[LLDB][MIPS] Provide ABI string to compiler for appropriate code generation for MIPS

[nitesh.jain]

Summary

These patch will set clang::TargetOptions::ABI and accordingly code will be generated For MIPS target.

[nitesh.jain]

Corrected formatting issue

[clayborg]

I question if ArchSpec::GetClangTargetABI() belongs in ArchSpec. It is very clang specific. Should this just be a function in ClangExpressionParser? Like:

static std::string
ClangExpressionParser::GetTargetABI (const ArchSpec &arch);

If no where else will require this target ABI, then this probably should not live in ArchSpec.

[nitesh.jain]

Yes this function is clang specific(even GetClangTargetCPU) .Will update the diff as per suggestion.

Thanks

[nitesh.jain]

The diff is updated as per suggestion

[nitesh.jain]

Committed in revision 269407

include/lldb/Core/ArchSpec.h

public:
     ///
     /// @return A string representing target CPU for the current
     ///         architecture.
     //------------------------------------------------------------------
     std::string
     GetClangTargetCPU ();
 
     //------------------------------------------------------------------
+    /// Returns a string representing current ABI
+    ///
+    /// @return A string representing target ABI for the current
+    ///         architecture
+    //-----------------------------------------------------------------
+    std::string
+    GetClangTargetABI ();
+
+    //------------------------------------------------------------------
     /// Clears the object state.
     ///
     /// Clears the object state back to a default invalid state.
     //------------------------------------------------------------------
     void
     Clear ();
 
     //------------------------------------------------------------------

source/Core/ArchSpec.cpp

 {
     const CoreDefinition *core_def = FindCoreDefinition (m_core);
     if (core_def)
         return core_def->name;
     return "unknown";
 }
 
 std::string
+ArchSpec::GetClangTargetABI ()
+{   std::string abi;
+    const llvm::Triple::ArchType machine = GetMachine();
+
+    if (machine == llvm::Triple::mips ||
+        machine == llvm::Triple::mipsel ||
+        machine == llvm::Triple::mips64 ||
+        machine == llvm::Triple::mips64el)
+    {
+        switch (GetFlags () & eMIPSABI_mask)
+        {
+        case eMIPSABI_N64:
+             abi = "n64"; break;
+        case eMIPSABI_N32:
+             abi = "n32"; break;
+        case eMIPSABI_O32:
+             abi = "o32"; break;
+        default:
+               break;
+        }
+    }
+    return abi;
+}
+ 
+std::string
 ArchSpec::GetClangTargetCPU ()
 {
     std::string cpu;
     const llvm::Triple::ArchType machine = GetMachine();
 
     if (machine == llvm::Triple::mips ||
         machine == llvm::Triple::mipsel ||
         machine == llvm::Triple::mips64 ||

source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp

ClangExpressionParser::ClangExpressionParser (ExecutionContextScope *exe_scope,
     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
 
     // 1. Create a new compiler instance.
     m_compiler.reset(new CompilerInstance());
     lldb::LanguageType frame_lang = expr.Language(); // defaults to lldb::eLanguageTypeUnknown
     bool overridden_target_opts = false;
     lldb_private::LanguageRuntime *lang_rt = nullptr;
     lldb::TargetSP target_sp;
+    std::string abi;
     if (exe_scope)
         target_sp = exe_scope->CalculateTarget();
 
     ArchSpec target_arch;
     if (target_sp)
         target_arch = target_sp->GetArchitecture();
 
     const auto target_machine = target_arch.GetMachine();
if (target_machine == llvm::Triple::x86 ||
         m_compiler->getTargetOpts().Features.push_back("+sse");
         m_compiler->getTargetOpts().Features.push_back("+sse2");
     }
 
     // Set the target CPU to generate code for.
     // This will be empty for any CPU that doesn't really need to make a special CPU string.
     m_compiler->getTargetOpts().CPU = target_arch.GetClangTargetCPU();
 
+    // Set the target ABI
+    abi = target_arch.GetClangTargetABI();
+    if (!abi.empty())
+        m_compiler->getTargetOpts().ABI=abi;
+
     // 3. Now allow the runtime to provide custom configuration options for the target.
     // In this case, a specialized language runtime is available and we can query it for extra options.
     // For 99% of use cases, this will not be needed and should be provided when basic platform detection is not enough.
     if (lang_rt)
         overridden_target_opts = lang_rt->GetOverrideExprOptions(m_compiler->getTargetOpts());
 
     if (overridden_target_opts)
         if (log)