One source of complexity in the QEMU source is that we have a very
shallow tree for a source code of over 750,000 lines of code. In
fact, one third of these lines alone is in one directory, hw/.
As a prerequisite to cleaning up the structure, but as a worthwhile
step on its own, this patchset cleans up the build system so that
separate directories have their own Makefile snippet. As in the Linux
kernel build system, the overall build system is generally flat (in
the case of QEMU, with one recursive invocation per emulation target).
Subdirectories do not include complete Makefiles, instead they only host
the declarations for a few variables (common-obj-y, universal-obj-y,
obj-y, etc.). Definitions for all the directories are merged with a
little GNU Make magic (not much, only 20 lines).
Two nice side effects are:
- we can match the source tree and the object tree (for example the
per-target device models will be in XYZ-softmmu/hw, not in
XYZ-softmmu; those that are compiled once will be in hw/ rather
than in the root).
- because the resolution of nested makefiles tracks the nested
directory, there is no need to use VPATH to find sources in
the hw/ and target-*/ directory.
- there is a lot less Makefile programming (conditionals, addprefix,
etc.), replaced by only 20 lines in rules.mak and 1 in Makefile.objs.
The series is entirely bisectable, and mostly consists of boring patches.
If the concept is accepted, I would like to get it in as soon as possible.
I have a few other cleanups on top (I stopped once I undid the diffstat
of this series :)), but they can be covered later.
Thoughts, approvals, rejections?
Paolo
Paolo Bonzini (24):
remove trace-nested-y
do not sprinkle around GENERATED_HEADERS dependencies
add rules for nesting
move *-user/ objects to nested Makefile
move obj-TARGET-y variables to nested Makefile
move libobj-y variable to nested Makefile
move other target-*/ objects to nested Makefiles
move rules for nesting to Makefile.objs
use nested Makefile rules for qom/ objects
move block/ objects to nested Makefile
move net/ objects to nested Makefile
move fsdev/ objects to nested Makefile
move ui/ objects to nested Makefile
move audio/ objects to nested Makefile
move slirp/ objects to nested Makefile
move qapi/ objects to nested Makefile
move qga/ objects to nested Makefile
move target-independent hw/ objects to nested Makefiles
convert libhw to nested Makefiles
move per-target hw/ objects to nested Makefiles
move device tree to per-target Makefile
libcacard Makefile cleanups
limit usage of vpath
compile oslib-obj-y once
Makefile | 30 ++-
Makefile.hw | 7 +-
Makefile.objs | 316 ++++---------------------
Makefile.target | 325 ++++----------------------
audio/Makefile | 15 ++
block/Makefile | 11 +
bsd-user/Makefile | 3 +
configure | 70 +++---
fsdev/Makefile | 6 +
hw/9pfs/Makefile | 9 +
hw/Makefile | 162 +++++++++++++
hw/alpha/Makefile | 4 +
hw/arm/Makefile | 40 ++++
hw/cris/Makefile | 13 ++
hw/i386/Makefile | 13 ++
hw/ide/Makefile | 10 +
hw/lm32/Makefile | 23 ++
hw/m68k/Makefile | 4 +
hw/microblaze/Makefile | 14 ++
hw/mips/Makefile | 6 +
hw/ppc/Makefile | 32 +++
hw/s390x/Makefile | 3 +
hw/sh4/Makefile | 5 +
hw/sparc/Makefile | 8 +
hw/sparc64/Makefile | 4 +
hw/usb/Makefile | 13 ++
hw/xtensa/Makefile | 5 +
libcacard/Makefile | 17 +-
linux-user/Makefile | 7 +
linux-user/arm/nwfpe/Makefile | 3 +
net/Makefile | 13 ++
qapi/Makefile | 3 +
qga/Makefile | 4 +
qom/Makefile | 6 +-
rules.mak | 21 ++
slirp/Makefile | 4 +
target-alpha/Makefile | 3 +
target-arm/Makefile | 4 +
arm-semi.c => target-arm/arm-semi.c | 0
target-cris/Makefile | 2 +
target-i386/Makefile | 6 +
ioport-user.c => target-i386/ioport-user.c | 0
target-lm32/Makefile | 2 +
target-m68k/Makefile | 3 +
m68k-semi.c => target-m68k/m68k-semi.c | 0
target-microblaze/Makefile | 2 +
target-mips/Makefile | 2 +
target-ppc/Makefile | 3 +
target-s390x/Makefile | 3 +
target-sh4/Makefile | 2 +
target-sparc/Makefile | 6 +
target-unicore32/Makefile | 2 +
target-xtensa/Makefile | 6 +
xtensa-semi.c => target-xtensa/xtensa-semi.c | 0
tests/Makefile | 1 -
ui/Makefile | 18 ++
56 files changed, 674 insertions(+), 620 deletions(-)
create mode 100644 audio/Makefile
create mode 100644 block/Makefile
create mode 100644 bsd-user/Makefile
create mode 100644 fsdev/Makefile
create mode 100644 hw/9pfs/Makefile
create mode 100644 hw/Makefile
create mode 100644 hw/alpha/Makefile
create mode 100644 hw/arm/Makefile
create mode 100644 hw/cris/Makefile
create mode 100644 hw/i386/Makefile
create mode 100644 hw/ide/Makefile
create mode 100644 hw/lm32/Makefile
create mode 100644 hw/m68k/Makefile
create mode 100644 hw/microblaze/Makefile
create mode 100644 hw/mips/Makefile
create mode 100644 hw/ppc/Makefile
create mode 100644 hw/s390x/Makefile
create mode 100644 hw/sh4/Makefile
create mode 100644 hw/sparc/Makefile
create mode 100644 hw/sparc64/Makefile
create mode 100644 hw/usb/Makefile
create mode 100644 hw/xtensa/Makefile
create mode 100644 linux-user/Makefile
create mode 100644 linux-user/arm/nwfpe/Makefile
create mode 100644 net/Makefile
create mode 100644 qapi/Makefile
create mode 100644 qga/Makefile
create mode 100644 slirp/Makefile
create mode 100644 target-alpha/Makefile
create mode 100644 target-arm/Makefile
rename arm-semi.c => target-arm/arm-semi.c (100%)
create mode 100644 target-cris/Makefile
create mode 100644 target-i386/Makefile
rename ioport-user.c => target-i386/ioport-user.c (100%)
create mode 100644 target-lm32/Makefile
create mode 100644 target-m68k/Makefile
rename m68k-semi.c => target-m68k/m68k-semi.c (100%)
create mode 100644 target-microblaze/Makefile
create mode 100644 target-mips/Makefile
create mode 100644 target-ppc/Makefile
create mode 100644 target-s390x/Makefile
create mode 100644 target-sh4/Makefile
create mode 100644 target-sparc/Makefile
create mode 100644 target-unicore32/Makefile
create mode 100644 target-xtensa/Makefile
rename xtensa-semi.c => target-xtensa/xtensa-semi.c (100%)
create mode 100644 ui/Makefile