43d1532cd7
Fix handling of wasm import modules and names The WebAssembly targets of rustc have weird issues around name mangling and import the same name from different modules. This all largely stems from the fact that we're using literal symbol names in LLVM IR to represent what a function is called when it's imported, and we're not using the wasm-specific `wasm-import-name` attribute. This in turn leads to two issues: * If, in the same codegen unit, the same FFI symbol is referenced twice then rustc, when translating to LLVM IR, will only reference one symbol from the first wasm module referenced. * There's also a bug in LLD [1] where even if two codegen units reference different modules, having the same symbol names means that LLD coalesces the symbols and only refers to one wasm module. Put another way, all our imported wasm symbols from the environment are keyed off their LLVM IR symbol name, which has lots of collisions today. This commit fixes the issue by implementing two changes: 1. All wasm symbols with `#[link(wasm_import_module = "...")]` are mangled by default in LLVM IR. This means they're all given unique names. 2. Symbols then use the `wasm-import-name` attribute to ensure that the WebAssembly file uses the correct import name. When put together this should ensure we don't trip over the LLD bug [1] and we also codegen IR correctly always referencing the right symbols with the right import module/name pairs. Closes #50021 Closes #56309 Closes #63562 [1]: https://bugs.llvm.org/show_bug.cgi?id=44316 |
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| assembly | ||
| auxiliary | ||
| codegen | ||
| codegen-units | ||
| compile-fail | ||
| debuginfo | ||
| incremental | ||
| mir-opt | ||
| pretty | ||
| run-fail | ||
| run-make | ||
| run-make-fulldeps | ||
| run-pass-valgrind | ||
| rustdoc | ||
| rustdoc-js | ||
| rustdoc-js-std | ||
| rustdoc-ui | ||
| rustfix | ||
| ui | ||
| ui-fulldeps | ||
| COMPILER_TESTS.md | ||