2:57 p.m.
It's been years and gcc has changed a lot.
Signed-off-by: Laura Abbott <labbott(a)redhat.com>
---
Kbuild-Add-an-option-to-enable-GCC-VTA.patch | 94 --------------------
kernel.spec | 2 -
2 files changed, 96 deletions(-)
delete mode 100644 Kbuild-Add-an-option-to-enable-GCC-VTA.patch
diff --git a/Kbuild-Add-an-option-to-enable-GCC-VTA.patch
b/Kbuild-Add-an-option-to-enable-GCC-VTA.patch
deleted file mode 100644
index 6bbb0efdf..000000000
--- a/Kbuild-Add-an-option-to-enable-GCC-VTA.patch
+++ /dev/null
@@ -1,94 +0,0 @@
-From a446d2f94ce540689c7a46bf457d92409e9c4d7e Mon Sep 17 00:00:00 2001
-From: Josh Stone <jistone(a)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(a)redhat.com>
-Cc: Jakub Jelinek <jakub(a)redhat.com>
-Cc: Josh Boyer <jwboyer(a)fedoraproject.org>
-Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
-Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
-Cc: Andrew Morton <akpm(a)linux-foundation.org>
-Cc: Markus Trippelsdorf <markus(a)trippelsdorf.de>
-Cc: Michel Dänzer <michel(a)daenzer.net>
-Signed-off-by: Josh Stone <jistone(a)redhat.com>
-Signed-off-by: Jeremy Cline <jcline(a)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
-
diff --git a/kernel.spec b/kernel.spec
index e7e73d104..c91483f3d 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -495,8 +495,6 @@ Source5000: patch-5.%{base_sublevel}-git%{gitrev}.xz
# Standalone patches
# 100 - Generic long running patches
-Patch115: Kbuild-Add-an-option-to-enable-GCC-VTA.patch
-
Patch116: crash-driver.patch
Patch122: Input-synaptics-pin-3-touches-when-the-firmware-repo.patch
--
2.21.0