[InstCombine] Signed saturation patterns
[llvm-core.git] / include / llvm / Transforms / Utils / SymbolRewriter.h
blobce9dcaf2b74f92b91a523c9e9d69c2c654597c4f
1 //===- SymbolRewriter.h - Symbol Rewriting Pass -----------------*- 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 provides the prototypes and definitions related to the Symbol
10 // Rewriter pass.
12 // The Symbol Rewriter pass takes a set of rewrite descriptors which define
13 // transformations for symbol names. These can be either single name to name
14 // trnsformation or more broad regular expression based transformations.
16 // All the functions are re-written at the IR level. The Symbol Rewriter itself
17 // is exposed as a module level pass. All symbols at the module level are
18 // iterated. For any matching symbol, the requested transformation is applied,
19 // updating references to it as well (a la RAUW). The resulting binary will
20 // only contain the rewritten symbols.
22 // By performing this operation in the compiler, we are able to catch symbols
23 // that would otherwise not be possible to catch (e.g. inlined symbols).
25 // This makes it possible to cleanly transform symbols without resorting to
26 // overly-complex macro tricks and the pre-processor. An example of where this
27 // is useful is the sanitizers where we would like to intercept a well-defined
28 // set of functions across the module.
30 //===----------------------------------------------------------------------===//
32 #ifndef LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
33 #define LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
35 #include "llvm/IR/PassManager.h"
36 #include <list>
37 #include <memory>
38 #include <string>
40 namespace llvm {
42 class MemoryBuffer;
43 class Module;
44 class ModulePass;
46 namespace yaml {
48 class KeyValueNode;
49 class MappingNode;
50 class ScalarNode;
51 class Stream;
53 } // end namespace yaml
55 namespace SymbolRewriter {
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
77 RewriteDescriptor(const RewriteDescriptor &) = delete;
78 RewriteDescriptor &operator=(const RewriteDescriptor &) = delete;
79 virtual ~RewriteDescriptor() = default;
81 Type getType() const { return Kind; }
83 virtual bool performOnModule(Module &M) = 0;
85 protected:
86 explicit RewriteDescriptor(Type T) : Kind(T) {}
88 private:
89 const Type Kind;
92 using RewriteDescriptorList = std::list<std::unique_ptr<RewriteDescriptor>>;
94 class RewriteMapParser {
95 public:
96 bool parse(const std::string &MapFile, RewriteDescriptorList *Descriptors);
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);
115 } // end namespace SymbolRewriter
117 ModulePass *createRewriteSymbolsPass();
118 ModulePass *createRewriteSymbolsPass(SymbolRewriter::RewriteDescriptorList &);
120 class RewriteSymbolPass : public PassInfoMixin<RewriteSymbolPass> {
121 public:
122 RewriteSymbolPass() { loadAndParseMapFiles(); }
124 RewriteSymbolPass(SymbolRewriter::RewriteDescriptorList &DL) {
125 Descriptors.splice(Descriptors.begin(), DL);
128 PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
130 // Glue for old PM
131 bool runImpl(Module &M);
133 private:
134 void loadAndParseMapFiles();
136 SymbolRewriter::RewriteDescriptorList Descriptors;
139 } // end namespace llvm
141 #endif //LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H