1 //===- SymbolRewriter.h - Symbol Rewriting Pass -----------------*- C++ -*-===//
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
7 //===----------------------------------------------------------------------===//
9 // This file provides the prototypes and definitions related to the Symbol
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"
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.
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
{
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;
86 explicit RewriteDescriptor(Type T
) : Kind(T
) {}
92 using RewriteDescriptorList
= std::list
<std::unique_ptr
<RewriteDescriptor
>>;
94 class RewriteMapParser
{
96 bool parse(const std::string
&MapFile
, RewriteDescriptorList
*Descriptors
);
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
> {
122 RewriteSymbolPass() { loadAndParseMapFiles(); }
124 RewriteSymbolPass(SymbolRewriter::RewriteDescriptorList
&DL
) {
125 Descriptors
.splice(Descriptors
.begin(), DL
);
128 PreservedAnalyses
run(Module
&M
, ModuleAnalysisManager
&AM
);
131 bool runImpl(Module
&M
);
134 void loadAndParseMapFiles();
136 SymbolRewriter::RewriteDescriptorList Descriptors
;
139 } // end namespace llvm
141 #endif //LLVM_TRANSFORMS_UTILS_SYMBOLREWRITER_H