clReflect: C++ Reflection using clang

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Installation Instructions

The executables in the “bin” directory can be run directly but require the MSVC 2017 x86 redistributables.

Quick Tour

clReflectTest is an up-to-date test of the clReflect library, showing how to build a database and load it at runtime.

C++ primitives are not reflected by default and need to be marked by clcpp_reflect Reflection Specs or using reflect attributes. More details can be found here.

First use clscan to parse your C++ files and output readable databases of type information:

clscan.exe test.cpp --output test.csv

Each of these databases can then be merged into one for your module using clmerge:

clmerge.exe output.csv input0.csv input1.csv input2.csv ...

Finally you can use clexport to convert this text database to a binary, memory-mapped database that can be quickly loaded by your C++ code:

clexport output.csv -cpp output.cppbin

This will give you a runtime loadable database with two limitations:

1. Functions and their parameters/return types will be reflected but their call address will not.
2. You will have to use clcpp::Database::GetType in unison with clcpp::Database::GetName to get types at runtime instead of the more efficient clcpp::GetType.

Make sure you pay attention to all reported warnings and inspect all output log files if you suspect there is a problem!

Reflecting Function Addresses

All platforms support parsing the output of your compiler’s MAP file and matching function address to their reflected equivalents in the database. Modify your clexport calls to achieve this:

clexport output.csv -cpp output.cppbin -map module.map

Constant-time, Stringless Type-of Operator

To use the constant-time, stringless GetType and GetTypeNameHash functions you need to ask clmerge to generate their implementations for you:

clmerge.exe output.csv -cpp_codegen gengettype.cpp input0.csv input1.csv input2.csv ...

Compile and link this generated C++ file with the rest of your code, load your database, call the generated initialisation function to perform one-time setup and all features of clReflect are available to you.

Matching your Compiler Settings

clscan can forward compiler options to the underlying Clang compiler. Add -- at the end of your clscan command-line and pass any options you want. For example, these are the advised command-line options for generating databases are Windows MSVC compatible:

clscan test.cpp --spec_log spec_log.txt --ast_log ast_log.txt --output test.csv -- \
-D_SCL_SECURE_NO_WARNINGS -D_CRT_SECURE_NO_WARNINGS -D__clcpp_parse__ \
-fdiagnostics-format=msvc -fms-extensions -fms-compatibility -mms-bitfields -fdelayed-template-parsing -std=c++17 -fno-rtti