[MSP430] Actualize the toolchain description

Reviewed By: krisb

Differential Revision: https://reviews.llvm.org/D81676

clang/include/clang/Driver/Options.td

@@ -2193,6 +2193,7 @@ def municode : Joined<["-"], "municode">, Group<m_Group>, Flags<[DriverOption]>;
 def mthreads : Joined<["-"], "mthreads">, Group<m_Group>, Flags<[DriverOption]>;
 def mcpu_EQ : Joined<["-"], "mcpu=">, Group<m_Group>;
 def mmcu_EQ : Joined<["-"], "mmcu=">, Group<m_Group>;
+def msim : Flag<["-"], "msim">, Group<m_Group>;
 def mdynamic_no_pic : Joined<["-"], "mdynamic-no-pic">, Group<m_Group>;
 def mfix_and_continue : Flag<["-"], "mfix-and-continue">, Group<clang_ignored_m_Group>;
 def mieee_fp : Flag<["-"], "mieee-fp">, Group<clang_ignored_m_Group>;
@@ -2278,9 +2279,9 @@ def m_seses : Flag<["-"], "mseses">, Group<m_Group>, Flags<[CoreOption, DriverOp
 def mno_seses : Flag<["-"], "mno-seses">, Group<m_Group>, Flags<[CoreOption, DriverOption]>,
   HelpText<"Disable speculative execution side effect suppression (SESES)">;
 
-def mrelax : Flag<["-"], "mrelax">, Group<m_riscv_Features_Group>,
+def mrelax : Flag<["-"], "mrelax">, Group<m_Group>,
   HelpText<"Enable linker relaxation">;
-def mno_relax : Flag<["-"], "mno-relax">, Group<m_riscv_Features_Group>,
+def mno_relax : Flag<["-"], "mno-relax">, Group<m_Group>,
   HelpText<"Disable linker relaxation">;
 def msmall_data_limit_EQ : Joined<["-"], "msmall-data-limit=">, Group<m_Group>,
   Alias<G>,

clang/lib/Basic/Targets/MSP430.cpp

@@ -29,5 +29,6 @@ void MSP430TargetInfo::getTargetDefines(const LangOptions &Opts,
                                         MacroBuilder &Builder) const {
   Builder.defineMacro("MSP430");
   Builder.defineMacro("__MSP430__");
+  Builder.defineMacro("__ELF__");
   // FIXME: defines for different 'flavours' of MCU
 }

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -1552,15 +1552,21 @@ static bool findMSP430Multilibs(const Driver &D,
                                 StringRef Path, const ArgList &Args,
                                 DetectedMultilibs &Result) {
   FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
-  Multilib MSP430Multilib = makeMultilib("/430");
+  Multilib WithoutExceptions = makeMultilib("/430").flag("-exceptions");
+  Multilib WithExceptions = makeMultilib("/430/exceptions").flag("+exceptions");
+
   // FIXME: when clang starts to support msp430x ISA additional logic
   // to select between multilib must be implemented
   // Multilib MSP430xMultilib = makeMultilib("/large");
 
-  Result.Multilibs.push_back(MSP430Multilib);
+  Result.Multilibs.push_back(WithoutExceptions);
+  Result.Multilibs.push_back(WithExceptions);
   Result.Multilibs.FilterOut(NonExistent);
 
   Multilib::flags_list Flags;
+  addMultilibFlag(Args.hasFlag(options::OPT_fexceptions,
+                               options::OPT_fno_exceptions, false),
+                  "exceptions", Flags);
   if (Result.Multilibs.select(Flags, Result.SelectedMultilib))
     return true;
 

clang/lib/Driver/ToolChains/MSP430.cpp

@@ -128,7 +128,7 @@ MSP430ToolChain::MSP430ToolChain(const Driver &D, const llvm::Triple &Triple,
   }
 
   SmallString<128> SysRootDir(computeSysRoot());
-  llvm::sys::path::append(SysRootDir, "lib", MultilibSuf);
+  llvm::sys::path::append(SysRootDir, "msp430-elf", "lib", MultilibSuf);
   addPathIfExists(D, SysRootDir, getFilePaths());
 }
 
@@ -138,10 +138,9 @@ std::string MSP430ToolChain::computeSysRoot() const {
 
   SmallString<128> Dir;
   if (GCCInstallation.isValid())
-    llvm::sys::path::append(Dir, GCCInstallation.getParentLibPath(), "..",
-                            GCCInstallation.getTriple().str());
+    llvm::sys::path::append(Dir, GCCInstallation.getParentLibPath(), "..");
   else
-    llvm::sys::path::append(Dir, getDriver().Dir, "..", getTriple().str());
+    llvm::sys::path::append(Dir, getDriver().Dir, "..");
 
   return std::string(Dir.str());
 }
@@ -153,7 +152,7 @@ void MSP430ToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
     return;
 
   SmallString<128> Dir(computeSysRoot());
-  llvm::sys::path::append(Dir, "include");
+  llvm::sys::path::append(Dir, "msp430-elf", "include");
   addSystemInclude(DriverArgs, CC1Args, Dir.str());
 }
 
@@ -180,6 +179,87 @@ Tool *MSP430ToolChain::buildLinker() const {
   return new tools::msp430::Linker(*this);
 }
 
+void msp430::Linker::AddStartFiles(bool UseExceptions, const ArgList &Args,
+                                   ArgStringList &CmdArgs) const {
+  const ToolChain &ToolChain = getToolChain();
+
+  CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt0.o")));
+  const char *crtbegin = UseExceptions ? "crtbegin.o" : "crtbegin_no_eh.o";
+  CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtbegin)));
+}
+
+void msp430::Linker::AddDefaultLibs(const llvm::opt::ArgList &Args,
+                                    llvm::opt::ArgStringList &CmdArgs) const {
+  const ToolChain &ToolChain = getToolChain();
+  const Driver &D = ToolChain.getDriver();
+
+  CmdArgs.push_back("--start-group");
+  CmdArgs.push_back(Args.MakeArgString(getHWMultLib(Args)));
+  CmdArgs.push_back("-lc");
+  AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+  CmdArgs.push_back("-lcrt");
+
+  if (Args.hasArg(options::OPT_msim)) {
+    CmdArgs.push_back("-lsim");
+
+    // msp430-sim.ld relies on __crt0_call_exit being implicitly .refsym-ed
+    // in main() by msp430-gcc.
+    // This workaround should work seamlessly unless the compilation unit that
+    // contains main() is compiled by clang and then passed to
+    // gcc compiler driver for linkage.
+    CmdArgs.push_back("--undefined=__crt0_call_exit");
+  } else
+    CmdArgs.push_back("-lnosys");
+
+  CmdArgs.push_back("--end-group");
+  AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+}
+
+void msp430::Linker::AddEndFiles(bool UseExceptions, const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  const ToolChain &ToolChain = getToolChain();
+  const Driver &D = ToolChain.getDriver();
+
+  const char *crtend = UseExceptions ? "crtend.o" : "crtend_no_eh.o";
+  CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtend)));
+  AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+}
+
+static void AddSspArgs(const ArgList &Args, ArgStringList &CmdArgs) {
+  Arg *SspFlag = Args.getLastArg(
+      options::OPT_fno_stack_protector, options::OPT_fstack_protector,
+      options::OPT_fstack_protector_all, options::OPT_fstack_protector_strong);
+
+  if (SspFlag &&
+      !SspFlag->getOption().matches(options::OPT_fno_stack_protector)) {
+    CmdArgs.push_back("-lssp_nonshared");
+    CmdArgs.push_back("-lssp");
+  }
+}
+
+static void AddImplicitLinkerScript(const std::string SysRoot,
+                                    const ArgList &Args,
+                                    ArgStringList &CmdArgs) {
+  if (Args.hasArg(options::OPT_T))
+    return;
+
+  if (Args.hasArg(options::OPT_msim)) {
+    CmdArgs.push_back("-Tmsp430-sim.ld");
+    return;
+  }
+
+  const Arg *MCUArg = Args.getLastArg(options::OPT_mmcu_EQ);
+  if (!MCUArg)
+    return;
+
+  SmallString<128> MCULinkerScriptPath(SysRoot);
+  llvm::sys::path::append(MCULinkerScriptPath, "include");
+  // -L because <mcu>.ld INCLUDEs <mcu>_symbols.ld
+  CmdArgs.push_back(Args.MakeArgString("-L" + MCULinkerScriptPath));
+  CmdArgs.push_back(
+      Args.MakeArgString("-T" + StringRef(MCUArg->getValue()) + ".ld"));
+}
+
 void msp430::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                   const InputInfo &Output,
                                   const InputInfoList &Inputs,
@@ -189,44 +269,49 @@ void msp430::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   const Driver &D = ToolChain.getDriver();
   std::string Linker = ToolChain.GetProgramPath(getShortName());
   ArgStringList CmdArgs;
-
-  if (!D.SysRoot.empty())
-    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+  bool UseExceptions = Args.hasFlag(options::OPT_fexceptions,
+                                    options::OPT_fno_exceptions, false);
+  bool UseStartAndEndFiles = !Args.hasArg(options::OPT_nostdlib, options::OPT_r,
+                                          options::OPT_nostartfiles);
+
+  if (Args.hasArg(options::OPT_mrelax))
+    CmdArgs.push_back("--relax");
+  if (!Args.hasArg(options::OPT_r, options::OPT_g_Group))
+    CmdArgs.push_back("--gc-sections");
+
+  Args.AddAllArgs(CmdArgs, {
+                               options::OPT_e,
+                               options::OPT_n,
+                               options::OPT_s,
+                               options::OPT_t,
+                               options::OPT_u,
+                           });
+
+  if (UseStartAndEndFiles)
+    AddStartFiles(UseExceptions, Args, CmdArgs);
 
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
-
-  if (!Args.hasArg(options::OPT_T)) {
-    if (const Arg *MCUArg = Args.getLastArg(options::OPT_mmcu_EQ))
-      CmdArgs.push_back(
-          Args.MakeArgString("-T" + StringRef(MCUArg->getValue()) + ".ld"));
-  } else {
-    Args.AddAllArgs(CmdArgs, options::OPT_T);
-  }
-
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
-    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt0.o")));
-    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtbegin.o")));
-  }
-
   AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
 
-  CmdArgs.push_back("--start-group");
-  CmdArgs.push_back(Args.MakeArgString(getHWMultLib(Args)));
-  CmdArgs.push_back("-lgcc");
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
-    CmdArgs.push_back("-lc");
-    CmdArgs.push_back("-lcrt");
-    CmdArgs.push_back("-lnosys");
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_r,
+                   options::OPT_nodefaultlibs)) {
+    AddSspArgs(Args, CmdArgs);
+    AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+    if (!Args.hasArg(options::OPT_nolibc)) {
+      AddDefaultLibs(Args, CmdArgs);
+      AddImplicitLinkerScript(D.SysRoot, Args, CmdArgs);
+    }
   }
-  CmdArgs.push_back("--end-group");
 
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
-    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtend.o")));
-    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
-  }
+  if (UseStartAndEndFiles)
+    AddEndFiles(UseExceptions, Args, CmdArgs);
+
   CmdArgs.push_back("-o");
   CmdArgs.push_back(Output.getFilename());
+
+  Args.AddAllArgs(CmdArgs, options::OPT_T);
+
   C.addCommand(
       std::make_unique<Command>(JA, *this, ResponseFileSupport::AtFileCurCP(),
                                 Args.MakeArgString(Linker), CmdArgs, Inputs));

clang/lib/Driver/ToolChains/MSP430.h

@@ -40,6 +40,11 @@ class LLVM_LIBRARY_VISIBILITY MSP430ToolChain : public Generic_ELF {
   bool isPIEDefault() const override { return false; }
   bool isPICDefaultForced() const override { return true; }
 
+  UnwindLibType
+  GetUnwindLibType(const llvm::opt::ArgList &Args) const override {
+    return UNW_None;
+  }
+
 protected:
   Tool *buildLinker() const override;
 
@@ -61,6 +66,14 @@ class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
                     const InputInfo &Output, const InputInfoList &Inputs,
                     const llvm::opt::ArgList &TCArgs,
                     const char *LinkingOutput) const override;
+
+private:
+  void AddStartFiles(bool UseExceptions, const llvm::opt::ArgList &Args,
+                     llvm::opt::ArgStringList &CmdArgs) const;
+  void AddDefaultLibs(const llvm::opt::ArgList &Args,
+                      llvm::opt::ArgStringList &CmdArgs) const;
+  void AddEndFiles(bool UseExceptions, const llvm::opt::ArgList &Args,
+                   llvm::opt::ArgStringList &CmdArgs) const;
 };
 
 void getMSP430TargetFeatures(const Driver &D, const llvm::opt::ArgList &Args,