xref: /llvm-project/clang/lib/Frontend/InitPreprocessor.cpp (revision a4404f21d101fc738e1f99e38d0f83260470464a)
1 //===--- InitPreprocessor.cpp - PP initialization code. ---------*- 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 implements the clang::InitializePreprocessor function.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Frontend/InitPreprocessor.h"
15 #include "clang/Basic/TargetInfo.h"
16 #include "clang/Lex/Preprocessor.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/System/Path.h"
20 
21 namespace clang {
22 
23 // Append a #define line to Buf for Macro.  Macro should be of the form XXX,
24 // in which case we emit "#define XXX 1" or "XXX=Y z W" in which case we emit
25 // "#define XXX Y z W".  To get a #define with no value, use "XXX=".
26 static void DefineBuiltinMacro(std::vector<char> &Buf, const char *Macro,
27                                const char *Command = "#define ") {
28   Buf.insert(Buf.end(), Command, Command+strlen(Command));
29   if (const char *Equal = strchr(Macro, '=')) {
30     // Turn the = into ' '.
31     Buf.insert(Buf.end(), Macro, Equal);
32     Buf.push_back(' ');
33 
34     // Per GCC -D semantics, the macro ends at \n if it exists.
35     const char *End = strpbrk(Equal, "\n\r");
36     if (End) {
37       fprintf(stderr, "warning: macro '%s' contains embedded newline, text "
38               "after the newline is ignored.\n",
39               std::string(Macro, Equal).c_str());
40     } else {
41       End = Equal+strlen(Equal);
42     }
43 
44     Buf.insert(Buf.end(), Equal+1, End);
45   } else {
46     // Push "macroname 1".
47     Buf.insert(Buf.end(), Macro, Macro+strlen(Macro));
48     Buf.push_back(' ');
49     Buf.push_back('1');
50   }
51   Buf.push_back('\n');
52 }
53 
54 // Append a #undef line to Buf for Macro.  Macro should be of the form XXX
55 // and we emit "#undef XXX".
56 static void UndefineBuiltinMacro(std::vector<char> &Buf, const char *Macro) {
57   // Push "macroname".
58   const char *Command = "#undef ";
59   Buf.insert(Buf.end(), Command, Command+strlen(Command));
60   Buf.insert(Buf.end(), Macro, Macro+strlen(Macro));
61   Buf.push_back('\n');
62 }
63 
64 /// Add the quoted name of an implicit include file.
65 static void AddQuotedIncludePath(std::vector<char> &Buf,
66                                  const std::string &File) {
67   // Implicit include paths should be resolved relative to the current
68   // working directory first, and then use the regular header search
69   // mechanism. The proper way to handle this is to have the
70   // predefines buffer located at the current working directory, but
71   // it has not file entry. For now, workaround this by using an
72   // absolute path if we find the file here, and otherwise letting
73   // header search handle it.
74   llvm::sys::Path Path(File);
75   Path.makeAbsolute();
76   if (!Path.exists())
77     Path = File;
78 
79   // Escape double quotes etc.
80   Buf.push_back('"');
81   std::string EscapedFile = Lexer::Stringify(Path.toString());
82   Buf.insert(Buf.end(), EscapedFile.begin(), EscapedFile.end());
83   Buf.push_back('"');
84 }
85 
86 /// AddImplicitInclude - Add an implicit #include of the specified file to the
87 /// predefines buffer.
88 static void AddImplicitInclude(std::vector<char> &Buf,
89                                const std::string &File) {
90   const char *Inc = "#include ";
91   Buf.insert(Buf.end(), Inc, Inc+strlen(Inc));
92   AddQuotedIncludePath(Buf, File);
93   Buf.push_back('\n');
94 }
95 
96 static void AddImplicitIncludeMacros(std::vector<char> &Buf,
97                                      const std::string &File) {
98   const char *Inc = "#__include_macros ";
99   Buf.insert(Buf.end(), Inc, Inc+strlen(Inc));
100   AddQuotedIncludePath(Buf, File);
101   Buf.push_back('\n');
102   // Marker token to stop the __include_macros fetch loop.
103   const char *Marker = "##\n"; // ##?
104   Buf.insert(Buf.end(), Marker, Marker+strlen(Marker));
105 }
106 
107 /// AddImplicitIncludePTH - Add an implicit #include using the original file
108 ///  used to generate a PTH cache.
109 static void AddImplicitIncludePTH(std::vector<char> &Buf, Preprocessor &PP,
110   const std::string& ImplicitIncludePTH) {
111   PTHManager *P = PP.getPTHManager();
112   assert(P && "No PTHManager.");
113   const char *OriginalFile = P->getOriginalSourceFile();
114 
115   if (!OriginalFile) {
116     assert(!ImplicitIncludePTH.empty());
117     fprintf(stderr, "error: PTH file '%s' does not designate an original "
118             "source header file for -include-pth\n",
119             ImplicitIncludePTH.c_str());
120     exit (1);
121   }
122 
123   AddImplicitInclude(Buf, OriginalFile);
124 }
125 
126 /// PickFP - This is used to pick a value based on the FP semantics of the
127 /// specified FP model.
128 template <typename T>
129 static T PickFP(const llvm::fltSemantics *Sem, T IEEESingleVal,
130                 T IEEEDoubleVal, T X87DoubleExtendedVal, T PPCDoubleDoubleVal) {
131   if (Sem == &llvm::APFloat::IEEEsingle)
132     return IEEESingleVal;
133   if (Sem == &llvm::APFloat::IEEEdouble)
134     return IEEEDoubleVal;
135   if (Sem == &llvm::APFloat::x87DoubleExtended)
136     return X87DoubleExtendedVal;
137   assert(Sem == &llvm::APFloat::PPCDoubleDouble);
138   return PPCDoubleDoubleVal;
139 }
140 
141 static void DefineFloatMacros(std::vector<char> &Buf, const char *Prefix,
142                               const llvm::fltSemantics *Sem) {
143   const char *DenormMin, *Epsilon, *Max, *Min;
144   DenormMin = PickFP(Sem, "1.40129846e-45F", "4.9406564584124654e-324",
145                      "3.64519953188247460253e-4951L",
146                      "4.94065645841246544176568792868221e-324L");
147   int Digits = PickFP(Sem, 6, 15, 18, 31);
148   Epsilon = PickFP(Sem, "1.19209290e-7F", "2.2204460492503131e-16",
149                    "1.08420217248550443401e-19L",
150                    "4.94065645841246544176568792868221e-324L");
151   int HasInifinity = 1, HasQuietNaN = 1;
152   int MantissaDigits = PickFP(Sem, 24, 53, 64, 106);
153   int Min10Exp = PickFP(Sem, -37, -307, -4931, -291);
154   int Max10Exp = PickFP(Sem, 38, 308, 4932, 308);
155   int MinExp = PickFP(Sem, -125, -1021, -16381, -968);
156   int MaxExp = PickFP(Sem, 128, 1024, 16384, 1024);
157   Min = PickFP(Sem, "1.17549435e-38F", "2.2250738585072014e-308",
158                "3.36210314311209350626e-4932L",
159                "2.00416836000897277799610805135016e-292L");
160   Max = PickFP(Sem, "3.40282347e+38F", "1.7976931348623157e+308",
161                "1.18973149535723176502e+4932L",
162                "1.79769313486231580793728971405301e+308L");
163 
164   char MacroBuf[60];
165   sprintf(MacroBuf, "__%s_DENORM_MIN__=%s", Prefix, DenormMin);
166   DefineBuiltinMacro(Buf, MacroBuf);
167   sprintf(MacroBuf, "__%s_DIG__=%d", Prefix, Digits);
168   DefineBuiltinMacro(Buf, MacroBuf);
169   sprintf(MacroBuf, "__%s_EPSILON__=%s", Prefix, Epsilon);
170   DefineBuiltinMacro(Buf, MacroBuf);
171   sprintf(MacroBuf, "__%s_HAS_INFINITY__=%d", Prefix, HasInifinity);
172   DefineBuiltinMacro(Buf, MacroBuf);
173   sprintf(MacroBuf, "__%s_HAS_QUIET_NAN__=%d", Prefix, HasQuietNaN);
174   DefineBuiltinMacro(Buf, MacroBuf);
175   sprintf(MacroBuf, "__%s_MANT_DIG__=%d", Prefix, MantissaDigits);
176   DefineBuiltinMacro(Buf, MacroBuf);
177   sprintf(MacroBuf, "__%s_MAX_10_EXP__=%d", Prefix, Max10Exp);
178   DefineBuiltinMacro(Buf, MacroBuf);
179   sprintf(MacroBuf, "__%s_MAX_EXP__=%d", Prefix, MaxExp);
180   DefineBuiltinMacro(Buf, MacroBuf);
181   sprintf(MacroBuf, "__%s_MAX__=%s", Prefix, Max);
182   DefineBuiltinMacro(Buf, MacroBuf);
183   sprintf(MacroBuf, "__%s_MIN_10_EXP__=(%d)", Prefix, Min10Exp);
184   DefineBuiltinMacro(Buf, MacroBuf);
185   sprintf(MacroBuf, "__%s_MIN_EXP__=(%d)", Prefix, MinExp);
186   DefineBuiltinMacro(Buf, MacroBuf);
187   sprintf(MacroBuf, "__%s_MIN__=%s", Prefix, Min);
188   DefineBuiltinMacro(Buf, MacroBuf);
189   sprintf(MacroBuf, "__%s_HAS_DENORM__=1", Prefix);
190   DefineBuiltinMacro(Buf, MacroBuf);
191 }
192 
193 
194 /// DefineTypeSize - Emit a macro to the predefines buffer that declares a macro
195 /// named MacroName with the max value for a type with width 'TypeWidth' a
196 /// signedness of 'isSigned' and with a value suffix of 'ValSuffix' (e.g. LL).
197 static void DefineTypeSize(const char *MacroName, unsigned TypeWidth,
198                            const char *ValSuffix, bool isSigned,
199                            std::vector<char> &Buf) {
200   char MacroBuf[60];
201   long long MaxVal;
202   if (isSigned)
203     MaxVal = (1LL << (TypeWidth - 1)) - 1;
204   else
205     MaxVal = ~0LL >> (64-TypeWidth);
206 
207   sprintf(MacroBuf, "%s=%llu%s", MacroName, MaxVal, ValSuffix);
208   DefineBuiltinMacro(Buf, MacroBuf);
209 }
210 
211 static void DefineType(const char *MacroName, TargetInfo::IntType Ty,
212                        std::vector<char> &Buf) {
213   char MacroBuf[60];
214   sprintf(MacroBuf, "%s=%s", MacroName, TargetInfo::getTypeName(Ty));
215   DefineBuiltinMacro(Buf, MacroBuf);
216 }
217 
218 
219 static void InitializePredefinedMacros(const TargetInfo &TI,
220                                        const LangOptions &LangOpts,
221                                        std::vector<char> &Buf) {
222   char MacroBuf[60];
223   // Compiler version introspection macros.
224   DefineBuiltinMacro(Buf, "__llvm__=1");   // LLVM Backend
225   DefineBuiltinMacro(Buf, "__clang__=1");  // Clang Frontend
226 
227   // Currently claim to be compatible with GCC 4.2.1-5621.
228   DefineBuiltinMacro(Buf, "__APPLE_CC__=5621");
229   DefineBuiltinMacro(Buf, "__GNUC_MINOR__=2");
230   DefineBuiltinMacro(Buf, "__GNUC_PATCHLEVEL__=1");
231   DefineBuiltinMacro(Buf, "__GNUC__=4");
232   DefineBuiltinMacro(Buf, "__GXX_ABI_VERSION=1002");
233   DefineBuiltinMacro(Buf, "__VERSION__=\"4.2.1 Compatible Clang Compiler\"");
234 
235 
236   // Initialize language-specific preprocessor defines.
237 
238   // These should all be defined in the preprocessor according to the
239   // current language configuration.
240   if (!LangOpts.Microsoft)
241     DefineBuiltinMacro(Buf, "__STDC__=1");
242   if (LangOpts.AsmPreprocessor)
243     DefineBuiltinMacro(Buf, "__ASSEMBLER__=1");
244   if (LangOpts.C99 && !LangOpts.CPlusPlus)
245     DefineBuiltinMacro(Buf, "__STDC_VERSION__=199901L");
246   else if (0) // STDC94 ?
247     DefineBuiltinMacro(Buf, "__STDC_VERSION__=199409L");
248 
249   // Standard conforming mode?
250   if (!LangOpts.GNUMode)
251     DefineBuiltinMacro(Buf, "__STRICT_ANSI__=1");
252 
253   if (LangOpts.CPlusPlus0x)
254     DefineBuiltinMacro(Buf, "__GXX_EXPERIMENTAL_CXX0X__");
255 
256   if (LangOpts.Freestanding)
257     DefineBuiltinMacro(Buf, "__STDC_HOSTED__=0");
258   else
259     DefineBuiltinMacro(Buf, "__STDC_HOSTED__=1");
260 
261   if (LangOpts.ObjC1) {
262     DefineBuiltinMacro(Buf, "__OBJC__=1");
263     if (LangOpts.ObjCNonFragileABI) {
264       DefineBuiltinMacro(Buf, "__OBJC2__=1");
265       DefineBuiltinMacro(Buf, "OBJC_ZEROCOST_EXCEPTIONS=1");
266       DefineBuiltinMacro(Buf, "__EXCEPTIONS=1");
267     }
268 
269     if (LangOpts.getGCMode() != LangOptions::NonGC)
270       DefineBuiltinMacro(Buf, "__OBJC_GC__=1");
271 
272     if (LangOpts.NeXTRuntime)
273       DefineBuiltinMacro(Buf, "__NEXT_RUNTIME__=1");
274   }
275 
276   // darwin_constant_cfstrings controls this. This is also dependent
277   // on other things like the runtime I believe.  This is set even for C code.
278   DefineBuiltinMacro(Buf, "__CONSTANT_CFSTRINGS__=1");
279 
280   if (LangOpts.ObjC2)
281     DefineBuiltinMacro(Buf, "OBJC_NEW_PROPERTIES");
282 
283   if (LangOpts.ObjCSenderDispatch)
284     DefineBuiltinMacro(Buf, "__OBJC_SENDER_AWARE_DISPATCH__");
285 
286   if (LangOpts.PascalStrings)
287     DefineBuiltinMacro(Buf, "__PASCAL_STRINGS__");
288 
289   if (LangOpts.Blocks) {
290     DefineBuiltinMacro(Buf, "__block=__attribute__((__blocks__(byref)))");
291     DefineBuiltinMacro(Buf, "__BLOCKS__=1");
292   }
293 
294   if (LangOpts.CPlusPlus) {
295     DefineBuiltinMacro(Buf, "__DEPRECATED=1");
296     DefineBuiltinMacro(Buf, "__EXCEPTIONS=1");
297     DefineBuiltinMacro(Buf, "__GNUG__=4");
298     DefineBuiltinMacro(Buf, "__GXX_WEAK__=1");
299     DefineBuiltinMacro(Buf, "__cplusplus=1");
300     DefineBuiltinMacro(Buf, "__private_extern__=extern");
301   }
302 
303   // Filter out some microsoft extensions when trying to parse in ms-compat
304   // mode.
305   if (LangOpts.Microsoft) {
306     DefineBuiltinMacro(Buf, "_cdecl=__cdecl");
307     DefineBuiltinMacro(Buf, "__int8=__INT8_TYPE__");
308     DefineBuiltinMacro(Buf, "__int16=__INT16_TYPE__");
309     DefineBuiltinMacro(Buf, "__int32=__INT32_TYPE__");
310     DefineBuiltinMacro(Buf, "__int64=__INT64_TYPE__");
311   }
312 
313   if (LangOpts.Optimize)
314     DefineBuiltinMacro(Buf, "__OPTIMIZE__=1");
315   if (LangOpts.OptimizeSize)
316     DefineBuiltinMacro(Buf, "__OPTIMIZE_SIZE__=1");
317 
318   // Initialize target-specific preprocessor defines.
319 
320   // Define type sizing macros based on the target properties.
321   assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
322   DefineBuiltinMacro(Buf, "__CHAR_BIT__=8");
323 
324   unsigned IntMaxWidth;
325   const char *IntMaxSuffix;
326   if (TI.getIntMaxType() == TargetInfo::SignedLongLong) {
327     IntMaxWidth = TI.getLongLongWidth();
328     IntMaxSuffix = "LL";
329   } else if (TI.getIntMaxType() == TargetInfo::SignedLong) {
330     IntMaxWidth = TI.getLongWidth();
331     IntMaxSuffix = "L";
332   } else {
333     assert(TI.getIntMaxType() == TargetInfo::SignedInt);
334     IntMaxWidth = TI.getIntWidth();
335     IntMaxSuffix = "";
336   }
337 
338   DefineTypeSize("__SCHAR_MAX__", TI.getCharWidth(), "", true, Buf);
339   DefineTypeSize("__SHRT_MAX__", TI.getShortWidth(), "", true, Buf);
340   DefineTypeSize("__INT_MAX__", TI.getIntWidth(), "", true, Buf);
341   DefineTypeSize("__LONG_MAX__", TI.getLongWidth(), "L", true, Buf);
342   DefineTypeSize("__LONG_LONG_MAX__", TI.getLongLongWidth(), "LL", true, Buf);
343   DefineTypeSize("__WCHAR_MAX__", TI.getWCharWidth(), "", true, Buf);
344   DefineTypeSize("__INTMAX_MAX__", IntMaxWidth, IntMaxSuffix, true, Buf);
345 
346   DefineType("__INTMAX_TYPE__", TI.getIntMaxType(), Buf);
347   DefineType("__UINTMAX_TYPE__", TI.getUIntMaxType(), Buf);
348   DefineType("__PTRDIFF_TYPE__", TI.getPtrDiffType(0), Buf);
349   DefineType("__INTPTR_TYPE__", TI.getIntPtrType(), Buf);
350   DefineType("__SIZE_TYPE__", TI.getSizeType(), Buf);
351   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Buf);
352   // FIXME: TargetInfo hookize __WINT_TYPE__.
353   DefineBuiltinMacro(Buf, "__WINT_TYPE__=int");
354 
355   DefineFloatMacros(Buf, "FLT", &TI.getFloatFormat());
356   DefineFloatMacros(Buf, "DBL", &TI.getDoubleFormat());
357   DefineFloatMacros(Buf, "LDBL", &TI.getLongDoubleFormat());
358 
359   // Define a __POINTER_WIDTH__ macro for stdint.h.
360   sprintf(MacroBuf, "__POINTER_WIDTH__=%d", (int)TI.getPointerWidth(0));
361   DefineBuiltinMacro(Buf, MacroBuf);
362 
363   if (!TI.isCharSigned())
364     DefineBuiltinMacro(Buf, "__CHAR_UNSIGNED__");
365 
366   // Define fixed-sized integer types for stdint.h
367   assert(TI.getCharWidth() == 8 && "unsupported target types");
368   assert(TI.getShortWidth() == 16 && "unsupported target types");
369   DefineBuiltinMacro(Buf, "__INT8_TYPE__=char");
370   DefineBuiltinMacro(Buf, "__INT16_TYPE__=short");
371 
372   if (TI.getIntWidth() == 32)
373     DefineBuiltinMacro(Buf, "__INT32_TYPE__=int");
374   else {
375     assert(TI.getLongLongWidth() == 32 && "unsupported target types");
376     DefineBuiltinMacro(Buf, "__INT32_TYPE__=long long");
377   }
378 
379   // 16-bit targets doesn't necessarily have a 64-bit type.
380   if (TI.getLongLongWidth() == 64)
381     DefineBuiltinMacro(Buf, "__INT64_TYPE__=long long");
382 
383   // Add __builtin_va_list typedef.
384   {
385     const char *VAList = TI.getVAListDeclaration();
386     Buf.insert(Buf.end(), VAList, VAList+strlen(VAList));
387     Buf.push_back('\n');
388   }
389 
390   if (const char *Prefix = TI.getUserLabelPrefix()) {
391     sprintf(MacroBuf, "__USER_LABEL_PREFIX__=%s", Prefix);
392     DefineBuiltinMacro(Buf, MacroBuf);
393   }
394 
395   // Build configuration options.  FIXME: these should be controlled by
396   // command line options or something.
397   DefineBuiltinMacro(Buf, "__FINITE_MATH_ONLY__=0");
398 
399   if (LangOpts.Static)
400     DefineBuiltinMacro(Buf, "__STATIC__=1");
401   else
402     DefineBuiltinMacro(Buf, "__DYNAMIC__=1");
403 
404   if (LangOpts.GNUInline)
405     DefineBuiltinMacro(Buf, "__GNUC_GNU_INLINE__=1");
406   else
407     DefineBuiltinMacro(Buf, "__GNUC_STDC_INLINE__=1");
408 
409   if (LangOpts.NoInline)
410     DefineBuiltinMacro(Buf, "__NO_INLINE__=1");
411 
412   if (unsigned PICLevel = LangOpts.PICLevel) {
413     sprintf(MacroBuf, "__PIC__=%d", PICLevel);
414     DefineBuiltinMacro(Buf, MacroBuf);
415 
416     sprintf(MacroBuf, "__pic__=%d", PICLevel);
417     DefineBuiltinMacro(Buf, MacroBuf);
418   }
419 
420   // Macros to control C99 numerics and <float.h>
421   DefineBuiltinMacro(Buf, "__FLT_EVAL_METHOD__=0");
422   DefineBuiltinMacro(Buf, "__FLT_RADIX__=2");
423   sprintf(MacroBuf, "__DECIMAL_DIG__=%d",
424           PickFP(&TI.getLongDoubleFormat(), -1/*FIXME*/, 17, 21, 33));
425   DefineBuiltinMacro(Buf, MacroBuf);
426 
427   // Get other target #defines.
428   TI.getTargetDefines(LangOpts, Buf);
429 }
430 
431 /// InitializePreprocessor - Initialize the preprocessor getting it and the
432 /// environment ready to process a single file. This returns true on error.
433 ///
434 bool InitializePreprocessor(Preprocessor &PP,
435                             const PreprocessorInitOptions& InitOpts) {
436   std::vector<char> PredefineBuffer;
437 
438   const char *LineDirective = "# 1 \"<built-in>\" 3\n";
439   PredefineBuffer.insert(PredefineBuffer.end(),
440                          LineDirective, LineDirective+strlen(LineDirective));
441 
442   // Install things like __POWERPC__, __GNUC__, etc into the macro table.
443   InitializePredefinedMacros(PP.getTargetInfo(), PP.getLangOptions(),
444                              PredefineBuffer);
445 
446   // Add on the predefines from the driver.  Wrap in a #line directive to report
447   // that they come from the command line.
448   LineDirective = "# 1 \"<command line>\" 1\n";
449   PredefineBuffer.insert(PredefineBuffer.end(),
450                          LineDirective, LineDirective+strlen(LineDirective));
451 
452   // Process #define's and #undef's in the order they are given.
453   for (PreprocessorInitOptions::macro_iterator I = InitOpts.macro_begin(),
454        E = InitOpts.macro_end(); I != E; ++I) {
455     if (I->second)  // isUndef
456       UndefineBuiltinMacro(PredefineBuffer, I->first.c_str());
457     else
458       DefineBuiltinMacro(PredefineBuffer, I->first.c_str());
459   }
460 
461   // If -imacros are specified, include them now.  These are processed before
462   // any -include directives.
463   for (PreprocessorInitOptions::imacro_iterator I = InitOpts.imacro_begin(),
464        E = InitOpts.imacro_end(); I != E; ++I)
465     AddImplicitIncludeMacros(PredefineBuffer, *I);
466 
467   // Process -include directives.
468   for (PreprocessorInitOptions::include_iterator I = InitOpts.include_begin(),
469        E = InitOpts.include_end(); I != E; ++I) {
470     if (I->second) // isPTH
471       AddImplicitIncludePTH(PredefineBuffer, PP, I->first);
472     else
473       AddImplicitInclude(PredefineBuffer, I->first);
474  }
475 
476   LineDirective = "# 2 \"<built-in>\" 2 3\n";
477   PredefineBuffer.insert(PredefineBuffer.end(),
478                          LineDirective, LineDirective+strlen(LineDirective));
479 
480   // Null terminate PredefinedBuffer and add it.
481   PredefineBuffer.push_back(0);
482   PP.setPredefines(&PredefineBuffer[0]);
483 
484   // Once we've read this, we're done.
485   return false;
486 }
487 
488 } // namespace clang
489