1 //===--- AMDGPU.cpp - AMDGPU ToolChain Implementations ----------*- 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 #include "AMDGPU.h"
10 #include "CommonArgs.h"
11 #include "InputInfo.h"
12 #include "clang/Driver/Compilation.h"
13 #include "clang/Driver/DriverDiagnostic.h"
14 #include "llvm/Option/ArgList.h"
15 #include "llvm/Support/Path.h"
16 #include "llvm/Support/VirtualFileSystem.h"
17 
18 using namespace clang::driver;
19 using namespace clang::driver::tools;
20 using namespace clang::driver::toolchains;
21 using namespace clang;
22 using namespace llvm::opt;
23 
24 void RocmInstallationDetector::scanLibDevicePath() {
25   assert(!LibDevicePath.empty());
26 
27   const StringRef Suffix(".bc");
28 
29   std::error_code EC;
30   for (llvm::sys::fs::directory_iterator LI(LibDevicePath, EC), LE;
31        !EC && LI != LE; LI = LI.increment(EC)) {
32     StringRef FilePath = LI->path();
33     StringRef FileName = llvm::sys::path::filename(FilePath);
34     if (!FileName.endswith(Suffix))
35       continue;
36 
37     StringRef BaseName = FileName.drop_back(Suffix.size());
38 
39     if (BaseName == "ocml") {
40       OCML = FilePath;
41     } else if (BaseName == "ockl") {
42       OCKL = FilePath;
43     } else if (BaseName == "opencl") {
44       OpenCL = FilePath;
45     } else if (BaseName == "hip") {
46       HIP = FilePath;
47     } else if (BaseName == "oclc_finite_only_off") {
48       FiniteOnly.Off = FilePath;
49     } else if (BaseName == "oclc_finite_only_on") {
50       FiniteOnly.On = FilePath;
51     } else if (BaseName == "oclc_daz_opt_on") {
52       DenormalsAreZero.On = FilePath;
53     } else if (BaseName == "oclc_daz_opt_off") {
54       DenormalsAreZero.Off = FilePath;
55     } else if (BaseName == "oclc_correctly_rounded_sqrt_on") {
56       CorrectlyRoundedSqrt.On = FilePath;
57     } else if (BaseName == "oclc_correctly_rounded_sqrt_off") {
58       CorrectlyRoundedSqrt.Off = FilePath;
59     } else if (BaseName == "oclc_unsafe_math_on") {
60       UnsafeMath.On = FilePath;
61     } else if (BaseName == "oclc_unsafe_math_off") {
62       UnsafeMath.Off = FilePath;
63     } else if (BaseName == "oclc_wavefrontsize64_on") {
64       WavefrontSize64.On = FilePath;
65     } else if (BaseName == "oclc_wavefrontsize64_off") {
66       WavefrontSize64.Off = FilePath;
67     } else {
68       // Process all bitcode filenames that look like
69       // ocl_isa_version_XXX.amdgcn.bc
70       const StringRef DeviceLibPrefix = "oclc_isa_version_";
71       if (!BaseName.startswith(DeviceLibPrefix))
72         continue;
73 
74       StringRef IsaVersionNumber =
75         BaseName.drop_front(DeviceLibPrefix.size());
76 
77       llvm::Twine GfxName = Twine("gfx") + IsaVersionNumber;
78       SmallString<8> Tmp;
79       LibDeviceMap.insert(
80         std::make_pair(GfxName.toStringRef(Tmp), FilePath.str()));
81     }
82   }
83 }
84 
85 RocmInstallationDetector::RocmInstallationDetector(
86     const Driver &D, const llvm::Triple &HostTriple,
87     const llvm::opt::ArgList &Args)
88     : D(D) {
89   struct Candidate {
90     std::string Path;
91     bool StrictChecking;
92 
93     Candidate(std::string Path, bool StrictChecking = false)
94         : Path(Path), StrictChecking(StrictChecking) {}
95   };
96 
97   SmallVector<Candidate, 4> Candidates;
98 
99   if (Args.hasArg(clang::driver::options::OPT_rocm_path_EQ)) {
100     Candidates.emplace_back(
101         Args.getLastArgValue(clang::driver::options::OPT_rocm_path_EQ).str());
102   } else {
103     // Try to find relative to the compiler binary.
104     const char *InstallDir = D.getInstalledDir();
105 
106     // Check both a normal Unix prefix position of the clang binary, as well as
107     // the Windows-esque layout the ROCm packages use with the host architecture
108     // subdirectory of bin.
109 
110     StringRef ParentDir = llvm::sys::path::parent_path(InstallDir);
111     if (ParentDir == HostTriple.getArchName())
112       ParentDir = llvm::sys::path::parent_path(ParentDir);
113 
114     if (ParentDir == "bin") {
115       Candidates.emplace_back(llvm::sys::path::parent_path(ParentDir).str(),
116                               /*StrictChecking=*/true);
117     }
118 
119     Candidates.emplace_back(D.SysRoot + "/opt/rocm");
120   }
121 
122   bool NoBuiltinLibs = Args.hasArg(options::OPT_nogpulib);
123 
124   assert(LibDevicePath.empty());
125 
126   if (Args.hasArg(clang::driver::options::OPT_hip_device_lib_path_EQ)) {
127     LibDevicePath
128       = Args.getLastArgValue(clang::driver::options::OPT_hip_device_lib_path_EQ);
129   } else if (const char *LibPathEnv = ::getenv("HIP_DEVICE_LIB_PATH")) {
130     LibDevicePath = LibPathEnv;
131   }
132 
133   if (!LibDevicePath.empty()) {
134     // Maintain compatability with HIP flag/envvar pointing directly at the
135     // bitcode library directory. This points directly at the library path instead
136     // of the rocm root installation.
137     if (!D.getVFS().exists(LibDevicePath))
138       return;
139 
140     scanLibDevicePath();
141     IsValid = allGenericLibsValid() && !LibDeviceMap.empty();
142     return;
143   }
144 
145   for (const auto &Candidate : Candidates) {
146     InstallPath = Candidate.Path;
147     if (InstallPath.empty() || !D.getVFS().exists(InstallPath))
148       continue;
149 
150     // The install path situation in old versions of ROCm is a real mess, and
151     // use a different install layout. Multiple copies of the device libraries
152     // exist for each frontend project, and differ depending on which build
153     // system produced the packages. Standalone OpenCL builds also have a
154     // different directory structure from the ROCm OpenCL package.
155     //
156     // The desired structure is (${ROCM_ROOT} or
157     // ${OPENCL_ROOT})/amdgcn/bitcode/*, so try to detect this layout.
158 
159     // BinPath = InstallPath + "/bin";
160     llvm::sys::path::append(IncludePath, InstallPath, "include");
161     llvm::sys::path::append(LibDevicePath, InstallPath, "amdgcn", "bitcode");
162 
163     auto &FS = D.getVFS();
164 
165     // We don't need the include path for OpenCL, since clang already ships with
166     // the default header.
167 
168     bool CheckLibDevice = (!NoBuiltinLibs || Candidate.StrictChecking);
169     if (CheckLibDevice && !FS.exists(LibDevicePath))
170       continue;
171 
172     scanLibDevicePath();
173 
174     if (!NoBuiltinLibs) {
175       // Check that the required non-target libraries are all available.
176       if (!allGenericLibsValid())
177         continue;
178 
179       // Check that we have found at least one libdevice that we can link in if
180       // -nobuiltinlib hasn't been specified.
181       if (LibDeviceMap.empty())
182         continue;
183     }
184 
185     IsValid = true;
186     break;
187   }
188 }
189 
190 void RocmInstallationDetector::print(raw_ostream &OS) const {
191   if (isValid())
192     OS << "Found ROCm installation: " << InstallPath << '\n';
193 }
194 
195 void amdgpu::Linker::ConstructJob(Compilation &C, const JobAction &JA,
196                                   const InputInfo &Output,
197                                   const InputInfoList &Inputs,
198                                   const ArgList &Args,
199                                   const char *LinkingOutput) const {
200 
201   std::string Linker = getToolChain().GetProgramPath(getShortName());
202   ArgStringList CmdArgs;
203   AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
204   CmdArgs.push_back("-shared");
205   CmdArgs.push_back("-o");
206   CmdArgs.push_back(Output.getFilename());
207   C.addCommand(std::make_unique<Command>(JA, *this, Args.MakeArgString(Linker),
208                                           CmdArgs, Inputs));
209 }
210 
211 void amdgpu::getAMDGPUTargetFeatures(const Driver &D,
212                                      const llvm::opt::ArgList &Args,
213                                      std::vector<StringRef> &Features) {
214   if (const Arg *dAbi = Args.getLastArg(options::OPT_mamdgpu_debugger_abi))
215     D.Diag(diag::err_drv_clang_unsupported) << dAbi->getAsString(Args);
216 
217   if (Args.getLastArg(options::OPT_mwavefrontsize64)) {
218     Features.push_back("-wavefrontsize16");
219     Features.push_back("-wavefrontsize32");
220     Features.push_back("+wavefrontsize64");
221   }
222   if (Args.getLastArg(options::OPT_mno_wavefrontsize64)) {
223     Features.push_back("-wavefrontsize16");
224     Features.push_back("+wavefrontsize32");
225     Features.push_back("-wavefrontsize64");
226   }
227 
228   handleTargetFeaturesGroup(
229     Args, Features, options::OPT_m_amdgpu_Features_Group);
230 }
231 
232 /// AMDGPU Toolchain
233 AMDGPUToolChain::AMDGPUToolChain(const Driver &D, const llvm::Triple &Triple,
234                                  const ArgList &Args)
235     : Generic_ELF(D, Triple, Args),
236       OptionsDefault({{options::OPT_O, "3"},
237                       {options::OPT_cl_std_EQ, "CL1.2"}}) {}
238 
239 Tool *AMDGPUToolChain::buildLinker() const {
240   return new tools::amdgpu::Linker(*this);
241 }
242 
243 DerivedArgList *
244 AMDGPUToolChain::TranslateArgs(const DerivedArgList &Args, StringRef BoundArch,
245                                Action::OffloadKind DeviceOffloadKind) const {
246 
247   DerivedArgList *DAL =
248       Generic_ELF::TranslateArgs(Args, BoundArch, DeviceOffloadKind);
249 
250   // Do nothing if not OpenCL (-x cl)
251   if (!Args.getLastArgValue(options::OPT_x).equals("cl"))
252     return DAL;
253 
254   if (!DAL)
255     DAL = new DerivedArgList(Args.getBaseArgs());
256   for (auto *A : Args)
257     DAL->append(A);
258 
259   const OptTable &Opts = getDriver().getOpts();
260 
261   // Phase 1 (.cl -> .bc)
262   if (Args.hasArg(options::OPT_c) && Args.hasArg(options::OPT_emit_llvm)) {
263     DAL->AddFlagArg(nullptr, Opts.getOption(getTriple().isArch64Bit()
264                                                 ? options::OPT_m64
265                                                 : options::OPT_m32));
266 
267     // Have to check OPT_O4, OPT_O0 & OPT_Ofast separately
268     // as they defined that way in Options.td
269     if (!Args.hasArg(options::OPT_O, options::OPT_O0, options::OPT_O4,
270                      options::OPT_Ofast))
271       DAL->AddJoinedArg(nullptr, Opts.getOption(options::OPT_O),
272                         getOptionDefault(options::OPT_O));
273   }
274 
275   return DAL;
276 }
277 
278 bool AMDGPUToolChain::getDefaultDenormsAreZeroForTarget(
279     llvm::AMDGPU::GPUKind Kind) {
280 
281   // Assume nothing without a specific target.
282   if (Kind == llvm::AMDGPU::GK_NONE)
283     return false;
284 
285   const unsigned ArchAttr = llvm::AMDGPU::getArchAttrAMDGCN(Kind);
286 
287   // Default to enabling f32 denormals by default on subtargets where fma is
288   // fast with denormals
289   const bool BothDenormAndFMAFast =
290       (ArchAttr & llvm::AMDGPU::FEATURE_FAST_FMA_F32) &&
291       (ArchAttr & llvm::AMDGPU::FEATURE_FAST_DENORMAL_F32);
292   return !BothDenormAndFMAFast;
293 }
294 
295 llvm::DenormalMode AMDGPUToolChain::getDefaultDenormalModeForType(
296     const llvm::opt::ArgList &DriverArgs, const JobAction &JA,
297     const llvm::fltSemantics *FPType) const {
298   // Denormals should always be enabled for f16 and f64.
299   if (!FPType || FPType != &llvm::APFloat::IEEEsingle())
300     return llvm::DenormalMode::getIEEE();
301 
302   if (JA.getOffloadingDeviceKind() == Action::OFK_HIP ||
303       JA.getOffloadingDeviceKind() == Action::OFK_Cuda) {
304     auto Kind = llvm::AMDGPU::parseArchAMDGCN(JA.getOffloadingArch());
305     if (FPType && FPType == &llvm::APFloat::IEEEsingle() &&
306         DriverArgs.hasFlag(options::OPT_fcuda_flush_denormals_to_zero,
307                            options::OPT_fno_cuda_flush_denormals_to_zero,
308                            getDefaultDenormsAreZeroForTarget(Kind)))
309       return llvm::DenormalMode::getPreserveSign();
310 
311     return llvm::DenormalMode::getIEEE();
312   }
313 
314   const StringRef GpuArch = DriverArgs.getLastArgValue(options::OPT_mcpu_EQ);
315   auto Kind = llvm::AMDGPU::parseArchAMDGCN(GpuArch);
316 
317   // TODO: There are way too many flags that change this. Do we need to check
318   // them all?
319   bool DAZ = DriverArgs.hasArg(options::OPT_cl_denorms_are_zero) ||
320              getDefaultDenormsAreZeroForTarget(Kind);
321 
322   // Outputs are flushed to zero (FTZ), preserving sign. Denormal inputs are
323   // also implicit treated as zero (DAZ).
324   return DAZ ? llvm::DenormalMode::getPreserveSign() :
325                llvm::DenormalMode::getIEEE();
326 }
327 
328 bool AMDGPUToolChain::isWave64(const llvm::opt::ArgList &DriverArgs,
329                                llvm::AMDGPU::GPUKind Kind) {
330   const unsigned ArchAttr = llvm::AMDGPU::getArchAttrAMDGCN(Kind);
331   static bool HasWave32 = (ArchAttr & llvm::AMDGPU::FEATURE_WAVE32);
332 
333   return !HasWave32 || DriverArgs.hasFlag(
334     options::OPT_mwavefrontsize64, options::OPT_mno_wavefrontsize64, false);
335 }
336 
337 
338 /// ROCM Toolchain
339 ROCMToolChain::ROCMToolChain(const Driver &D, const llvm::Triple &Triple,
340                              const ArgList &Args)
341   : AMDGPUToolChain(D, Triple, Args),
342     RocmInstallation(D, Triple, Args) { }
343 
344 void AMDGPUToolChain::addClangTargetOptions(
345     const llvm::opt::ArgList &DriverArgs,
346     llvm::opt::ArgStringList &CC1Args,
347     Action::OffloadKind DeviceOffloadingKind) const {
348   // Default to "hidden" visibility, as object level linking will not be
349   // supported for the foreseeable future.
350   if (!DriverArgs.hasArg(options::OPT_fvisibility_EQ,
351                          options::OPT_fvisibility_ms_compat)) {
352     CC1Args.push_back("-fvisibility");
353     CC1Args.push_back("hidden");
354     CC1Args.push_back("-fapply-global-visibility-to-externs");
355   }
356 }
357 
358 void ROCMToolChain::addClangTargetOptions(
359     const llvm::opt::ArgList &DriverArgs, llvm::opt::ArgStringList &CC1Args,
360     Action::OffloadKind DeviceOffloadingKind) const {
361   AMDGPUToolChain::addClangTargetOptions(DriverArgs, CC1Args,
362                                          DeviceOffloadingKind);
363 
364   if (DriverArgs.hasArg(options::OPT_nogpulib))
365     return;
366 
367   if (!RocmInstallation.isValid()) {
368     getDriver().Diag(diag::err_drv_no_rocm_installation);
369     return;
370   }
371 
372   // Get the device name and canonicalize it
373   const StringRef GpuArch = DriverArgs.getLastArgValue(options::OPT_mcpu_EQ);
374   auto Kind = llvm::AMDGPU::parseArchAMDGCN(GpuArch);
375   const StringRef CanonArch = llvm::AMDGPU::getArchNameAMDGCN(Kind);
376   std::string LibDeviceFile = RocmInstallation.getLibDeviceFile(CanonArch);
377   if (LibDeviceFile.empty()) {
378     getDriver().Diag(diag::err_drv_no_rocm_device_lib) << GpuArch;
379     return;
380   }
381 
382   bool Wave64 = isWave64(DriverArgs, Kind);
383 
384   // TODO: There are way too many flags that change this. Do we need to check
385   // them all?
386   bool DAZ = DriverArgs.hasArg(options::OPT_cl_denorms_are_zero) ||
387              getDefaultDenormsAreZeroForTarget(Kind);
388   bool FiniteOnly = DriverArgs.hasArg(options::OPT_cl_finite_math_only);
389 
390   bool UnsafeMathOpt =
391       DriverArgs.hasArg(options::OPT_cl_unsafe_math_optimizations);
392   bool FastRelaxedMath = DriverArgs.hasArg(options::OPT_cl_fast_relaxed_math);
393   bool CorrectSqrt =
394       DriverArgs.hasArg(options::OPT_cl_fp32_correctly_rounded_divide_sqrt);
395 
396   // Add the OpenCL specific bitcode library.
397   CC1Args.push_back("-mlink-builtin-bitcode");
398   CC1Args.push_back(DriverArgs.MakeArgString(RocmInstallation.getOpenCLPath()));
399 
400   // Add the generic set of libraries.
401   RocmInstallation.addCommonBitcodeLibCC1Args(
402       DriverArgs, CC1Args, LibDeviceFile, Wave64, DAZ, FiniteOnly,
403       UnsafeMathOpt, FastRelaxedMath, CorrectSqrt);
404 }
405 
406 void RocmInstallationDetector::addCommonBitcodeLibCC1Args(
407     const llvm::opt::ArgList &DriverArgs, llvm::opt::ArgStringList &CC1Args,
408     StringRef LibDeviceFile, bool Wave64, bool DAZ, bool FiniteOnly,
409     bool UnsafeMathOpt, bool FastRelaxedMath, bool CorrectSqrt) const {
410   static const char LinkBitcodeFlag[] = "-mlink-builtin-bitcode";
411 
412   CC1Args.push_back(LinkBitcodeFlag);
413   CC1Args.push_back(DriverArgs.MakeArgString(getOCMLPath()));
414 
415   CC1Args.push_back(LinkBitcodeFlag);
416   CC1Args.push_back(DriverArgs.MakeArgString(getOCKLPath()));
417 
418   CC1Args.push_back(LinkBitcodeFlag);
419   CC1Args.push_back(DriverArgs.MakeArgString(getDenormalsAreZeroPath(DAZ)));
420 
421   CC1Args.push_back(LinkBitcodeFlag);
422   CC1Args.push_back(DriverArgs.MakeArgString(
423       getUnsafeMathPath(UnsafeMathOpt || FastRelaxedMath)));
424 
425   CC1Args.push_back(LinkBitcodeFlag);
426   CC1Args.push_back(DriverArgs.MakeArgString(
427       getFiniteOnlyPath(FiniteOnly || FastRelaxedMath)));
428 
429   CC1Args.push_back(LinkBitcodeFlag);
430   CC1Args.push_back(
431       DriverArgs.MakeArgString(getCorrectlyRoundedSqrtPath(CorrectSqrt)));
432 
433   CC1Args.push_back(LinkBitcodeFlag);
434   CC1Args.push_back(DriverArgs.MakeArgString(getWavefrontSize64Path(Wave64)));
435 
436   CC1Args.push_back(LinkBitcodeFlag);
437   CC1Args.push_back(DriverArgs.MakeArgString(LibDeviceFile));
438 }
439