Allow certain command line settings to be additive

For certain command line settings (specifically most settings that take
a list) it is useful to be able to add to the existing setting rather
than replace it.

For example, the `-sEXPORTED_FUNCTIONS` argument.  In a build system
where different components can inject link flags it makes sense that
each component be able add to the list of exported functions without
clobbering the current list.

We have had this feature requested several times in the past. For
example, from the bazel toolchain folks.
4 files changed
tree: b3dfbc10a984ab24cbe24139932af069408da5f3
  1. .circleci/
  2. .github/
  3. cmake/
  4. docs/
  5. media/
  6. site/
  7. src/
  8. system/
  9. test/
  10. third_party/
  11. tools/
  12. .clang-format
  13. .coveragerc
  14. .editorconfig
  15. .eslintrc.yml
  16. .flake8
  17. .gitattributes
  18. .gitignore
  19. .gitmodules
  20. .mypy.ini
  21. .prettierrc.yml
  22. .style.yapf
  23. AUTHORS
  24. ChangeLog.md
  25. CONTRIBUTING.md
  26. em++
  27. em++.bat
  28. em++.py
  29. em-config
  30. em-config.bat
  31. em-config.py
  32. emar
  33. emar.bat
  34. emar.py
  35. embuilder
  36. embuilder.bat
  37. embuilder.py
  38. emcc
  39. emcc.bat
  40. emcc.py
  41. emcmake
  42. emcmake.bat
  43. emcmake.py
  44. emconfigure
  45. emconfigure.bat
  46. emconfigure.py
  47. emdump
  48. emdump.bat
  49. emdwp
  50. emdwp.bat
  51. emmake
  52. emmake.bat
  53. emmake.py
  54. emnm
  55. emnm.bat
  56. emprofile
  57. emprofile.bat
  58. emranlib
  59. emranlib.bat
  60. emranlib.py
  61. emrun
  62. emrun.bat
  63. emrun.py
  64. emscons
  65. emscons.bat
  66. emscons.py
  67. emscripten-version.txt
  68. emscripten.py
  69. emsize
  70. emsize.bat
  71. emsize.py
  72. emstrip
  73. emstrip.bat
  74. emstrip.py
  75. emsymbolizer
  76. emsymbolizer.bat
  77. emsymbolizer.py
  78. LICENSE
  79. Makefile
  80. package-lock.json
  81. package.json
  82. README.md
  83. requirements-dev.txt
  84. SECURITY.md
README.md

emscripten logo

Main project page: https://emscripten.org

GitHub CI status: CircleCI

Chromium builder status: emscripten-releases

Overview

Emscripten compiles C and C++ to WebAssembly using LLVM and Binaryen. Emscripten output can run on the Web, in Node.js, and in wasm runtimes.

Emscripten provides Web support for popular portable APIs such as OpenGL and SDL2, allowing complex graphical native applications to be ported, such as the Unity game engine and Google Earth. It can probably port your codebase, too!

While Emscripten mostly focuses on compiling C and C++ using Clang, it can be integrated with other LLVM-using compilers (for example, Rust has Emscripten integration, with the wasm32-unknown-emscripten and asmjs-unknown-emscripten targets).

License

Emscripten is available under 2 licenses, the MIT license and the University of Illinois/NCSA Open Source License.

Both are permissive open source licenses, with little if any practical difference between them.

The reason for offering both is that (1) the MIT license is well-known and suitable for a compiler toolchain, while (2) LLVM‘s original license, the University of Illinois/NCSA Open Source License, was also offered to allow Emscripten’s code to be integrated upstream into LLVM. The second reason became less important after Emscripten switched to the LLVM wasm backend, at which point there isn't any code we expect to move back and forth between the projects; also, LLVM relicensed to Apache 2.0 + exceptions meanwhile. In practice you can just consider Emscripten as MIT licensed (which allows you to do pretty much anything you want with a compiler, including commercial and non-commercial use).

See LICENSE for the full content of the licenses.