rust/mk/target.mk
Alex Crichton 02538d463a mk: Bootstrap from stable instead of snapshots
This commit removes all infrastructure from the repository for our so-called
snapshots to instead bootstrap the compiler from stable releases. Bootstrapping
from a previously stable release is a long-desired feature of distros because
they're not fans of downloading binary stage0 blobs from us. Additionally, this
makes our own CI easier as we can decommission all of the snapshot builders and
start having a regular cadence to when we update the stage0 compiler.

A new `src/etc/get-stage0.py` script was added which shares some code with
`src/bootstrap/bootstrap.py` to read a new file, `src/stage0.txt`, which lists
the current stage0 compiler as well as cargo that we bootstrap from. This script
will download the relevant `rustc` package an unpack it into `$target/stage0` as
we do today.

One problem of bootstrapping from stable releases is that we're not able to
compile unstable code (e.g. all the `#![feature]` directives in libcore/libstd).
To overcome this we employ two strategies:

* The bootstrap key of the previous compiler is hardcoded into `src/stage0.txt`
  (enabled as a result of ) and exported by the build system. This enables
  nightly features in the compiler we download.
* The standard library and compiler are pinned to a specific stage0, which
  doesn't change, so we're guaranteed that we'll continue compiling as we start
  from a known fixed source.

The process for making a release will also need to be tweaked now to continue to
cadence of bootstrapping from the previous release. This process looks like:

1. Merge `beta` to `stable`
2. Produce a new stable compiler.
3. Change `master` to bootstrap from this new stable compiler.
4. Merge `master` to `beta`
5. Produce a new beta compiler
6. Change `master` to bootstrap from this new beta compiler.

Step 3 above should involve very few changes as `master` was previously
bootstrapping from `beta` which is the same as `stable` at that point in time.
Step 6, however, is where we benefit from removing lots of `#[cfg(stage0)]` and
get to use new features. This also shouldn't slow the release too much as steps
1-5 requires little work other than waiting and step 6 just needs to happen at
some point during a release cycle, it's not time sensitive.

Closes 
Closes 
2016-04-19 10:56:49 -07:00

220 lines
7.9 KiB
Makefile

# Copyright 2012 The Rust Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution and at
# http://rust-lang.org/COPYRIGHT.
#
# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
# option. This file may not be copied, modified, or distributed
# except according to those terms.
# This is the compile-time target-triple for the compiler. For the compiler at
# runtime, this should be considered the host-triple. More explanation for why
# this exists can be found on issue #2400
export CFG_COMPILER_HOST_TRIPLE
# Used as defaults for the runtime ar and cc tools
export CFG_DEFAULT_LINKER
export CFG_DEFAULT_AR
# Macro that generates the full list of dependencies for a crate at a particular
# stage/target/host tuple.
#
# $(1) - stage
# $(2) - target
# $(3) - host
# $(4) crate
define RUST_CRATE_FULLDEPS
CRATE_FULLDEPS_$(1)_T_$(2)_H_$(3)_$(4) := \
$$(CRATEFILE_$(4)) \
$$(RSINPUTS_$(4)) \
$$(foreach dep,$$(RUST_DEPS_$(4)_T_$(2)), \
$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$$(dep)) \
$$(foreach dep,$$(NATIVE_DEPS_$(4)), \
$$(RT_OUTPUT_DIR_$(2))/$$(call CFG_STATIC_LIB_NAME_$(2),$$(dep))) \
$$(foreach dep,$$(NATIVE_DEPS_$(4)_T_$(2)), \
$$(RT_OUTPUT_DIR_$(2))/$$(dep))
endef
$(foreach host,$(CFG_HOST), \
$(foreach target,$(CFG_TARGET), \
$(foreach stage,$(STAGES), \
$(foreach crate,$(CRATES), \
$(eval $(call RUST_CRATE_FULLDEPS,$(stage),$(target),$(host),$(crate)))))))
# RUST_TARGET_STAGE_N template: This defines how target artifacts are built
# for all stage/target architecture combinations. This is one giant rule which
# works as follows:
#
# 1. The immediate dependencies are the rust source files
# 2. Each rust crate dependency is listed (based on their stamp files),
# as well as all native dependencies (listed in RT_OUTPUT_DIR)
# 3. The stage (n-1) compiler is required through the TSREQ dependency
# 4. When actually executing the rule, the first thing we do is to clean out
# old libs and rlibs via the REMOVE_ALL_OLD_GLOB_MATCHES macro
# 5. Finally, we get around to building the actual crate. It's just one
# "small" invocation of the previous stage rustc. We use -L to
# RT_OUTPUT_DIR so all the native dependencies are picked up.
# Additionally, we pass in the llvm dir so rustc can link against it.
# 6. Some cleanup is done (listing what was just built) if verbose is turned
# on.
#
# $(1) is the stage
# $(2) is the target triple
# $(3) is the host triple
# $(4) is the crate name
define RUST_TARGET_STAGE_N
ifeq ($(1),0)
$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$(4): \
export RUSTC_BOOTSTRAP_KEY := $$(CFG_BOOTSTRAP_KEY_STAGE0)
endif
$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$(4): CFG_COMPILER_HOST_TRIPLE = $(2)
$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$(4): \
$$(CRATEFILE_$(4)) \
$$(CRATE_FULLDEPS_$(1)_T_$(2)_H_$(3)_$(4)) \
$$(LLVM_CONFIG_$(2)) \
$$(TSREQ$(1)_T_$(2)_H_$(3)) \
| $$(TLIB$(1)_T_$(2)_H_$(3))/
@$$(call E, rustc: $$(@D)/lib$(4))
@touch $$@.start_time
$$(call REMOVE_ALL_OLD_GLOB_MATCHES, \
$$(dir $$@)$$(call CFG_LIB_GLOB_$(2),$(4)))
$$(call REMOVE_ALL_OLD_GLOB_MATCHES, \
$$(dir $$@)$$(call CFG_RLIB_GLOB,$(4)))
$(Q)CFG_LLVM_LINKAGE_FILE=$$(LLVM_LINKAGE_PATH_$(2)) \
$$(subst @,,$$(STAGE$(1)_T_$(2)_H_$(3))) \
$$(RUST_LIB_FLAGS_ST$(1)) \
-L "$$(RT_OUTPUT_DIR_$(2))" \
$$(LLVM_LIBDIR_RUSTFLAGS_$(2)) \
$$(LLVM_STDCPP_RUSTFLAGS_$(2)) \
$$(RUSTFLAGS_$(4)) \
$$(RUSTFLAGS$(1)_$(4)) \
$$(RUSTFLAGS$(1)_$(4)_T_$(2)) \
--out-dir $$(@D) \
-C extra-filename=-$$(CFG_FILENAME_EXTRA) \
-C metadata=$$(CFG_FILENAME_EXTRA) \
$$<
@touch -r $$@.start_time $$@ && rm $$@.start_time
$$(call LIST_ALL_OLD_GLOB_MATCHES, \
$$(dir $$@)$$(call CFG_LIB_GLOB_$(2),$(4)))
$$(call LIST_ALL_OLD_GLOB_MATCHES, \
$$(dir $$@)$$(call CFG_RLIB_GLOB,$(4)))
endef
# Macro for building any tool as part of the rust compilation process. Each
# tool is defined in crates.mk with a list of library dependencies as well as
# the source file for the tool. Building each tool will also be passed '--cfg
# <tool>' for usage in driver.rs
#
# This build rule is similar to the one found above, just tweaked for
# locations and things.
#
# $(1) - stage
# $(2) - target triple
# $(3) - host triple
# $(4) - name of the tool being built
define TARGET_TOOL
ifeq ($(1),0)
$$(TBIN$(1)_T_$(2)_H_$(3))/$(4)$$(X_$(2)): \
export RUSTC_BOOTSTRAP_KEY := $$(CFG_BOOTSTRAP_KEY_STAGE0)
endif
$$(TBIN$(1)_T_$(2)_H_$(3))/$(4)$$(X_$(2)): \
$$(TOOL_SOURCE_$(4)) \
$$(TOOL_INPUTS_$(4)) \
$$(foreach dep,$$(TOOL_DEPS_$(4)), \
$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$$(dep)) \
$$(TSREQ$(1)_T_$(2)_H_$(3)) \
| $$(TBIN$(1)_T_$(2)_H_$(3))/
@$$(call E, rustc: $$@)
$$(STAGE$(1)_T_$(2)_H_$(3)) \
$$(LLVM_LIBDIR_RUSTFLAGS_$(2)) \
-o $$@ $$< --cfg $(4)
endef
# Macro for building runtime startup/shutdown object files;
# these are Rust's equivalent of crti.o, crtn.o
#
# $(1) - stage
# $(2) - target triple
# $(3) - host triple
# $(4) - object basename
define TARGET_RUSTRT_STARTUP_OBJ
$$(TLIB$(1)_T_$(2)_H_$(3))/$(4).o: \
$(S)src/rtstartup/$(4).rs \
$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.core \
$$(HSREQ$(1)_T_$(2)_H_$(3)) \
| $$(TBIN$(1)_T_$(2)_H_$(3))/
@$$(call E, rustc: $$@)
$$(STAGE$(1)_T_$(2)_H_$(3)) --emit=obj -o $$@ $$<
ifeq ($$(CFG_RUSTRT_HAS_STARTUP_OBJS_$(2)), 1)
# Add dependencies on Rust startup objects to all crates that depend on core.
# This ensures that they are built after core (since they depend on it),
# but before everything else (since they are needed for linking dylib crates).
$$(foreach crate, $$(TARGET_CRATES_$(2)), \
$$(if $$(findstring core,$$(DEPS_$$(crate))), \
$$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$$(crate))) : $$(TLIB$(1)_T_$(2)_H_$(3))/$(4).o
endif
endef
# Every recipe in RUST_TARGET_STAGE_N outputs to $$(TLIB$(1)_T_$(2)_H_$(3),
# a directory that can be cleaned out during the middle of a run of
# the get-snapshot.py script. Therefore, every recipe needs to have
# an order-only dependency either on $(SNAPSHOT_RUSTC_POST_CLEANUP) or
# on $$(TSREQ$(1)_T_$(2)_H_$(3)), to ensure that no products will be
# put into the target area until after the get-snapshot.py script has
# had its chance to clean it out; otherwise the other products will be
# inadvertently included in the clean out.
SNAPSHOT_RUSTC_POST_CLEANUP=$(HBIN0_H_$(CFG_BUILD))/rustc$(X_$(CFG_BUILD))
define TARGET_HOST_RULES
$$(TLIB$(1)_T_$(2)_H_$(3))/: $$(SNAPSHOT_RUSTC_POST_CLEANUP)
mkdir -p $$@
$$(TBIN$(1)_T_$(2)_H_$(3))/: $$(SNAPSHOT_RUSTC_POST_CLEANUP)
mkdir -p $$@
$$(TLIB$(1)_T_$(2)_H_$(3))/%: $$(RT_OUTPUT_DIR_$(2))/% \
$$(SNAPSHOT_RUSTC_POST_CLEANUP) \
| $$(TLIB$(1)_T_$(2)_H_$(3))/
@$$(call E, cp: $$@)
$$(Q)cp $$< $$@
endef
$(foreach source,$(CFG_HOST), \
$(foreach target,$(CFG_TARGET), \
$(eval $(call TARGET_HOST_RULES,0,$(target),$(source))) \
$(eval $(call TARGET_HOST_RULES,1,$(target),$(source))) \
$(eval $(call TARGET_HOST_RULES,2,$(target),$(source))) \
$(eval $(call TARGET_HOST_RULES,3,$(target),$(source)))))
# In principle, each host can build each target for both libs and tools
$(foreach crate,$(CRATES), \
$(foreach source,$(CFG_HOST), \
$(foreach target,$(CFG_TARGET), \
$(eval $(call RUST_TARGET_STAGE_N,0,$(target),$(source),$(crate))) \
$(eval $(call RUST_TARGET_STAGE_N,1,$(target),$(source),$(crate))) \
$(eval $(call RUST_TARGET_STAGE_N,2,$(target),$(source),$(crate))) \
$(eval $(call RUST_TARGET_STAGE_N,3,$(target),$(source),$(crate))))))
$(foreach host,$(CFG_HOST), \
$(foreach target,$(CFG_TARGET), \
$(foreach stage,$(STAGES), \
$(foreach tool,$(TOOLS), \
$(eval $(call TARGET_TOOL,$(stage),$(target),$(host),$(tool)))))))
$(foreach host,$(CFG_HOST), \
$(foreach target,$(CFG_TARGET), \
$(foreach stage,$(STAGES), \
$(foreach obj,rsbegin rsend, \
$(eval $(call TARGET_RUSTRT_STARTUP_OBJ,$(stage),$(target),$(host),$(obj)))))))