[PATCH] Use -fno-omit-frame-pointer in addition to -g

[PATCH] Use -fno-omit-frame-pointer in addition to -g

[Samuel Thibault]

Use -fno-omit-frame-pointer in addition to -g
as that permits to use simple stack walk while debugging

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

diff -r fb74347d80c3 Config.mk
--- a/Config.mk	Wed Mar 05 12:20:40 2008 +0000
+++ b/Config.mk	Thu Mar 06 15:52:14 2008 +0000
@@ -55,7 +55,7 @@ endef
 endef
 
 ifeq ($(debug),y)
-CFLAGS += -g
+CFLAGS += -g -fno-omit-frame-pointer
 endif
 
 CFLAGS += -fno-strict-aliasing
diff -r fb74347d80c3 extras/mini-os/minios.mk
--- a/extras/mini-os/minios.mk	Wed Mar 05 12:20:40 2008 +0000
+++ b/extras/mini-os/minios.mk	Thu Mar 06 15:52:14 2008 +0000
@@ -15,7 +15,7 @@ DEF_LDFLAGS =
 DEF_LDFLAGS =
 
 ifeq ($(debug),y)
-DEF_CFLAGS += -g
+DEF_CFLAGS += -g -fno-omit-frame-pointer
 else
 DEF_CFLAGS += -O3
 endif

[PATCH2] Don't optimize function calls with -g

[Samuel Thibault]

Samuel Thibault, le Thu 06 Mar 2008 15:55:09 +0000, a écrit :
> Use -fno-omit-frame-pointer in addition to -g
> as that permits to use simple stack walk while debugging

Even better:



Don't optimize function calls with -g
-fno-omit-frame-pointer to easily walk the stack
-fno-optimize-sibling-calls to not miss a step

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

diff -r fb74347d80c3 Config.mk
--- a/Config.mk	Wed Mar 05 12:20:40 2008 +0000
+++ b/Config.mk	Thu Mar 06 15:57:53 2008 +0000
@@ -55,7 +55,7 @@ endef
 endef
 
 ifeq ($(debug),y)
-CFLAGS += -g
+CFLAGS += -g -fno-omit-frame-pointer -fno-optimize-sibling-calls
 endif
 
 CFLAGS += -fno-strict-aliasing
diff -r fb74347d80c3 extras/mini-os/minios.mk
--- a/extras/mini-os/minios.mk	Wed Mar 05 12:20:40 2008 +0000
+++ b/extras/mini-os/minios.mk	Thu Mar 06 15:57:53 2008 +0000
@@ -15,7 +15,7 @@ DEF_LDFLAGS =
 DEF_LDFLAGS =
 
 ifeq ($(debug),y)
-DEF_CFLAGS += -g
+DEF_CFLAGS += -g -fno-omit-frame-pointer -fno-optimize-sibling-calls
 else
 DEF_CFLAGS += -O3
 endif

Re: [PATCH2] Don't optimize function calls with -g

[Keir Fraser]

Should be in config/StdGNU.mk and config/SunOS.mk. Is optimize-sibling-calls
a gcc option that is supported in all our supported gcc versions? Note that
we do CFLAGS ?= ... in StdGNU.mk and SunOS.mk right now. Probably these
should be changed to +=. That still allows extra CFLAGS to be passed in on
the make command line, but avoids the weird subservience of these
debug-related CFLAG additions.

Whether SunOS should really have different usage of omit-frame-pointer is
open to argument. The Sun guys like to have frame pointers always, and it
seems that is basically a general policy across Solaris binaries, so I let
them have that difference.

 -- Keir

On 6/3/08 16:01, "Samuel Thibault" <samuel.thibault@eu.citrix.com> wrote:

> Samuel Thibault, le Thu 06 Mar 2008 15:55:09 +0000, a écrit :
>> Use -fno-omit-frame-pointer in addition to -g
>> as that permits to use simple stack walk while debugging
> 
> Even better:
> 
> 
> 
> Don't optimize function calls with -g
> -fno-omit-frame-pointer to easily walk the stack
> -fno-optimize-sibling-calls to not miss a step
> 
> Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
> 
> diff -r fb74347d80c3 Config.mk
> --- a/Config.mk Wed Mar 05 12:20:40 2008 +0000
> +++ b/Config.mk Thu Mar 06 15:57:53 2008 +0000
> @@ -55,7 +55,7 @@ endef
>  endef
>  
>  ifeq ($(debug),y)
> -CFLAGS += -g
> +CFLAGS += -g -fno-omit-frame-pointer -fno-optimize-sibling-calls
>  endif
>  
>  CFLAGS += -fno-strict-aliasing
> diff -r fb74347d80c3 extras/mini-os/minios.mk
> --- a/extras/mini-os/minios.mk Wed Mar 05 12:20:40 2008 +0000
> +++ b/extras/mini-os/minios.mk Thu Mar 06 15:57:53 2008 +0000
> @@ -15,7 +15,7 @@ DEF_LDFLAGS =
>  DEF_LDFLAGS =
>  
>  ifeq ($(debug),y)
> -DEF_CFLAGS += -g
> +DEF_CFLAGS += -g -fno-omit-frame-pointer -fno-optimize-sibling-calls
>  else
>  DEF_CFLAGS += -O3
>  endif
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: [PATCH2] Don't optimize function calls with -g

[Samuel Thibault]

Keir Fraser, le Fri 07 Mar 2008 13:36:31 +0000, a écrit :
> Is optimize-sibling-calls a gcc option that is supported in all our
> supported gcc versions?

It is available at least from gcc 3.3

Samuel

[PATCH3] Don't optimize function calls with -g

[Samuel Thibault]

Keir Fraser, le Fri 07 Mar 2008 13:36:31 +0000, a écrit :
> Note that we do CFLAGS ?= ... in StdGNU.mk and SunOS.mk right
> now. Probably these should be changed to +=.

Ooh, that's why I missed the already existing -fno-omit-frame-pointer
there.

> Whether SunOS should really have different usage of omit-frame-pointer is
> open to argument.

Ok, I'll leave it to people who actually run a SunOS system :)



Don't optimize function calls on GNU systems with debug=y
by enforcing the addition of -fno-omit-frame-pointer, and adding
-fno-optimize-sibling-calls.

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

diff -r fb74347d80c3 config/StdGNU.mk
--- a/config/StdGNU.mk	Wed Mar 05 12:20:40 2008 +0000
+++ b/config/StdGNU.mk	Fri Mar 07 14:54:43 2008 +0000
@@ -45,5 +45,5 @@ CFLAGS ?= -O2 -fomit-frame-pointer
 CFLAGS ?= -O2 -fomit-frame-pointer
 else
 # Less than -O1 produces bad code and large stack frames
-CFLAGS ?= -O1 -fno-omit-frame-pointer
+CFLAGS += -O1 -fno-omit-frame-pointer -fno-optimize-sibling-calls
 endif