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(llvm::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 '-target-feature +atomics'
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     CC1Args.push_back("-target-feature");
153     CC1Args.push_back("+atomics");
154   }
155 }
156 
157 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
158   return ToolChain::RLT_CompilerRT;
159 }
160 
161 ToolChain::CXXStdlibType
162 WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
163   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
164     StringRef Value = A->getValue();
165     if (Value != "libc++")
166       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
167           << A->getAsString(Args);
168   }
169   return ToolChain::CST_Libcxx;
170 }
171 
172 void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
173                                             ArgStringList &CC1Args) const {
174   if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
175     return;
176 
177   const Driver &D = getDriver();
178 
179   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
180     SmallString<128> P(D.ResourceDir);
181     llvm::sys::path::append(P, "include");
182     addSystemInclude(DriverArgs, CC1Args, P);
183   }
184 
185   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
186     return;
187 
188   // Check for configure-time C include directories.
189   StringRef CIncludeDirs(C_INCLUDE_DIRS);
190   if (CIncludeDirs != "") {
191     SmallVector<StringRef, 5> dirs;
192     CIncludeDirs.split(dirs, ":");
193     for (StringRef dir : dirs) {
194       StringRef Prefix =
195           llvm::sys::path::is_absolute(dir) ? StringRef(D.SysRoot) : "";
196       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
197     }
198     return;
199   }
200 
201   if (getTriple().getOS() != llvm::Triple::UnknownOS) {
202     const std::string MultiarchTriple =
203         getMultiarchTriple(D, getTriple(), D.SysRoot);
204     addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include/" + MultiarchTriple);
205   }
206   addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include");
207 }
208 
209 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
210                                                ArgStringList &CC1Args) const {
211   if (!DriverArgs.hasArg(options::OPT_nostdlibinc) &&
212       !DriverArgs.hasArg(options::OPT_nostdincxx)) {
213     if (getTriple().getOS() != llvm::Triple::UnknownOS) {
214       const std::string MultiarchTriple =
215           getMultiarchTriple(getDriver(), getTriple(), getDriver().SysRoot);
216       addSystemInclude(DriverArgs, CC1Args,
217                        getDriver().SysRoot + "/include/" + MultiarchTriple +
218                            "/c++/v1");
219     }
220     addSystemInclude(DriverArgs, CC1Args,
221                      getDriver().SysRoot + "/include/c++/v1");
222   }
223 }
224 
225 void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
226                                       llvm::opt::ArgStringList &CmdArgs) const {
227 
228   switch (GetCXXStdlibType(Args)) {
229   case ToolChain::CST_Libcxx:
230     CmdArgs.push_back("-lc++");
231     CmdArgs.push_back("-lc++abi");
232     break;
233   case ToolChain::CST_Libstdcxx:
234     llvm_unreachable("invalid stdlib name");
235   }
236 }
237 
238 SanitizerMask WebAssembly::getSupportedSanitizers() const {
239   SanitizerMask Res = ToolChain::getSupportedSanitizers();
240   if (getTriple().isOSEmscripten()) {
241     Res |= SanitizerKind::Vptr | SanitizerKind::Leak;
242   }
243   return Res;
244 }
245 
246 Tool *WebAssembly::buildLinker() const {
247   return new tools::wasm::Linker(*this);
248 }
249