Difference between revisions of "WebAssembly/Compiler"

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(WASI target)
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The ''llvm-mc'' assembler and ''wasm-ld'' linker. These are the assembler and linker from the LLVM project.
 
The ''llvm-mc'' assembler and ''wasm-ld'' linker. These are the assembler and linker from the LLVM project.
  
=== Compiling the compiler ===
+
=== Obtaining the compiler sources ===
  
 
Get the sources:
 
Get the sources:
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enter the directory:
 
enter the directory:
 
  cd fpc-wasm
 
  cd fpc-wasm
 +
 +
=== Supported targets ===
  
 
==== WASI target ====
 
==== WASI target ====

Revision as of 05:18, 31 January 2021

Instructions

Prerequisites

The llvm-mc assembler and wasm-ld linker. These are the assembler and linker from the LLVM project.

Obtaining the compiler sources

Get the sources:

svn checkout https://svn.freepascal.org/svn/fpc/branches/wasm/ fpc-wasm

enter the directory:

cd fpc-wasm

Supported targets

WASI target

make all OS_TARGET=wasi CPU_TARGET=wasm32 BINUTILSPREFIX= OPT="-O-" PP=fpc

Currently, it reaches the point, where it fails with this error:

globals.pas(40,7) Fatal: Can't find unit sysutils used by globals
Fatal: Compilation aborted

This is because the sysutils hasn't been ported to the WASI target, yet. If compilation reaches this point, you can still compile 'Hello, world!'. The following units have been ported for the WASI target:

  • system
  • objpas
  • ctypes
  • strings
  • wasiapi - interface for the WASI API

Embedded target

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 wasm-wasm-wasmld to wasmld, and wasm-wasm-wasmtool to wasmtool.

wasm-demo

Wasm-demo is a Pascal WebAssembly demo project, ported Google's C WebAssembly example (https://codelabs.developers.google.com/codelabs/web-assembly-intro)

You follow these steps in order to get the demo project working:

1. Get the project sources: https://github.com/skalogryz/wasm-demo

Using in webassembly.studio

2. Run the wasm compiler against lyff.pas, but request the assembler file to be kept

 pp -a lyff.pas

Webassembly.studio accepts the assembler file and would compile it on the server side.

3. open up https://webassembly.studio and select "Create empty Wat Project". The project will consist of:

main.html
main.js
main.wat

All files of the project can be edited through the web interface.

4. Copy and paste the contents of the following files:

(compiled) lyff.wat to main.wat.
wasm-demo\webassembly.studio\main.html to main.html
wasm-demo\webassembly.studio\main.js to main.js

Note: every time you copy and paste, don't forget to press "SAVE" button (on the right side of the web interface)

5. once all files are update, hit "Build and Run"

See Also