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 
45   if (Args.hasArg(options::OPT_s))
46     CmdArgs.push_back("--strip-all");
47 
48   Args.AddAllArgs(CmdArgs, options::OPT_L);
49   Args.AddAllArgs(CmdArgs, options::OPT_u);
50   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
51 
52   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
53     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
54 
55   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
56 
57   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
58     if (ToolChain.ShouldLinkCXXStdlib(Args))
59       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
60 
61     if (Args.hasArg(options::OPT_pthread))
62       CmdArgs.push_back("-lpthread");
63 
64     CmdArgs.push_back("-lc");
65     AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
66   }
67 
68   CmdArgs.push_back("-o");
69   CmdArgs.push_back(Output.getFilename());
70 
71   C.addCommand(llvm::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
72 }
73 
74 WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
75                          const llvm::opt::ArgList &Args)
76   : ToolChain(D, Triple, Args) {
77 
78   assert(Triple.isArch32Bit() != Triple.isArch64Bit());
79 
80   getProgramPaths().push_back(getDriver().getInstalledDir());
81 
82   getFilePaths().push_back(getDriver().SysRoot + "/lib");
83 }
84 
85 bool WebAssembly::IsMathErrnoDefault() const { return false; }
86 
87 bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
88 
89 bool WebAssembly::UseObjCMixedDispatch() const { return true; }
90 
91 bool WebAssembly::isPICDefault() const { return false; }
92 
93 bool WebAssembly::isPIEDefault() const { return false; }
94 
95 bool WebAssembly::isPICDefaultForced() const { return false; }
96 
97 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
98 
99 bool WebAssembly::hasBlocksRuntime() const { return false; }
100 
101 // TODO: Support profiling.
102 bool WebAssembly::SupportsProfiling() const { return false; }
103 
104 bool WebAssembly::HasNativeLLVMSupport() const { return true; }
105 
106 void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
107                                         ArgStringList &CC1Args,
108                                         Action::OffloadKind) const {
109   if (DriverArgs.hasFlag(clang::driver::options::OPT_fuse_init_array,
110                          options::OPT_fno_use_init_array, true))
111     CC1Args.push_back("-fuse-init-array");
112 }
113 
114 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
115   return ToolChain::RLT_CompilerRT;
116 }
117 
118 ToolChain::CXXStdlibType WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
119   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
120     StringRef Value = A->getValue();
121     if (Value != "libc++")
122       getDriver().Diag(diag::err_drv_invalid_stdlib_name)
123           << A->getAsString(Args);
124   }
125   return ToolChain::CST_Libcxx;
126 }
127 
128 void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
129                                             ArgStringList &CC1Args) const {
130   if (!DriverArgs.hasArg(options::OPT_nostdinc))
131     addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include");
132 }
133 
134 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
135                                                ArgStringList &CC1Args) const {
136   if (!DriverArgs.hasArg(options::OPT_nostdlibinc) &&
137       !DriverArgs.hasArg(options::OPT_nostdincxx))
138     addSystemInclude(DriverArgs, CC1Args,
139                      getDriver().SysRoot + "/include/c++/v1");
140 }
141 
142 void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
143                                       llvm::opt::ArgStringList &CmdArgs) const {
144 
145   switch (GetCXXStdlibType(Args)) {
146   case ToolChain::CST_Libcxx:
147     CmdArgs.push_back("-lc++");
148     CmdArgs.push_back("-lc++abi");
149     break;
150   case ToolChain::CST_Libstdcxx:
151     llvm_unreachable("invalid stdlib name");
152   }
153 }
154 
155 std::string WebAssembly::getThreadModel() const {
156   // The WebAssembly MVP does not yet support threads; for now, use the
157   // "single" threading model, which lowers atomics to non-atomic operations.
158   // When threading support is standardized and implemented in popular engines,
159   // this override should be removed.
160   return "single";
161 }
162 
163 Tool *WebAssembly::buildLinker() const {
164   return new tools::wasm::Linker(*this);
165 }
166