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/Driver/Compilation.h"
12 #include "clang/Driver/Driver.h"
13 #include "clang/Driver/DriverDiagnostic.h"
14 #include "clang/Driver/Options.h"
15 #include "llvm/Option/ArgList.h"
16 
17 using namespace clang::driver;
18 using namespace clang::driver::tools;
19 using namespace clang::driver::toolchains;
20 using namespace clang;
21 using namespace llvm::opt;
22 
23 wasm::Linker::Linker(const ToolChain &TC)
24     : GnuTool("wasm::Linker", "lld", TC) {}
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 bool wasm::Linker::isLinkJob() const { return true; }
36 
37 bool wasm::Linker::hasIntegratedCPP() const { return false; }
38 
39 void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
40                                 const InputInfo &Output,
41                                 const InputInfoList &Inputs,
42                                 const ArgList &Args,
43                                 const char *LinkingOutput) const {
44 
45   const ToolChain &ToolChain = getToolChain();
46   const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
47   ArgStringList CmdArgs;
48 
49   if (Args.hasArg(options::OPT_s))
50     CmdArgs.push_back("--strip-all");
51 
52   Args.AddAllArgs(CmdArgs, options::OPT_L);
53   Args.AddAllArgs(CmdArgs, options::OPT_u);
54   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
55 
56   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
57     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
58 
59   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
60 
61   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
62     if (ToolChain.ShouldLinkCXXStdlib(Args))
63       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
64 
65     if (Args.hasArg(options::OPT_pthread)) {
66       CmdArgs.push_back("-lpthread");
67       CmdArgs.push_back("--shared-memory");
68     }
69 
70     CmdArgs.push_back("-lc");
71     AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
72   }
73 
74   CmdArgs.push_back("-o");
75   CmdArgs.push_back(Output.getFilename());
76 
77   C.addCommand(llvm::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
78 }
79 
80 WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
81                          const llvm::opt::ArgList &Args)
82     : ToolChain(D, Triple, Args) {
83 
84   assert(Triple.isArch32Bit() != Triple.isArch64Bit());
85 
86   getProgramPaths().push_back(getDriver().getInstalledDir());
87 
88   if (getTriple().getOS() == llvm::Triple::UnknownOS) {
89     // Theoretically an "unknown" OS should mean no standard libraries, however
90     // it could also mean that a custom set of libraries is in use, so just add
91     // /lib to the search path. Disable multiarch in this case, to discourage
92     // paths containing "unknown" from acquiring meanings.
93     getFilePaths().push_back(getDriver().SysRoot + "/lib");
94   } else {
95     const std::string MultiarchTriple =
96         getMultiarchTriple(getDriver(), Triple, getDriver().SysRoot);
97     getFilePaths().push_back(getDriver().SysRoot + "/lib/" + MultiarchTriple);
98   }
99 }
100 
101 bool WebAssembly::IsMathErrnoDefault() const { return false; }
102 
103 bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
104 
105 bool WebAssembly::UseObjCMixedDispatch() const { return true; }
106 
107 bool WebAssembly::isPICDefault() const { return false; }
108 
109 bool WebAssembly::isPIEDefault() const { return false; }
110 
111 bool WebAssembly::isPICDefaultForced() const { return false; }
112 
113 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
114 
115 bool WebAssembly::hasBlocksRuntime() const { return false; }
116 
117 // TODO: Support profiling.
118 bool WebAssembly::SupportsProfiling() const { return false; }
119 
120 bool WebAssembly::HasNativeLLVMSupport() const { return true; }
121 
122 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
123                                         ArgStringList &CC1Args,
124                                         Action::OffloadKind) const {
125   if (DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array,
126                          options::OPT_fno_use_init_array, true))
127     CC1Args.push_back("-fuse-init-array");
128 
129   // '-pthread' implies '-target-feature +atomics'
130   if (DriverArgs.hasFlag(options::OPT_pthread, options::OPT_no_pthread,
131                          false)) {
132     if (DriverArgs.hasFlag(options::OPT_mno_atomics, options::OPT_matomics,
133                            false))
134       getDriver().Diag(diag::err_drv_argument_not_allowed_with)
135           << "-pthread"
136           << "-mno-atomics";
137     CC1Args.push_back("-target-feature");
138     CC1Args.push_back("+atomics");
139   }
140 }
141 
142 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
143   return ToolChain::RLT_CompilerRT;
144 }
145 
146 ToolChain::CXXStdlibType
147 WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
148   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
149     StringRef Value = A->getValue();
150     if (Value != "libc++")
151       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
152           << A->getAsString(Args);
153   }
154   return ToolChain::CST_Libcxx;
155 }
156 
157 void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
158                                             ArgStringList &CC1Args) const {
159   if (!DriverArgs.hasArg(options::OPT_nostdinc)) {
160     if (getTriple().getOS() != llvm::Triple::UnknownOS) {
161       const std::string MultiarchTriple =
162           getMultiarchTriple(getDriver(), getTriple(), getDriver().SysRoot);
163       addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include/" + MultiarchTriple);
164     }
165     addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include");
166   }
167 }
168 
169 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
170                                                ArgStringList &CC1Args) const {
171   if (!DriverArgs.hasArg(options::OPT_nostdlibinc) &&
172       !DriverArgs.hasArg(options::OPT_nostdincxx)) {
173     if (getTriple().getOS() != llvm::Triple::UnknownOS) {
174       const std::string MultiarchTriple =
175           getMultiarchTriple(getDriver(), getTriple(), getDriver().SysRoot);
176       addSystemInclude(DriverArgs, CC1Args,
177                        getDriver().SysRoot + "/include/" + MultiarchTriple + "/c++/v1");
178     }
179     addSystemInclude(DriverArgs, CC1Args,
180                      getDriver().SysRoot + "/include/c++/v1");
181   }
182 }
183 
184 void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
185                                       llvm::opt::ArgStringList &CmdArgs) const {
186 
187   switch (GetCXXStdlibType(Args)) {
188   case ToolChain::CST_Libcxx:
189     CmdArgs.push_back("-lc++");
190     CmdArgs.push_back("-lc++abi");
191     break;
192   case ToolChain::CST_Libstdcxx:
193     llvm_unreachable("invalid stdlib name");
194   }
195 }
196 
197 Tool *WebAssembly::buildLinker() const {
198   return new tools::wasm::Linker(*this);
199 }
200