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     Dyld += "ld.so.1";
99     CmdArgs.push_back("-dynamic-linker");
100     CmdArgs.push_back(Args.MakeArgString(Dyld));
101   }
102 
103   CmdArgs.push_back("-o");
104   CmdArgs.push_back(Output.getFilename());
105 
106   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
107     if (!Args.hasArg(options::OPT_shared)) {
108       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("Scrt1.o")));
109     }
110   }
111 
112   Args.AddAllArgs(CmdArgs, options::OPT_L);
113   Args.AddAllArgs(CmdArgs, options::OPT_u);
114 
115   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
116 
117   if (D.isUsingLTO()) {
118     assert(!Inputs.empty() && "Must have at least one input.");
119     addLTOOptions(ToolChain, Args, CmdArgs, Output, Inputs[0],
120                   D.getLTOMode() == LTOK_Thin);
121   }
122 
123   bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
124   bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
125   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
126   ToolChain.addProfileRTLibs(Args, CmdArgs);
127 
128   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
129     if (Args.hasArg(options::OPT_static))
130       CmdArgs.push_back("-Bdynamic");
131 
132     if (D.CCCIsCXX()) {
133       if (ToolChain.ShouldLinkCXXStdlib(Args)) {
134         bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
135                                    !Args.hasArg(options::OPT_static);
136         CmdArgs.push_back("--push-state");
137         CmdArgs.push_back("--as-needed");
138         if (OnlyLibstdcxxStatic)
139           CmdArgs.push_back("-Bstatic");
140         ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
141         if (OnlyLibstdcxxStatic)
142           CmdArgs.push_back("-Bdynamic");
143         CmdArgs.push_back("-lm");
144         CmdArgs.push_back("--pop-state");
145       }
146     }
147 
148     if (NeedsSanitizerDeps)
149       linkSanitizerRuntimeDeps(ToolChain, CmdArgs);
150 
151     if (NeedsXRayDeps)
152       linkXRayRuntimeDeps(ToolChain, CmdArgs);
153 
154     AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
155 
156     if (Args.hasArg(options::OPT_pthread) ||
157         Args.hasArg(options::OPT_pthreads))
158       CmdArgs.push_back("-lpthread");
159 
160     if (Args.hasArg(options::OPT_fsplit_stack))
161       CmdArgs.push_back("--wrap=pthread_create");
162 
163     if (!Args.hasArg(options::OPT_nolibc))
164       CmdArgs.push_back("-lc");
165   }
166 
167   C.addCommand(std::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
168 }
169 
170 /// Fuchsia - Fuchsia tool chain which can call as(1) and ld(1) directly.
171 
172 Fuchsia::Fuchsia(const Driver &D, const llvm::Triple &Triple,
173                  const ArgList &Args)
174     : ToolChain(D, Triple, Args) {
175   getProgramPaths().push_back(getDriver().getInstalledDir());
176   if (getDriver().getInstalledDir() != D.Dir)
177     getProgramPaths().push_back(D.Dir);
178 
179   if (!D.SysRoot.empty()) {
180     SmallString<128> P(D.SysRoot);
181     llvm::sys::path::append(P, "lib");
182     getFilePaths().push_back(std::string(P.str()));
183   }
184 
185   auto FilePaths = [&](const Multilib &M) -> std::vector<std::string> {
186     std::vector<std::string> FP;
187     if (D.CCCIsCXX()) {
188       if (auto CXXStdlibPath = getCXXStdlibPath()) {
189         SmallString<128> P(*CXXStdlibPath);
190         llvm::sys::path::append(P, M.gccSuffix());
191         FP.push_back(std::string(P.str()));
192       }
193     }
194     return FP;
195   };
196 
197   Multilibs.push_back(Multilib());
198   // Use the noexcept variant with -fno-exceptions to avoid the extra overhead.
199   Multilibs.push_back(Multilib("noexcept", {}, {}, 1)
200                           .flag("-fexceptions")
201                           .flag("+fno-exceptions"));
202   // ASan has higher priority because we always want the instrumentated version.
203   Multilibs.push_back(Multilib("asan", {}, {}, 2)
204                           .flag("+fsanitize=address"));
205   // Use the asan+noexcept variant with ASan and -fno-exceptions.
206   Multilibs.push_back(Multilib("asan+noexcept", {}, {}, 3)
207                           .flag("+fsanitize=address")
208                           .flag("-fexceptions")
209                           .flag("+fno-exceptions"));
210   Multilibs.FilterOut([&](const Multilib &M) {
211     std::vector<std::string> RD = FilePaths(M);
212     return std::all_of(RD.begin(), RD.end(), [&](std::string P) {
213       return !getVFS().exists(P);
214     });
215   });
216 
217   Multilib::flags_list Flags;
218   addMultilibFlag(
219       Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions, true),
220       "fexceptions", Flags);
221   addMultilibFlag(getSanitizerArgs().needsAsanRt(), "fsanitize=address", Flags);
222   Multilibs.setFilePathsCallback(FilePaths);
223 
224   if (Multilibs.select(Flags, SelectedMultilib))
225     if (!SelectedMultilib.isDefault())
226       if (const auto &PathsCallback = Multilibs.filePathsCallback())
227         for (const auto &Path : PathsCallback(SelectedMultilib))
228           // Prepend the multilib path to ensure it takes the precedence.
229           getFilePaths().insert(getFilePaths().begin(), Path);
230 }
231 
232 std::string Fuchsia::ComputeEffectiveClangTriple(const ArgList &Args,
233                                                  types::ID InputType) const {
234   llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
235   return Triple.str();
236 }
237 
238 Tool *Fuchsia::buildLinker() const {
239   return new tools::fuchsia::Linker(*this);
240 }
241 
242 ToolChain::RuntimeLibType Fuchsia::GetRuntimeLibType(
243     const ArgList &Args) const {
244   if (Arg *A = Args.getLastArg(clang::driver::options::OPT_rtlib_EQ)) {
245     StringRef Value = A->getValue();
246     if (Value != "compiler-rt")
247       getDriver().Diag(clang::diag::err_drv_invalid_rtlib_name)
248           << A->getAsString(Args);
249   }
250 
251   return ToolChain::RLT_CompilerRT;
252 }
253 
254 ToolChain::CXXStdlibType
255 Fuchsia::GetCXXStdlibType(const ArgList &Args) const {
256   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
257     StringRef Value = A->getValue();
258     if (Value != "libc++")
259       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
260         << A->getAsString(Args);
261   }
262 
263   return ToolChain::CST_Libcxx;
264 }
265 
266 void Fuchsia::addClangTargetOptions(const ArgList &DriverArgs,
267                                     ArgStringList &CC1Args,
268                                     Action::OffloadKind) const {
269   if (!DriverArgs.hasFlag(options::OPT_fuse_init_array,
270                           options::OPT_fno_use_init_array, true))
271     CC1Args.push_back("-fno-use-init-array");
272 }
273 
274 void Fuchsia::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
275                                         ArgStringList &CC1Args) const {
276   const Driver &D = getDriver();
277 
278   if (DriverArgs.hasArg(options::OPT_nostdinc))
279     return;
280 
281   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
282     SmallString<128> P(D.ResourceDir);
283     llvm::sys::path::append(P, "include");
284     addSystemInclude(DriverArgs, CC1Args, P);
285   }
286 
287   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
288     return;
289 
290   // Check for configure-time C include directories.
291   StringRef CIncludeDirs(C_INCLUDE_DIRS);
292   if (CIncludeDirs != "") {
293     SmallVector<StringRef, 5> dirs;
294     CIncludeDirs.split(dirs, ":");
295     for (StringRef dir : dirs) {
296       StringRef Prefix =
297           llvm::sys::path::is_absolute(dir) ? "" : StringRef(D.SysRoot);
298       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
299     }
300     return;
301   }
302 
303   if (!D.SysRoot.empty()) {
304     SmallString<128> P(D.SysRoot);
305     llvm::sys::path::append(P, "include");
306     addExternCSystemInclude(DriverArgs, CC1Args, P.str());
307   }
308 }
309 
310 void Fuchsia::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
311                                            ArgStringList &CC1Args) const {
312   if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
313       DriverArgs.hasArg(options::OPT_nostdincxx))
314     return;
315 
316   switch (GetCXXStdlibType(DriverArgs)) {
317   case ToolChain::CST_Libcxx: {
318     SmallString<128> P(getDriver().Dir);
319     llvm::sys::path::append(P, "..", "include", "c++", "v1");
320     addSystemInclude(DriverArgs, CC1Args, P.str());
321     break;
322   }
323 
324   default:
325     llvm_unreachable("invalid stdlib name");
326   }
327 }
328 
329 void Fuchsia::AddCXXStdlibLibArgs(const ArgList &Args,
330                                   ArgStringList &CmdArgs) const {
331   switch (GetCXXStdlibType(Args)) {
332   case ToolChain::CST_Libcxx:
333     CmdArgs.push_back("-lc++");
334     break;
335 
336   case ToolChain::CST_Libstdcxx:
337     llvm_unreachable("invalid stdlib name");
338   }
339 }
340 
341 SanitizerMask Fuchsia::getSupportedSanitizers() const {
342   SanitizerMask Res = ToolChain::getSupportedSanitizers();
343   Res |= SanitizerKind::Address;
344   Res |= SanitizerKind::PointerCompare;
345   Res |= SanitizerKind::PointerSubtract;
346   Res |= SanitizerKind::Fuzzer;
347   Res |= SanitizerKind::FuzzerNoLink;
348   Res |= SanitizerKind::Leak;
349   Res |= SanitizerKind::SafeStack;
350   Res |= SanitizerKind::Scudo;
351   return Res;
352 }
353 
354 SanitizerMask Fuchsia::getDefaultSanitizers() const {
355   SanitizerMask Res;
356   switch (getTriple().getArch()) {
357   case llvm::Triple::aarch64:
358     Res |= SanitizerKind::ShadowCallStack;
359     break;
360   case llvm::Triple::x86_64:
361     Res |= SanitizerKind::SafeStack;
362     break;
363   default:
364     // TODO: Enable SafeStack on RISC-V once tested.
365     break;
366   }
367   return Res;
368 }
369 
370 void Fuchsia::addProfileRTLibs(const llvm::opt::ArgList &Args,
371                                llvm::opt::ArgStringList &CmdArgs) const {
372   // Add linker option -u__llvm_profile_runtime to cause runtime
373   // initialization module to be linked in.
374   if (needsProfileRT(Args))
375     CmdArgs.push_back(Args.MakeArgString(
376         Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
377   ToolChain::addProfileRTLibs(Args, CmdArgs);
378 }
379