LLVM 19.0.0git
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;
44
45namespace yaml {
46
47class KeyValueNode;
48class MappingNode;
49class ScalarNode;
50class Stream;
51
52} // end namespace yaml
53
54namespace SymbolRewriter {
55
56/// The basic entity representing a rewrite operation. It serves as the base
57/// class for any rewrite descriptor. It has a certain set of specializations
58/// which describe a particular rewrite.
59///
60/// The RewriteMapParser can be used to parse a mapping file that provides the
61/// mapping for rewriting the symbols. The descriptors individually describe
62/// whether to rewrite a function, global variable, or global alias. Each of
63/// these can be selected either by explicitly providing a name for the ones to
64/// be rewritten or providing a (posix compatible) regular expression that will
65/// select the symbols to rewrite. This descriptor list is passed to the
66/// SymbolRewriter pass.
68public:
69 enum class Type {
70 Invalid, /// invalid
71 Function, /// function - descriptor rewrites a function
72 GlobalVariable, /// global variable - descriptor rewrites a global variable
73 NamedAlias, /// named alias - descriptor rewrites a global alias
74 };
75
78 virtual ~RewriteDescriptor() = default;
79
80 Type getType() const { return Kind; }
81
82 virtual bool performOnModule(Module &M) = 0;
83
84protected:
85 explicit RewriteDescriptor(Type T) : Kind(T) {}
86
87private:
88 const Type Kind;
89};
90
91using RewriteDescriptorList = std::list<std::unique_ptr<RewriteDescriptor>>;
92
94public:
95 bool parse(const std::string &MapFile, RewriteDescriptorList *Descriptors);
96
97private:
98 bool parse(std::unique_ptr<MemoryBuffer> &MapFile, RewriteDescriptorList *DL);
99 bool parseEntry(yaml::Stream &Stream, yaml::KeyValueNode &Entry,
101 bool parseRewriteFunctionDescriptor(yaml::Stream &Stream,
102 yaml::ScalarNode *Key,
105 bool parseRewriteGlobalVariableDescriptor(yaml::Stream &Stream,
106 yaml::ScalarNode *Key,
109 bool parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
112};
113
114} // end namespace SymbolRewriter
115
116class RewriteSymbolPass : public PassInfoMixin<RewriteSymbolPass> {
117public:
118 RewriteSymbolPass() { loadAndParseMapFiles(); }
119
121 Descriptors.splice(Descriptors.begin(), DL);
122 }
123
125
126 // Glue for old PM
127 bool runImpl(Module &M);
128
129private:
130 void loadAndParseMapFiles();
131
133};
134
135} // end namespace llvm
136
137#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:348
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: Analysis.h:109
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:290
Represents a YAML map created from either a block map for a flow map.
Definition: YAMLParser.h:419
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
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:91
Definition: regcomp.c:192