xref: /llvm-project/clang-tools-extra/modularize/PreprocessorTracker.h (revision 282dc72c8b84759dda4fe12420228158962351e8)
1 //===- PreprocessorTracker.h - Tracks preprocessor activities -*- 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 /// \file
10 /// Macro expansions and preprocessor conditional consistency checker.
11 ///
12 //===--------------------------------------------------------------------===//
13 
14 #ifndef MODULARIZE_PREPROCESSOR_TRACKER_H
15 #define MODULARIZE_PREPROCESSOR_TRACKER_H
16 
17 #include "clang/Lex/Preprocessor.h"
18 
19 namespace Modularize {
20 
21 /// Preprocessor tracker for modularize.
22 ///
23 /// The PreprocessorTracker class defines an API for
24 /// checking macro expansions and preprocessor conditional expressions
25 /// in a header file for consistency among one or more compilations of
26 /// the header in a #include scenario.  This is for helping a user
27 /// find which macro expansions or conditionals might be problematic with
28 /// respect to using the headers in the modules scenario, because they
29 /// evaluate to different values depending on how or where a header
30 /// is included.
31 ///
32 /// The handlePreprocessorEntry function implementation will register
33 /// a PPCallbacks object in the given Preprocessor object.  The calls to
34 /// the callbacks will collect information about the macro expansions
35 /// and preprocessor conditionals encountered, for later analysis and
36 /// reporting of inconsistencies between runs performed by calls to
37 /// the reportInconsistentMacros and reportInconsistentConditionals
38 /// functions respectively.  The handlePreprocessorExit informs the
39 /// implementation that a preprocessing session is complete, allowing
40 /// it to do any needed compilation completion activities in the checker.
41 class PreprocessorTracker {
42 public:
43   virtual ~PreprocessorTracker();
44 
45   // Handle entering a preprocessing session.
46   // (Called after a Preprocessor object is created, but before preprocessing.)
47   virtual void handlePreprocessorEntry(clang::Preprocessor &PP,
48                                        llvm::StringRef RootHeaderFile) = 0;
49   // Handle exiting a preprocessing session.
50   // (Called after preprocessing is complete, but before the Preprocessor
51   // object is destroyed.)
52   virtual void handlePreprocessorExit() = 0;
53 
54   // Handle include directive.
55   // This function is called every time an include directive is seen by the
56   // preprocessor, for the purpose of later checking for 'extern "" {}' or
57   // "namespace {}" blocks containing #include directives.
58   virtual void handleIncludeDirective(llvm::StringRef DirectivePath,
59                                       int DirectiveLine, int DirectiveColumn,
60                                       llvm::StringRef TargetPath) = 0;
61 
62   // Check for include directives within the given source line range.
63   // Report errors if any found.  Returns true if no include directives
64   // found in block.
65   virtual bool checkForIncludesInBlock(clang::Preprocessor &PP,
66                                        clang::SourceRange BlockSourceRange,
67                                        const char *BlockIdentifierMessage,
68                                        llvm::raw_ostream &OS) = 0;
69 
70   // Report on inconsistent macro instances.
71   // Returns true if any mismatches.
72   virtual bool reportInconsistentMacros(llvm::raw_ostream &OS) = 0;
73 
74   // Report on inconsistent conditional directive instances.
75   // Returns true if any mismatches.
76   virtual bool reportInconsistentConditionals(llvm::raw_ostream &OS) = 0;
77 
78   // Create instance of PreprocessorTracker.
79   static PreprocessorTracker *create(
80     llvm::SmallVector<std::string, 32> &Headers,
81     bool DoBlockCheckHeaderListOnly);
82 };
83 
84 } // end namespace Modularize
85 
86 #endif
87