Fix handling of wasm import modules and names #67363
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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 rust-lang#50021 Closes rust-lang#56309 Closes rust-lang#63562 [1]: https://bugs.llvm.org/show_bug.cgi?id=44316
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…=eddyb 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 rust-lang#50021 Closes rust-lang#56309 Closes rust-lang#63562 [1]: https://bugs.llvm.org/show_bug.cgi?id=44316
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Rollup of 9 pull requests Successful merges: - #67321 (make htons const fn) - #67328 (Remove now-redundant range check on u128 -> f32 casts) - #67333 ([mir-opt] Fix `Inline` pass to handle inlining into `box` expressions) - #67354 (Fix pointing at arg when cause is outside of call) - #67363 (Fix handling of wasm import modules and names) - #67382 (Remove some unnecessary `ATTR_*` constants.) - #67389 (Remove `SO_NOSIGPIPE` dummy variable on platforms that don't use it.) - #67393 (Enable opting out of specific default LLVM arguments.) - #67394 (Remove outdated references to @t from comments) Failed merges: r? @ghost
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…=eddyb 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 rust-lang#50021 Closes rust-lang#56309 Closes rust-lang#63562 [1]: https://bugs.llvm.org/show_bug.cgi?id=44316
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…=eddyb 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 rust-lang#50021 Closes rust-lang#56309 Closes rust-lang#63562 [1]: https://bugs.llvm.org/show_bug.cgi?id=44316
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Rollup of 5 pull requests Successful merges: - #64588 (Add a raw "address of" operator) - #67031 (Update tokio crates to latest versions) - #67131 (Merge `TraitItem` & `ImplItem into `AssocItem`) - #67354 (Fix pointing at arg when cause is outside of call) - #67363 (Fix handling of wasm import modules and names) Failed merges: r? @ghost
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The wasm-bindgen nightly test suite started failing recently and a bisection shows that rust-lang/rust#67363 is the cause of this issue. The problem happening here is that after that Rust PR duplicate imports from the same name/module in different parts of a Rust program may now show up as duplicate imports rather than being coalesced into one import. This was tripping up `wasm-bindgen` which, when translating from the wasm module to wasm-bindgen's IR, is unfortunately very string-based. The fix here was to detect these duplicate imports and map them all to the same item, removing the duplicate imports. Closes rustwasm#1929
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The wasm-bindgen nightly test suite started failing recently and a bisection shows that rust-lang/rust#67363 is the cause of this issue. The problem happening here is that after that Rust PR duplicate imports from the same name/module in different parts of a Rust program may now show up as duplicate imports rather than being coalesced into one import. This was tripping up `wasm-bindgen` which, when translating from the wasm module to wasm-bindgen's IR, is unfortunately very string-based. The fix here was to detect these duplicate imports and map them all to the same item, removing the duplicate imports. Closes #1929
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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-nameattribute. This in turn leadsto 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:
All wasm symbols with
#[link(wasm_import_module = "...")]aremangled by default in LLVM IR. This means they're all given unique names.
Symbols then use the
wasm-import-nameattribute to ensure that theWebAssembly 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