xref: /llvm-project/clang/lib/Frontend/InitPreprocessor.cpp (revision a6820332b35369f1a0d9afe1fe80532601296d49)
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 InitializeStandardPredefinedMacros(const TargetInfo &TI,
225                                                const LangOptions &LangOpts,
226                                                const FrontendOptions &FEOpts,
227                                                MacroBuilder &Builder) {
228   if (!LangOpts.Microsoft && !LangOpts.TraditionalCPP)
229     Builder.defineMacro("__STDC__");
230   if (LangOpts.Freestanding)
231     Builder.defineMacro("__STDC_HOSTED__", "0");
232   else
233     Builder.defineMacro("__STDC_HOSTED__");
234 
235   if (!LangOpts.CPlusPlus) {
236     if (LangOpts.C99)
237       Builder.defineMacro("__STDC_VERSION__", "199901L");
238     else if (!LangOpts.GNUMode && LangOpts.Digraphs)
239       Builder.defineMacro("__STDC_VERSION__", "199409L");
240   } else {
241     if (LangOpts.GNUMode)
242       Builder.defineMacro("__cplusplus");
243     else
244       // C++ [cpp.predefined]p1:
245       //   The name_ _cplusplus is defined to the value 199711L when compiling a
246       //   C++ translation unit.
247       Builder.defineMacro("__cplusplus", "199711L");
248   }
249 
250   // Not "standard" per se, but available even with the -undef flag.
251   if (LangOpts.AsmPreprocessor)
252     Builder.defineMacro("__ASSEMBLER__");
253 }
254 
255 static void InitializePredefinedMacros(const TargetInfo &TI,
256                                        const LangOptions &LangOpts,
257                                        const FrontendOptions &FEOpts,
258                                        MacroBuilder &Builder) {
259   // Compiler version introspection macros.
260   Builder.defineMacro("__llvm__");  // LLVM Backend
261   Builder.defineMacro("__clang__"); // Clang Frontend
262 #define TOSTR2(X) #X
263 #define TOSTR(X) TOSTR2(X)
264   Builder.defineMacro("__clang_major__", TOSTR(CLANG_VERSION_MAJOR));
265   Builder.defineMacro("__clang_minor__", TOSTR(CLANG_VERSION_MINOR));
266 #ifdef CLANG_VERSION_PATCHLEVEL
267   Builder.defineMacro("__clang_patchlevel__", TOSTR(CLANG_VERSION_PATCHLEVEL));
268 #else
269   Builder.defineMacro("__clang_patchlevel__", "0");
270 #endif
271   Builder.defineMacro("__clang_version__",
272                       "\"" CLANG_VERSION_STRING " ("
273                       + getClangFullRepositoryVersion() + ")\"");
274 #undef TOSTR
275 #undef TOSTR2
276   // Currently claim to be compatible with GCC 4.2.1-5621.
277   Builder.defineMacro("__GNUC_MINOR__", "2");
278   Builder.defineMacro("__GNUC_PATCHLEVEL__", "1");
279   Builder.defineMacro("__GNUC__", "4");
280   Builder.defineMacro("__GXX_ABI_VERSION", "1002");
281 
282   // As sad as it is, enough software depends on the __VERSION__ for version
283   // checks that it is necessary to report 4.2.1 (the base GCC version we claim
284   // compatibility with) first.
285   Builder.defineMacro("__VERSION__", "\"4.2.1 Compatible " +
286                       llvm::Twine(getClangFullCPPVersion()) + "\"");
287 
288   // Initialize language-specific preprocessor defines.
289 
290   // Standard conforming mode?
291   if (!LangOpts.GNUMode)
292     Builder.defineMacro("__STRICT_ANSI__");
293 
294   if (LangOpts.CPlusPlus0x)
295     Builder.defineMacro("__GXX_EXPERIMENTAL_CXX0X__");
296 
297   if (LangOpts.ObjC1) {
298     Builder.defineMacro("__OBJC__");
299     if (LangOpts.ObjCNonFragileABI) {
300       Builder.defineMacro("__OBJC2__");
301       Builder.defineMacro("OBJC_ZEROCOST_EXCEPTIONS");
302     }
303 
304     if (LangOpts.getGCMode() != LangOptions::NonGC)
305       Builder.defineMacro("__OBJC_GC__");
306 
307     if (LangOpts.NeXTRuntime)
308       Builder.defineMacro("__NEXT_RUNTIME__");
309   }
310 
311   // darwin_constant_cfstrings controls this. This is also dependent
312   // on other things like the runtime I believe.  This is set even for C code.
313   Builder.defineMacro("__CONSTANT_CFSTRINGS__");
314 
315   if (LangOpts.ObjC2)
316     Builder.defineMacro("OBJC_NEW_PROPERTIES");
317 
318   if (LangOpts.PascalStrings)
319     Builder.defineMacro("__PASCAL_STRINGS__");
320 
321   if (LangOpts.Blocks) {
322     Builder.defineMacro("__block", "__attribute__((__blocks__(byref)))");
323     Builder.defineMacro("__BLOCKS__");
324   }
325 
326   if (LangOpts.Exceptions)
327     Builder.defineMacro("__EXCEPTIONS");
328   if (LangOpts.RTTI)
329     Builder.defineMacro("__GXX_RTTI");
330   if (LangOpts.SjLjExceptions)
331     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
332 
333   if (LangOpts.Deprecated)
334     Builder.defineMacro("__DEPRECATED");
335 
336   if (LangOpts.CPlusPlus) {
337     Builder.defineMacro("__GNUG__", "4");
338     Builder.defineMacro("__GXX_WEAK__");
339     Builder.defineMacro("__private_extern__", "extern");
340   }
341 
342   if (LangOpts.Microsoft) {
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       // FIXME: Support Microsoft's __identifier extension in the lexer.
352       Builder.append("#define __identifier(x) x");
353       Builder.append("class type_info;");
354     }
355 
356     if (LangOpts.CPlusPlus0x) {
357       Builder.defineMacro("_HAS_CHAR16_T_LANGUAGE_SUPPORT", "1");
358     }
359   }
360 
361   if (LangOpts.Optimize)
362     Builder.defineMacro("__OPTIMIZE__");
363   if (LangOpts.OptimizeSize)
364     Builder.defineMacro("__OPTIMIZE_SIZE__");
365 
366   // Initialize target-specific preprocessor defines.
367 
368   // Define type sizing macros based on the target properties.
369   assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
370   Builder.defineMacro("__CHAR_BIT__", "8");
371 
372   DefineTypeSize("__SCHAR_MAX__", TI.getCharWidth(), "", true, Builder);
373   DefineTypeSize("__SHRT_MAX__", TargetInfo::SignedShort, TI, Builder);
374   DefineTypeSize("__INT_MAX__", TargetInfo::SignedInt, TI, Builder);
375   DefineTypeSize("__LONG_MAX__", TargetInfo::SignedLong, TI, Builder);
376   DefineTypeSize("__LONG_LONG_MAX__", TargetInfo::SignedLongLong, TI, Builder);
377   DefineTypeSize("__WCHAR_MAX__", TI.getWCharType(), TI, Builder);
378   DefineTypeSize("__INTMAX_MAX__", TI.getIntMaxType(), TI, Builder);
379 
380   DefineTypeSizeof("__SIZEOF_DOUBLE__", TI.getDoubleWidth(), TI, Builder);
381   DefineTypeSizeof("__SIZEOF_FLOAT__", TI.getFloatWidth(), TI, Builder);
382   DefineTypeSizeof("__SIZEOF_INT__", TI.getIntWidth(), TI, Builder);
383   DefineTypeSizeof("__SIZEOF_LONG__", TI.getLongWidth(), TI, Builder);
384   DefineTypeSizeof("__SIZEOF_LONG_DOUBLE__",TI.getLongDoubleWidth(),TI,Builder);
385   DefineTypeSizeof("__SIZEOF_LONG_LONG__", TI.getLongLongWidth(), TI, Builder);
386   DefineTypeSizeof("__SIZEOF_POINTER__", TI.getPointerWidth(0), TI, Builder);
387   DefineTypeSizeof("__SIZEOF_SHORT__", TI.getShortWidth(), TI, Builder);
388   DefineTypeSizeof("__SIZEOF_PTRDIFF_T__",
389                    TI.getTypeWidth(TI.getPtrDiffType(0)), TI, Builder);
390   DefineTypeSizeof("__SIZEOF_SIZE_T__",
391                    TI.getTypeWidth(TI.getSizeType()), TI, Builder);
392   DefineTypeSizeof("__SIZEOF_WCHAR_T__",
393                    TI.getTypeWidth(TI.getWCharType()), TI, Builder);
394   DefineTypeSizeof("__SIZEOF_WINT_T__",
395                    TI.getTypeWidth(TI.getWIntType()), TI, Builder);
396 
397   DefineType("__INTMAX_TYPE__", TI.getIntMaxType(), Builder);
398   DefineType("__UINTMAX_TYPE__", TI.getUIntMaxType(), Builder);
399   DefineTypeWidth("__INTMAX_WIDTH__",  TI.getIntMaxType(), TI, Builder);
400   DefineType("__PTRDIFF_TYPE__", TI.getPtrDiffType(0), Builder);
401   DefineTypeWidth("__PTRDIFF_WIDTH__", TI.getPtrDiffType(0), TI, Builder);
402   DefineType("__INTPTR_TYPE__", TI.getIntPtrType(), Builder);
403   DefineTypeWidth("__INTPTR_WIDTH__", TI.getIntPtrType(), TI, Builder);
404   DefineType("__SIZE_TYPE__", TI.getSizeType(), Builder);
405   DefineTypeWidth("__SIZE_WIDTH__", TI.getSizeType(), TI, Builder);
406   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Builder);
407   DefineTypeWidth("__WCHAR_WIDTH__", TI.getWCharType(), TI, Builder);
408   DefineType("__WINT_TYPE__", TI.getWIntType(), Builder);
409   DefineTypeWidth("__WINT_WIDTH__", TI.getWIntType(), TI, Builder);
410   DefineTypeWidth("__SIG_ATOMIC_WIDTH__", TI.getSigAtomicType(), TI, Builder);
411   DefineType("__CHAR16_TYPE__", TI.getChar16Type(), Builder);
412   DefineType("__CHAR32_TYPE__", TI.getChar32Type(), Builder);
413 
414   DefineFloatMacros(Builder, "FLT", &TI.getFloatFormat());
415   DefineFloatMacros(Builder, "DBL", &TI.getDoubleFormat());
416   DefineFloatMacros(Builder, "LDBL", &TI.getLongDoubleFormat());
417 
418   // Define a __POINTER_WIDTH__ macro for stdint.h.
419   Builder.defineMacro("__POINTER_WIDTH__",
420                       llvm::Twine((int)TI.getPointerWidth(0)));
421 
422   if (!LangOpts.CharIsSigned)
423     Builder.defineMacro("__CHAR_UNSIGNED__");
424 
425   if (!TargetInfo::isTypeSigned(TI.getWIntType()))
426     Builder.defineMacro("__WINT_UNSIGNED__");
427 
428   // Define exact-width integer types for stdint.h
429   Builder.defineMacro("__INT" + llvm::Twine(TI.getCharWidth()) + "_TYPE__",
430                       "char");
431 
432   if (TI.getShortWidth() > TI.getCharWidth())
433     DefineExactWidthIntType(TargetInfo::SignedShort, TI, Builder);
434 
435   if (TI.getIntWidth() > TI.getShortWidth())
436     DefineExactWidthIntType(TargetInfo::SignedInt, TI, Builder);
437 
438   if (TI.getLongWidth() > TI.getIntWidth())
439     DefineExactWidthIntType(TargetInfo::SignedLong, TI, Builder);
440 
441   if (TI.getLongLongWidth() > TI.getLongWidth())
442     DefineExactWidthIntType(TargetInfo::SignedLongLong, TI, Builder);
443 
444   // Add __builtin_va_list typedef.
445   Builder.append(TI.getVAListDeclaration());
446 
447   if (const char *Prefix = TI.getUserLabelPrefix())
448     Builder.defineMacro("__USER_LABEL_PREFIX__", Prefix);
449 
450   // Build configuration options.  FIXME: these should be controlled by
451   // command line options or something.
452   Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
453 
454   if (LangOpts.GNUInline)
455     Builder.defineMacro("__GNUC_GNU_INLINE__");
456   else
457     Builder.defineMacro("__GNUC_STDC_INLINE__");
458 
459   if (LangOpts.NoInline)
460     Builder.defineMacro("__NO_INLINE__");
461 
462   if (unsigned PICLevel = LangOpts.PICLevel) {
463     Builder.defineMacro("__PIC__", llvm::Twine(PICLevel));
464     Builder.defineMacro("__pic__", llvm::Twine(PICLevel));
465   }
466 
467   // Macros to control C99 numerics and <float.h>
468   Builder.defineMacro("__FLT_EVAL_METHOD__", "0");
469   Builder.defineMacro("__FLT_RADIX__", "2");
470   int Dig = PickFP(&TI.getLongDoubleFormat(), -1/*FIXME*/, 17, 21, 33, 36);
471   Builder.defineMacro("__DECIMAL_DIG__", llvm::Twine(Dig));
472 
473   if (LangOpts.getStackProtectorMode() == LangOptions::SSPOn)
474     Builder.defineMacro("__SSP__");
475   else if (LangOpts.getStackProtectorMode() == LangOptions::SSPReq)
476     Builder.defineMacro("__SSP_ALL__", "2");
477 
478   if (FEOpts.ProgramAction == frontend::RewriteObjC)
479     Builder.defineMacro("__weak", "__attribute__((objc_gc(weak)))");
480 
481   // Define a macro that exists only when using the static analyzer.
482   if (FEOpts.ProgramAction == frontend::RunAnalysis)
483     Builder.defineMacro("__clang_analyzer__");
484 
485   if (LangOpts.FastRelaxedMath)
486     Builder.defineMacro("__FAST_RELAXED_MATH__");
487 
488   // Get other target #defines.
489   TI.getTargetDefines(LangOpts, Builder);
490 }
491 
492 // Initialize the remapping of files to alternative contents, e.g.,
493 // those specified through other files.
494 static void InitializeFileRemapping(Diagnostic &Diags,
495                                     SourceManager &SourceMgr,
496                                     FileManager &FileMgr,
497                                     const PreprocessorOptions &InitOpts) {
498   // Remap files in the source manager (with buffers).
499   for (PreprocessorOptions::const_remapped_file_buffer_iterator
500          Remap = InitOpts.remapped_file_buffer_begin(),
501          RemapEnd = InitOpts.remapped_file_buffer_end();
502        Remap != RemapEnd;
503        ++Remap) {
504     // Create the file entry for the file that we're mapping from.
505     const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
506                                                 Remap->second->getBufferSize(),
507                                                        0);
508     if (!FromFile) {
509       Diags.Report(diag::err_fe_remap_missing_from_file)
510         << Remap->first;
511       if (!InitOpts.RetainRemappedFileBuffers)
512         delete Remap->second;
513       continue;
514     }
515 
516     // Override the contents of the "from" file with the contents of
517     // the "to" file.
518     SourceMgr.overrideFileContents(FromFile, Remap->second,
519                                    InitOpts.RetainRemappedFileBuffers);
520   }
521 
522   // Remap files in the source manager (with other files).
523   for (PreprocessorOptions::const_remapped_file_iterator
524          Remap = InitOpts.remapped_file_begin(),
525          RemapEnd = InitOpts.remapped_file_end();
526        Remap != RemapEnd;
527        ++Remap) {
528     // Find the file that we're mapping to.
529     const FileEntry *ToFile = FileMgr.getFile(Remap->second);
530     if (!ToFile) {
531       Diags.Report(diag::err_fe_remap_missing_to_file)
532       << Remap->first << Remap->second;
533       continue;
534     }
535 
536     // Create the file entry for the file that we're mapping from.
537     const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
538                                                        ToFile->getSize(), 0);
539     if (!FromFile) {
540       Diags.Report(diag::err_fe_remap_missing_from_file)
541       << Remap->first;
542       continue;
543     }
544 
545     // Override the contents of the "from" file with the contents of
546     // the "to" file.
547     SourceMgr.overrideFileContents(FromFile, ToFile);
548   }
549 
550   SourceMgr.setOverridenFilesKeepOriginalName(
551                                         InitOpts.RemappedFilesKeepOriginalName);
552 }
553 
554 /// InitializePreprocessor - Initialize the preprocessor getting it and the
555 /// environment ready to process a single file. This returns true on error.
556 ///
557 void clang::InitializePreprocessor(Preprocessor &PP,
558                                    const PreprocessorOptions &InitOpts,
559                                    const HeaderSearchOptions &HSOpts,
560                                    const FrontendOptions &FEOpts) {
561   std::string PredefineBuffer;
562   PredefineBuffer.reserve(4080);
563   llvm::raw_string_ostream Predefines(PredefineBuffer);
564   MacroBuilder Builder(Predefines);
565 
566   InitializeFileRemapping(PP.getDiagnostics(), PP.getSourceManager(),
567                           PP.getFileManager(), InitOpts);
568 
569   // Emit line markers for various builtin sections of the file.  We don't do
570   // this in asm preprocessor mode, because "# 4" is not a line marker directive
571   // in this mode.
572   if (!PP.getLangOptions().AsmPreprocessor)
573     Builder.append("# 1 \"<built-in>\" 3");
574 
575   // Install things like __POWERPC__, __GNUC__, etc into the macro table.
576   if (InitOpts.UsePredefines)
577     InitializePredefinedMacros(PP.getTargetInfo(), PP.getLangOptions(),
578                                FEOpts, Builder);
579 
580   // Even with predefines off, some macros are still predefined.
581   // These should all be defined in the preprocessor according to the
582   // current language configuration.
583   InitializeStandardPredefinedMacros(PP.getTargetInfo(), PP.getLangOptions(),
584                                      FEOpts, Builder);
585 
586   // Add on the predefines from the driver.  Wrap in a #line directive to report
587   // that they come from the command line.
588   if (!PP.getLangOptions().AsmPreprocessor)
589     Builder.append("# 1 \"<command line>\" 1");
590 
591   // Process #define's and #undef's in the order they are given.
592   for (unsigned i = 0, e = InitOpts.Macros.size(); i != e; ++i) {
593     if (InitOpts.Macros[i].second)  // isUndef
594       Builder.undefineMacro(InitOpts.Macros[i].first);
595     else
596       DefineBuiltinMacro(Builder, InitOpts.Macros[i].first,
597                          PP.getDiagnostics());
598   }
599 
600   // If -imacros are specified, include them now.  These are processed before
601   // any -include directives.
602   for (unsigned i = 0, e = InitOpts.MacroIncludes.size(); i != e; ++i)
603     AddImplicitIncludeMacros(Builder, InitOpts.MacroIncludes[i],
604                              PP.getFileManager());
605 
606   // Process -include directives.
607   for (unsigned i = 0, e = InitOpts.Includes.size(); i != e; ++i) {
608     const std::string &Path = InitOpts.Includes[i];
609     if (Path == InitOpts.ImplicitPTHInclude)
610       AddImplicitIncludePTH(Builder, PP, Path);
611     else
612       AddImplicitInclude(Builder, Path, PP.getFileManager());
613   }
614 
615   // Exit the command line and go back to <built-in> (2 is LC_LEAVE).
616   if (!PP.getLangOptions().AsmPreprocessor)
617     Builder.append("# 1 \"<built-in>\" 2");
618 
619   // Instruct the preprocessor to skip the preamble.
620   PP.setSkipMainFilePreamble(InitOpts.PrecompiledPreambleBytes.first,
621                              InitOpts.PrecompiledPreambleBytes.second);
622 
623   // Copy PredefinedBuffer into the Preprocessor.
624   PP.setPredefines(Predefines.str());
625 
626   // Initialize the header search object.
627   ApplyHeaderSearchOptions(PP.getHeaderSearchInfo(), HSOpts,
628                            PP.getLangOptions(),
629                            PP.getTargetInfo().getTriple());
630 }
631