[MIPS]Handle floating point and aggregate return types in SysV-mips [32 bit] ABI

[bhushan]

Summary

This patch adds support of floating point and aggregate return types in GetReturnValueObjectImpl() for mips32

[clayborg]

Init the variables and this is good to go.

source/Plugins/ABI/SysV-mips/ABISysV_mips.cpp

426–429

Initialize these with default values in case the code is changed/reorganized later.

[bhushan]

Addresses review comments. (Initialized variables with default values).

[clayborg]

Looks good. Feel free to also initialized "is_signed" if you can, no need for review on that change.

[bhushan]

Committed in revision 245020

source/Plugins/ABI/SysV-mips/ABISysV_mips.cpp

if (exe_ctx.GetTargetPtr() == NULL || exe_ctx.GetProcessPtr() == NULL)
         return return_valobj_sp;
 
     value.SetClangType(return_clang_type);
 
     RegisterContext *reg_ctx = thread.GetRegisterContext().get();
     if (!reg_ctx)
         return return_valobj_sp;
     
     bool is_signed;
+    bool is_complex = false;
+    uint32_t count = 0;
 
     // In MIPS register "r2" (v0) holds the integer function return values
     const RegisterInfo *r2_reg_info = reg_ctx->GetRegisterInfoByName("r2", 0);
+    size_t bit_width = return_clang_type.GetBitSize(&thread);
     
     if (return_clang_type.IsIntegerType (is_signed))
     {
-        size_t bit_width = return_clang_type.GetBitSize(&thread);
-        
         switch (bit_width)
         {
             default:
                 return return_valobj_sp;
             case 64:
             {
                 const RegisterInfo *r3_reg_info = reg_ctx->GetRegisterInfoByName("r3", 0);
                 uint64_t raw_value;
if (return_clang_type.IsIntegerType (is_signed))
                 break;
         }
     }
     else if (return_clang_type.IsPointerType ())
     {
         uint32_t ptr = thread.GetRegisterContext()->ReadRegisterAsUnsigned(r2_reg_info, 0) & UINT32_MAX;
         value.GetScalar() = ptr;
     }
+    else if (return_clang_type.IsAggregateType ())
+    {
+        // Structure/Vector is always passed in memory and pointer to that memory is passed in r2. 
+        uint64_t mem_address = reg_ctx->ReadRegisterAsUnsigned(reg_ctx->GetRegisterInfoByName("r2", 0), 0);
+        // We have got the address. Create a memory object out of it
+        return_valobj_sp = ValueObjectMemory::Create (&thread,
+                                                      "",
+                                                      Address (mem_address, NULL),
+                                                      return_clang_type);
+        return return_valobj_sp;
+    }
+    else if (return_clang_type.IsFloatingPointType (count, is_complex))
+    {
+        const RegisterInfo *f0_info = reg_ctx->GetRegisterInfoByName("f0", 0);
+        const RegisterInfo *f1_info = reg_ctx->GetRegisterInfoByName("f1", 0);
+
+        if (count == 1 && !is_complex)
+        {
+            switch (bit_width)
+            {
+                default:
+                    return return_valobj_sp;
+                case 64:
+                {
+                    static_assert(sizeof(double) == sizeof(uint64_t), "");
+                    uint64_t raw_value;
+                    raw_value = reg_ctx->ReadRegisterAsUnsigned(f0_info, 0) & UINT32_MAX;
+                    raw_value |= ((uint64_t)(reg_ctx->ReadRegisterAsUnsigned(f1_info, 0) & UINT32_MAX)) << 32;
+                    value.GetScalar() = *reinterpret_cast<double*>(&raw_value);
+                    break;
+                }
+                case 32:
+                {
+                    static_assert(sizeof(float) == sizeof(uint32_t), "");
+                    uint32_t raw_value = reg_ctx->ReadRegisterAsUnsigned(f0_info, 0) & UINT32_MAX;
+                    value.GetScalar() = *reinterpret_cast<float*>(&raw_value);
+                    break;
+                }
+            }
+        }
+        else
+        {
+            // not handled yet
+            return return_valobj_sp;
+        }
+    }
     else
     {
         // not handled yet
         return return_valobj_sp;
     }
     
     // If we get here, we have a valid Value, so make our ValueObject out of it: