1 //===--- LiteralSupport.h ---------------------------------------*- 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 the NumericLiteralParser, CharLiteralParser, and
10 // StringLiteralParser interfaces.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LEX_LITERALSUPPORT_H
15 #define LLVM_CLANG_LEX_LITERALSUPPORT_H
16 
17 #include "clang/Basic/CharInfo.h"
18 #include "clang/Basic/LLVM.h"
19 #include "clang/Basic/TokenKinds.h"
20 #include "llvm/ADT/APFloat.h"
21 #include "llvm/ADT/ArrayRef.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/StringRef.h"
24 #include "llvm/Support/DataTypes.h"
25 
26 namespace clang {
27 
28 class DiagnosticsEngine;
29 class Preprocessor;
30 class Token;
31 class SourceLocation;
32 class TargetInfo;
33 class SourceManager;
34 class LangOptions;
35 
36 /// Copy characters from Input to Buf, expanding any UCNs.
37 void expandUCNs(SmallVectorImpl<char> &Buf, StringRef Input);
38 
39 /// Return true if the token corresponds to a function local predefined macro,
40 /// which expands to a string literal, that can be concatenated with other
41 /// string literals (only in Microsoft mode).
42 bool isFunctionLocalStringLiteralMacro(tok::TokenKind K, const LangOptions &LO);
43 
44 /// Return true if the token is a string literal, or a function local
45 /// predefined macro, which expands to a string literal.
46 bool tokenIsLikeStringLiteral(const Token &Tok, const LangOptions &LO);
47 
48 /// NumericLiteralParser - This performs strict semantic analysis of the content
49 /// of a ppnumber, classifying it as either integer, floating, or erroneous,
50 /// determines the radix of the value and can convert it to a useful value.
51 class NumericLiteralParser {
52   const SourceManager &SM;
53   const LangOptions &LangOpts;
54   DiagnosticsEngine &Diags;
55 
56   const char *const ThisTokBegin;
57   const char *const ThisTokEnd;
58   const char *DigitsBegin, *SuffixBegin; // markers
59   const char *s; // cursor
60 
61   unsigned radix;
62 
63   bool saw_exponent, saw_period, saw_ud_suffix, saw_fixed_point_suffix;
64 
65   SmallString<32> UDSuffixBuf;
66 
67 public:
68   NumericLiteralParser(StringRef TokSpelling, SourceLocation TokLoc,
69                        const SourceManager &SM, const LangOptions &LangOpts,
70                        const TargetInfo &Target, DiagnosticsEngine &Diags);
71   bool hadError : 1;
72   bool isUnsigned : 1;
73   bool isLong : 1;          // This is *not* set for long long.
74   bool isLongLong : 1;
75   bool isSizeT : 1;         // 1z, 1uz (C++23)
76   bool isHalf : 1;          // 1.0h
77   bool isFloat : 1;         // 1.0f
78   bool isImaginary : 1;     // 1.0i
79   bool isFloat16 : 1;       // 1.0f16
80   bool isFloat128 : 1;      // 1.0q
81   bool isFract : 1;         // 1.0hr/r/lr/uhr/ur/ulr
82   bool isAccum : 1;         // 1.0hk/k/lk/uhk/uk/ulk
83   bool isBitInt : 1;        // 1wb, 1uwb (C23)
84   uint8_t MicrosoftInteger; // Microsoft suffix extension i8, i16, i32, or i64.
85 
86 
87   bool isFixedPointLiteral() const {
88     return (saw_period || saw_exponent) && saw_fixed_point_suffix;
89   }
90 
91   bool isIntegerLiteral() const {
92     return !saw_period && !saw_exponent && !isFixedPointLiteral();
93   }
94   bool isFloatingLiteral() const {
95     return (saw_period || saw_exponent) && !isFixedPointLiteral();
96   }
97 
98   bool hasUDSuffix() const {
99     return saw_ud_suffix;
100   }
101   StringRef getUDSuffix() const {
102     assert(saw_ud_suffix);
103     return UDSuffixBuf;
104   }
105   unsigned getUDSuffixOffset() const {
106     assert(saw_ud_suffix);
107     return SuffixBegin - ThisTokBegin;
108   }
109 
110   static bool isValidUDSuffix(const LangOptions &LangOpts, StringRef Suffix);
111 
112   unsigned getRadix() const { return radix; }
113 
114   /// GetIntegerValue - Convert this numeric literal value to an APInt that
115   /// matches Val's input width.  If there is an overflow (i.e., if the unsigned
116   /// value read is larger than the APInt's bits will hold), set Val to the low
117   /// bits of the result and return true.  Otherwise, return false.
118   bool GetIntegerValue(llvm::APInt &Val);
119 
120   /// GetFloatValue - Convert this numeric literal to a floating value, using
121   /// the specified APFloat fltSemantics (specifying float, double, etc).
122   /// The optional bool isExact (passed-by-reference) has its value
123   /// set to true if the returned APFloat can represent the number in the
124   /// literal exactly, and false otherwise.
125   llvm::APFloat::opStatus GetFloatValue(llvm::APFloat &Result);
126 
127   /// GetFixedPointValue - Convert this numeric literal value into a
128   /// scaled integer that represents this value. Returns true if an overflow
129   /// occurred when calculating the integral part of the scaled integer or
130   /// calculating the digit sequence of the exponent.
131   bool GetFixedPointValue(llvm::APInt &StoreVal, unsigned Scale);
132 
133   /// Get the digits that comprise the literal. This excludes any prefix or
134   /// suffix associated with the literal.
135   StringRef getLiteralDigits() const {
136     assert(!hadError && "cannot reliably get the literal digits with an error");
137     return StringRef(DigitsBegin, SuffixBegin - DigitsBegin);
138   }
139 
140 private:
141 
142   void ParseNumberStartingWithZero(SourceLocation TokLoc);
143   void ParseDecimalOrOctalCommon(SourceLocation TokLoc);
144 
145   static bool isDigitSeparator(char C) { return C == '\''; }
146 
147   /// Determine whether the sequence of characters [Start, End) contains
148   /// any real digits (not digit separators).
149   bool containsDigits(const char *Start, const char *End) {
150     return Start != End && (Start + 1 != End || !isDigitSeparator(Start[0]));
151   }
152 
153   enum CheckSeparatorKind { CSK_BeforeDigits, CSK_AfterDigits };
154 
155   /// Ensure that we don't have a digit separator here.
156   void checkSeparator(SourceLocation TokLoc, const char *Pos,
157                       CheckSeparatorKind IsAfterDigits);
158 
159   /// SkipHexDigits - Read and skip over any hex digits, up to End.
160   /// Return a pointer to the first non-hex digit or End.
161   const char *SkipHexDigits(const char *ptr) {
162     while (ptr != ThisTokEnd && (isHexDigit(*ptr) || isDigitSeparator(*ptr)))
163       ptr++;
164     return ptr;
165   }
166 
167   /// SkipOctalDigits - Read and skip over any octal digits, up to End.
168   /// Return a pointer to the first non-hex digit or End.
169   const char *SkipOctalDigits(const char *ptr) {
170     while (ptr != ThisTokEnd &&
171            ((*ptr >= '0' && *ptr <= '7') || isDigitSeparator(*ptr)))
172       ptr++;
173     return ptr;
174   }
175 
176   /// SkipDigits - Read and skip over any digits, up to End.
177   /// Return a pointer to the first non-hex digit or End.
178   const char *SkipDigits(const char *ptr) {
179     while (ptr != ThisTokEnd && (isDigit(*ptr) || isDigitSeparator(*ptr)))
180       ptr++;
181     return ptr;
182   }
183 
184   /// SkipBinaryDigits - Read and skip over any binary digits, up to End.
185   /// Return a pointer to the first non-binary digit or End.
186   const char *SkipBinaryDigits(const char *ptr) {
187     while (ptr != ThisTokEnd &&
188            (*ptr == '0' || *ptr == '1' || isDigitSeparator(*ptr)))
189       ptr++;
190     return ptr;
191   }
192 
193 };
194 
195 /// CharLiteralParser - Perform interpretation and semantic analysis of a
196 /// character literal.
197 class CharLiteralParser {
198   uint64_t Value;
199   tok::TokenKind Kind;
200   bool IsMultiChar;
201   bool HadError;
202   SmallString<32> UDSuffixBuf;
203   unsigned UDSuffixOffset;
204 public:
205   CharLiteralParser(const char *begin, const char *end,
206                     SourceLocation Loc, Preprocessor &PP,
207                     tok::TokenKind kind);
208 
209   bool hadError() const { return HadError; }
210   bool isOrdinary() const { return Kind == tok::char_constant; }
211   bool isWide() const { return Kind == tok::wide_char_constant; }
212   bool isUTF8() const { return Kind == tok::utf8_char_constant; }
213   bool isUTF16() const { return Kind == tok::utf16_char_constant; }
214   bool isUTF32() const { return Kind == tok::utf32_char_constant; }
215   bool isMultiChar() const { return IsMultiChar; }
216   uint64_t getValue() const { return Value; }
217   StringRef getUDSuffix() const { return UDSuffixBuf; }
218   unsigned getUDSuffixOffset() const {
219     assert(!UDSuffixBuf.empty() && "no ud-suffix");
220     return UDSuffixOffset;
221   }
222 };
223 
224 enum class StringLiteralEvalMethod {
225   Evaluated,
226   Unevaluated,
227 };
228 
229 /// StringLiteralParser - This decodes string escape characters and performs
230 /// wide string analysis and Translation Phase #6 (concatenation of string
231 /// literals) (C99 5.1.1.2p1).
232 class StringLiteralParser {
233   const SourceManager &SM;
234   const LangOptions &Features;
235   const TargetInfo &Target;
236   DiagnosticsEngine *Diags;
237 
238   unsigned MaxTokenLength;
239   unsigned SizeBound;
240   unsigned CharByteWidth;
241   tok::TokenKind Kind;
242   SmallString<512> ResultBuf;
243   char *ResultPtr; // cursor
244   SmallString<32> UDSuffixBuf;
245   unsigned UDSuffixToken;
246   unsigned UDSuffixOffset;
247   StringLiteralEvalMethod EvalMethod;
248 
249 public:
250   StringLiteralParser(ArrayRef<Token> StringToks, Preprocessor &PP,
251                       StringLiteralEvalMethod StringMethod =
252                           StringLiteralEvalMethod::Evaluated);
253   StringLiteralParser(ArrayRef<Token> StringToks, const SourceManager &sm,
254                       const LangOptions &features, const TargetInfo &target,
255                       DiagnosticsEngine *diags = nullptr)
256       : SM(sm), Features(features), Target(target), Diags(diags),
257         MaxTokenLength(0), SizeBound(0), CharByteWidth(0), Kind(tok::unknown),
258         ResultPtr(ResultBuf.data()),
259         EvalMethod(StringLiteralEvalMethod::Evaluated), hadError(false),
260         Pascal(false) {
261     init(StringToks);
262   }
263 
264   bool hadError;
265   bool Pascal;
266 
267   StringRef GetString() const {
268     return StringRef(ResultBuf.data(), GetStringLength());
269   }
270   unsigned GetStringLength() const { return ResultPtr-ResultBuf.data(); }
271 
272   unsigned GetNumStringChars() const {
273     return GetStringLength() / CharByteWidth;
274   }
275   /// getOffsetOfStringByte - This function returns the offset of the
276   /// specified byte of the string data represented by Token.  This handles
277   /// advancing over escape sequences in the string.
278   ///
279   /// If the Diagnostics pointer is non-null, then this will do semantic
280   /// checking of the string literal and emit errors and warnings.
281   unsigned getOffsetOfStringByte(const Token &TheTok, unsigned ByteNo) const;
282 
283   bool isOrdinary() const { return Kind == tok::string_literal; }
284   bool isWide() const { return Kind == tok::wide_string_literal; }
285   bool isUTF8() const { return Kind == tok::utf8_string_literal; }
286   bool isUTF16() const { return Kind == tok::utf16_string_literal; }
287   bool isUTF32() const { return Kind == tok::utf32_string_literal; }
288   bool isPascal() const { return Pascal; }
289   bool isUnevaluated() const {
290     return EvalMethod == StringLiteralEvalMethod::Unevaluated;
291   }
292 
293   StringRef getUDSuffix() const { return UDSuffixBuf; }
294 
295   /// Get the index of a token containing a ud-suffix.
296   unsigned getUDSuffixToken() const {
297     assert(!UDSuffixBuf.empty() && "no ud-suffix");
298     return UDSuffixToken;
299   }
300   /// Get the spelling offset of the first byte of the ud-suffix.
301   unsigned getUDSuffixOffset() const {
302     assert(!UDSuffixBuf.empty() && "no ud-suffix");
303     return UDSuffixOffset;
304   }
305 
306   static bool isValidUDSuffix(const LangOptions &LangOpts, StringRef Suffix);
307 
308 private:
309   void init(ArrayRef<Token> StringToks);
310   bool CopyStringFragment(const Token &Tok, const char *TokBegin,
311                           StringRef Fragment);
312   void DiagnoseLexingError(SourceLocation Loc);
313 };
314 
315 }  // end namespace clang
316 
317 #endif
318