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Current view: top level - include/llvm/Transforms/Utils - SymbolRewriter.h (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 3 6 50.0 %
Date: 2017-09-14 15:23:50 Functions: 0 1 0.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===-- SymbolRewriter.h - Symbol Rewriting Pass ----------------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // This file provides the prototypes and definitions related to the Symbol
      11             : // Rewriter pass.
      12             : //
      13             : // The Symbol Rewriter pass takes a set of rewrite descriptors which define
      14             : // transformations for symbol names.  These can be either single name to name
      15             : // trnsformation or more broad regular expression based transformations.
      16             : //
      17             : // All the functions are re-written at the IR level.  The Symbol Rewriter itself
      18             : // is exposed as a module level pass.  All symbols at the module level are
      19             : // iterated.  For any matching symbol, the requested transformation is applied,
      20             : // updating references to it as well (a la RAUW).  The resulting binary will
      21             : // only contain the rewritten symbols.
      22             : //
      23             : // By performing this operation in the compiler, we are able to catch symbols
      24             : // that would otherwise not be possible to catch (e.g. inlined symbols).
      25             : //
      26             : // This makes it possible to cleanly transform symbols without resorting to
      27             : // overly-complex macro tricks and the pre-processor.  An example of where this
      28             : // is useful is the sanitizers where we would like to intercept a well-defined
      29             : // set of functions across the module.
      30             : //
      31             : //===----------------------------------------------------------------------===//
      32             : 
      33             : #ifndef LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
      34             : #define LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
      35             : 
      36             : #include "llvm/IR/Module.h"
      37             : #include "llvm/IR/PassManager.h"
      38             : #include <list>
      39             : #include <memory>
      40             : #include <string>
      41             : 
      42             : namespace llvm {
      43             : 
      44             : class MemoryBuffer;
      45             : 
      46             : namespace yaml {
      47             : 
      48             : class KeyValueNode;
      49             : class MappingNode;
      50             : class ScalarNode;
      51             : class Stream;
      52             : 
      53             : } // end namespace yaml
      54             : 
      55             : namespace SymbolRewriter {
      56             : 
      57             : /// The basic entity representing a rewrite operation.  It serves as the base
      58             : /// class for any rewrite descriptor.  It has a certain set of specializations
      59             : /// which describe a particular rewrite.
      60             : ///
      61             : /// The RewriteMapParser can be used to parse a mapping file that provides the
      62             : /// mapping for rewriting the symbols.  The descriptors individually describe
      63             : /// whether to rewrite a function, global variable, or global alias.  Each of
      64             : /// these can be selected either by explicitly providing a name for the ones to
      65             : /// be rewritten or providing a (posix compatible) regular expression that will
      66             : /// select the symbols to rewrite.  This descriptor list is passed to the
      67             : /// SymbolRewriter pass.
      68             : class RewriteDescriptor {
      69             : public:
      70             :   enum class Type {
      71             :     Invalid,        /// invalid
      72             :     Function,       /// function - descriptor rewrites a function
      73             :     GlobalVariable, /// global variable - descriptor rewrites a global variable
      74             :     NamedAlias,     /// named alias - descriptor rewrites a global alias
      75             :   };
      76             : 
      77             :   RewriteDescriptor(const RewriteDescriptor &) = delete;
      78             :   RewriteDescriptor &operator=(const RewriteDescriptor &) = delete;
      79             :   virtual ~RewriteDescriptor() = default;
      80             : 
      81             :   Type getType() const { return Kind; }
      82             : 
      83             :   virtual bool performOnModule(Module &M) = 0;
      84             : 
      85             : protected:
      86          26 :   explicit RewriteDescriptor(Type T) : Kind(T) {}
      87             : 
      88             : private:
      89             :   const Type Kind;
      90             : };
      91             : 
      92             : typedef std::list<std::unique_ptr<RewriteDescriptor>> RewriteDescriptorList;
      93             : 
      94             : class RewriteMapParser {
      95             : public:
      96             :   bool parse(const std::string &MapFile, RewriteDescriptorList *Descriptors);
      97             : 
      98             : private:
      99             :   bool parse(std::unique_ptr<MemoryBuffer> &MapFile, RewriteDescriptorList *DL);
     100             :   bool parseEntry(yaml::Stream &Stream, yaml::KeyValueNode &Entry,
     101             :                   RewriteDescriptorList *DL);
     102             :   bool parseRewriteFunctionDescriptor(yaml::Stream &Stream,
     103             :                                       yaml::ScalarNode *Key,
     104             :                                       yaml::MappingNode *Value,
     105             :                                       RewriteDescriptorList *DL);
     106             :   bool parseRewriteGlobalVariableDescriptor(yaml::Stream &Stream,
     107             :                                             yaml::ScalarNode *Key,
     108             :                                             yaml::MappingNode *Value,
     109             :                                             RewriteDescriptorList *DL);
     110             :   bool parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
     111             :                                          yaml::MappingNode *V,
     112             :                                          RewriteDescriptorList *DL);
     113             : };
     114             : 
     115             : } // end namespace SymbolRewriter
     116             : 
     117             : ModulePass *createRewriteSymbolsPass();
     118             : ModulePass *createRewriteSymbolsPass(SymbolRewriter::RewriteDescriptorList &);
     119             : 
     120       33652 : class RewriteSymbolPass : public PassInfoMixin<RewriteSymbolPass> {
     121             : public:
     122       33850 :   RewriteSymbolPass() { loadAndParseMapFiles(); }
     123           0 :   RewriteSymbolPass(SymbolRewriter::RewriteDescriptorList &DL) {
     124           0 :     Descriptors.splice(Descriptors.begin(), DL);
     125           0 :   }
     126             : 
     127             :   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
     128             : 
     129             :   // Glue for old PM
     130             :   bool runImpl(Module &M);
     131             : 
     132             : private:
     133             :   void loadAndParseMapFiles();
     134             : 
     135             :   SymbolRewriter::RewriteDescriptorList Descriptors;  
     136             : };
     137             : 
     138             : } // end namespace llvm
     139             : 
     140             : #endif //LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H

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