Re: [PATCH v3 7/8] mk: sort object files when building deps lists

27/06/2017 12:43, Luca Boccassi:

On Tue, 2017-06-27 at 01:20 +0200, Thomas Monjalon wrote:

quoted

23/06/2017 20:41, lboccass@brocade.com:

quoted

From: Luca Boccassi <redacted>

In order to achieve reproducible builds, always use the same
order when listing object files to build dependencies lists.

Signed-off-by: Luca Boccassi <redacted>
---
 mk/rte.app.mk     | 4 ++--
 mk/rte.hostapp.mk | 4 ++--
 mk/rte.shared.mk  | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

--- a/mk/rte.app.mk
+++ b/mk/rte.app.mk

@@ -263,8 +263,8 @@ LDLIBS_NAMES += $(patsubst -Wl$(comma)-

l%,lib%.a,$(filter -Wl$(comma)-l%,$(LDLIB
 
 # list of found libraries files (useful for deps). If not found,
the
 # library is silently ignored and dep won't be checked
-LDLIBS_FILES := $(wildcard $(foreach dir,$(LDLIBS_PATH),\
-	$(addprefix $(dir)/,$(LDLIBS_NAMES))))
+LDLIBS_FILES := $(sort $(wildcard $(foreach dir,$(LDLIBS_PATH),\
+	$(addprefix $(dir)/,$(LDLIBS_NAMES)))))

You cannot sort libraries.
Check - for instance - this comment above in this file:
	# Eliminate duplicates without sorting, only keep the last
occurrence
	filter-libs = \

Not sure I follow - what's the reason for avoiding to sort the list of
libs to link against?

Sorry, the ordering issue is with LDLIBS not LDLIBS_FILES.

quoted

Why sorting them?
What is random in libraries list?

The issue is that the output of wildcard is not fully deterministic. It
can depend on the filesystem, and even on the locale settings [1].
Before GNU Make 3.82 (2009) it used to automatically sort the output,
but that was removed (to make it faster... sigh). [2]

It is not a true wildcard here. It is just filtering files which
do not exist.
I think you do not need this patch for deterministic build.