mirror of
https://github.com/mruby/mruby
synced 2026-06-08 16:11:16 +00:00
Yukihiro "Matz" Matsumoto
ca364e3f3e
Enable -fwasm-exceptions and -sSUPPORT_LONGJMP=wasm for the Emscripten toolchain. This implements setjmp/longjmp using native WebAssembly exception handling instructions instead of Asyncify-based emulation. Benefits: - Minimal memory overhead (no shadow stack buffer needed) - No code size penalty - Works with both C and C++ code WASM exception handling is supported by all major browsers since 2021-2022 (Chrome 95+, Firefox 100+, Safari 15.2+) and standalone runtimes (Node.js 17+, Wasmtime, Wasmer). For older runtimes, users can override with CFLAGS/LDFLAGS environment variables. Co-authored-by: Claude <noreply@anthropic.com>
58 lines
1.6 KiB
Ruby
58 lines
1.6 KiB
Ruby
MRuby::Toolchain.new(:emscripten) do |conf|
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toolchain :clang
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# See:
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# - https://emscripten.org/docs/tools_reference/emcc.html
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# - https://emscripten.org/docs/tools_reference/settings_reference.html
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# - https://github.com/emscripten-core/emscripten/blob/main/src/settings.js
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#
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# == WASM Exception Handling ==
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#
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# mruby uses setjmp/longjmp for non-local exits (exceptions, break/return
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# from blocks). This toolchain uses native WASM exception handling which
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# is more efficient than Asyncify-based emulation:
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#
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# - Minimal memory overhead (no shadow stack)
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# - No code size penalty
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# - Works with both C and C++ code
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#
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# Supported runtimes (as of 2024):
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# - Chrome 95+, Firefox 100+, Safari 15.2+
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# - Node.js 17+, Wasmtime, Wasmer
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#
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# For older runtimes, override with CFLAGS/LDFLAGS environment variables.
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#
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# See: https://emscripten.org/docs/porting/exceptions.html
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# https://emscripten.org/docs/porting/setjmp-longjmp.html
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compile_and_link_flags = [
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'-fwasm-exceptions',
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]
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compile_flags = [
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*compile_and_link_flags,
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'-Wno-unused-but-set-variable',
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]
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link_flags = [
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*compile_and_link_flags,
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'-sSUPPORT_LONGJMP=wasm',
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]
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conf.cc do |cc|
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cc.command = 'emcc'
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cc.flags.concat(compile_flags) unless ENV['CFLAGS']
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end
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conf.cxx do |cxx|
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cxx.command = 'em++'
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cxx.flags.concat(compile_flags) unless ENV['CXXFLAGS'] || ENV['CFLAGS']
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end
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conf.linker do |linker|
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linker.command = 'emcc'
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linker.flags.concat(link_flags) unless ENV['LDFLAGS']
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end
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conf.archiver do |archiver|
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archiver.command = 'emar'
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end
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end
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