Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Transforms/Utils/SymbolRewriter.h
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//===- SymbolRewriter.h - Symbol Rewriting Pass -----------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file provides the prototypes and definitions related to the Symbol
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// Rewriter pass.
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//
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// The Symbol Rewriter pass takes a set of rewrite descriptors which define
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// transformations for symbol names.  These can be either single name to name
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// trnsformation or more broad regular expression based transformations.
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//
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// All the functions are re-written at the IR level.  The Symbol Rewriter itself
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// is exposed as a module level pass.  All symbols at the module level are
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// iterated.  For any matching symbol, the requested transformation is applied,
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// updating references to it as well (a la RAUW).  The resulting binary will
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// only contain the rewritten symbols.
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//
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// By performing this operation in the compiler, we are able to catch symbols
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// that would otherwise not be possible to catch (e.g. inlined symbols).
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//
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// This makes it possible to cleanly transform symbols without resorting to
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// overly-complex macro tricks and the pre-processor.  An example of where this
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// is useful is the sanitizers where we would like to intercept a well-defined
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// set of functions across the module.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
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#define LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
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#include "llvm/IR/PassManager.h"
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#include <list>
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#include <memory>
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#include <string>
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namespace llvm {
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class MemoryBuffer;
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class Module;
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class ModulePass;
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namespace yaml {
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class KeyValueNode;
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class MappingNode;
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class ScalarNode;
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class Stream;
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} // end namespace yaml
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namespace SymbolRewriter {
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/// The basic entity representing a rewrite operation.  It serves as the base
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/// class for any rewrite descriptor.  It has a certain set of specializations
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/// which describe a particular rewrite.
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///
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/// The RewriteMapParser can be used to parse a mapping file that provides the
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/// mapping for rewriting the symbols.  The descriptors individually describe
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/// whether to rewrite a function, global variable, or global alias.  Each of
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/// these can be selected either by explicitly providing a name for the ones to
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/// be rewritten or providing a (posix compatible) regular expression that will
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/// select the symbols to rewrite.  This descriptor list is passed to the
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/// SymbolRewriter pass.
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class RewriteDescriptor {
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public:
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  enum class Type {
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    Invalid,        /// invalid
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    Function,       /// function - descriptor rewrites a function
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    GlobalVariable, /// global variable - descriptor rewrites a global variable
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    NamedAlias,     /// named alias - descriptor rewrites a global alias
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  };
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  RewriteDescriptor(const RewriteDescriptor &) = delete;
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  RewriteDescriptor &operator=(const RewriteDescriptor &) = delete;
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  virtual ~RewriteDescriptor() = default;
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  Type getType() const { return Kind; }
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  virtual bool performOnModule(Module &M) = 0;
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protected:
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  explicit RewriteDescriptor(Type T) : Kind(T) {}
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private:
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  const Type Kind;
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};
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using RewriteDescriptorList = std::list<std::unique_ptr<RewriteDescriptor>>;
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class RewriteMapParser {
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public:
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  bool parse(const std::string &MapFile, RewriteDescriptorList *Descriptors);
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private:
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  bool parse(std::unique_ptr<MemoryBuffer> &MapFile, RewriteDescriptorList *DL);
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  bool parseEntry(yaml::Stream &Stream, yaml::KeyValueNode &Entry,
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                  RewriteDescriptorList *DL);
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  bool parseRewriteFunctionDescriptor(yaml::Stream &Stream,
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                                      yaml::ScalarNode *Key,
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                                      yaml::MappingNode *Value,
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                                      RewriteDescriptorList *DL);
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  bool parseRewriteGlobalVariableDescriptor(yaml::Stream &Stream,
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                                            yaml::ScalarNode *Key,
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                                            yaml::MappingNode *Value,
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                                            RewriteDescriptorList *DL);
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  bool parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
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                                         yaml::MappingNode *V,
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                                         RewriteDescriptorList *DL);
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};
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} // end namespace SymbolRewriter
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ModulePass *createRewriteSymbolsPass();
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ModulePass *createRewriteSymbolsPass(SymbolRewriter::RewriteDescriptorList &);
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class RewriteSymbolPass : public PassInfoMixin<RewriteSymbolPass> {
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public:
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  RewriteSymbolPass() { loadAndParseMapFiles(); }
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  RewriteSymbolPass(SymbolRewriter::RewriteDescriptorList &DL) {
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    Descriptors.splice(Descriptors.begin(), DL);
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  }
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  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
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  // Glue for old PM
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  bool runImpl(Module &M);
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private:
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  void loadAndParseMapFiles();
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  SymbolRewriter::RewriteDescriptorList Descriptors;
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};
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} // end namespace llvm
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#endif //LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H