-Cllvm-args usability improvement
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`-Cllvm-args` usability improvement fixes: rust-lang#26338 fixes: rust-lang#115564 Two problems were found during playing with `-Cllvm-args` 1. When `llvm.link-shared` is set to `false` in `config.toml`, output of `rustc -C llvm-args='--help-list-hidden'` doesn't contain `--emit-dwarf-unwind` and `--emulated-tls`. When it is set to `true`, `rustc -C llvm-args='--help-list-hidden'` emits `--emit-dwarf-unwind`, but `--emulated-tls` is still missing. 2. Setting `-Cllvm-args=--emit-dwarf-unwind=always` doesn't take any effect, but `-Cllvm-args=-machine-outliner-reruns=3` does work. ### 1 Adding `RegisterCodeGenFlags` to register codegen flags fixed the first problem. `rustc -C llvm-args='--help-list-hidden'` emits full codegen flags including `--emit-dwarf-unwind` and `--emulated-tls`. ### 2 Constructing `TargetOptions` from `InitTargetOptionsFromCodeGenFlags` in `LLVMRustCreateTargetMachine` fixed the second problem. The `LLVMRustSetLLVMOptions` calls `ParseCommandLineOptions` which parses given `llvm-args`. For options like `machine-outliner-reruns`, it just works, since the codegen logic directly consumes the parsing result: [machine-outliner-reruns register](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/lib/CodeGen/MachineOutliner.cpp#L114) [machine-outliner-reruns consumption](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/lib/CodeGen/MachineOutliner.cpp#L1138) But for flags defined in `TargetOptions` and `MCTargetOptions` to take effect, constructing them with `InitTargetOptionsFromCodeGenFlags` is essential, or the parsing result is just not consumed. Similar patterns can be observed in [lli](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/tools/llc/llc.cpp#L494), [llc](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/tools/lli/lli.cpp#L517), etc.
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…llaumeGomez Rollup of 8 pull requests Successful merges: - rust-lang#115345 (MCP661: Move wasm32-wasi-preview1-threads target to Tier 2) - rust-lang#115604 (rustdoc: Render private fields in tuple struct as `/* private fields */`) - rust-lang#115624 (Print the path of a return-position impl trait in trait when `return_type_notation` is enabled) - rust-lang#115629 (Don't suggest dereferencing to unsized type) - rust-lang#115633 (Lint node for `PRIVATE_BOUNDS`/`PRIVATE_INTERFACES` is the item which names the private type) - rust-lang#115634 (Use `newtype_index` for `IntVid` and `FloatVid`.) - rust-lang#115638 (`-Cllvm-args` usability improvement) - rust-lang#115649 (diagnostics: add test case for trait bounds diagnostic) r? `@ghost` `@rustbot` modify labels: rollup
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…llaumeGomez Rollup of 8 pull requests Successful merges: - rust-lang#115345 (MCP661: Move wasm32-wasi-preview1-threads target to Tier 2) - rust-lang#115604 (rustdoc: Render private fields in tuple struct as `/* private fields */`) - rust-lang#115624 (Print the path of a return-position impl trait in trait when `return_type_notation` is enabled) - rust-lang#115629 (Don't suggest dereferencing to unsized type) - rust-lang#115633 (Lint node for `PRIVATE_BOUNDS`/`PRIVATE_INTERFACES` is the item which names the private type) - rust-lang#115634 (Use `newtype_index` for `IntVid` and `FloatVid`.) - rust-lang#115638 (`-Cllvm-args` usability improvement) - rust-lang#115649 (diagnostics: add test case for trait bounds diagnostic) r? `@ghost` `@rustbot` modify labels: rollup
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…llaumeGomez Rollup of 6 pull requests Successful merges: - rust-lang#104299 (Clarify stability guarantee for lifetimes in enum discriminants) - rust-lang#115088 (Fix Step Skipping Caused by Using the `--exclude` Option) - rust-lang#115201 (rustdoc: list matching impls on type aliases) - rust-lang#115633 (Lint node for `PRIVATE_BOUNDS`/`PRIVATE_INTERFACES` is the item which names the private type) - rust-lang#115638 (`-Cllvm-args` usability improvement) - rust-lang#115643 (fix: return early when has tainted in mir-lint) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#115638 - ldm0:ldm/llvm-args-fix, r=nikic `-Cllvm-args` usability improvement fixes: rust-lang#26338 fixes: rust-lang#115564 Two problems were found during playing with `-Cllvm-args` 1. When `llvm.link-shared` is set to `false` in `config.toml`, output of `rustc -C llvm-args='--help-list-hidden'` doesn't contain `--emit-dwarf-unwind` and `--emulated-tls`. When it is set to `true`, `rustc -C llvm-args='--help-list-hidden'` emits `--emit-dwarf-unwind`, but `--emulated-tls` is still missing. 2. Setting `-Cllvm-args=--emit-dwarf-unwind=always` doesn't take any effect, but `-Cllvm-args=-machine-outliner-reruns=3` does work. ### 1 Adding `RegisterCodeGenFlags` to register codegen flags fixed the first problem. `rustc -C llvm-args='--help-list-hidden'` emits full codegen flags including `--emit-dwarf-unwind` and `--emulated-tls`. ### 2 Constructing `TargetOptions` from `InitTargetOptionsFromCodeGenFlags` in `LLVMRustCreateTargetMachine` fixed the second problem. The `LLVMRustSetLLVMOptions` calls `ParseCommandLineOptions` which parses given `llvm-args`. For options like `machine-outliner-reruns`, it just works, since the codegen logic directly consumes the parsing result: [machine-outliner-reruns register](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/lib/CodeGen/MachineOutliner.cpp#L114) [machine-outliner-reruns consumption](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/lib/CodeGen/MachineOutliner.cpp#L1138) But for flags defined in `TargetOptions` and `MCTargetOptions` to take effect, constructing them with `InitTargetOptionsFromCodeGenFlags` is essential, or the parsing result is just not consumed. Similar patterns can be observed in [lli](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/tools/llc/llc.cpp#L494), [llc](https://github.com/rust-lang/llvm-project/blob/0537f6354cffe546cbf47f6dc9c7f82e49e86cfb/llvm/tools/lli/lli.cpp#L517), etc.
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fixes: #26338
fixes: #115564
Two problems were found during playing with
-Cllvm-argsllvm.link-sharedis set tofalseinconfig.toml, output ofrustc -C llvm-args='--help-list-hidden'doesn't contain--emit-dwarf-unwindand--emulated-tls. When it is set totrue,rustc -C llvm-args='--help-list-hidden'emits--emit-dwarf-unwind, but--emulated-tlsis still missing.-Cllvm-args=--emit-dwarf-unwind=alwaysdoesn't take any effect, but-Cllvm-args=-machine-outliner-reruns=3does work.1
Adding
RegisterCodeGenFlagsto register codegen flags fixed the first problem.rustc -C llvm-args='--help-list-hidden'emits full codegen flags including--emit-dwarf-unwindand--emulated-tls.2
Constructing
TargetOptionsfromInitTargetOptionsFromCodeGenFlagsinLLVMRustCreateTargetMachinefixed the second problem. TheLLVMRustSetLLVMOptionscallsParseCommandLineOptionswhich parses givenllvm-args. For options likemachine-outliner-reruns, it just works, since the codegen logic directly consumes the parsing result:machine-outliner-reruns register
machine-outliner-reruns consumption
But for flags defined in
TargetOptionsandMCTargetOptionsto take effect, constructing them withInitTargetOptionsFromCodeGenFlagsis essential, or the parsing result is just not consumed. Similar patterns can be observed in lli, llc, etc.