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 { return true; }
28 
29 bool wasm::Linker::hasIntegratedCPP() const { return false; }
30 
31 void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
32                                 const InputInfo &Output,
33                                 const InputInfoList &Inputs,
34                                 const ArgList &Args,
35                                 const char *LinkingOutput) const {
36 
37   const ToolChain &ToolChain = getToolChain();
38   const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
39   ArgStringList CmdArgs;
40 
41   if (Args.hasArg(options::OPT_s))
42     CmdArgs.push_back("--strip-all");
43 
44   Args.AddAllArgs(CmdArgs, options::OPT_L);
45   Args.AddAllArgs(CmdArgs, options::OPT_u);
46   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
47 
48   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
49     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
50 
51   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
52 
53   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
54     if (ToolChain.ShouldLinkCXXStdlib(Args))
55       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
56 
57     if (Args.hasArg(options::OPT_pthread))
58       CmdArgs.push_back("-lpthread");
59 
60     CmdArgs.push_back("-lc");
61     AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
62   }
63 
64   CmdArgs.push_back("-o");
65   CmdArgs.push_back(Output.getFilename());
66 
67   C.addCommand(llvm::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
68 }
69 
70 WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
71                          const llvm::opt::ArgList &Args)
72     : ToolChain(D, Triple, Args) {
73 
74   assert(Triple.isArch32Bit() != Triple.isArch64Bit());
75 
76   getProgramPaths().push_back(getDriver().getInstalledDir());
77 
78   getFilePaths().push_back(getDriver().SysRoot + "/lib");
79 }
80 
81 bool WebAssembly::IsMathErrnoDefault() const { return false; }
82 
83 bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
84 
85 bool WebAssembly::UseObjCMixedDispatch() const { return true; }
86 
87 bool WebAssembly::isPICDefault() const { return false; }
88 
89 bool WebAssembly::isPIEDefault() const { return false; }
90 
91 bool WebAssembly::isPICDefaultForced() const { return false; }
92 
93 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
94 
95 bool WebAssembly::hasBlocksRuntime() const { return false; }
96 
97 // TODO: Support profiling.
98 bool WebAssembly::SupportsProfiling() const { return false; }
99 
100 bool WebAssembly::HasNativeLLVMSupport() const { return true; }
101 
102 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
103                                         ArgStringList &CC1Args,
104                                         Action::OffloadKind) const {
105   if (DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array,
106                          options::OPT_fno_use_init_array, true))
107     CC1Args.push_back("-fuse-init-array");
108 }
109 
110 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
111   return ToolChain::RLT_CompilerRT;
112 }
113 
114 ToolChain::CXXStdlibType
115 WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
116   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
117     StringRef Value = A->getValue();
118     if (Value != "libc++")
119       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
120           << A->getAsString(Args);
121   }
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 void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
140                                       llvm::opt::ArgStringList &CmdArgs) const {
141 
142   switch (GetCXXStdlibType(Args)) {
143   case ToolChain::CST_Libcxx:
144     CmdArgs.push_back("-lc++");
145     CmdArgs.push_back("-lc++abi");
146     break;
147   case ToolChain::CST_Libstdcxx:
148     llvm_unreachable("invalid stdlib name");
149   }
150 }
151 
152 std::string WebAssembly::getThreadModel() const {
153   // The WebAssembly MVP does not yet support threads; for now, use the
154   // "single" threading model, which lowers atomics to non-atomic operations.
155   // When threading support is standardized and implemented in popular engines,
156   // this override should be removed.
157   return "single";
158 }
159 
160 Tool *WebAssembly::buildLinker() const {
161   return new tools::wasm::Linker(*this);
162 }
163