WebAssembly/Compiler
Prerequisites
The linker wasm-ld from the LLVM project. LLVM 11.0 and 12.0.1 are known to work.
Fedora
Development was done, using the Fedora packages llvm-11.0.0-1.fc33.x86_64 and lld-11.0.0-1.fc33.x86_64.
Ubuntu
Tested on Ubuntu 20.04. wasm-ld is part of package lld-12. Install it and set necessary symlinks:
% sudo apt install lld-12 % ln -sf /usr/lib/llvm-12/bin/wasm-ld ~/bin/wasm32-wasi-wasm-ld % ln -sf /usr/lib/llvm-12/bin/wasm-ld ~/bin/wasm32-embedded-wasm-ld
Note: This assumes you have a $HOME/bin directory and it is in PATH.
macOS
Catalina
Tested on macOS Catalina with LLVM 11. For MacPorts wasm-ld is part of package llvm-11; upon installation it exists as wasm-ld-mp-11. Install the package and set necessary symlinks:
% sudo port install llvm-11 % ln -sf /opt/local/bin/wasm-ld-mp-11 ~/bin/wasm32-wasi-wasm-ld % ln -sf /opt/local/bin/wasm-ld-mp-11 ~/bin/wasm32-embedded-wasm-ld
Note: This assumes you have a $HOME/bin directory and it is in PATH.
Monterey
Tested on macOS Monterey 12.5.1: wasm-ld is part of the official clang release for macOS: https://releases.llvm.org/download.html#11.1.0
Unpack it. When running wasm-ld, macOS might warn, that ldd cannot be verified. Open the System Preferences / Security / General. There should be ldd, unlock, then click Open Anyway.
Windows 10
Tested on Windows 10 Home 21H2. Download the LLVM 12.0.1 64-bit Windows installer. You are encouraged to verify the GPG signature on the installer. As administrator, run the installer. Let's say you installed into C:\llvm. Enable Windows 'developer mode' if you have not done so. Then set necessary symlinks:
C:\> cd llvm\bin C:\llvm\bin> mklink wasm32-wasi-wasm-ld.exe wasm-ld.exe C:\llvm\bin> mklink wasm32-embedded-wasm-ld.exe wasm-ld.exe
Add C:\llvm\bin to your PATH.
Obtaining the compiler sources
Linux and macOS
The WebAssembly compiler target is part of the 'main' branch of the GitLab FPC source repo. Get the source:
% git clone https://gitlab.com/freepascal.org/fpc/source.git fpc
Enter the sources directory:
% cd fpc
Windows
The WebAssembly compiler target is part of the 'main' branch of the GitLab FPC source repo. Get the source:
C:\Users\OnlyMe> git clone https://gitlab.com/freepascal.org/fpc/source.git fpc
Enter the sources directory:
C:\Users\OnlyMe> cd fpc
Building and installing
If you are new to building the compiler, see Installing the Free Pascal Compiler and Cross compiling.
FPC supports two WebAssembly compilation targets: WASI and embedded.
Compilation target: WASI
Linux and macOS
Build the compiler and FPC units for the WASI target:
% make clean all OS_TARGET=wasi CPU_TARGET=wasm32 BINUTILSPREFIX= OPT="-O-" PP=fpc
Then, install, using INSTALL_PREFIX to specify a destination within your home directory:
% make crossinstall OS_TARGET=wasi CPU_TARGET=wasm32 INSTALL_PREFIX=$HOME/fpcwasm
Note: On macOS you might have to add -XR/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk to OPT.
Make a link to the cross compiler executable ppcrosswasm32:
% ln -sf ~/fpcwasm/lib/fpc/3.3.1/ppcrosswasm32 ~/bin/ppcrosswasm32
Note: This assumes you have a $HOME/bin directory and it is in PATH.
Windows
Make sure the Windows native compiler fpc.exe and the FPC-bundled make.exe are in your PATH. Especially ensure that the FPC make.exe comes first in your PATH; using another make.exe (such as the one installed by Delphi) that happens to be ahead in PATH may not work.
Build the compiler and FPC units for the WASI target:
C:\Users\OnlyMe\fpc> make clean all OS_TARGET=wasi CPU_TARGET=wasm32 BINUTILSPREFIX= OPT="-O-" PP=fpc
Then, install, using INSTALL_PREFIX to specify a destination folder:
C:\Users\OnlyMe\fpc> make crossinstall OS_TARGET=wasi CPU_TARGET=wasm32 INSTALL_PREFIX=c:\fpcwasm PP=fpc
Add C:\fpcwasm\bin\x86_64-win64 to your PATH to easily run the compiler ppcrosswasm32.exe.
Compilation target: Embedded
Linux and macOS
Build the compiler and FPC units for the 'embedded' target:
% make clean all OS_TARGET=embedded CPU_TARGET=wasm32 BINUTILSPREFIX= OPT="-O-" PP=fpc
Then, install, using INSTALL_PREFIX to specify a destination within your home directory:
% make crossinstall OS_TARGET=embedded CPU_TARGET=wasm32 INSTALL_PREFIX=$HOME/fpcwasm
If you have not built and installed the WASI cross compiler, then make a link to the cross compiler executable ppcrosswasm32;
% ln -sf ~/fpcwasm/lib/fpc/3.3.1/ppcrosswasm32 ~/bin/ppcrosswasm32
Note: This assumes you have a $HOME/bin directory and it is in PATH.
Windows
Make sure the Windows native compiler fpc.exe and the FPC-bundled make.exe are in your PATH. Especially ensure that the FPC make.exe comes first in your PATH; using another make.exe (such as the one installed by Delphi) that happens to be ahead in PATH may not work.
Build the compiler and FPC units for the 'embedded' target:
C:\Users\OnlyMe\fpc> make clean all OS_TARGET=embedded CPU_TARGET=wasm32 BINUTILSPREFIX= OPT="-O-" PP=fpc
Then, install, using INSTALL_PREFIX to specify a destination folder:
C:\Users\OnlyMe\fpc> make crossinstall OS_TARGET=embedded CPU_TARGET=wasm32 INSTALL_PREFIX=c:\fpcwasm PP=fpc
Add C:\fpcwasm\bin\x86_64-win64 to your PATH if you have not already done so.
Using the compiler
For Linux and macOS, if you have installed the cross compiler and units into $HOME/fpcwasm (as per the commands used above), then you need to configure $HOME/.fpc.cfg so that the cross compiler can locate its units.
For Ubuntu, add these lines:
#ifdef cpuwasm32 -Fu/home/yourusername/fpcwasm/lib/fpc/$fpcversion/units/$fpctarget/* -Fu/home/yourusername/fpcwasm/lib/fpc/$fpcversion/units/$fpctarget/rtl #endif
For macOS, add these lines:
#ifdef cpuwasm32 -Fu/Users/yourusername/fpcwasm/lib/fpc/$fpcversion/units/$fpctarget/* -Fu/Users/yourusername/fpcwasm/lib/fpc/$fpcversion/units/$fpctarget/rtl #endif
On Windows, if you have set C:\fpcwasm\bin\x86_64-win64 directory in your PATH, then ppcrosswasm32.exe will be able to find its units.
Using the compiler with Lazarus
When you create a new Lazarus project for a wasm program you can use the Simple Program template and then adjust the Project / Project Options / Compiler Options:
- Paths / Target file name: Lazarus 2.3.0 (Dec 28th 2021) appends the required .wasm file extension to the output file. To support older IDEs disable Apply conventions and set <programname>.wasm.
- Config and Target / Target platform:
- Target OS: Wasi
- Target CPU: wasm32
- Debugging / Generate info for debugger: disable (Dec 28th 2021: otherwise you will get can't find unit linfodwrf)
- Compiler Commands / Compiler / Command: If you are using different fpc versions / folders you can here set the path to ppcrosswasm32 (e.g. Linux: /usr/lib/fpc/3.3.1/ppcrosswasm32)
