Re: [Qemu-devel] [PATCH v2 1/2] make: fix where dependency *.d are stored.

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Aug 06, 2015 at 09:57:03AM +0100, Alex Bennée wrote:
> 
> Victor Kaplansky <victork@redhat.com> writes:
> 
> > In rules like "bar/%.o: %.c" there is a difference between $(*D) and
> > $(@D). It is cleaner to generate *.d next to appropriate *.o, because it
> > allows precise including of dependency info from .d files.
> 
> It might be worth putting the example in the comment as most people are
> not familiar with the esoteric symbolic of GNU Make. AIUI in your
> example $(@D) resolves to "bar" instead of "bar/%"
> 
> >
> > As a hack, we also touch two sources for generated *.hex files. This is
> > to ensure *.hex rebuild, when old revision is switched to the new one.
> 
> While I'm sure this was useful for testing do we really want to include
> such a hack in the git history?

This is the hint for why it's needed there:
"This is to ensure *.hex rebuild, when old revision is switched to the
new one."
Maybe add this, making this more explicit:
	Without this hack, anyone doing "git pull; make" will not get *.hex rebuilt
	correctly since the dependency file would be missing.


> >
> > Signed-off-by: Victor Kaplansky <victork@redhat.com>
> > ---
> >  hw/i386/acpi-dsdt.dsl     | 1 -
> >  hw/i386/q35-acpi-dsdt.dsl | 1 +
> >  rules.mak                 | 2 +-
> >  3 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/i386/acpi-dsdt.dsl b/hw/i386/acpi-dsdt.dsl
> > index a2d84ec..8dba096 100644
> > --- a/hw/i386/acpi-dsdt.dsl
> > +++ b/hw/i386/acpi-dsdt.dsl
> > @@ -43,7 +43,6 @@ DefinitionBlock (
> >  
> >  #include "acpi-dsdt-hpet.dsl"
> >  
> > -
> >  /****************************************************************
> >   * PIIX4 PM
> >   ****************************************************************/
> > diff --git a/hw/i386/q35-acpi-dsdt.dsl b/hw/i386/q35-acpi-dsdt.dsl
> > index 16eaca3..7be7b37 100644
> > --- a/hw/i386/q35-acpi-dsdt.dsl
> > +++ b/hw/i386/q35-acpi-dsdt.dsl
> > @@ -22,6 +22,7 @@
> >   * Based on acpi-dsdt.dsl, but heavily modified for q35 chipset.
> >   */
> >  
> > +
> >  ACPI_EXTRACT_ALL_CODE Q35AcpiDsdtAmlCode
> >  
> >  DefinitionBlock (
> > diff --git a/rules.mak b/rules.mak
> > index aec27f8..6e35c36 100644
> > --- a/rules.mak
> > +++ b/rules.mak
> > @@ -17,7 +17,7 @@ MAKEFLAGS += -rR
> >  QEMU_CXXFLAGS = -D__STDC_LIMIT_MACROS $(filter-out -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Wold-style-declaration -Wold-style-definition -Wredundant-decls, $(QEMU_CFLAGS))
> >  
> >  # Flags for dependency generation
> > -QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(*D)/$(*F).d
> > +QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(@D)/$(*F).d
> >  
> >  # Same as -I$(SRC_PATH) -I., but for the nested source/object directories
> >  QEMU_INCLUDES += -I$(<D) -I$(@D)
> 
> -- 
> Alex Bennée