src/bootstrap/config.toml.example - third_party/rust - Git at Google

 # Sample TOML configuration file for building Rust.
 #
 # All options are commented out by default in this file, and they're commented
 # out with their default values. The build system by default looks for
 # `config.toml` in the current directory of a build for build configuration, but
 # a custom configuration file can also be specified with `--config` to the build
 # system.

 # =============================================================================
 # Tweaking how LLVM is compiled
 # =============================================================================
 [llvm]

 # Indicates whether the LLVM build is a Release or Debug build
 #optimize = true

 # Indicates whether the LLVM assertions are enabled or not
 #assertions = false

 # Indicates whether ccache is used when building LLVM
 #ccache = false

 # If an external LLVM root is specified, we automatically check the version by
 # default to make sure it's within the range that we're expecting, but setting
 # this flag will indicate that this version check should not be done.
 #version-check = false

 # Link libstdc++ statically into the librustc_llvm instead of relying on a
 # dynamic version to be available.
 #static-libstdcpp = false

 # Tell the LLVM build system to use Ninja instead of the platform default for
 # the generated build system. This can sometimes be faster than make, for
 # example.
 #ninja = false

 # =============================================================================
 # General build configuration options
 # =============================================================================
 [build]

 # Build triple for the original snapshot compiler. This must be a compiler that
 # nightlies are already produced for. The current platform must be able to run
 # binaries of this build triple and the nightly will be used to bootstrap the
 # first compiler.
 #build = "x86_64-unknown-linux-gnu"    # defaults to your host platform

 # In addition to the build triple, other triples to produce full compiler
 # toolchains for. Each of these triples will be bootstrapped from the build
 # triple and then will continue to bootstrap themselves. This platform must
 # currently be able to run all of the triples provided here.
 #host = ["x86_64-unknown-linux-gnu"]   # defaults to just the build triple

 # In addition to all host triples, other triples to produce the standard library
 # for. Each host triple will be used to produce a copy of the standard library
 # for each target triple.
 #target = ["x86_64-unknown-linux-gnu"] # defaults to just the build triple

 # Instead of downloading the src/nightlies.txt version of Cargo specified, use
 # this Cargo binary instead to build all Rust code
 #cargo = "/path/to/bin/cargo"

 # Instead of downloading the src/nightlies.txt version of the compiler
 # specified, use this rustc binary instead as the stage0 snapshot compiler.
 #rustc = "/path/to/bin/rustc"

 # Flag to specify whether any documentation is built. If false, rustdoc and
 # friends will still be compiled but they will not be used to generate any
 # documentation.
 #docs = true

 # Indicate whether the compiler should be documented in addition to the standard
 # library and facade crates.
 #compiler-docs = false

 # =============================================================================
 # Options for compiling Rust code itself
 # =============================================================================
 [rust]

 # Whether or not to optimize the compiler and standard library
 #optimize = true

 # Number of codegen units to use for each compiler invocation. A value of 0
 # means "the number of cores on this machine", and 1+ is passed through to the
 # compiler.
 #codegen-units = 1

 # Whether or not debug assertions are enabled for the compiler and standard
 # library
 #debug-assertions = false

 # Whether or not debuginfo is emitted
 #debuginfo = false

 # Whether or not jemalloc is built and enabled
 #use-jemalloc = true

 # Whether or not jemalloc is built with its debug option set
 #debug-jemalloc = false

 # The default linker that will be used by the generated compiler. Note that this
 # is not the linker used to link said compiler.
 #default-linker = "cc"

 # The default ar utility that will be used by the generated compiler if LLVM
 # cannot be used. Note that this is not used to assemble said compiler.
 #default-ar = "ar"

 # The "channel" for the Rust build to produce. The stable/beta channels only
 # allow using stable features, whereas the nightly and dev channels allow using
 # nightly features
 #channel = "dev"

 # The root location of the MUSL installation directory. The library directory
 # will also need to contain libunwind.a for an unwinding implementation.
 #musl-root = "..."

 # By default the `rustc` executable is built with `-Wl,-rpath` flags on Unix
 # platforms to ensure that the compiler is usable by default from the build
 # directory (as it links to a number of dynamic libraries). This may not be
 # desired in distributions, for example.
 #rpath = true

 # Flag indicating whether tests are compiled with optimizations (the -O flag) or
 # with debuginfo (the -g flag)
 #optimize-tests = true
 #debuginfo-tests = true

 # =============================================================================
 # Options for specific targets
 #
 # Each of the following options is scoped to the specific target triple in
 # question and is used for determining how to compile each target.
 # =============================================================================
 [target.x86_64-unknown-linux-gnu]

 # C compiler to be used to compiler C code and link Rust code. Note that the
 # default value is platform specific, and if not specified it may also depend on
 # what platform is crossing to what platform.
 #cc = "cc"

 # C++ compiler to be used to compiler C++ code (e.g. LLVM and our LLVM shims).
 # This is only used for host targets.
 #cxx = "c++"

 # Path to the `llvm-config` binary of the installation of a custom LLVM to link
 # against. Note that if this is specifed we don't compile LLVM at all for this
 # target.
 #llvm-config = "../path/to/llvm/root/bin/llvm-config"

 # Path to the custom jemalloc static library to link into the standard library
 # by default. This is only used if jemalloc is still enabled above
 #jemalloc = "/path/to/jemalloc/libjemalloc_pic.a"

 # If this target is for Android, this option will be required to specify where
 # the NDK for the target lives. This is used to find the C compiler to link and
 # build native code.
 #android-ndk = "/path/to/ndk"
	# Sample TOML configuration file for building Rust.
	#
	# All options are commented out by default in this file, and they're commented
	# out with their default values. The build system by default looks for
	# `config.toml` in the current directory of a build for build configuration, but
	# a custom configuration file can also be specified with `--config` to the build
	# system.

	# =============================================================================
	# Tweaking how LLVM is compiled
	# =============================================================================
	[llvm]

	# Indicates whether the LLVM build is a Release or Debug build
	#optimize = true

	# Indicates whether the LLVM assertions are enabled or not
	#assertions = false

	# Indicates whether ccache is used when building LLVM
	#ccache = false

	# If an external LLVM root is specified, we automatically check the version by
	# default to make sure it's within the range that we're expecting, but setting
	# this flag will indicate that this version check should not be done.
	#version-check = false

	# Link libstdc++ statically into the librustc_llvm instead of relying on a
	# dynamic version to be available.
	#static-libstdcpp = false

	# Tell the LLVM build system to use Ninja instead of the platform default for
	# the generated build system. This can sometimes be faster than make, for
	# example.
	#ninja = false

	# =============================================================================
	# General build configuration options
	# =============================================================================
	[build]

	# Build triple for the original snapshot compiler. This must be a compiler that
	# nightlies are already produced for. The current platform must be able to run
	# binaries of this build triple and the nightly will be used to bootstrap the
	# first compiler.
	#build = "x86_64-unknown-linux-gnu" # defaults to your host platform

	# In addition to the build triple, other triples to produce full compiler
	# toolchains for. Each of these triples will be bootstrapped from the build
	# triple and then will continue to bootstrap themselves. This platform must
	# currently be able to run all of the triples provided here.
	#host = ["x86_64-unknown-linux-gnu"] # defaults to just the build triple

	# In addition to all host triples, other triples to produce the standard library
	# for. Each host triple will be used to produce a copy of the standard library
	# for each target triple.
	#target = ["x86_64-unknown-linux-gnu"] # defaults to just the build triple

	# Instead of downloading the src/nightlies.txt version of Cargo specified, use
	# this Cargo binary instead to build all Rust code
	#cargo = "/path/to/bin/cargo"

	# Instead of downloading the src/nightlies.txt version of the compiler
	# specified, use this rustc binary instead as the stage0 snapshot compiler.
	#rustc = "/path/to/bin/rustc"

	# Flag to specify whether any documentation is built. If false, rustdoc and
	# friends will still be compiled but they will not be used to generate any
	# documentation.
	#docs = true

	# Indicate whether the compiler should be documented in addition to the standard
	# library and facade crates.
	#compiler-docs = false

	# =============================================================================
	# Options for compiling Rust code itself
	# =============================================================================
	[rust]

	# Whether or not to optimize the compiler and standard library
	#optimize = true

	# Number of codegen units to use for each compiler invocation. A value of 0
	# means "the number of cores on this machine", and 1+ is passed through to the
	# compiler.
	#codegen-units = 1

	# Whether or not debug assertions are enabled for the compiler and standard
	# library
	#debug-assertions = false

	# Whether or not debuginfo is emitted
	#debuginfo = false

	# Whether or not jemalloc is built and enabled
	#use-jemalloc = true

	# Whether or not jemalloc is built with its debug option set
	#debug-jemalloc = false

	# The default linker that will be used by the generated compiler. Note that this
	# is not the linker used to link said compiler.
	#default-linker = "cc"

	# The default ar utility that will be used by the generated compiler if LLVM
	# cannot be used. Note that this is not used to assemble said compiler.
	#default-ar = "ar"

	# The "channel" for the Rust build to produce. The stable/beta channels only
	# allow using stable features, whereas the nightly and dev channels allow using
	# nightly features
	#channel = "dev"

	# The root location of the MUSL installation directory. The library directory
	# will also need to contain libunwind.a for an unwinding implementation.
	#musl-root = "..."

	# By default the `rustc` executable is built with `-Wl,-rpath` flags on Unix
	# platforms to ensure that the compiler is usable by default from the build
	# directory (as it links to a number of dynamic libraries). This may not be
	# desired in distributions, for example.
	#rpath = true

	# Flag indicating whether tests are compiled with optimizations (the -O flag) or
	# with debuginfo (the -g flag)
	#optimize-tests = true
	#debuginfo-tests = true

	# =============================================================================
	# Options for specific targets
	#
	# Each of the following options is scoped to the specific target triple in
	# question and is used for determining how to compile each target.
	# =============================================================================
	[target.x86_64-unknown-linux-gnu]

	# C compiler to be used to compiler C code and link Rust code. Note that the
	# default value is platform specific, and if not specified it may also depend on
	# what platform is crossing to what platform.
	#cc = "cc"

	# C++ compiler to be used to compiler C++ code (e.g. LLVM and our LLVM shims).
	# This is only used for host targets.
	#cxx = "c++"

	# Path to the `llvm-config` binary of the installation of a custom LLVM to link
	# against. Note that if this is specifed we don't compile LLVM at all for this
	# target.
	#llvm-config = "../path/to/llvm/root/bin/llvm-config"

	# Path to the custom jemalloc static library to link into the standard library
	# by default. This is only used if jemalloc is still enabled above
	#jemalloc = "/path/to/jemalloc/libjemalloc_pic.a"

	# If this target is for Android, this option will be required to specify where
	# the NDK for the target lives. This is used to find the C compiler to link and
	# build native code.
	#android-ndk = "/path/to/ndk"