diff mbox series

[kvm-unit-tests] configure: Test if compiler supports -m16 on x86

Message ID 20200924182401.95891-1-r.bolshakov@yadro.com (mailing list archive)
State New, archived
Headers show
Series [kvm-unit-tests] configure: Test if compiler supports -m16 on x86 | expand

Commit Message

Roman Bolshakov Sept. 24, 2020, 6:24 p.m. UTC 
-m16 option is available only since GCC 4.9.0 [1]. That causes a build
failure on centos-7 [2] that has GCC 4.8.5.

Fallback to -m32 if -m16 is not available.

1. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59672
2. https://gitlab.com/bonzini/kvm-unit-tests/-/jobs/755368387

Fixes: 2616ad934e2 ("x86: realmode: Workaround clang issues")
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
---
 configure           | 11 +++++++++++
 x86/Makefile.common |  4 ++++
 2 files changed, 15 insertions(+)

Comments

Thomas Huth Sept. 25, 2020, 6:45 a.m. UTC | #1 
On 24/09/2020 20.24, Roman Bolshakov wrote:
> -m16 option is available only since GCC 4.9.0 [1]. That causes a build
> failure on centos-7 [2] that has GCC 4.8.5.
> 
> Fallback to -m32 if -m16 is not available.
> 
> 1. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59672
> 2. https://gitlab.com/bonzini/kvm-unit-tests/-/jobs/755368387
> 
> Fixes: 2616ad934e2 ("x86: realmode: Workaround clang issues")
> Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
> ---
>  configure           | 11 +++++++++++
>  x86/Makefile.common |  4 ++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/configure b/configure
> index f930543..7dc2e3b 100755
> --- a/configure
> +++ b/configure
> @@ -16,6 +16,7 @@ pretty_print_stacks=yes
>  environ_default=yes
>  u32_long=
>  wa_divide=
> +m16_support=
>  vmm="qemu"
>  errata_force=0
>  erratatxt="$srcdir/errata.txt"
> @@ -167,6 +168,15 @@ EOF
>    rm -f lib-test.{o,S}
>  fi
>  
> +# check if -m16 is supported
> +if [ "$arch" = "i386" ] || [ "$arch" = "x86_64" ]; then
> +  cat << EOF > lib-test.c
> +int f(int a, int b) { return a + b; }
> +EOF
> +  m16_support=$("$cross_prefix$cc" -m16 -c lib-test.c >/dev/null 2>&1 && echo yes)
> +  rm -f lib-test.{o,c}
> +fi
> +
>  # require enhanced getopt
>  getopt -T > /dev/null
>  if [ $? -ne 4 ]; then
> @@ -224,6 +234,7 @@ ENVIRON_DEFAULT=$environ_default
>  ERRATATXT=$erratatxt
>  U32_LONG_FMT=$u32_long
>  WA_DIVIDE=$wa_divide
> +M16_SUPPORT=$m16_support
>  EOF
>  
>  cat <<EOF > lib/config.h
> diff --git a/x86/Makefile.common b/x86/Makefile.common
> index 5567d66..553bf49 100644
> --- a/x86/Makefile.common
> +++ b/x86/Makefile.common
> @@ -72,7 +72,11 @@ $(TEST_DIR)/realmode.elf: $(TEST_DIR)/realmode.o
>  	$(CC) -m32 -nostdlib -o $@ -Wl,-m,elf_i386 \
>  	      -Wl,-T,$(SRCDIR)/$(TEST_DIR)/realmode.lds $^
>  
> +ifeq ($(M16_SUPPORT),yes)
>  $(TEST_DIR)/realmode.o: bits = 16
> +else
> +$(TEST_DIR)/realmode.o: bits = 32
> +endif
>  
>  $(TEST_DIR)/kvmclock_test.elf: $(TEST_DIR)/kvmclock.o
>  
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>
Paolo Bonzini Sept. 25, 2020, 7:17 a.m. UTC | #2 
On 24/09/20 20:24, Roman Bolshakov wrote:
> -m16 option is available only since GCC 4.9.0 [1]. That causes a build
> failure on centos-7 [2] that has GCC 4.8.5.
> 
> Fallback to -m32 if -m16 is not available.
> 
> 1. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59672
> 2. https://gitlab.com/bonzini/kvm-unit-tests/-/jobs/755368387
> 
> Fixes: 2616ad934e2 ("x86: realmode: Workaround clang issues")
> Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>

This is a simpler way to do it:

diff --git a/x86/Makefile.common b/x86/Makefile.common
index 5567d66..781dba6 100644
--- a/x86/Makefile.common
+++ b/x86/Makefile.common
@@ -72,7 +72,7 @@ $(TEST_DIR)/realmode.elf: $(TEST_DIR)/realmode.o
 	$(CC) -m32 -nostdlib -o $@ -Wl,-m,elf_i386 \
 	      -Wl,-T,$(SRCDIR)/$(TEST_DIR)/realmode.lds $^
 
-$(TEST_DIR)/realmode.o: bits = 16
+$(TEST_DIR)/realmode.o: bits := $(if $(call cc-option,-m16,""),16,32)
 
 $(TEST_DIR)/kvmclock_test.elf: $(TEST_DIR)/kvmclock.o

It's a tiny bit slower because the check is done on every compilation,
but only if realmode.o is stale.

It passes CI (https://gitlab.com/bonzini/kvm-unit-tests/-/pipelines/194356382)
so I plan to commit it.

Paolo

> ---
>  configure           | 11 +++++++++++
>  x86/Makefile.common |  4 ++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/configure b/configure
> index f930543..7dc2e3b 100755
> --- a/configure
> +++ b/configure
> @@ -16,6 +16,7 @@ pretty_print_stacks=yes
>  environ_default=yes
>  u32_long=
>  wa_divide=
> +m16_support=
>  vmm="qemu"
>  errata_force=0
>  erratatxt="$srcdir/errata.txt"
> @@ -167,6 +168,15 @@ EOF
>    rm -f lib-test.{o,S}
>  fi
>  
> +# check if -m16 is supported
> +if [ "$arch" = "i386" ] || [ "$arch" = "x86_64" ]; then
> +  cat << EOF > lib-test.c
> +int f(int a, int b) { return a + b; }
> +EOF
> +  m16_support=$("$cross_prefix$cc" -m16 -c lib-test.c >/dev/null 2>&1 && echo yes)
> +  rm -f lib-test.{o,c}
> +fi
> +
>  # require enhanced getopt
>  getopt -T > /dev/null
>  if [ $? -ne 4 ]; then
> @@ -224,6 +234,7 @@ ENVIRON_DEFAULT=$environ_default
>  ERRATATXT=$erratatxt
>  U32_LONG_FMT=$u32_long
>  WA_DIVIDE=$wa_divide
> +M16_SUPPORT=$m16_support
>  EOF
>  
>  cat <<EOF > lib/config.h
> diff --git a/x86/Makefile.common b/x86/Makefile.common
> index 5567d66..553bf49 100644
> --- a/x86/Makefile.common
> +++ b/x86/Makefile.common
> @@ -72,7 +72,11 @@ $(TEST_DIR)/realmode.elf: $(TEST_DIR)/realmode.o
>  	$(CC) -m32 -nostdlib -o $@ -Wl,-m,elf_i386 \
>  	      -Wl,-T,$(SRCDIR)/$(TEST_DIR)/realmode.lds $^
>  
> +ifeq ($(M16_SUPPORT),yes)
>  $(TEST_DIR)/realmode.o: bits = 16
> +else
> +$(TEST_DIR)/realmode.o: bits = 32
> +endif
>  
>  $(TEST_DIR)/kvmclock_test.elf: $(TEST_DIR)/kvmclock.o
>  
>
Roman Bolshakov Sept. 25, 2020, 9:16 a.m. UTC | #3 
On Fri, Sep 25, 2020 at 09:17:00AM +0200, Paolo Bonzini wrote:
> On 24/09/20 20:24, Roman Bolshakov wrote:
> > -m16 option is available only since GCC 4.9.0 [1]. That causes a build
> > failure on centos-7 [2] that has GCC 4.8.5.
> > 
> > Fallback to -m32 if -m16 is not available.
> > 
> > 1. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59672
> > 2. https://gitlab.com/bonzini/kvm-unit-tests/-/jobs/755368387
> > 
> > Fixes: 2616ad934e2 ("x86: realmode: Workaround clang issues")
> > Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
> 
> This is a simpler way to do it:
> 
> diff --git a/x86/Makefile.common b/x86/Makefile.common
> index 5567d66..781dba6 100644
> --- a/x86/Makefile.common
> +++ b/x86/Makefile.common
> @@ -72,7 +72,7 @@ $(TEST_DIR)/realmode.elf: $(TEST_DIR)/realmode.o
>  	$(CC) -m32 -nostdlib -o $@ -Wl,-m,elf_i386 \
>  	      -Wl,-T,$(SRCDIR)/$(TEST_DIR)/realmode.lds $^
>  
> -$(TEST_DIR)/realmode.o: bits = 16
> +$(TEST_DIR)/realmode.o: bits := $(if $(call cc-option,-m16,""),16,32)
>  
>  $(TEST_DIR)/kvmclock_test.elf: $(TEST_DIR)/kvmclock.o
> 
> It's a tiny bit slower because the check is done on every compilation,
> but only if realmode.o is stale.
> 
> It passes CI (https://gitlab.com/bonzini/kvm-unit-tests/-/pipelines/194356382)
> so I plan to commit it.
> 

That's fine,
Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>

Thanks,
Roman
diff mbox series

Patch

diff --git a/configure b/configure
index f930543..7dc2e3b 100755
--- a/configure
+++ b/configure
@@ -16,6 +16,7 @@  pretty_print_stacks=yes
 environ_default=yes
 u32_long=
 wa_divide=
+m16_support=
 vmm="qemu"
 errata_force=0
 erratatxt="$srcdir/errata.txt"
@@ -167,6 +168,15 @@  EOF
   rm -f lib-test.{o,S}
 fi
 
+# check if -m16 is supported
+if [ "$arch" = "i386" ] || [ "$arch" = "x86_64" ]; then
+  cat << EOF > lib-test.c
+int f(int a, int b) { return a + b; }
+EOF
+  m16_support=$("$cross_prefix$cc" -m16 -c lib-test.c >/dev/null 2>&1 && echo yes)
+  rm -f lib-test.{o,c}
+fi
+
 # require enhanced getopt
 getopt -T > /dev/null
 if [ $? -ne 4 ]; then
@@ -224,6 +234,7 @@  ENVIRON_DEFAULT=$environ_default
 ERRATATXT=$erratatxt
 U32_LONG_FMT=$u32_long
 WA_DIVIDE=$wa_divide
+M16_SUPPORT=$m16_support
 EOF
 
 cat <<EOF > lib/config.h
diff --git a/x86/Makefile.common b/x86/Makefile.common
index 5567d66..553bf49 100644
--- a/x86/Makefile.common
+++ b/x86/Makefile.common
@@ -72,7 +72,11 @@  $(TEST_DIR)/realmode.elf: $(TEST_DIR)/realmode.o
 	$(CC) -m32 -nostdlib -o $@ -Wl,-m,elf_i386 \
 	      -Wl,-T,$(SRCDIR)/$(TEST_DIR)/realmode.lds $^
 
+ifeq ($(M16_SUPPORT),yes)
 $(TEST_DIR)/realmode.o: bits = 16
+else
+$(TEST_DIR)/realmode.o: bits = 32
+endif
 
 $(TEST_DIR)/kvmclock_test.elf: $(TEST_DIR)/kvmclock.o