xref: /llvm-project/clang/lib/Frontend/InitPreprocessor.cpp (revision 2b1bbecb6b1651de61d258181922d3fab3b28e18)
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/MemoryBuffer.h"
26 #include "llvm/System/Path.h"
27 using namespace clang;
28 
29 // Append a #define line to Buf for Macro.  Macro should be of the form XXX,
30 // in which case we emit "#define XXX 1" or "XXX=Y z W" in which case we emit
31 // "#define XXX Y z W".  To get a #define with no value, use "XXX=".
32 static void DefineBuiltinMacro(MacroBuilder &Builder, llvm::StringRef Macro,
33                                Diagnostic &Diags) {
34   std::pair<llvm::StringRef, llvm::StringRef> MacroPair = Macro.split('=');
35   llvm::StringRef MacroName = MacroPair.first;
36   llvm::StringRef MacroBody = MacroPair.second;
37   if (MacroName.size() != Macro.size()) {
38     // Per GCC -D semantics, the macro ends at \n if it exists.
39     llvm::StringRef::size_type End = MacroBody.find_first_of("\n\r");
40     if (End != llvm::StringRef::npos)
41       Diags.Report(diag::warn_fe_macro_contains_embedded_newline)
42         << MacroName;
43     Builder.defineMacro(MacroName, MacroBody.substr(0, End));
44   } else {
45     // Push "macroname 1".
46     Builder.defineMacro(Macro);
47   }
48 }
49 
50 std::string clang::NormalizeDashIncludePath(llvm::StringRef File) {
51   // Implicit include paths should be resolved relative to the current
52   // working directory first, and then use the regular header search
53   // mechanism. The proper way to handle this is to have the
54   // predefines buffer located at the current working directory, but
55   // it has not file entry. For now, workaround this by using an
56   // absolute path if we find the file here, and otherwise letting
57   // header search handle it.
58   llvm::sys::Path Path(File);
59   Path.makeAbsolute();
60   if (!Path.exists())
61     Path = File;
62 
63   return Lexer::Stringify(Path.str());
64 }
65 
66 /// AddImplicitInclude - Add an implicit #include of the specified file to the
67 /// predefines buffer.
68 static void AddImplicitInclude(MacroBuilder &Builder, llvm::StringRef File) {
69   Builder.append("#include \"" +
70                  llvm::Twine(NormalizeDashIncludePath(File)) + "\"");
71 }
72 
73 static void AddImplicitIncludeMacros(MacroBuilder &Builder,
74                                      llvm::StringRef File) {
75   Builder.append("#__include_macros \"" +
76                  llvm::Twine(NormalizeDashIncludePath(File)) + "\"");
77   // Marker token to stop the __include_macros fetch loop.
78   Builder.append("##"); // ##?
79 }
80 
81 /// AddImplicitIncludePTH - Add an implicit #include using the original file
82 ///  used to generate a PTH cache.
83 static void AddImplicitIncludePTH(MacroBuilder &Builder, Preprocessor &PP,
84                                   llvm::StringRef ImplicitIncludePTH) {
85   PTHManager *P = PP.getPTHManager();
86   // Null check 'P' in the corner case where it couldn't be created.
87   const char *OriginalFile = P ? P->getOriginalSourceFile() : 0;
88 
89   if (!OriginalFile) {
90     PP.getDiagnostics().Report(diag::err_fe_pth_file_has_no_source_header)
91       << ImplicitIncludePTH;
92     return;
93   }
94 
95   AddImplicitInclude(Builder, OriginalFile);
96 }
97 
98 /// PickFP - This is used to pick a value based on the FP semantics of the
99 /// specified FP model.
100 template <typename T>
101 static T PickFP(const llvm::fltSemantics *Sem, T IEEESingleVal,
102                 T IEEEDoubleVal, T X87DoubleExtendedVal, T PPCDoubleDoubleVal,
103                 T IEEEQuadVal) {
104   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEsingle)
105     return IEEESingleVal;
106   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEdouble)
107     return IEEEDoubleVal;
108   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::x87DoubleExtended)
109     return X87DoubleExtendedVal;
110   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::PPCDoubleDouble)
111     return PPCDoubleDoubleVal;
112   assert(Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEquad);
113   return IEEEQuadVal;
114 }
115 
116 static void DefineFloatMacros(MacroBuilder &Builder, llvm::StringRef Prefix,
117                               const llvm::fltSemantics *Sem) {
118   const char *DenormMin, *Epsilon, *Max, *Min;
119   DenormMin = PickFP(Sem, "1.40129846e-45F", "4.9406564584124654e-324",
120                      "3.64519953188247460253e-4951L",
121                      "4.94065645841246544176568792868221e-324L",
122                      "6.47517511943802511092443895822764655e-4966L");
123   int Digits = PickFP(Sem, 6, 15, 18, 31, 33);
124   Epsilon = PickFP(Sem, "1.19209290e-7F", "2.2204460492503131e-16",
125                    "1.08420217248550443401e-19L",
126                    "4.94065645841246544176568792868221e-324L",
127                    "1.92592994438723585305597794258492732e-34L");
128   int MantissaDigits = PickFP(Sem, 24, 53, 64, 106, 113);
129   int Min10Exp = PickFP(Sem, -37, -307, -4931, -291, -4931);
130   int Max10Exp = PickFP(Sem, 38, 308, 4932, 308, 4932);
131   int MinExp = PickFP(Sem, -125, -1021, -16381, -968, -16381);
132   int MaxExp = PickFP(Sem, 128, 1024, 16384, 1024, 16384);
133   Min = PickFP(Sem, "1.17549435e-38F", "2.2250738585072014e-308",
134                "3.36210314311209350626e-4932L",
135                "2.00416836000897277799610805135016e-292L",
136                "3.36210314311209350626267781732175260e-4932L");
137   Max = PickFP(Sem, "3.40282347e+38F", "1.7976931348623157e+308",
138                "1.18973149535723176502e+4932L",
139                "1.79769313486231580793728971405301e+308L",
140                "1.18973149535723176508575932662800702e+4932L");
141 
142   llvm::SmallString<32> DefPrefix;
143   DefPrefix = "__";
144   DefPrefix += Prefix;
145   DefPrefix += "_";
146 
147   Builder.defineMacro(DefPrefix + "DENORM_MIN__", DenormMin);
148   Builder.defineMacro(DefPrefix + "HAS_DENORM__");
149   Builder.defineMacro(DefPrefix + "DIG__", llvm::Twine(Digits));
150   Builder.defineMacro(DefPrefix + "EPSILON__", llvm::Twine(Epsilon));
151   Builder.defineMacro(DefPrefix + "HAS_INFINITY__");
152   Builder.defineMacro(DefPrefix + "HAS_QUIET_NAN__");
153   Builder.defineMacro(DefPrefix + "MANT_DIG__", llvm::Twine(MantissaDigits));
154 
155   Builder.defineMacro(DefPrefix + "MAX_10_EXP__", llvm::Twine(Max10Exp));
156   Builder.defineMacro(DefPrefix + "MAX_EXP__", llvm::Twine(MaxExp));
157   Builder.defineMacro(DefPrefix + "MAX__", llvm::Twine(Max));
158 
159   Builder.defineMacro(DefPrefix + "MIN_10_EXP__","("+llvm::Twine(Min10Exp)+")");
160   Builder.defineMacro(DefPrefix + "MIN_EXP__", "("+llvm::Twine(MinExp)+")");
161   Builder.defineMacro(DefPrefix + "MIN__", llvm::Twine(Min));
162 }
163 
164 
165 /// DefineTypeSize - Emit a macro to the predefines buffer that declares a macro
166 /// named MacroName with the max value for a type with width 'TypeWidth' a
167 /// signedness of 'isSigned' and with a value suffix of 'ValSuffix' (e.g. LL).
168 static void DefineTypeSize(llvm::StringRef MacroName, unsigned TypeWidth,
169                            llvm::StringRef ValSuffix, bool isSigned,
170                            MacroBuilder& Builder) {
171   long long MaxVal;
172   if (isSigned) {
173     assert(TypeWidth != 1);
174     MaxVal = ~0ULL >> (65-TypeWidth);
175   } else
176     MaxVal = ~0ULL >> (64-TypeWidth);
177 
178   Builder.defineMacro(MacroName, llvm::Twine(MaxVal) + ValSuffix);
179 }
180 
181 /// DefineTypeSize - An overloaded helper that uses TargetInfo to determine
182 /// the width, suffix, and signedness of the given type
183 static void DefineTypeSize(llvm::StringRef MacroName, TargetInfo::IntType Ty,
184                            const TargetInfo &TI, MacroBuilder &Builder) {
185   DefineTypeSize(MacroName, TI.getTypeWidth(Ty), TI.getTypeConstantSuffix(Ty),
186                  TI.isTypeSigned(Ty), Builder);
187 }
188 
189 static void DefineType(const llvm::Twine &MacroName, TargetInfo::IntType Ty,
190                        MacroBuilder &Builder) {
191   Builder.defineMacro(MacroName, TargetInfo::getTypeName(Ty));
192 }
193 
194 static void DefineTypeWidth(llvm::StringRef MacroName, TargetInfo::IntType Ty,
195                             const TargetInfo &TI, MacroBuilder &Builder) {
196   Builder.defineMacro(MacroName, llvm::Twine(TI.getTypeWidth(Ty)));
197 }
198 
199 static void DefineTypeSizeof(llvm::StringRef MacroName, unsigned BitWidth,
200                              const TargetInfo &TI, MacroBuilder &Builder) {
201   Builder.defineMacro(MacroName,
202                       llvm::Twine(BitWidth / TI.getCharWidth()));
203 }
204 
205 static void DefineExactWidthIntType(TargetInfo::IntType Ty,
206                                const TargetInfo &TI, MacroBuilder &Builder) {
207   int TypeWidth = TI.getTypeWidth(Ty);
208 
209   // Use the target specified int64 type, when appropriate, so that [u]int64_t
210   // ends up being defined in terms of the correct type.
211   if (TypeWidth == 64)
212     Ty = TI.getInt64Type();
213 
214   DefineType("__INT" + llvm::Twine(TypeWidth) + "_TYPE__", Ty, Builder);
215 
216   llvm::StringRef ConstSuffix(TargetInfo::getTypeConstantSuffix(Ty));
217   if (!ConstSuffix.empty())
218     Builder.defineMacro("__INT" + llvm::Twine(TypeWidth) + "_C_SUFFIX__",
219                         ConstSuffix);
220 }
221 
222 static void InitializePredefinedMacros(const TargetInfo &TI,
223                                        const LangOptions &LangOpts,
224                                        const FrontendOptions &FEOpts,
225                                        MacroBuilder &Builder) {
226   // Compiler version introspection macros.
227   Builder.defineMacro("__llvm__");  // LLVM Backend
228   Builder.defineMacro("__clang__"); // Clang Frontend
229 #define TOSTR2(X) #X
230 #define TOSTR(X) TOSTR2(X)
231   Builder.defineMacro("__clang_major__", TOSTR(CLANG_VERSION_MAJOR));
232   Builder.defineMacro("__clang_minor__", TOSTR(CLANG_VERSION_MINOR));
233 #ifdef CLANG_VERSION_PATCHLEVEL
234   Builder.defineMacro("__clang_patchlevel__", TOSTR(CLANG_VERSION_PATCHLEVEL));
235 #else
236   Builder.defineMacro("__clang_patchlevel__", "0");
237 #endif
238   Builder.defineMacro("__clang_version__",
239                       "\"" CLANG_VERSION_STRING " ("
240                       + getClangFullRepositoryVersion() + ")\"");
241 #undef TOSTR
242 #undef TOSTR2
243   // Currently claim to be compatible with GCC 4.2.1-5621.
244   Builder.defineMacro("__GNUC_MINOR__", "2");
245   Builder.defineMacro("__GNUC_PATCHLEVEL__", "1");
246   Builder.defineMacro("__GNUC__", "4");
247   Builder.defineMacro("__GXX_ABI_VERSION", "1002");
248   Builder.defineMacro("__VERSION__", "\"4.2.1 Compatible Clang Compiler\"");
249 
250   // Initialize language-specific preprocessor defines.
251 
252   // These should all be defined in the preprocessor according to the
253   // current language configuration.
254   if (!LangOpts.Microsoft)
255     Builder.defineMacro("__STDC__");
256   if (LangOpts.AsmPreprocessor)
257     Builder.defineMacro("__ASSEMBLER__");
258 
259   if (!LangOpts.CPlusPlus) {
260     if (LangOpts.C99)
261       Builder.defineMacro("__STDC_VERSION__", "199901L");
262     else if (!LangOpts.GNUMode && LangOpts.Digraphs)
263       Builder.defineMacro("__STDC_VERSION__", "199409L");
264   }
265 
266   // Standard conforming mode?
267   if (!LangOpts.GNUMode)
268     Builder.defineMacro("__STRICT_ANSI__");
269 
270   if (LangOpts.CPlusPlus0x)
271     Builder.defineMacro("__GXX_EXPERIMENTAL_CXX0X__");
272 
273   if (LangOpts.Freestanding)
274     Builder.defineMacro("__STDC_HOSTED__", "0");
275   else
276     Builder.defineMacro("__STDC_HOSTED__");
277 
278   if (LangOpts.ObjC1) {
279     Builder.defineMacro("__OBJC__");
280     if (LangOpts.ObjCNonFragileABI) {
281       Builder.defineMacro("__OBJC2__");
282       Builder.defineMacro("OBJC_ZEROCOST_EXCEPTIONS");
283     }
284 
285     if (LangOpts.getGCMode() != LangOptions::NonGC)
286       Builder.defineMacro("__OBJC_GC__");
287 
288     if (LangOpts.NeXTRuntime)
289       Builder.defineMacro("__NEXT_RUNTIME__");
290   }
291 
292   // darwin_constant_cfstrings controls this. This is also dependent
293   // on other things like the runtime I believe.  This is set even for C code.
294   Builder.defineMacro("__CONSTANT_CFSTRINGS__");
295 
296   if (LangOpts.ObjC2)
297     Builder.defineMacro("OBJC_NEW_PROPERTIES");
298 
299   if (LangOpts.PascalStrings)
300     Builder.defineMacro("__PASCAL_STRINGS__");
301 
302   if (LangOpts.Blocks) {
303     Builder.defineMacro("__block", "__attribute__((__blocks__(byref)))");
304     Builder.defineMacro("__BLOCKS__");
305   }
306 
307   if (LangOpts.Exceptions)
308     Builder.defineMacro("__EXCEPTIONS");
309   if (LangOpts.RTTI)
310     Builder.defineMacro("__GXX_RTTI");
311   if (LangOpts.SjLjExceptions)
312     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
313 
314   if (LangOpts.CPlusPlus) {
315     Builder.defineMacro("__DEPRECATED");
316     Builder.defineMacro("__GNUG__", "4");
317     Builder.defineMacro("__GXX_WEAK__");
318     if (LangOpts.GNUMode)
319       Builder.defineMacro("__cplusplus");
320     else
321       // C++ [cpp.predefined]p1:
322       //   The name_ _cplusplusis defined to the value 199711L when compiling a
323       //   C++ translation unit.
324       Builder.defineMacro("__cplusplus", "199711L");
325     Builder.defineMacro("__private_extern__", "extern");
326   }
327 
328   if (LangOpts.Microsoft) {
329     // Filter out some microsoft extensions when trying to parse in ms-compat
330     // mode.
331     Builder.defineMacro("__int8", "__INT8_TYPE__");
332     Builder.defineMacro("__int16", "__INT16_TYPE__");
333     Builder.defineMacro("__int32", "__INT32_TYPE__");
334     Builder.defineMacro("__int64", "__INT64_TYPE__");
335     // Both __PRETTY_FUNCTION__ and __FUNCTION__ are GCC extensions, however
336     // VC++ appears to only like __FUNCTION__.
337     Builder.defineMacro("__PRETTY_FUNCTION__", "__FUNCTION__");
338     // Work around some issues with Visual C++ headerws.
339     if (LangOpts.CPlusPlus) {
340       // Since we define wchar_t in C++ mode.
341       Builder.defineMacro("_WCHAR_T_DEFINED");
342       Builder.defineMacro("_NATIVE_WCHAR_T_DEFINED");
343       // FIXME:  This should be temporary until we have a __pragma
344       // solution, to avoid some errors flagged in VC++ headers.
345       Builder.defineMacro("_CRT_SECURE_CPP_OVERLOAD_SECURE_NAMES", "0");
346       Builder.append("class type_info;");
347     }
348   }
349 
350   if (LangOpts.Optimize)
351     Builder.defineMacro("__OPTIMIZE__");
352   if (LangOpts.OptimizeSize)
353     Builder.defineMacro("__OPTIMIZE_SIZE__");
354 
355   // Initialize target-specific preprocessor defines.
356 
357   // Define type sizing macros based on the target properties.
358   assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
359   Builder.defineMacro("__CHAR_BIT__", "8");
360 
361   DefineTypeSize("__SCHAR_MAX__", TI.getCharWidth(), "", true, Builder);
362   DefineTypeSize("__SHRT_MAX__", TargetInfo::SignedShort, TI, Builder);
363   DefineTypeSize("__INT_MAX__", TargetInfo::SignedInt, TI, Builder);
364   DefineTypeSize("__LONG_MAX__", TargetInfo::SignedLong, TI, Builder);
365   DefineTypeSize("__LONG_LONG_MAX__", TargetInfo::SignedLongLong, TI, Builder);
366   DefineTypeSize("__WCHAR_MAX__", TI.getWCharType(), TI, Builder);
367   DefineTypeSize("__INTMAX_MAX__", TI.getIntMaxType(), TI, Builder);
368 
369   DefineTypeSizeof("__SIZEOF_DOUBLE__", TI.getDoubleWidth(), TI, Builder);
370   DefineTypeSizeof("__SIZEOF_FLOAT__", TI.getFloatWidth(), TI, Builder);
371   DefineTypeSizeof("__SIZEOF_INT__", TI.getIntWidth(), TI, Builder);
372   DefineTypeSizeof("__SIZEOF_LONG__", TI.getLongWidth(), TI, Builder);
373   DefineTypeSizeof("__SIZEOF_LONG_DOUBLE__",TI.getLongDoubleWidth(),TI,Builder);
374   DefineTypeSizeof("__SIZEOF_LONG_LONG__", TI.getLongLongWidth(), TI, Builder);
375   DefineTypeSizeof("__SIZEOF_POINTER__", TI.getPointerWidth(0), TI, Builder);
376   DefineTypeSizeof("__SIZEOF_SHORT__", TI.getShortWidth(), TI, Builder);
377   DefineTypeSizeof("__SIZEOF_PTRDIFF_T__",
378                    TI.getTypeWidth(TI.getPtrDiffType(0)), TI, Builder);
379   DefineTypeSizeof("__SIZEOF_SIZE_T__",
380                    TI.getTypeWidth(TI.getSizeType()), TI, Builder);
381   DefineTypeSizeof("__SIZEOF_WCHAR_T__",
382                    TI.getTypeWidth(TI.getWCharType()), TI, Builder);
383   DefineTypeSizeof("__SIZEOF_WINT_T__",
384                    TI.getTypeWidth(TI.getWIntType()), TI, Builder);
385 
386   DefineType("__INTMAX_TYPE__", TI.getIntMaxType(), Builder);
387   DefineType("__UINTMAX_TYPE__", TI.getUIntMaxType(), Builder);
388   DefineTypeWidth("__INTMAX_WIDTH__",  TI.getIntMaxType(), TI, Builder);
389   DefineType("__PTRDIFF_TYPE__", TI.getPtrDiffType(0), Builder);
390   DefineTypeWidth("__PTRDIFF_WIDTH__", TI.getPtrDiffType(0), TI, Builder);
391   DefineType("__INTPTR_TYPE__", TI.getIntPtrType(), Builder);
392   DefineTypeWidth("__INTPTR_WIDTH__", TI.getIntPtrType(), TI, Builder);
393   DefineType("__SIZE_TYPE__", TI.getSizeType(), Builder);
394   DefineTypeWidth("__SIZE_WIDTH__", TI.getSizeType(), TI, Builder);
395   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Builder);
396   DefineTypeWidth("__WCHAR_WIDTH__", TI.getWCharType(), TI, Builder);
397   DefineType("__WINT_TYPE__", TI.getWIntType(), Builder);
398   DefineTypeWidth("__WINT_WIDTH__", TI.getWIntType(), TI, Builder);
399   DefineTypeWidth("__SIG_ATOMIC_WIDTH__", TI.getSigAtomicType(), TI, Builder);
400   DefineType("__CHAR16_TYPE__", TI.getChar16Type(), Builder);
401   DefineType("__CHAR32_TYPE__", TI.getChar32Type(), Builder);
402 
403   DefineFloatMacros(Builder, "FLT", &TI.getFloatFormat());
404   DefineFloatMacros(Builder, "DBL", &TI.getDoubleFormat());
405   DefineFloatMacros(Builder, "LDBL", &TI.getLongDoubleFormat());
406 
407   // Define a __POINTER_WIDTH__ macro for stdint.h.
408   Builder.defineMacro("__POINTER_WIDTH__",
409                       llvm::Twine((int)TI.getPointerWidth(0)));
410 
411   if (!LangOpts.CharIsSigned)
412     Builder.defineMacro("__CHAR_UNSIGNED__");
413 
414   // Define exact-width integer types for stdint.h
415   Builder.defineMacro("__INT" + llvm::Twine(TI.getCharWidth()) + "_TYPE__",
416                       "char");
417 
418   if (TI.getShortWidth() > TI.getCharWidth())
419     DefineExactWidthIntType(TargetInfo::SignedShort, TI, Builder);
420 
421   if (TI.getIntWidth() > TI.getShortWidth())
422     DefineExactWidthIntType(TargetInfo::SignedInt, TI, Builder);
423 
424   if (TI.getLongWidth() > TI.getIntWidth())
425     DefineExactWidthIntType(TargetInfo::SignedLong, TI, Builder);
426 
427   if (TI.getLongLongWidth() > TI.getLongWidth())
428     DefineExactWidthIntType(TargetInfo::SignedLongLong, TI, Builder);
429 
430   // Add __builtin_va_list typedef.
431   Builder.append(TI.getVAListDeclaration());
432 
433   if (const char *Prefix = TI.getUserLabelPrefix())
434     Builder.defineMacro("__USER_LABEL_PREFIX__", Prefix);
435 
436   // Build configuration options.  FIXME: these should be controlled by
437   // command line options or something.
438   Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
439 
440   if (LangOpts.GNUInline)
441     Builder.defineMacro("__GNUC_GNU_INLINE__");
442   else
443     Builder.defineMacro("__GNUC_STDC_INLINE__");
444 
445   if (LangOpts.NoInline)
446     Builder.defineMacro("__NO_INLINE__");
447 
448   if (unsigned PICLevel = LangOpts.PICLevel) {
449     Builder.defineMacro("__PIC__", llvm::Twine(PICLevel));
450     Builder.defineMacro("__pic__", llvm::Twine(PICLevel));
451   }
452 
453   // Macros to control C99 numerics and <float.h>
454   Builder.defineMacro("__FLT_EVAL_METHOD__", "0");
455   Builder.defineMacro("__FLT_RADIX__", "2");
456   int Dig = PickFP(&TI.getLongDoubleFormat(), -1/*FIXME*/, 17, 21, 33, 36);
457   Builder.defineMacro("__DECIMAL_DIG__", llvm::Twine(Dig));
458 
459   if (LangOpts.getStackProtectorMode() == LangOptions::SSPOn)
460     Builder.defineMacro("__SSP__");
461   else if (LangOpts.getStackProtectorMode() == LangOptions::SSPReq)
462     Builder.defineMacro("__SSP_ALL__", "2");
463 
464   if (FEOpts.ProgramAction == frontend::RewriteObjC)
465     Builder.defineMacro("__weak", "__attribute__((objc_gc(weak)))");
466 
467   // Define a macro that exists only when using the static analyzer.
468   if (FEOpts.ProgramAction == frontend::RunAnalysis)
469     Builder.defineMacro("__clang_analyzer__");
470 
471   // Get other target #defines.
472   TI.getTargetDefines(LangOpts, Builder);
473 }
474 
475 // Initialize the remapping of files to alternative contents, e.g.,
476 // those specified through other files.
477 static void InitializeFileRemapping(Diagnostic &Diags,
478                                     SourceManager &SourceMgr,
479                                     FileManager &FileMgr,
480                                     const PreprocessorOptions &InitOpts) {
481   // Remap files in the source manager (with buffers).
482   for (PreprocessorOptions::const_remapped_file_buffer_iterator
483          Remap = InitOpts.remapped_file_buffer_begin(),
484          RemapEnd = InitOpts.remapped_file_buffer_end();
485        Remap != RemapEnd;
486        ++Remap) {
487     // Create the file entry for the file that we're mapping from.
488     const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
489                                                 Remap->second->getBufferSize(),
490                                                        0);
491     if (!FromFile) {
492       Diags.Report(diag::err_fe_remap_missing_from_file)
493         << Remap->first;
494       if (!InitOpts.RetainRemappedFileBuffers)
495         delete Remap->second;
496       continue;
497     }
498 
499     // Override the contents of the "from" file with the contents of
500     // the "to" file.
501     SourceMgr.overrideFileContents(FromFile, Remap->second,
502                                    InitOpts.RetainRemappedFileBuffers);
503   }
504 
505   // Remap files in the source manager (with other files).
506   for (PreprocessorOptions::const_remapped_file_iterator
507          Remap = InitOpts.remapped_file_begin(),
508          RemapEnd = InitOpts.remapped_file_end();
509        Remap != RemapEnd;
510        ++Remap) {
511     // Find the file that we're mapping to.
512     const FileEntry *ToFile = FileMgr.getFile(Remap->second);
513     if (!ToFile) {
514       Diags.Report(diag::err_fe_remap_missing_to_file)
515       << Remap->first << Remap->second;
516       continue;
517     }
518 
519     // Create the file entry for the file that we're mapping from.
520     const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
521                                                        ToFile->getSize(),
522                                                        0);
523     if (!FromFile) {
524       Diags.Report(diag::err_fe_remap_missing_from_file)
525       << Remap->first;
526       continue;
527     }
528 
529     // Load the contents of the file we're mapping to.
530     std::string ErrorStr;
531     const llvm::MemoryBuffer *Buffer
532     = llvm::MemoryBuffer::getFile(ToFile->getName(), &ErrorStr);
533     if (!Buffer) {
534       Diags.Report(diag::err_fe_error_opening)
535         << Remap->second << ErrorStr;
536       continue;
537     }
538 
539     // Override the contents of the "from" file with the contents of
540     // the "to" file.
541     SourceMgr.overrideFileContents(FromFile, Buffer);
542   }
543 }
544 
545 /// InitializePreprocessor - Initialize the preprocessor getting it and the
546 /// environment ready to process a single file. This returns true on error.
547 ///
548 void clang::InitializePreprocessor(Preprocessor &PP,
549                                    const PreprocessorOptions &InitOpts,
550                                    const HeaderSearchOptions &HSOpts,
551                                    const FrontendOptions &FEOpts) {
552   std::string PredefineBuffer;
553   PredefineBuffer.reserve(4080);
554   llvm::raw_string_ostream Predefines(PredefineBuffer);
555   MacroBuilder Builder(Predefines);
556 
557   InitializeFileRemapping(PP.getDiagnostics(), PP.getSourceManager(),
558                           PP.getFileManager(), InitOpts);
559 
560   // Emit line markers for various builtin sections of the file.  We don't do
561   // this in asm preprocessor mode, because "# 4" is not a line marker directive
562   // in this mode.
563   if (!PP.getLangOptions().AsmPreprocessor)
564     Builder.append("# 1 \"<built-in>\" 3");
565 
566   // Install things like __POWERPC__, __GNUC__, etc into the macro table.
567   if (InitOpts.UsePredefines)
568     InitializePredefinedMacros(PP.getTargetInfo(), PP.getLangOptions(),
569                                FEOpts, Builder);
570 
571   // Add on the predefines from the driver.  Wrap in a #line directive to report
572   // that they come from the command line.
573   if (!PP.getLangOptions().AsmPreprocessor)
574     Builder.append("# 1 \"<command line>\" 1");
575 
576   // Process #define's and #undef's in the order they are given.
577   for (unsigned i = 0, e = InitOpts.Macros.size(); i != e; ++i) {
578     if (InitOpts.Macros[i].second)  // isUndef
579       Builder.undefineMacro(InitOpts.Macros[i].first);
580     else
581       DefineBuiltinMacro(Builder, InitOpts.Macros[i].first,
582                          PP.getDiagnostics());
583   }
584 
585   // If -imacros are specified, include them now.  These are processed before
586   // any -include directives.
587   for (unsigned i = 0, e = InitOpts.MacroIncludes.size(); i != e; ++i)
588     AddImplicitIncludeMacros(Builder, InitOpts.MacroIncludes[i]);
589 
590   // Process -include directives.
591   for (unsigned i = 0, e = InitOpts.Includes.size(); i != e; ++i) {
592     const std::string &Path = InitOpts.Includes[i];
593     if (Path == InitOpts.ImplicitPTHInclude)
594       AddImplicitIncludePTH(Builder, PP, Path);
595     else
596       AddImplicitInclude(Builder, Path);
597   }
598 
599   // Exit the command line and go back to <built-in> (2 is LC_LEAVE).
600   if (!PP.getLangOptions().AsmPreprocessor)
601     Builder.append("# 1 \"<built-in>\" 2");
602 
603   // Instruct the preprocessor to skip the preamble.
604   PP.setSkipMainFilePreamble(InitOpts.PrecompiledPreambleBytes.first,
605                              InitOpts.PrecompiledPreambleBytes.second);
606 
607   // Copy PredefinedBuffer into the Preprocessor.
608   PP.setPredefines(Predefines.str());
609 
610   // Initialize the header search object.
611   ApplyHeaderSearchOptions(PP.getHeaderSearchInfo(), HSOpts,
612                            PP.getLangOptions(),
613                            PP.getTargetInfo().getTriple());
614 }
615