Commit d6f4ceb7 authored by Andi Kleen's avatar Andi Kleen Committed by Michal Marek

Kbuild: Add option to set -femit-struct-debug-baseonly

Newer gcc has a -femit-struct-debug-baseonly option that dramatically
reduces the size of object files with debug info. What it does
is to only emit type information for structures when the structures
are defined in the same file or in a header file.

This means the type information for most headers are not included.
This is not good when the type information is actually
needed (e.g. with kgdb or systemtap)

But often kernel hackers only care about line numbers and don't
need all the type information anyways. In this case setting
the option can be a big win:

A build dir for a specific x86-64 configuration with gcc 4.5
shrunk from 2.3G to 1.2G. The compilation was also nearly a minute
faster.
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
[mmarek: reformatted help text]
Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
parent 01ab1788
......@@ -557,6 +557,10 @@ KBUILD_CFLAGS += -g
KBUILD_AFLAGS += -gdwarf-2
endif
ifdef CONFIG_DEBUG_INFO_REDUCED
KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly)
endif
ifdef CONFIG_FUNCTION_TRACER
KBUILD_CFLAGS += -pg
endif
......
......@@ -595,6 +595,19 @@ config DEBUG_INFO
If unsure, say N.
config DEBUG_INFO_REDUCED
bool "Reduce debugging information"
depends on DEBUG_INFO
help
If you say Y here gcc is instructed to generate less debugging
information for structure types. This means that tools that
need full debugging information (like kgdb or systemtap) won't
be happy. But if you merely need debugging information to
resolve line numbers there is no loss. Advantage is that
build directory object sizes shrink dramatically over a full
DEBUG_INFO build and compile times are reduced too.
Only works with newer gcc versions.
config DEBUG_VM
bool "Debug VM"
depends on DEBUG_KERNEL
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment