Remove patch for GCC VTA
It's been years and gcc has changed a lot. Signed-off-by: Laura Abbott <labbott@redhat.com>
This commit is contained in:
Laura Abbott
parent
bde70da19c
commit
3e636fe3a6
@ -1,94 +0,0 @@
|
|||||||
From a446d2f94ce540689c7a46bf457d92409e9c4d7e Mon Sep 17 00:00:00 2001
|
|
||||||
From: Josh Stone <jistone@redhat.com>
|
|
||||||
Date: Fri, 21 Nov 2014 10:40:00 -0800
|
|
||||||
Subject: [PATCH] Kbuild: Add an option to enable GCC VTA
|
|
||||||
MIME-Version: 1.0
|
|
||||||
Content-Type: text/plain; charset=UTF-8
|
|
||||||
Content-Transfer-Encoding: 8bit
|
|
||||||
|
|
||||||
Due to recent codegen issues, gcc -fvar-tracking-assignments was
|
|
||||||
unconditionally disabled in commit 2062afb4f804a ("Fix gcc-4.9.0
|
|
||||||
miscompilation of load_balance() in scheduler"). However, this reduces
|
|
||||||
the debuginfo coverage for variable locations, especially in inline
|
|
||||||
functions. VTA is certainly not perfect either in those cases, but it
|
|
||||||
is much better than without. With compiler versions that have fixed the
|
|
||||||
codegen bugs, we would prefer to have the better details for SystemTap,
|
|
||||||
and surely other debuginfo consumers like perf will benefit as well.
|
|
||||||
|
|
||||||
This patch simply makes CONFIG_DEBUG_INFO_VTA an option. I considered
|
|
||||||
Frank and Linus's discussion of a cc-option-like -fcompare-debug test,
|
|
||||||
but I'm convinced that a narrow test of an arch-specific codegen issue
|
|
||||||
is not really useful. GCC has their own regression tests for this, so
|
|
||||||
I'd suggest GCC_COMPARE_DEBUG=-fvar-tracking-assignments-toggle is more
|
|
||||||
useful for kernel developers to test confidence.
|
|
||||||
|
|
||||||
In fact, I ran into a couple more issues when testing for this patch[1],
|
|
||||||
although neither of those had any codegen impact.
|
|
||||||
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1140872
|
|
||||||
|
|
||||||
With gcc-4.9.2-1.fc22, I can now build v3.18-rc5 with Fedora's i686 and
|
|
||||||
x86_64 configs, and this is completely clean with GCC_COMPARE_DEBUG.
|
|
||||||
|
|
||||||
Cc: Frank Ch. Eigler <fche@redhat.com>
|
|
||||||
Cc: Jakub Jelinek <jakub@redhat.com>
|
|
||||||
Cc: Josh Boyer <jwboyer@fedoraproject.org>
|
|
||||||
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
||||||
Cc: Linus Torvalds <torvalds@linux-foundation.org>
|
|
||||||
Cc: Andrew Morton <akpm@linux-foundation.org>
|
|
||||||
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
|
|
||||||
Cc: Michel Dänzer <michel@daenzer.net>
|
|
||||||
Signed-off-by: Josh Stone <jistone@redhat.com>
|
|
||||||
Signed-off-by: Jeremy Cline <jcline@redhat.com>
|
|
||||||
---
|
|
||||||
Makefile | 4 ++++
|
|
||||||
lib/Kconfig.debug | 18 +++++++++++++++++-
|
|
||||||
2 files changed, 21 insertions(+), 1 deletion(-)
|
|
||||||
|
|
||||||
diff --git a/Makefile b/Makefile
|
|
||||||
index 9ef547fc7ffe..5777d902f8f3 100644
|
|
||||||
--- a/Makefile
|
|
||||||
+++ b/Makefile
|
|
||||||
@@ -735,7 +735,11 @@ KBUILD_CFLAGS += -fomit-frame-pointer
|
|
||||||
KBUILD_CFLAGS += -ftrivial-auto-var-init=pattern
|
|
||||||
endif
|
|
||||||
|
|
||||||
+ifdef CONFIG_DEBUG_INFO_VTA
|
|
||||||
+DEBUG_CFLAGS += $(call cc-option, -fvar-tracking-assignments)
|
|
||||||
+else
|
|
||||||
DEBUG_CFLAGS := $(call cc-option, -fno-var-tracking-assignments)
|
|
||||||
+endif
|
|
||||||
|
|
||||||
ifdef CONFIG_DEBUG_INFO
|
|
||||||
ifdef CONFIG_DEBUG_INFO_SPLIT
|
|
||||||
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
|
|
||||||
index 0d9e81779e37..424206212931 100644
|
|
||||||
--- a/lib/Kconfig.debug
|
|
||||||
+++ b/lib/Kconfig.debug
|
|
||||||
@@ -217,7 +217,23 @@ config DEBUG_INFO_DWARF4
|
|
||||||
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.
|
|
||||||
+ variables in gdb on optimized code. The gcc docs also
|
|
||||||
+ recommend enabling -fvar-tracking-assignments for maximum
|
|
||||||
+ benefit. (see DEBUG_INFO_VTA)
|
|
||||||
+
|
|
||||||
+config DEBUG_INFO_VTA
|
|
||||||
+ bool "Enable var-tracking-assignments for debuginfo"
|
|
||||||
+ depends on DEBUG_INFO
|
|
||||||
+ help
|
|
||||||
+ Enable gcc -fvar-tracking-assignments for improved debug
|
|
||||||
+ information on variable locations in optimized code. Per
|
|
||||||
+ gcc, DEBUG_INFO_DWARF4 is recommended for best use of VTA.
|
|
||||||
+
|
|
||||||
+ VTA has been implicated in codegen bugs (gcc PR61801,
|
|
||||||
+ PR61904), so this may deserve some caution. One can set
|
|
||||||
+ GCC_COMPARE_DEBUG=-fvar-tracking-assignments-toggle in the
|
|
||||||
+ environment to automatically compile everything both ways,
|
|
||||||
+ generating an error if anything differs.
|
|
||||||
|
|
||||||
config DEBUG_INFO_BTF
|
|
||||||
bool "Generate BTF typeinfo"
|
|
||||||
--
|
|
||||||
2.20.1
|
|
||||||
|
|
||||||
@ -495,8 +495,6 @@ Source5000: patch-5.%{base_sublevel}-git%{gitrev}.xz
|
|||||||
# Standalone patches
|
# Standalone patches
|
||||||
# 100 - Generic long running patches
|
# 100 - Generic long running patches
|
||||||
|
|
||||||
Patch115: Kbuild-Add-an-option-to-enable-GCC-VTA.patch
|
|
||||||
|
|
||||||
Patch116: crash-driver.patch
|
Patch116: crash-driver.patch
|
||||||
|
|
||||||
Patch122: Input-synaptics-pin-3-touches-when-the-firmware-repo.patch
|
Patch122: Input-synaptics-pin-3-touches-when-the-firmware-repo.patch
|
||||||
|
|||||||
Loading…
Reference in New Issue
Block a user