1 | //====- Internalize.h - Internalization API ---------------------*- C++ -*-===// |
2 | // |
3 | // The LLVM Compiler Infrastructure |
4 | // |
5 | // This file is distributed under the University of Illinois Open Source |
6 | // License. See LICENSE.TXT for details. |
7 | // |
8 | //===----------------------------------------------------------------------===// |
9 | // |
10 | // This pass loops over all of the functions and variables in the input module. |
11 | // If the function or variable does not need to be preserved according to the |
12 | // client supplied callback, it is marked as internal. |
13 | // |
14 | // This transformation would not be legal in a regular compilation, but it gets |
15 | // extra information from the linker about what is safe. |
16 | // |
17 | // For example: Internalizing a function with external linkage. Only if we are |
18 | // told it is only used from within this module, it is safe to do it. |
19 | // |
20 | //===----------------------------------------------------------------------===// |
21 | |
22 | #ifndef LLVM_TRANSFORMS_IPO_INTERNALIZE_H |
23 | #define LLVM_TRANSFORMS_IPO_INTERNALIZE_H |
24 | |
25 | #include "llvm/ADT/StringSet.h" |
26 | #include "llvm/IR/GlobalValue.h" |
27 | #include "llvm/IR/PassManager.h" |
28 | #include <functional> |
29 | #include <set> |
30 | |
31 | namespace llvm { |
32 | class Module; |
33 | class CallGraph; |
34 | |
35 | /// A pass that internalizes all functions and variables other than those that |
36 | /// must be preserved according to \c MustPreserveGV. |
37 | class InternalizePass : public PassInfoMixin<InternalizePass> { |
38 | /// Client supplied callback to control wheter a symbol must be preserved. |
39 | const std::function<bool(const GlobalValue &)> MustPreserveGV; |
40 | /// Set of symbols private to the compiler that this pass should not touch. |
41 | StringSet<> AlwaysPreserved; |
42 | |
43 | /// Return false if we're allowed to internalize this GV. |
44 | bool shouldPreserveGV(const GlobalValue &GV); |
45 | /// Internalize GV if it is possible to do so, i.e. it is not externally |
46 | /// visible and is not a member of an externally visible comdat. |
47 | bool maybeInternalize(GlobalValue &GV, |
48 | const std::set<const Comdat *> &ExternalComdats); |
49 | /// If GV is part of a comdat and is externally visible, keep track of its |
50 | /// comdat so that we don't internalize any of its members. |
51 | void checkComdatVisibility(GlobalValue &GV, |
52 | std::set<const Comdat *> &ExternalComdats); |
53 | |
54 | public: |
55 | InternalizePass(); |
56 | InternalizePass(std::function<bool(const GlobalValue &)> MustPreserveGV) |
57 | : MustPreserveGV(std::move(MustPreserveGV)) {} |
58 | |
59 | /// Run the internalizer on \p TheModule, returns true if any changes was |
60 | /// made. |
61 | /// |
62 | /// If the CallGraph \p CG is supplied, it will be updated when |
63 | /// internalizing a function (by removing any edge from the "external node") |
64 | bool internalizeModule(Module &TheModule, CallGraph *CG = nullptr); |
65 | |
66 | PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM); |
67 | }; |
68 | |
69 | /// Helper function to internalize functions and variables in a Module. |
70 | inline bool |
71 | internalizeModule(Module &TheModule, |
72 | std::function<bool(const GlobalValue &)> MustPreserveGV, |
73 | CallGraph *CG = nullptr) { |
74 | return InternalizePass(std::move(MustPreserveGV)) |
75 | .internalizeModule(TheModule, CG); |
76 | } |
77 | } // end namespace llvm |
78 | |
79 | #endif // LLVM_TRANSFORMS_IPO_INTERNALIZE_H |
80 | |