = nullptr);
     89 
     90 /// Check a module for errors.
     91 ///
     92 /// If there are no errors, the function returns false. If an error is
     93 /// found, a message describing the error is written to OS (if
     94 /// non-null) and true is returned.
     95 ///
     96 /// \return true if the module is broken. If BrokenDebugInfo is
     97 /// supplied, DebugInfo verification failures won't be considered as
     98 /// error and instead *BrokenDebugInfo will be set to true. Debug
     99 /// info errors can be "recovered" from by stripping the debug info.
    100 bool verifyModule(const Module &M, raw_ostream *OS = nullptr,
    101                   bool *BrokenDebugInfo = nullptr);
    102 
    103 FunctionPass *createVerifierPass(bool FatalErrors = true);
    104 
    105 /// Check a module for errors, and report separate error states for IR
    106 /// and debug info errors.
    107 class VerifierAnalysis : public AnalysisInfoMixin<VerifierAnalysis> {
    108   friend AnalysisInfoMixin<VerifierAnalysis>;
    109 
    110   static AnalysisKey Key;
    111 
    112 public:
    113   struct Result {
    114     bool IRBroken, DebugInfoBroken;
    115   };
    116 
    117   Result run(Module &M, ModuleAnalysisManager &);
    118   Result run(Function &F, FunctionAnalysisManager &);
    119   static bool isRequired() { return true; }
    120 };
    121 
    122 /// Check a module for errors, but report debug info errors separately.
    123 /// Otherwise behaves as the normal verifyModule. Debug info errors can be
    124 /// "recovered" from by stripping the debug info.
    125 bool verifyModule(bool &BrokenDebugInfo, const Module &M, raw_ostream *OS);
    126 
    127 /// Create a verifier pass.
    128 ///
    129 /// Check a module or function for validity. This is essentially a pass wrapped
    130 /// around the above verifyFunction and verifyModule routines and
    131 /// functionality. When the pass detects a verification error it is always
    132 /// printed to stderr, and by default they are fatal. You can override that by
    133 /// passing \c false to \p FatalErrors.
    134 ///
    135 /// Note that this creates a pass suitable for the legacy pass manager. It has
    136 /// nothing to do with \c VerifierPass.
    137 class VerifierPass : public PassInfoMixin<VerifierPass> {
    138   bool FatalErrors;
    139 
    140 public:
    141   explicit VerifierPass(bool FatalErrors = true) : FatalErrors(FatalErrors) {}
    142 
    143   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
    144   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
    145   static bool isRequired() { return true; }
    146 };
    147 
    148 } // end namespace llvm
    149 
    150 #endif // LLVM_IR_VERIFIER_H
    151