xref: /llvm-project/clang/lib/Frontend/InitPreprocessor.cpp (revision 5b6207f3cd5e266f3fda8085fcebe6dcf45dacbf)
1 //===--- InitPreprocessor.cpp - PP initialization code. ---------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the clang::InitializePreprocessor function.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/Basic/FileManager.h"
14 #include "clang/Basic/MacroBuilder.h"
15 #include "clang/Basic/SourceManager.h"
16 #include "clang/Basic/SyncScope.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Basic/Version.h"
19 #include "clang/Frontend/FrontendDiagnostic.h"
20 #include "clang/Frontend/FrontendOptions.h"
21 #include "clang/Frontend/Utils.h"
22 #include "clang/Lex/HeaderSearch.h"
23 #include "clang/Lex/Preprocessor.h"
24 #include "clang/Lex/PreprocessorOptions.h"
25 #include "clang/Serialization/ASTReader.h"
26 #include "llvm/ADT/APFloat.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/DerivedTypes.h"
29 using namespace clang;
30 
31 static bool MacroBodyEndsInBackslash(StringRef MacroBody) {
32   while (!MacroBody.empty() && isWhitespace(MacroBody.back()))
33     MacroBody = MacroBody.drop_back();
34   return !MacroBody.empty() && MacroBody.back() == '\\';
35 }
36 
37 // Append a #define line to Buf for Macro.  Macro should be of the form XXX,
38 // in which case we emit "#define XXX 1" or "XXX=Y z W" in which case we emit
39 // "#define XXX Y z W".  To get a #define with no value, use "XXX=".
40 static void DefineBuiltinMacro(MacroBuilder &Builder, StringRef Macro,
41                                DiagnosticsEngine &Diags) {
42   std::pair<StringRef, StringRef> MacroPair = Macro.split('=');
43   StringRef MacroName = MacroPair.first;
44   StringRef MacroBody = MacroPair.second;
45   if (MacroName.size() != Macro.size()) {
46     // Per GCC -D semantics, the macro ends at \n if it exists.
47     StringRef::size_type End = MacroBody.find_first_of("\n\r");
48     if (End != StringRef::npos)
49       Diags.Report(diag::warn_fe_macro_contains_embedded_newline)
50         << MacroName;
51     MacroBody = MacroBody.substr(0, End);
52     // We handle macro bodies which end in a backslash by appending an extra
53     // backslash+newline.  This makes sure we don't accidentally treat the
54     // backslash as a line continuation marker.
55     if (MacroBodyEndsInBackslash(MacroBody))
56       Builder.defineMacro(MacroName, Twine(MacroBody) + "\\\n");
57     else
58       Builder.defineMacro(MacroName, MacroBody);
59   } else {
60     // Push "macroname 1".
61     Builder.defineMacro(Macro);
62   }
63 }
64 
65 /// AddImplicitInclude - Add an implicit \#include of the specified file to the
66 /// predefines buffer.
67 /// As these includes are generated by -include arguments the header search
68 /// logic is going to search relatively to the current working directory.
69 static void AddImplicitInclude(MacroBuilder &Builder, StringRef File) {
70   Builder.append(Twine("#include \"") + File + "\"");
71 }
72 
73 static void AddImplicitIncludeMacros(MacroBuilder &Builder, StringRef File) {
74   Builder.append(Twine("#__include_macros \"") + File + "\"");
75   // Marker token to stop the __include_macros fetch loop.
76   Builder.append("##"); // ##?
77 }
78 
79 /// Add an implicit \#include using the original file used to generate
80 /// a PCH file.
81 static void AddImplicitIncludePCH(MacroBuilder &Builder, Preprocessor &PP,
82                                   const PCHContainerReader &PCHContainerRdr,
83                                   StringRef ImplicitIncludePCH) {
84   std::string OriginalFile = ASTReader::getOriginalSourceFile(
85       std::string(ImplicitIncludePCH), PP.getFileManager(), PCHContainerRdr,
86       PP.getDiagnostics());
87   if (OriginalFile.empty())
88     return;
89 
90   AddImplicitInclude(Builder, OriginalFile);
91 }
92 
93 /// PickFP - This is used to pick a value based on the FP semantics of the
94 /// specified FP model.
95 template <typename T>
96 static T PickFP(const llvm::fltSemantics *Sem, T IEEEHalfVal, T IEEESingleVal,
97                 T IEEEDoubleVal, T X87DoubleExtendedVal, T PPCDoubleDoubleVal,
98                 T IEEEQuadVal) {
99   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEhalf())
100     return IEEEHalfVal;
101   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEsingle())
102     return IEEESingleVal;
103   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEdouble())
104     return IEEEDoubleVal;
105   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::x87DoubleExtended())
106     return X87DoubleExtendedVal;
107   if (Sem == (const llvm::fltSemantics*)&llvm::APFloat::PPCDoubleDouble())
108     return PPCDoubleDoubleVal;
109   assert(Sem == (const llvm::fltSemantics*)&llvm::APFloat::IEEEquad());
110   return IEEEQuadVal;
111 }
112 
113 static void DefineFloatMacros(MacroBuilder &Builder, StringRef Prefix,
114                               const llvm::fltSemantics *Sem, StringRef Ext) {
115   const char *DenormMin, *Epsilon, *Max, *Min;
116   DenormMin = PickFP(Sem, "5.9604644775390625e-8", "1.40129846e-45",
117                      "4.9406564584124654e-324", "3.64519953188247460253e-4951",
118                      "4.94065645841246544176568792868221e-324",
119                      "6.47517511943802511092443895822764655e-4966");
120   int Digits = PickFP(Sem, 3, 6, 15, 18, 31, 33);
121   int DecimalDigits = PickFP(Sem, 5, 9, 17, 21, 33, 36);
122   Epsilon = PickFP(Sem, "9.765625e-4", "1.19209290e-7",
123                    "2.2204460492503131e-16", "1.08420217248550443401e-19",
124                    "4.94065645841246544176568792868221e-324",
125                    "1.92592994438723585305597794258492732e-34");
126   int MantissaDigits = PickFP(Sem, 11, 24, 53, 64, 106, 113);
127   int Min10Exp = PickFP(Sem, -4, -37, -307, -4931, -291, -4931);
128   int Max10Exp = PickFP(Sem, 4, 38, 308, 4932, 308, 4932);
129   int MinExp = PickFP(Sem, -13, -125, -1021, -16381, -968, -16381);
130   int MaxExp = PickFP(Sem, 16, 128, 1024, 16384, 1024, 16384);
131   Min = PickFP(Sem, "6.103515625e-5", "1.17549435e-38", "2.2250738585072014e-308",
132                "3.36210314311209350626e-4932",
133                "2.00416836000897277799610805135016e-292",
134                "3.36210314311209350626267781732175260e-4932");
135   Max = PickFP(Sem, "6.5504e+4", "3.40282347e+38", "1.7976931348623157e+308",
136                "1.18973149535723176502e+4932",
137                "1.79769313486231580793728971405301e+308",
138                "1.18973149535723176508575932662800702e+4932");
139 
140   SmallString<32> DefPrefix;
141   DefPrefix = "__";
142   DefPrefix += Prefix;
143   DefPrefix += "_";
144 
145   Builder.defineMacro(DefPrefix + "DENORM_MIN__", Twine(DenormMin)+Ext);
146   Builder.defineMacro(DefPrefix + "HAS_DENORM__");
147   Builder.defineMacro(DefPrefix + "DIG__", Twine(Digits));
148   Builder.defineMacro(DefPrefix + "DECIMAL_DIG__", Twine(DecimalDigits));
149   Builder.defineMacro(DefPrefix + "EPSILON__", Twine(Epsilon)+Ext);
150   Builder.defineMacro(DefPrefix + "HAS_INFINITY__");
151   Builder.defineMacro(DefPrefix + "HAS_QUIET_NAN__");
152   Builder.defineMacro(DefPrefix + "MANT_DIG__", Twine(MantissaDigits));
153 
154   Builder.defineMacro(DefPrefix + "MAX_10_EXP__", Twine(Max10Exp));
155   Builder.defineMacro(DefPrefix + "MAX_EXP__", Twine(MaxExp));
156   Builder.defineMacro(DefPrefix + "MAX__", Twine(Max)+Ext);
157 
158   Builder.defineMacro(DefPrefix + "MIN_10_EXP__","("+Twine(Min10Exp)+")");
159   Builder.defineMacro(DefPrefix + "MIN_EXP__", "("+Twine(MinExp)+")");
160   Builder.defineMacro(DefPrefix + "MIN__", Twine(Min)+Ext);
161 }
162 
163 
164 /// DefineTypeSize - Emit a macro to the predefines buffer that declares a macro
165 /// named MacroName with the max value for a type with width 'TypeWidth' a
166 /// signedness of 'isSigned' and with a value suffix of 'ValSuffix' (e.g. LL).
167 static void DefineTypeSize(const Twine &MacroName, unsigned TypeWidth,
168                            StringRef ValSuffix, bool isSigned,
169                            MacroBuilder &Builder) {
170   llvm::APInt MaxVal = isSigned ? llvm::APInt::getSignedMaxValue(TypeWidth)
171                                 : llvm::APInt::getMaxValue(TypeWidth);
172   Builder.defineMacro(MacroName, toString(MaxVal, 10, isSigned) + ValSuffix);
173 }
174 
175 /// DefineTypeSize - An overloaded helper that uses TargetInfo to determine
176 /// the width, suffix, and signedness of the given type
177 static void DefineTypeSize(const Twine &MacroName, TargetInfo::IntType Ty,
178                            const TargetInfo &TI, MacroBuilder &Builder) {
179   DefineTypeSize(MacroName, TI.getTypeWidth(Ty), TI.getTypeConstantSuffix(Ty),
180                  TI.isTypeSigned(Ty), Builder);
181 }
182 
183 static void DefineFmt(const Twine &Prefix, TargetInfo::IntType Ty,
184                       const TargetInfo &TI, MacroBuilder &Builder) {
185   bool IsSigned = TI.isTypeSigned(Ty);
186   StringRef FmtModifier = TI.getTypeFormatModifier(Ty);
187   for (const char *Fmt = IsSigned ? "di" : "ouxX"; *Fmt; ++Fmt) {
188     Builder.defineMacro(Prefix + "_FMT" + Twine(*Fmt) + "__",
189                         Twine("\"") + FmtModifier + Twine(*Fmt) + "\"");
190   }
191 }
192 
193 static void DefineType(const Twine &MacroName, TargetInfo::IntType Ty,
194                        MacroBuilder &Builder) {
195   Builder.defineMacro(MacroName, TargetInfo::getTypeName(Ty));
196 }
197 
198 static void DefineTypeWidth(const Twine &MacroName, TargetInfo::IntType Ty,
199                             const TargetInfo &TI, MacroBuilder &Builder) {
200   Builder.defineMacro(MacroName, Twine(TI.getTypeWidth(Ty)));
201 }
202 
203 static void DefineTypeSizeof(StringRef MacroName, unsigned BitWidth,
204                              const TargetInfo &TI, MacroBuilder &Builder) {
205   Builder.defineMacro(MacroName,
206                       Twine(BitWidth / TI.getCharWidth()));
207 }
208 
209 // This will generate a macro based on the prefix with `_MAX__` as the suffix
210 // for the max value representable for the type, and a macro with a `_WIDTH__`
211 // suffix for the width of the type.
212 static void DefineTypeSizeAndWidth(const Twine &Prefix, TargetInfo::IntType Ty,
213                                    const TargetInfo &TI,
214                                    MacroBuilder &Builder) {
215   DefineTypeSize(Prefix + "_MAX__", Ty, TI, Builder);
216   DefineTypeWidth(Prefix + "_WIDTH__", Ty, TI, Builder);
217 }
218 
219 static void DefineExactWidthIntType(TargetInfo::IntType Ty,
220                                     const TargetInfo &TI,
221                                     MacroBuilder &Builder) {
222   int TypeWidth = TI.getTypeWidth(Ty);
223   bool IsSigned = TI.isTypeSigned(Ty);
224 
225   // Use the target specified int64 type, when appropriate, so that [u]int64_t
226   // ends up being defined in terms of the correct type.
227   if (TypeWidth == 64)
228     Ty = IsSigned ? TI.getInt64Type() : TI.getUInt64Type();
229 
230   // Use the target specified int16 type when appropriate. Some MCU targets
231   // (such as AVR) have definition of [u]int16_t to [un]signed int.
232   if (TypeWidth == 16)
233     Ty = IsSigned ? TI.getInt16Type() : TI.getUInt16Type();
234 
235   const char *Prefix = IsSigned ? "__INT" : "__UINT";
236 
237   DefineType(Prefix + Twine(TypeWidth) + "_TYPE__", Ty, Builder);
238   DefineFmt(Prefix + Twine(TypeWidth), Ty, TI, Builder);
239 
240   StringRef ConstSuffix(TI.getTypeConstantSuffix(Ty));
241   Builder.defineMacro(Prefix + Twine(TypeWidth) + "_C_SUFFIX__", ConstSuffix);
242 }
243 
244 static void DefineExactWidthIntTypeSize(TargetInfo::IntType Ty,
245                                         const TargetInfo &TI,
246                                         MacroBuilder &Builder) {
247   int TypeWidth = TI.getTypeWidth(Ty);
248   bool IsSigned = TI.isTypeSigned(Ty);
249 
250   // Use the target specified int64 type, when appropriate, so that [u]int64_t
251   // ends up being defined in terms of the correct type.
252   if (TypeWidth == 64)
253     Ty = IsSigned ? TI.getInt64Type() : TI.getUInt64Type();
254 
255   // We don't need to define a _WIDTH macro for the exact-width types because
256   // we already know the width.
257   const char *Prefix = IsSigned ? "__INT" : "__UINT";
258   DefineTypeSize(Prefix + Twine(TypeWidth) + "_MAX__", Ty, TI, Builder);
259 }
260 
261 static void DefineLeastWidthIntType(unsigned TypeWidth, bool IsSigned,
262                                     const TargetInfo &TI,
263                                     MacroBuilder &Builder) {
264   TargetInfo::IntType Ty = TI.getLeastIntTypeByWidth(TypeWidth, IsSigned);
265   if (Ty == TargetInfo::NoInt)
266     return;
267 
268   const char *Prefix = IsSigned ? "__INT_LEAST" : "__UINT_LEAST";
269   DefineType(Prefix + Twine(TypeWidth) + "_TYPE__", Ty, Builder);
270   // We only want the *_WIDTH macro for the signed types to avoid too many
271   // predefined macros (the unsigned width and the signed width are identical.)
272   if (IsSigned)
273     DefineTypeSizeAndWidth(Prefix + Twine(TypeWidth), Ty, TI, Builder);
274   else
275     DefineTypeSize(Prefix + Twine(TypeWidth) + "_MAX__", Ty, TI, Builder);
276   DefineFmt(Prefix + Twine(TypeWidth), Ty, TI, Builder);
277 }
278 
279 static void DefineFastIntType(unsigned TypeWidth, bool IsSigned,
280                               const TargetInfo &TI, MacroBuilder &Builder) {
281   // stdint.h currently defines the fast int types as equivalent to the least
282   // types.
283   TargetInfo::IntType Ty = TI.getLeastIntTypeByWidth(TypeWidth, IsSigned);
284   if (Ty == TargetInfo::NoInt)
285     return;
286 
287   const char *Prefix = IsSigned ? "__INT_FAST" : "__UINT_FAST";
288   DefineType(Prefix + Twine(TypeWidth) + "_TYPE__", Ty, Builder);
289   // We only want the *_WIDTH macro for the signed types to avoid too many
290   // predefined macros (the unsigned width and the signed width are identical.)
291   if (IsSigned)
292     DefineTypeSizeAndWidth(Prefix + Twine(TypeWidth), Ty, TI, Builder);
293   else
294     DefineTypeSize(Prefix + Twine(TypeWidth) + "_MAX__", Ty, TI, Builder);
295   DefineFmt(Prefix + Twine(TypeWidth), Ty, TI, Builder);
296 }
297 
298 
299 /// Get the value the ATOMIC_*_LOCK_FREE macro should have for a type with
300 /// the specified properties.
301 static const char *getLockFreeValue(unsigned TypeWidth, unsigned TypeAlign,
302                                     unsigned InlineWidth) {
303   // Fully-aligned, power-of-2 sizes no larger than the inline
304   // width will be inlined as lock-free operations.
305   if (TypeWidth == TypeAlign && (TypeWidth & (TypeWidth - 1)) == 0 &&
306       TypeWidth <= InlineWidth)
307     return "2"; // "always lock free"
308   // We cannot be certain what operations the lib calls might be
309   // able to implement as lock-free on future processors.
310   return "1"; // "sometimes lock free"
311 }
312 
313 /// Add definitions required for a smooth interaction between
314 /// Objective-C++ automated reference counting and libstdc++ (4.2).
315 static void AddObjCXXARCLibstdcxxDefines(const LangOptions &LangOpts,
316                                          MacroBuilder &Builder) {
317   Builder.defineMacro("_GLIBCXX_PREDEFINED_OBJC_ARC_IS_SCALAR");
318 
319   std::string Result;
320   {
321     // Provide specializations for the __is_scalar type trait so that
322     // lifetime-qualified objects are not considered "scalar" types, which
323     // libstdc++ uses as an indicator of the presence of trivial copy, assign,
324     // default-construct, and destruct semantics (none of which hold for
325     // lifetime-qualified objects in ARC).
326     llvm::raw_string_ostream Out(Result);
327 
328     Out << "namespace std {\n"
329         << "\n"
330         << "struct __true_type;\n"
331         << "struct __false_type;\n"
332         << "\n";
333 
334     Out << "template<typename _Tp> struct __is_scalar;\n"
335         << "\n";
336 
337     if (LangOpts.ObjCAutoRefCount) {
338       Out << "template<typename _Tp>\n"
339           << "struct __is_scalar<__attribute__((objc_ownership(strong))) _Tp> {\n"
340           << "  enum { __value = 0 };\n"
341           << "  typedef __false_type __type;\n"
342           << "};\n"
343           << "\n";
344     }
345 
346     if (LangOpts.ObjCWeak) {
347       Out << "template<typename _Tp>\n"
348           << "struct __is_scalar<__attribute__((objc_ownership(weak))) _Tp> {\n"
349           << "  enum { __value = 0 };\n"
350           << "  typedef __false_type __type;\n"
351           << "};\n"
352           << "\n";
353     }
354 
355     if (LangOpts.ObjCAutoRefCount) {
356       Out << "template<typename _Tp>\n"
357           << "struct __is_scalar<__attribute__((objc_ownership(autoreleasing)))"
358           << " _Tp> {\n"
359           << "  enum { __value = 0 };\n"
360           << "  typedef __false_type __type;\n"
361           << "};\n"
362           << "\n";
363     }
364 
365     Out << "}\n";
366   }
367   Builder.append(Result);
368 }
369 
370 static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
371                                                const LangOptions &LangOpts,
372                                                const FrontendOptions &FEOpts,
373                                                MacroBuilder &Builder) {
374   if (LangOpts.HLSL) {
375     Builder.defineMacro("__hlsl_clang");
376     // HLSL Version
377     Builder.defineMacro("__HLSL_VERSION",
378                         Twine((unsigned)LangOpts.getHLSLVersion()));
379 
380     // Shader target information
381     // "enums" for shader stages
382     Builder.defineMacro("__SHADER_STAGE_VERTEX",
383                         Twine((uint32_t)ShaderStage::Vertex));
384     Builder.defineMacro("__SHADER_STAGE_PIXEL",
385                         Twine((uint32_t)ShaderStage::Pixel));
386     Builder.defineMacro("__SHADER_STAGE_GEOMETRY",
387                         Twine((uint32_t)ShaderStage::Geometry));
388     Builder.defineMacro("__SHADER_STAGE_HULL",
389                         Twine((uint32_t)ShaderStage::Hull));
390     Builder.defineMacro("__SHADER_STAGE_DOMAIN",
391                         Twine((uint32_t)ShaderStage::Domain));
392     Builder.defineMacro("__SHADER_STAGE_COMPUTE",
393                         Twine((uint32_t)ShaderStage::Compute));
394     Builder.defineMacro("__SHADER_STAGE_AMPLIFICATION",
395                         Twine((uint32_t)ShaderStage::Amplification));
396     Builder.defineMacro("__SHADER_STAGE_MESH",
397                         Twine((uint32_t)ShaderStage::Mesh));
398     Builder.defineMacro("__SHADER_STAGE_LIBRARY",
399                         Twine((uint32_t)ShaderStage::Library));
400     // The current shader stage itself
401     uint32_t StageInteger = StageInteger =
402         (uint32_t)TI.getTriple().getEnvironment() -
403         (uint32_t)llvm::Triple::Pixel;
404 
405     Builder.defineMacro("__SHADER_TARGET_STAGE", Twine(StageInteger));
406     // Add target versions
407     if (TI.getTriple().getOS() == llvm::Triple::ShaderModel) {
408       VersionTuple Version = TI.getTriple().getOSVersion();
409       Builder.defineMacro("__SHADER_TARGET_MAJOR", Twine(Version.getMajor()));
410       unsigned Minor = Version.getMinor() ? *Version.getMinor() : 0;
411       Builder.defineMacro("__SHADER_TARGET_MINOR", Twine(Minor));
412     }
413     return;
414   }
415   // C++ [cpp.predefined]p1:
416   //   The following macro names shall be defined by the implementation:
417 
418   //   -- __STDC__
419   //      [C++] Whether __STDC__ is predefined and if so, what its value is,
420   //      are implementation-defined.
421   // (Removed in C++20.)
422   if (!LangOpts.MSVCCompat && !LangOpts.TraditionalCPP)
423     Builder.defineMacro("__STDC__");
424   //   -- __STDC_HOSTED__
425   //      The integer literal 1 if the implementation is a hosted
426   //      implementation or the integer literal 0 if it is not.
427   if (LangOpts.Freestanding)
428     Builder.defineMacro("__STDC_HOSTED__", "0");
429   else
430     Builder.defineMacro("__STDC_HOSTED__");
431 
432   //   -- __STDC_VERSION__
433   //      [C++] Whether __STDC_VERSION__ is predefined and if so, what its
434   //      value is, are implementation-defined.
435   // (Removed in C++20.)
436   if (!LangOpts.CPlusPlus) {
437     // FIXME: Use correct value for C23.
438     if (LangOpts.C2x)
439       Builder.defineMacro("__STDC_VERSION__", "202000L");
440     else if (LangOpts.C17)
441       Builder.defineMacro("__STDC_VERSION__", "201710L");
442     else if (LangOpts.C11)
443       Builder.defineMacro("__STDC_VERSION__", "201112L");
444     else if (LangOpts.C99)
445       Builder.defineMacro("__STDC_VERSION__", "199901L");
446     else if (!LangOpts.GNUMode && LangOpts.Digraphs)
447       Builder.defineMacro("__STDC_VERSION__", "199409L");
448   } else {
449     //   -- __cplusplus
450     // FIXME: Use correct value for C++23.
451     if (LangOpts.CPlusPlus2b)
452       Builder.defineMacro("__cplusplus", "202101L");
453     //      [C++20] The integer literal 202002L.
454     else if (LangOpts.CPlusPlus20)
455       Builder.defineMacro("__cplusplus", "202002L");
456     //      [C++17] The integer literal 201703L.
457     else if (LangOpts.CPlusPlus17)
458       Builder.defineMacro("__cplusplus", "201703L");
459     //      [C++14] The name __cplusplus is defined to the value 201402L when
460     //      compiling a C++ translation unit.
461     else if (LangOpts.CPlusPlus14)
462       Builder.defineMacro("__cplusplus", "201402L");
463     //      [C++11] The name __cplusplus is defined to the value 201103L when
464     //      compiling a C++ translation unit.
465     else if (LangOpts.CPlusPlus11)
466       Builder.defineMacro("__cplusplus", "201103L");
467     //      [C++03] The name __cplusplus is defined to the value 199711L when
468     //      compiling a C++ translation unit.
469     else
470       Builder.defineMacro("__cplusplus", "199711L");
471 
472     //   -- __STDCPP_DEFAULT_NEW_ALIGNMENT__
473     //      [C++17] An integer literal of type std::size_t whose value is the
474     //      alignment guaranteed by a call to operator new(std::size_t)
475     //
476     // We provide this in all language modes, since it seems generally useful.
477     Builder.defineMacro("__STDCPP_DEFAULT_NEW_ALIGNMENT__",
478                         Twine(TI.getNewAlign() / TI.getCharWidth()) +
479                             TI.getTypeConstantSuffix(TI.getSizeType()));
480 
481     //   -- __STDCPP_­THREADS__
482     //      Defined, and has the value integer literal 1, if and only if a
483     //      program can have more than one thread of execution.
484     if (LangOpts.getThreadModel() == LangOptions::ThreadModelKind::POSIX)
485       Builder.defineMacro("__STDCPP_THREADS__", "1");
486   }
487 
488   // In C11 these are environment macros. In C++11 they are only defined
489   // as part of <cuchar>. To prevent breakage when mixing C and C++
490   // code, define these macros unconditionally. We can define them
491   // unconditionally, as Clang always uses UTF-16 and UTF-32 for 16-bit
492   // and 32-bit character literals.
493   Builder.defineMacro("__STDC_UTF_16__", "1");
494   Builder.defineMacro("__STDC_UTF_32__", "1");
495 
496   if (LangOpts.ObjC)
497     Builder.defineMacro("__OBJC__");
498 
499   // OpenCL v1.0/1.1 s6.9, v1.2/2.0 s6.10: Preprocessor Directives and Macros.
500   if (LangOpts.OpenCL) {
501     if (LangOpts.CPlusPlus) {
502       switch (LangOpts.OpenCLCPlusPlusVersion) {
503       case 100:
504         Builder.defineMacro("__OPENCL_CPP_VERSION__", "100");
505         break;
506       case 202100:
507         Builder.defineMacro("__OPENCL_CPP_VERSION__", "202100");
508         break;
509       default:
510         llvm_unreachable("Unsupported C++ version for OpenCL");
511       }
512       Builder.defineMacro("__CL_CPP_VERSION_1_0__", "100");
513       Builder.defineMacro("__CL_CPP_VERSION_2021__", "202100");
514     } else {
515       // OpenCL v1.0 and v1.1 do not have a predefined macro to indicate the
516       // language standard with which the program is compiled. __OPENCL_VERSION__
517       // is for the OpenCL version supported by the OpenCL device, which is not
518       // necessarily the language standard with which the program is compiled.
519       // A shared OpenCL header file requires a macro to indicate the language
520       // standard. As a workaround, __OPENCL_C_VERSION__ is defined for
521       // OpenCL v1.0 and v1.1.
522       switch (LangOpts.OpenCLVersion) {
523       case 100:
524         Builder.defineMacro("__OPENCL_C_VERSION__", "100");
525         break;
526       case 110:
527         Builder.defineMacro("__OPENCL_C_VERSION__", "110");
528         break;
529       case 120:
530         Builder.defineMacro("__OPENCL_C_VERSION__", "120");
531         break;
532       case 200:
533         Builder.defineMacro("__OPENCL_C_VERSION__", "200");
534         break;
535       case 300:
536         Builder.defineMacro("__OPENCL_C_VERSION__", "300");
537         break;
538       default:
539         llvm_unreachable("Unsupported OpenCL version");
540       }
541     }
542     Builder.defineMacro("CL_VERSION_1_0", "100");
543     Builder.defineMacro("CL_VERSION_1_1", "110");
544     Builder.defineMacro("CL_VERSION_1_2", "120");
545     Builder.defineMacro("CL_VERSION_2_0", "200");
546     Builder.defineMacro("CL_VERSION_3_0", "300");
547 
548     if (TI.isLittleEndian())
549       Builder.defineMacro("__ENDIAN_LITTLE__");
550 
551     if (LangOpts.FastRelaxedMath)
552       Builder.defineMacro("__FAST_RELAXED_MATH__");
553   }
554 
555   if (LangOpts.SYCLIsDevice || LangOpts.SYCLIsHost) {
556     // SYCL Version is set to a value when building SYCL applications
557     if (LangOpts.getSYCLVersion() == LangOptions::SYCL_2017)
558       Builder.defineMacro("CL_SYCL_LANGUAGE_VERSION", "121");
559     else if (LangOpts.getSYCLVersion() == LangOptions::SYCL_2020)
560       Builder.defineMacro("SYCL_LANGUAGE_VERSION", "202001");
561   }
562 
563   // Not "standard" per se, but available even with the -undef flag.
564   if (LangOpts.AsmPreprocessor)
565     Builder.defineMacro("__ASSEMBLER__");
566   if (LangOpts.CUDA) {
567     if (LangOpts.GPURelocatableDeviceCode)
568       Builder.defineMacro("__CLANG_RDC__");
569     if (!LangOpts.HIP)
570       Builder.defineMacro("__CUDA__");
571   }
572   if (LangOpts.HIP) {
573     Builder.defineMacro("__HIP__");
574     Builder.defineMacro("__HIPCC__");
575     Builder.defineMacro("__HIP_MEMORY_SCOPE_SINGLETHREAD", "1");
576     Builder.defineMacro("__HIP_MEMORY_SCOPE_WAVEFRONT", "2");
577     Builder.defineMacro("__HIP_MEMORY_SCOPE_WORKGROUP", "3");
578     Builder.defineMacro("__HIP_MEMORY_SCOPE_AGENT", "4");
579     Builder.defineMacro("__HIP_MEMORY_SCOPE_SYSTEM", "5");
580     if (LangOpts.CUDAIsDevice)
581       Builder.defineMacro("__HIP_DEVICE_COMPILE__");
582     if (LangOpts.GPUDefaultStream ==
583         LangOptions::GPUDefaultStreamKind::PerThread)
584       Builder.defineMacro("HIP_API_PER_THREAD_DEFAULT_STREAM");
585   }
586 }
587 
588 /// Initialize the predefined C++ language feature test macros defined in
589 /// ISO/IEC JTC1/SC22/WG21 (C++) SD-6: "SG10 Feature Test Recommendations".
590 static void InitializeCPlusPlusFeatureTestMacros(const LangOptions &LangOpts,
591                                                  MacroBuilder &Builder) {
592   // C++98 features.
593   if (LangOpts.RTTI)
594     Builder.defineMacro("__cpp_rtti", "199711L");
595   if (LangOpts.CXXExceptions)
596     Builder.defineMacro("__cpp_exceptions", "199711L");
597 
598   // C++11 features.
599   if (LangOpts.CPlusPlus11) {
600     Builder.defineMacro("__cpp_unicode_characters", "200704L");
601     Builder.defineMacro("__cpp_raw_strings", "200710L");
602     Builder.defineMacro("__cpp_unicode_literals", "200710L");
603     Builder.defineMacro("__cpp_user_defined_literals", "200809L");
604     Builder.defineMacro("__cpp_lambdas", "200907L");
605     Builder.defineMacro("__cpp_constexpr", LangOpts.CPlusPlus2b   ? "202110L"
606                                            : LangOpts.CPlusPlus20 ? "201907L"
607                                            : LangOpts.CPlusPlus17 ? "201603L"
608                                            : LangOpts.CPlusPlus14 ? "201304L"
609                                                                   : "200704");
610     Builder.defineMacro("__cpp_constexpr_in_decltype", "201711L");
611     Builder.defineMacro("__cpp_range_based_for",
612                         LangOpts.CPlusPlus17 ? "201603L" : "200907");
613     Builder.defineMacro("__cpp_static_assert",
614                         LangOpts.CPlusPlus17 ? "201411L" : "200410");
615     Builder.defineMacro("__cpp_decltype", "200707L");
616     Builder.defineMacro("__cpp_attributes", "200809L");
617     Builder.defineMacro("__cpp_rvalue_references", "200610L");
618     Builder.defineMacro("__cpp_variadic_templates", "200704L");
619     Builder.defineMacro("__cpp_initializer_lists", "200806L");
620     Builder.defineMacro("__cpp_delegating_constructors", "200604L");
621     Builder.defineMacro("__cpp_nsdmi", "200809L");
622     Builder.defineMacro("__cpp_inheriting_constructors", "201511L");
623     Builder.defineMacro("__cpp_ref_qualifiers", "200710L");
624     Builder.defineMacro("__cpp_alias_templates", "200704L");
625   }
626   if (LangOpts.ThreadsafeStatics)
627     Builder.defineMacro("__cpp_threadsafe_static_init", "200806L");
628 
629   // C++14 features.
630   if (LangOpts.CPlusPlus14) {
631     Builder.defineMacro("__cpp_binary_literals", "201304L");
632     Builder.defineMacro("__cpp_digit_separators", "201309L");
633     Builder.defineMacro("__cpp_init_captures",
634                         LangOpts.CPlusPlus20 ? "201803L" : "201304L");
635     Builder.defineMacro("__cpp_generic_lambdas",
636                         LangOpts.CPlusPlus20 ? "201707L" : "201304L");
637     Builder.defineMacro("__cpp_decltype_auto", "201304L");
638     Builder.defineMacro("__cpp_return_type_deduction", "201304L");
639     Builder.defineMacro("__cpp_aggregate_nsdmi", "201304L");
640     Builder.defineMacro("__cpp_variable_templates", "201304L");
641   }
642   if (LangOpts.SizedDeallocation)
643     Builder.defineMacro("__cpp_sized_deallocation", "201309L");
644 
645   // C++17 features.
646   if (LangOpts.CPlusPlus17) {
647     Builder.defineMacro("__cpp_hex_float", "201603L");
648     Builder.defineMacro("__cpp_inline_variables", "201606L");
649     Builder.defineMacro("__cpp_noexcept_function_type", "201510L");
650     Builder.defineMacro("__cpp_capture_star_this", "201603L");
651     Builder.defineMacro("__cpp_if_constexpr", "201606L");
652     Builder.defineMacro("__cpp_deduction_guides", "201703L"); // (not latest)
653     Builder.defineMacro("__cpp_template_auto", "201606L"); // (old name)
654     Builder.defineMacro("__cpp_namespace_attributes", "201411L");
655     Builder.defineMacro("__cpp_enumerator_attributes", "201411L");
656     Builder.defineMacro("__cpp_nested_namespace_definitions", "201411L");
657     Builder.defineMacro("__cpp_variadic_using", "201611L");
658     Builder.defineMacro("__cpp_aggregate_bases", "201603L");
659     Builder.defineMacro("__cpp_structured_bindings", "201606L");
660     Builder.defineMacro("__cpp_nontype_template_args",
661                         "201411L"); // (not latest)
662     Builder.defineMacro("__cpp_fold_expressions", "201603L");
663     Builder.defineMacro("__cpp_guaranteed_copy_elision", "201606L");
664     Builder.defineMacro("__cpp_nontype_template_parameter_auto", "201606L");
665   }
666   if (LangOpts.AlignedAllocation && !LangOpts.AlignedAllocationUnavailable)
667     Builder.defineMacro("__cpp_aligned_new", "201606L");
668   if (LangOpts.RelaxedTemplateTemplateArgs)
669     Builder.defineMacro("__cpp_template_template_args", "201611L");
670 
671   // C++20 features.
672   if (LangOpts.CPlusPlus20) {
673     //Builder.defineMacro("__cpp_aggregate_paren_init", "201902L");
674     Builder.defineMacro("__cpp_concepts", "201907L");
675     Builder.defineMacro("__cpp_conditional_explicit", "201806L");
676     //Builder.defineMacro("__cpp_consteval", "201811L");
677     Builder.defineMacro("__cpp_constexpr_dynamic_alloc", "201907L");
678     Builder.defineMacro("__cpp_constinit", "201907L");
679     Builder.defineMacro("__cpp_impl_coroutine", "201902L");
680     Builder.defineMacro("__cpp_designated_initializers", "201707L");
681     Builder.defineMacro("__cpp_impl_three_way_comparison", "201907L");
682     //Builder.defineMacro("__cpp_modules", "201907L");
683     Builder.defineMacro("__cpp_using_enum", "201907L");
684   }
685   // C++2b features.
686   if (LangOpts.CPlusPlus2b) {
687     Builder.defineMacro("__cpp_implicit_move", "202011L");
688     Builder.defineMacro("__cpp_size_t_suffix", "202011L");
689     Builder.defineMacro("__cpp_if_consteval", "202106L");
690     Builder.defineMacro("__cpp_­multidimensional_­subscript", "202110L");
691   }
692   if (LangOpts.Char8)
693     Builder.defineMacro("__cpp_char8_t", "201811L");
694   Builder.defineMacro("__cpp_impl_destroying_delete", "201806L");
695 
696   // TS features.
697   if (LangOpts.Coroutines)
698     Builder.defineMacro("__cpp_coroutines", "201703L");
699 }
700 
701 /// InitializeOpenCLFeatureTestMacros - Define OpenCL macros based on target
702 /// settings and language version
703 void InitializeOpenCLFeatureTestMacros(const TargetInfo &TI,
704                                        const LangOptions &Opts,
705                                        MacroBuilder &Builder) {
706   const llvm::StringMap<bool> &OpenCLFeaturesMap = TI.getSupportedOpenCLOpts();
707   // FIXME: OpenCL options which affect language semantics/syntax
708   // should be moved into LangOptions.
709   auto defineOpenCLExtMacro = [&](llvm::StringRef Name, auto... OptArgs) {
710     // Check if extension is supported by target and is available in this
711     // OpenCL version
712     if (TI.hasFeatureEnabled(OpenCLFeaturesMap, Name) &&
713         OpenCLOptions::isOpenCLOptionAvailableIn(Opts, OptArgs...))
714       Builder.defineMacro(Name);
715   };
716 #define OPENCL_GENERIC_EXTENSION(Ext, ...)                                     \
717   defineOpenCLExtMacro(#Ext, __VA_ARGS__);
718 #include "clang/Basic/OpenCLExtensions.def"
719 
720   // Assume compiling for FULL profile
721   Builder.defineMacro("__opencl_c_int64");
722 }
723 
724 static void InitializePredefinedMacros(const TargetInfo &TI,
725                                        const LangOptions &LangOpts,
726                                        const FrontendOptions &FEOpts,
727                                        const PreprocessorOptions &PPOpts,
728                                        MacroBuilder &Builder) {
729   // Compiler version introspection macros.
730   Builder.defineMacro("__llvm__");  // LLVM Backend
731   Builder.defineMacro("__clang__"); // Clang Frontend
732 #define TOSTR2(X) #X
733 #define TOSTR(X) TOSTR2(X)
734   Builder.defineMacro("__clang_major__", TOSTR(CLANG_VERSION_MAJOR));
735   Builder.defineMacro("__clang_minor__", TOSTR(CLANG_VERSION_MINOR));
736   Builder.defineMacro("__clang_patchlevel__", TOSTR(CLANG_VERSION_PATCHLEVEL));
737 #undef TOSTR
738 #undef TOSTR2
739   Builder.defineMacro("__clang_version__",
740                       "\"" CLANG_VERSION_STRING " "
741                       + getClangFullRepositoryVersion() + "\"");
742 
743   if (LangOpts.GNUCVersion != 0) {
744     // Major, minor, patch, are given two decimal places each, so 4.2.1 becomes
745     // 40201.
746     unsigned GNUCMajor = LangOpts.GNUCVersion / 100 / 100;
747     unsigned GNUCMinor = LangOpts.GNUCVersion / 100 % 100;
748     unsigned GNUCPatch = LangOpts.GNUCVersion % 100;
749     Builder.defineMacro("__GNUC__", Twine(GNUCMajor));
750     Builder.defineMacro("__GNUC_MINOR__", Twine(GNUCMinor));
751     Builder.defineMacro("__GNUC_PATCHLEVEL__", Twine(GNUCPatch));
752     Builder.defineMacro("__GXX_ABI_VERSION", "1002");
753 
754     if (LangOpts.CPlusPlus) {
755       Builder.defineMacro("__GNUG__", Twine(GNUCMajor));
756       Builder.defineMacro("__GXX_WEAK__");
757     }
758   }
759 
760   // Define macros for the C11 / C++11 memory orderings
761   Builder.defineMacro("__ATOMIC_RELAXED", "0");
762   Builder.defineMacro("__ATOMIC_CONSUME", "1");
763   Builder.defineMacro("__ATOMIC_ACQUIRE", "2");
764   Builder.defineMacro("__ATOMIC_RELEASE", "3");
765   Builder.defineMacro("__ATOMIC_ACQ_REL", "4");
766   Builder.defineMacro("__ATOMIC_SEQ_CST", "5");
767 
768   // Define macros for the OpenCL memory scope.
769   // The values should match AtomicScopeOpenCLModel::ID enum.
770   static_assert(
771       static_cast<unsigned>(AtomicScopeOpenCLModel::WorkGroup) == 1 &&
772           static_cast<unsigned>(AtomicScopeOpenCLModel::Device) == 2 &&
773           static_cast<unsigned>(AtomicScopeOpenCLModel::AllSVMDevices) == 3 &&
774           static_cast<unsigned>(AtomicScopeOpenCLModel::SubGroup) == 4,
775       "Invalid OpenCL memory scope enum definition");
776   Builder.defineMacro("__OPENCL_MEMORY_SCOPE_WORK_ITEM", "0");
777   Builder.defineMacro("__OPENCL_MEMORY_SCOPE_WORK_GROUP", "1");
778   Builder.defineMacro("__OPENCL_MEMORY_SCOPE_DEVICE", "2");
779   Builder.defineMacro("__OPENCL_MEMORY_SCOPE_ALL_SVM_DEVICES", "3");
780   Builder.defineMacro("__OPENCL_MEMORY_SCOPE_SUB_GROUP", "4");
781 
782   // Support for #pragma redefine_extname (Sun compatibility)
783   Builder.defineMacro("__PRAGMA_REDEFINE_EXTNAME", "1");
784 
785   // Previously this macro was set to a string aiming to achieve compatibility
786   // with GCC 4.2.1. Now, just return the full Clang version
787   Builder.defineMacro("__VERSION__", "\"" +
788                       Twine(getClangFullCPPVersion()) + "\"");
789 
790   // Initialize language-specific preprocessor defines.
791 
792   // Standard conforming mode?
793   if (!LangOpts.GNUMode && !LangOpts.MSVCCompat)
794     Builder.defineMacro("__STRICT_ANSI__");
795 
796   if (LangOpts.GNUCVersion && LangOpts.CPlusPlus11)
797     Builder.defineMacro("__GXX_EXPERIMENTAL_CXX0X__");
798 
799   if (LangOpts.ObjC) {
800     if (LangOpts.ObjCRuntime.isNonFragile()) {
801       Builder.defineMacro("__OBJC2__");
802 
803       if (LangOpts.ObjCExceptions)
804         Builder.defineMacro("OBJC_ZEROCOST_EXCEPTIONS");
805     }
806 
807     if (LangOpts.getGC() != LangOptions::NonGC)
808       Builder.defineMacro("__OBJC_GC__");
809 
810     if (LangOpts.ObjCRuntime.isNeXTFamily())
811       Builder.defineMacro("__NEXT_RUNTIME__");
812 
813     if (LangOpts.ObjCRuntime.getKind() == ObjCRuntime::GNUstep) {
814       auto version = LangOpts.ObjCRuntime.getVersion();
815       std::string versionString = "1";
816       // Don't rely on the tuple argument, because we can be asked to target
817       // later ABIs than we actually support, so clamp these values to those
818       // currently supported
819       if (version >= VersionTuple(2, 0))
820         Builder.defineMacro("__OBJC_GNUSTEP_RUNTIME_ABI__", "20");
821       else
822         Builder.defineMacro("__OBJC_GNUSTEP_RUNTIME_ABI__",
823             "1" + Twine(std::min(8U, version.getMinor().getValueOr(0))));
824     }
825 
826     if (LangOpts.ObjCRuntime.getKind() == ObjCRuntime::ObjFW) {
827       VersionTuple tuple = LangOpts.ObjCRuntime.getVersion();
828 
829       unsigned minor = 0;
830       if (tuple.getMinor().hasValue())
831         minor = tuple.getMinor().getValue();
832 
833       unsigned subminor = 0;
834       if (tuple.getSubminor().hasValue())
835         subminor = tuple.getSubminor().getValue();
836 
837       Builder.defineMacro("__OBJFW_RUNTIME_ABI__",
838                           Twine(tuple.getMajor() * 10000 + minor * 100 +
839                                 subminor));
840     }
841 
842     Builder.defineMacro("IBOutlet", "__attribute__((iboutlet))");
843     Builder.defineMacro("IBOutletCollection(ClassName)",
844                         "__attribute__((iboutletcollection(ClassName)))");
845     Builder.defineMacro("IBAction", "void)__attribute__((ibaction)");
846     Builder.defineMacro("IBInspectable", "");
847     Builder.defineMacro("IB_DESIGNABLE", "");
848   }
849 
850   // Define a macro that describes the Objective-C boolean type even for C
851   // and C++ since BOOL can be used from non Objective-C code.
852   Builder.defineMacro("__OBJC_BOOL_IS_BOOL",
853                       Twine(TI.useSignedCharForObjCBool() ? "0" : "1"));
854 
855   if (LangOpts.CPlusPlus)
856     InitializeCPlusPlusFeatureTestMacros(LangOpts, Builder);
857 
858   // darwin_constant_cfstrings controls this. This is also dependent
859   // on other things like the runtime I believe.  This is set even for C code.
860   if (!LangOpts.NoConstantCFStrings)
861       Builder.defineMacro("__CONSTANT_CFSTRINGS__");
862 
863   if (LangOpts.ObjC)
864     Builder.defineMacro("OBJC_NEW_PROPERTIES");
865 
866   if (LangOpts.PascalStrings)
867     Builder.defineMacro("__PASCAL_STRINGS__");
868 
869   if (LangOpts.Blocks) {
870     Builder.defineMacro("__block", "__attribute__((__blocks__(byref)))");
871     Builder.defineMacro("__BLOCKS__");
872   }
873 
874   if (!LangOpts.MSVCCompat && LangOpts.Exceptions)
875     Builder.defineMacro("__EXCEPTIONS");
876   if (LangOpts.GNUCVersion && LangOpts.RTTI)
877     Builder.defineMacro("__GXX_RTTI");
878 
879   if (LangOpts.hasSjLjExceptions())
880     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
881   else if (LangOpts.hasSEHExceptions())
882     Builder.defineMacro("__SEH__");
883   else if (LangOpts.hasDWARFExceptions() &&
884            (TI.getTriple().isThumb() || TI.getTriple().isARM()))
885     Builder.defineMacro("__ARM_DWARF_EH__");
886 
887   if (LangOpts.Deprecated)
888     Builder.defineMacro("__DEPRECATED");
889 
890   if (!LangOpts.MSVCCompat && LangOpts.CPlusPlus)
891     Builder.defineMacro("__private_extern__", "extern");
892 
893   if (LangOpts.MicrosoftExt) {
894     if (LangOpts.WChar) {
895       // wchar_t supported as a keyword.
896       Builder.defineMacro("_WCHAR_T_DEFINED");
897       Builder.defineMacro("_NATIVE_WCHAR_T_DEFINED");
898     }
899   }
900 
901   // Macros to help identify the narrow and wide character sets
902   // FIXME: clang currently ignores -fexec-charset=. If this changes,
903   // then this may need to be updated.
904   Builder.defineMacro("__clang_literal_encoding__", "\"UTF-8\"");
905   if (TI.getTypeWidth(TI.getWCharType()) >= 32) {
906     // FIXME: 32-bit wchar_t signals UTF-32. This may change
907     // if -fwide-exec-charset= is ever supported.
908     Builder.defineMacro("__clang_wide_literal_encoding__", "\"UTF-32\"");
909   } else {
910     // FIXME: Less-than 32-bit wchar_t generally means UTF-16
911     // (e.g., Windows, 32-bit IBM). This may need to be
912     // updated if -fwide-exec-charset= is ever supported.
913     Builder.defineMacro("__clang_wide_literal_encoding__", "\"UTF-16\"");
914   }
915 
916   if (LangOpts.Optimize)
917     Builder.defineMacro("__OPTIMIZE__");
918   if (LangOpts.OptimizeSize)
919     Builder.defineMacro("__OPTIMIZE_SIZE__");
920 
921   if (LangOpts.FastMath)
922     Builder.defineMacro("__FAST_MATH__");
923 
924   // Initialize target-specific preprocessor defines.
925 
926   // __BYTE_ORDER__ was added in GCC 4.6. It's analogous
927   // to the macro __BYTE_ORDER (no trailing underscores)
928   // from glibc's <endian.h> header.
929   // We don't support the PDP-11 as a target, but include
930   // the define so it can still be compared against.
931   Builder.defineMacro("__ORDER_LITTLE_ENDIAN__", "1234");
932   Builder.defineMacro("__ORDER_BIG_ENDIAN__",    "4321");
933   Builder.defineMacro("__ORDER_PDP_ENDIAN__",    "3412");
934   if (TI.isBigEndian()) {
935     Builder.defineMacro("__BYTE_ORDER__", "__ORDER_BIG_ENDIAN__");
936     Builder.defineMacro("__BIG_ENDIAN__");
937   } else {
938     Builder.defineMacro("__BYTE_ORDER__", "__ORDER_LITTLE_ENDIAN__");
939     Builder.defineMacro("__LITTLE_ENDIAN__");
940   }
941 
942   if (TI.getPointerWidth(0) == 64 && TI.getLongWidth() == 64
943       && TI.getIntWidth() == 32) {
944     Builder.defineMacro("_LP64");
945     Builder.defineMacro("__LP64__");
946   }
947 
948   if (TI.getPointerWidth(0) == 32 && TI.getLongWidth() == 32
949       && TI.getIntWidth() == 32) {
950     Builder.defineMacro("_ILP32");
951     Builder.defineMacro("__ILP32__");
952   }
953 
954   // Define type sizing macros based on the target properties.
955   assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
956   Builder.defineMacro("__CHAR_BIT__", Twine(TI.getCharWidth()));
957 
958   Builder.defineMacro("__BOOL_WIDTH__", Twine(TI.getBoolWidth()));
959   Builder.defineMacro("__SHRT_WIDTH__", Twine(TI.getShortWidth()));
960   Builder.defineMacro("__INT_WIDTH__", Twine(TI.getIntWidth()));
961   Builder.defineMacro("__LONG_WIDTH__", Twine(TI.getLongWidth()));
962   Builder.defineMacro("__LLONG_WIDTH__", Twine(TI.getLongLongWidth()));
963 
964   size_t BitIntMaxWidth = TI.getMaxBitIntWidth();
965   assert(BitIntMaxWidth <= llvm::IntegerType::MAX_INT_BITS &&
966          "Target defined a max bit width larger than LLVM can support!");
967   assert(BitIntMaxWidth >= TI.getLongLongWidth() &&
968          "Target defined a max bit width smaller than the C standard allows!");
969   Builder.defineMacro("__BITINT_MAXWIDTH__", Twine(BitIntMaxWidth));
970 
971   DefineTypeSize("__SCHAR_MAX__", TargetInfo::SignedChar, TI, Builder);
972   DefineTypeSize("__SHRT_MAX__", TargetInfo::SignedShort, TI, Builder);
973   DefineTypeSize("__INT_MAX__", TargetInfo::SignedInt, TI, Builder);
974   DefineTypeSize("__LONG_MAX__", TargetInfo::SignedLong, TI, Builder);
975   DefineTypeSize("__LONG_LONG_MAX__", TargetInfo::SignedLongLong, TI, Builder);
976   DefineTypeSizeAndWidth("__WCHAR", TI.getWCharType(), TI, Builder);
977   DefineTypeSizeAndWidth("__WINT", TI.getWIntType(), TI, Builder);
978   DefineTypeSizeAndWidth("__INTMAX", TI.getIntMaxType(), TI, Builder);
979   DefineTypeSizeAndWidth("__SIZE", TI.getSizeType(), TI, Builder);
980 
981   DefineTypeSizeAndWidth("__UINTMAX", TI.getUIntMaxType(), TI, Builder);
982   DefineTypeSizeAndWidth("__PTRDIFF", TI.getPtrDiffType(0), TI, Builder);
983   DefineTypeSizeAndWidth("__INTPTR", TI.getIntPtrType(), TI, Builder);
984   DefineTypeSizeAndWidth("__UINTPTR", TI.getUIntPtrType(), TI, Builder);
985 
986   DefineTypeSizeof("__SIZEOF_DOUBLE__", TI.getDoubleWidth(), TI, Builder);
987   DefineTypeSizeof("__SIZEOF_FLOAT__", TI.getFloatWidth(), TI, Builder);
988   DefineTypeSizeof("__SIZEOF_INT__", TI.getIntWidth(), TI, Builder);
989   DefineTypeSizeof("__SIZEOF_LONG__", TI.getLongWidth(), TI, Builder);
990   DefineTypeSizeof("__SIZEOF_LONG_DOUBLE__",TI.getLongDoubleWidth(),TI,Builder);
991   DefineTypeSizeof("__SIZEOF_LONG_LONG__", TI.getLongLongWidth(), TI, Builder);
992   DefineTypeSizeof("__SIZEOF_POINTER__", TI.getPointerWidth(0), TI, Builder);
993   DefineTypeSizeof("__SIZEOF_SHORT__", TI.getShortWidth(), TI, Builder);
994   DefineTypeSizeof("__SIZEOF_PTRDIFF_T__",
995                    TI.getTypeWidth(TI.getPtrDiffType(0)), TI, Builder);
996   DefineTypeSizeof("__SIZEOF_SIZE_T__",
997                    TI.getTypeWidth(TI.getSizeType()), TI, Builder);
998   DefineTypeSizeof("__SIZEOF_WCHAR_T__",
999                    TI.getTypeWidth(TI.getWCharType()), TI, Builder);
1000   DefineTypeSizeof("__SIZEOF_WINT_T__",
1001                    TI.getTypeWidth(TI.getWIntType()), TI, Builder);
1002   if (TI.hasInt128Type())
1003     DefineTypeSizeof("__SIZEOF_INT128__", 128, TI, Builder);
1004 
1005   DefineType("__INTMAX_TYPE__", TI.getIntMaxType(), Builder);
1006   DefineFmt("__INTMAX", TI.getIntMaxType(), TI, Builder);
1007   Builder.defineMacro("__INTMAX_C_SUFFIX__",
1008                       TI.getTypeConstantSuffix(TI.getIntMaxType()));
1009   DefineType("__UINTMAX_TYPE__", TI.getUIntMaxType(), Builder);
1010   DefineFmt("__UINTMAX", TI.getUIntMaxType(), TI, Builder);
1011   Builder.defineMacro("__UINTMAX_C_SUFFIX__",
1012                       TI.getTypeConstantSuffix(TI.getUIntMaxType()));
1013   DefineType("__PTRDIFF_TYPE__", TI.getPtrDiffType(0), Builder);
1014   DefineFmt("__PTRDIFF", TI.getPtrDiffType(0), TI, Builder);
1015   DefineType("__INTPTR_TYPE__", TI.getIntPtrType(), Builder);
1016   DefineFmt("__INTPTR", TI.getIntPtrType(), TI, Builder);
1017   DefineType("__SIZE_TYPE__", TI.getSizeType(), Builder);
1018   DefineFmt("__SIZE", TI.getSizeType(), TI, Builder);
1019   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Builder);
1020   DefineType("__WINT_TYPE__", TI.getWIntType(), Builder);
1021   DefineTypeSizeAndWidth("__SIG_ATOMIC", TI.getSigAtomicType(), TI, Builder);
1022   DefineType("__CHAR16_TYPE__", TI.getChar16Type(), Builder);
1023   DefineType("__CHAR32_TYPE__", TI.getChar32Type(), Builder);
1024 
1025   DefineType("__UINTPTR_TYPE__", TI.getUIntPtrType(), Builder);
1026   DefineFmt("__UINTPTR", TI.getUIntPtrType(), TI, Builder);
1027 
1028   // The C standard requires the width of uintptr_t and intptr_t to be the same,
1029   // per 7.20.2.4p1. Same for intmax_t and uintmax_t, per 7.20.2.5p1.
1030   assert(TI.getTypeWidth(TI.getUIntPtrType()) ==
1031              TI.getTypeWidth(TI.getIntPtrType()) &&
1032          "uintptr_t and intptr_t have different widths?");
1033   assert(TI.getTypeWidth(TI.getUIntMaxType()) ==
1034              TI.getTypeWidth(TI.getIntMaxType()) &&
1035          "uintmax_t and intmax_t have different widths?");
1036 
1037   if (TI.hasFloat16Type())
1038     DefineFloatMacros(Builder, "FLT16", &TI.getHalfFormat(), "F16");
1039   DefineFloatMacros(Builder, "FLT", &TI.getFloatFormat(), "F");
1040   DefineFloatMacros(Builder, "DBL", &TI.getDoubleFormat(), "");
1041   DefineFloatMacros(Builder, "LDBL", &TI.getLongDoubleFormat(), "L");
1042 
1043   // Define a __POINTER_WIDTH__ macro for stdint.h.
1044   Builder.defineMacro("__POINTER_WIDTH__",
1045                       Twine((int)TI.getPointerWidth(0)));
1046 
1047   // Define __BIGGEST_ALIGNMENT__ to be compatible with gcc.
1048   Builder.defineMacro("__BIGGEST_ALIGNMENT__",
1049                       Twine(TI.getSuitableAlign() / TI.getCharWidth()) );
1050 
1051   if (!LangOpts.CharIsSigned)
1052     Builder.defineMacro("__CHAR_UNSIGNED__");
1053 
1054   if (!TargetInfo::isTypeSigned(TI.getWCharType()))
1055     Builder.defineMacro("__WCHAR_UNSIGNED__");
1056 
1057   if (!TargetInfo::isTypeSigned(TI.getWIntType()))
1058     Builder.defineMacro("__WINT_UNSIGNED__");
1059 
1060   // Define exact-width integer types for stdint.h
1061   DefineExactWidthIntType(TargetInfo::SignedChar, TI, Builder);
1062 
1063   if (TI.getShortWidth() > TI.getCharWidth())
1064     DefineExactWidthIntType(TargetInfo::SignedShort, TI, Builder);
1065 
1066   if (TI.getIntWidth() > TI.getShortWidth())
1067     DefineExactWidthIntType(TargetInfo::SignedInt, TI, Builder);
1068 
1069   if (TI.getLongWidth() > TI.getIntWidth())
1070     DefineExactWidthIntType(TargetInfo::SignedLong, TI, Builder);
1071 
1072   if (TI.getLongLongWidth() > TI.getLongWidth())
1073     DefineExactWidthIntType(TargetInfo::SignedLongLong, TI, Builder);
1074 
1075   DefineExactWidthIntType(TargetInfo::UnsignedChar, TI, Builder);
1076   DefineExactWidthIntTypeSize(TargetInfo::UnsignedChar, TI, Builder);
1077   DefineExactWidthIntTypeSize(TargetInfo::SignedChar, TI, Builder);
1078 
1079   if (TI.getShortWidth() > TI.getCharWidth()) {
1080     DefineExactWidthIntType(TargetInfo::UnsignedShort, TI, Builder);
1081     DefineExactWidthIntTypeSize(TargetInfo::UnsignedShort, TI, Builder);
1082     DefineExactWidthIntTypeSize(TargetInfo::SignedShort, TI, Builder);
1083   }
1084 
1085   if (TI.getIntWidth() > TI.getShortWidth()) {
1086     DefineExactWidthIntType(TargetInfo::UnsignedInt, TI, Builder);
1087     DefineExactWidthIntTypeSize(TargetInfo::UnsignedInt, TI, Builder);
1088     DefineExactWidthIntTypeSize(TargetInfo::SignedInt, TI, Builder);
1089   }
1090 
1091   if (TI.getLongWidth() > TI.getIntWidth()) {
1092     DefineExactWidthIntType(TargetInfo::UnsignedLong, TI, Builder);
1093     DefineExactWidthIntTypeSize(TargetInfo::UnsignedLong, TI, Builder);
1094     DefineExactWidthIntTypeSize(TargetInfo::SignedLong, TI, Builder);
1095   }
1096 
1097   if (TI.getLongLongWidth() > TI.getLongWidth()) {
1098     DefineExactWidthIntType(TargetInfo::UnsignedLongLong, TI, Builder);
1099     DefineExactWidthIntTypeSize(TargetInfo::UnsignedLongLong, TI, Builder);
1100     DefineExactWidthIntTypeSize(TargetInfo::SignedLongLong, TI, Builder);
1101   }
1102 
1103   DefineLeastWidthIntType(8, true, TI, Builder);
1104   DefineLeastWidthIntType(8, false, TI, Builder);
1105   DefineLeastWidthIntType(16, true, TI, Builder);
1106   DefineLeastWidthIntType(16, false, TI, Builder);
1107   DefineLeastWidthIntType(32, true, TI, Builder);
1108   DefineLeastWidthIntType(32, false, TI, Builder);
1109   DefineLeastWidthIntType(64, true, TI, Builder);
1110   DefineLeastWidthIntType(64, false, TI, Builder);
1111 
1112   DefineFastIntType(8, true, TI, Builder);
1113   DefineFastIntType(8, false, TI, Builder);
1114   DefineFastIntType(16, true, TI, Builder);
1115   DefineFastIntType(16, false, TI, Builder);
1116   DefineFastIntType(32, true, TI, Builder);
1117   DefineFastIntType(32, false, TI, Builder);
1118   DefineFastIntType(64, true, TI, Builder);
1119   DefineFastIntType(64, false, TI, Builder);
1120 
1121   Builder.defineMacro("__USER_LABEL_PREFIX__", TI.getUserLabelPrefix());
1122 
1123   if (!LangOpts.MathErrno)
1124     Builder.defineMacro("__NO_MATH_ERRNO__");
1125 
1126   if (LangOpts.FastMath || LangOpts.FiniteMathOnly)
1127     Builder.defineMacro("__FINITE_MATH_ONLY__", "1");
1128   else
1129     Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
1130 
1131   if (LangOpts.GNUCVersion) {
1132     if (LangOpts.GNUInline || LangOpts.CPlusPlus)
1133       Builder.defineMacro("__GNUC_GNU_INLINE__");
1134     else
1135       Builder.defineMacro("__GNUC_STDC_INLINE__");
1136 
1137     // The value written by __atomic_test_and_set.
1138     // FIXME: This is target-dependent.
1139     Builder.defineMacro("__GCC_ATOMIC_TEST_AND_SET_TRUEVAL", "1");
1140   }
1141 
1142   auto addLockFreeMacros = [&](const llvm::Twine &Prefix) {
1143     // Used by libc++ and libstdc++ to implement ATOMIC_<foo>_LOCK_FREE.
1144     unsigned InlineWidthBits = TI.getMaxAtomicInlineWidth();
1145 #define DEFINE_LOCK_FREE_MACRO(TYPE, Type)                                     \
1146   Builder.defineMacro(Prefix + #TYPE "_LOCK_FREE",                             \
1147                       getLockFreeValue(TI.get##Type##Width(),                  \
1148                                        TI.get##Type##Align(),                  \
1149                                        InlineWidthBits));
1150     DEFINE_LOCK_FREE_MACRO(BOOL, Bool);
1151     DEFINE_LOCK_FREE_MACRO(CHAR, Char);
1152     if (LangOpts.Char8)
1153       DEFINE_LOCK_FREE_MACRO(CHAR8_T, Char); // Treat char8_t like char.
1154     DEFINE_LOCK_FREE_MACRO(CHAR16_T, Char16);
1155     DEFINE_LOCK_FREE_MACRO(CHAR32_T, Char32);
1156     DEFINE_LOCK_FREE_MACRO(WCHAR_T, WChar);
1157     DEFINE_LOCK_FREE_MACRO(SHORT, Short);
1158     DEFINE_LOCK_FREE_MACRO(INT, Int);
1159     DEFINE_LOCK_FREE_MACRO(LONG, Long);
1160     DEFINE_LOCK_FREE_MACRO(LLONG, LongLong);
1161     Builder.defineMacro(Prefix + "POINTER_LOCK_FREE",
1162                         getLockFreeValue(TI.getPointerWidth(0),
1163                                          TI.getPointerAlign(0),
1164                                          InlineWidthBits));
1165 #undef DEFINE_LOCK_FREE_MACRO
1166   };
1167   addLockFreeMacros("__CLANG_ATOMIC_");
1168   if (LangOpts.GNUCVersion)
1169     addLockFreeMacros("__GCC_ATOMIC_");
1170 
1171   if (LangOpts.NoInlineDefine)
1172     Builder.defineMacro("__NO_INLINE__");
1173 
1174   if (unsigned PICLevel = LangOpts.PICLevel) {
1175     Builder.defineMacro("__PIC__", Twine(PICLevel));
1176     Builder.defineMacro("__pic__", Twine(PICLevel));
1177     if (LangOpts.PIE) {
1178       Builder.defineMacro("__PIE__", Twine(PICLevel));
1179       Builder.defineMacro("__pie__", Twine(PICLevel));
1180     }
1181   }
1182 
1183   // Macros to control C99 numerics and <float.h>
1184   Builder.defineMacro("__FLT_RADIX__", "2");
1185   Builder.defineMacro("__DECIMAL_DIG__", "__LDBL_DECIMAL_DIG__");
1186 
1187   if (LangOpts.getStackProtector() == LangOptions::SSPOn)
1188     Builder.defineMacro("__SSP__");
1189   else if (LangOpts.getStackProtector() == LangOptions::SSPStrong)
1190     Builder.defineMacro("__SSP_STRONG__", "2");
1191   else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
1192     Builder.defineMacro("__SSP_ALL__", "3");
1193 
1194   if (PPOpts.SetUpStaticAnalyzer)
1195     Builder.defineMacro("__clang_analyzer__");
1196 
1197   if (LangOpts.FastRelaxedMath)
1198     Builder.defineMacro("__FAST_RELAXED_MATH__");
1199 
1200   if (FEOpts.ProgramAction == frontend::RewriteObjC ||
1201       LangOpts.getGC() != LangOptions::NonGC) {
1202     Builder.defineMacro("__weak", "__attribute__((objc_gc(weak)))");
1203     Builder.defineMacro("__strong", "__attribute__((objc_gc(strong)))");
1204     Builder.defineMacro("__autoreleasing", "");
1205     Builder.defineMacro("__unsafe_unretained", "");
1206   } else if (LangOpts.ObjC) {
1207     Builder.defineMacro("__weak", "__attribute__((objc_ownership(weak)))");
1208     Builder.defineMacro("__strong", "__attribute__((objc_ownership(strong)))");
1209     Builder.defineMacro("__autoreleasing",
1210                         "__attribute__((objc_ownership(autoreleasing)))");
1211     Builder.defineMacro("__unsafe_unretained",
1212                         "__attribute__((objc_ownership(none)))");
1213   }
1214 
1215   // On Darwin, there are __double_underscored variants of the type
1216   // nullability qualifiers.
1217   if (TI.getTriple().isOSDarwin()) {
1218     Builder.defineMacro("__nonnull", "_Nonnull");
1219     Builder.defineMacro("__null_unspecified", "_Null_unspecified");
1220     Builder.defineMacro("__nullable", "_Nullable");
1221   }
1222 
1223   // Add a macro to differentiate between regular iOS/tvOS/watchOS targets and
1224   // the corresponding simulator targets.
1225   if (TI.getTriple().isOSDarwin() && TI.getTriple().isSimulatorEnvironment())
1226     Builder.defineMacro("__APPLE_EMBEDDED_SIMULATOR__", "1");
1227 
1228   // OpenMP definition
1229   // OpenMP 2.2:
1230   //   In implementations that support a preprocessor, the _OPENMP
1231   //   macro name is defined to have the decimal value yyyymm where
1232   //   yyyy and mm are the year and the month designations of the
1233   //   version of the OpenMP API that the implementation support.
1234   if (!LangOpts.OpenMPSimd) {
1235     switch (LangOpts.OpenMP) {
1236     case 0:
1237       break;
1238     case 31:
1239       Builder.defineMacro("_OPENMP", "201107");
1240       break;
1241     case 40:
1242       Builder.defineMacro("_OPENMP", "201307");
1243       break;
1244     case 45:
1245       Builder.defineMacro("_OPENMP", "201511");
1246       break;
1247     case 51:
1248       Builder.defineMacro("_OPENMP", "202011");
1249       break;
1250     case 52:
1251       Builder.defineMacro("_OPENMP", "202111");
1252       break;
1253     default:
1254       // Default version is OpenMP 5.0
1255       Builder.defineMacro("_OPENMP", "201811");
1256       break;
1257     }
1258   }
1259 
1260   // CUDA device path compilaton
1261   if (LangOpts.CUDAIsDevice && !LangOpts.HIP) {
1262     // The CUDA_ARCH value is set for the GPU target specified in the NVPTX
1263     // backend's target defines.
1264     Builder.defineMacro("__CUDA_ARCH__");
1265   }
1266 
1267   // We need to communicate this to our CUDA header wrapper, which in turn
1268   // informs the proper CUDA headers of this choice.
1269   if (LangOpts.CUDADeviceApproxTranscendentals || LangOpts.FastMath) {
1270     Builder.defineMacro("__CLANG_CUDA_APPROX_TRANSCENDENTALS__");
1271   }
1272 
1273   // Define a macro indicating that the source file is being compiled with a
1274   // SYCL device compiler which doesn't produce host binary.
1275   if (LangOpts.SYCLIsDevice) {
1276     Builder.defineMacro("__SYCL_DEVICE_ONLY__", "1");
1277   }
1278 
1279   // OpenCL definitions.
1280   if (LangOpts.OpenCL) {
1281     InitializeOpenCLFeatureTestMacros(TI, LangOpts, Builder);
1282 
1283     if (TI.getTriple().isSPIR() || TI.getTriple().isSPIRV())
1284       Builder.defineMacro("__IMAGE_SUPPORT__");
1285   }
1286 
1287   if (TI.hasInt128Type() && LangOpts.CPlusPlus && LangOpts.GNUMode) {
1288     // For each extended integer type, g++ defines a macro mapping the
1289     // index of the type (0 in this case) in some list of extended types
1290     // to the type.
1291     Builder.defineMacro("__GLIBCXX_TYPE_INT_N_0", "__int128");
1292     Builder.defineMacro("__GLIBCXX_BITSIZE_INT_N_0", "128");
1293   }
1294 
1295   // Get other target #defines.
1296   TI.getTargetDefines(LangOpts, Builder);
1297 }
1298 
1299 /// InitializePreprocessor - Initialize the preprocessor getting it and the
1300 /// environment ready to process a single file. This returns true on error.
1301 ///
1302 void clang::InitializePreprocessor(
1303     Preprocessor &PP, const PreprocessorOptions &InitOpts,
1304     const PCHContainerReader &PCHContainerRdr,
1305     const FrontendOptions &FEOpts) {
1306   const LangOptions &LangOpts = PP.getLangOpts();
1307   std::string PredefineBuffer;
1308   PredefineBuffer.reserve(4080);
1309   llvm::raw_string_ostream Predefines(PredefineBuffer);
1310   MacroBuilder Builder(Predefines);
1311 
1312   // Emit line markers for various builtin sections of the file.  We don't do
1313   // this in asm preprocessor mode, because "# 4" is not a line marker directive
1314   // in this mode.
1315   if (!PP.getLangOpts().AsmPreprocessor)
1316     Builder.append("# 1 \"<built-in>\" 3");
1317 
1318   // Install things like __POWERPC__, __GNUC__, etc into the macro table.
1319   if (InitOpts.UsePredefines) {
1320     // FIXME: This will create multiple definitions for most of the predefined
1321     // macros. This is not the right way to handle this.
1322     if ((LangOpts.CUDA || LangOpts.OpenMPIsDevice || LangOpts.SYCLIsDevice) &&
1323         PP.getAuxTargetInfo())
1324       InitializePredefinedMacros(*PP.getAuxTargetInfo(), LangOpts, FEOpts,
1325                                  PP.getPreprocessorOpts(), Builder);
1326 
1327     InitializePredefinedMacros(PP.getTargetInfo(), LangOpts, FEOpts,
1328                                PP.getPreprocessorOpts(), Builder);
1329 
1330     // Install definitions to make Objective-C++ ARC work well with various
1331     // C++ Standard Library implementations.
1332     if (LangOpts.ObjC && LangOpts.CPlusPlus &&
1333         (LangOpts.ObjCAutoRefCount || LangOpts.ObjCWeak)) {
1334       switch (InitOpts.ObjCXXARCStandardLibrary) {
1335       case ARCXX_nolib:
1336       case ARCXX_libcxx:
1337         break;
1338 
1339       case ARCXX_libstdcxx:
1340         AddObjCXXARCLibstdcxxDefines(LangOpts, Builder);
1341         break;
1342       }
1343     }
1344   }
1345 
1346   // Even with predefines off, some macros are still predefined.
1347   // These should all be defined in the preprocessor according to the
1348   // current language configuration.
1349   InitializeStandardPredefinedMacros(PP.getTargetInfo(), PP.getLangOpts(),
1350                                      FEOpts, Builder);
1351 
1352   // Add on the predefines from the driver.  Wrap in a #line directive to report
1353   // that they come from the command line.
1354   if (!PP.getLangOpts().AsmPreprocessor)
1355     Builder.append("# 1 \"<command line>\" 1");
1356 
1357   // Process #define's and #undef's in the order they are given.
1358   for (unsigned i = 0, e = InitOpts.Macros.size(); i != e; ++i) {
1359     if (InitOpts.Macros[i].second)  // isUndef
1360       Builder.undefineMacro(InitOpts.Macros[i].first);
1361     else
1362       DefineBuiltinMacro(Builder, InitOpts.Macros[i].first,
1363                          PP.getDiagnostics());
1364   }
1365 
1366   // Exit the command line and go back to <built-in> (2 is LC_LEAVE).
1367   if (!PP.getLangOpts().AsmPreprocessor)
1368     Builder.append("# 1 \"<built-in>\" 2");
1369 
1370   // If -imacros are specified, include them now.  These are processed before
1371   // any -include directives.
1372   for (unsigned i = 0, e = InitOpts.MacroIncludes.size(); i != e; ++i)
1373     AddImplicitIncludeMacros(Builder, InitOpts.MacroIncludes[i]);
1374 
1375   // Process -include-pch/-include-pth directives.
1376   if (!InitOpts.ImplicitPCHInclude.empty())
1377     AddImplicitIncludePCH(Builder, PP, PCHContainerRdr,
1378                           InitOpts.ImplicitPCHInclude);
1379 
1380   // Process -include directives.
1381   for (unsigned i = 0, e = InitOpts.Includes.size(); i != e; ++i) {
1382     const std::string &Path = InitOpts.Includes[i];
1383     AddImplicitInclude(Builder, Path);
1384   }
1385 
1386   // Instruct the preprocessor to skip the preamble.
1387   PP.setSkipMainFilePreamble(InitOpts.PrecompiledPreambleBytes.first,
1388                              InitOpts.PrecompiledPreambleBytes.second);
1389 
1390   // Copy PredefinedBuffer into the Preprocessor.
1391   PP.setPredefines(Predefines.str());
1392 }
1393