LLVM 17.0.0git
SymbolRewriter.h
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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.
11//
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.
15//
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.
21//
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).
24//
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.
29//
30//===----------------------------------------------------------------------===//
31
32#ifndef LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
33#define LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
34
35#include "llvm/IR/PassManager.h"
36#include <list>
37#include <memory>
38#include <string>
39
40namespace llvm {
41
42class MemoryBuffer;
43class Module;
44class ModulePass;
45
46namespace yaml {
47
48class KeyValueNode;
49class MappingNode;
50class ScalarNode;
51class Stream;
52
53} // end namespace yaml
54
55namespace 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.
69public:
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
79 virtual ~RewriteDescriptor() = default;
80
81 Type getType() const { return Kind; }
82
83 virtual bool performOnModule(Module &M) = 0;
84
85protected:
86 explicit RewriteDescriptor(Type T) : Kind(T) {}
87
88private:
89 const Type Kind;
90};
91
92using RewriteDescriptorList = std::list<std::unique_ptr<RewriteDescriptor>>;
93
95public:
96 bool parse(const std::string &MapFile, RewriteDescriptorList *Descriptors);
97
98private:
99 bool parse(std::unique_ptr<MemoryBuffer> &MapFile, RewriteDescriptorList *DL);
100 bool parseEntry(yaml::Stream &Stream, yaml::KeyValueNode &Entry,
102 bool parseRewriteFunctionDescriptor(yaml::Stream &Stream,
103 yaml::ScalarNode *Key,
106 bool parseRewriteGlobalVariableDescriptor(yaml::Stream &Stream,
107 yaml::ScalarNode *Key,
110 bool parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
113};
114
115} // end namespace SymbolRewriter
116
119
120class RewriteSymbolPass : public PassInfoMixin<RewriteSymbolPass> {
121public:
122 RewriteSymbolPass() { loadAndParseMapFiles(); }
123
125 Descriptors.splice(Descriptors.begin(), DL);
126 }
127
129
130 // Glue for old PM
131 bool runImpl(Module &M);
132
133private:
134 void loadAndParseMapFiles();
135
137};
138
139} // end namespace llvm
140
141#endif // LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
Machine Check Debug Module
This header defines various interfaces for pass management in LLVM.
A container for analyses that lazily runs them and caches their results.
Definition: PassManager.h:620
ModulePass class - This class is used to implement unstructured interprocedural optimizations and ana...
Definition: Pass.h:251
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:152
PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM)
RewriteSymbolPass(SymbolRewriter::RewriteDescriptorList &DL)
The basic entity representing a rewrite operation.
RewriteDescriptor(const RewriteDescriptor &)=delete
@ GlobalVariable
function - descriptor rewrites a function
@ NamedAlias
global variable - descriptor rewrites a global variable
RewriteDescriptor & operator=(const RewriteDescriptor &)=delete
virtual bool performOnModule(Module &M)=0
The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
LLVM Value Representation.
Definition: Value.h:74
A key and value pair.
Definition: YAMLParser.h:285
Represents a YAML map created from either a block map for a flow map.
Definition: YAMLParser.h:414
A scalar node is an opaque datum that can be presented as a series of zero or more Unicode scalar val...
Definition: YAMLParser.h:212
This class represents a YAML stream potentially containing multiple documents.
Definition: YAMLParser.h:86
std::list< std::unique_ptr< RewriteDescriptor > > RewriteDescriptorList
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
ModulePass * createRewriteSymbolsPass()
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:371
Definition: regcomp.c:192