1 //===- DependencyScanningTool.h - clang-scan-deps service -----------------===//
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 #ifndef LLVM_CLANG_TOOLING_DEPENDENCY_SCANNING_TOOL_H
10 #define LLVM_CLANG_TOOLING_DEPENDENCY_SCANNING_TOOL_H
11 
12 #include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
13 #include "clang/Tooling/DependencyScanning/DependencyScanningWorker.h"
14 #include "clang/Tooling/DependencyScanning/ModuleDepCollector.h"
15 #include "clang/Tooling/JSONCompilationDatabase.h"
16 #include "llvm/ADT/StringSet.h"
17 #include <string>
18 
19 namespace clang{
20 namespace tooling{
21 namespace dependencies{
22 
23 /// The full dependencies and module graph for a specific input.
24 struct FullDependencies {
25   /// The name of the C++20 module this translation unit exports. This may
26   /// include `:` for C++20 module partitons.
27   ///
28   /// If the translation unit is not a module then this will be empty.
29   std::string ExportedModuleName;
30 
31   /// The context hash represents the set of compiler options that may make one
32   /// version of a module incompatible with another. This includes things like
33   /// language mode, predefined macros, header search paths, etc...
34   ///
35   /// Modules with the same name but a different \c ContextHash should be
36   /// treated as separate modules for the purpose of a build.
37   std::string ContextHash;
38 
39   /// A collection of absolute paths to files that this translation unit
40   /// directly depends on, not including transitive dependencies.
41   std::vector<std::string> FileDeps;
42 
43   /// A list of modules this translation unit directly depends on, not including
44   /// transitive dependencies.
45   ///
46   /// This may include modules with a different context hash when it can be
47   /// determined that the differences are benign for this compilation.
48   std::vector<ClangModuleDep> ClangModuleDeps;
49 
50   /// A partial addtional set of command line arguments that can be used to
51   /// build this translation unit.
52   ///
53   /// Call \c getFullAdditionalCommandLine() to get a command line suitable for
54   /// appending to the original command line to pass to clang.
55   std::vector<std::string> AdditionalNonPathCommandLine;
56 
57   /// Gets the full addtional command line suitable for appending to the
58   /// original command line to pass to clang.
59   ///
60   /// \param LookupPCMPath this function is called to fill in `-fmodule-file=`
61   ///                      flags and for the `-o` flag. It needs to return a
62   ///                      path for where the PCM for the given module is to
63   ///                      be located.
64   /// \param LookupModuleDeps this fucntion is called to collect the full
65   ///                         transitive set of dependencies for this
66   ///                         compilation.
67   std::vector<std::string> getAdditionalCommandLine(
68       std::function<StringRef(ClangModuleDep)> LookupPCMPath,
69       std::function<const ModuleDeps &(ClangModuleDep)> LookupModuleDeps) const;
70 };
71 
72 struct FullDependenciesResult {
73   FullDependencies FullDeps;
74   std::vector<ModuleDeps> DiscoveredModules;
75 };
76 
77 /// The high-level implementation of the dependency discovery tool that runs on
78 /// an individual worker thread.
79 class DependencyScanningTool {
80 public:
81   /// Construct a dependency scanning tool.
82   DependencyScanningTool(DependencyScanningService &Service);
83 
84   /// Print out the dependency information into a string using the dependency
85   /// file format that is specified in the options (-MD is the default) and
86   /// return it.
87   ///
88   /// \returns A \c StringError with the diagnostic output if clang errors
89   /// occurred, dependency file contents otherwise.
90   llvm::Expected<std::string>
91   getDependencyFile(const tooling::CompilationDatabase &Compilations,
92                     StringRef CWD);
93 
94   /// Collect the full module depenedency graph for the input, ignoring any
95   /// modules which have already been seen.
96   ///
97   /// \param AlreadySeen this is used to not report modules that have previously
98   ///                    been reported. Use the same `llvm::StringSet<>` for all
99   ///                    calls to `getFullDependencies` for a single
100   ///                    `DependencyScanningTool` for a single build. Use a
101   ///                    different one for different tools, and clear it between
102   ///                    builds.
103   ///
104   /// \returns a \c StringError with the diagnostic output if clang errors
105   /// occurred, \c FullDependencies otherwise.
106   llvm::Expected<FullDependenciesResult>
107   getFullDependencies(const tooling::CompilationDatabase &Compilations,
108                       StringRef CWD, const llvm::StringSet<> &AlreadySeen);
109 
110 private:
111   DependencyScanningWorker Worker;
112 };
113 
114 } // end namespace dependencies
115 } // end namespace tooling
116 } // end namespace clang
117 
118 #endif // LLVM_CLANG_TOOLING_DEPENDENCY_SCANNING_TOOL_H
119