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_insensitive("ld.lld") ||
58       llvm::sys::path::stem(Exec).equals_insensitive("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("-z");
64     CmdArgs.push_back("rel");
65     CmdArgs.push_back("--pack-dyn-relocs=relr");
66   }
67 
68   if (!D.SysRoot.empty())
69     CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
70 
71   if (!Args.hasArg(options::OPT_shared) && !Args.hasArg(options::OPT_r))
72     CmdArgs.push_back("-pie");
73 
74   if (Args.hasArg(options::OPT_rdynamic))
75     CmdArgs.push_back("-export-dynamic");
76 
77   if (Args.hasArg(options::OPT_s))
78     CmdArgs.push_back("-s");
79 
80   if (Args.hasArg(options::OPT_r)) {
81     CmdArgs.push_back("-r");
82   } else {
83     CmdArgs.push_back("--build-id");
84     CmdArgs.push_back("--hash-style=gnu");
85   }
86 
87   CmdArgs.push_back("--eh-frame-hdr");
88 
89   if (Args.hasArg(options::OPT_static))
90     CmdArgs.push_back("-Bstatic");
91   else if (Args.hasArg(options::OPT_shared))
92     CmdArgs.push_back("-shared");
93 
94   const SanitizerArgs &SanArgs = ToolChain.getSanitizerArgs(Args);
95 
96   if (!Args.hasArg(options::OPT_shared)) {
97     std::string Dyld = D.DyldPrefix;
98     if (SanArgs.needsAsanRt() && SanArgs.needsSharedRt())
99       Dyld += "asan/";
100     if (SanArgs.needsHwasanRt() && SanArgs.needsSharedRt())
101       Dyld += "hwasan/";
102     if (SanArgs.needsTsanRt() && SanArgs.needsSharedRt())
103       Dyld += "tsan/";
104     Dyld += "ld.so.1";
105     CmdArgs.push_back("-dynamic-linker");
106     CmdArgs.push_back(Args.MakeArgString(Dyld));
107   }
108 
109   CmdArgs.push_back("-o");
110   CmdArgs.push_back(Output.getFilename());
111 
112   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,
113                    options::OPT_r)) {
114     if (!Args.hasArg(options::OPT_shared)) {
115       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("Scrt1.o")));
116     }
117   }
118 
119   Args.AddAllArgs(CmdArgs, options::OPT_L);
120   Args.AddAllArgs(CmdArgs, options::OPT_u);
121 
122   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
123 
124   if (D.isUsingLTO()) {
125     assert(!Inputs.empty() && "Must have at least one input.");
126     addLTOOptions(ToolChain, Args, CmdArgs, Output, Inputs[0],
127                   D.getLTOMode() == LTOK_Thin);
128   }
129 
130   addLinkerCompressDebugSectionsOption(ToolChain, Args, CmdArgs);
131   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
132 
133   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
134                    options::OPT_r)) {
135     if (Args.hasArg(options::OPT_static))
136       CmdArgs.push_back("-Bdynamic");
137 
138     if (D.CCCIsCXX()) {
139       if (ToolChain.ShouldLinkCXXStdlib(Args)) {
140         bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
141                                    !Args.hasArg(options::OPT_static);
142         CmdArgs.push_back("--push-state");
143         CmdArgs.push_back("--as-needed");
144         if (OnlyLibstdcxxStatic)
145           CmdArgs.push_back("-Bstatic");
146         ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
147         if (OnlyLibstdcxxStatic)
148           CmdArgs.push_back("-Bdynamic");
149         CmdArgs.push_back("-lm");
150         CmdArgs.push_back("--pop-state");
151       }
152     }
153 
154     // Note that Fuchsia never needs to link in sanitizer runtime deps.  Any
155     // sanitizer runtimes with system dependencies use the `.deplibs` feature
156     // instead.
157     addSanitizerRuntimes(ToolChain, Args, CmdArgs);
158 
159     addXRayRuntime(ToolChain, Args, CmdArgs);
160 
161     ToolChain.addProfileRTLibs(Args, CmdArgs);
162 
163     AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
164 
165     if (Args.hasArg(options::OPT_pthread) ||
166         Args.hasArg(options::OPT_pthreads))
167       CmdArgs.push_back("-lpthread");
168 
169     if (Args.hasArg(options::OPT_fsplit_stack))
170       CmdArgs.push_back("--wrap=pthread_create");
171 
172     if (!Args.hasArg(options::OPT_nolibc))
173       CmdArgs.push_back("-lc");
174   }
175 
176   C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
177                                          Exec, CmdArgs, Inputs, Output));
178 }
179 
180 /// Fuchsia - Fuchsia tool chain which can call as(1) and ld(1) directly.
181 
182 Fuchsia::Fuchsia(const Driver &D, const llvm::Triple &Triple,
183                  const ArgList &Args)
184     : ToolChain(D, Triple, Args) {
185   getProgramPaths().push_back(getDriver().getInstalledDir());
186   if (getDriver().getInstalledDir() != D.Dir)
187     getProgramPaths().push_back(D.Dir);
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     for (const std::string &Path : getStdlibPaths()) {
198       SmallString<128> P(Path);
199       llvm::sys::path::append(P, M.gccSuffix());
200       FP.push_back(std::string(P.str()));
201     }
202     return FP;
203   };
204 
205   Multilibs.push_back(Multilib());
206   // Use the noexcept variant with -fno-exceptions to avoid the extra overhead.
207   Multilibs.push_back(Multilib("noexcept", {}, {}, 1)
208                           .flag("-fexceptions")
209                           .flag("+fno-exceptions"));
210   // ASan has higher priority because we always want the instrumentated version.
211   Multilibs.push_back(Multilib("asan", {}, {}, 2)
212                           .flag("+fsanitize=address"));
213   // Use the asan+noexcept variant with ASan and -fno-exceptions.
214   Multilibs.push_back(Multilib("asan+noexcept", {}, {}, 3)
215                           .flag("+fsanitize=address")
216                           .flag("-fexceptions")
217                           .flag("+fno-exceptions"));
218   // HWASan has higher priority because we always want the instrumentated
219   // version.
220   Multilibs.push_back(
221       Multilib("hwasan", {}, {}, 4).flag("+fsanitize=hwaddress"));
222   // Use the hwasan+noexcept variant with HWASan and -fno-exceptions.
223   Multilibs.push_back(Multilib("hwasan+noexcept", {}, {}, 5)
224                           .flag("+fsanitize=hwaddress")
225                           .flag("-fexceptions")
226                           .flag("+fno-exceptions"));
227   // Use the relative vtables ABI.
228   // TODO: Remove these multilibs once relative vtables are enabled by default
229   // for Fuchsia.
230   Multilibs.push_back(Multilib("relative-vtables", {}, {}, 6)
231                           .flag("+fexperimental-relative-c++-abi-vtables"));
232   Multilibs.push_back(Multilib("relative-vtables+noexcept", {}, {}, 7)
233                           .flag("+fexperimental-relative-c++-abi-vtables")
234                           .flag("-fexceptions")
235                           .flag("+fno-exceptions"));
236   Multilibs.push_back(Multilib("relative-vtables+asan", {}, {}, 8)
237                           .flag("+fexperimental-relative-c++-abi-vtables")
238                           .flag("+fsanitize=address"));
239   Multilibs.push_back(Multilib("relative-vtables+asan+noexcept", {}, {}, 9)
240                           .flag("+fexperimental-relative-c++-abi-vtables")
241                           .flag("+fsanitize=address")
242                           .flag("-fexceptions")
243                           .flag("+fno-exceptions"));
244   Multilibs.push_back(Multilib("relative-vtables+hwasan", {}, {}, 10)
245                           .flag("+fexperimental-relative-c++-abi-vtables")
246                           .flag("+fsanitize=hwaddress"));
247   Multilibs.push_back(Multilib("relative-vtables+hwasan+noexcept", {}, {}, 11)
248                           .flag("+fexperimental-relative-c++-abi-vtables")
249                           .flag("+fsanitize=hwaddress")
250                           .flag("-fexceptions")
251                           .flag("+fno-exceptions"));
252   // Use Itanium C++ ABI for the compat multilib.
253   Multilibs.push_back(Multilib("compat", {}, {}, 12).flag("+fc++-abi=itanium"));
254 
255   Multilibs.FilterOut([&](const Multilib &M) {
256     std::vector<std::string> RD = FilePaths(M);
257     return llvm::all_of(RD, [&](std::string P) { return !getVFS().exists(P); });
258   });
259 
260   Multilib::flags_list Flags;
261   addMultilibFlag(
262       Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions, true),
263       "fexceptions", Flags);
264   addMultilibFlag(getSanitizerArgs(Args).needsAsanRt(), "fsanitize=address",
265                   Flags);
266   addMultilibFlag(getSanitizerArgs(Args).needsHwasanRt(), "fsanitize=hwaddress",
267                   Flags);
268 
269   addMultilibFlag(
270       Args.hasFlag(options::OPT_fexperimental_relative_cxx_abi_vtables,
271                    options::OPT_fno_experimental_relative_cxx_abi_vtables,
272                    /*default=*/false),
273       "fexperimental-relative-c++-abi-vtables", Flags);
274   addMultilibFlag(Args.getLastArgValue(options::OPT_fcxx_abi_EQ) == "itanium",
275                   "fc++-abi=itanium", Flags);
276 
277   Multilibs.setFilePathsCallback(FilePaths);
278 
279   if (Multilibs.select(Flags, SelectedMultilib))
280     if (!SelectedMultilib.isDefault())
281       if (const auto &PathsCallback = Multilibs.filePathsCallback())
282         for (const auto &Path : PathsCallback(SelectedMultilib))
283           // Prepend the multilib path to ensure it takes the precedence.
284           getFilePaths().insert(getFilePaths().begin(), Path);
285 }
286 
287 std::string Fuchsia::ComputeEffectiveClangTriple(const ArgList &Args,
288                                                  types::ID InputType) const {
289   llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
290   return Triple.str();
291 }
292 
293 Tool *Fuchsia::buildLinker() const {
294   return new tools::fuchsia::Linker(*this);
295 }
296 
297 ToolChain::RuntimeLibType Fuchsia::GetRuntimeLibType(
298     const ArgList &Args) const {
299   if (Arg *A = Args.getLastArg(clang::driver::options::OPT_rtlib_EQ)) {
300     StringRef Value = A->getValue();
301     if (Value != "compiler-rt")
302       getDriver().Diag(clang::diag::err_drv_invalid_rtlib_name)
303           << A->getAsString(Args);
304   }
305 
306   return ToolChain::RLT_CompilerRT;
307 }
308 
309 ToolChain::CXXStdlibType
310 Fuchsia::GetCXXStdlibType(const ArgList &Args) const {
311   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
312     StringRef Value = A->getValue();
313     if (Value != "libc++")
314       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
315         << A->getAsString(Args);
316   }
317 
318   return ToolChain::CST_Libcxx;
319 }
320 
321 void Fuchsia::addClangTargetOptions(const ArgList &DriverArgs,
322                                     ArgStringList &CC1Args,
323                                     Action::OffloadKind) const {
324   if (!DriverArgs.hasFlag(options::OPT_fuse_init_array,
325                           options::OPT_fno_use_init_array, true))
326     CC1Args.push_back("-fno-use-init-array");
327 }
328 
329 void Fuchsia::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
330                                         ArgStringList &CC1Args) const {
331   const Driver &D = getDriver();
332 
333   if (DriverArgs.hasArg(options::OPT_nostdinc))
334     return;
335 
336   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
337     SmallString<128> P(D.ResourceDir);
338     llvm::sys::path::append(P, "include");
339     addSystemInclude(DriverArgs, CC1Args, P);
340   }
341 
342   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
343     return;
344 
345   // Check for configure-time C include directories.
346   StringRef CIncludeDirs(C_INCLUDE_DIRS);
347   if (CIncludeDirs != "") {
348     SmallVector<StringRef, 5> dirs;
349     CIncludeDirs.split(dirs, ":");
350     for (StringRef dir : dirs) {
351       StringRef Prefix =
352           llvm::sys::path::is_absolute(dir) ? "" : StringRef(D.SysRoot);
353       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
354     }
355     return;
356   }
357 
358   if (!D.SysRoot.empty()) {
359     SmallString<128> P(D.SysRoot);
360     llvm::sys::path::append(P, "include");
361     addExternCSystemInclude(DriverArgs, CC1Args, P.str());
362   }
363 }
364 
365 void Fuchsia::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
366                                            ArgStringList &CC1Args) const {
367   if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
368       DriverArgs.hasArg(options::OPT_nostdincxx))
369     return;
370 
371   const Driver &D = getDriver();
372   std::string Target = getTripleString();
373 
374   auto AddCXXIncludePath = [&](StringRef Path) {
375     std::string Version = detectLibcxxVersion(Path);
376     if (Version.empty())
377       return;
378 
379     // First add the per-target include path.
380     SmallString<128> TargetDir(Path);
381     llvm::sys::path::append(TargetDir, Target, "c++", Version);
382     if (getVFS().exists(TargetDir))
383       addSystemInclude(DriverArgs, CC1Args, TargetDir);
384 
385     // Second add the generic one.
386     SmallString<128> Dir(Path);
387     llvm::sys::path::append(Dir, "c++", Version);
388     addSystemInclude(DriverArgs, CC1Args, Dir);
389   };
390 
391   switch (GetCXXStdlibType(DriverArgs)) {
392   case ToolChain::CST_Libcxx: {
393     SmallString<128> P(D.Dir);
394     llvm::sys::path::append(P, "..", "include");
395     AddCXXIncludePath(P);
396     break;
397   }
398 
399   default:
400     llvm_unreachable("invalid stdlib name");
401   }
402 }
403 
404 void Fuchsia::AddCXXStdlibLibArgs(const ArgList &Args,
405                                   ArgStringList &CmdArgs) const {
406   switch (GetCXXStdlibType(Args)) {
407   case ToolChain::CST_Libcxx:
408     CmdArgs.push_back("-lc++");
409     break;
410 
411   case ToolChain::CST_Libstdcxx:
412     llvm_unreachable("invalid stdlib name");
413   }
414 }
415 
416 SanitizerMask Fuchsia::getSupportedSanitizers() const {
417   SanitizerMask Res = ToolChain::getSupportedSanitizers();
418   Res |= SanitizerKind::Address;
419   Res |= SanitizerKind::HWAddress;
420   Res |= SanitizerKind::PointerCompare;
421   Res |= SanitizerKind::PointerSubtract;
422   Res |= SanitizerKind::Fuzzer;
423   Res |= SanitizerKind::FuzzerNoLink;
424   Res |= SanitizerKind::Leak;
425   Res |= SanitizerKind::SafeStack;
426   Res |= SanitizerKind::Scudo;
427   Res |= SanitizerKind::Thread;
428   return Res;
429 }
430 
431 SanitizerMask Fuchsia::getDefaultSanitizers() const {
432   SanitizerMask Res;
433   switch (getTriple().getArch()) {
434   case llvm::Triple::aarch64:
435     Res |= SanitizerKind::ShadowCallStack;
436     break;
437   case llvm::Triple::x86_64:
438     Res |= SanitizerKind::SafeStack;
439     break;
440   default:
441     // TODO: Enable SafeStack on RISC-V once tested.
442     break;
443   }
444   return Res;
445 }
446