[Driver] Update Fuchsia driver path handling

[phosek]

Summary

Several improvements to the Fuchsia driver:

• Search for C++ library headers and libraries in directories that are part of the toolchain distribution rather than sysroot.
• Use LLVM support utlities to construct paths to make sure the driver is also usable on Windows for cross-compiling.
• Change the driver to inherit directly from ToolChain rather than Generic_GCC since we don't need any of the GCC related multilib logic.

[mcgrathr]

Perhaps use llvm::sys::path::parent_path instead of explicit "..".
Perhaps put the getDriver.Dir() + .. + getTriple().str() logic into a shared subroutine.

Use default rather that CST_Libstdcxx in the switches on GetCXXStdlibType.

[phosek]

Done

[mcgrathr]

lgtm

cfe/trunk/lib/Driver/ToolChains/Fuchsia.h

void ConstructJob(Compilation &C, const JobAction &JA,
                     const llvm::opt::ArgList &TCArgs,
                     const char *LinkingOutput) const override;
 };
 } // end namespace fuchsia
 } // end namespace tools
 
 namespace toolchains {
 
-class LLVM_LIBRARY_VISIBILITY Fuchsia : public Generic_ELF {
+class LLVM_LIBRARY_VISIBILITY Fuchsia : public ToolChain {
 public:
   Fuchsia(const Driver &D, const llvm::Triple &Triple,
           const llvm::opt::ArgList &Args);
 
-  bool isPIEDefault() const override { return true; }
   bool HasNativeLLVMSupport() const override { return true; }
   bool IsIntegratedAssemblerDefault() const override { return true; }
+  RuntimeLibType GetDefaultRuntimeLibType() const override {
+    return ToolChain::RLT_CompilerRT;
+  }
+  CXXStdlibType GetDefaultCXXStdlibType() const override {
+    return ToolChain::CST_Libcxx;
+  }
+  bool isPICDefault() const override { return false; }
+  bool isPIEDefault() const override { return true; }
+  bool isPICDefaultForced() const override { return false; }
   llvm::DebuggerKind getDefaultDebuggerTuning() const override {
     return llvm::DebuggerKind::GDB;
   }
 
+  std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
+                                          types::ID InputType) const override;
+
   SanitizerMask getSupportedSanitizers() const override;
 
   RuntimeLibType
   GetRuntimeLibType(const llvm::opt::ArgList &Args) const override;
   CXXStdlibType
   GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
 
   void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
                              llvm::opt::ArgStringList &CC1Args,
                              Action::OffloadKind DeviceOffloadKind) const override;
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
-  std::string findLibCxxIncludePath() const override;
+  void
+  AddClangCXXStdlibIncludeArgs(const llvm::opt::ArgList &DriverArgs,
+                               llvm::opt::ArgStringList &CC1Args) const override;
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
   const char *getDefaultLinker() const override {
     return "lld";
   }
 
 protected:
-  Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_FUCHSIA_H

cfe/trunk/lib/Driver/ToolChains/Fuchsia.cpp

if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
     CmdArgs.push_back("-lc");
   }
 
   C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
 }
 
 /// Fuchsia - Fuchsia tool chain which can call as(1) and ld(1) directly.
 
+static std::string computeTriple(llvm::Triple Triple) {
+  SmallString<64> T;
+  T += Triple.getArchName();
+  T += "-";
+  T += Triple.getOSName();
+  return T.str();
+}
+
+static std::string getTargetDir(const Driver &D,
+                                llvm::Triple Triple) {
+  SmallString<128> P(llvm::sys::path::parent_path(D.Dir));
+  llvm::sys::path::append(P, "lib", computeTriple(Triple));
+  return P.str();
+}
+
 Fuchsia::Fuchsia(const Driver &D, const llvm::Triple &Triple,
                  const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-
-  getFilePaths().push_back(D.SysRoot + "/lib");
-  getFilePaths().push_back(D.ResourceDir + "/lib/fuchsia");
+    : ToolChain(D, Triple, Args) {
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != D.Dir)
+    getProgramPaths().push_back(D.Dir);
+
+  SmallString<128> P(getTargetDir(D, getTriple()));
+  llvm::sys::path::append(P, "lib");
+  getFilePaths().push_back(P.str());
+
+  if (!D.SysRoot.empty()) {
+    SmallString<128> P(D.SysRoot);
+    llvm::sys::path::append(P, "lib");
+    getFilePaths().push_back(P.str());
+  }
 }
 
-Tool *Fuchsia::buildAssembler() const {
-  return new tools::gnutools::Assembler(*this);
+std::string Fuchsia::ComputeEffectiveClangTriple(const ArgList &Args,
+                                                 types::ID InputType) const {
+  llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
+  Triple.setTriple(computeTriple(Triple));
+  return Triple.getTriple();
 }
 
 Tool *Fuchsia::buildLinker() const {
   return new tools::fuchsia::Linker(*this);
 }
 
 ToolChain::RuntimeLibType Fuchsia::GetRuntimeLibType(
     const ArgList &Args) const {
if (CIncludeDirs != "") {
     for (StringRef dir : dirs) {
       StringRef Prefix =
           llvm::sys::path::is_absolute(dir) ? StringRef(D.SysRoot) : "";
       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
     }
     return;
   }
 
-  addExternCSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include");
+  if (!D.SysRoot.empty()) {
+    SmallString<128> P(D.SysRoot);
+    llvm::sys::path::append(P, "include");
+    addExternCSystemInclude(DriverArgs, CC1Args, P.str());
+  }
+}
+
+void Fuchsia::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                           ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
+  switch (GetCXXStdlibType(DriverArgs)) {
+  case ToolChain::CST_Libcxx: {
+    SmallString<128> P(getTargetDir(getDriver(), getTriple()));
+    llvm::sys::path::append(P, "include", "c++", "v1");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+    break;
   }
 
-std::string Fuchsia::findLibCxxIncludePath() const {
-  return getDriver().SysRoot + "/include/c++/v1";
+  default:
+    llvm_unreachable("invalid stdlib name");
+  }
 }
 
 void Fuchsia::AddCXXStdlibLibArgs(const ArgList &Args,
                                   ArgStringList &CmdArgs) const {
-  (void) GetCXXStdlibType(Args);
+  switch (GetCXXStdlibType(Args)) {
+  case ToolChain::CST_Libcxx:
     CmdArgs.push_back("-lc++");
     CmdArgs.push_back("-lc++abi");
     CmdArgs.push_back("-lunwind");
+    break;
+
+  case ToolChain::CST_Libstdcxx:
+    llvm_unreachable("invalid stdlib name");
+  }
 }
 
 SanitizerMask Fuchsia::getSupportedSanitizers() const {
   SanitizerMask Res = ToolChain::getSupportedSanitizers();
   Res |= SanitizerKind::SafeStack;
   return Res;
 }

cfe/trunk/test/Driver/fuchsia.cpp

 // RUN: %clangxx %s -### -no-canonical-prefixes --target=x86_64-unknown-fuchsia \
 // RUN:     --sysroot=%S/platform 2>&1 -fuse-ld=ld | FileCheck %s
 // CHECK: {{.*}}clang{{.*}}" "-cc1"
+// CHECK: "-triple" "x86_64-fuchsia"
 // CHECK: "-fuse-init-array"
 // CHECK: "-isysroot" "[[SYSROOT:[^"]+]]"
-// CHECK: "-internal-isystem" "[[SYSROOT]]{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}v1"
+// CHECK: "-internal-isystem" "{{.*[/\\]}}x86_64-fuchsia{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}v1"
 // CHECK: "-internal-externc-isystem" "[[SYSROOT]]{{/|\\\\}}include"
 // CHECK: {{.*}}lld{{.*}}" "-flavor" "gnu"
 // CHECK: "--sysroot=[[SYSROOT]]"
 // CHECK: "-pie"
 // CHECK: "--build-id"
 // CHECK: "-dynamic-linker" "ld.so.1"
 // CHECK: Scrt1.o
 // CHECK-NOT: crti.o