Re: [Qemu-devel] [PATCH] make: explicit dependencies for ACPI gen sources

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

On Tue, Aug 04, 2015 at 07:21:25PM +0300, Victor Kaplansky wrote:
> Rebuilding QEMU after switching versions from git can cause make failure
> if IASL is enabled. This is caused by including stale *.d info from
> previous build.
> 
> To prevent this in the future we generate dependency info for generated
> ACPI sources in *.dep instead regular *.d and include them explicitly.
> This will allow us not to break future builds when one of such generated
> sources is removed - by removing explicit include of removed dependency.
> 
> By itself this doesn't fix broken builds from the past and this will be
> done by the following patch.

I wonder how do you plan to do this.
One simple way would be to rename .hex files to something else.
Without an implicit rule for making .hex from .dsl, stale
dependencies on .hex would be harmless.

> 
> Signed-off-by: Victor Kaplansky <victork@redhat.com>
> ---
>  hw/i386/Makefile.objs | 4 +++-
>  rules.mak             | 1 +
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/Makefile.objs b/hw/i386/Makefile.objs
> index bd4f147..bcc7083 100644
> --- a/hw/i386/Makefile.objs
> +++ b/hw/i386/Makefile.objs
> @@ -10,13 +10,15 @@ obj-y += acpi-build.o
>  hw/i386/acpi-build.o: hw/i386/acpi-build.c \
>  	hw/i386/acpi-dsdt.hex hw/i386/q35-acpi-dsdt.hex
>  
> +-include hw/i386/acpi-dsdt.dep hw/i386/q35-acpi-dsdt.dep
> +
>  iasl-option=$(shell if test -z "`$(1) $(2) 2>&1 > /dev/null`" \
>      ; then echo "$(2)"; else echo "$(3)"; fi ;)
>  
>  ifdef IASL
>  #IASL Present. Generate hex files from .dsl
>  hw/i386/%.hex: $(SRC_PATH)/hw/i386/%.dsl $(SRC_PATH)/scripts/acpi_extract_preprocess.py $(SRC_PATH)/scripts/acpi_extract.py
> -	$(call quiet-command, $(CPP) -x c -P $(QEMU_DGFLAGS) $(QEMU_INCLUDES) $< -o $*.dsl.i.orig, "  CPP $(TARGET_DIR)$*.dsl.i.orig")
> +	$(call quiet-command, $(CPP) -x c -P $(QEMU_DGFLAGS_GEN) $(QEMU_INCLUDES) $< -o $*.dsl.i.orig, "  CPP $(TARGET_DIR)$*.dsl.i.orig")
>  	$(call quiet-command, $(PYTHON) $(SRC_PATH)/scripts/acpi_extract_preprocess.py $*.dsl.i.orig > $*.dsl.i, "  ACPI_PREPROCESS $(TARGET_DIR)$*.dsl.i")
>  	$(call quiet-command, $(IASL) $(call iasl-option,$(IASL),-Pn,) -vs -l -tc -p $* $*.dsl.i $(if $(V), , > /dev/null) 2>&1 ,"  IASL $(TARGET_DIR)$*.dsl.i")
>  	$(call quiet-command, $(PYTHON) $(SRC_PATH)/scripts/acpi_extract.py $*.lst > $*.off, "  ACPI_EXTRACT $(TARGET_DIR)$*.off")
> diff --git a/rules.mak b/rules.mak
> index aec27f8..6019a46 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -18,6 +18,7 @@ QEMU_CXXFLAGS = -D__STDC_LIMIT_MACROS $(filter-out -Wstrict-prototypes -Wmissing
>  
>  # Flags for dependency generation
>  QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(*D)/$(*F).d
> +QEMU_DGFLAGS_GEN += -MMD -MP -MT $@ -MF $(*D)/$(*F).dep
>  
>  # Same as -I$(SRC_PATH) -I., but for the nested source/object directories
>  QEMU_INCLUDES += -I$(<D) -I$(@D)
> -- 
> --Victor