kbuild: mark `rustc` (and others) invocations as recursive

`rustc` (like Cargo) may take advantage of the jobserver at any time (e.g. for backend parallelism, or eventually frontend too). In the kernel, we call `rustc` with `-Ccodegen-units=1` (and `-Zthreads` is 1 so far), so we do not expect parallelism. However, in the upcoming Rust 1.76.0, a warning is emitted by `rustc` [1] when it cannot connect to the jobserver it was passed (in many cases, but not all: compiling and `--print sysroot` do, but `--version` does not). And given GNU Make always passes the jobserver in the environment variable (even when a line is deemed non-recursive), `rustc` will end up complaining about it (in particular in Make 4.3 where there is only the simple pipe jobserver style). One solution is to remove the jobserver from `MAKEFLAGS`. However, we can mark the lines with calls to `rustc` (and Cargo) as recursive, which looks simpler. This is being documented as a recommendation in `rustc` [2] and allows us to be ready for the time we may use parallelism inside `rustc` (potentially now, if a user passes `-Zthreads`). Thus do so. Similarly, do the same for `rustdoc` and `cargo` calls. Finally, there is one case that the solution does not cover, which is the `$(shell ...)` call we have. Thus, for that one, set an empty `MAKEFLAGS` environment variable.

Miguel Ojeda committed 2 years ago

Commit ecab4111 parent e9441714 files · +31 −31Browse files

Unified · Split

4 files

Makefile +2 −2
rust/Makefile +24 −24
scripts/Makefile.build +4 −4
scripts/Makefile.host +1 −1

Makefile+2−2

@@ -1197,7 +1197,7 @@ prepare0: archprepare · 1196 unmodified lines
1197	# All the preparing..	1197	# All the preparing..
1198	prepare: prepare0	1198	prepare: prepare0
1199	ifdef CONFIG_RUST	1199	ifdef CONFIG_RUST
1200	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh	1200	+$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh
1201	$(Q)$(MAKE) $(build)=rust	1201	$(Q)$(MAKE) $(build)=rust
1202	endif	1202	endif
1203		1203
@@ -1707,7 +1707,7 @@ $(DOC_TARGETS): · 503 unmodified lines
1707	# "Is Rust available?" target	1707	# "Is Rust available?" target
1708	PHONY += rustavailable	1708	PHONY += rustavailable
1709	rustavailable:	1709	rustavailable:
1710	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh && echo "Rust is available!"	1710	+$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh && echo "Rust is available!"
1711		1711
1712	# Documentation target	1712	# Documentation target
1713	#	1713	#

rust/Makefile+24−24

scripts/Makefile.build+4−4

scripts/Makefile.host+1−1

@@ -156,7 +156,7 @@ quiet_cmd_host-rust = HOSTRUSTC $@ · 155 unmodified lines
156	cmd_host-rust = \	156	cmd_host-rust = \
157	$(HOSTRUSTC) $(hostrust_flags) --emit=link=$@ $<	157	$(HOSTRUSTC) $(hostrust_flags) --emit=link=$@ $<
158	$(host-rust): $(obj)/%: $(src)/%.rs FORCE	158	$(host-rust): $(obj)/%: $(src)/%.rs FORCE
159	$(call if_changed_dep,host-rust)	159	+$(call if_changed_dep,host-rust)
160		160
161	targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \	161	targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \
162	$(host-cxxmulti) $(host-cxxobjs) $(host-rust)	162	$(host-cxxmulti) $(host-cxxobjs) $(host-rust)

@@ -40,7 +40,7 @@ obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.o · 39 unmodified lines
40	ifdef CONFIG_RUST	40	ifdef CONFIG_RUST
41		41
42	# `$(rust_flags)` is passed in case the user added `--sysroot`.	42	# `$(rust_flags)` is passed in case the user added `--sysroot`.
43	rustc_sysroot := $(shell $(RUSTC) $(rust_flags) --print sysroot)	43	rustc_sysroot := $(shell MAKEFLAGS= $(RUSTC) $(rust_flags) --print sysroot)
44	rustc_host_target := $(shell $(RUSTC) --version --verbose \| grep -F 'host: ' \| cut -d' ' -f2)	44	rustc_host_target := $(shell $(RUSTC) --version --verbose \| grep -F 'host: ' \| cut -d' ' -f2)
45	RUST_LIB_SRC ?= $(rustc_sysroot)/lib/rustlib/src/rust/library	45	RUST_LIB_SRC ?= $(rustc_sysroot)/lib/rustlib/src/rust/library
46		46
@@ -108,14 +108,14 @@ rustdoc-macros: private rustdoc_host = yes · 61 unmodified lines
108	rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \	108	rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \
109	--extern proc_macro	109	--extern proc_macro
110	rustdoc-macros: $(src)/macros/lib.rs FORCE	110	rustdoc-macros: $(src)/macros/lib.rs FORCE
111	$(call if_changed,rustdoc)	111	+$(call if_changed,rustdoc)
112		112
113	rustdoc-core: private rustc_target_flags = $(core-cfgs)	113	rustdoc-core: private rustc_target_flags = $(core-cfgs)
114	rustdoc-core: $(RUST_LIB_SRC)/core/src/lib.rs FORCE	114	rustdoc-core: $(RUST_LIB_SRC)/core/src/lib.rs FORCE
115	$(call if_changed,rustdoc)	115	+$(call if_changed,rustdoc)
116		116
117	rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE	117	rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE
118	$(call if_changed,rustdoc)	118	+$(call if_changed,rustdoc)
119		119
120	# We need to allow `rustdoc::broken_intra_doc_links` because some	120	# We need to allow `rustdoc::broken_intra_doc_links` because some
121	# `no_global_oom_handling` functions refer to non-`no_global_oom_handling`	121	# `no_global_oom_handling` functions refer to non-`no_global_oom_handling`
@@ -124,7 +124,7 @@ rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE · 2 unmodified lines
124	rustdoc-alloc: private rustc_target_flags = $(alloc-cfgs) \	124	rustdoc-alloc: private rustc_target_flags = $(alloc-cfgs) \
125	-Arustdoc::broken_intra_doc_links	125	-Arustdoc::broken_intra_doc_links
126	rustdoc-alloc: $(src)/alloc/lib.rs rustdoc-core rustdoc-compiler_builtins FORCE	126	rustdoc-alloc: $(src)/alloc/lib.rs rustdoc-core rustdoc-compiler_builtins FORCE
127	$(call if_changed,rustdoc)	127	+$(call if_changed,rustdoc)
128		128
129	rustdoc-kernel: private rustc_target_flags = --extern alloc \	129	rustdoc-kernel: private rustc_target_flags = --extern alloc \
130	--extern build_error --extern macros=$(objtree)/$(obj)/libmacros.so \	130	--extern build_error --extern macros=$(objtree)/$(obj)/libmacros.so \
@@ -132,7 +132,7 @@ rustdoc-kernel: private rustc_target_flags = --extern alloc \ · 1 unmodified line
132	rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \	132	rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \
133	rustdoc-compiler_builtins rustdoc-alloc $(obj)/libmacros.so \	133	rustdoc-compiler_builtins rustdoc-alloc $(obj)/libmacros.so \
134	$(obj)/bindings.o FORCE	134	$(obj)/bindings.o FORCE
135	$(call if_changed,rustdoc)	135	+$(call if_changed,rustdoc)
136		136
137	quiet_cmd_rustc_test_library = RUSTC TL $<	137	quiet_cmd_rustc_test_library = RUSTC TL $<
138	cmd_rustc_test_library = \	138	cmd_rustc_test_library = \
@@ -146,18 +146,18 @@ quiet_cmd_rustc_test_library = RUSTC TL $< · 7 unmodified lines
146	--crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $<	146	--crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $<
147		147
148	rusttestlib-build_error: $(src)/build_error.rs rusttest-prepare FORCE	148	rusttestlib-build_error: $(src)/build_error.rs rusttest-prepare FORCE
149	$(call if_changed,rustc_test_library)	149	+$(call if_changed,rustc_test_library)
150		150
151	rusttestlib-macros: private rustc_target_flags = --extern proc_macro	151	rusttestlib-macros: private rustc_target_flags = --extern proc_macro
152	rusttestlib-macros: private rustc_test_library_proc = yes	152	rusttestlib-macros: private rustc_test_library_proc = yes
153	rusttestlib-macros: $(src)/macros/lib.rs rusttest-prepare FORCE	153	rusttestlib-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
154	$(call if_changed,rustc_test_library)	154	+$(call if_changed,rustc_test_library)
155		155
156	rusttestlib-bindings: $(src)/bindings/lib.rs rusttest-prepare FORCE	156	rusttestlib-bindings: $(src)/bindings/lib.rs rusttest-prepare FORCE
157	$(call if_changed,rustc_test_library)	157	+$(call if_changed,rustc_test_library)
158		158
159	rusttestlib-uapi: $(src)/uapi/lib.rs rusttest-prepare FORCE	159	rusttestlib-uapi: $(src)/uapi/lib.rs rusttest-prepare FORCE
160	$(call if_changed,rustc_test_library)	160	+$(call if_changed,rustc_test_library)
161		161
162	quiet_cmd_rustdoc_test = RUSTDOC T $<	162	quiet_cmd_rustdoc_test = RUSTDOC T $<
163	cmd_rustdoc_test = \	163	cmd_rustdoc_test = \
@@ -189,7 +189,7 @@ quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $< · 25 unmodified lines
189	$(src)/kernel/lib.rs $(obj)/kernel.o \	189	$(src)/kernel/lib.rs $(obj)/kernel.o \
190	$(objtree)/scripts/rustdoc_test_builder \	190	$(objtree)/scripts/rustdoc_test_builder \
191	$(objtree)/scripts/rustdoc_test_gen FORCE	191	$(objtree)/scripts/rustdoc_test_gen FORCE
192	$(call if_changed,rustdoc_test_kernel)	192	+$(call if_changed,rustdoc_test_kernel)
193		193
194	# We cannot use `-Zpanic-abort-tests` because some tests are dynamic,	194	# We cannot use `-Zpanic-abort-tests` because some tests are dynamic,
195	# so for the moment we skip `-Cpanic=abort`.	195	# so for the moment we skip `-Cpanic=abort`.
@@ -254,21 +254,21 @@ quiet_cmd_rustsysroot = RUSTSYSROOT · 58 unmodified lines
254	$(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib	254	$(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib
255		255
256	rusttest-prepare: FORCE	256	rusttest-prepare: FORCE
257	$(call if_changed,rustsysroot)	257	+$(call if_changed,rustsysroot)
258		258
259	rusttest-macros: private rustc_target_flags = --extern proc_macro	259	rusttest-macros: private rustc_target_flags = --extern proc_macro
260	rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro	260	rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro
261	rusttest-macros: $(src)/macros/lib.rs rusttest-prepare FORCE	261	rusttest-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
262	$(call if_changed,rustc_test)	262	+$(call if_changed,rustc_test)
263	$(call if_changed,rustdoc_test)	263	+$(call if_changed,rustdoc_test)
264		264
265	rusttest-kernel: private rustc_target_flags = --extern alloc \	265	rusttest-kernel: private rustc_target_flags = --extern alloc \
266	--extern build_error --extern macros --extern bindings --extern uapi	266	--extern build_error --extern macros --extern bindings --extern uapi
267	rusttest-kernel: $(src)/kernel/lib.rs rusttest-prepare \	267	rusttest-kernel: $(src)/kernel/lib.rs rusttest-prepare \
268	rusttestlib-build_error rusttestlib-macros rusttestlib-bindings \	268	rusttestlib-build_error rusttestlib-macros rusttestlib-bindings \
269	rusttestlib-uapi FORCE	269	rusttestlib-uapi FORCE
270	$(call if_changed,rustc_test)	270	+$(call if_changed,rustc_test)
271	$(call if_changed,rustc_test_library)	271	+$(call if_changed,rustc_test_library)
272		272
273	ifdef CONFIG_CC_IS_CLANG	273	ifdef CONFIG_CC_IS_CLANG
274	bindgen_c_flags = $(c_flags)	274	bindgen_c_flags = $(c_flags)
@@ -396,7 +396,7 @@ quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@ · 121 unmodified lines
396	# Therefore, to get `libmacros.so` automatically recompiled when the compiler	396	# Therefore, to get `libmacros.so` automatically recompiled when the compiler
397	# version changes, we add `core.o` as a dependency (even if it is not needed).	397	# version changes, we add `core.o` as a dependency (even if it is not needed).
398	$(obj)/libmacros.so: $(src)/macros/lib.rs $(obj)/core.o FORCE	398	$(obj)/libmacros.so: $(src)/macros/lib.rs $(obj)/core.o FORCE
399	$(call if_changed_dep,rustc_procmacro)	399	+$(call if_changed_dep,rustc_procmacro)
400		400
401	quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@	401	quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@
402	cmd_rustc_library = \	402	cmd_rustc_library = \
@@ -435,36 +435,36 @@ $(obj)/core.o: private skip_flags = -Dunreachable_pub · 32 unmodified lines
435	$(obj)/core.o: private rustc_objcopy = $(foreach sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym))	435	$(obj)/core.o: private rustc_objcopy = $(foreach sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym))
436	$(obj)/core.o: private rustc_target_flags = $(core-cfgs)	436	$(obj)/core.o: private rustc_target_flags = $(core-cfgs)
437	$(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs scripts/target.json FORCE	437	$(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs scripts/target.json FORCE
438	$(call if_changed_dep,rustc_library)	438	+$(call if_changed_dep,rustc_library)
439		439
440	$(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*'	440	$(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*'
441	$(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE	441	$(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE
442	$(call if_changed_dep,rustc_library)	442	+$(call if_changed_dep,rustc_library)
443		443
444	$(obj)/alloc.o: private skip_clippy = 1	444	$(obj)/alloc.o: private skip_clippy = 1
445	$(obj)/alloc.o: private skip_flags = -Dunreachable_pub	445	$(obj)/alloc.o: private skip_flags = -Dunreachable_pub
446	$(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs)	446	$(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs)
447	$(obj)/alloc.o: $(src)/alloc/lib.rs $(obj)/compiler_builtins.o FORCE	447	$(obj)/alloc.o: $(src)/alloc/lib.rs $(obj)/compiler_builtins.o FORCE
448	$(call if_changed_dep,rustc_library)	448	+$(call if_changed_dep,rustc_library)
449		449
450	$(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE	450	$(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE
451	$(call if_changed_dep,rustc_library)	451	+$(call if_changed_dep,rustc_library)
452		452
453	$(obj)/bindings.o: $(src)/bindings/lib.rs \	453	$(obj)/bindings.o: $(src)/bindings/lib.rs \
454	$(obj)/compiler_builtins.o \	454	$(obj)/compiler_builtins.o \
455	$(obj)/bindings/bindings_generated.rs \	455	$(obj)/bindings/bindings_generated.rs \
456	$(obj)/bindings/bindings_helpers_generated.rs FORCE	456	$(obj)/bindings/bindings_helpers_generated.rs FORCE
457	$(call if_changed_dep,rustc_library)	457	+$(call if_changed_dep,rustc_library)
458		458
459	$(obj)/uapi.o: $(src)/uapi/lib.rs \	459	$(obj)/uapi.o: $(src)/uapi/lib.rs \
460	$(obj)/compiler_builtins.o \	460	$(obj)/compiler_builtins.o \
461	$(obj)/uapi/uapi_generated.rs FORCE	461	$(obj)/uapi/uapi_generated.rs FORCE
462	$(call if_changed_dep,rustc_library)	462	+$(call if_changed_dep,rustc_library)
463		463
464	$(obj)/kernel.o: private rustc_target_flags = --extern alloc \	464	$(obj)/kernel.o: private rustc_target_flags = --extern alloc \
465	--extern build_error --extern macros --extern bindings --extern uapi	465	--extern build_error --extern macros --extern bindings --extern uapi
466	$(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \	466	$(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \
467	$(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o FORCE	467	$(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o FORCE
468	$(call if_changed_dep,rustc_library)	468	+$(call if_changed_dep,rustc_library)
469		469
470	endif # CONFIG_RUST	470	endif # CONFIG_RUST

@@ -290,7 +290,7 @@ quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ · 289 unmodified lines
290	cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $<	290	cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $<
291		291
292	$(obj)/%.o: $(src)/%.rs FORCE	292	$(obj)/%.o: $(src)/%.rs FORCE
293	$(call if_changed_dep,rustc_o_rs)	293	+$(call if_changed_dep,rustc_o_rs)
294		294
295	quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@	295	quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
296	cmd_rustc_rsi_rs = \	296	cmd_rustc_rsi_rs = \
@@ -298,19 +298,19 @@ quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ · 1 unmodified line
298	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@	298	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@
299		299
300	$(obj)/%.rsi: $(src)/%.rs FORCE	300	$(obj)/%.rsi: $(src)/%.rs FORCE
301	$(call if_changed_dep,rustc_rsi_rs)	301	+$(call if_changed_dep,rustc_rsi_rs)
302		302
303	quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@	303	quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
304	cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $<	304	cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $<
305		305
306	$(obj)/%.s: $(src)/%.rs FORCE	306	$(obj)/%.s: $(src)/%.rs FORCE
307	$(call if_changed_dep,rustc_s_rs)	307	+$(call if_changed_dep,rustc_s_rs)
308		308
309	quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@	309	quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
310	cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $<	310	cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $<
311		311
312	$(obj)/%.ll: $(src)/%.rs FORCE	312	$(obj)/%.ll: $(src)/%.rs FORCE
313	$(call if_changed_dep,rustc_ll_rs)	313	+$(call if_changed_dep,rustc_ll_rs)
314		314
315	# Compile assembler sources (.S)	315	# Compile assembler sources (.S)
316	# ---------------------------------------------------------------------------	316	# ---------------------------------------------------------------------------