RUSTC(1) User Commands RUSTC(1) NAME rustc - The Rust compiler SYNOPSIS rustc [OPTIONS] INPUT DESCRIPTION This program is a compiler for the Rust language, available at https://www.rust-lang.org. OPTIONS -h, --help Display the help message. --cfg SPEC Configure the compilation environment. -L [KIND=]PATH Add a directory to the library search path. The optional KIND can be one of: dependency only lookup transitive dependencies here crate only lookup local `extern crate` directives here native only lookup native libraries here framework only look for OSX frameworks here all look for anything here (the default) -l [KIND=]NAME Link the generated crate(s) to the specified library NAME. The optional KIND can be one of static, dylib, or framework. If omitted, dylib is assumed. --crate-type [bin|lib|rlib|dylib|cdylib|staticlib|proc-macro] Comma separated list of types of crates for the compiler to emit. --crate-name NAME Specify the name of the crate being built. --emit [asm|llvm-bc|llvm-ir|obj|metadata|link|dep-info|mir][=PATH] Configure the output that rustc will produce. Each emission may also have an optional explicit output PATH specified for that particular emission kind. This path takes precedence over the -o option. --print [crate-name|file-names|sysroot|target-libdir|cfg|target-list| target-cpus|target-features|relocation-models|code-models|tls-models| target-spec-json|native-static-libs|stack-protector-strategies| link-args] Comma separated list of compiler information to print on stdout. -g Equivalent to -C debuginfo=2. -O Equivalent to -C opt-level=2. -o FILENAME Write output to FILENAME. Ignored if multiple --emit outputs are specified which don't have an explicit path otherwise. --out-dir DIR Write output to compiler-chosen filename in DIR. Ignored if -o is specified. Defaults to the current directory. --explain OPT Provide a detailed explanation of an error message. --test Build a test harness. --target TARGET Target triple for which the code is compiled. This option defaults to the host's target triple. The target triple has the general format ---, where: x86, arm, thumb, mips, etc. for example on ARM: v5, v6m, v7a, v7m, etc. pc, apple, nvidia, ibm, etc. none, linux, win32, darwin, cuda, etc. eabi, gnu, android, macho, elf, etc. -W help Print 'lint' options and default settings. -W OPT, --warn OPT Set lint warnings. -A OPT, --allow OPT Set lint allowed. -D OPT, --deny OPT Set lint denied. -F OPT, --forbid OPT Set lint forbidden. -C FLAG[=VAL], --codegen FLAG[=VAL] Set a codegen-related flag to the value specified. Use -C help to print available flags. See CODEGEN OPTIONS below. -V, --version Print version info and exit. -v, --verbose Use verbose output. --remap-path-prefix from=to Remap source path prefixes in all output, including compiler diagnostics, debug information, macro expansions, etc. The from=to parameter is scanned from right to left, so from may contain '=', but to may not. 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. --extern NAME=PATH Specify where an external rust library is located. These should match extern declarations in the crate's source code. --sysroot PATH Override the system root. -Z FLAG Set unstable / perma-unstable options. Use -Z help to print available options. --color auto|always|never Configure coloring of output: auto colorize, if output goes to a tty (default); always always colorize output; never never colorize output. CODEGEN OPTIONS linker=/path/to/cc Path to the linker utility to use when linking libraries, executables, and objects. link-args='-flag1 -flag2' A space-separated list of extra arguments to pass to the linker when the linker is invoked. lto Perform LLVM link-time optimizations. target-cpu=help Selects a target processor. If the value is 'help', then a list of available CPUs is printed. target-feature='+feature1,-feature2' A comma-separated list of features to enable or disable for the target. A preceding '+' enables a feature while a preceding '-' disables it. Available features can be discovered through llc -mcpu=help. passes=val A space-separated list of extra LLVM passes to run. A value of 'list' will cause rustc to print all known passes and exit. The passes specified are appended at the end of the normal pass manager. llvm-args='-arg1 -arg2' A space-separated list of arguments to pass through to LLVM. save-temps If specified, the compiler will save more files (.bc, .o, .no-opt.bc) generated throughout compilation in the output directory. rpath If specified, then the rpath value for dynamic libraries will be set in either dynamic library or executable outputs. no-prepopulate-passes Suppresses pre-population of the LLVM pass manager that is run over the module. no-vectorize-loops Suppresses running the loop vectorization LLVM pass, regardless of optimization level. no-vectorize-slp Suppresses running the LLVM SLP vectorization pass, regardless of optimization level. soft-float Generates software floating point library calls instead of hardware instructions. prefer-dynamic Prefers dynamic linking to static linking. no-integrated-as Force usage of an external assembler rather than LLVM's integrated one. no-redzone Disable the use of the redzone. relocation-model=[pic,static,dynamic-no-pic] The relocation model to use. (Default: pic) code-model=[small,kernel,medium,large] Choose the code model to use. metadata=val Metadata to mangle symbol names with. extra-filename=val Extra data to put in each output filename. codegen-units=n Divide crate into n units to optimize in parallel. remark=val Print remarks for these optimization passes (space separated, or "all"). no-stack-check Disable checks for stack exhaustion (a memory-safety hazard!). debuginfo=val Debug info emission level: 0 no debug info; 1 line-tables only (for stacktraces and breakpoints); 2 full debug info with variable and type information. opt-level=VAL Optimize with possible levels 0-3, s (optimize for size), or z (for minimal size) ENVIRONMENT Some of these affect only test harness programs (generated via rustc --test); others affect all programs which link to the Rust standard library. RUST_TEST_THREADS The test framework Rust provides executes tests in parallel. This variable sets the maximum number of threads used for this purpose. This setting is overridden by the --test-threads option. RUST_TEST_NOCAPTURE If set to a value other than "0", a synonym for the --nocapture flag. RUST_MIN_STACK Sets the minimum stack size for new threads. RUST_BACKTRACE If set to a value different than "0", produces a backtrace in the output of a program which panics. EXAMPLES To build an executable from a source file with a main function: $ rustc -o hello hello.rs To build a library from a source file: $ rustc --crate-type=lib hello-lib.rs To build either with a crate (.rs) file: $ rustc hello.rs To build an executable with debug info: $ rustc -g -o hello hello.rs SEE ALSO rustdoc(1) BUGS See https://github.com/rust-lang/rust/issues for issues. AUTHOR See https://github.com/rust-lang/rust/graphs/contributors or use `git log --all --format='%cN <%cE>' | sort -u` in the rust source distribution. COPYRIGHT This work is dual-licensed under Apache 2.0 and MIT terms. See COPYRIGHT file in the rust source distribution. rustc April 2019 RUSTC(1)