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genksyms: track symbol checksum changes

PATCH Applied [email protected] 2 participants 2 messages Dec 1, 2008 – Dec 3, 2008 Kbuild

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PATCH 1/8 genksyms: track symbol checksum changes

From: Andreas Gruenbacher <[email protected]>

Sometimes it is preferable to avoid changes of exported symbol checksums (to avoid breaking externally provided modules). When a checksum change occurs, it can be hard to figure out what caused this change: underlying types may have changed, or additional type information may simply have become available at the point where a symbol is exported.

Add a new --reference option to genksyms which allows it to report why checksums change, based on the type information dumps it creates with the --dump-types flag. Genksyms will read in such a dump from a previous run, and report which symbols have changed (and why).

The behavior can be controlled for an entire build as follows: If KBUILD_SYMTYPES is set, genksyms uses --dump-types to produce *.symtypes dump files. If any *.symref files exist, those will be used as the reference to check against. If KBUILD_PRESERVE is set, checksum changes will fail the build.

Signed-off-by Andreas Gruenbacher <[email protected]>
Cc Sam Ravnborg <[email protected]>
Cc Randy Dunlap <[email protected]>
Signed-off-by Andrew Morton <[email protected]>

---

 scripts/Makefile.build      |   16 +-
 scripts/genksyms/genksyms.c |  236 +++++++++++++++++++++++++++++++---
 scripts/genksyms/genksyms.h |    6 
 3 files changed, 239 insertions(+), 19 deletions(-)
scripts/Makefile.build renamed from scripts/Makefile.build~genksyms-track-symbol-checksum-changes +13 -3
diff -puN scripts/Makefile.build~genksyms-track-symbol-checksum-changes scripts/Makefile.build
@@ -153,12 +153,18 @@ $(obj)/%.i: $(src)/%.c FORCE
 
 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
 cmd_cc_symtypes_c	   = \
+		set -e;							\
 		$(CPP) -D__GENKSYMS__ $(c_flags) $<			\
-		| $(GENKSYMS) -T $@ >/dev/null;				\
+		| $(GENKSYMS) -T $@					\
+			      -r $(firstword $(wildcard			\
+			      	     $(@:.symtypes=.symref) /dev/null))	\
+			      $(if $(KBUILD_PRESERVE),-p)		\
+			      -a $(ARCH)				\
+		  >/dev/null;						\
 		test -s $@ || rm -f $@
 
 $(obj)/%.symtypes : $(src)/%.c FORCE
-	$(call if_changed_dep,cc_symtypes_c)
+	$(call cmd,cc_symtypes_c)
 
 # C (.c) files
 # The C file is compiled and updated dependency information is generated.

@@ -187,7 +193,11 @@ cmd_modversions =							\
 	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then	\
 		$(CPP) -D__GENKSYMS__ $(c_flags) $<			\
 		| $(GENKSYMS) $(if $(KBUILD_SYMTYPES),			\
-			      -T $(@D)/$(@F:.o=.symtypes)) -a $(ARCH)	\
+			           -T $(@:.o=.symtypes))		\
+			      -r $(firstword $(wildcard			\
+			      	     $(@:.o=.symref) /dev/null))	\
+			      $(if $(KBUILD_PRESERVE),-p)		\
+			      -a $(ARCH)				\
 		> $(@D)/.tmp_$(@F:.o=.ver);				\
 									\
 		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 		\
scripts/genksyms/genksyms.c renamed from scripts/genksyms/genksyms.c~genksyms-track-symbol-checksum-changes +220 -16

379 lines not on this page · raw message

scripts/genksyms/genksyms.h renamed from scripts/genksyms/genksyms.h~genksyms-track-symbol-checksum-changes +6 -0
diff -puN scripts/genksyms/genksyms.h~genksyms-track-symbol-checksum-changes scripts/genksyms/genksyms.h
@@ -29,6 +29,10 @@ enum symbol_type {
 	SYM_NORMAL, SYM_TYPEDEF, SYM_ENUM, SYM_STRUCT, SYM_UNION
 };
 
+enum symbol_status {
+	STATUS_UNCHANGED, STATUS_DEFINED, STATUS_MODIFIED
+};
+
 struct string_list {
 	struct string_list *next;
 	enum symbol_type tag;

@@ -43,6 +47,8 @@ struct symbol {
 	struct symbol *expansion_trail;
 	struct symbol *visited;
 	int is_extern;
+	int is_declared;
+	enum symbol_status status;
 };
 
 typedef struct string_list **yystype;

_

Applied
#1 lore raw
Quoted 19 lines · On Mon, Dec 01, 2008 at 02:21:01PM -0800, [email protected] wrote:

From: Andreas Gruenbacher <[email protected]>

Sometimes it is preferable to avoid changes of exported symbol checksums (to avoid breaking externally provided modules). When a checksum change occurs, it can be hard to figure out what caused this change: underlying types may have changed, or additional type information may simply have become available at the point where a symbol is exported.

Add a new --reference option to genksyms which allows it to report why checksums change, based on the type information dumps it creates with the --dump-types flag. Genksyms will read in such a dump from a previous run, and report which symbols have changed (and why).

The behavior can be controlled for an entire build as follows: If KBUILD_SYMTYPES is set, genksyms uses --dump-types to produce *.symtypes dump files. If any *.symref files exist, those will be used as the reference to check against. If KBUILD_PRESERVE is set, checksum changes will fail the build.

Quoted 4 lines
Signed-off-by Andreas Gruenbacher <[email protected]>
Cc Sam Ravnborg <[email protected]>
Cc Randy Dunlap <[email protected]>
Signed-off-by Andrew Morton <[email protected]>

Applied.

Sam