rustc man page

rustc — The Rust compiler

TL;DR

rustc {{file.rs}}

rustc -O {{file.rs}}

rustc -g {{file.rs}}

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]
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|link|dep-info][=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]
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 <arch><sub>-<vendor>-<sys>-<abi>, where:

<arch>
x86, arm, thumb, mips, etc.
<sub>
for example on ARM: v5, v6m, v7a, v7m, etc.
<vendor>
pc, apple, nvidia, ibm, etc.
<sys>
none, linux, win32, darwin, cuda, etc.
<abi>
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.
--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 internal debugging 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

ar=/path/to/ar
Path to the archive utility to use when assembling archives.
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

Environment

Some of these affect the output of the compiler, while others affect programs which link to the 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/graph… or use `git log --all --format='%cN <%cE>' | sort -u` in the rust source distribution.

Referenced By

cargo(1), rustdoc(1).

September 2016 rustc 1.13.0 User Commands