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1//===-- CommandFlags.h - 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/ADT/StringExtras.h"
16#include "llvm/IR/Instructions.h"
17#include "llvm/IR/Intrinsics.h"
18#include "llvm/IR/Module.h"
19#include "llvm/MC/MCTargetOptionsCommandFlags.inc"
20#include "llvm/MC/SubtargetFeature.h"
21#include "llvm/Support/CodeGen.h"
22#include "llvm/Support/CommandLine.h"
23#include "llvm/Support/Host.h"
24#include "llvm/Target/TargetMachine.h"
25#include "llvm/Target/TargetOptions.h"
26#include <string>
27using namespace llvm;
28
29static cl::opt<std::string>
30    MArch("march",
31          cl::desc("Architecture to generate code for (see --version)"));
32
33static cl::opt<std::string>
34    MCPU("mcpu",
35         cl::desc("Target a specific cpu type (-mcpu=help for details)"),
36         cl::value_desc("cpu-name"), cl::init(""));
37
38static cl::list<std::string>
39    MAttrs("mattr", cl::CommaSeparated,
40           cl::desc("Target specific attributes (-mattr=help for details)"),
41           cl::value_desc("a1,+a2,-a3,..."));
42
43static cl::opt<Reloc::Model> RelocModel(
44    "relocation-model", cl::desc("Choose relocation model"),
45    cl::values(
46        clEnumValN(Reloc::Static, "static", "Non-relocatable code"),
47        clEnumValN(Reloc::PIC_, "pic",
48                   "Fully relocatable, position independent code"),
49        clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
50                   "Relocatable external references, non-relocatable code"),
51        clEnumValN(Reloc::ROPI, "ropi",
52                   "Code and read-only data relocatable, accessed PC-relative"),
53        clEnumValN(
54            Reloc::RWPI, "rwpi",
55            "Read-write data relocatable, accessed relative to static base"),
56        clEnumValN(Reloc::ROPI_RWPI, "ropi-rwpi",
57                   "Combination of ropi and rwpi")));
58
59LLVM_ATTRIBUTE_UNUSED static Optional<Reloc::Model> getRelocModel() {
60  if (RelocModel.getNumOccurrences()) {
61    Reloc::Model R = RelocModel;
62    return R;
63  }
64  return None;
65}
66
67static cl::opt<ThreadModel::Model> TMModel(
68    "thread-model", cl::desc("Choose threading model"),
69    cl::init(ThreadModel::POSIX),
70    cl::values(clEnumValN(ThreadModel::POSIX, "posix", "POSIX thread model"),
71               clEnumValN(ThreadModel::Single, "single",
72                          "Single thread model")));
73
74static cl::opt<llvm::CodeModel::Model> CMModel(
75    "code-model", cl::desc("Choose code model"),
76    cl::values(clEnumValN(CodeModel::Tiny, "tiny", "Tiny code model"),
77               clEnumValN(CodeModel::Small, "small", "Small code model"),
78               clEnumValN(CodeModel::Kernel, "kernel", "Kernel code model"),
79               clEnumValN(CodeModel::Medium, "medium", "Medium code model"),
80               clEnumValN(CodeModel::Large, "large", "Large code model")));
81
82LLVM_ATTRIBUTE_UNUSED static Optional<CodeModel::Model> getCodeModel() {
83  if (CMModel.getNumOccurrences()) {
84    CodeModel::Model M = CMModel;
85    return M;
86  }
87  return None;
88}
89
90static cl::opt<llvm::ExceptionHandling> ExceptionModel(
91    "exception-model", cl::desc("exception model"),
92    cl::init(ExceptionHandling::None),
93    cl::values(
94        clEnumValN(ExceptionHandling::None, "default",
95                   "default exception handling model"),
96        clEnumValN(ExceptionHandling::DwarfCFI, "dwarf",
97                   "DWARF-like CFI based exception handling"),
98        clEnumValN(ExceptionHandling::SjLj, "sjlj", "SjLj exception handling"),
99        clEnumValN(ExceptionHandling::ARM, "arm", "ARM EHABI exceptions"),
100        clEnumValN(ExceptionHandling::WinEH, "wineh",
101                   "Windows exception model"),
102        clEnumValN(ExceptionHandling::Wasm, "wasm",
103                   "WebAssembly exception handling")));
104
105static cl::opt<CodeGenFileType> FileType(
106    "filetype", cl::init(CGFT_AssemblyFile),
107    cl::desc(
108        "Choose a file type (not all types are supported by all targets):"),
109    cl::values(clEnumValN(CGFT_AssemblyFile, "asm",
110                          "Emit an assembly ('.s') file"),
111               clEnumValN(CGFT_ObjectFile, "obj",
112                          "Emit a native object ('.o') file"),
113               clEnumValN(CGFT_Null, "null",
114                          "Emit nothing, for performance testing")));
115
116static cl::opt<llvm::FramePointer::FP> FramePointerUsage(
117    "frame-pointer", cl::desc("Specify frame pointer elimination optimization"),
118    cl::init(llvm::FramePointer::None),
119    cl::values(
120        clEnumValN(llvm::FramePointer::All, "all",
121                   "Disable frame pointer elimination"),
122        clEnumValN(llvm::FramePointer::NonLeaf, "non-leaf",
123                   "Disable frame pointer elimination for non-leaf frame"),
124        clEnumValN(llvm::FramePointer::None, "none",
125                   "Enable frame pointer elimination")));
126
127static cl::opt<bool> EnableUnsafeFPMath(
128    "enable-unsafe-fp-math",
129    cl::desc("Enable optimizations that may decrease FP precision"),
130    cl::init(false));
131
132static cl::opt<bool> EnableNoInfsFPMath(
133    "enable-no-infs-fp-math",
134    cl::desc("Enable FP math optimizations that assume no +-Infs"),
135    cl::init(false));
136
137static cl::opt<bool> EnableNoNaNsFPMath(
138    "enable-no-nans-fp-math",
139    cl::desc("Enable FP math optimizations that assume no NaNs"),
140    cl::init(false));
141
142static cl::opt<bool> EnableNoSignedZerosFPMath(
143    "enable-no-signed-zeros-fp-math",
144    cl::desc("Enable FP math optimizations that assume "
145             "the sign of 0 is insignificant"),
146    cl::init(false));
147
148static cl::opt<bool>
149    EnableNoTrappingFPMath("enable-no-trapping-fp-math",
150                           cl::desc("Enable setting the FP exceptions build "
151                                    "attribute not to use exceptions"),
152                           cl::init(false));
153
154static cl::opt<llvm::FPDenormal::DenormalMode> DenormalFPMath(
155    "denormal-fp-math",
156    cl::desc("Select which denormal numbers the code is permitted to require"),
157    cl::init(FPDenormal::IEEE),
158    cl::values(clEnumValN(FPDenormal::IEEE, "ieee",
159                          "IEEE 754 denormal numbers"),
160               clEnumValN(FPDenormal::PreserveSign, "preserve-sign",
161                          "the sign of a  flushed-to-zero number is preserved "
162                          "in the sign of 0"),
163               clEnumValN(FPDenormal::PositiveZero, "positive-zero",
164                          "denormals are flushed to positive zero")));
165
166static cl::opt<bool> EnableHonorSignDependentRoundingFPMath(
167    "enable-sign-dependent-rounding-fp-math", cl::Hidden,
168    cl::desc("Force codegen to assume rounding mode can change dynamically"),
169    cl::init(false));
170
171static cl::opt<llvm::FloatABI::ABIType> FloatABIForCalls(
172    "float-abi", cl::desc("Choose float ABI type"), cl::init(FloatABI::Default),
173    cl::values(clEnumValN(FloatABI::Default, "default",
174                          "Target default float ABI type"),
175               clEnumValN(FloatABI::Soft, "soft",
176                          "Soft float ABI (implied by -soft-float)"),
177               clEnumValN(FloatABI::Hard, "hard",
178                          "Hard float ABI (uses FP registers)")));
179
180static cl::opt<llvm::FPOpFusion::FPOpFusionMode> FuseFPOps(
181    "fp-contract", cl::desc("Enable aggressive formation of fused FP ops"),
182    cl::init(FPOpFusion::Standard),
183    cl::values(
184        clEnumValN(FPOpFusion::Fast, "fast", "Fuse FP ops whenever profitable"),
185        clEnumValN(FPOpFusion::Standard, "on", "Only fuse 'blessed' FP ops."),
186        clEnumValN(FPOpFusion::Strict, "off",
187                   "Only fuse FP ops when the result won't be affected.")));
188
189static cl::opt<bool> DontPlaceZerosInBSS(
190    "nozero-initialized-in-bss",
191    cl::desc("Don't place zero-initialized symbols into bss section"),
192    cl::init(false));
193
194static cl::opt<bool> EnableGuaranteedTailCallOpt(
195    "tailcallopt",
196    cl::desc(
197        "Turn fastcc calls into tail calls by (potentially) changing ABI."),
198    cl::init(false));
199
200static cl::opt<bool> DisableTailCalls("disable-tail-calls",
201                                      cl::desc("Never emit tail calls"),
202                                      cl::init(false));
203
204static cl::opt<bool> StackSymbolOrdering("stack-symbol-ordering",
205                                         cl::desc("Order local stack symbols."),
206                                         cl::init(true));
207
208static cl::opt<unsigned>
209    OverrideStackAlignment("stack-alignment",
210                           cl::desc("Override default stack alignment"),
211                           cl::init(0));
212
213static cl::opt<bool>
214    StackRealign("stackrealign",
215                 cl::desc("Force align the stack to the minimum alignment"),
216                 cl::init(false));
217
218static cl::opt<std::string> TrapFuncName(
219    "trap-func", cl::Hidden,
220    cl::desc("Emit a call to trap function rather than a trap instruction"),
221    cl::init(""));
222
223static cl::opt<bool> UseCtors("use-ctors",
224                              cl::desc("Use .ctors instead of .init_array."),
225                              cl::init(false));
226
227static cl::opt<bool> RelaxELFRelocations(
228    "relax-elf-relocations",
229    cl::desc("Emit GOTPCRELX/REX_GOTPCRELX instead of GOTPCREL on x86-64 ELF"),
230    cl::init(false));
231
232static cl::opt<bool> DataSections("data-sections",
233                                  cl::desc("Emit data into separate sections"),
234                                  cl::init(false));
235
236static cl::opt<bool>
237    FunctionSections("function-sections",
238                     cl::desc("Emit functions into separate sections"),
239                     cl::init(false));
240
241static cl::opt<unsigned> TLSSize("tls-size",
242                                 cl::desc("Bit size of immediate TLS offsets"),
243                                 cl::init(0));
244
245static cl::opt<bool> EmulatedTLS("emulated-tls",
246                                 cl::desc("Use emulated TLS model"),
247                                 cl::init(false));
248
249static cl::opt<bool>
250    UniqueSectionNames("unique-section-names",
251                       cl::desc("Give unique names to every section"),
252                       cl::init(true));
253
254static cl::opt<llvm::EABI>
255    EABIVersion("meabi", cl::desc("Set EABI type (default depends on triple):"),
256                cl::init(EABI::Default),
257                cl::values(clEnumValN(EABI::Default, "default",
258                                      "Triple default EABI version"),
259                           clEnumValN(EABI::EABI4, "4", "EABI version 4"),
260                           clEnumValN(EABI::EABI5, "5", "EABI version 5"),
261                           clEnumValN(EABI::GNU, "gnu", "EABI GNU")));
262
263static cl::opt<DebuggerKind> DebuggerTuningOpt(
264    "debugger-tune", cl::desc("Tune debug info for a particular debugger"),
265    cl::init(DebuggerKind::Default),
266    cl::values(clEnumValN(DebuggerKind::GDB, "gdb", "gdb"),
267               clEnumValN(DebuggerKind::LLDB, "lldb", "lldb"),
268               clEnumValN(DebuggerKind::SCE, "sce", "SCE targets (e.g. PS4)")));
269
270static cl::opt<bool> EnableStackSizeSection(
271    "stack-size-section",
272    cl::desc("Emit a section containing stack size metadata"), cl::init(false));
273
274static cl::opt<bool>
275    EnableAddrsig("addrsig", cl::desc("Emit an address-significance table"),
276                  cl::init(false));
277
278static cl::opt<bool>
279    EnableDebugEntryValues("debug-entry-values",
280                           cl::desc("Emit debug info about parameter's entry values"),
281                           cl::init(false));
282
283static cl::opt<bool>
284    ForceDwarfFrameSection("force-dwarf-frame-section",
285                           cl::desc("Always emit a debug frame section."),
286                           cl::init(false));
287
288// Common utility function tightly tied to the options listed here. Initializes
289// a TargetOptions object with CodeGen flags and returns it.
290static TargetOptions InitTargetOptionsFromCodeGenFlags() {
291  TargetOptions Options;
292  Options.AllowFPOpFusion = FuseFPOps;
293  Options.UnsafeFPMath = EnableUnsafeFPMath;
294  Options.NoInfsFPMath = EnableNoInfsFPMath;
295  Options.NoNaNsFPMath = EnableNoNaNsFPMath;
296  Options.NoSignedZerosFPMath = EnableNoSignedZerosFPMath;
297  Options.NoTrappingFPMath = EnableNoTrappingFPMath;
298  Options.FPDenormalMode = DenormalFPMath;
299  Options.HonorSignDependentRoundingFPMathOption =
300      EnableHonorSignDependentRoundingFPMath;
301  if (FloatABIForCalls != FloatABI::Default)
302    Options.FloatABIType = FloatABIForCalls;
303  Options.NoZerosInBSS = DontPlaceZerosInBSS;
304  Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
305  Options.StackAlignmentOverride = OverrideStackAlignment;
306  Options.StackSymbolOrdering = StackSymbolOrdering;
307  Options.UseInitArray = !UseCtors;
308  Options.RelaxELFRelocations = RelaxELFRelocations;
309  Options.DataSections = DataSections;
310  Options.FunctionSections = FunctionSections;
311  Options.UniqueSectionNames = UniqueSectionNames;
312  Options.TLSSize = TLSSize;
313  Options.EmulatedTLS = EmulatedTLS;
314  Options.ExplicitEmulatedTLS = EmulatedTLS.getNumOccurrences() > 0;
315  Options.ExceptionModel = ExceptionModel;
316  Options.EmitStackSizeSection = EnableStackSizeSection;
317  Options.EmitAddrsig = EnableAddrsig;
318  Options.EnableDebugEntryValues = EnableDebugEntryValues;
319  Options.ForceDwarfFrameSection = ForceDwarfFrameSection;
320
321  Options.MCOptions = InitMCTargetOptionsFromFlags();
322
323  Options.ThreadModel = TMModel;
324  Options.EABIVersion = EABIVersion;
325  Options.DebuggerTuning = DebuggerTuningOpt;
326
327  return Options;
328}
329
330LLVM_ATTRIBUTE_UNUSED static std::string getCPUStr() {
331  // If user asked for the 'native' CPU, autodetect here. If autodection fails,
332  // this will set the CPU to an empty string which tells the target to
333  // pick a basic default.
334  if (MCPU == "native")
335    return sys::getHostCPUName();
336
337  return MCPU;
338}
339
340LLVM_ATTRIBUTE_UNUSED static std::string getFeaturesStr() {
341  SubtargetFeatures Features;
342
343  // If user asked for the 'native' CPU, we need to autodetect features.
344  // This is necessary for x86 where the CPU might not support all the
345  // features the autodetected CPU name lists in the target. For example,
346  // not all Sandybridge processors support AVX.
347  if (MCPU == "native") {
348    StringMap<bool> HostFeatures;
349    if (sys::getHostCPUFeatures(HostFeatures))
350      for (auto &F : HostFeatures)
351        Features.AddFeature(F.first(), F.second);
352  }
353
354  for (unsigned i = 0; i != MAttrs.size(); ++i)
355    Features.AddFeature(MAttrs[i]);
356
357  return Features.getString();
358}
359
360LLVM_ATTRIBUTE_UNUSED static std::vector<std::string> getFeatureList() {
361  SubtargetFeatures Features;
362
363  // If user asked for the 'native' CPU, we need to autodetect features.
364  // This is necessary for x86 where the CPU might not support all the
365  // features the autodetected CPU name lists in the target. For example,
366  // not all Sandybridge processors support AVX.
367  if (MCPU == "native") {
368    StringMap<bool> HostFeatures;
369    if (sys::getHostCPUFeatures(HostFeatures))
370      for (auto &F : HostFeatures)
371        Features.AddFeature(F.first(), F.second);
372  }
373
374  for (unsigned i = 0; i != MAttrs.size(); ++i)
375    Features.AddFeature(MAttrs[i]);
376
377  return Features.getFeatures();
378}
379
380/// Set function attributes of function \p F based on CPU, Features, and command
381/// line flags.
382LLVM_ATTRIBUTE_UNUSED static void
383setFunctionAttributes(StringRef CPU, StringRef Features, Function &F) {
384  auto &Ctx = F.getContext();
385  AttributeList Attrs = F.getAttributes();
386  AttrBuilder NewAttrs;
387
388  if (!CPU.empty() && !F.hasFnAttribute("target-cpu"))
389    NewAttrs.addAttribute("target-cpu", CPU);
390  if (!Features.empty())
391    NewAttrs.addAttribute("target-features", Features);
392  if (FramePointerUsage.getNumOccurrences() > 0) {
393    if (FramePointerUsage == llvm::FramePointer::All)
394      NewAttrs.addAttribute("frame-pointer", "all");
395    else if (FramePointerUsage == llvm::FramePointer::NonLeaf)
396      NewAttrs.addAttribute("frame-pointer", "non-leaf");
397    else if (FramePointerUsage == llvm::FramePointer::None)
398      NewAttrs.addAttribute("frame-pointer", "none");
399  }
400  if (DisableTailCalls.getNumOccurrences() > 0)
401    NewAttrs.addAttribute("disable-tail-calls",
402                          toStringRef(DisableTailCalls));
403  if (StackRealign)
404    NewAttrs.addAttribute("stackrealign");
405
406  if (TrapFuncName.getNumOccurrences() > 0)
407    for (auto &B : F)
408      for (auto &I : B)
409        if (auto *Call = dyn_cast<CallInst>(&I))
410          if (const auto *F = Call->getCalledFunction())
411            if (F->getIntrinsicID() == Intrinsic::debugtrap ||
412                F->getIntrinsicID() == Intrinsic::trap)
413              Call->addAttribute(
414                llvm::AttributeList::FunctionIndex,
415                Attribute::get(Ctx, "trap-func-name", TrapFuncName));
416
417  // Let NewAttrs override Attrs.
418  F.setAttributes(
419    Attrs.addAttributes(Ctx, AttributeList::FunctionIndex, NewAttrs));
420}
421
422/// Set function attributes of functions in Module M based on CPU,
423/// Features, and command line flags.
424LLVM_ATTRIBUTE_UNUSED static void
425setFunctionAttributes(StringRef CPU, StringRef Features, Module &M) {
426  for (Function &F : M)
427    setFunctionAttributes(CPU, Features, F);
428}
429