Implement __mspabi_func_epilog_N and some simulator-related options

Author: atrosinenko

clang/include/clang/Driver/Options.td

@@ -2252,6 +2252,7 @@ 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 : Joined<["-"], "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>;

clang/lib/Driver/ToolChains/MSP430.cpp

@@ -196,8 +196,17 @@ void msp430::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
 
+  // msp430gcc refs this symbol as part of epilogue of main()
+  CmdArgs.push_back("--undefined=__crt0_call_exit");
+
+  if (!Args.hasArg(options::OPT_r, options::OPT_g_Group)) {
+    CmdArgs.push_back("--gc-sections");
+  }
+
   if (!Args.hasArg(options::OPT_T)) {
-    if (const Arg *MCUArg = Args.getLastArg(options::OPT_mmcu_EQ)) {
+    if (Args.hasArg(options::OPT_msim))
+      CmdArgs.push_back("-Tmsp430-sim.ld");
+    else if (const Arg *MCUArg = Args.getLastArg(options::OPT_mmcu_EQ)) {
       SmallString<128> MCULinkerScriptPath(D.SysRoot);
       llvm::sys::path::append(MCULinkerScriptPath, "include");
       // -L because <mcu>.ld INCLUDEs <mcu>_symbols.ld
@@ -217,21 +226,24 @@ void msp430::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
 
+  // compiler-rt unit tests expect -lgcc can be disabled with -nodefaultlibs
   CmdArgs.push_back("--start-group");
   CmdArgs.push_back(Args.MakeArgString(getHWMultLib(Args)));
-  AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
     CmdArgs.push_back("-lc");
+    AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
     CmdArgs.push_back("-lcrt");
-    CmdArgs.push_back("-lnosys");
+    if (!Args.hasArg(options::OPT_msim))
+      CmdArgs.push_back("-lnosys");
   }
+  if (Args.hasArg(options::OPT_msim))
+    CmdArgs.push_back("-lsim");
   CmdArgs.push_back("--end-group");
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
     const char *crtend = Args.hasArg(options::OPT_fexceptions) ?
           "crtend.o" : "crtend_no_eh.o";
     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtend)));
-    AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
   }
   CmdArgs.push_back("-o");
   CmdArgs.push_back(Output.getFilename());

compiler-rt/lib/builtins/CMakeLists.txt

@@ -536,7 +536,10 @@ set(mips64_SOURCES ${GENERIC_TF_SOURCES}
 set(mips64el_SOURCES ${GENERIC_TF_SOURCES}
                      ${mips_SOURCES})
 
-set(msp430_SOURCES ${GENERIC_SOURCES})
+set(msp430_SOURCES
+  msp430/mspabi_func_epilog.S
+  ${GENERIC_SOURCES}
+)
 
 set(powerpc64_SOURCES
   ppc/divtc3.c

compiler-rt/lib/builtins/msp430/mspabi_func_epilog.S

@@ -0,0 +1,22 @@
+.globl __mspabi_func_epilog_7
+__mspabi_func_epilog_7:
+    pop r4
+.globl __mspabi_func_epilog_6
+__mspabi_func_epilog_6:
+    pop r5
+.globl __mspabi_func_epilog_5
+__mspabi_func_epilog_5:
+    pop r6
+.globl __mspabi_func_epilog_4
+__mspabi_func_epilog_4:
+    pop r7
+.globl __mspabi_func_epilog_3
+__mspabi_func_epilog_3:
+    pop r8
+.globl __mspabi_func_epilog_2
+__mspabi_func_epilog_2:
+    pop r9
+.globl __mspabi_func_epilog_1
+__mspabi_func_epilog_1:
+    pop r10
+    ret

compiler-rt/test/builtins/Unit/lit.cfg.py

@@ -32,6 +32,10 @@ def get_required_attr(config, attr_name):
 elif config.host_os  == 'Darwin':
   base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.osx.a ")
   config.substitutions.append( ("%librt ", base_lib + ' -lSystem ') )
+if config.target_arch.startswith("msp430"):
+  base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.builtins%s.a"
+                          % config.target_suffix)
+  config.substitutions.append( ("%librt ", "-mhwmult=none -Wl,--start-group " + base_lib + " -lc -lm -Wl,--end-group ") )
 else:
   base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.builtins%s.a"
                           % config.target_suffix)