rustc: Improve the dep-info experience #28768
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Currently the compiler supports the ability to emit multiple output types as part of one compilation (e.g. asm, LLVM IR, bytecode, link, dep-info, etc). It does not, however, support the ability to customize the output filename for each of these output types. The `-o` flag is ignored if multiple emit types are specified (and the compiler emits a warning about this). Normally this doesn't matter too much, but in the case of `dep-info` it can lead to a number of problems (e.g. see rust-lang#28716). By allowing customization of the output filename for each emit type we're able to solve the problems in that issue. This commit adds support for the `--emit` option to the compiler to look like: rustc foo.rs --emit dep-info=.deps/foo.d,link This indicates that the `dep-info` output type will be placed at `.deps/foo.d` and the `link` output type will otherwise be determined via the `--out-dir` and `-o` flags. Closes rust-lang#28716
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r? @brson cc @rust-lang/tools -- changes to CLI flags here. |
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r? @Aatch (rust_highfive has picked a reviewer for you, use r? to override) |
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cc @froydnj @rillian @apasel422 Hopefully a gecko engineer will give this a look. |
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r=me when you decide the phony issue and one of the gecko devs checks in. |
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Whether the targets are 'phony' in the make-specific sense depends on whether the file is present or not. 'dummy target' might be a better term. In any case, we don't want these included in a .PHONY tells make to always run the rule for the specified targets, whether a file with the name of that target is present or not. This avoids files shadowing invocation targets like 'clean' or 'doc' which are intended to never be considered up-to-date, which is not the case we have here. gcc doesn't emit any .PHONY rules either. |
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The GCC documentation calls them "phony" targets, which, as @rillian pointed out, has nothing to do with |
This helps protect against files being deleted to ensure that `make` won't emit errors. Closes rust-lang#28735
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This PR closes out #28716 and #28735 by making two changes to the compiler: 1. The `--emit` flag to the compiler now supports the ability to specify the output file name of a partuclar emit type. For example `--emit dep-info=bar.d,asm=foo.s,link` is now accepted. 2. The dep-info emission now emits a dummy target for all input file names to protect against deleted files.
This PR closes out #28716 and #28735 by making two changes to the compiler:
--emitflag to the compiler now supports the ability to specify the output file name of a partuclar emit type. For example--emit dep-info=bar.d,asm=foo.s,linkis now accepted.