xref: /freebsd/contrib/llvm-project/llvm/lib/CodeGen/CommandFlags.cpp (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 //===-- CommandFlags.cpp - Command Line Flags Interface ---------*- 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 contains codegen-specific flags that are shared between different
10 // command line tools. The tools "llc" and "opt" both use this file to prevent
11 // flag duplication.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/CodeGen/CommandFlags.h"
16 #include "llvm/IR/Module.h"
17 #include "llvm/MC/SubtargetFeature.h"
18 #include "llvm/Support/CommandLine.h"
19 #include "llvm/Support/Host.h"
20 
21 using namespace llvm;
22 
23 #define CGOPT(TY, NAME)                                                        \
24   static cl::opt<TY> *NAME##View;                                              \
25   TY codegen::get##NAME() {                                                    \
26     assert(NAME##View && "RegisterCodeGenFlags not created.");                 \
27     return *NAME##View;                                                        \
28   }
29 
30 #define CGLIST(TY, NAME)                                                       \
31   static cl::list<TY> *NAME##View;                                             \
32   std::vector<TY> codegen::get##NAME() {                                       \
33     assert(NAME##View && "RegisterCodeGenFlags not created.");                 \
34     return *NAME##View;                                                        \
35   }
36 
37 #define CGOPT_EXP(TY, NAME)                                                    \
38   CGOPT(TY, NAME)                                                              \
39   Optional<TY> codegen::getExplicit##NAME() {                                  \
40     if (NAME##View->getNumOccurrences()) {                                     \
41       TY res = *NAME##View;                                                    \
42       return res;                                                              \
43     }                                                                          \
44     return None;                                                               \
45   }
46 
47 CGOPT(std::string, MArch)
48 CGOPT(std::string, MCPU)
49 CGLIST(std::string, MAttrs)
50 CGOPT_EXP(Reloc::Model, RelocModel)
51 CGOPT(ThreadModel::Model, ThreadModel)
52 CGOPT_EXP(CodeModel::Model, CodeModel)
53 CGOPT(ExceptionHandling, ExceptionModel)
54 CGOPT_EXP(CodeGenFileType, FileType)
55 CGOPT(FramePointer::FP, FramePointerUsage)
56 CGOPT(bool, EnableUnsafeFPMath)
57 CGOPT(bool, EnableNoInfsFPMath)
58 CGOPT(bool, EnableNoNaNsFPMath)
59 CGOPT(bool, EnableNoSignedZerosFPMath)
60 CGOPT(bool, EnableNoTrappingFPMath)
61 CGOPT(DenormalMode::DenormalModeKind, DenormalFPMath)
62 CGOPT(DenormalMode::DenormalModeKind, DenormalFP32Math)
63 CGOPT(bool, EnableHonorSignDependentRoundingFPMath)
64 CGOPT(FloatABI::ABIType, FloatABIForCalls)
65 CGOPT(FPOpFusion::FPOpFusionMode, FuseFPOps)
66 CGOPT(bool, DontPlaceZerosInBSS)
67 CGOPT(bool, EnableGuaranteedTailCallOpt)
68 CGOPT(bool, DisableTailCalls)
69 CGOPT(bool, StackSymbolOrdering)
70 CGOPT(unsigned, OverrideStackAlignment)
71 CGOPT(bool, StackRealign)
72 CGOPT(std::string, TrapFuncName)
73 CGOPT(bool, UseCtors)
74 CGOPT(bool, RelaxELFRelocations)
75 CGOPT_EXP(bool, DataSections)
76 CGOPT_EXP(bool, FunctionSections)
77 CGOPT(std::string, BBSections)
78 CGOPT(unsigned, TLSSize)
79 CGOPT(bool, EmulatedTLS)
80 CGOPT(bool, UniqueSectionNames)
81 CGOPT(bool, UniqueBasicBlockSectionNames)
82 CGOPT(EABI, EABIVersion)
83 CGOPT(DebuggerKind, DebuggerTuningOpt)
84 CGOPT(bool, EnableStackSizeSection)
85 CGOPT(bool, EnableAddrsig)
86 CGOPT(bool, EmitCallSiteInfo)
87 CGOPT(bool, EnableDebugEntryValues)
88 CGOPT(bool, ForceDwarfFrameSection)
89 CGOPT(bool, XRayOmitFunctionIndex)
90 
91 codegen::RegisterCodeGenFlags::RegisterCodeGenFlags() {
92 #define CGBINDOPT(NAME)                                                        \
93   do {                                                                         \
94     NAME##View = std::addressof(NAME);                                         \
95   } while (0)
96 
97   static cl::opt<std::string> MArch(
98       "march", cl::desc("Architecture to generate code for (see --version)"));
99   CGBINDOPT(MArch);
100 
101   static cl::opt<std::string> MCPU(
102       "mcpu", cl::desc("Target a specific cpu type (-mcpu=help for details)"),
103       cl::value_desc("cpu-name"), cl::init(""));
104   CGBINDOPT(MCPU);
105 
106   static cl::list<std::string> MAttrs(
107       "mattr", cl::CommaSeparated,
108       cl::desc("Target specific attributes (-mattr=help for details)"),
109       cl::value_desc("a1,+a2,-a3,..."));
110   CGBINDOPT(MAttrs);
111 
112   static cl::opt<Reloc::Model> RelocModel(
113       "relocation-model", cl::desc("Choose relocation model"),
114       cl::values(
115           clEnumValN(Reloc::Static, "static", "Non-relocatable code"),
116           clEnumValN(Reloc::PIC_, "pic",
117                      "Fully relocatable, position independent code"),
118           clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
119                      "Relocatable external references, non-relocatable code"),
120           clEnumValN(
121               Reloc::ROPI, "ropi",
122               "Code and read-only data relocatable, accessed PC-relative"),
123           clEnumValN(
124               Reloc::RWPI, "rwpi",
125               "Read-write data relocatable, accessed relative to static base"),
126           clEnumValN(Reloc::ROPI_RWPI, "ropi-rwpi",
127                      "Combination of ropi and rwpi")));
128   CGBINDOPT(RelocModel);
129 
130   static cl::opt<ThreadModel::Model> ThreadModel(
131       "thread-model", cl::desc("Choose threading model"),
132       cl::init(ThreadModel::POSIX),
133       cl::values(
134           clEnumValN(ThreadModel::POSIX, "posix", "POSIX thread model"),
135           clEnumValN(ThreadModel::Single, "single", "Single thread model")));
136   CGBINDOPT(ThreadModel);
137 
138   static cl::opt<CodeModel::Model> CodeModel(
139       "code-model", cl::desc("Choose code model"),
140       cl::values(clEnumValN(CodeModel::Tiny, "tiny", "Tiny code model"),
141                  clEnumValN(CodeModel::Small, "small", "Small code model"),
142                  clEnumValN(CodeModel::Kernel, "kernel", "Kernel code model"),
143                  clEnumValN(CodeModel::Medium, "medium", "Medium code model"),
144                  clEnumValN(CodeModel::Large, "large", "Large code model")));
145   CGBINDOPT(CodeModel);
146 
147   static cl::opt<ExceptionHandling> ExceptionModel(
148       "exception-model", cl::desc("exception model"),
149       cl::init(ExceptionHandling::None),
150       cl::values(
151           clEnumValN(ExceptionHandling::None, "default",
152                      "default exception handling model"),
153           clEnumValN(ExceptionHandling::DwarfCFI, "dwarf",
154                      "DWARF-like CFI based exception handling"),
155           clEnumValN(ExceptionHandling::SjLj, "sjlj",
156                      "SjLj exception handling"),
157           clEnumValN(ExceptionHandling::ARM, "arm", "ARM EHABI exceptions"),
158           clEnumValN(ExceptionHandling::WinEH, "wineh",
159                      "Windows exception model"),
160           clEnumValN(ExceptionHandling::Wasm, "wasm",
161                      "WebAssembly exception handling")));
162   CGBINDOPT(ExceptionModel);
163 
164   static cl::opt<CodeGenFileType> FileType(
165       "filetype", cl::init(CGFT_AssemblyFile),
166       cl::desc(
167           "Choose a file type (not all types are supported by all targets):"),
168       cl::values(
169           clEnumValN(CGFT_AssemblyFile, "asm", "Emit an assembly ('.s') file"),
170           clEnumValN(CGFT_ObjectFile, "obj",
171                      "Emit a native object ('.o') file"),
172           clEnumValN(CGFT_Null, "null",
173                      "Emit nothing, for performance testing")));
174   CGBINDOPT(FileType);
175 
176   static cl::opt<FramePointer::FP> FramePointerUsage(
177       "frame-pointer",
178       cl::desc("Specify frame pointer elimination optimization"),
179       cl::init(FramePointer::None),
180       cl::values(
181           clEnumValN(FramePointer::All, "all",
182                      "Disable frame pointer elimination"),
183           clEnumValN(FramePointer::NonLeaf, "non-leaf",
184                      "Disable frame pointer elimination for non-leaf frame"),
185           clEnumValN(FramePointer::None, "none",
186                      "Enable frame pointer elimination")));
187   CGBINDOPT(FramePointerUsage);
188 
189   static cl::opt<bool> EnableUnsafeFPMath(
190       "enable-unsafe-fp-math",
191       cl::desc("Enable optimizations that may decrease FP precision"),
192       cl::init(false));
193   CGBINDOPT(EnableUnsafeFPMath);
194 
195   static cl::opt<bool> EnableNoInfsFPMath(
196       "enable-no-infs-fp-math",
197       cl::desc("Enable FP math optimizations that assume no +-Infs"),
198       cl::init(false));
199   CGBINDOPT(EnableNoInfsFPMath);
200 
201   static cl::opt<bool> EnableNoNaNsFPMath(
202       "enable-no-nans-fp-math",
203       cl::desc("Enable FP math optimizations that assume no NaNs"),
204       cl::init(false));
205   CGBINDOPT(EnableNoNaNsFPMath);
206 
207   static cl::opt<bool> EnableNoSignedZerosFPMath(
208       "enable-no-signed-zeros-fp-math",
209       cl::desc("Enable FP math optimizations that assume "
210                "the sign of 0 is insignificant"),
211       cl::init(false));
212   CGBINDOPT(EnableNoSignedZerosFPMath);
213 
214   static cl::opt<bool> EnableNoTrappingFPMath(
215       "enable-no-trapping-fp-math",
216       cl::desc("Enable setting the FP exceptions build "
217                "attribute not to use exceptions"),
218       cl::init(false));
219   CGBINDOPT(EnableNoTrappingFPMath);
220 
221   static const auto DenormFlagEnumOptions =
222   cl::values(clEnumValN(DenormalMode::IEEE, "ieee",
223                         "IEEE 754 denormal numbers"),
224              clEnumValN(DenormalMode::PreserveSign, "preserve-sign",
225                         "the sign of a  flushed-to-zero number is preserved "
226                         "in the sign of 0"),
227              clEnumValN(DenormalMode::PositiveZero, "positive-zero",
228                         "denormals are flushed to positive zero"));
229 
230   // FIXME: Doesn't have way to specify separate input and output modes.
231   static cl::opt<DenormalMode::DenormalModeKind> DenormalFPMath(
232     "denormal-fp-math",
233     cl::desc("Select which denormal numbers the code is permitted to require"),
234     cl::init(DenormalMode::IEEE),
235     DenormFlagEnumOptions);
236   CGBINDOPT(DenormalFPMath);
237 
238   static cl::opt<DenormalMode::DenormalModeKind> DenormalFP32Math(
239     "denormal-fp-math-f32",
240     cl::desc("Select which denormal numbers the code is permitted to require for float"),
241     cl::init(DenormalMode::Invalid),
242     DenormFlagEnumOptions);
243   CGBINDOPT(DenormalFP32Math);
244 
245   static cl::opt<bool> EnableHonorSignDependentRoundingFPMath(
246       "enable-sign-dependent-rounding-fp-math", cl::Hidden,
247       cl::desc("Force codegen to assume rounding mode can change dynamically"),
248       cl::init(false));
249   CGBINDOPT(EnableHonorSignDependentRoundingFPMath);
250 
251   static cl::opt<FloatABI::ABIType> FloatABIForCalls(
252       "float-abi", cl::desc("Choose float ABI type"),
253       cl::init(FloatABI::Default),
254       cl::values(clEnumValN(FloatABI::Default, "default",
255                             "Target default float ABI type"),
256                  clEnumValN(FloatABI::Soft, "soft",
257                             "Soft float ABI (implied by -soft-float)"),
258                  clEnumValN(FloatABI::Hard, "hard",
259                             "Hard float ABI (uses FP registers)")));
260   CGBINDOPT(FloatABIForCalls);
261 
262   static cl::opt<FPOpFusion::FPOpFusionMode> FuseFPOps(
263       "fp-contract", cl::desc("Enable aggressive formation of fused FP ops"),
264       cl::init(FPOpFusion::Standard),
265       cl::values(
266           clEnumValN(FPOpFusion::Fast, "fast",
267                      "Fuse FP ops whenever profitable"),
268           clEnumValN(FPOpFusion::Standard, "on", "Only fuse 'blessed' FP ops."),
269           clEnumValN(FPOpFusion::Strict, "off",
270                      "Only fuse FP ops when the result won't be affected.")));
271   CGBINDOPT(FuseFPOps);
272 
273   static cl::opt<bool> DontPlaceZerosInBSS(
274       "nozero-initialized-in-bss",
275       cl::desc("Don't place zero-initialized symbols into bss section"),
276       cl::init(false));
277   CGBINDOPT(DontPlaceZerosInBSS);
278 
279   static cl::opt<bool> EnableGuaranteedTailCallOpt(
280       "tailcallopt",
281       cl::desc(
282           "Turn fastcc calls into tail calls by (potentially) changing ABI."),
283       cl::init(false));
284   CGBINDOPT(EnableGuaranteedTailCallOpt);
285 
286   static cl::opt<bool> DisableTailCalls(
287       "disable-tail-calls", cl::desc("Never emit tail calls"), cl::init(false));
288   CGBINDOPT(DisableTailCalls);
289 
290   static cl::opt<bool> StackSymbolOrdering(
291       "stack-symbol-ordering", cl::desc("Order local stack symbols."),
292       cl::init(true));
293   CGBINDOPT(StackSymbolOrdering);
294 
295   static cl::opt<unsigned> OverrideStackAlignment(
296       "stack-alignment", cl::desc("Override default stack alignment"),
297       cl::init(0));
298   CGBINDOPT(OverrideStackAlignment);
299 
300   static cl::opt<bool> StackRealign(
301       "stackrealign",
302       cl::desc("Force align the stack to the minimum alignment"),
303       cl::init(false));
304   CGBINDOPT(StackRealign);
305 
306   static cl::opt<std::string> TrapFuncName(
307       "trap-func", cl::Hidden,
308       cl::desc("Emit a call to trap function rather than a trap instruction"),
309       cl::init(""));
310   CGBINDOPT(TrapFuncName);
311 
312   static cl::opt<bool> UseCtors("use-ctors",
313                                 cl::desc("Use .ctors instead of .init_array."),
314                                 cl::init(false));
315   CGBINDOPT(UseCtors);
316 
317   static cl::opt<bool> RelaxELFRelocations(
318       "relax-elf-relocations",
319       cl::desc(
320           "Emit GOTPCRELX/REX_GOTPCRELX instead of GOTPCREL on x86-64 ELF"),
321       cl::init(false));
322   CGBINDOPT(RelaxELFRelocations);
323 
324   static cl::opt<bool> DataSections(
325       "data-sections", cl::desc("Emit data into separate sections"),
326       cl::init(false));
327   CGBINDOPT(DataSections);
328 
329   static cl::opt<bool> FunctionSections(
330       "function-sections", cl::desc("Emit functions into separate sections"),
331       cl::init(false));
332   CGBINDOPT(FunctionSections);
333 
334   static cl::opt<std::string> BBSections(
335       "basicblock-sections",
336       cl::desc("Emit basic blocks into separate sections"),
337       cl::value_desc("all | <function list (file)> | labels | none"),
338       cl::init("none"));
339   CGBINDOPT(BBSections);
340 
341   static cl::opt<unsigned> TLSSize(
342       "tls-size", cl::desc("Bit size of immediate TLS offsets"), cl::init(0));
343   CGBINDOPT(TLSSize);
344 
345   static cl::opt<bool> EmulatedTLS(
346       "emulated-tls", cl::desc("Use emulated TLS model"), cl::init(false));
347   CGBINDOPT(EmulatedTLS);
348 
349   static cl::opt<bool> UniqueSectionNames(
350       "unique-section-names", cl::desc("Give unique names to every section"),
351       cl::init(true));
352   CGBINDOPT(UniqueSectionNames);
353 
354   static cl::opt<bool> UniqueBasicBlockSectionNames(
355       "unique-bb-section-names",
356       cl::desc("Give unique names to every basic block section"),
357       cl::init(false));
358   CGBINDOPT(UniqueBasicBlockSectionNames);
359 
360   static cl::opt<EABI> EABIVersion(
361       "meabi", cl::desc("Set EABI type (default depends on triple):"),
362       cl::init(EABI::Default),
363       cl::values(
364           clEnumValN(EABI::Default, "default", "Triple default EABI version"),
365           clEnumValN(EABI::EABI4, "4", "EABI version 4"),
366           clEnumValN(EABI::EABI5, "5", "EABI version 5"),
367           clEnumValN(EABI::GNU, "gnu", "EABI GNU")));
368   CGBINDOPT(EABIVersion);
369 
370   static cl::opt<DebuggerKind> DebuggerTuningOpt(
371       "debugger-tune", cl::desc("Tune debug info for a particular debugger"),
372       cl::init(DebuggerKind::Default),
373       cl::values(
374           clEnumValN(DebuggerKind::GDB, "gdb", "gdb"),
375           clEnumValN(DebuggerKind::LLDB, "lldb", "lldb"),
376           clEnumValN(DebuggerKind::SCE, "sce", "SCE targets (e.g. PS4)")));
377   CGBINDOPT(DebuggerTuningOpt);
378 
379   static cl::opt<bool> EnableStackSizeSection(
380       "stack-size-section",
381       cl::desc("Emit a section containing stack size metadata"),
382       cl::init(false));
383   CGBINDOPT(EnableStackSizeSection);
384 
385   static cl::opt<bool> EnableAddrsig(
386       "addrsig", cl::desc("Emit an address-significance table"),
387       cl::init(false));
388   CGBINDOPT(EnableAddrsig);
389 
390   static cl::opt<bool> EmitCallSiteInfo(
391       "emit-call-site-info",
392       cl::desc(
393           "Emit call site debug information, if debug information is enabled."),
394       cl::init(false));
395   CGBINDOPT(EmitCallSiteInfo);
396 
397   static cl::opt<bool> EnableDebugEntryValues(
398       "debug-entry-values",
399       cl::desc("Enable debug info for the debug entry values."),
400       cl::init(false));
401   CGBINDOPT(EnableDebugEntryValues);
402 
403   static cl::opt<bool> ForceDwarfFrameSection(
404       "force-dwarf-frame-section",
405       cl::desc("Always emit a debug frame section."), cl::init(false));
406   CGBINDOPT(ForceDwarfFrameSection);
407 
408   static cl::opt<bool> XRayOmitFunctionIndex(
409       "no-xray-index", cl::desc("Don't emit xray_fn_idx section"),
410       cl::init(false));
411   CGBINDOPT(XRayOmitFunctionIndex);
412 
413 #undef CGBINDOPT
414 
415   mc::RegisterMCTargetOptionsFlags();
416 }
417 
418 llvm::BasicBlockSection
419 codegen::getBBSectionsMode(llvm::TargetOptions &Options) {
420   if (getBBSections() == "all")
421     return BasicBlockSection::All;
422   else if (getBBSections() == "labels")
423     return BasicBlockSection::Labels;
424   else if (getBBSections() == "none")
425     return BasicBlockSection::None;
426   else {
427     ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
428         MemoryBuffer::getFile(getBBSections());
429     if (!MBOrErr) {
430       errs() << "Error loading basic block sections function list file: "
431              << MBOrErr.getError().message() << "\n";
432     } else {
433       Options.BBSectionsFuncListBuf = std::move(*MBOrErr);
434     }
435     return BasicBlockSection::List;
436   }
437 }
438 
439 // Common utility function tightly tied to the options listed here. Initializes
440 // a TargetOptions object with CodeGen flags and returns it.
441 TargetOptions codegen::InitTargetOptionsFromCodeGenFlags() {
442   TargetOptions Options;
443   Options.AllowFPOpFusion = getFuseFPOps();
444   Options.UnsafeFPMath = getEnableUnsafeFPMath();
445   Options.NoInfsFPMath = getEnableNoInfsFPMath();
446   Options.NoNaNsFPMath = getEnableNoNaNsFPMath();
447   Options.NoSignedZerosFPMath = getEnableNoSignedZerosFPMath();
448   Options.NoTrappingFPMath = getEnableNoTrappingFPMath();
449 
450   DenormalMode::DenormalModeKind DenormKind = getDenormalFPMath();
451 
452   // FIXME: Should have separate input and output flags
453   Options.setFPDenormalMode(DenormalMode(DenormKind, DenormKind));
454 
455   Options.HonorSignDependentRoundingFPMathOption =
456       getEnableHonorSignDependentRoundingFPMath();
457   if (getFloatABIForCalls() != FloatABI::Default)
458     Options.FloatABIType = getFloatABIForCalls();
459   Options.NoZerosInBSS = getDontPlaceZerosInBSS();
460   Options.GuaranteedTailCallOpt = getEnableGuaranteedTailCallOpt();
461   Options.StackAlignmentOverride = getOverrideStackAlignment();
462   Options.StackSymbolOrdering = getStackSymbolOrdering();
463   Options.UseInitArray = !getUseCtors();
464   Options.RelaxELFRelocations = getRelaxELFRelocations();
465   Options.DataSections = getDataSections();
466   Options.FunctionSections = getFunctionSections();
467   Options.BBSections = getBBSectionsMode(Options);
468   Options.UniqueSectionNames = getUniqueSectionNames();
469   Options.UniqueBasicBlockSectionNames = getUniqueBasicBlockSectionNames();
470   Options.TLSSize = getTLSSize();
471   Options.EmulatedTLS = getEmulatedTLS();
472   Options.ExplicitEmulatedTLS = EmulatedTLSView->getNumOccurrences() > 0;
473   Options.ExceptionModel = getExceptionModel();
474   Options.EmitStackSizeSection = getEnableStackSizeSection();
475   Options.EmitAddrsig = getEnableAddrsig();
476   Options.EmitCallSiteInfo = getEmitCallSiteInfo();
477   Options.EnableDebugEntryValues = getEnableDebugEntryValues();
478   Options.ForceDwarfFrameSection = getForceDwarfFrameSection();
479   Options.XRayOmitFunctionIndex = getXRayOmitFunctionIndex();
480 
481   Options.MCOptions = mc::InitMCTargetOptionsFromFlags();
482 
483   Options.ThreadModel = getThreadModel();
484   Options.EABIVersion = getEABIVersion();
485   Options.DebuggerTuning = getDebuggerTuningOpt();
486 
487   return Options;
488 }
489 
490 std::string codegen::getCPUStr() {
491   // If user asked for the 'native' CPU, autodetect here. If autodection fails,
492   // this will set the CPU to an empty string which tells the target to
493   // pick a basic default.
494   if (getMCPU() == "native")
495     return std::string(sys::getHostCPUName());
496 
497   return getMCPU();
498 }
499 
500 std::string codegen::getFeaturesStr() {
501   SubtargetFeatures Features;
502 
503   // If user asked for the 'native' CPU, we need to autodetect features.
504   // This is necessary for x86 where the CPU might not support all the
505   // features the autodetected CPU name lists in the target. For example,
506   // not all Sandybridge processors support AVX.
507   if (getMCPU() == "native") {
508     StringMap<bool> HostFeatures;
509     if (sys::getHostCPUFeatures(HostFeatures))
510       for (auto &F : HostFeatures)
511         Features.AddFeature(F.first(), F.second);
512   }
513 
514   for (auto const &MAttr : getMAttrs())
515     Features.AddFeature(MAttr);
516 
517   return Features.getString();
518 }
519 
520 std::vector<std::string> codegen::getFeatureList() {
521   SubtargetFeatures Features;
522 
523   // If user asked for the 'native' CPU, we need to autodetect features.
524   // This is necessary for x86 where the CPU might not support all the
525   // features the autodetected CPU name lists in the target. For example,
526   // not all Sandybridge processors support AVX.
527   if (getMCPU() == "native") {
528     StringMap<bool> HostFeatures;
529     if (sys::getHostCPUFeatures(HostFeatures))
530       for (auto &F : HostFeatures)
531         Features.AddFeature(F.first(), F.second);
532   }
533 
534   for (auto const &MAttr : getMAttrs())
535     Features.AddFeature(MAttr);
536 
537   return Features.getFeatures();
538 }
539 
540 void codegen::renderBoolStringAttr(AttrBuilder &B, StringRef Name, bool Val) {
541   B.addAttribute(Name, Val ? "true" : "false");
542 }
543 
544 #define HANDLE_BOOL_ATTR(CL, AttrName)                                         \
545   do {                                                                         \
546     if (CL->getNumOccurrences() > 0 && !F.hasFnAttribute(AttrName))            \
547       renderBoolStringAttr(NewAttrs, AttrName, *CL);                           \
548   } while (0)
549 
550 /// Set function attributes of function \p F based on CPU, Features, and command
551 /// line flags.
552 void codegen::setFunctionAttributes(StringRef CPU, StringRef Features,
553                                     Function &F) {
554   auto &Ctx = F.getContext();
555   AttributeList Attrs = F.getAttributes();
556   AttrBuilder NewAttrs;
557 
558   if (!CPU.empty() && !F.hasFnAttribute("target-cpu"))
559     NewAttrs.addAttribute("target-cpu", CPU);
560   if (!Features.empty()) {
561     // Append the command line features to any that are already on the function.
562     StringRef OldFeatures =
563         F.getFnAttribute("target-features").getValueAsString();
564     if (OldFeatures.empty())
565       NewAttrs.addAttribute("target-features", Features);
566     else {
567       SmallString<256> Appended(OldFeatures);
568       Appended.push_back(',');
569       Appended.append(Features);
570       NewAttrs.addAttribute("target-features", Appended);
571     }
572   }
573   if (FramePointerUsageView->getNumOccurrences() > 0 &&
574       !F.hasFnAttribute("frame-pointer")) {
575     if (getFramePointerUsage() == FramePointer::All)
576       NewAttrs.addAttribute("frame-pointer", "all");
577     else if (getFramePointerUsage() == FramePointer::NonLeaf)
578       NewAttrs.addAttribute("frame-pointer", "non-leaf");
579     else if (getFramePointerUsage() == FramePointer::None)
580       NewAttrs.addAttribute("frame-pointer", "none");
581   }
582   if (DisableTailCallsView->getNumOccurrences() > 0)
583     NewAttrs.addAttribute("disable-tail-calls",
584                           toStringRef(getDisableTailCalls()));
585   if (getStackRealign())
586     NewAttrs.addAttribute("stackrealign");
587 
588   HANDLE_BOOL_ATTR(EnableUnsafeFPMathView, "unsafe-fp-math");
589   HANDLE_BOOL_ATTR(EnableNoInfsFPMathView, "no-infs-fp-math");
590   HANDLE_BOOL_ATTR(EnableNoNaNsFPMathView, "no-nans-fp-math");
591   HANDLE_BOOL_ATTR(EnableNoSignedZerosFPMathView, "no-signed-zeros-fp-math");
592 
593   if (DenormalFPMathView->getNumOccurrences() > 0 &&
594       !F.hasFnAttribute("denormal-fp-math")) {
595     DenormalMode::DenormalModeKind DenormKind = getDenormalFPMath();
596 
597     // FIXME: Command line flag should expose separate input/output modes.
598     NewAttrs.addAttribute("denormal-fp-math",
599                           DenormalMode(DenormKind, DenormKind).str());
600   }
601 
602   if (DenormalFP32MathView->getNumOccurrences() > 0 &&
603       !F.hasFnAttribute("denormal-fp-math-f32")) {
604     // FIXME: Command line flag should expose separate input/output modes.
605     DenormalMode::DenormalModeKind DenormKind = getDenormalFP32Math();
606 
607     NewAttrs.addAttribute(
608       "denormal-fp-math-f32",
609       DenormalMode(DenormKind, DenormKind).str());
610   }
611 
612   if (TrapFuncNameView->getNumOccurrences() > 0)
613     for (auto &B : F)
614       for (auto &I : B)
615         if (auto *Call = dyn_cast<CallInst>(&I))
616           if (const auto *F = Call->getCalledFunction())
617             if (F->getIntrinsicID() == Intrinsic::debugtrap ||
618                 F->getIntrinsicID() == Intrinsic::trap)
619               Call->addAttribute(
620                   AttributeList::FunctionIndex,
621                   Attribute::get(Ctx, "trap-func-name", getTrapFuncName()));
622 
623   // Let NewAttrs override Attrs.
624   F.setAttributes(
625       Attrs.addAttributes(Ctx, AttributeList::FunctionIndex, NewAttrs));
626 }
627 
628 /// Set function attributes of functions in Module M based on CPU,
629 /// Features, and command line flags.
630 void codegen::setFunctionAttributes(StringRef CPU, StringRef Features,
631                                     Module &M) {
632   for (Function &F : M)
633     setFunctionAttributes(CPU, Features, F);
634 }
635