/Users/buildslave/jenkins/sharedspace/clang-stage2-coverage-R@2/llvm/include/llvm/Transforms/IPO/Internalize.h
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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 | 247 | : 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 | 245 | CallGraph *CG = nullptr) { |
74 | 245 | return InternalizePass(std::move(MustPreserveGV)) |
75 | 245 | .internalizeModule(TheModule, CG); |
76 | 245 | } |
77 | | } // end namespace llvm |
78 | | |
79 | | #endif // LLVM_TRANSFORMS_IPO_INTERNALIZE_H |