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/Support/FileSystem.h"
19 #include "llvm/Support/Path.h"
20 #include "llvm/Support/VirtualFileSystem.h"
21 
22 using namespace clang::driver;
23 using namespace clang::driver::toolchains;
24 using namespace clang::driver::tools;
25 using namespace clang;
26 using namespace llvm::opt;
27 
28 using tools::addMultilibFlag;
29 
30 void fuchsia::Linker::ConstructJob(Compilation &C, const JobAction &JA,
31                                    const InputInfo &Output,
32                                    const InputInfoList &Inputs,
33                                    const ArgList &Args,
34                                    const char *LinkingOutput) const {
35   const toolchains::Fuchsia &ToolChain =
36       static_cast<const toolchains::Fuchsia &>(getToolChain());
37   const Driver &D = ToolChain.getDriver();
38 
39   ArgStringList CmdArgs;
40 
41   // Silence warning for "clang -g foo.o -o foo"
42   Args.ClaimAllArgs(options::OPT_g_Group);
43   // and "clang -emit-llvm foo.o -o foo"
44   Args.ClaimAllArgs(options::OPT_emit_llvm);
45   // and for "clang -w foo.o -o foo". Other warning options are already
46   // handled somewhere else.
47   Args.ClaimAllArgs(options::OPT_w);
48 
49   CmdArgs.push_back("-z");
50   CmdArgs.push_back("max-page-size=4096");
51 
52   CmdArgs.push_back("-z");
53   CmdArgs.push_back("now");
54 
55   const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
56   if (llvm::sys::path::filename(Exec).equals_lower("ld.lld") ||
57       llvm::sys::path::stem(Exec).equals_lower("ld.lld")) {
58     CmdArgs.push_back("-z");
59     CmdArgs.push_back("rodynamic");
60     CmdArgs.push_back("-z");
61     CmdArgs.push_back("separate-loadable-segments");
62     CmdArgs.push_back("--pack-dyn-relocs=relr");
63   }
64 
65   if (!D.SysRoot.empty())
66     CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
67 
68   if (!Args.hasArg(options::OPT_shared) && !Args.hasArg(options::OPT_r))
69     CmdArgs.push_back("-pie");
70 
71   if (Args.hasArg(options::OPT_rdynamic))
72     CmdArgs.push_back("-export-dynamic");
73 
74   if (Args.hasArg(options::OPT_s))
75     CmdArgs.push_back("-s");
76 
77   if (Args.hasArg(options::OPT_r)) {
78     CmdArgs.push_back("-r");
79   } else {
80     CmdArgs.push_back("--build-id");
81     CmdArgs.push_back("--hash-style=gnu");
82   }
83 
84   CmdArgs.push_back("--eh-frame-hdr");
85 
86   if (Args.hasArg(options::OPT_static))
87     CmdArgs.push_back("-Bstatic");
88   else if (Args.hasArg(options::OPT_shared))
89     CmdArgs.push_back("-shared");
90 
91   const SanitizerArgs &SanArgs = ToolChain.getSanitizerArgs();
92 
93   if (!Args.hasArg(options::OPT_shared)) {
94     std::string Dyld = D.DyldPrefix;
95     if (SanArgs.needsAsanRt() && SanArgs.needsSharedRt())
96       Dyld += "asan/";
97     Dyld += "ld.so.1";
98     CmdArgs.push_back("-dynamic-linker");
99     CmdArgs.push_back(Args.MakeArgString(Dyld));
100   }
101 
102   CmdArgs.push_back("-o");
103   CmdArgs.push_back(Output.getFilename());
104 
105   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
106     if (!Args.hasArg(options::OPT_shared)) {
107       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("Scrt1.o")));
108     }
109   }
110 
111   Args.AddAllArgs(CmdArgs, options::OPT_L);
112   Args.AddAllArgs(CmdArgs, options::OPT_u);
113 
114   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
115 
116   if (D.isUsingLTO()) {
117     assert(!Inputs.empty() && "Must have at least one input.");
118     addLTOOptions(ToolChain, Args, CmdArgs, Output, Inputs[0],
119                   D.getLTOMode() == LTOK_Thin);
120   }
121 
122   bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
123   bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
124   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
125   ToolChain.addProfileRTLibs(Args, CmdArgs);
126 
127   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
128     if (Args.hasArg(options::OPT_static))
129       CmdArgs.push_back("-Bdynamic");
130 
131     if (D.CCCIsCXX()) {
132       if (ToolChain.ShouldLinkCXXStdlib(Args)) {
133         bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
134                                    !Args.hasArg(options::OPT_static);
135         CmdArgs.push_back("--push-state");
136         CmdArgs.push_back("--as-needed");
137         if (OnlyLibstdcxxStatic)
138           CmdArgs.push_back("-Bstatic");
139         ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
140         if (OnlyLibstdcxxStatic)
141           CmdArgs.push_back("-Bdynamic");
142         CmdArgs.push_back("-lm");
143         CmdArgs.push_back("--pop-state");
144       }
145     }
146 
147     if (NeedsSanitizerDeps)
148       linkSanitizerRuntimeDeps(ToolChain, CmdArgs);
149 
150     if (NeedsXRayDeps)
151       linkXRayRuntimeDeps(ToolChain, CmdArgs);
152 
153     AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
154 
155     if (Args.hasArg(options::OPT_pthread) ||
156         Args.hasArg(options::OPT_pthreads))
157       CmdArgs.push_back("-lpthread");
158 
159     if (Args.hasArg(options::OPT_fsplit_stack))
160       CmdArgs.push_back("--wrap=pthread_create");
161 
162     if (!Args.hasArg(options::OPT_nolibc))
163       CmdArgs.push_back("-lc");
164   }
165 
166   C.addCommand(std::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
167 }
168 
169 /// Fuchsia - Fuchsia tool chain which can call as(1) and ld(1) directly.
170 
171 Fuchsia::Fuchsia(const Driver &D, const llvm::Triple &Triple,
172                  const ArgList &Args)
173     : ToolChain(D, Triple, Args) {
174   getProgramPaths().push_back(getDriver().getInstalledDir());
175   if (getDriver().getInstalledDir() != D.Dir)
176     getProgramPaths().push_back(D.Dir);
177 
178   if (!D.SysRoot.empty()) {
179     SmallString<128> P(D.SysRoot);
180     llvm::sys::path::append(P, "lib");
181     getFilePaths().push_back(std::string(P.str()));
182   }
183 
184   auto FilePaths = [&](const Multilib &M) -> std::vector<std::string> {
185     std::vector<std::string> FP;
186     if (D.CCCIsCXX()) {
187       if (auto CXXStdlibPath = getCXXStdlibPath()) {
188         SmallString<128> P(*CXXStdlibPath);
189         llvm::sys::path::append(P, M.gccSuffix());
190         FP.push_back(std::string(P.str()));
191       }
192     }
193     return FP;
194   };
195 
196   Multilibs.push_back(Multilib());
197   // Use the noexcept variant with -fno-exceptions to avoid the extra overhead.
198   Multilibs.push_back(Multilib("noexcept", {}, {}, 1)
199                           .flag("-fexceptions")
200                           .flag("+fno-exceptions"));
201   // ASan has higher priority because we always want the instrumentated version.
202   Multilibs.push_back(Multilib("asan", {}, {}, 2)
203                           .flag("+fsanitize=address"));
204   // Use the asan+noexcept variant with ASan and -fno-exceptions.
205   Multilibs.push_back(Multilib("asan+noexcept", {}, {}, 3)
206                           .flag("+fsanitize=address")
207                           .flag("-fexceptions")
208                           .flag("+fno-exceptions"));
209   Multilibs.FilterOut([&](const Multilib &M) {
210     std::vector<std::string> RD = FilePaths(M);
211     return std::all_of(RD.begin(), RD.end(), [&](std::string P) {
212       return !getVFS().exists(P);
213     });
214   });
215 
216   Multilib::flags_list Flags;
217   addMultilibFlag(
218       Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions, true),
219       "fexceptions", Flags);
220   addMultilibFlag(getSanitizerArgs().needsAsanRt(), "fsanitize=address", Flags);
221   Multilibs.setFilePathsCallback(FilePaths);
222 
223   if (Multilibs.select(Flags, SelectedMultilib))
224     if (!SelectedMultilib.isDefault())
225       if (const auto &PathsCallback = Multilibs.filePathsCallback())
226         for (const auto &Path : PathsCallback(SelectedMultilib))
227           // Prepend the multilib path to ensure it takes the precedence.
228           getFilePaths().insert(getFilePaths().begin(), Path);
229 }
230 
231 std::string Fuchsia::ComputeEffectiveClangTriple(const ArgList &Args,
232                                                  types::ID InputType) const {
233   llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
234   return Triple.str();
235 }
236 
237 Tool *Fuchsia::buildLinker() const {
238   return new tools::fuchsia::Linker(*this);
239 }
240 
241 ToolChain::RuntimeLibType Fuchsia::GetRuntimeLibType(
242     const ArgList &Args) const {
243   if (Arg *A = Args.getLastArg(clang::driver::options::OPT_rtlib_EQ)) {
244     StringRef Value = A->getValue();
245     if (Value != "compiler-rt")
246       getDriver().Diag(clang::diag::err_drv_invalid_rtlib_name)
247           << A->getAsString(Args);
248   }
249 
250   return ToolChain::RLT_CompilerRT;
251 }
252 
253 ToolChain::CXXStdlibType
254 Fuchsia::GetCXXStdlibType(const ArgList &Args) const {
255   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
256     StringRef Value = A->getValue();
257     if (Value != "libc++")
258       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
259         << A->getAsString(Args);
260   }
261 
262   return ToolChain::CST_Libcxx;
263 }
264 
265 void Fuchsia::addClangTargetOptions(const ArgList &DriverArgs,
266                                     ArgStringList &CC1Args,
267                                     Action::OffloadKind) const {
268   if (!DriverArgs.hasFlag(options::OPT_fuse_init_array,
269                           options::OPT_fno_use_init_array, true))
270     CC1Args.push_back("-fno-use-init-array");
271 }
272 
273 void Fuchsia::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
274                                         ArgStringList &CC1Args) const {
275   const Driver &D = getDriver();
276 
277   if (DriverArgs.hasArg(options::OPT_nostdinc))
278     return;
279 
280   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
281     SmallString<128> P(D.ResourceDir);
282     llvm::sys::path::append(P, "include");
283     addSystemInclude(DriverArgs, CC1Args, P);
284   }
285 
286   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
287     return;
288 
289   // Check for configure-time C include directories.
290   StringRef CIncludeDirs(C_INCLUDE_DIRS);
291   if (CIncludeDirs != "") {
292     SmallVector<StringRef, 5> dirs;
293     CIncludeDirs.split(dirs, ":");
294     for (StringRef dir : dirs) {
295       StringRef Prefix =
296           llvm::sys::path::is_absolute(dir) ? "" : StringRef(D.SysRoot);
297       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
298     }
299     return;
300   }
301 
302   if (!D.SysRoot.empty()) {
303     SmallString<128> P(D.SysRoot);
304     llvm::sys::path::append(P, "include");
305     addExternCSystemInclude(DriverArgs, CC1Args, P.str());
306   }
307 }
308 
309 void Fuchsia::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
310                                            ArgStringList &CC1Args) const {
311   if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
312       DriverArgs.hasArg(options::OPT_nostdincxx))
313     return;
314 
315   switch (GetCXXStdlibType(DriverArgs)) {
316   case ToolChain::CST_Libcxx: {
317     SmallString<128> P(getDriver().Dir);
318     llvm::sys::path::append(P, "..", "include", "c++", "v1");
319     addSystemInclude(DriverArgs, CC1Args, P.str());
320     break;
321   }
322 
323   default:
324     llvm_unreachable("invalid stdlib name");
325   }
326 }
327 
328 void Fuchsia::AddCXXStdlibLibArgs(const ArgList &Args,
329                                   ArgStringList &CmdArgs) const {
330   switch (GetCXXStdlibType(Args)) {
331   case ToolChain::CST_Libcxx:
332     CmdArgs.push_back("-lc++");
333     break;
334 
335   case ToolChain::CST_Libstdcxx:
336     llvm_unreachable("invalid stdlib name");
337   }
338 }
339 
340 SanitizerMask Fuchsia::getSupportedSanitizers() const {
341   SanitizerMask Res = ToolChain::getSupportedSanitizers();
342   Res |= SanitizerKind::Address;
343   Res |= SanitizerKind::PointerCompare;
344   Res |= SanitizerKind::PointerSubtract;
345   Res |= SanitizerKind::Fuzzer;
346   Res |= SanitizerKind::FuzzerNoLink;
347   Res |= SanitizerKind::Leak;
348   Res |= SanitizerKind::SafeStack;
349   Res |= SanitizerKind::Scudo;
350   return Res;
351 }
352 
353 SanitizerMask Fuchsia::getDefaultSanitizers() const {
354   SanitizerMask Res;
355   switch (getTriple().getArch()) {
356   case llvm::Triple::aarch64:
357     Res |= SanitizerKind::ShadowCallStack;
358     break;
359   case llvm::Triple::x86_64:
360     Res |= SanitizerKind::SafeStack;
361     break;
362   default:
363     // TODO: Enable SafeStack on RISC-V once tested.
364     break;
365   }
366   return Res;
367 }
368