1//===--- X86.cpp - X86 Helpers for Tools ------------------------*- 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 "X86.h"
10#include "clang/Driver/Driver.h"
11#include "clang/Driver/Options.h"
12#include "llvm/ADT/StringExtras.h"
13#include "llvm/ADT/StringMap.h"
14#include "llvm/Option/ArgList.h"
15#include "llvm/TargetParser/Host.h"
16
17using namespace clang::driver;
18using namespace clang::driver::tools;
19using namespace clang;
20using namespace llvm::opt;
21
22std::string x86::getX86TargetCPU(const Driver &D, const ArgList &Args,
23 const llvm::Triple &Triple) {
24 if (const Arg *A = Args.getLastArg(Ids: clang::driver::options::OPT_march_EQ)) {
25 StringRef CPU = A->getValue();
26 if (CPU != "native")
27 return std::string(CPU);
28
29 // FIXME: Reject attempts to use -march=native unless the target matches
30 // the host.
31 CPU = llvm::sys::getHostCPUName();
32 if (!CPU.empty() && CPU != "generic")
33 return std::string(CPU);
34 }
35
36 if (const Arg *A = Args.getLastArg(Ids: options::OPT__SLASH_arch)) {
37 // Mapping built by looking at lib/Basic's X86TargetInfo::initFeatureMap().
38 // The keys are case-sensitive; this matches link.exe.
39 // 32-bit and 64-bit /arch: flags.
40 llvm::StringMap<StringRef> ArchMap({
41 {"AVX", "sandybridge"},
42 {"AVX2", "haswell"},
43 {"AVX512F", "knl"},
44 {"AVX512", "skylake-avx512"},
45 });
46 if (Triple.getArch() == llvm::Triple::x86) {
47 // 32-bit-only /arch: flags.
48 ArchMap.insert(List: {
49 {"IA32", "i386"},
50 {"SSE", "pentium3"},
51 {"SSE2", "pentium4"},
52 });
53 }
54 StringRef CPU = ArchMap.lookup(Key: A->getValue());
55 if (CPU.empty()) {
56 std::vector<StringRef> ValidArchs{ArchMap.keys().begin(),
57 ArchMap.keys().end()};
58 sort(C&: ValidArchs);
59 D.Diag(DiagID: diag::warn_drv_invalid_arch_name_with_suggestion)
60 << A->getValue() << (Triple.getArch() == llvm::Triple::x86)
61 << join(R&: ValidArchs, Separator: ", ");
62 }
63 return std::string(CPU);
64 }
65
66 // Select the default CPU if none was given (or detection failed).
67
68 if (!Triple.isX86())
69 return ""; // This routine is only handling x86 targets.
70
71 bool Is64Bit = Triple.getArch() == llvm::Triple::x86_64;
72
73 // FIXME: Need target hooks.
74 if (Triple.isOSDarwin()) {
75 if (Triple.getArchName() == "x86_64h")
76 return "core-avx2";
77 // macosx10.12 drops support for all pre-Penryn Macs.
78 // Simulators can still run on 10.11 though, like Xcode.
79 if (Triple.isMacOSX() && !Triple.isOSVersionLT(Major: 10, Minor: 12))
80 return "penryn";
81
82 if (Triple.isDriverKit())
83 return "nehalem";
84
85 // The oldest x86_64 Macs have core2/Merom; the oldest x86 Macs have Yonah.
86 return Is64Bit ? "core2" : "yonah";
87 }
88
89 // Set up default CPU name for PS4/PS5 compilers.
90 if (Triple.isPS4())
91 return "btver2";
92 if (Triple.isPS5())
93 return "znver2";
94
95 // On Android use targets compatible with gcc
96 if (Triple.isAndroid())
97 return Is64Bit ? "x86-64" : "i686";
98
99 // Everything else goes to x86-64 in 64-bit mode.
100 if (Is64Bit)
101 return "x86-64";
102
103 switch (Triple.getOS()) {
104 case llvm::Triple::NetBSD:
105 return "i486";
106 case llvm::Triple::Haiku:
107 case llvm::Triple::OpenBSD:
108 return "i586";
109 case llvm::Triple::FreeBSD:
110 return "i686";
111 default:
112 // Fallback to p4.
113 return "pentium4";
114 }
115}
116
117void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
118 const ArgList &Args,
119 std::vector<StringRef> &Features) {
120 // Claim and report unsupported -mabi=. Note: we don't support "sysv_abi" or
121 // "ms_abi" as default function attributes.
122 if (const Arg *A = Args.getLastArg(Ids: clang::driver::options::OPT_mabi_EQ)) {
123 StringRef DefaultAbi =
124 (Triple.isOSWindows() || Triple.isUEFI()) ? "ms" : "sysv";
125 if (A->getValue() != DefaultAbi)
126 D.Diag(DiagID: diag::err_drv_unsupported_opt_for_target)
127 << A->getSpelling() << Triple.getTriple();
128 }
129
130 // If -march=native, autodetect the feature list.
131 if (const Arg *A = Args.getLastArg(Ids: clang::driver::options::OPT_march_EQ)) {
132 if (StringRef(A->getValue()) == "native") {
133 for (auto &F : llvm::sys::getHostCPUFeatures())
134 Features.push_back(
135 x: Args.MakeArgString(Str: (F.second ? "+" : "-") + F.first()));
136 }
137 }
138
139 if (Triple.getArchName() == "x86_64h") {
140 // x86_64h implies quite a few of the more modern subtarget features
141 // for Haswell class CPUs, but not all of them. Opt-out of a few.
142 Features.push_back(x: "-rdrnd");
143 Features.push_back(x: "-aes");
144 Features.push_back(x: "-pclmul");
145 Features.push_back(x: "-rtm");
146 Features.push_back(x: "-fsgsbase");
147 }
148
149 const llvm::Triple::ArchType ArchType = Triple.getArch();
150 // Add features to be compatible with gcc for Android.
151 if (Triple.isAndroid()) {
152 if (ArchType == llvm::Triple::x86_64) {
153 Features.push_back(x: "+sse4.2");
154 Features.push_back(x: "+popcnt");
155 Features.push_back(x: "+cx16");
156 } else
157 Features.push_back(x: "+ssse3");
158 }
159
160 // Translate the high level `-mretpoline` flag to the specific target feature
161 // flags. We also detect if the user asked for retpoline external thunks but
162 // failed to ask for retpolines themselves (through any of the different
163 // flags). This is a bit hacky but keeps existing usages working. We should
164 // consider deprecating this and instead warn if the user requests external
165 // retpoline thunks and *doesn't* request some form of retpolines.
166 auto SpectreOpt = clang::driver::options::ID::OPT_INVALID;
167 if (Args.hasArgNoClaim(Ids: options::OPT_mretpoline, Ids: options::OPT_mno_retpoline,
168 Ids: options::OPT_mspeculative_load_hardening,
169 Ids: options::OPT_mno_speculative_load_hardening)) {
170 if (Args.hasFlag(Pos: options::OPT_mretpoline, Neg: options::OPT_mno_retpoline,
171 Default: false)) {
172 Features.push_back(x: "+retpoline-indirect-calls");
173 Features.push_back(x: "+retpoline-indirect-branches");
174 SpectreOpt = options::OPT_mretpoline;
175 } else if (Args.hasFlag(Pos: options::OPT_mspeculative_load_hardening,
176 Neg: options::OPT_mno_speculative_load_hardening,
177 Default: false)) {
178 // On x86, speculative load hardening relies on at least using retpolines
179 // for indirect calls.
180 Features.push_back(x: "+retpoline-indirect-calls");
181 SpectreOpt = options::OPT_mspeculative_load_hardening;
182 }
183 } else if (Args.hasFlag(Pos: options::OPT_mretpoline_external_thunk,
184 Neg: options::OPT_mno_retpoline_external_thunk, Default: false)) {
185 // FIXME: Add a warning about failing to specify `-mretpoline` and
186 // eventually switch to an error here.
187 Features.push_back(x: "+retpoline-indirect-calls");
188 Features.push_back(x: "+retpoline-indirect-branches");
189 SpectreOpt = options::OPT_mretpoline_external_thunk;
190 }
191
192 auto LVIOpt = clang::driver::options::ID::OPT_INVALID;
193 if (Args.hasFlag(Pos: options::OPT_mlvi_hardening, Neg: options::OPT_mno_lvi_hardening,
194 Default: false)) {
195 Features.push_back(x: "+lvi-load-hardening");
196 Features.push_back(x: "+lvi-cfi"); // load hardening implies CFI protection
197 LVIOpt = options::OPT_mlvi_hardening;
198 } else if (Args.hasFlag(Pos: options::OPT_mlvi_cfi, Neg: options::OPT_mno_lvi_cfi,
199 Default: false)) {
200 Features.push_back(x: "+lvi-cfi");
201 LVIOpt = options::OPT_mlvi_cfi;
202 }
203
204 if (Args.hasFlag(Pos: options::OPT_m_seses, Neg: options::OPT_mno_seses, Default: false)) {
205 if (LVIOpt == options::OPT_mlvi_hardening)
206 D.Diag(DiagID: diag::err_drv_argument_not_allowed_with)
207 << D.getOpts().getOptionName(id: options::OPT_mlvi_hardening)
208 << D.getOpts().getOptionName(id: options::OPT_m_seses);
209
210 if (SpectreOpt != clang::driver::options::ID::OPT_INVALID)
211 D.Diag(DiagID: diag::err_drv_argument_not_allowed_with)
212 << D.getOpts().getOptionName(id: SpectreOpt)
213 << D.getOpts().getOptionName(id: options::OPT_m_seses);
214
215 Features.push_back(x: "+seses");
216 if (!Args.hasArg(Ids: options::OPT_mno_lvi_cfi)) {
217 Features.push_back(x: "+lvi-cfi");
218 LVIOpt = options::OPT_mlvi_cfi;
219 }
220 }
221
222 if (SpectreOpt != clang::driver::options::ID::OPT_INVALID &&
223 LVIOpt != clang::driver::options::ID::OPT_INVALID) {
224 D.Diag(DiagID: diag::err_drv_argument_not_allowed_with)
225 << D.getOpts().getOptionName(id: SpectreOpt)
226 << D.getOpts().getOptionName(id: LVIOpt);
227 }
228
229 for (const Arg *A : Args.filtered(Ids: options::OPT_m_x86_AVX10_Features_Group)) {
230 StringRef Name = A->getOption().getName();
231 A->claim();
232
233 // Skip over "-m".
234 assert(Name.starts_with("m") && "Invalid feature name.");
235 Name = Name.substr(Start: 1);
236
237 bool IsNegative = Name.consume_front(Prefix: "no-");
238
239 StringRef Version, Width;
240 std::tie(args&: Version, args&: Width) = Name.substr(Start: 6).split(Separator: '-');
241 assert(Name.starts_with("avx10.") && "Invalid AVX10 feature name.");
242 assert((Version == "1" || Version == "2") && "Invalid AVX10 feature name.");
243
244 if (Width == "") {
245 if (IsNegative)
246 Features.push_back(x: Args.MakeArgString(Str: "-" + Name + "-256"));
247 else
248 Features.push_back(x: Args.MakeArgString(Str: "+" + Name + "-512"));
249 } else {
250 if (Width == "512")
251 D.Diag(DiagID: diag::warn_drv_deprecated_arg) << Name << 1 << Name.drop_back(N: 4);
252 else if (Width == "256")
253 D.Diag(DiagID: diag::warn_drv_deprecated_custom)
254 << Name
255 << "no alternative argument provided because "
256 "AVX10/256 is not supported and will be removed";
257 else
258 assert((Width == "256" || Width == "512") && "Invalid vector length.");
259 Features.push_back(x: Args.MakeArgString(Str: (IsNegative ? "-" : "+") + Name));
260 }
261 }
262
263 // Now add any that the user explicitly requested on the command line,
264 // which may override the defaults.
265 for (const Arg *A : Args.filtered(Ids: options::OPT_m_x86_Features_Group,
266 Ids: options::OPT_mgeneral_regs_only)) {
267 StringRef Name = A->getOption().getName();
268 A->claim();
269
270 // Skip over "-m".
271 assert(Name.starts_with("m") && "Invalid feature name.");
272 Name = Name.substr(Start: 1);
273
274 // Replace -mgeneral-regs-only with -x87, -mmx, -sse
275 if (A->getOption().getID() == options::OPT_mgeneral_regs_only) {
276 Features.insert(position: Features.end(), l: {"-x87", "-mmx", "-sse"});
277 continue;
278 }
279
280 bool IsNegative = Name.starts_with(Prefix: "no-");
281
282 bool Not64Bit = ArchType != llvm::Triple::x86_64;
283 if (Not64Bit && Name == "uintr")
284 D.Diag(DiagID: diag::err_drv_unsupported_opt_for_target)
285 << A->getSpelling() << Triple.getTriple();
286
287 if (A->getOption().matches(ID: options::OPT_mevex512) ||
288 A->getOption().matches(ID: options::OPT_mno_evex512))
289 D.Diag(DiagID: diag::warn_drv_deprecated_custom)
290 << Name
291 << "no alternative argument provided because "
292 "AVX10/256 is not supported and will be removed";
293
294 if (A->getOption().matches(ID: options::OPT_mapx_features_EQ) ||
295 A->getOption().matches(ID: options::OPT_mno_apx_features_EQ)) {
296
297 if (Not64Bit && !IsNegative)
298 D.Diag(DiagID: diag::err_drv_unsupported_opt_for_target)
299 << StringRef(A->getSpelling().str() + "|-mapxf")
300 << Triple.getTriple();
301
302 for (StringRef Value : A->getValues()) {
303 if (Value != "egpr" && Value != "push2pop2" && Value != "ppx" &&
304 Value != "ndd" && Value != "ccmp" && Value != "nf" &&
305 Value != "cf" && Value != "zu")
306 D.Diag(DiagID: clang::diag::err_drv_unsupported_option_argument)
307 << A->getSpelling() << Value;
308
309 Features.push_back(
310 x: Args.MakeArgString(Str: (IsNegative ? "-" : "+") + Value));
311 }
312 continue;
313 }
314 if (IsNegative)
315 Name = Name.substr(Start: 3);
316 Features.push_back(x: Args.MakeArgString(Str: (IsNegative ? "-" : "+") + Name));
317 }
318
319 // Enable/disable straight line speculation hardening.
320 if (Arg *A = Args.getLastArg(Ids: options::OPT_mharden_sls_EQ)) {
321 StringRef Scope = A->getValue();
322 if (Scope == "all") {
323 Features.push_back(x: "+harden-sls-ijmp");
324 Features.push_back(x: "+harden-sls-ret");
325 } else if (Scope == "return") {
326 Features.push_back(x: "+harden-sls-ret");
327 } else if (Scope == "indirect-jmp") {
328 Features.push_back(x: "+harden-sls-ijmp");
329 } else if (Scope != "none") {
330 D.Diag(DiagID: diag::err_drv_unsupported_option_argument)
331 << A->getSpelling() << Scope;
332 }
333 }
334
335 // -mno-gather, -mno-scatter support
336 if (Args.hasArg(Ids: options::OPT_mno_gather))
337 Features.push_back(x: "+prefer-no-gather");
338 if (Args.hasArg(Ids: options::OPT_mno_scatter))
339 Features.push_back(x: "+prefer-no-scatter");
340 if (Args.hasArg(Ids: options::OPT_mapx_inline_asm_use_gpr32))
341 Features.push_back(x: "+inline-asm-use-gpr32");
342
343 // Warn for removed 3dnow support
344 if (const Arg *A =
345 Args.getLastArg(Ids: options::OPT_m3dnowa, Ids: options::OPT_mno_3dnowa,
346 Ids: options::OPT_mno_3dnow)) {
347 if (A->getOption().matches(ID: options::OPT_m3dnowa))
348 D.Diag(DiagID: diag::warn_drv_clang_unsupported) << A->getAsString(Args);
349 }
350 if (const Arg *A =
351 Args.getLastArg(Ids: options::OPT_m3dnow, Ids: options::OPT_mno_3dnow)) {
352 if (A->getOption().matches(ID: options::OPT_m3dnow))
353 D.Diag(DiagID: diag::warn_drv_clang_unsupported) << A->getAsString(Args);
354 }
355}
356