xref: /llvm-project/clang/lib/Frontend/InitPreprocessor.cpp (revision a1f677c3d16346cbd75bc0055e5e86ddebb269c7)
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/Utils.h"
15 #include "clang/Basic/TargetInfo.h"
16 #include "clang/Frontend/PreprocessorOptions.h"
17 #include "clang/Lex/Preprocessor.h"
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/System/Path.h"
21 using 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 std::string clang::NormalizeDashIncludePath(llvm::StringRef File) {
65   // Implicit include paths should be resolved relative to the current
66   // working directory first, and then use the regular header search
67   // mechanism. The proper way to handle this is to have the
68   // predefines buffer located at the current working directory, but
69   // it has not file entry. For now, workaround this by using an
70   // absolute path if we find the file here, and otherwise letting
71   // header search handle it.
72   llvm::sys::Path Path(File);
73   Path.makeAbsolute();
74   if (!Path.exists())
75     Path = File;
76 
77   return Lexer::Stringify(Path.str());
78 }
79 
80 /// Add the quoted name of an implicit include file.
81 static void AddQuotedIncludePath(std::vector<char> &Buf,
82                                  const std::string &File) {
83 
84   // Escape double quotes etc.
85   Buf.push_back('"');
86   std::string EscapedFile = NormalizeDashIncludePath(File);
87   Buf.insert(Buf.end(), EscapedFile.begin(), EscapedFile.end());
88   Buf.push_back('"');
89 }
90 
91 /// AddImplicitInclude - Add an implicit #include of the specified file to the
92 /// predefines buffer.
93 static void AddImplicitInclude(std::vector<char> &Buf,
94                                const std::string &File) {
95   const char *Inc = "#include ";
96   Buf.insert(Buf.end(), Inc, Inc+strlen(Inc));
97   AddQuotedIncludePath(Buf, File);
98   Buf.push_back('\n');
99 }
100 
101 static void AddImplicitIncludeMacros(std::vector<char> &Buf,
102                                      const std::string &File) {
103   const char *Inc = "#__include_macros ";
104   Buf.insert(Buf.end(), Inc, Inc+strlen(Inc));
105   AddQuotedIncludePath(Buf, File);
106   Buf.push_back('\n');
107   // Marker token to stop the __include_macros fetch loop.
108   const char *Marker = "##\n"; // ##?
109   Buf.insert(Buf.end(), Marker, Marker+strlen(Marker));
110 }
111 
112 /// AddImplicitIncludePTH - Add an implicit #include using the original file
113 ///  used to generate a PTH cache.
114 static void AddImplicitIncludePTH(std::vector<char> &Buf, Preprocessor &PP,
115   const std::string& ImplicitIncludePTH) {
116   PTHManager *P = PP.getPTHManager();
117   assert(P && "No PTHManager.");
118   const char *OriginalFile = P->getOriginalSourceFile();
119 
120   if (!OriginalFile) {
121     assert(!ImplicitIncludePTH.empty());
122     fprintf(stderr, "error: PTH file '%s' does not designate an original "
123             "source header file for -include-pth\n",
124             ImplicitIncludePTH.c_str());
125     exit (1);
126   }
127 
128   AddImplicitInclude(Buf, OriginalFile);
129 }
130 
131 /// PickFP - This is used to pick a value based on the FP semantics of the
132 /// specified FP model.
133 template <typename T>
134 static T PickFP(const llvm::fltSemantics *Sem, T IEEESingleVal,
135                 T IEEEDoubleVal, T X87DoubleExtendedVal, T PPCDoubleDoubleVal,
136                 T IEEEQuadVal) {
137   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEsingle)
138     return IEEESingleVal;
139   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEdouble)
140     return IEEEDoubleVal;
141   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::x87DoubleExtended)
142     return X87DoubleExtendedVal;
143   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::PPCDoubleDouble)
144     return PPCDoubleDoubleVal;
145   assert(Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEquad);
146   return IEEEQuadVal;
147 }
148 
149 static void DefineFloatMacros(std::vector<char> &Buf, const char *Prefix,
150                               const llvm::fltSemantics *Sem) {
151   const char *DenormMin, *Epsilon, *Max, *Min;
152   DenormMin = PickFP(Sem, "1.40129846e-45F", "4.9406564584124654e-324",
153                      "3.64519953188247460253e-4951L",
154                      "4.94065645841246544176568792868221e-324L",
155                      "6.47517511943802511092443895822764655e-4966L");
156   int Digits = PickFP(Sem, 6, 15, 18, 31, 33);
157   Epsilon = PickFP(Sem, "1.19209290e-7F", "2.2204460492503131e-16",
158                    "1.08420217248550443401e-19L",
159                    "4.94065645841246544176568792868221e-324L",
160                    "1.92592994438723585305597794258492732e-34L");
161   int HasInifinity = 1, HasQuietNaN = 1;
162   int MantissaDigits = PickFP(Sem, 24, 53, 64, 106, 113);
163   int Min10Exp = PickFP(Sem, -37, -307, -4931, -291, -4931);
164   int Max10Exp = PickFP(Sem, 38, 308, 4932, 308, 4932);
165   int MinExp = PickFP(Sem, -125, -1021, -16381, -968, -16381);
166   int MaxExp = PickFP(Sem, 128, 1024, 16384, 1024, 16384);
167   Min = PickFP(Sem, "1.17549435e-38F", "2.2250738585072014e-308",
168                "3.36210314311209350626e-4932L",
169                "2.00416836000897277799610805135016e-292L",
170                "3.36210314311209350626267781732175260e-4932L");
171   Max = PickFP(Sem, "3.40282347e+38F", "1.7976931348623157e+308",
172                "1.18973149535723176502e+4932L",
173                "1.79769313486231580793728971405301e+308L",
174                "1.18973149535723176508575932662800702e+4932L");
175 
176   char MacroBuf[100];
177   sprintf(MacroBuf, "__%s_DENORM_MIN__=%s", Prefix, DenormMin);
178   DefineBuiltinMacro(Buf, MacroBuf);
179   sprintf(MacroBuf, "__%s_DIG__=%d", Prefix, Digits);
180   DefineBuiltinMacro(Buf, MacroBuf);
181   sprintf(MacroBuf, "__%s_EPSILON__=%s", Prefix, Epsilon);
182   DefineBuiltinMacro(Buf, MacroBuf);
183   sprintf(MacroBuf, "__%s_HAS_INFINITY__=%d", Prefix, HasInifinity);
184   DefineBuiltinMacro(Buf, MacroBuf);
185   sprintf(MacroBuf, "__%s_HAS_QUIET_NAN__=%d", Prefix, HasQuietNaN);
186   DefineBuiltinMacro(Buf, MacroBuf);
187   sprintf(MacroBuf, "__%s_MANT_DIG__=%d", Prefix, MantissaDigits);
188   DefineBuiltinMacro(Buf, MacroBuf);
189   sprintf(MacroBuf, "__%s_MAX_10_EXP__=%d", Prefix, Max10Exp);
190   DefineBuiltinMacro(Buf, MacroBuf);
191   sprintf(MacroBuf, "__%s_MAX_EXP__=%d", Prefix, MaxExp);
192   DefineBuiltinMacro(Buf, MacroBuf);
193   sprintf(MacroBuf, "__%s_MAX__=%s", Prefix, Max);
194   DefineBuiltinMacro(Buf, MacroBuf);
195   sprintf(MacroBuf, "__%s_MIN_10_EXP__=(%d)", Prefix, Min10Exp);
196   DefineBuiltinMacro(Buf, MacroBuf);
197   sprintf(MacroBuf, "__%s_MIN_EXP__=(%d)", Prefix, MinExp);
198   DefineBuiltinMacro(Buf, MacroBuf);
199   sprintf(MacroBuf, "__%s_MIN__=%s", Prefix, Min);
200   DefineBuiltinMacro(Buf, MacroBuf);
201   sprintf(MacroBuf, "__%s_HAS_DENORM__=1", Prefix);
202   DefineBuiltinMacro(Buf, MacroBuf);
203 }
204 
205 
206 /// DefineTypeSize - Emit a macro to the predefines buffer that declares a macro
207 /// named MacroName with the max value for a type with width 'TypeWidth' a
208 /// signedness of 'isSigned' and with a value suffix of 'ValSuffix' (e.g. LL).
209 static void DefineTypeSize(const char *MacroName, unsigned TypeWidth,
210                            const char *ValSuffix, bool isSigned,
211                            std::vector<char> &Buf) {
212   char MacroBuf[60];
213   long long MaxVal;
214   if (isSigned)
215     MaxVal = (1LL << (TypeWidth - 1)) - 1;
216   else
217     MaxVal = ~0LL >> (64-TypeWidth);
218 
219   // FIXME: Switch to using raw_ostream and avoid utostr().
220   sprintf(MacroBuf, "%s=%s%s", MacroName, llvm::utostr(MaxVal).c_str(),
221           ValSuffix);
222   DefineBuiltinMacro(Buf, MacroBuf);
223 }
224 
225 /// DefineTypeSize - An overloaded helper that uses TargetInfo to determine
226 /// the width, suffix, and signedness of the given type
227 static void DefineTypeSize(const char *MacroName, TargetInfo::IntType Ty,
228                            const TargetInfo &TI, std::vector<char> &Buf) {
229   DefineTypeSize(MacroName, TI.getTypeWidth(Ty), TI.getTypeConstantSuffix(Ty),
230                  TI.isTypeSigned(Ty), Buf);
231 }
232 
233 static void DefineType(const char *MacroName, TargetInfo::IntType Ty,
234                        std::vector<char> &Buf) {
235   char MacroBuf[60];
236   sprintf(MacroBuf, "%s=%s", MacroName, TargetInfo::getTypeName(Ty));
237   DefineBuiltinMacro(Buf, MacroBuf);
238 }
239 
240 static void DefineTypeWidth(const char *MacroName, TargetInfo::IntType Ty,
241                             const TargetInfo &TI, std::vector<char> &Buf) {
242   char MacroBuf[60];
243   sprintf(MacroBuf, "%s=%d", MacroName, TI.getTypeWidth(Ty));
244   DefineBuiltinMacro(Buf, MacroBuf);
245 }
246 
247 static void DefineExactWidthIntType(TargetInfo::IntType Ty,
248                                const TargetInfo &TI, std::vector<char> &Buf) {
249   char MacroBuf[60];
250   int TypeWidth = TI.getTypeWidth(Ty);
251   sprintf(MacroBuf, "__INT%d_TYPE__", TypeWidth);
252   DefineType(MacroBuf, Ty, Buf);
253 
254 
255   const char *ConstSuffix = TargetInfo::getTypeConstantSuffix(Ty);
256   if (strlen(ConstSuffix) > 0) {
257     sprintf(MacroBuf, "__INT%d_C_SUFFIX__=%s", TypeWidth, ConstSuffix);
258     DefineBuiltinMacro(Buf, MacroBuf);
259   }
260 }
261 
262 static void InitializePredefinedMacros(const TargetInfo &TI,
263                                        const LangOptions &LangOpts,
264                                        std::vector<char> &Buf) {
265   char MacroBuf[60];
266   // Compiler version introspection macros.
267   DefineBuiltinMacro(Buf, "__llvm__=1");   // LLVM Backend
268   DefineBuiltinMacro(Buf, "__clang__=1");  // Clang Frontend
269 
270   // Currently claim to be compatible with GCC 4.2.1-5621.
271   DefineBuiltinMacro(Buf, "__GNUC_MINOR__=2");
272   DefineBuiltinMacro(Buf, "__GNUC_PATCHLEVEL__=1");
273   DefineBuiltinMacro(Buf, "__GNUC__=4");
274   DefineBuiltinMacro(Buf, "__GXX_ABI_VERSION=1002");
275   DefineBuiltinMacro(Buf, "__VERSION__=\"4.2.1 Compatible Clang Compiler\"");
276 
277 
278   // Initialize language-specific preprocessor defines.
279 
280   // These should all be defined in the preprocessor according to the
281   // current language configuration.
282   if (!LangOpts.Microsoft)
283     DefineBuiltinMacro(Buf, "__STDC__=1");
284   if (LangOpts.AsmPreprocessor)
285     DefineBuiltinMacro(Buf, "__ASSEMBLER__=1");
286 
287   if (!LangOpts.CPlusPlus) {
288     if (LangOpts.C99)
289       DefineBuiltinMacro(Buf, "__STDC_VERSION__=199901L");
290     else if (!LangOpts.GNUMode && LangOpts.Digraphs)
291       DefineBuiltinMacro(Buf, "__STDC_VERSION__=199409L");
292   }
293 
294   // Standard conforming mode?
295   if (!LangOpts.GNUMode)
296     DefineBuiltinMacro(Buf, "__STRICT_ANSI__=1");
297 
298   if (LangOpts.CPlusPlus0x)
299     DefineBuiltinMacro(Buf, "__GXX_EXPERIMENTAL_CXX0X__");
300 
301   if (LangOpts.Freestanding)
302     DefineBuiltinMacro(Buf, "__STDC_HOSTED__=0");
303   else
304     DefineBuiltinMacro(Buf, "__STDC_HOSTED__=1");
305 
306   if (LangOpts.ObjC1) {
307     DefineBuiltinMacro(Buf, "__OBJC__=1");
308     if (LangOpts.ObjCNonFragileABI) {
309       DefineBuiltinMacro(Buf, "__OBJC2__=1");
310       DefineBuiltinMacro(Buf, "OBJC_ZEROCOST_EXCEPTIONS=1");
311     }
312 
313     if (LangOpts.getGCMode() != LangOptions::NonGC)
314       DefineBuiltinMacro(Buf, "__OBJC_GC__=1");
315 
316     if (LangOpts.NeXTRuntime)
317       DefineBuiltinMacro(Buf, "__NEXT_RUNTIME__=1");
318   }
319 
320   // darwin_constant_cfstrings controls this. This is also dependent
321   // on other things like the runtime I believe.  This is set even for C code.
322   DefineBuiltinMacro(Buf, "__CONSTANT_CFSTRINGS__=1");
323 
324   if (LangOpts.ObjC2)
325     DefineBuiltinMacro(Buf, "OBJC_NEW_PROPERTIES");
326 
327   if (LangOpts.PascalStrings)
328     DefineBuiltinMacro(Buf, "__PASCAL_STRINGS__");
329 
330   if (LangOpts.Blocks) {
331     DefineBuiltinMacro(Buf, "__block=__attribute__((__blocks__(byref)))");
332     DefineBuiltinMacro(Buf, "__BLOCKS__=1");
333   }
334 
335   if (LangOpts.Exceptions)
336     DefineBuiltinMacro(Buf, "__EXCEPTIONS=1");
337 
338   if (LangOpts.CPlusPlus) {
339     DefineBuiltinMacro(Buf, "__DEPRECATED=1");
340     DefineBuiltinMacro(Buf, "__GNUG__=4");
341     DefineBuiltinMacro(Buf, "__GXX_WEAK__=1");
342     if (LangOpts.GNUMode)
343       DefineBuiltinMacro(Buf, "__cplusplus=1");
344     else
345       // C++ [cpp.predefined]p1:
346       //   The name_ _cplusplusis defined to the value199711Lwhen compiling a
347       //   C++ translation unit.
348       DefineBuiltinMacro(Buf, "__cplusplus=199711L");
349     DefineBuiltinMacro(Buf, "__private_extern__=extern");
350     // Ugly hack to work with GNU libstdc++.
351     DefineBuiltinMacro(Buf, "_GNU_SOURCE=1");
352   }
353 
354   if (LangOpts.Microsoft) {
355     // Filter out some microsoft extensions when trying to parse in ms-compat
356     // mode.
357     DefineBuiltinMacro(Buf, "__int8=__INT8_TYPE__");
358     DefineBuiltinMacro(Buf, "__int16=__INT16_TYPE__");
359     DefineBuiltinMacro(Buf, "__int32=__INT32_TYPE__");
360     DefineBuiltinMacro(Buf, "__int64=__INT64_TYPE__");
361     // Work around some issues with Visual C++ headerws.
362     if (LangOpts.CPlusPlus) {
363       // Since we define wchar_t in C++ mode.
364       DefineBuiltinMacro(Buf, "_WCHAR_T_DEFINED=1");
365       DefineBuiltinMacro(Buf, "_NATIVE_WCHAR_T_DEFINED=1");
366       // FIXME:  This should be temporary until we have a __pragma
367       // solution, to avoid some errors flagged in VC++ headers.
368       DefineBuiltinMacro(Buf, "_CRT_SECURE_CPP_OVERLOAD_SECURE_NAMES=0");
369     }
370   }
371 
372   if (LangOpts.Optimize)
373     DefineBuiltinMacro(Buf, "__OPTIMIZE__=1");
374   if (LangOpts.OptimizeSize)
375     DefineBuiltinMacro(Buf, "__OPTIMIZE_SIZE__=1");
376 
377   // Initialize target-specific preprocessor defines.
378 
379   // Define type sizing macros based on the target properties.
380   assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
381   DefineBuiltinMacro(Buf, "__CHAR_BIT__=8");
382 
383   DefineTypeSize("__SCHAR_MAX__", TI.getCharWidth(), "", true, Buf);
384   DefineTypeSize("__SHRT_MAX__", TargetInfo::SignedShort, TI, Buf);
385   DefineTypeSize("__INT_MAX__", TargetInfo::SignedInt, TI, Buf);
386   DefineTypeSize("__LONG_MAX__", TargetInfo::SignedLong, TI, Buf);
387   DefineTypeSize("__LONG_LONG_MAX__", TargetInfo::SignedLongLong, TI, Buf);
388   DefineTypeSize("__WCHAR_MAX__", TI.getWCharType(), TI, Buf);
389   DefineTypeSize("__INTMAX_MAX__", TI.getIntMaxType(), TI, Buf);
390 
391   DefineType("__INTMAX_TYPE__", TI.getIntMaxType(), Buf);
392   DefineType("__UINTMAX_TYPE__", TI.getUIntMaxType(), Buf);
393   DefineTypeWidth("__INTMAX_WIDTH__",  TI.getIntMaxType(), TI, Buf);
394   DefineType("__PTRDIFF_TYPE__", TI.getPtrDiffType(0), Buf);
395   DefineTypeWidth("__PTRDIFF_WIDTH__", TI.getPtrDiffType(0), TI, Buf);
396   DefineType("__INTPTR_TYPE__", TI.getIntPtrType(), Buf);
397   DefineTypeWidth("__INTPTR_WIDTH__", TI.getIntPtrType(), TI, Buf);
398   DefineType("__SIZE_TYPE__", TI.getSizeType(), Buf);
399   DefineTypeWidth("__SIZE_WIDTH__", TI.getSizeType(), TI, Buf);
400   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Buf);
401   DefineType("__WINT_TYPE__", TI.getWIntType(), Buf);
402   DefineTypeWidth("__WINT_WIDTH__", TI.getWIntType(), TI, Buf);
403 
404   DefineFloatMacros(Buf, "FLT", &TI.getFloatFormat());
405   DefineFloatMacros(Buf, "DBL", &TI.getDoubleFormat());
406   DefineFloatMacros(Buf, "LDBL", &TI.getLongDoubleFormat());
407 
408   // Define a __POINTER_WIDTH__ macro for stdint.h.
409   sprintf(MacroBuf, "__POINTER_WIDTH__=%d", (int)TI.getPointerWidth(0));
410   DefineBuiltinMacro(Buf, MacroBuf);
411 
412   if (!LangOpts.CharIsSigned)
413     DefineBuiltinMacro(Buf, "__CHAR_UNSIGNED__");
414 
415   // Define exact-width integer types for stdint.h
416   sprintf(MacroBuf, "__INT%d_TYPE__=char", TI.getCharWidth());
417   DefineBuiltinMacro(Buf, MacroBuf);
418 
419   if (TI.getShortWidth() > TI.getCharWidth())
420     DefineExactWidthIntType(TargetInfo::SignedShort, TI, Buf);
421 
422   if (TI.getIntWidth() > TI.getShortWidth())
423     DefineExactWidthIntType(TargetInfo::SignedInt, TI, Buf);
424 
425   if (TI.getLongWidth() > TI.getIntWidth())
426     DefineExactWidthIntType(TargetInfo::SignedLong, TI, Buf);
427 
428   if (TI.getLongLongWidth() > TI.getLongWidth())
429     DefineExactWidthIntType(TargetInfo::SignedLongLong, TI, Buf);
430 
431   // Add __builtin_va_list typedef.
432   {
433     const char *VAList = TI.getVAListDeclaration();
434     Buf.insert(Buf.end(), VAList, VAList+strlen(VAList));
435     Buf.push_back('\n');
436   }
437 
438   if (const char *Prefix = TI.getUserLabelPrefix()) {
439     sprintf(MacroBuf, "__USER_LABEL_PREFIX__=%s", Prefix);
440     DefineBuiltinMacro(Buf, MacroBuf);
441   }
442 
443   // Build configuration options.  FIXME: these should be controlled by
444   // command line options or something.
445   DefineBuiltinMacro(Buf, "__FINITE_MATH_ONLY__=0");
446 
447   if (LangOpts.GNUInline)
448     DefineBuiltinMacro(Buf, "__GNUC_GNU_INLINE__=1");
449   else
450     DefineBuiltinMacro(Buf, "__GNUC_STDC_INLINE__=1");
451 
452   if (LangOpts.NoInline)
453     DefineBuiltinMacro(Buf, "__NO_INLINE__=1");
454 
455   if (unsigned PICLevel = LangOpts.PICLevel) {
456     sprintf(MacroBuf, "__PIC__=%d", PICLevel);
457     DefineBuiltinMacro(Buf, MacroBuf);
458 
459     sprintf(MacroBuf, "__pic__=%d", PICLevel);
460     DefineBuiltinMacro(Buf, MacroBuf);
461   }
462 
463   // Macros to control C99 numerics and <float.h>
464   DefineBuiltinMacro(Buf, "__FLT_EVAL_METHOD__=0");
465   DefineBuiltinMacro(Buf, "__FLT_RADIX__=2");
466   sprintf(MacroBuf, "__DECIMAL_DIG__=%d",
467           PickFP(&TI.getLongDoubleFormat(), -1/*FIXME*/, 17, 21, 33, 36));
468   DefineBuiltinMacro(Buf, MacroBuf);
469 
470   if (LangOpts.getStackProtectorMode() == LangOptions::SSPOn)
471     DefineBuiltinMacro(Buf, "__SSP__=1");
472   else if (LangOpts.getStackProtectorMode() == LangOptions::SSPReq)
473     DefineBuiltinMacro(Buf, "__SSP_ALL__=2");
474 
475   // Get other target #defines.
476   TI.getTargetDefines(LangOpts, Buf);
477 }
478 
479 /// InitializePreprocessor - Initialize the preprocessor getting it and the
480 /// environment ready to process a single file. This returns true on error.
481 ///
482 void clang::InitializePreprocessor(Preprocessor &PP,
483                                    const PreprocessorOptions &InitOpts,
484                                    const HeaderSearchOptions &HSOpts) {
485   std::vector<char> PredefineBuffer;
486 
487   const char *LineDirective = "# 1 \"<built-in>\" 3\n";
488   PredefineBuffer.insert(PredefineBuffer.end(),
489                          LineDirective, LineDirective+strlen(LineDirective));
490 
491   // Install things like __POWERPC__, __GNUC__, etc into the macro table.
492   if (InitOpts.UsePredefines)
493     InitializePredefinedMacros(PP.getTargetInfo(), PP.getLangOptions(),
494                                PredefineBuffer);
495 
496   // Add on the predefines from the driver.  Wrap in a #line directive to report
497   // that they come from the command line.
498   LineDirective = "# 1 \"<command line>\" 1\n";
499   PredefineBuffer.insert(PredefineBuffer.end(),
500                          LineDirective, LineDirective+strlen(LineDirective));
501 
502   // Process #define's and #undef's in the order they are given.
503   for (unsigned i = 0, e = InitOpts.Macros.size(); i != e; ++i) {
504     if (InitOpts.Macros[i].second)  // isUndef
505       UndefineBuiltinMacro(PredefineBuffer, InitOpts.Macros[i].first.c_str());
506     else
507       DefineBuiltinMacro(PredefineBuffer, InitOpts.Macros[i].first.c_str());
508   }
509 
510   // If -imacros are specified, include them now.  These are processed before
511   // any -include directives.
512   for (unsigned i = 0, e = InitOpts.MacroIncludes.size(); i != e; ++i)
513     AddImplicitIncludeMacros(PredefineBuffer, InitOpts.MacroIncludes[i]);
514 
515   // Process -include directives.
516   for (unsigned i = 0, e = InitOpts.Includes.size(); i != e; ++i) {
517     const std::string &Path = InitOpts.Includes[i];
518     if (Path == InitOpts.ImplicitPTHInclude)
519       AddImplicitIncludePTH(PredefineBuffer, PP, Path);
520     else
521       AddImplicitInclude(PredefineBuffer, Path);
522   }
523 
524   // Null terminate PredefinedBuffer and add it.
525   PredefineBuffer.push_back(0);
526   PP.setPredefines(&PredefineBuffer[0]);
527 
528   // Initialize the header search object.
529   ApplyHeaderSearchOptions(PP.getHeaderSearchInfo(), HSOpts,
530                            PP.getLangOptions(),
531                            PP.getTargetInfo().getTriple());
532 }
533