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