| WebAssembly lld port |
| ==================== |
| |
| Note: The WebAssembly port is still a work in progress and is be lacking |
| certain features. |
| |
| The WebAssembly version of lld takes WebAssembly binaries as inputs and produces |
| a WebAssembly binary as its output. For the most part this port tried to mimic |
| the behaviour of traditional ELF linkers and specifically the ELF lld port. |
| Where possible that command line flags and the semantics should be the same. |
| |
| |
| Object file format |
| ------------------ |
| |
| The format the input object files that lld expects is specified as part of the |
| the WebAssembly tool conventions |
| https://github.com/WebAssembly/tool-conventions/blob/master/Linking.md. |
| |
| This is object format that the llvm will produce when run with the |
| ``wasm32-unknown-unknown`` target. To build llvm with WebAssembly support |
| currently requires enabling the experimental backed using |
| ``-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly``. |
| |
| |
| Missing features |
| ---------------- |
| |
| There are several key features that are not yet implement in the WebAssembly |
| ports: |
| |
| - COMDAT support. This means that support for C++ is still very limited. |
| - Function stripping. Currently there is no support for ``--gc-sections`` so |
| functions and data from a given object will linked as a unit. |
| - Section start/end symbols. The synthetic symbols that mark the start and |
| of data regions are not yet created in the output file. |
