1 //===--- Fuchsia.cpp - Fuchsia 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 "Fuchsia.h"
10 #include "CommonArgs.h"
11 #include "clang/Config/config.h"
12 #include "clang/Driver/Compilation.h"
13 #include "clang/Driver/Driver.h"
14 #include "clang/Driver/DriverDiagnostic.h"
15 #include "clang/Driver/Options.h"
16 #include "clang/Driver/SanitizerArgs.h"
17 #include "llvm/Option/ArgList.h"
18 #include "llvm/ProfileData/InstrProf.h"
19 #include "llvm/Support/FileSystem.h"
20 #include "llvm/Support/Path.h"
21 #include "llvm/Support/VirtualFileSystem.h"
22 
23 using namespace clang::driver;
24 using namespace clang::driver::toolchains;
25 using namespace clang::driver::tools;
26 using namespace clang;
27 using namespace llvm::opt;
28 
29 using tools::addMultilibFlag;
30 using tools::addPathIfExists;
31 
32 void fuchsia::Linker::ConstructJob(Compilation &C, const JobAction &JA,
33                                    const InputInfo &Output,
34                                    const InputInfoList &Inputs,
35                                    const ArgList &Args,
36                                    const char *LinkingOutput) const {
37   const toolchains::Fuchsia &ToolChain =
38       static_cast<const toolchains::Fuchsia &>(getToolChain());
39   const Driver &D = ToolChain.getDriver();
40 
41   ArgStringList CmdArgs;
42 
43   // Silence warning for "clang -g foo.o -o foo"
44   Args.ClaimAllArgs(options::OPT_g_Group);
45   // and "clang -emit-llvm foo.o -o foo"
46   Args.ClaimAllArgs(options::OPT_emit_llvm);
47   // and for "clang -w foo.o -o foo". Other warning options are already
48   // handled somewhere else.
49   Args.ClaimAllArgs(options::OPT_w);
50 
51   CmdArgs.push_back("-z");
52   CmdArgs.push_back("max-page-size=4096");
53 
54   CmdArgs.push_back("-z");
55   CmdArgs.push_back("now");
56 
57   const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
58   if (llvm::sys::path::filename(Exec).equals_lower("ld.lld") ||
59       llvm::sys::path::stem(Exec).equals_lower("ld.lld")) {
60     CmdArgs.push_back("-z");
61     CmdArgs.push_back("rodynamic");
62     CmdArgs.push_back("-z");
63     CmdArgs.push_back("separate-loadable-segments");
64     CmdArgs.push_back("--pack-dyn-relocs=relr");
65   }
66 
67   if (!D.SysRoot.empty())
68     CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
69 
70   if (!Args.hasArg(options::OPT_shared) && !Args.hasArg(options::OPT_r))
71     CmdArgs.push_back("-pie");
72 
73   if (Args.hasArg(options::OPT_rdynamic))
74     CmdArgs.push_back("-export-dynamic");
75 
76   if (Args.hasArg(options::OPT_s))
77     CmdArgs.push_back("-s");
78 
79   if (Args.hasArg(options::OPT_r)) {
80     CmdArgs.push_back("-r");
81   } else {
82     CmdArgs.push_back("--build-id");
83     CmdArgs.push_back("--hash-style=gnu");
84   }
85 
86   CmdArgs.push_back("--eh-frame-hdr");
87 
88   if (Args.hasArg(options::OPT_static))
89     CmdArgs.push_back("-Bstatic");
90   else if (Args.hasArg(options::OPT_shared))
91     CmdArgs.push_back("-shared");
92 
93   const SanitizerArgs &SanArgs = ToolChain.getSanitizerArgs();
94 
95   if (!Args.hasArg(options::OPT_shared)) {
96     std::string Dyld = D.DyldPrefix;
97     if (SanArgs.needsAsanRt() && SanArgs.needsSharedRt())
98       Dyld += "asan/";
99     if (SanArgs.needsHwasanRt() && SanArgs.needsSharedRt())
100       Dyld += "hwasan/";
101     if (SanArgs.needsTsanRt() && SanArgs.needsSharedRt())
102       Dyld += "tsan/";
103     Dyld += "ld.so.1";
104     CmdArgs.push_back("-dynamic-linker");
105     CmdArgs.push_back(Args.MakeArgString(Dyld));
106   }
107 
108   CmdArgs.push_back("-o");
109   CmdArgs.push_back(Output.getFilename());
110 
111   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
112     if (!Args.hasArg(options::OPT_shared)) {
113       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("Scrt1.o")));
114     }
115   }
116 
117   Args.AddAllArgs(CmdArgs, options::OPT_L);
118   Args.AddAllArgs(CmdArgs, options::OPT_u);
119 
120   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
121 
122   if (D.isUsingLTO()) {
123     assert(!Inputs.empty() && "Must have at least one input.");
124     addLTOOptions(ToolChain, Args, CmdArgs, Output, Inputs[0],
125                   D.getLTOMode() == LTOK_Thin);
126   }
127 
128   bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
129   bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
130   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
131   ToolChain.addProfileRTLibs(Args, CmdArgs);
132 
133   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
134     if (Args.hasArg(options::OPT_static))
135       CmdArgs.push_back("-Bdynamic");
136 
137     if (D.CCCIsCXX()) {
138       if (ToolChain.ShouldLinkCXXStdlib(Args)) {
139         bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
140                                    !Args.hasArg(options::OPT_static);
141         CmdArgs.push_back("--push-state");
142         CmdArgs.push_back("--as-needed");
143         if (OnlyLibstdcxxStatic)
144           CmdArgs.push_back("-Bstatic");
145         ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
146         if (OnlyLibstdcxxStatic)
147           CmdArgs.push_back("-Bdynamic");
148         CmdArgs.push_back("-lm");
149         CmdArgs.push_back("--pop-state");
150       }
151     }
152 
153     if (NeedsSanitizerDeps)
154       linkSanitizerRuntimeDeps(ToolChain, CmdArgs);
155 
156     if (NeedsXRayDeps)
157       linkXRayRuntimeDeps(ToolChain, CmdArgs);
158 
159     AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
160 
161     if (Args.hasArg(options::OPT_pthread) ||
162         Args.hasArg(options::OPT_pthreads))
163       CmdArgs.push_back("-lpthread");
164 
165     if (Args.hasArg(options::OPT_fsplit_stack))
166       CmdArgs.push_back("--wrap=pthread_create");
167 
168     if (!Args.hasArg(options::OPT_nolibc))
169       CmdArgs.push_back("-lc");
170   }
171 
172   C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
173                                          Exec, CmdArgs, Inputs, Output));
174 }
175 
176 /// Fuchsia - Fuchsia tool chain which can call as(1) and ld(1) directly.
177 
178 Fuchsia::Fuchsia(const Driver &D, const llvm::Triple &Triple,
179                  const ArgList &Args)
180     : ToolChain(D, Triple, Args) {
181   getProgramPaths().push_back(getDriver().getInstalledDir());
182   if (getDriver().getInstalledDir() != D.Dir)
183     getProgramPaths().push_back(D.Dir);
184 
185   addPathIfExists(D, getRuntimePath(), getLibraryPaths());
186 
187   addPathIfExists(D, getStdlibPath(), getFilePaths());
188 
189   if (!D.SysRoot.empty()) {
190     SmallString<128> P(D.SysRoot);
191     llvm::sys::path::append(P, "lib");
192     getFilePaths().push_back(std::string(P.str()));
193   }
194 
195   auto FilePaths = [&](const Multilib &M) -> std::vector<std::string> {
196     std::vector<std::string> FP;
197     SmallString<128> P(getStdlibPath());
198     llvm::sys::path::append(P, M.gccSuffix());
199     FP.push_back(std::string(P.str()));
200     return FP;
201   };
202 
203   Multilibs.push_back(Multilib());
204   // Use the noexcept variant with -fno-exceptions to avoid the extra overhead.
205   Multilibs.push_back(Multilib("noexcept", {}, {}, 1)
206                           .flag("-fexceptions")
207                           .flag("+fno-exceptions"));
208   // ASan has higher priority because we always want the instrumentated version.
209   Multilibs.push_back(Multilib("asan", {}, {}, 2)
210                           .flag("+fsanitize=address"));
211   // Use the asan+noexcept variant with ASan and -fno-exceptions.
212   Multilibs.push_back(Multilib("asan+noexcept", {}, {}, 3)
213                           .flag("+fsanitize=address")
214                           .flag("-fexceptions")
215                           .flag("+fno-exceptions"));
216   // HWASan has higher priority because we always want the instrumentated
217   // version.
218   Multilibs.push_back(
219       Multilib("hwasan", {}, {}, 4).flag("+fsanitize=hwaddress"));
220   // Use the hwasan+noexcept variant with HWASan and -fno-exceptions.
221   Multilibs.push_back(Multilib("hwasan+noexcept", {}, {}, 5)
222                           .flag("+fsanitize=hwaddress")
223                           .flag("-fexceptions")
224                           .flag("+fno-exceptions"));
225   // Use the relative vtables ABI.
226   // TODO: Remove these multilibs once relative vtables are enabled by default
227   // for Fuchsia.
228   Multilibs.push_back(Multilib("relative-vtables", {}, {}, 6)
229                           .flag("+fexperimental-relative-c++-abi-vtables"));
230   Multilibs.push_back(Multilib("relative-vtables+noexcept", {}, {}, 7)
231                           .flag("+fexperimental-relative-c++-abi-vtables")
232                           .flag("-fexceptions")
233                           .flag("+fno-exceptions"));
234   Multilibs.push_back(Multilib("relative-vtables+asan", {}, {}, 8)
235                           .flag("+fexperimental-relative-c++-abi-vtables")
236                           .flag("+fsanitize=address"));
237   Multilibs.push_back(Multilib("relative-vtables+asan+noexcept", {}, {}, 9)
238                           .flag("+fexperimental-relative-c++-abi-vtables")
239                           .flag("+fsanitize=address")
240                           .flag("-fexceptions")
241                           .flag("+fno-exceptions"));
242   Multilibs.push_back(Multilib("relative-vtables+hwasan", {}, {}, 10)
243                           .flag("+fexperimental-relative-c++-abi-vtables")
244                           .flag("+fsanitize=hwaddress"));
245   Multilibs.push_back(Multilib("relative-vtables+hwasan+noexcept", {}, {}, 11)
246                           .flag("+fexperimental-relative-c++-abi-vtables")
247                           .flag("+fsanitize=hwaddress")
248                           .flag("-fexceptions")
249                           .flag("+fno-exceptions"));
250 
251   Multilibs.FilterOut([&](const Multilib &M) {
252     std::vector<std::string> RD = FilePaths(M);
253     return std::all_of(RD.begin(), RD.end(), [&](std::string P) {
254       return !getVFS().exists(P);
255     });
256   });
257 
258   Multilib::flags_list Flags;
259   addMultilibFlag(
260       Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions, true),
261       "fexceptions", Flags);
262   addMultilibFlag(getSanitizerArgs().needsAsanRt(), "fsanitize=address", Flags);
263   addMultilibFlag(getSanitizerArgs().needsHwasanRt(), "fsanitize=hwaddress",
264                   Flags);
265 
266   addMultilibFlag(
267       Args.hasFlag(options::OPT_fexperimental_relative_cxx_abi_vtables,
268                    options::OPT_fno_experimental_relative_cxx_abi_vtables,
269                    /*default=*/false),
270       "fexperimental-relative-c++-abi-vtables", Flags);
271 
272   Multilibs.setFilePathsCallback(FilePaths);
273 
274   if (Multilibs.select(Flags, SelectedMultilib))
275     if (!SelectedMultilib.isDefault())
276       if (const auto &PathsCallback = Multilibs.filePathsCallback())
277         for (const auto &Path : PathsCallback(SelectedMultilib))
278           // Prepend the multilib path to ensure it takes the precedence.
279           getFilePaths().insert(getFilePaths().begin(), Path);
280 }
281 
282 /// Following the conventions in https://wiki.debian.org/Multiarch/Tuples,
283 /// we remove the vendor field to form the multiarch triple.
284 std::string Fuchsia::getMultiarchTriple(const Driver &D,
285                                         const llvm::Triple &TargetTriple,
286                                         StringRef SysRoot) const {
287     return (TargetTriple.getArchName() + "-" +
288             TargetTriple.getOSAndEnvironmentName()).str();
289 }
290 
291 std::string Fuchsia::ComputeEffectiveClangTriple(const ArgList &Args,
292                                                  types::ID InputType) const {
293   llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
294   return Triple.str();
295 }
296 
297 Tool *Fuchsia::buildLinker() const {
298   return new tools::fuchsia::Linker(*this);
299 }
300 
301 ToolChain::RuntimeLibType Fuchsia::GetRuntimeLibType(
302     const ArgList &Args) const {
303   if (Arg *A = Args.getLastArg(clang::driver::options::OPT_rtlib_EQ)) {
304     StringRef Value = A->getValue();
305     if (Value != "compiler-rt")
306       getDriver().Diag(clang::diag::err_drv_invalid_rtlib_name)
307           << A->getAsString(Args);
308   }
309 
310   return ToolChain::RLT_CompilerRT;
311 }
312 
313 ToolChain::CXXStdlibType
314 Fuchsia::GetCXXStdlibType(const ArgList &Args) const {
315   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
316     StringRef Value = A->getValue();
317     if (Value != "libc++")
318       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
319         << A->getAsString(Args);
320   }
321 
322   return ToolChain::CST_Libcxx;
323 }
324 
325 void Fuchsia::addClangTargetOptions(const ArgList &DriverArgs,
326                                     ArgStringList &CC1Args,
327                                     Action::OffloadKind) const {
328   if (!DriverArgs.hasFlag(options::OPT_fuse_init_array,
329                           options::OPT_fno_use_init_array, true))
330     CC1Args.push_back("-fno-use-init-array");
331 }
332 
333 void Fuchsia::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
334                                         ArgStringList &CC1Args) const {
335   const Driver &D = getDriver();
336 
337   if (DriverArgs.hasArg(options::OPT_nostdinc))
338     return;
339 
340   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
341     SmallString<128> P(D.ResourceDir);
342     llvm::sys::path::append(P, "include");
343     addSystemInclude(DriverArgs, CC1Args, P);
344   }
345 
346   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
347     return;
348 
349   // Check for configure-time C include directories.
350   StringRef CIncludeDirs(C_INCLUDE_DIRS);
351   if (CIncludeDirs != "") {
352     SmallVector<StringRef, 5> dirs;
353     CIncludeDirs.split(dirs, ":");
354     for (StringRef dir : dirs) {
355       StringRef Prefix =
356           llvm::sys::path::is_absolute(dir) ? "" : StringRef(D.SysRoot);
357       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
358     }
359     return;
360   }
361 
362   if (!D.SysRoot.empty()) {
363     SmallString<128> P(D.SysRoot);
364     llvm::sys::path::append(P, "include");
365     addExternCSystemInclude(DriverArgs, CC1Args, P.str());
366   }
367 }
368 
369 void Fuchsia::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
370                                            ArgStringList &CC1Args) const {
371   if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
372       DriverArgs.hasArg(options::OPT_nostdincxx))
373     return;
374 
375   switch (GetCXXStdlibType(DriverArgs)) {
376   case ToolChain::CST_Libcxx: {
377     SmallString<128> P(getDriver().Dir);
378     llvm::sys::path::append(P, "..", "include");
379     std::string Version = detectLibcxxVersion(P);
380     llvm::sys::path::append(P, "c++", Version);
381     addSystemInclude(DriverArgs, CC1Args, P.str());
382     break;
383   }
384 
385   default:
386     llvm_unreachable("invalid stdlib name");
387   }
388 }
389 
390 void Fuchsia::AddCXXStdlibLibArgs(const ArgList &Args,
391                                   ArgStringList &CmdArgs) const {
392   switch (GetCXXStdlibType(Args)) {
393   case ToolChain::CST_Libcxx:
394     CmdArgs.push_back("-lc++");
395     break;
396 
397   case ToolChain::CST_Libstdcxx:
398     llvm_unreachable("invalid stdlib name");
399   }
400 }
401 
402 SanitizerMask Fuchsia::getSupportedSanitizers() const {
403   SanitizerMask Res = ToolChain::getSupportedSanitizers();
404   Res |= SanitizerKind::Address;
405   Res |= SanitizerKind::HWAddress;
406   Res |= SanitizerKind::PointerCompare;
407   Res |= SanitizerKind::PointerSubtract;
408   Res |= SanitizerKind::Fuzzer;
409   Res |= SanitizerKind::FuzzerNoLink;
410   Res |= SanitizerKind::Leak;
411   Res |= SanitizerKind::SafeStack;
412   Res |= SanitizerKind::Scudo;
413   Res |= SanitizerKind::Thread;
414   return Res;
415 }
416 
417 SanitizerMask Fuchsia::getDefaultSanitizers() const {
418   SanitizerMask Res;
419   switch (getTriple().getArch()) {
420   case llvm::Triple::aarch64:
421     Res |= SanitizerKind::ShadowCallStack;
422     break;
423   case llvm::Triple::x86_64:
424     Res |= SanitizerKind::SafeStack;
425     break;
426   default:
427     // TODO: Enable SafeStack on RISC-V once tested.
428     break;
429   }
430   return Res;
431 }
432 
433 void Fuchsia::addProfileRTLibs(const llvm::opt::ArgList &Args,
434                                llvm::opt::ArgStringList &CmdArgs) const {
435   // Add linker option -u__llvm_profile_runtime to cause runtime
436   // initialization module to be linked in.
437   if (needsProfileRT(Args))
438     CmdArgs.push_back(Args.MakeArgString(
439         Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
440   ToolChain::addProfileRTLibs(Args, CmdArgs);
441 }
442