/Users/buildslave/jenkins/sharedspace/clang-stage2-coverage-R@2/llvm/include/llvm/Transforms/Utils/FunctionImportUtils.h
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1 | | //===- FunctionImportUtils.h - Importing support utilities -----*- 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 file defines the FunctionImportGlobalProcessing class which is used |
11 | | // to perform the necessary global value handling for function importing. |
12 | | // |
13 | | //===----------------------------------------------------------------------===// |
14 | | |
15 | | #ifndef LLVM_TRANSFORMS_UTILS_FUNCTIONIMPORTUTILS_H |
16 | | #define LLVM_TRANSFORMS_UTILS_FUNCTIONIMPORTUTILS_H |
17 | | |
18 | | #include "llvm/ADT/SetVector.h" |
19 | | #include "llvm/IR/ModuleSummaryIndex.h" |
20 | | |
21 | | namespace llvm { |
22 | | class Module; |
23 | | |
24 | | /// Class to handle necessary GlobalValue changes required by ThinLTO |
25 | | /// function importing, including linkage changes and any necessary renaming. |
26 | | class FunctionImportGlobalProcessing { |
27 | | /// The Module which we are exporting or importing functions from. |
28 | | Module &M; |
29 | | |
30 | | /// Module summary index passed in for function importing/exporting handling. |
31 | | const ModuleSummaryIndex &ImportIndex; |
32 | | |
33 | | /// Globals to import from this module, all other functions will be |
34 | | /// imported as declarations instead of definitions. |
35 | | SetVector<GlobalValue *> *GlobalsToImport; |
36 | | |
37 | | /// Set to true if the given ModuleSummaryIndex contains any functions |
38 | | /// from this source module, in which case we must conservatively assume |
39 | | /// that any of its functions may be imported into another module |
40 | | /// as part of a different backend compilation process. |
41 | | bool HasExportedFunctions = false; |
42 | | |
43 | | /// Set of llvm.*used values, in order to validate that we don't try |
44 | | /// to promote any non-renamable values. |
45 | | SmallPtrSet<GlobalValue *, 8> Used; |
46 | | |
47 | | /// Check if we should promote the given local value to global scope. |
48 | | bool shouldPromoteLocalToGlobal(const GlobalValue *SGV); |
49 | | |
50 | | #ifndef NDEBUG |
51 | | /// Check if the given value is a local that can't be renamed (promoted). |
52 | | /// Only used in assertion checking, and disabled under NDEBUG since the Used |
53 | | /// set will not be populated. |
54 | | bool isNonRenamableLocal(const GlobalValue &GV) const; |
55 | | #endif |
56 | | |
57 | | /// Helper methods to check if we are importing from or potentially |
58 | | /// exporting from the current source module. |
59 | 1.43k | bool isPerformingImport() const { return GlobalsToImport != nullptr; } |
60 | 1.48k | bool isModuleExporting() const { return HasExportedFunctions; } |
61 | | |
62 | | /// If we are importing from the source module, checks if we should |
63 | | /// import SGV as a definition, otherwise import as a declaration. |
64 | | bool doImportAsDefinition(const GlobalValue *SGV); |
65 | | |
66 | | /// Get the name for SGV that should be used in the linked destination |
67 | | /// module. Specifically, this handles the case where we need to rename |
68 | | /// a local that is being promoted to global scope, which it will always |
69 | | /// do when \p DoPromote is true (or when importing a local). |
70 | | std::string getName(const GlobalValue *SGV, bool DoPromote); |
71 | | |
72 | | /// Process globals so that they can be used in ThinLTO. This includes |
73 | | /// promoting local variables so that they can be reference externally by |
74 | | /// thin lto imported globals and converting strong external globals to |
75 | | /// available_externally. |
76 | | void processGlobalsForThinLTO(); |
77 | | void processGlobalForThinLTO(GlobalValue &GV); |
78 | | |
79 | | /// Get the new linkage for SGV that should be used in the linked destination |
80 | | /// module. Specifically, for ThinLTO importing or exporting it may need |
81 | | /// to be adjusted. When \p DoPromote is true then we must adjust the |
82 | | /// linkage for a required promotion of a local to global scope. |
83 | | GlobalValue::LinkageTypes getLinkage(const GlobalValue *SGV, bool DoPromote); |
84 | | |
85 | | public: |
86 | | FunctionImportGlobalProcessing( |
87 | | Module &M, const ModuleSummaryIndex &Index, |
88 | | SetVector<GlobalValue *> *GlobalsToImport = nullptr) |
89 | 319 | : M(M), ImportIndex(Index), GlobalsToImport(GlobalsToImport) { |
90 | 319 | // If we have a ModuleSummaryIndex but no function to import, |
91 | 319 | // then this is the primary module being compiled in a ThinLTO |
92 | 319 | // backend compilation, and we need to see if it has functions that |
93 | 319 | // may be exported to another backend compilation. |
94 | 319 | if (!GlobalsToImport) |
95 | 220 | HasExportedFunctions = ImportIndex.hasExportedFunctions(M); |
96 | 319 | |
97 | | #ifndef NDEBUG |
98 | | // First collect those in the llvm.used set. |
99 | | collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false); |
100 | | // Next collect those in the llvm.compiler.used set. |
101 | | collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ true); |
102 | | #endif |
103 | | } |
104 | | |
105 | | bool run(); |
106 | | |
107 | | static bool doImportAsDefinition(const GlobalValue *SGV, |
108 | | SetVector<GlobalValue *> *GlobalsToImport); |
109 | | }; |
110 | | |
111 | | /// Perform in-place global value handling on the given Module for |
112 | | /// exported local functions renamed and promoted for ThinLTO. |
113 | | bool renameModuleForThinLTO( |
114 | | Module &M, const ModuleSummaryIndex &Index, |
115 | | SetVector<GlobalValue *> *GlobalsToImport = nullptr); |
116 | | |
117 | | } // End llvm namespace |
118 | | |
119 | | #endif |