1 //===--- WebAssembly.cpp - WebAssembly ToolChain Implementation -*- 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 "WebAssembly.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 "llvm/Support/FileSystem.h"
17 #include "llvm/Support/Path.h"
18 #include "llvm/Option/ArgList.h"
19 
20 using namespace clang::driver;
21 using namespace clang::driver::tools;
22 using namespace clang::driver::toolchains;
23 using namespace clang;
24 using namespace llvm::opt;
25 
26 /// Following the conventions in https://wiki.debian.org/Multiarch/Tuples,
27 /// we remove the vendor field to form the multiarch triple.
28 static std::string getMultiarchTriple(const Driver &D,
29                                       const llvm::Triple &TargetTriple,
30                                       StringRef SysRoot) {
31     return (TargetTriple.getArchName() + "-" +
32             TargetTriple.getOSAndEnvironmentName()).str();
33 }
34 
35 std::string wasm::Linker::getLinkerPath(const ArgList &Args) const {
36   const ToolChain &ToolChain = getToolChain();
37   if (const Arg* A = Args.getLastArg(options::OPT_fuse_ld_EQ)) {
38     StringRef UseLinker = A->getValue();
39     if (!UseLinker.empty()) {
40       if (llvm::sys::path::is_absolute(UseLinker) &&
41           llvm::sys::fs::can_execute(UseLinker))
42         return UseLinker;
43 
44       // Accept 'lld', and 'ld' as aliases for the default linker
45       if (UseLinker != "lld" && UseLinker != "ld")
46         ToolChain.getDriver().Diag(diag::err_drv_invalid_linker_name)
47             << A->getAsString(Args);
48     }
49   }
50 
51   return ToolChain.GetProgramPath(ToolChain.getDefaultLinker());
52 }
53 
54 void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
55                                 const InputInfo &Output,
56                                 const InputInfoList &Inputs,
57                                 const ArgList &Args,
58                                 const char *LinkingOutput) const {
59 
60   const ToolChain &ToolChain = getToolChain();
61   const char *Linker = Args.MakeArgString(getLinkerPath(Args));
62   ArgStringList CmdArgs;
63 
64   if (Args.hasArg(options::OPT_s))
65     CmdArgs.push_back("--strip-all");
66 
67   Args.AddAllArgs(CmdArgs, options::OPT_L);
68   Args.AddAllArgs(CmdArgs, options::OPT_u);
69   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
70 
71   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
72     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
73 
74   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
75 
76   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
77     if (ToolChain.ShouldLinkCXXStdlib(Args))
78       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
79 
80     if (Args.hasArg(options::OPT_pthread)) {
81       CmdArgs.push_back("-lpthread");
82       CmdArgs.push_back("--shared-memory");
83     }
84 
85     CmdArgs.push_back("-lc");
86     AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
87   }
88 
89   CmdArgs.push_back("-o");
90   CmdArgs.push_back(Output.getFilename());
91 
92   C.addCommand(std::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
93 }
94 
95 WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
96                          const llvm::opt::ArgList &Args)
97     : ToolChain(D, Triple, Args) {
98 
99   assert(Triple.isArch32Bit() != Triple.isArch64Bit());
100 
101   getProgramPaths().push_back(getDriver().getInstalledDir());
102 
103   if (getTriple().getOS() == llvm::Triple::UnknownOS) {
104     // Theoretically an "unknown" OS should mean no standard libraries, however
105     // it could also mean that a custom set of libraries is in use, so just add
106     // /lib to the search path. Disable multiarch in this case, to discourage
107     // paths containing "unknown" from acquiring meanings.
108     getFilePaths().push_back(getDriver().SysRoot + "/lib");
109   } else {
110     const std::string MultiarchTriple =
111         getMultiarchTriple(getDriver(), Triple, getDriver().SysRoot);
112     getFilePaths().push_back(getDriver().SysRoot + "/lib/" + MultiarchTriple);
113   }
114 }
115 
116 bool WebAssembly::IsMathErrnoDefault() const { return false; }
117 
118 bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
119 
120 bool WebAssembly::UseObjCMixedDispatch() const { return true; }
121 
122 bool WebAssembly::isPICDefault() const { return false; }
123 
124 bool WebAssembly::isPIEDefault() const { return false; }
125 
126 bool WebAssembly::isPICDefaultForced() const { return false; }
127 
128 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
129 
130 bool WebAssembly::hasBlocksRuntime() const { return false; }
131 
132 // TODO: Support profiling.
133 bool WebAssembly::SupportsProfiling() const { return false; }
134 
135 bool WebAssembly::HasNativeLLVMSupport() const { return true; }
136 
137 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
138                                         ArgStringList &CC1Args,
139                                         Action::OffloadKind) const {
140   if (DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array,
141                          options::OPT_fno_use_init_array, true))
142     CC1Args.push_back("-fuse-init-array");
143 
144   // '-pthread' implies atomics, bulk-memory, mutable-globals, and sign-ext
145   if (DriverArgs.hasFlag(options::OPT_pthread, options::OPT_no_pthread,
146                          false)) {
147     if (DriverArgs.hasFlag(options::OPT_mno_atomics, options::OPT_matomics,
148                            false))
149       getDriver().Diag(diag::err_drv_argument_not_allowed_with)
150           << "-pthread"
151           << "-mno-atomics";
152     if (DriverArgs.hasFlag(options::OPT_mno_bulk_memory,
153                            options::OPT_mbulk_memory, false))
154       getDriver().Diag(diag::err_drv_argument_not_allowed_with)
155           << "-pthread"
156           << "-mno-bulk-memory";
157     if (DriverArgs.hasFlag(options::OPT_mno_mutable_globals,
158                            options::OPT_mmutable_globals, false))
159       getDriver().Diag(diag::err_drv_argument_not_allowed_with)
160           << "-pthread"
161           << "-mno-mutable-globals";
162     if (DriverArgs.hasFlag(options::OPT_mno_sign_ext, options::OPT_msign_ext,
163                            false))
164       getDriver().Diag(diag::err_drv_argument_not_allowed_with)
165           << "-pthread"
166           << "-mno-sign-ext";
167     CC1Args.push_back("-target-feature");
168     CC1Args.push_back("+atomics");
169     CC1Args.push_back("-target-feature");
170     CC1Args.push_back("+bulk-memory");
171     CC1Args.push_back("-target-feature");
172     CC1Args.push_back("+mutable-globals");
173     CC1Args.push_back("-target-feature");
174     CC1Args.push_back("+sign-ext");
175   }
176 
177   if (DriverArgs.getLastArg(options::OPT_fwasm_exceptions)) {
178     // '-fwasm-exceptions' is not compatible with '-mno-exception-handling'
179     if (DriverArgs.hasFlag(options::OPT_mno_exception_handing,
180                            options::OPT_mexception_handing, false))
181       getDriver().Diag(diag::err_drv_argument_not_allowed_with)
182           << "-fwasm-exceptions"
183           << "-mno-exception-handling";
184     // '-fwasm-exceptions' is not compatible with '-mno-reference-types'
185     if (DriverArgs.hasFlag(options::OPT_mno_reference_types,
186                            options::OPT_mexception_handing, false))
187       getDriver().Diag(diag::err_drv_argument_not_allowed_with)
188           << "-fwasm-exceptions"
189           << "-mno-reference-types";
190     // '-fwasm-exceptions' is not compatible with
191     // '-mllvm -enable-emscripten-cxx-exceptions'
192     for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) {
193       if (StringRef(A->getValue(0)) == "-enable-emscripten-cxx-exceptions")
194         getDriver().Diag(diag::err_drv_argument_not_allowed_with)
195             << "-fwasm-exceptions"
196             << "-mllvm -enable-emscripten-cxx-exceptions";
197     }
198     // '-fwasm-exceptions' implies exception-handling and reference-types
199     CC1Args.push_back("-target-feature");
200     CC1Args.push_back("+exception-handling");
201     CC1Args.push_back("-target-feature");
202     CC1Args.push_back("+reference-types");
203   }
204 }
205 
206 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
207   return ToolChain::RLT_CompilerRT;
208 }
209 
210 ToolChain::CXXStdlibType
211 WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
212   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
213     StringRef Value = A->getValue();
214     if (Value != "libc++")
215       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
216           << A->getAsString(Args);
217   }
218   return ToolChain::CST_Libcxx;
219 }
220 
221 void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
222                                             ArgStringList &CC1Args) const {
223   if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
224     return;
225 
226   const Driver &D = getDriver();
227 
228   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
229     SmallString<128> P(D.ResourceDir);
230     llvm::sys::path::append(P, "include");
231     addSystemInclude(DriverArgs, CC1Args, P);
232   }
233 
234   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
235     return;
236 
237   // Check for configure-time C include directories.
238   StringRef CIncludeDirs(C_INCLUDE_DIRS);
239   if (CIncludeDirs != "") {
240     SmallVector<StringRef, 5> dirs;
241     CIncludeDirs.split(dirs, ":");
242     for (StringRef dir : dirs) {
243       StringRef Prefix =
244           llvm::sys::path::is_absolute(dir) ? StringRef(D.SysRoot) : "";
245       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
246     }
247     return;
248   }
249 
250   if (getTriple().getOS() != llvm::Triple::UnknownOS) {
251     const std::string MultiarchTriple =
252         getMultiarchTriple(D, getTriple(), D.SysRoot);
253     addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include/" + MultiarchTriple);
254   }
255   addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include");
256 }
257 
258 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
259                                                ArgStringList &CC1Args) const {
260   if (!DriverArgs.hasArg(options::OPT_nostdlibinc) &&
261       !DriverArgs.hasArg(options::OPT_nostdincxx)) {
262     if (getTriple().getOS() != llvm::Triple::UnknownOS) {
263       const std::string MultiarchTriple =
264           getMultiarchTriple(getDriver(), getTriple(), getDriver().SysRoot);
265       addSystemInclude(DriverArgs, CC1Args,
266                        getDriver().SysRoot + "/include/" + MultiarchTriple +
267                            "/c++/v1");
268     }
269     addSystemInclude(DriverArgs, CC1Args,
270                      getDriver().SysRoot + "/include/c++/v1");
271   }
272 }
273 
274 void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
275                                       llvm::opt::ArgStringList &CmdArgs) const {
276 
277   switch (GetCXXStdlibType(Args)) {
278   case ToolChain::CST_Libcxx:
279     CmdArgs.push_back("-lc++");
280     CmdArgs.push_back("-lc++abi");
281     break;
282   case ToolChain::CST_Libstdcxx:
283     llvm_unreachable("invalid stdlib name");
284   }
285 }
286 
287 SanitizerMask WebAssembly::getSupportedSanitizers() const {
288   SanitizerMask Res = ToolChain::getSupportedSanitizers();
289   if (getTriple().isOSEmscripten()) {
290     Res |= SanitizerKind::Vptr | SanitizerKind::Leak | SanitizerKind::Address;
291   }
292   return Res;
293 }
294 
295 Tool *WebAssembly::buildLinker() const {
296   return new tools::wasm::Linker(*this);
297 }
298