xref: /llvm-project/clang/lib/Frontend/InitPreprocessor.cpp (revision 61fbf6283816f4d9b8539cdc17bc147ed596281e)
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/Basic/Version.h"
15 #include "clang/Frontend/Utils.h"
16 #include "clang/Basic/MacroBuilder.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Frontend/FrontendDiagnostic.h"
19 #include "clang/Frontend/FrontendOptions.h"
20 #include "clang/Frontend/PreprocessorOptions.h"
21 #include "clang/Lex/Preprocessor.h"
22 #include "clang/Basic/FileManager.h"
23 #include "clang/Basic/SourceManager.h"
24 #include "llvm/ADT/APFloat.h"
25 #include "llvm/Support/FileSystem.h"
26 #include "llvm/Support/MemoryBuffer.h"
27 #include "llvm/Support/Path.h"
28 using namespace clang;
29 
30 // Append a #define line to Buf for Macro.  Macro should be of the form XXX,
31 // in which case we emit "#define XXX 1" or "XXX=Y z W" in which case we emit
32 // "#define XXX Y z W".  To get a #define with no value, use "XXX=".
33 static void DefineBuiltinMacro(MacroBuilder &Builder, llvm::StringRef Macro,
34                                Diagnostic &Diags) {
35   std::pair<llvm::StringRef, llvm::StringRef> MacroPair = Macro.split('=');
36   llvm::StringRef MacroName = MacroPair.first;
37   llvm::StringRef MacroBody = MacroPair.second;
38   if (MacroName.size() != Macro.size()) {
39     // Per GCC -D semantics, the macro ends at \n if it exists.
40     llvm::StringRef::size_type End = MacroBody.find_first_of("\n\r");
41     if (End != llvm::StringRef::npos)
42       Diags.Report(diag::warn_fe_macro_contains_embedded_newline)
43         << MacroName;
44     Builder.defineMacro(MacroName, MacroBody.substr(0, End));
45   } else {
46     // Push "macroname 1".
47     Builder.defineMacro(Macro);
48   }
49 }
50 
51 std::string clang::NormalizeDashIncludePath(llvm::StringRef File,
52                                             FileManager &FileMgr) {
53   // Implicit include paths should be resolved relative to the current
54   // working directory first, and then use the regular header search
55   // mechanism. The proper way to handle this is to have the
56   // predefines buffer located at the current working directory, but
57   // it has no file entry. For now, workaround this by using an
58   // absolute path if we find the file here, and otherwise letting
59   // header search handle it.
60   llvm::SmallString<128> Path(File);
61   llvm::sys::fs::make_absolute(Path);
62   bool exists;
63   if (llvm::sys::fs::exists(Path.str(), exists) || !exists)
64     Path = File;
65   else if (exists)
66     FileMgr.getFile(File);
67 
68   return Lexer::Stringify(Path.str());
69 }
70 
71 /// AddImplicitInclude - Add an implicit #include of the specified file to the
72 /// predefines buffer.
73 static void AddImplicitInclude(MacroBuilder &Builder, llvm::StringRef File,
74                                FileManager &FileMgr) {
75   Builder.append("#include \"" +
76                  llvm::Twine(NormalizeDashIncludePath(File, FileMgr)) + "\"");
77 }
78 
79 static void AddImplicitIncludeMacros(MacroBuilder &Builder,
80                                      llvm::StringRef File,
81                                      FileManager &FileMgr) {
82   Builder.append("#__include_macros \"" +
83                  llvm::Twine(NormalizeDashIncludePath(File, FileMgr)) + "\"");
84   // Marker token to stop the __include_macros fetch loop.
85   Builder.append("##"); // ##?
86 }
87 
88 /// AddImplicitIncludePTH - Add an implicit #include using the original file
89 ///  used to generate a PTH cache.
90 static void AddImplicitIncludePTH(MacroBuilder &Builder, Preprocessor &PP,
91                                   llvm::StringRef ImplicitIncludePTH) {
92   PTHManager *P = PP.getPTHManager();
93   // Null check 'P' in the corner case where it couldn't be created.
94   const char *OriginalFile = P ? P->getOriginalSourceFile() : 0;
95 
96   if (!OriginalFile) {
97     PP.getDiagnostics().Report(diag::err_fe_pth_file_has_no_source_header)
98       << ImplicitIncludePTH;
99     return;
100   }
101 
102   AddImplicitInclude(Builder, OriginalFile, PP.getFileManager());
103 }
104 
105 /// PickFP - This is used to pick a value based on the FP semantics of the
106 /// specified FP model.
107 template <typename T>
108 static T PickFP(const llvm::fltSemantics *Sem, T IEEESingleVal,
109                 T IEEEDoubleVal, T X87DoubleExtendedVal, T PPCDoubleDoubleVal,
110                 T IEEEQuadVal) {
111   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEsingle)
112     return IEEESingleVal;
113   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEdouble)
114     return IEEEDoubleVal;
115   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::x87DoubleExtended)
116     return X87DoubleExtendedVal;
117   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::PPCDoubleDouble)
118     return PPCDoubleDoubleVal;
119   assert(Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEquad);
120   return IEEEQuadVal;
121 }
122 
123 static void DefineFloatMacros(MacroBuilder &Builder, llvm::StringRef Prefix,
124                               const llvm::fltSemantics *Sem) {
125   const char *DenormMin, *Epsilon, *Max, *Min;
126   DenormMin = PickFP(Sem, "1.40129846e-45F", "4.9406564584124654e-324",
127                      "3.64519953188247460253e-4951L",
128                      "4.94065645841246544176568792868221e-324L",
129                      "6.47517511943802511092443895822764655e-4966L");
130   int Digits = PickFP(Sem, 6, 15, 18, 31, 33);
131   Epsilon = PickFP(Sem, "1.19209290e-7F", "2.2204460492503131e-16",
132                    "1.08420217248550443401e-19L",
133                    "4.94065645841246544176568792868221e-324L",
134                    "1.92592994438723585305597794258492732e-34L");
135   int MantissaDigits = PickFP(Sem, 24, 53, 64, 106, 113);
136   int Min10Exp = PickFP(Sem, -37, -307, -4931, -291, -4931);
137   int Max10Exp = PickFP(Sem, 38, 308, 4932, 308, 4932);
138   int MinExp = PickFP(Sem, -125, -1021, -16381, -968, -16381);
139   int MaxExp = PickFP(Sem, 128, 1024, 16384, 1024, 16384);
140   Min = PickFP(Sem, "1.17549435e-38F", "2.2250738585072014e-308",
141                "3.36210314311209350626e-4932L",
142                "2.00416836000897277799610805135016e-292L",
143                "3.36210314311209350626267781732175260e-4932L");
144   Max = PickFP(Sem, "3.40282347e+38F", "1.7976931348623157e+308",
145                "1.18973149535723176502e+4932L",
146                "1.79769313486231580793728971405301e+308L",
147                "1.18973149535723176508575932662800702e+4932L");
148 
149   llvm::SmallString<32> DefPrefix;
150   DefPrefix = "__";
151   DefPrefix += Prefix;
152   DefPrefix += "_";
153 
154   Builder.defineMacro(DefPrefix + "DENORM_MIN__", DenormMin);
155   Builder.defineMacro(DefPrefix + "HAS_DENORM__");
156   Builder.defineMacro(DefPrefix + "DIG__", llvm::Twine(Digits));
157   Builder.defineMacro(DefPrefix + "EPSILON__", llvm::Twine(Epsilon));
158   Builder.defineMacro(DefPrefix + "HAS_INFINITY__");
159   Builder.defineMacro(DefPrefix + "HAS_QUIET_NAN__");
160   Builder.defineMacro(DefPrefix + "MANT_DIG__", llvm::Twine(MantissaDigits));
161 
162   Builder.defineMacro(DefPrefix + "MAX_10_EXP__", llvm::Twine(Max10Exp));
163   Builder.defineMacro(DefPrefix + "MAX_EXP__", llvm::Twine(MaxExp));
164   Builder.defineMacro(DefPrefix + "MAX__", llvm::Twine(Max));
165 
166   Builder.defineMacro(DefPrefix + "MIN_10_EXP__","("+llvm::Twine(Min10Exp)+")");
167   Builder.defineMacro(DefPrefix + "MIN_EXP__", "("+llvm::Twine(MinExp)+")");
168   Builder.defineMacro(DefPrefix + "MIN__", llvm::Twine(Min));
169 }
170 
171 
172 /// DefineTypeSize - Emit a macro to the predefines buffer that declares a macro
173 /// named MacroName with the max value for a type with width 'TypeWidth' a
174 /// signedness of 'isSigned' and with a value suffix of 'ValSuffix' (e.g. LL).
175 static void DefineTypeSize(llvm::StringRef MacroName, unsigned TypeWidth,
176                            llvm::StringRef ValSuffix, bool isSigned,
177                            MacroBuilder &Builder) {
178   llvm::APInt MaxVal = isSigned ? llvm::APInt::getSignedMaxValue(TypeWidth)
179                                 : llvm::APInt::getMaxValue(TypeWidth);
180   Builder.defineMacro(MacroName, MaxVal.toString(10, isSigned) + ValSuffix);
181 }
182 
183 /// DefineTypeSize - An overloaded helper that uses TargetInfo to determine
184 /// the width, suffix, and signedness of the given type
185 static void DefineTypeSize(llvm::StringRef MacroName, TargetInfo::IntType Ty,
186                            const TargetInfo &TI, MacroBuilder &Builder) {
187   DefineTypeSize(MacroName, TI.getTypeWidth(Ty), TI.getTypeConstantSuffix(Ty),
188                  TI.isTypeSigned(Ty), Builder);
189 }
190 
191 static void DefineType(const llvm::Twine &MacroName, TargetInfo::IntType Ty,
192                        MacroBuilder &Builder) {
193   Builder.defineMacro(MacroName, TargetInfo::getTypeName(Ty));
194 }
195 
196 static void DefineTypeWidth(llvm::StringRef MacroName, TargetInfo::IntType Ty,
197                             const TargetInfo &TI, MacroBuilder &Builder) {
198   Builder.defineMacro(MacroName, llvm::Twine(TI.getTypeWidth(Ty)));
199 }
200 
201 static void DefineTypeSizeof(llvm::StringRef MacroName, unsigned BitWidth,
202                              const TargetInfo &TI, MacroBuilder &Builder) {
203   Builder.defineMacro(MacroName,
204                       llvm::Twine(BitWidth / TI.getCharWidth()));
205 }
206 
207 static void DefineExactWidthIntType(TargetInfo::IntType Ty,
208                                const TargetInfo &TI, MacroBuilder &Builder) {
209   int TypeWidth = TI.getTypeWidth(Ty);
210 
211   // Use the target specified int64 type, when appropriate, so that [u]int64_t
212   // ends up being defined in terms of the correct type.
213   if (TypeWidth == 64)
214     Ty = TI.getInt64Type();
215 
216   DefineType("__INT" + llvm::Twine(TypeWidth) + "_TYPE__", Ty, Builder);
217 
218   llvm::StringRef ConstSuffix(TargetInfo::getTypeConstantSuffix(Ty));
219   if (!ConstSuffix.empty())
220     Builder.defineMacro("__INT" + llvm::Twine(TypeWidth) + "_C_SUFFIX__",
221                         ConstSuffix);
222 }
223 
224 static void InitializePredefinedMacros(const TargetInfo &TI,
225                                        const LangOptions &LangOpts,
226                                        const FrontendOptions &FEOpts,
227                                        MacroBuilder &Builder) {
228   // Compiler version introspection macros.
229   Builder.defineMacro("__llvm__");  // LLVM Backend
230   Builder.defineMacro("__clang__"); // Clang Frontend
231 #define TOSTR2(X) #X
232 #define TOSTR(X) TOSTR2(X)
233   Builder.defineMacro("__clang_major__", TOSTR(CLANG_VERSION_MAJOR));
234   Builder.defineMacro("__clang_minor__", TOSTR(CLANG_VERSION_MINOR));
235 #ifdef CLANG_VERSION_PATCHLEVEL
236   Builder.defineMacro("__clang_patchlevel__", TOSTR(CLANG_VERSION_PATCHLEVEL));
237 #else
238   Builder.defineMacro("__clang_patchlevel__", "0");
239 #endif
240   Builder.defineMacro("__clang_version__",
241                       "\"" CLANG_VERSION_STRING " ("
242                       + getClangFullRepositoryVersion() + ")\"");
243 #undef TOSTR
244 #undef TOSTR2
245   // Currently claim to be compatible with GCC 4.2.1-5621.
246   Builder.defineMacro("__GNUC_MINOR__", "2");
247   Builder.defineMacro("__GNUC_PATCHLEVEL__", "1");
248   Builder.defineMacro("__GNUC__", "4");
249   Builder.defineMacro("__GXX_ABI_VERSION", "1002");
250 
251   // As sad as it is, enough software depends on the __VERSION__ for version
252   // checks that it is necessary to report 4.2.1 (the base GCC version we claim
253   // compatibility with) first.
254   Builder.defineMacro("__VERSION__", "\"4.2.1 Compatible " +
255                       llvm::Twine(getClangFullCPPVersion()) + "\"");
256 
257   // Initialize language-specific preprocessor defines.
258 
259   // These should all be defined in the preprocessor according to the
260   // current language configuration.
261   if (!LangOpts.Microsoft && !LangOpts.TraditionalCPP)
262     Builder.defineMacro("__STDC__");
263   if (LangOpts.AsmPreprocessor)
264     Builder.defineMacro("__ASSEMBLER__");
265 
266   if (!LangOpts.CPlusPlus) {
267     if (LangOpts.C99)
268       Builder.defineMacro("__STDC_VERSION__", "199901L");
269     else if (!LangOpts.GNUMode && LangOpts.Digraphs)
270       Builder.defineMacro("__STDC_VERSION__", "199409L");
271   }
272 
273   // Standard conforming mode?
274   if (!LangOpts.GNUMode)
275     Builder.defineMacro("__STRICT_ANSI__");
276 
277   if (LangOpts.CPlusPlus0x)
278     Builder.defineMacro("__GXX_EXPERIMENTAL_CXX0X__");
279 
280   if (LangOpts.Freestanding)
281     Builder.defineMacro("__STDC_HOSTED__", "0");
282   else
283     Builder.defineMacro("__STDC_HOSTED__");
284 
285   if (LangOpts.ObjC1) {
286     Builder.defineMacro("__OBJC__");
287     if (LangOpts.ObjCNonFragileABI) {
288       Builder.defineMacro("__OBJC2__");
289       Builder.defineMacro("OBJC_ZEROCOST_EXCEPTIONS");
290     }
291 
292     if (LangOpts.getGCMode() != LangOptions::NonGC)
293       Builder.defineMacro("__OBJC_GC__");
294 
295     if (LangOpts.NeXTRuntime)
296       Builder.defineMacro("__NEXT_RUNTIME__");
297   }
298 
299   // darwin_constant_cfstrings controls this. This is also dependent
300   // on other things like the runtime I believe.  This is set even for C code.
301   Builder.defineMacro("__CONSTANT_CFSTRINGS__");
302 
303   if (LangOpts.ObjC2)
304     Builder.defineMacro("OBJC_NEW_PROPERTIES");
305 
306   if (LangOpts.PascalStrings)
307     Builder.defineMacro("__PASCAL_STRINGS__");
308 
309   if (LangOpts.Blocks) {
310     Builder.defineMacro("__block", "__attribute__((__blocks__(byref)))");
311     Builder.defineMacro("__BLOCKS__");
312   }
313 
314   if (LangOpts.Exceptions)
315     Builder.defineMacro("__EXCEPTIONS");
316   if (LangOpts.RTTI)
317     Builder.defineMacro("__GXX_RTTI");
318   if (LangOpts.SjLjExceptions)
319     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
320 
321   if (LangOpts.CPlusPlus) {
322     if (LangOpts.Deprecated)
323       Builder.defineMacro("__DEPRECATED");
324     Builder.defineMacro("__GNUG__", "4");
325     Builder.defineMacro("__GXX_WEAK__");
326     if (LangOpts.GNUMode)
327       Builder.defineMacro("__cplusplus");
328     else
329       // C++ [cpp.predefined]p1:
330       //   The name_ _cplusplusis defined to the value 199711L when compiling a
331       //   C++ translation unit.
332       Builder.defineMacro("__cplusplus", "199711L");
333     Builder.defineMacro("__private_extern__", "extern");
334   }
335 
336   if (LangOpts.Microsoft) {
337     // Filter out some microsoft extensions when trying to parse in ms-compat
338     // mode.
339     Builder.defineMacro("__int8", "__INT8_TYPE__");
340     Builder.defineMacro("__int16", "__INT16_TYPE__");
341     Builder.defineMacro("__int32", "__INT32_TYPE__");
342     Builder.defineMacro("__int64", "__INT64_TYPE__");
343     // Both __PRETTY_FUNCTION__ and __FUNCTION__ are GCC extensions, however
344     // VC++ appears to only like __FUNCTION__.
345     Builder.defineMacro("__PRETTY_FUNCTION__", "__FUNCTION__");
346     // Work around some issues with Visual C++ headerws.
347     if (LangOpts.CPlusPlus) {
348       // Since we define wchar_t in C++ mode.
349       Builder.defineMacro("_WCHAR_T_DEFINED");
350       Builder.defineMacro("_NATIVE_WCHAR_T_DEFINED");
351       Builder.append("class type_info;");
352     }
353 
354     if (LangOpts.CPlusPlus0x) {
355       Builder.defineMacro("_HAS_CHAR16_T_LANGUAGE_SUPPORT", "1");
356     }
357   }
358 
359   if (LangOpts.Optimize)
360     Builder.defineMacro("__OPTIMIZE__");
361   if (LangOpts.OptimizeSize)
362     Builder.defineMacro("__OPTIMIZE_SIZE__");
363 
364   // Initialize target-specific preprocessor defines.
365 
366   // Define type sizing macros based on the target properties.
367   assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
368   Builder.defineMacro("__CHAR_BIT__", "8");
369 
370   DefineTypeSize("__SCHAR_MAX__", TI.getCharWidth(), "", true, Builder);
371   DefineTypeSize("__SHRT_MAX__", TargetInfo::SignedShort, TI, Builder);
372   DefineTypeSize("__INT_MAX__", TargetInfo::SignedInt, TI, Builder);
373   DefineTypeSize("__LONG_MAX__", TargetInfo::SignedLong, TI, Builder);
374   DefineTypeSize("__LONG_LONG_MAX__", TargetInfo::SignedLongLong, TI, Builder);
375   DefineTypeSize("__WCHAR_MAX__", TI.getWCharType(), TI, Builder);
376   DefineTypeSize("__INTMAX_MAX__", TI.getIntMaxType(), TI, Builder);
377 
378   DefineTypeSizeof("__SIZEOF_DOUBLE__", TI.getDoubleWidth(), TI, Builder);
379   DefineTypeSizeof("__SIZEOF_FLOAT__", TI.getFloatWidth(), TI, Builder);
380   DefineTypeSizeof("__SIZEOF_INT__", TI.getIntWidth(), TI, Builder);
381   DefineTypeSizeof("__SIZEOF_LONG__", TI.getLongWidth(), TI, Builder);
382   DefineTypeSizeof("__SIZEOF_LONG_DOUBLE__",TI.getLongDoubleWidth(),TI,Builder);
383   DefineTypeSizeof("__SIZEOF_LONG_LONG__", TI.getLongLongWidth(), TI, Builder);
384   DefineTypeSizeof("__SIZEOF_POINTER__", TI.getPointerWidth(0), TI, Builder);
385   DefineTypeSizeof("__SIZEOF_SHORT__", TI.getShortWidth(), TI, Builder);
386   DefineTypeSizeof("__SIZEOF_PTRDIFF_T__",
387                    TI.getTypeWidth(TI.getPtrDiffType(0)), TI, Builder);
388   DefineTypeSizeof("__SIZEOF_SIZE_T__",
389                    TI.getTypeWidth(TI.getSizeType()), TI, Builder);
390   DefineTypeSizeof("__SIZEOF_WCHAR_T__",
391                    TI.getTypeWidth(TI.getWCharType()), TI, Builder);
392   DefineTypeSizeof("__SIZEOF_WINT_T__",
393                    TI.getTypeWidth(TI.getWIntType()), TI, Builder);
394 
395   DefineType("__INTMAX_TYPE__", TI.getIntMaxType(), Builder);
396   DefineType("__UINTMAX_TYPE__", TI.getUIntMaxType(), Builder);
397   DefineTypeWidth("__INTMAX_WIDTH__",  TI.getIntMaxType(), TI, Builder);
398   DefineType("__PTRDIFF_TYPE__", TI.getPtrDiffType(0), Builder);
399   DefineTypeWidth("__PTRDIFF_WIDTH__", TI.getPtrDiffType(0), TI, Builder);
400   DefineType("__INTPTR_TYPE__", TI.getIntPtrType(), Builder);
401   DefineTypeWidth("__INTPTR_WIDTH__", TI.getIntPtrType(), TI, Builder);
402   DefineType("__SIZE_TYPE__", TI.getSizeType(), Builder);
403   DefineTypeWidth("__SIZE_WIDTH__", TI.getSizeType(), TI, Builder);
404   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Builder);
405   DefineTypeWidth("__WCHAR_WIDTH__", TI.getWCharType(), TI, Builder);
406   DefineType("__WINT_TYPE__", TI.getWIntType(), Builder);
407   DefineTypeWidth("__WINT_WIDTH__", TI.getWIntType(), TI, Builder);
408   DefineTypeWidth("__SIG_ATOMIC_WIDTH__", TI.getSigAtomicType(), TI, Builder);
409   DefineType("__CHAR16_TYPE__", TI.getChar16Type(), Builder);
410   DefineType("__CHAR32_TYPE__", TI.getChar32Type(), Builder);
411 
412   DefineFloatMacros(Builder, "FLT", &TI.getFloatFormat());
413   DefineFloatMacros(Builder, "DBL", &TI.getDoubleFormat());
414   DefineFloatMacros(Builder, "LDBL", &TI.getLongDoubleFormat());
415 
416   // Define a __POINTER_WIDTH__ macro for stdint.h.
417   Builder.defineMacro("__POINTER_WIDTH__",
418                       llvm::Twine((int)TI.getPointerWidth(0)));
419 
420   if (!LangOpts.CharIsSigned)
421     Builder.defineMacro("__CHAR_UNSIGNED__");
422 
423   if (!TargetInfo::isTypeSigned(TI.getWIntType()))
424     Builder.defineMacro("__WINT_UNSIGNED__");
425 
426   // Define exact-width integer types for stdint.h
427   Builder.defineMacro("__INT" + llvm::Twine(TI.getCharWidth()) + "_TYPE__",
428                       "char");
429 
430   if (TI.getShortWidth() > TI.getCharWidth())
431     DefineExactWidthIntType(TargetInfo::SignedShort, TI, Builder);
432 
433   if (TI.getIntWidth() > TI.getShortWidth())
434     DefineExactWidthIntType(TargetInfo::SignedInt, TI, Builder);
435 
436   if (TI.getLongWidth() > TI.getIntWidth())
437     DefineExactWidthIntType(TargetInfo::SignedLong, TI, Builder);
438 
439   if (TI.getLongLongWidth() > TI.getLongWidth())
440     DefineExactWidthIntType(TargetInfo::SignedLongLong, TI, Builder);
441 
442   // Add __builtin_va_list typedef.
443   Builder.append(TI.getVAListDeclaration());
444 
445   if (const char *Prefix = TI.getUserLabelPrefix())
446     Builder.defineMacro("__USER_LABEL_PREFIX__", Prefix);
447 
448   // Build configuration options.  FIXME: these should be controlled by
449   // command line options or something.
450   Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
451 
452   if (LangOpts.GNUInline)
453     Builder.defineMacro("__GNUC_GNU_INLINE__");
454   else
455     Builder.defineMacro("__GNUC_STDC_INLINE__");
456 
457   if (LangOpts.NoInline)
458     Builder.defineMacro("__NO_INLINE__");
459 
460   if (unsigned PICLevel = LangOpts.PICLevel) {
461     Builder.defineMacro("__PIC__", llvm::Twine(PICLevel));
462     Builder.defineMacro("__pic__", llvm::Twine(PICLevel));
463   }
464 
465   // Macros to control C99 numerics and <float.h>
466   Builder.defineMacro("__FLT_EVAL_METHOD__", "0");
467   Builder.defineMacro("__FLT_RADIX__", "2");
468   int Dig = PickFP(&TI.getLongDoubleFormat(), -1/*FIXME*/, 17, 21, 33, 36);
469   Builder.defineMacro("__DECIMAL_DIG__", llvm::Twine(Dig));
470 
471   if (LangOpts.getStackProtectorMode() == LangOptions::SSPOn)
472     Builder.defineMacro("__SSP__");
473   else if (LangOpts.getStackProtectorMode() == LangOptions::SSPReq)
474     Builder.defineMacro("__SSP_ALL__", "2");
475 
476   if (FEOpts.ProgramAction == frontend::RewriteObjC)
477     Builder.defineMacro("__weak", "__attribute__((objc_gc(weak)))");
478 
479   // Define a macro that exists only when using the static analyzer.
480   if (FEOpts.ProgramAction == frontend::RunAnalysis)
481     Builder.defineMacro("__clang_analyzer__");
482 
483   if (LangOpts.FastRelaxedMath)
484     Builder.defineMacro("__FAST_RELAXED_MATH__");
485 
486   // Get other target #defines.
487   TI.getTargetDefines(LangOpts, Builder);
488 }
489 
490 // Initialize the remapping of files to alternative contents, e.g.,
491 // those specified through other files.
492 static void InitializeFileRemapping(Diagnostic &Diags,
493                                     SourceManager &SourceMgr,
494                                     FileManager &FileMgr,
495                                     const PreprocessorOptions &InitOpts) {
496   // Remap files in the source manager (with buffers).
497   for (PreprocessorOptions::const_remapped_file_buffer_iterator
498          Remap = InitOpts.remapped_file_buffer_begin(),
499          RemapEnd = InitOpts.remapped_file_buffer_end();
500        Remap != RemapEnd;
501        ++Remap) {
502     // Create the file entry for the file that we're mapping from.
503     const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
504                                                 Remap->second->getBufferSize(),
505                                                        0);
506     if (!FromFile) {
507       Diags.Report(diag::err_fe_remap_missing_from_file)
508         << Remap->first;
509       if (!InitOpts.RetainRemappedFileBuffers)
510         delete Remap->second;
511       continue;
512     }
513 
514     // Override the contents of the "from" file with the contents of
515     // the "to" file.
516     SourceMgr.overrideFileContents(FromFile, Remap->second,
517                                    InitOpts.RetainRemappedFileBuffers);
518   }
519 
520   // Remap files in the source manager (with other files).
521   for (PreprocessorOptions::const_remapped_file_iterator
522          Remap = InitOpts.remapped_file_begin(),
523          RemapEnd = InitOpts.remapped_file_end();
524        Remap != RemapEnd;
525        ++Remap) {
526     // Find the file that we're mapping to.
527     const FileEntry *ToFile = FileMgr.getFile(Remap->second);
528     if (!ToFile) {
529       Diags.Report(diag::err_fe_remap_missing_to_file)
530       << Remap->first << Remap->second;
531       continue;
532     }
533 
534     // Create the file entry for the file that we're mapping from.
535     const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
536                                                        ToFile->getSize(), 0);
537     if (!FromFile) {
538       Diags.Report(diag::err_fe_remap_missing_from_file)
539       << Remap->first;
540       continue;
541     }
542 
543     // Override the contents of the "from" file with the contents of
544     // the "to" file.
545     SourceMgr.overrideFileContents(FromFile, ToFile);
546   }
547 
548   SourceMgr.setOverridenFilesKeepOriginalName(
549                                         InitOpts.RemappedFilesKeepOriginalName);
550 }
551 
552 /// InitializePreprocessor - Initialize the preprocessor getting it and the
553 /// environment ready to process a single file. This returns true on error.
554 ///
555 void clang::InitializePreprocessor(Preprocessor &PP,
556                                    const PreprocessorOptions &InitOpts,
557                                    const HeaderSearchOptions &HSOpts,
558                                    const FrontendOptions &FEOpts) {
559   std::string PredefineBuffer;
560   PredefineBuffer.reserve(4080);
561   llvm::raw_string_ostream Predefines(PredefineBuffer);
562   MacroBuilder Builder(Predefines);
563 
564   InitializeFileRemapping(PP.getDiagnostics(), PP.getSourceManager(),
565                           PP.getFileManager(), InitOpts);
566 
567   // Emit line markers for various builtin sections of the file.  We don't do
568   // this in asm preprocessor mode, because "# 4" is not a line marker directive
569   // in this mode.
570   if (!PP.getLangOptions().AsmPreprocessor)
571     Builder.append("# 1 \"<built-in>\" 3");
572 
573   // Install things like __POWERPC__, __GNUC__, etc into the macro table.
574   if (InitOpts.UsePredefines)
575     InitializePredefinedMacros(PP.getTargetInfo(), PP.getLangOptions(),
576                                FEOpts, Builder);
577 
578   // Add on the predefines from the driver.  Wrap in a #line directive to report
579   // that they come from the command line.
580   if (!PP.getLangOptions().AsmPreprocessor)
581     Builder.append("# 1 \"<command line>\" 1");
582 
583   // Process #define's and #undef's in the order they are given.
584   for (unsigned i = 0, e = InitOpts.Macros.size(); i != e; ++i) {
585     if (InitOpts.Macros[i].second)  // isUndef
586       Builder.undefineMacro(InitOpts.Macros[i].first);
587     else
588       DefineBuiltinMacro(Builder, InitOpts.Macros[i].first,
589                          PP.getDiagnostics());
590   }
591 
592   // If -imacros are specified, include them now.  These are processed before
593   // any -include directives.
594   for (unsigned i = 0, e = InitOpts.MacroIncludes.size(); i != e; ++i)
595     AddImplicitIncludeMacros(Builder, InitOpts.MacroIncludes[i],
596                              PP.getFileManager());
597 
598   // Process -include directives.
599   for (unsigned i = 0, e = InitOpts.Includes.size(); i != e; ++i) {
600     const std::string &Path = InitOpts.Includes[i];
601     if (Path == InitOpts.ImplicitPTHInclude)
602       AddImplicitIncludePTH(Builder, PP, Path);
603     else
604       AddImplicitInclude(Builder, Path, PP.getFileManager());
605   }
606 
607   // Exit the command line and go back to <built-in> (2 is LC_LEAVE).
608   if (!PP.getLangOptions().AsmPreprocessor)
609     Builder.append("# 1 \"<built-in>\" 2");
610 
611   // Instruct the preprocessor to skip the preamble.
612   PP.setSkipMainFilePreamble(InitOpts.PrecompiledPreambleBytes.first,
613                              InitOpts.PrecompiledPreambleBytes.second);
614 
615   // Copy PredefinedBuffer into the Preprocessor.
616   PP.setPredefines(Predefines.str());
617 
618   // Initialize the header search object.
619   ApplyHeaderSearchOptions(PP.getHeaderSearchInfo(), HSOpts,
620                            PP.getLangOptions(),
621                            PP.getTargetInfo().getTriple());
622 }
623