diff mbox

[2/2] Kbuild: Add a option to enable dwarf4 v2

Message ID 1406746219-15427-2-git-send-email-andi@firstfloor.org (mailing list archive)
State New, archived
Headers show

Commit Message

Andi Kleen July 30, 2014, 6:50 p.m. UTC 
From: Andi Kleen <ak@linux.intel.com>

I found that a lot of unresolvable variables when using gdb on the kernel
become resolvable when dwarf4 is enabled. So add a Kconfig flag to enable it.

It definitely increases the debug information size, but on the other
hand this isn't so bad when debug fusion is used.

v2: Use cc-option
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 Makefile          | 3 +++
 lib/Kconfig.debug | 9 +++++++++
 2 files changed, 12 insertions(+)

Comments

Sam Ravnborg July 30, 2014, 7 p.m. UTC | #1 
On Wed, Jul 30, 2014 at 08:50:19PM +0200, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> I found that a lot of unresolvable variables when using gdb on the kernel
> become resolvable when dwarf4 is enabled. So add a Kconfig flag to enable it.
> 
> It definitely increases the debug information size, but on the other
> hand this isn't so bad when debug fusion is used.
> 
> v2: Use cc-option
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
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diff mbox

Patch

diff --git a/Makefile b/Makefile
index 6a717cd..fd76983 100644
--- a/Makefile
+++ b/Makefile
@@ -696,6 +696,9 @@  KBUILD_CFLAGS	+= -g
 endif
 KBUILD_AFLAGS	+= -Wa,-gdwarf-2
 endif
+ifdef CONFIG_DEBUG_INFO_DWARF4
+KBUILD_CFLAGS	+= $(call cc-option, -gdwarf-4,)
+endif
 
 ifdef CONFIG_DEBUG_INFO_REDUCED
 KBUILD_CFLAGS 	+= $(call cc-option, -femit-struct-debug-baseonly) \
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 0360468..a2dcf97 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -158,6 +158,15 @@  config DEBUG_INFO_SPLIT
 	  to know about the .dwo files and include them.
 	  Incompatible with older versions of ccache.
 
+config DEBUG_INFO_DWARF4
+	bool "Generate dwarf4 debuginfo"
+	depends on DEBUG_INFO
+	help
+	  Generate dwarf4 debug info. This requires recent versions
+	  of gcc and gdb. It makes the debug information larger.
+	  But it significantly improves the success of resolving
+	  variables in gdb on optimized code.
+
 config ENABLE_WARN_DEPRECATED
 	bool "Enable __deprecated logic"
 	default y