1 //===--- PrettyPrinter.h - Classes for aiding with AST printing -*- 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 //  This file defines helper types for AST pretty-printing.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_AST_PRETTYPRINTER_H
14 #define LLVM_CLANG_AST_PRETTYPRINTER_H
15 
16 #include "clang/Basic/LLVM.h"
17 #include "clang/Basic/LangOptions.h"
18 
19 namespace clang {
20 
21 class DeclContext;
22 class LangOptions;
23 class Stmt;
24 
25 class PrinterHelper {
26 public:
27   virtual ~PrinterHelper();
28   virtual bool handledStmt(Stmt* E, raw_ostream& OS) = 0;
29 };
30 
31 /// Callbacks to use to customize the behavior of the pretty-printer.
32 class PrintingCallbacks {
33 protected:
34   ~PrintingCallbacks() = default;
35 
36 public:
37   /// Remap a path to a form suitable for printing.
remapPath(StringRef Path)38   virtual std::string remapPath(StringRef Path) const {
39     return std::string(Path);
40   }
41 
42   /// When printing type to be inserted into code in specific context, this
43   /// callback can be used to avoid printing the redundant part of the
44   /// qualifier. For example, when inserting code inside namespace foo, we
45   /// should print bar::SomeType instead of foo::bar::SomeType.
46   /// To do this, shouldPrintScope should return true on "foo" NamespaceDecl.
47   /// The printing stops at the first isScopeVisible() == true, so there will
48   /// be no calls with outer scopes.
isScopeVisible(const DeclContext * DC)49   virtual bool isScopeVisible(const DeclContext *DC) const { return false; }
50 };
51 
52 /// Describes how types, statements, expressions, and declarations should be
53 /// printed.
54 ///
55 /// This type is intended to be small and suitable for passing by value.
56 /// It is very frequently copied.
57 struct PrintingPolicy {
58   /// Create a default printing policy for the specified language.
PrintingPolicyPrintingPolicy59   PrintingPolicy(const LangOptions &LO)
60       : Indentation(2), SuppressSpecifiers(false),
61         SuppressTagKeyword(LO.CPlusPlus), IncludeTagDefinition(false),
62         SuppressScope(false), SuppressUnwrittenScope(false),
63         SuppressInlineNamespace(true), SuppressInitializers(false),
64         ConstantArraySizeAsWritten(false), AnonymousTagLocations(true),
65         SuppressStrongLifetime(false), SuppressLifetimeQualifiers(false),
66         SuppressTemplateArgsInCXXConstructors(false),
67         SuppressDefaultTemplateArgs(true), Bool(LO.Bool),
68         Nullptr(LO.CPlusPlus11 || LO.C2x), NullptrTypeInNamespace(LO.CPlusPlus),
69         Restrict(LO.C99), Alignof(LO.CPlusPlus11),
70         UnderscoreAlignof(LO.C11), UseVoidForZeroParams(!LO.CPlusPlus),
71         SplitTemplateClosers(!LO.CPlusPlus11), TerseOutput(false),
72         PolishForDeclaration(false), Half(LO.Half),
73         MSWChar(LO.MicrosoftExt && !LO.WChar), IncludeNewlines(true),
74         MSVCFormatting(false), ConstantsAsWritten(false),
75         SuppressImplicitBase(false), FullyQualifiedName(false),
76         PrintCanonicalTypes(false), PrintInjectedClassNameWithArguments(true),
77         UsePreferredNames(true), AlwaysIncludeTypeForTemplateArgument(false),
78         CleanUglifiedParameters(false), EntireContentsOfLargeArray(true),
79         UseEnumerators(true) {}
80 
81   /// Adjust this printing policy for cases where it's known that we're
82   /// printing C++ code (for instance, if AST dumping reaches a C++-only
83   /// construct). This should not be used if a real LangOptions object is
84   /// available.
adjustForCPlusPlusPrintingPolicy85   void adjustForCPlusPlus() {
86     SuppressTagKeyword = true;
87     Bool = true;
88     UseVoidForZeroParams = false;
89   }
90 
91   /// The number of spaces to use to indent each line.
92   unsigned Indentation : 8;
93 
94   /// Whether we should suppress printing of the actual specifiers for
95   /// the given type or declaration.
96   ///
97   /// This flag is only used when we are printing declarators beyond
98   /// the first declarator within a declaration group. For example, given:
99   ///
100   /// \code
101   /// const int *x, *y;
102   /// \endcode
103   ///
104   /// SuppressSpecifiers will be false when printing the
105   /// declaration for "x", so that we will print "int *x"; it will be
106   /// \c true when we print "y", so that we suppress printing the
107   /// "const int" type specifier and instead only print the "*y".
108   unsigned SuppressSpecifiers : 1;
109 
110   /// Whether type printing should skip printing the tag keyword.
111   ///
112   /// This is used when printing the inner type of elaborated types,
113   /// (as the tag keyword is part of the elaborated type):
114   ///
115   /// \code
116   /// struct Geometry::Point;
117   /// \endcode
118   unsigned SuppressTagKeyword : 1;
119 
120   /// When true, include the body of a tag definition.
121   ///
122   /// This is used to place the definition of a struct
123   /// in the middle of another declaration as with:
124   ///
125   /// \code
126   /// typedef struct { int x, y; } Point;
127   /// \endcode
128   unsigned IncludeTagDefinition : 1;
129 
130   /// Suppresses printing of scope specifiers.
131   unsigned SuppressScope : 1;
132 
133   /// Suppress printing parts of scope specifiers that are never
134   /// written, e.g., for anonymous namespaces.
135   unsigned SuppressUnwrittenScope : 1;
136 
137   /// Suppress printing parts of scope specifiers that correspond
138   /// to inline namespaces, where the name is unambiguous with the specifier
139   /// removed.
140   unsigned SuppressInlineNamespace : 1;
141 
142   /// Suppress printing of variable initializers.
143   ///
144   /// This flag is used when printing the loop variable in a for-range
145   /// statement. For example, given:
146   ///
147   /// \code
148   /// for (auto x : coll)
149   /// \endcode
150   ///
151   /// SuppressInitializers will be true when printing "auto x", so that the
152   /// internal initializer constructed for x will not be printed.
153   unsigned SuppressInitializers : 1;
154 
155   /// Whether we should print the sizes of constant array expressions as written
156   /// in the sources.
157   ///
158   /// This flag determines whether array types declared as
159   ///
160   /// \code
161   /// int a[4+10*10];
162   /// char a[] = "A string";
163   /// \endcode
164   ///
165   /// will be printed as written or as follows:
166   ///
167   /// \code
168   /// int a[104];
169   /// char a[9] = "A string";
170   /// \endcode
171   unsigned ConstantArraySizeAsWritten : 1;
172 
173   /// When printing an anonymous tag name, also print the location of that
174   /// entity (e.g., "enum <anonymous at t.h:10:5>"). Otherwise, just prints
175   /// "(anonymous)" for the name.
176   unsigned AnonymousTagLocations : 1;
177 
178   /// When true, suppress printing of the __strong lifetime qualifier in ARC.
179   unsigned SuppressStrongLifetime : 1;
180 
181   /// When true, suppress printing of lifetime qualifier in ARC.
182   unsigned SuppressLifetimeQualifiers : 1;
183 
184   /// When true, suppresses printing template arguments in names of C++
185   /// constructors.
186   unsigned SuppressTemplateArgsInCXXConstructors : 1;
187 
188   /// When true, attempt to suppress template arguments that match the default
189   /// argument for the parameter.
190   unsigned SuppressDefaultTemplateArgs : 1;
191 
192   /// Whether we can use 'bool' rather than '_Bool' (even if the language
193   /// doesn't actually have 'bool', because, e.g., it is defined as a macro).
194   unsigned Bool : 1;
195 
196   /// Whether we should use 'nullptr' rather than '0' as a null pointer
197   /// constant.
198   unsigned Nullptr : 1;
199 
200   /// Whether 'nullptr_t' is in namespace 'std' or not.
201   unsigned NullptrTypeInNamespace : 1;
202 
203   /// Whether we can use 'restrict' rather than '__restrict'.
204   unsigned Restrict : 1;
205 
206   /// Whether we can use 'alignof' rather than '__alignof'.
207   unsigned Alignof : 1;
208 
209   /// Whether we can use '_Alignof' rather than '__alignof'.
210   unsigned UnderscoreAlignof : 1;
211 
212   /// Whether we should use '(void)' rather than '()' for a function prototype
213   /// with zero parameters.
214   unsigned UseVoidForZeroParams : 1;
215 
216   /// Whether nested templates must be closed like 'a\<b\<c\> \>' rather than
217   /// 'a\<b\<c\>\>'.
218   unsigned SplitTemplateClosers : 1;
219 
220   /// Provide a 'terse' output.
221   ///
222   /// For example, in this mode we don't print function bodies, class members,
223   /// declarations inside namespaces etc.  Effectively, this should print
224   /// only the requested declaration.
225   unsigned TerseOutput : 1;
226 
227   /// When true, do certain refinement needed for producing proper declaration
228   /// tag; such as, do not print attributes attached to the declaration.
229   ///
230   unsigned PolishForDeclaration : 1;
231 
232   /// When true, print the half-precision floating-point type as 'half'
233   /// instead of '__fp16'
234   unsigned Half : 1;
235 
236   /// When true, print the built-in wchar_t type as __wchar_t. For use in
237   /// Microsoft mode when wchar_t is not available.
238   unsigned MSWChar : 1;
239 
240   /// When true, include newlines after statements like "break", etc.
241   unsigned IncludeNewlines : 1;
242 
243   /// Use whitespace and punctuation like MSVC does. In particular, this prints
244   /// anonymous namespaces as `anonymous namespace' and does not insert spaces
245   /// after template arguments.
246   unsigned MSVCFormatting : 1;
247 
248   /// Whether we should print the constant expressions as written in the
249   /// sources.
250   ///
251   /// This flag determines whether constants expressions like
252   ///
253   /// \code
254   /// 0x10
255   /// 2.5e3
256   /// \endcode
257   ///
258   /// will be printed as written or as follows:
259   ///
260   /// \code
261   /// 0x10
262   /// 2.5e3
263   /// \endcode
264   unsigned ConstantsAsWritten : 1;
265 
266   /// When true, don't print the implicit 'self' or 'this' expressions.
267   unsigned SuppressImplicitBase : 1;
268 
269   /// When true, print the fully qualified name of function declarations.
270   /// This is the opposite of SuppressScope and thus overrules it.
271   unsigned FullyQualifiedName : 1;
272 
273   /// Whether to print types as written or canonically.
274   unsigned PrintCanonicalTypes : 1;
275 
276   /// Whether to print an InjectedClassNameType with template arguments or as
277   /// written. When a template argument is unnamed, printing it results in
278   /// invalid C++ code.
279   unsigned PrintInjectedClassNameWithArguments : 1;
280 
281   /// Whether to use C++ template preferred_name attributes when printing
282   /// templates.
283   unsigned UsePreferredNames : 1;
284 
285   /// Whether to use type suffixes (eg: 1U) on integral non-type template
286   /// parameters.
287   unsigned AlwaysIncludeTypeForTemplateArgument : 1;
288 
289   /// Whether to strip underscores when printing reserved parameter names.
290   /// e.g. std::vector<class _Tp> becomes std::vector<class Tp>.
291   /// This only affects parameter names, and so describes a compatible API.
292   unsigned CleanUglifiedParameters : 1;
293 
294   /// Whether to print the entire array initializers, especially on non-type
295   /// template parameters, no matter how many elements there are.
296   unsigned EntireContentsOfLargeArray : 1;
297 
298   /// Whether to print enumerator non-type template parameters with a matching
299   /// enumerator name or via cast of an integer.
300   unsigned UseEnumerators : 1;
301 
302   /// Callbacks to use to allow the behavior of printing to be customized.
303   const PrintingCallbacks *Callbacks = nullptr;
304 };
305 
306 } // end namespace clang
307 
308 #endif
309