This repository has some Ewasm contracts written in C.
Get dependencies.
# hopefully you have llvm 8+, check:
clang --version
# if not
make llvm-install # should do this manually since it may need a restart. Copy the Makefile recipe or see LLVM getting started website.
# Note: LLVM version 8+ support Wasm by default. Earlier versions must be compiled with experimental wasm flag, and have different linker. We use the linker from LLVM 8+.
# install everything else
make install
# or install things individually
make wabt-install
make binaryen-install
make pywebassembly-install
# you can also install things anywhere in your system, and update paths in the Makefile or as arguments
Compile stuff.
# compile contracts in src/
make all
# compile individual project with a recipe in the Makefile
make blake2b_ref
# compile arbitrary my_contract.c
make PROJECT=my_contract SRC_DIR=path/to/my_contract/src/dir
# compile with custom tool directories
make WABT_DIR=path/to/wabt/build/ LLVM_DIR=path/to/llvm/binaries PROJECT=mul256
# clean up
make clean
WARNING: Ewasm is not yet finalized. This toolchain is changing. There are experiments in the src directory.
NOTE ABOUT C++: Basic things like std::vector require memory managment, which most standard C++ libraries implement as system calls. Ewasm doesn't support system calls, so memory management must be done in Wasm. So far, a custom malloc() is in ewasm.h, but other things are still needed before we can try to compile against C++ standard library without requiring system calls.