[PATCH v2 2/7] kbuild: specify output names separately for each emission type from rustc

[PATCH v2 2/7] kbuild: specify output names separately for each emission type from rustc

[Masahiro Yamada]

In Kbuild, two different rules must not write to the same file, but
it happens when compiling rust source files.

For example, set CONFIG_SAMPLE_RUST_MINIMAL=m and run the following:

  $ make -j$(nproc) samples/rust/rust_minimal.o samples/rust/rust_minimal.rsi \
                    samples/rust/rust_minimal.s samples/rust/rust_minimal.ll
    [snip]
    RUSTC [M] samples/rust/rust_minimal.o
    RUSTC [M] samples/rust/rust_minimal.rsi
    RUSTC [M] samples/rust/rust_minimal.s
    RUSTC [M] samples/rust/rust_minimal.ll
  mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
  make[3]: *** [scripts/Makefile.build:334: samples/rust/rust_minimal.ll] Error 1
  make[3]: *** Waiting for unfinished jobs....
  mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
  make[3]: *** [scripts/Makefile.build:309: samples/rust/rust_minimal.o] Error 1
  mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
  make[3]: *** [scripts/Makefile.build:326: samples/rust/rust_minimal.s] Error 1
  make[2]: *** [scripts/Makefile.build:504: samples/rust] Error 2
  make[1]: *** [scripts/Makefile.build:504: samples] Error 2
  make: *** [Makefile:2008: .] Error 2

The reason for the error is that 4 threads running in parallel renames
the same file, samples/rust/rust_minimal.d.

This does not happen when compiling C or assembly files because
-Wp,-MMD,$(depfile) explicitly specifies the dependency filepath.
$(depfile) is a unique path for each target.

Currently, rustc is only given --out-dir and --emit=<list-of-types>
So, all the rust build rules output the dep-info into the default
<CRATE_NAME>.d, which causes the path conflict.

Fortunately, the --emit option is able to specify the output path
individually, with the form --emit=<type>=<path>.

Add --emit=dep-info=$(depfile) to the common part. Also, remove the
redundant --out-dir because the output path is specified for each type.

The code gets much cleaner because we do not need to rename *.d files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
---

Changes in v2:
  - Wrap a too long line

 rust/Makefile          | 11 +++++------
 scripts/Makefile.build | 14 +++++++-------
 scripts/Makefile.host  |  6 ++----
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index ff70c4c916f8..865afb87bc9b 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -331,10 +331,9 @@ $(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
 quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
       cmd_rustc_procmacro = \
 	$(RUSTC_OR_CLIPPY) $(rust_common_flags) \
-		--emit=dep-info,link --extern proc_macro \
-		--crate-type proc-macro --out-dir $(objtree)/$(obj) \
+		--emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
+		--crate-type proc-macro \
 		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \
-	mv $(objtree)/$(obj)/$(patsubst lib%.so,%,$(notdir $@)).d $(depfile); \
 	sed -i '/^\#/d' $(depfile)
 
 # Procedural macros can only be used with the `rustc` that compiled it.
@@ -348,10 +347,10 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 	OBJTREE=$(abspath $(objtree)) \
 	$(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) \
 		$(filter-out $(skip_flags),$(rust_flags) $(rustc_target_flags)) \
-		--emit=dep-info,obj,metadata --crate-type rlib \
-		--out-dir $(objtree)/$(obj) -L$(objtree)/$(obj) \
+		--emit=dep-info=$(depfile) --emit=obj=$@ \
+		--emit=metadata=$(dir $@)$(patsubst %.o,lib%.rmeta,$(notdir $@)) \
+		--crate-type rlib -L$(objtree)/$(obj) \
 		--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
-	mv $(objtree)/$(obj)/$(patsubst %.o,%,$(notdir $@)).d $(depfile); \
 	sed -i '/^\#/d' $(depfile) \
 	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
 
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a0d5c6cca76d..40de20246e50 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -285,11 +285,11 @@ rust_common_cmd = \
 	-Zcrate-attr=no_std \
 	-Zcrate-attr='feature($(rust_allowed_features))' \
 	--extern alloc --extern kernel \
-	--crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
-	--crate-name $(basename $(notdir $@))
+	--crate-type rlib -L $(objtree)/rust/ \
+	--crate-name $(basename $(notdir $@)) \
+	--emit=dep-info=$(depfile)
 
 rust_handle_depfile = \
-	mv $(obj)/$(basename $(notdir $@)).d $(depfile); \
 	sed -i '/^\#/d' $(depfile)
 
 # `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
@@ -302,7 +302,7 @@ rust_handle_depfile = \
 
 quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_o_rs = \
-	$(rust_common_cmd) --emit=dep-info,obj $<; \
+	$(rust_common_cmd) --emit=obj=$@ $<; \
 	$(rust_handle_depfile)
 
 $(obj)/%.o: $(src)/%.rs FORCE
@@ -310,7 +310,7 @@ $(obj)/%.o: $(src)/%.rs FORCE
 
 quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_rsi_rs = \
-	$(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \
+	$(rust_common_cmd) -Zunpretty=expanded $< >$@; \
 	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
 	$(rust_handle_depfile)
 
@@ -319,7 +319,7 @@ $(obj)/%.rsi: $(src)/%.rs FORCE
 
 quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_s_rs = \
-	$(rust_common_cmd) --emit=dep-info,asm $<; \
+	$(rust_common_cmd) --emit=asm=$@ $<; \
 	$(rust_handle_depfile)
 
 $(obj)/%.s: $(src)/%.rs FORCE
@@ -327,7 +327,7 @@ $(obj)/%.s: $(src)/%.rs FORCE
 
 quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_ll_rs = \
-	$(rust_common_cmd) --emit=dep-info,llvm-ir $<; \
+	$(rust_common_cmd) --emit=llvm-ir=$@ $<; \
 	$(rust_handle_depfile)
 
 $(obj)/%.ll: $(src)/%.rs FORCE
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index dea494ef55d5..67ef852712d4 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -85,7 +85,7 @@ hostc_flags    = $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS) \
 hostcxx_flags  = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
                   $(HOSTCXXFLAGS_$(target-stem).o) -Wp,-MMD,$(depfile)
 hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
-                 $(HOSTRUSTFLAGS_$(target-stem))
+                 $(HOSTRUSTFLAGS_$(target-stem)) --emit=dep-info=$(depfile)
 
 # $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
@@ -145,9 +145,7 @@ $(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
 # host-rust -> Executable
 quiet_cmd_host-rust	= HOSTRUSTC $@
       cmd_host-rust	= \
-	$(HOSTRUSTC) $(hostrust_flags) --emit=dep-info,link \
-		--out-dir=$(obj)/ $<; \
-	mv $(obj)/$(target-stem).d $(depfile); \
+	$(HOSTRUSTC) $(hostrust_flags) --emit=link=$@ $<; \
 	sed -i '/^\#/d' $(depfile)
 $(host-rust): $(obj)/%: $(src)/%.rs FORCE
 	$(call if_changed_dep,host-rust)
-- 
2.34.1

[PATCH v2 3/7] fixdep: parse Makefile more correctly to handle comments etc.

[Masahiro Yamada]

fixdep parses dependency files (*.d) emitted by the compiler.

*.d files are Makefiles describing the dependencies of the main source
file.

fixdep understands minimal Makefile syntax. It works well enough for
GCC and Clang, but not for rustc.

This commit improves the parser a little more for better processing
comments, escape sequences, etc.

My main motivation is to drop comments. rustc may output comments
(e.g. env-dep). Currentyly, rustc build rules invoke sed to remove
comments, but it is more efficient to do it in fixdep.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
---

Changes in v2:
  - Rename searching_colon -> is_target
  - More comments

 scripts/basic/fixdep.c | 173 ++++++++++++++++++++++++++++-------------
 1 file changed, 119 insertions(+), 54 deletions(-)

diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
index 37782a632494..f5a51770eb74 100644
--- a/scripts/basic/fixdep.c
+++ b/scripts/basic/fixdep.c
@@ -94,6 +94,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
+#include <stdbool.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <ctype.h>
@@ -251,75 +252,139 @@ static int is_ignored_file(const char *s, int len)
  * assignments are parsed not only by make, but also by the rather simple
  * parser in scripts/mod/sumversion.c.
  */
-static void parse_dep_file(char *m, const char *target)
+static void parse_dep_file(char *p, const char *target)
 {
-	char *p;
-	int is_last, is_target;
-	int saw_any_target = 0;
-	int is_first_dep = 0;
-	void *buf;
-
-	while (1) {
-		/* Skip any "white space" */
-		while (*m == ' ' || *m == '\\' || *m == '\n')
-			m++;
-
-		if (!*m)
+	bool saw_any_target = false;
+	bool is_target = true;
+	bool is_source = false;
+	bool need_parse;
+	char *q, saved_c;
+
+	while (*p) {
+		/* handle some special characters first. */
+		switch (*p) {
+		case '#':
+			/*
+			 * skip comments.
+			 * rustc may emit comments to dep-info.
+			 */
+			p++;
+			while (*p != '\0' && *p != '\n') {
+				/*
+				 * escaped newlines continue the comment across
+				 * multiple lines.
+				 */
+				if (*p == '\\')
+					p++;
+				p++;
+			}
+			continue;
+		case ' ':
+		case '\t':
+			/* skip whitespaces */
+			p++;
+			continue;
+		case '\\':
+			/*
+			 * backslash/newline combinations continue the
+			 * statement. Skip it just like a whitespace.
+			 */
+			if (*(p + 1) == '\n') {
+				p += 2;
+				continue;
+			}
 			break;
-
-		/* Find next "white space" */
-		p = m;
-		while (*p && *p != ' ' && *p != '\\' && *p != '\n')
+		case '\n':
+			/*
+			 * Makefiles use a line-based syntax, where the newline
+			 * is the end of a statement. After seeing a newline,
+			 * we expect the next token is a target.
+			 */
 			p++;
-		is_last = (*p == '\0');
-		/* Is the token we found a target name? */
-		is_target = (*(p-1) == ':');
-		/* Don't write any target names into the dependency file */
-		if (is_target) {
-			/* The /next/ file is the first dependency */
-			is_first_dep = 1;
-		} else if (!is_ignored_file(m, p - m)) {
-			*p = '\0';
-
+			is_target = true;
+			continue;
+		case ':':
 			/*
-			 * Do not list the source file as dependency, so that
-			 * kbuild is not confused if a .c file is rewritten
-			 * into .S or vice versa. Storing it in source_* is
-			 * needed for modpost to compute srcversions.
+			 * assume the first dependency after a colon as the
+			 * source file.
 			 */
-			if (is_first_dep) {
+			p++;
+			is_target = false;
+			is_source = true;
+			continue;
+		}
+
+		/* find the end of the token */
+		q = p;
+		while (*q != ' ' && *q != '\t' && *q != '\n' && *q != '#' && *q != ':') {
+			if (*q == '\\') {
 				/*
-				 * If processing the concatenation of multiple
-				 * dependency files, only process the first
-				 * target name, which will be the original
-				 * source name, and ignore any other target
-				 * names, which will be intermediate temporary
-				 * files.
+				 * backslash/newline combinations work like as
+				 * a whitespace, so this is the end of token.
 				 */
-				if (!saw_any_target) {
-					saw_any_target = 1;
-					printf("source_%s := %s\n\n",
-					       target, m);
-					printf("deps_%s := \\\n", target);
+				if (*(q + 1) == '\n')
+					break;
+
+				/* escaped special characters */
+				if (*(q + 1) == '#' || *(q + 1) == ':') {
+					memmove(p + 1, p, q - p);
+					p++;
 				}
-				is_first_dep = 0;
-			} else {
-				printf("  %s \\\n", m);
+
+				q++;
 			}
 
-			buf = read_file(m);
-			parse_config_file(buf);
-			free(buf);
+			if (*q == '\0')
+				break;
+			q++;
 		}
 
-		if (is_last)
-			break;
+		/* Just discard the target */
+		if (is_target) {
+			p = q;
+			continue;
+		}
+
+		saved_c = *q;
+		*q = '\0';
+		need_parse = false;
 
 		/*
-		 * Start searching for next token immediately after the first
-		 * "whitespace" character that follows this token.
+		 * Do not list the source file as dependency, so that kbuild is
+		 * not confused if a .c file is rewritten into .S or vice versa.
+		 * Storing it in source_* is needed for modpost to compute
+		 * srcversions.
 		 */
-		m = p + 1;
+		if (is_source) {
+			/*
+			 * The DT build rule concatenates multiple dep files.
+			 * When processing them, only process the first source
+			 * name, which will be the original one, and ignore any
+			 * other source names, which will be intermediate
+			 * temporary files.
+			 */
+			if (!saw_any_target) {
+				saw_any_target = true;
+				printf("source_%s := %s\n\n", target, p);
+				printf("deps_%s := \\\n", target);
+				need_parse = true;
+			}
+		} else if (!is_ignored_file(p, q - p)) {
+			printf("  %s \\\n", p);
+			need_parse = true;
+		}
+
+		if (need_parse) {
+			void *buf;
+
+			buf = read_file(p);
+			parse_config_file(buf);
+			free(buf);
+		}
+
+		is_source = false;
+		*q = saved_c;
+		p = q;
 	}
 
 	if (!saw_any_target) {
-- 
2.34.1

[PATCH v2 4/7] kbuild: remove sed commands after rustc rules

[Masahiro Yamada]

rustc may put comments in dep-info, so sed is used to drop them before
passing it to fixdep.

Now that fixdep can remove comments, Makefiles do not need to run sed.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
---

(no changes since v1)

 rust/Makefile          |  6 ++----
 scripts/Makefile.build | 18 ++++--------------
 scripts/Makefile.host  |  3 +--
 3 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index 865afb87bc9b..f403b79cae5a 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -333,8 +333,7 @@ quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
 	$(RUSTC_OR_CLIPPY) $(rust_common_flags) \
 		--emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
 		--crate-type proc-macro \
-		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \
-	sed -i '/^\#/d' $(depfile)
+		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<
 
 # Procedural macros can only be used with the `rustc` that compiled it.
 # Therefore, to get `libmacros.so` automatically recompiled when the compiler
@@ -350,8 +349,7 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 		--emit=dep-info=$(depfile) --emit=obj=$@ \
 		--emit=metadata=$(dir $@)$(patsubst %.o,lib%.rmeta,$(notdir $@)) \
 		--crate-type rlib -L$(objtree)/$(obj) \
-		--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
-	sed -i '/^\#/d' $(depfile) \
+		--crate-name $(patsubst %.o,%,$(notdir $@)) $< \
 	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
 
 rust-analyzer:
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 40de20246e50..76323201232a 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -289,9 +289,6 @@ rust_common_cmd = \
 	--crate-name $(basename $(notdir $@)) \
 	--emit=dep-info=$(depfile)
 
-rust_handle_depfile = \
-	sed -i '/^\#/d' $(depfile)
-
 # `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
 # will be used. We explicitly request `-Ccodegen-units=1` in any case, and
 # the compiler shows a warning if it is not 1. However, if we ever stop
@@ -301,9 +298,7 @@ rust_handle_depfile = \
 # would not match each other.
 
 quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
-      cmd_rustc_o_rs = \
-	$(rust_common_cmd) --emit=obj=$@ $<; \
-	$(rust_handle_depfile)
+      cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $<
 
 $(obj)/%.o: $(src)/%.rs FORCE
 	$(call if_changed_dep,rustc_o_rs)
@@ -311,24 +306,19 @@ $(obj)/%.o: $(src)/%.rs FORCE
 quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_rsi_rs = \
 	$(rust_common_cmd) -Zunpretty=expanded $< >$@; \
-	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
-	$(rust_handle_depfile)
+	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@
 
 $(obj)/%.rsi: $(src)/%.rs FORCE
 	$(call if_changed_dep,rustc_rsi_rs)
 
 quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
-      cmd_rustc_s_rs = \
-	$(rust_common_cmd) --emit=asm=$@ $<; \
-	$(rust_handle_depfile)
+      cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $<
 
 $(obj)/%.s: $(src)/%.rs FORCE
 	$(call if_changed_dep,rustc_s_rs)
 
 quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
-      cmd_rustc_ll_rs = \
-	$(rust_common_cmd) --emit=llvm-ir=$@ $<; \
-	$(rust_handle_depfile)
+      cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $<
 
 $(obj)/%.ll: $(src)/%.rs FORCE
 	$(call if_changed_dep,rustc_ll_rs)
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 67ef852712d4..a45a97b027d1 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -145,8 +145,7 @@ $(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
 # host-rust -> Executable
 quiet_cmd_host-rust	= HOSTRUSTC $@
       cmd_host-rust	= \
-	$(HOSTRUSTC) $(hostrust_flags) --emit=link=$@ $<; \
-	sed -i '/^\#/d' $(depfile)
+	$(HOSTRUSTC) $(hostrust_flags) --emit=link=$@ $<
 $(host-rust): $(obj)/%: $(src)/%.rs FORCE
 	$(call if_changed_dep,host-rust)
 
-- 
2.34.1