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

source code of clang/lib/Driver/ToolChains/Arch/X86.cpp