[Driver][BareMetal] Support --emit-static-lib in BareMetal driver

[phosek]

Summary

This allows building static libraries with Clang driver.

[abrachet]

clang/lib/Driver/ToolChains/BareMetal.cpp

227

Looks like clang-format is complaining about this file

[phosek]

clang/lib/Driver/ToolChains/BareMetal.cpp

227

Addressed in the commit.

clang/lib/Driver/ToolChains/BareMetal.h

public:
 
   static bool handlesTarget(const llvm::Triple &Triple);
 
   void findMultilibs(const Driver &D, const llvm::Triple &Triple,
                      const llvm::opt::ArgList &Args);
 
 protected:
   Tool *buildLinker() const override;
+  Tool *buildStaticLibTool() const override;
 
 public:
   bool useIntegratedAs() const override { return true; }
   bool isBareMetal() const override { return true; }
   bool isCrossCompiling() const override { return true; }
   bool HasNativeLLVMSupport() const override { return true; }
   bool isPICDefault() const override { return false; }
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override {
private:
   OrderedMultilibs getOrderedMultilibs() const;
 };
 
 } // namespace toolchains
 
 namespace tools {
 namespace baremetal {
 
+class LLVM_LIBRARY_VISIBILITY StaticLibTool : public Tool {
+public:
+  StaticLibTool(const ToolChain &TC)
+      : Tool("baremetal::StaticLibTool", "llvm-ar", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+  bool isLinkJob() const override { return true; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+
 class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
 public:
   Linker(const ToolChain &TC) : Tool("baremetal::Linker", "ld.lld", TC) {}
   bool isLinkJob() const override { return true; }
   bool hasIntegratedCPP() const override { return false; }
   void ConstructJob(Compilation &C, const JobAction &JA,
                     const InputInfo &Output, const InputInfoList &Inputs,
                     const llvm::opt::ArgList &TCArgs,

clang/lib/Driver/ToolChains/BareMetal.cpp

if (isRISCVBareMetal(Triple)) {
     llvm::sys::path::append(MultilibPath, MultilibFilename);
     findMultilibsFromYAML(*this, D, MultilibPath, Args, Result);
     SelectedMultilibs = Result.SelectedMultilibs;
     Multilibs = Result.Multilibs;
   }
 }
 
 bool BareMetal::handlesTarget(const llvm::Triple &Triple) {
   return isARMBareMetal(Triple) || isAArch64BareMetal(Triple) ||
          isRISCVBareMetal(Triple);
 }
 
 Tool *BareMetal::buildLinker() const {
   return new tools::baremetal::Linker(*this);
 }
 
+Tool *BareMetal::buildStaticLibTool() const {
+  return new tools::baremetal::StaticLibTool(*this);
+}
+
 std::string BareMetal::computeSysRoot() const {
   return computeBaseSysRoot(getDriver(), getTriple());
 }
 
 BareMetal::OrderedMultilibs BareMetal::getOrderedMultilibs() const {
   // Get multilibs in reverse order because they're ordered most-specific last.
   if (!SelectedMultilibs.empty())
     return llvm::reverse(SelectedMultilibs);
void BareMetal::AddLinkRuntimeLib(const ArgList &Args,
   }
   case ToolChain::RLT_Libgcc:
     CmdArgs.push_back("-lgcc");
     return;
   }
   llvm_unreachable("Unhandled RuntimeLibType.");
 }
 
+void baremetal::StaticLibTool::ConstructJob(Compilation &C, const JobAction &JA,
+                                            const InputInfo &Output,
+                                            const InputInfoList &Inputs,
+                                            const ArgList &Args,
+                                            const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+
+  // Silence warning for "clang -g foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_g_Group);
+  // and "clang -emit-llvm foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+  // and for "clang -w foo.o -o foo". Other warning options are already
+  // handled somewhere else.
+  Args.ClaimAllArgs(options::OPT_w);
+  // Silence warnings when linking C code with a C++ '-stdlib' argument.
+  Args.ClaimAllArgs(options::OPT_stdlib_EQ);
+
+  // ar tool command "llvm-ar <options> <output_file> <input_files>".
+  ArgStringList CmdArgs;
+  // Create and insert file members with a deterministic index.
+  CmdArgs.push_back("rcsD");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (const auto &II : Inputs) {
+    if (II.isFilename()) {
+      CmdArgs.push_back(II.getFilename());
+    }
+  }
+
+  // Delete old output archive file if it already exists before generating a new
+  // archive file.
+  const char *OutputFileName = Output.getFilename();
+  if (Output.isFilename() && llvm::sys::fs::exists(OutputFileName)) {
+    if (std::error_code EC = llvm::sys::fs::remove(OutputFileName)) {
+      D.Diag(diag::err_drv_unable_to_remove_file) << EC.message();
+      return;
+    }
+  }
+
+  const char *Exec = Args.MakeArgString(getToolChain().GetStaticLibToolPath());
+  C.addCommand(std::make_unique<Command>(JA, *this,
+                                         ResponseFileSupport::AtFileCurCP(),
+                                         Exec, CmdArgs, Inputs, Output));
+}
+
 void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                      const InputInfo &Output,
                                      const InputInfoList &Inputs,
                                      const ArgList &Args,
                                      const char *LinkingOutput) const {
   ArgStringList CmdArgs;
 
   auto &TC = static_cast<const toolchains::BareMetal &>(getToolChain());
void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // and arm*-*-eabi (the default is R_ARM_GOT_PREL, used on arm*-*-linux and
   // arm*-*-*bsd).
   if (isARMBareMetal(TC.getTriple()))
     CmdArgs.push_back("--target2=rel");
 
   CmdArgs.push_back("-o");
   CmdArgs.push_back(Output.getFilename());
 
-  C.addCommand(std::make_unique<Command>(JA, *this,
-                                         ResponseFileSupport::AtFileCurCP(),
-                                         Args.MakeArgString(TC.GetLinkerPath()),
-                                         CmdArgs, Inputs, Output));
+  C.addCommand(std::make_unique<Command>(
+      JA, *this, ResponseFileSupport::AtFileCurCP(),
+      Args.MakeArgString(TC.GetLinkerPath()), CmdArgs, Inputs, Output));
 }

clang/test/Driver/baremetal.cpp

 // UNSUPPORTED: system-windows
 
+// RUN: %clang -### %s --target=armv6-none-eabi --emit-static-lib 2>&1 \
+// RUN:   | FileCheck -check-prefixes=CHECK-STATIC-LIB %s
+// CHECK-STATIC-LIB: {{.*}}llvm-ar{{.*}}" "rcsD"
+
 // RUN: %clang %s -### --target=armv6m-none-eabi -o %t.out 2>&1 \
 // RUN:     -T semihosted.lds \
 // RUN:     -L some/directory/user/asked/for \
 // RUN:     --sysroot=%S/Inputs/baremetal_arm \
 // RUN:   | FileCheck --check-prefix=CHECK-V6M-C %s
 // CHECK-V6M-C:      "-cc1" "-triple" "thumbv6m-none-unknown-eabi"
 // CHECK-V6M-C-SAME: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
 // CHECK-V6M-C-SAME: "-isysroot" "[[SYSROOT:[^"]*]]"