1 //===--- WebAssembly.cpp - WebAssembly ToolChain Implementation -*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "WebAssembly.h"
11 #include "CommonArgs.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/Option/ArgList.h"
17 
18 using namespace clang::driver;
19 using namespace clang::driver::tools;
20 using namespace clang::driver::toolchains;
21 using namespace clang;
22 using namespace llvm::opt;
23 
24 wasm::Linker::Linker(const ToolChain &TC)
25   : GnuTool("wasm::Linker", "lld", TC) {}
26 
27 bool wasm::Linker::isLinkJob() const {
28   return true;
29 }
30 
31 bool wasm::Linker::hasIntegratedCPP() const {
32   return false;
33 }
34 
35 void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
36                                 const InputInfo &Output,
37                                 const InputInfoList &Inputs,
38                                 const ArgList &Args,
39                                 const char *LinkingOutput) const {
40 
41   const ToolChain &ToolChain = getToolChain();
42   const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
43   ArgStringList CmdArgs;
44   CmdArgs.push_back("-flavor");
45   CmdArgs.push_back("wasm");
46 
47   if (Args.hasArg(options::OPT_s))
48     CmdArgs.push_back("--strip-all");
49 
50   Args.AddAllArgs(CmdArgs, options::OPT_L);
51   Args.AddAllArgs(CmdArgs, options::OPT_u);
52   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
53 
54   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
55     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
56 
57   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
58 
59   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
60     if (ToolChain.ShouldLinkCXXStdlib(Args))
61       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
62 
63     if (Args.hasArg(options::OPT_pthread))
64       CmdArgs.push_back("-lpthread");
65 
66     CmdArgs.push_back("-lc");
67     AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
68   }
69 
70   CmdArgs.push_back("-o");
71   CmdArgs.push_back(Output.getFilename());
72 
73   C.addCommand(llvm::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
74 }
75 
76 WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
77                          const llvm::opt::ArgList &Args)
78   : ToolChain(D, Triple, Args) {
79 
80   assert(Triple.isArch32Bit() != Triple.isArch64Bit());
81 
82   getProgramPaths().push_back(getDriver().getInstalledDir());
83 
84   getFilePaths().push_back(getDriver().SysRoot + "/lib");
85 }
86 
87 bool WebAssembly::IsMathErrnoDefault() const { return false; }
88 
89 bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
90 
91 bool WebAssembly::UseObjCMixedDispatch() const { return true; }
92 
93 bool WebAssembly::isPICDefault() const { return false; }
94 
95 bool WebAssembly::isPIEDefault() const { return false; }
96 
97 bool WebAssembly::isPICDefaultForced() const { return false; }
98 
99 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
100 
101 bool WebAssembly::hasBlocksRuntime() const { return false; }
102 
103 // TODO: Support profiling.
104 bool WebAssembly::SupportsProfiling() const { return false; }
105 
106 bool WebAssembly::HasNativeLLVMSupport() const { return true; }
107 
108 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
109                                         ArgStringList &CC1Args,
110                                         Action::OffloadKind) const {
111   if (DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array,
112                          options::OPT_fno_use_init_array, true))
113     CC1Args.push_back("-fuse-init-array");
114 }
115 
116 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
117   return ToolChain::RLT_CompilerRT;
118 }
119 
120 ToolChain::CXXStdlibType WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
121   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
122     StringRef Value = A->getValue();
123     if (Value != "libc++")
124       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
125           << A->getAsString(Args);
126   }
127   return ToolChain::CST_Libcxx;
128 }
129 
130 void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
131                                             ArgStringList &CC1Args) const {
132   if (!DriverArgs.hasArg(options::OPT_nostdinc))
133     addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include");
134 }
135 
136 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
137                                                ArgStringList &CC1Args) const {
138   if (!DriverArgs.hasArg(options::OPT_nostdlibinc) &&
139       !DriverArgs.hasArg(options::OPT_nostdincxx))
140     addSystemInclude(DriverArgs, CC1Args,
141                      getDriver().SysRoot + "/include/c++/v1");
142 }
143 
144 void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
145                                       llvm::opt::ArgStringList &CmdArgs) const {
146 
147   switch (GetCXXStdlibType(Args)) {
148   case ToolChain::CST_Libcxx:
149     CmdArgs.push_back("-lc++");
150     CmdArgs.push_back("-lc++abi");
151     break;
152   case ToolChain::CST_Libstdcxx:
153     llvm_unreachable("invalid stdlib name");
154   }
155 }
156 
157 std::string WebAssembly::getThreadModel() const {
158   // The WebAssembly MVP does not yet support threads; for now, use the
159   // "single" threading model, which lowers atomics to non-atomic operations.
160   // When threading support is standardized and implemented in popular engines,
161   // this override should be removed.
162   return "single";
163 }
164 
165 Tool *WebAssembly::buildLinker() const {
166   return new tools::wasm::Linker(*this);
167 }
168