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/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 bool wasm::Linker::isLinkJob() const {
27   return true;
28 }
29 
30 bool wasm::Linker::hasIntegratedCPP() const {
31   return false;
32 }
33 
34 void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
35                                 const InputInfo &Output,
36                                 const InputInfoList &Inputs,
37                                 const ArgList &Args,
38                                 const char *LinkingOutput) const {
39 
40   const ToolChain &ToolChain = getToolChain();
41   const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
42   ArgStringList CmdArgs;
43   CmdArgs.push_back("-flavor");
44   CmdArgs.push_back("wasm");
45 
46   if (Args.hasArg(options::OPT_s))
47     CmdArgs.push_back("--strip-all");
48 
49   Args.AddAllArgs(CmdArgs, options::OPT_L);
50   Args.AddAllArgs(CmdArgs, options::OPT_u);
51   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
52 
53   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
54     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
55 
56   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
57 
58   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
59     if (ToolChain.ShouldLinkCXXStdlib(Args))
60       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
61 
62     if (Args.hasArg(options::OPT_pthread))
63       CmdArgs.push_back("-lpthread");
64 
65     CmdArgs.push_back("-allow-undefined-file");
66     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("wasm.syms")));
67     CmdArgs.push_back("-lc");
68     AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
69   }
70 
71   CmdArgs.push_back("-o");
72   CmdArgs.push_back(Output.getFilename());
73 
74   C.addCommand(llvm::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
75 }
76 
77 WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
78                          const llvm::opt::ArgList &Args)
79   : ToolChain(D, Triple, Args) {
80 
81   assert(Triple.isArch32Bit() != Triple.isArch64Bit());
82 
83   getProgramPaths().push_back(getDriver().getInstalledDir());
84 
85   getFilePaths().push_back(getDriver().SysRoot + "/lib");
86 }
87 
88 bool WebAssembly::IsMathErrnoDefault() const { return false; }
89 
90 bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
91 
92 bool WebAssembly::UseObjCMixedDispatch() const { return true; }
93 
94 bool WebAssembly::isPICDefault() const { return false; }
95 
96 bool WebAssembly::isPIEDefault() const { return false; }
97 
98 bool WebAssembly::isPICDefaultForced() const { return false; }
99 
100 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
101 
102 bool WebAssembly::hasBlocksRuntime() const { return false; }
103 
104 // TODO: Support profiling.
105 bool WebAssembly::SupportsProfiling() const { return false; }
106 
107 bool WebAssembly::HasNativeLLVMSupport() const { return true; }
108 
109 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
110                                         ArgStringList &CC1Args,
111                                         Action::OffloadKind) const {
112   if (DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array,
113                          options::OPT_fno_use_init_array, true))
114     CC1Args.push_back("-fuse-init-array");
115 }
116 
117 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
118   return ToolChain::RLT_CompilerRT;
119 }
120 
121 ToolChain::CXXStdlibType WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
122   return ToolChain::CST_Libcxx;
123 }
124 
125 void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
126                                             ArgStringList &CC1Args) const {
127   if (!DriverArgs.hasArg(options::OPT_nostdinc))
128     addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include");
129 }
130 
131 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
132                                                ArgStringList &CC1Args) const {
133   if (!DriverArgs.hasArg(options::OPT_nostdlibinc) &&
134       !DriverArgs.hasArg(options::OPT_nostdincxx))
135     addSystemInclude(DriverArgs, CC1Args,
136                      getDriver().SysRoot + "/include/c++/v1");
137 }
138 
139 std::string WebAssembly::getThreadModel() const {
140   // The WebAssembly MVP does not yet support threads; for now, use the
141   // "single" threading model, which lowers atomics to non-atomic operations.
142   // When threading support is standardized and implemented in popular engines,
143   // this override should be removed.
144   return "single";
145 }
146 
147 Tool *WebAssembly::buildLinker() const {
148   return new tools::wasm::Linker(*this);
149 }
150