[LLDB] Pass const RegisterInfo& to RegisterValue::SetValueFromData

[DavidSpickett]

Summary

Familiar story, callers are either checking upfront that the pointer
wasn't null or not checking at all. SetValueFromData itself didn't
check either.

So make the parameter a ref and fixup the few places where a nullptr
check seems needed.

Depends on D135668

lldb/include/lldb/Utility/RegisterValue.h

public:
 
   bool SignExtend(uint32_t sign_bitpos);
 
   Status SetValueFromString(const RegisterInfo *reg_info,
                             llvm::StringRef value_str);
   Status SetValueFromString(const RegisterInfo *reg_info,
                             const char *value_str) = delete;
 
-  Status SetValueFromData(const RegisterInfo *reg_info, DataExtractor &data,
+  Status SetValueFromData(const RegisterInfo &reg_info, DataExtractor &data,
                           lldb::offset_t offset, bool partial_data_ok);
 
   const void *GetBytes() const;
 
   lldb::ByteOrder GetByteOrder() const {
     if (m_type == eTypeBytes)
       return buffer.byte_order;
     return endian::InlHostByteOrder();

lldb/source/Core/ValueObjectRegister.cpp

if (!m_reg_ctx_sp->WriteRegister(&m_reg_info, m_reg_value)) {
     return false;
   }
 
   SetNeedsUpdate();
   return true;
 }
 
 bool ValueObjectRegister::SetData(DataExtractor &data, Status &error) {
-  error = m_reg_value.SetValueFromData(&m_reg_info, data, 0, false);
+  error = m_reg_value.SetValueFromData(m_reg_info, data, 0, false);
   if (!error.Success())
     return false;
 
   if (!m_reg_ctx_sp->WriteRegister(&m_reg_info, m_reg_value)) {
     error.SetErrorString("unable to write back to register");
     return false;
   }
 

lldb/source/Core/ValueObjectVariable.cpp

if (m_resolved_value.GetContextType() == Value::ContextType::RegisterInfo) {
     RegisterInfo *reg_info = m_resolved_value.GetRegisterInfo();
     ExecutionContext exe_ctx(GetExecutionContextRef());
     RegisterContext *reg_ctx = exe_ctx.GetRegisterContext();
     RegisterValue reg_value;
     if (!reg_info || !reg_ctx) {
       error.SetErrorString("unable to retrieve register info");
       return false;
     }
-    error = reg_value.SetValueFromData(reg_info, data, 0, true);
+    error = reg_value.SetValueFromData(*reg_info, data, 0, true);
     if (error.Fail())
       return false;
     if (reg_ctx->WriteRegister(reg_info, reg_value)) {
       SetNeedsUpdate();
       return true;
     } else {
       error.SetErrorString("unable to write back to register");
       return false;
     }
   } else
     return ValueObject::SetData(data, error);
 }

lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp

if (type_flags & eTypeIsScalar || type_flags & eTypeIsPointer) {
               "returning complex float values are not supported");
         } else {
           const RegisterInfo *v0_info = reg_ctx->GetRegisterInfoByName("v0", 0);
 
           if (v0_info) {
             if (byte_size <= 16) {
               if (byte_size <= RegisterValue::GetMaxByteSize()) {
                 RegisterValue reg_value;
-                error = reg_value.SetValueFromData(v0_info, data, 0, true);
+                error = reg_value.SetValueFromData(*v0_info, data, 0, true);
                 if (error.Success()) {
                   if (!reg_ctx->WriteRegister(v0_info, reg_value))
                     error.SetErrorString("failed to write register v0");
                 }
               } else {
                 error.SetErrorStringWithFormat(
                     "returning float values with a byte size of %" PRIu64
                     " are not supported",
if (type_flags & eTypeIsScalar || type_flags & eTypeIsPointer) {
       }
     } else if (type_flags & eTypeIsVector) {
       if (byte_size > 0) {
         const RegisterInfo *v0_info = reg_ctx->GetRegisterInfoByName("v0", 0);
 
         if (v0_info) {
           if (byte_size <= v0_info->byte_size) {
             RegisterValue reg_value;
-            error = reg_value.SetValueFromData(v0_info, data, 0, true);
+            error = reg_value.SetValueFromData(*v0_info, data, 0, true);
             if (error.Success()) {
               if (!reg_ctx->WriteRegister(v0_info, reg_value))
                 error.SetErrorString("failed to write register v0");
             }
           }
         }
       }
     }

lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.cpp

if (type_flags & eTypeIsScalar || type_flags & eTypeIsPointer) {
               "returning complex float values are not supported");
         } else {
           const RegisterInfo *v0_info = reg_ctx->GetRegisterInfoByName("v0", 0);
 
           if (v0_info) {
             if (byte_size <= 16) {
               if (byte_size <= RegisterValue::GetMaxByteSize()) {
                 RegisterValue reg_value;
-                error = reg_value.SetValueFromData(v0_info, data, 0, true);
+                error = reg_value.SetValueFromData(*v0_info, data, 0, true);
                 if (error.Success()) {
                   if (!reg_ctx->WriteRegister(v0_info, reg_value))
                     error.SetErrorString("failed to write register v0");
                 }
               } else {
                 error.SetErrorStringWithFormat(
                     "returning float values with a byte size of %" PRIu64
                     " are not supported",
if (type_flags & eTypeIsScalar || type_flags & eTypeIsPointer) {
       }
     } else if (type_flags & eTypeIsVector) {
       if (byte_size > 0) {
         const RegisterInfo *v0_info = reg_ctx->GetRegisterInfoByName("v0", 0);
 
         if (v0_info) {
           if (byte_size <= v0_info->byte_size) {
             RegisterValue reg_value;
-            error = reg_value.SetValueFromData(v0_info, data, 0, true);
+            error = reg_value.SetValueFromData(*v0_info, data, 0, true);
             if (error.Success()) {
               if (!reg_ctx->WriteRegister(v0_info, reg_value))
                 error.SetErrorString("failed to write register v0");
             }
           }
         }
       }
     }

lldb/source/Plugins/Process/Utility/RegisterContextMemory.cpp

bool RegisterContextMemory::ReadRegister(const RegisterInfo *reg_info,
                                          RegisterValue &reg_value) {
   const uint32_t reg_num = reg_info->kinds[eRegisterKindLLDB];
   if (!m_reg_valid[reg_num]) {
     if (!ReadAllRegisterValues(m_data))
       return false;
   }
   const bool partial_data_ok = false;
   return reg_value
-      .SetValueFromData(reg_info, m_reg_data, reg_info->byte_offset,
+      .SetValueFromData(*reg_info, m_reg_data, reg_info->byte_offset,
                         partial_data_ok)
       .Success();
 }
 
 bool RegisterContextMemory::WriteRegister(const RegisterInfo *reg_info,
                                           const RegisterValue &reg_value) {
   if (m_reg_data_addr != LLDB_INVALID_ADDRESS) {
     const uint32_t reg_num = reg_info->kinds[eRegisterKindLLDB];

lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp

if (reg_info->value_regs &&
 
       Status error;
       return value.SetFromMemoryData(
                  *reg_info, combined_data.data(), combined_data.size(),
                  m_reg_data.GetByteOrder(), error) == combined_data.size();
     } else {
       const bool partial_data_ok = false;
       Status error(value.SetValueFromData(
-          reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
+          *reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
       return error.Success();
     }
   }
   return false;
 }
 
 bool GDBRemoteRegisterContext::PrivateSetRegisterValue(
     uint32_t reg, llvm::ArrayRef<uint8_t> data) {

lldb/source/Utility/RegisterValue.cpp

error.SetErrorStringWithFormat(
         reg_info.name, dst_len);
     return 0;
   }
 
   // Use a data extractor to correctly copy and pad the bytes read into the
   // register value
   DataExtractor src_data(src, src_len, src_byte_order, 4);
 
-  error = SetValueFromData(&reg_info, src_data, 0, true);
+  error = SetValueFromData(reg_info, src_data, 0, true);
   if (error.Fail())
     return 0;
 
   // If SetValueFromData succeeded, we must have copied all of src_len
   return src_len;
 }
 
 bool RegisterValue::GetScalarValue(Scalar &scalar) const {
case eTypeLongDouble:
     return true;
   }
   return false;
 }
 
 void RegisterValue::Clear() { m_type = eTypeInvalid; }
 
 RegisterValue::Type RegisterValue::SetType(const RegisterInfo *reg_info) {
+  assert(reg_info && "Expected non null reg_info.");
   // To change the type, we simply copy the data in again, using the new format
   RegisterValue copy;
   DataExtractor copy_data;
-  if (copy.CopyValue(*this) && copy.GetData(copy_data))
-    SetValueFromData(reg_info, copy_data, 0, true);
+  if (copy.CopyValue(*this) && copy.GetData(copy_data)) {
+    Status error = SetValueFromData(*reg_info, copy_data, 0, true);
+    assert(error.Success() && "Expected SetValueFromData to succeed.");
+    UNUSED_IF_ASSERT_DISABLED(error);
+  }
 
   return m_type;
 }
 
-Status RegisterValue::SetValueFromData(const RegisterInfo *reg_info,
+Status RegisterValue::SetValueFromData(const RegisterInfo &reg_info,
                                        DataExtractor &src,
                                        lldb::offset_t src_offset,
                                        bool partial_data_ok) {
   Status error;
 
   if (src.GetByteSize() == 0) {
     error.SetErrorString("empty data.");
     return error;
   }
 
-  if (reg_info->byte_size == 0) {
+  if (reg_info.byte_size == 0) {
     error.SetErrorString("invalid register info.");
     return error;
   }
 
   uint32_t src_len = src.GetByteSize() - src_offset;
 
-  if (!partial_data_ok && (src_len < reg_info->byte_size)) {
+  if (!partial_data_ok && (src_len < reg_info.byte_size)) {
     error.SetErrorString("not enough data.");
     return error;
   }
 
   // Cap the data length if there is more than enough bytes for this register
   // value
-  if (src_len > reg_info->byte_size)
-    src_len = reg_info->byte_size;
+  if (src_len > reg_info.byte_size)
+    src_len = reg_info.byte_size;
 
   // Zero out the value in case we get partial data...
   memset(buffer.bytes, 0, sizeof(buffer.bytes));
 
   type128 int128;
 
   m_type = eTypeInvalid;
-  switch (reg_info->encoding) {
+  switch (reg_info.encoding) {
   case eEncodingInvalid:
     break;
   case eEncodingUint:
   case eEncodingSint:
-    if (reg_info->byte_size == 1)
+    if (reg_info.byte_size == 1)
       SetUInt8(src.GetMaxU32(&src_offset, src_len));
-    else if (reg_info->byte_size <= 2)
+    else if (reg_info.byte_size <= 2)
       SetUInt16(src.GetMaxU32(&src_offset, src_len));
-    else if (reg_info->byte_size <= 4)
+    else if (reg_info.byte_size <= 4)
       SetUInt32(src.GetMaxU32(&src_offset, src_len));
-    else if (reg_info->byte_size <= 8)
+    else if (reg_info.byte_size <= 8)
       SetUInt64(src.GetMaxU64(&src_offset, src_len));
-    else if (reg_info->byte_size <= 16) {
+    else if (reg_info.byte_size <= 16) {
       uint64_t data1 = src.GetU64(&src_offset);
       uint64_t data2 = src.GetU64(&src_offset);
       if (src.GetByteSize() == eByteOrderBig) {
         int128.x[0] = data1;
         int128.x[1] = data2;
       } else {
         int128.x[0] = data2;
         int128.x[1] = data1;
       }
       SetUInt128(llvm::APInt(128, 2, int128.x));
     }
     break;
   case eEncodingIEEE754:
-    if (reg_info->byte_size == sizeof(float))
+    if (reg_info.byte_size == sizeof(float))
       SetFloat(src.GetFloat(&src_offset));
-    else if (reg_info->byte_size == sizeof(double))
+    else if (reg_info.byte_size == sizeof(double))
       SetDouble(src.GetDouble(&src_offset));
-    else if (reg_info->byte_size == sizeof(long double))
+    else if (reg_info.byte_size == sizeof(long double))
       SetLongDouble(src.GetLongDouble(&src_offset));
     break;
   case eEncodingVector: {
     m_type = eTypeBytes;
-    buffer.length = reg_info->byte_size;
+    buffer.length = reg_info.byte_size;
     buffer.byte_order = src.GetByteOrder();
     assert(buffer.length <= kMaxRegisterByteSize);
     if (buffer.length > kMaxRegisterByteSize)
       buffer.length = kMaxRegisterByteSize;
     if (src.CopyByteOrderedData(
             src_offset,    // offset within "src" to start extracting data
             src_len,       // src length
             buffer.bytes,  // dst buffer
             buffer.length, // dst length
             buffer.byte_order) == 0) // dst byte order
     {
       error.SetErrorStringWithFormat(
-          "failed to copy data for register write of %s", reg_info->name);
+          "failed to copy data for register write of %s", reg_info.name);
       return error;
     }
   }
   }
 
   if (m_type == eTypeInvalid)
     error.SetErrorStringWithFormat(
-        "invalid register value type for register %s", reg_info->name);
+        "invalid register value type for register %s", reg_info.name);
   return error;
 }
 
 // Helper function for RegisterValue::SetValueFromString()
 static bool ParseVectorEncoding(const RegisterInfo *reg_info,
                                 llvm::StringRef vector_str,
                                 const uint32_t byte_size,
                                 RegisterValue *reg_value) {