diff --git a/src/doc/rustc/src/command-line-arguments.md b/src/doc/rustc/src/command-line-arguments.md index dfb40284ef6..bd7f6630ea2 100644 --- a/src/doc/rustc/src/command-line-arguments.md +++ b/src/doc/rustc/src/command-line-arguments.md @@ -17,28 +17,147 @@ to `#[cfg(verbose)]` and `#[cfg(feature = "serde")]` respectively. ## `-L`: add a directory to the library search path -When looking for external crates, a directory passed to this flag will be searched. +When looking for external crates or libraries, a directory passed to this flag +will be searched. + +The kind of search path can optionally be specified with the form `-L +KIND=PATH` where `KIND` may be one of: + +- `dependency` — Only search for transitive dependencies in this directory. +- `crate` — Only search for this crate's direct dependencies in this + directory. +- `native` — Only search for native libraries in this directory. +- `framework` — Only search for macOS frameworks in this directory. +- `all` — Search for all library kinds in this directory. This is the default + if `KIND` is not specified. ## `-l`: link the generated crate to a native library This flag allows you to specify linking to a specific native library when building a crate. +The kind of library can optionally be specified with the form `-l KIND=lib` +where `KIND` may be one of: + +- `dylib` — A native dynamic library. +- `static` — A native static library (such as a `.a` archive). +- `framework` — A macOS framework. + +The kind of library can be specified in a [`#[link]` +attribute][link-attribute]. If the kind is not specified in the `link` +attribute or on the command-line, it will link a dynamic library if available, +otherwise it will use a static library. If the kind is specified on the +command-line, it will override the kind specified in a `link` attribute. + +The name used in a `link` attribute may be overridden using the form `-l +ATTR_NAME:LINK_NAME` where `ATTR_NAME` is the name in the `link` attribute, +and `LINK_NAME` is the name of the actual library that will be linked. + +[link-attribute]: ../reference/items/external-blocks.html#the-link-attribute + ## `--crate-type`: a list of types of crates for the compiler to emit -This instructs `rustc` on which crate type to build. +This instructs `rustc` on which crate type to build. This flag accepts a +comma-separated list of values, and may be specified multiple times. The valid +crate types are: + +- `lib` — Generates a library kind preferred by the compiler, currently + defaults to `rlib`. +- `rlib` — A Rust static library. +- `staticlib` — A native static library. +- `dylib` — A Rust dynamic library. +- `cdylib` — A native dynamic library. +- `bin` — A runnable executable program. +- `proc-macro` — Generates a format suitable for a procedural macro library + that may be loaded by the compiler. + +The crate type may be specified with the [`crate_type` attribute][crate_type]. +The `--crate-type` command-line value will override the `crate_type` +attribute. + +More details may be found in the [linkage chapter] of the reference. + +[linkage chapter]: ../reference/linkage.html +[crate_type]: ../reference/linkage.html ## `--crate-name`: specify the name of the crate being built This informs `rustc` of the name of your crate. -## `--emit`: emit output other than a crate +## `--edition`: specify the edition to use -Instead of producing a crate, this flag can print out things like the assembly or LLVM-IR. +This flag takes a value of `2015` or `2018`. The default is `2015`. More +information about editions may be found in the [edition guide]. + +[edition guide]: ../edition-guide/introduction.html + +## `--emit`: specifies the types of output files to generate + +This flag controls the types of output files generated by the compiler. It +accepts a comma-separated list of values, and may be specified multiple times. +The valid emit kinds are: + +- `asm` — Generates a file with the crate's assembly code. The default output + filename is `CRATE_NAME.s`. +- `dep-info` — Generates a file with Makefile syntax that indicates all the + source files that were loaded to generate the crate. The default output + filename is `CRATE_NAME.d`. +- `link` — Generates the crates specified by `--crate-type`. The default + output filenames depend on the crate type and platform. This is the default + if `--emit` is not specified. +- `llvm-bc` — Generates a binary file containing the [LLVM bitcode]. The + default output filename is `CRATE_NAME.bc`. +- `llvm-ir` — Generates a file containing [LLVM IR]. The default output + filename is `CRATE_NAME.ll`. +- `metadata` — Generates a file containing metadata about the crate. The + default output filename is `CRATE_NAME.rmeta`. +- `mir` — Generates a file containing rustc's mid-level intermediate + representation. The default output filename is `CRATE_NAME.mir`. +- `obj` — Generates a native object file. The default output filename is + `CRATE_NAME.o`. + +The output filename can be set with the `-o` flag. A suffix may be added to +the filename with the `-C extra-filename` flag. The files are written to the +current directory unless the `--out-dir` flag is used. Each emission type may +also specify the output filename with the form `KIND=PATH`, which takes +precedence over the `-o` flag. + +[LLVM bitcode]: https://llvm.org/docs/BitCodeFormat.html +[LLVM IR]: https://llvm.org/docs/LangRef.html ## `--print`: print compiler information -This flag prints out various information about the compiler. +This flag prints out various information about the compiler. This flag may be +specified multiple times, and the information is printed in the order the +flags are specified. Specifying a `--print` flag will usually disable the +`--emit` step and will only print the requested information. The valid types +of print values are: + +- `crate-name` — The name of the crate. +- `file-names` — The names of the files created by the `link` emit kind. +- `sysroot` — Path to the sysroot. +- `cfg` — List of cfg values. See [conditional compilation] for more + information about cfg values. +- `target-list` — List of known targets. The target may be selected with the + `--target` flag. +- `target-cpus` — List of available CPU values for the current target. The + target CPU may be selected with the `-C target-cpu=val` flag. +- `target-features` — List of available target features for the current + target. Target features may be enabled with the `-C target-feature=val` + flag. +- `relocation-models` — List of relocation models. Relocation models may be + selected with the `-C relocation-model=val` flag. +- `code-models` — List of code models. Code models may be selected with the + `-C code-model=val` flag. +- `tls-models` — List of Thread Local Storage models supported. The model may + be selected with the `-Z tls-model=val` flag. +- `native-static-libs` — This may be used when creating a `staticlib` crate + type. If this is the only flag, it will perform a full compilation and + include a diagnostic note that indicates the linker flags to use when + linking the resulting static library. The note starts with the text + `native-static-libs:` to make it easier to fetch the output. + +[conditional compilation]: ../reference/conditional-compilation.html ## `-g`: include debug information @@ -54,7 +173,8 @@ This flag controls the output filename. ## `--out-dir`: directory to write the output in -The outputted crate will be written to this directory. +The outputted crate will be written to this directory. This flag is ignored if +the `-o` flag is used. ## `--explain`: provide a detailed explanation of an error message @@ -111,8 +231,9 @@ This flag, when combined with other flags, makes them produce extra output. ## `--extern`: specify where an external library is located -This flag allows you to pass the name and location of an external crate that will -be linked into the crate you're buildling. +This flag allows you to pass the name and location of an external crate that +will be linked into the crate you are building. This flag may be specified +multiple times. The format of the value should be `CRATENAME=PATH`. ## `--sysroot`: Override the system root @@ -121,8 +242,32 @@ distribution; this flag allows that to be overridden. ## `--error-format`: control how errors are produced -This flag lets you control the format of errors. +This flag lets you control the format of messages. Messages are printed to +stderr. The valid options are: + +- `human` — Human-readable output. This is the default. +- `json` — Structured JSON output. +- `short` — Short, one-line messages. ## `--color`: configure coloring of output -This flag lets you control color settings of the output. +This flag lets you control color settings of the output. The valid options +are: + +- `auto` — Use colors if output goes to a tty. This is the default. +- `always` — Always use colors. +- `never` — Never colorize output. + +## `--remap-path-prefix`: remap source names in output + +Remap source path prefixes in all output, including compiler diagnostics, +debug information, macro expansions, etc. It takes a value of the form +`FROM=TO` where a path prefix equal to `FROM` is rewritten to the value `TO`. +The `FROM` may itself contain an `=` symbol, but the `TO` value may not. This +flag may be specified multiple times. + +This is useful for normalizing build products, for example by removing the +current directory out of pathnames emitted into the object files. The +replacement is purely textual, with no consideration of the current system's +pathname syntax. For example `--remap-path-prefix foo=bar` will match +`foo/lib.rs` but not `./foo/lib.rs`. diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs index 12427daa383..b938ae504d8 100644 --- a/src/librustc/session/config.rs +++ b/src/librustc/session/config.rs @@ -1744,8 +1744,7 @@ pub fn rustc_short_optgroups() -> Vec { opt::multi_s( "", "print", - "Comma separated list of compiler information to \ - print on stdout", + "Compiler information to print on stdout", "[crate-name|file-names|sysroot|cfg|target-list|\ target-cpus|target-features|relocation-models|\ code-models|tls-models|target-spec-json|native-static-libs]",