The wasm-ld linker. This the linker from the LLVM project. The external assembler llvm-mc is optional, since commit bc76487b878e59133ce3c2cc19ebb13f9a9826ea, in which, the internal assembler and object writer was enabled.
LLVM 11.0 is known to work. Development was done, using the Fedora packages llvm-11.0.0-1.fc33.x86_64 and lld-11.0.0-1.fc33.x86_64. Initial tests on MacOS used llvm-11 installed with MacPorts (https://www.macports.org) and according symlinks in /opt/local/bin (wasm32-wasi-llvm-mc -> llvm-mc-mp-11 and wasm32-embedded-llvm-mc -> llvm-mc-mp-11).
LLVM 12.0.1 also works.
Obtaining the compiler sources
The WebAssembly target was merged into FPC SVN trunk in r48955 on 2021-03-14. Since then, Free Pascal has moved to GitLab, so now it's now included in the git 'main' branch.
Get the sources:
git clone https://gitlab.com/freepascal.org/fpc/source.git fpc-wasm
enter the directory:
WASI - The WebAssembly System Interface
WASI is a modular system interface for WebAssembly. It allows creating portable and secure programs that can run in a sandboxed command-line environment. See the WASI website for more information.
To build the compiler for the WASI target:
make all OS_TARGET=wasi CPU_TARGET=wasm32 BINUTILSPREFIX= OPT="-O-" PP=fpc
The following units have been ported for the WASI target:
- wasiapi - interface for the WASI API
Additionally, these units compile, but are not yet fully functional and/or tested very well:
See WebAssembly/Roadmap for details.
Compiled WASI binaries work with wasmtime version 0.23.0 or in the browser by opening:
and drag and dropping the .wasm binary directly into the browser window.
The Embedded target is primarily used for embedded systems, without an operating system. However, it also happens to be a perfect fit for creating WebAssembly modules that don't use any particular operating system-like API.
make all OS_TARGET=embedded CPU_TARGET=wasm32 BINUTILSPREFIX= OPT="-O-" PP=fpc
Using the compiler
Hint: If your fpc.cfg has
#IFDEF FPC_CROSSCOMPILING #IFDEF NEEDCROSSBINUTILS -XP$FPCTARGET- #ENDIF #ENDIF
Enclose it in #IFNDEF CPUWASM32 :
#IFDEF FPC_CROSSCOMPILING #IFDEF NEEDCROSSBINUTILS #ifndef cpuwasm32 -XP$FPCTARGET- #endif #ENDIF #ENDIF
Otherwise, you have to create symlinks wasm32-wasi-llvm-mc to llvm-mc, and wasm32-wasi-wasm-ld to wasm-ld.