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From: Nick Desaulniers <ndesaulniers@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <natechancellor@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
	linux-kbuild@vger.kernel.org, linux-arch@vger.kernel.org,
	Jakub Jelinek <jakub@redhat.com>,
	Fangrui Song <maskray@google.com>,
	Caroline Tice <cmtice@google.com>,
	Nick Clifton <nickc@redhat.com>, Yonghong Song <yhs@fb.com>,
	Jiri Olsa <jolsa@kernel.org>, Andrii Nakryiko <andrii@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Arvind Sankar <nivedita@alum.mit.edu>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH v7 1/2] Kbuild: make DWARF version a choice
Date: Fri, 29 Jan 2021 16:44:00 -0800	[thread overview]
Message-ID: <20210130004401.2528717-2-ndesaulniers@google.com> (raw)
In-Reply-To: <20210130004401.2528717-1-ndesaulniers@google.com>

Modifies CONFIG_DEBUG_INFO_DWARF4 to be a member of a choice which is
the default. Does so in a way that's forward compatible with existing
configs, and makes adding future versions more straightforward.

GCC since ~4.8 has defaulted to this DWARF version implicitly.

Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Fangrui Song <maskray@google.com>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
 Makefile          |  5 ++---
 lib/Kconfig.debug | 16 +++++++++++-----
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/Makefile b/Makefile
index 95ab9856f357..d2b4980807e0 100644
--- a/Makefile
+++ b/Makefile
@@ -830,9 +830,8 @@ ifneq ($(LLVM_IAS),1)
 KBUILD_AFLAGS	+= -Wa,-gdwarf-2
 endif
 
-ifdef CONFIG_DEBUG_INFO_DWARF4
-DEBUG_CFLAGS	+= -gdwarf-4
-endif
+dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4
+DEBUG_CFLAGS	+= -gdwarf-$(dwarf-version-y)
 
 ifdef CONFIG_DEBUG_INFO_REDUCED
 DEBUG_CFLAGS	+= $(call cc-option, -femit-struct-debug-baseonly) \
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e906ea906cb7..94c1a7ed6306 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -256,13 +256,19 @@ config DEBUG_INFO_SPLIT
 	  to know about the .dwo files and include them.
 	  Incompatible with older versions of ccache.
 
+choice
+	prompt "DWARF version"
+	help
+	  Which version of DWARF debug info to emit.
+
 config DEBUG_INFO_DWARF4
-	bool "Generate dwarf4 debuginfo"
+	bool "Generate DWARF Version 4 debuginfo"
 	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.
+	  Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
+	  It makes the debug information larger, but it significantly
+	  improves the success of resolving variables in gdb on optimized code.
+
+endchoice # "DWARF version"
 
 config DEBUG_INFO_BTF
 	bool "Generate BTF typeinfo"
-- 
2.30.0.365.g02bc693789-goog


  reply	other threads:[~2021-01-30  1:09 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-30  0:43 [PATCH v7 0/2] Kbuild: DWARF v5 support Nick Desaulniers
2021-01-30  0:44 ` Nick Desaulniers [this message]
2021-01-30  1:52   ` [PATCH v7 1/2] Kbuild: make DWARF version a choice Nathan Chancellor
2021-02-03 22:23     ` Masahiro Yamada
2021-02-03 22:25       ` Masahiro Yamada
2021-02-03 23:16       ` Nick Desaulniers
2021-02-04  0:29         ` Masahiro Yamada
2021-02-04  6:15           ` Nick Desaulniers
2021-02-04  3:32       ` Fangrui Song
2021-02-04  6:08         ` Nick Desaulniers
2021-02-04  6:13     ` Nick Desaulniers
2021-02-04 10:39   ` Mark Wielaard
2021-02-04 19:18     ` Nick Desaulniers
2021-02-04 19:56       ` Mark Wielaard
2021-02-04 20:04         ` Nick Desaulniers
2021-02-04 20:28           ` Mark Wielaard
2021-02-04 22:06             ` Nick Desaulniers
2021-02-04 22:36               ` Fangrui Song
2021-02-05 12:49               ` Mark Wielaard
2021-02-05 21:18                 ` Nick Desaulniers
2021-02-06 15:11                   ` Mark Wielaard
2021-01-30  0:44 ` [PATCH v7 2/2] Kbuild: implement support for DWARF v5 Nick Desaulniers
2021-01-30  1:53   ` Nathan Chancellor
2021-01-30 23:10   ` Sedat Dilek
2021-01-30 23:39     ` Sedat Dilek
2021-01-31  0:37     ` Fāng-ruì Sòng
2021-01-31  0:39       ` Sedat Dilek
2021-02-03 23:06   ` Masahiro Yamada
2021-02-03 23:27     ` Nick Desaulniers
2021-02-04  0:33       ` Masahiro Yamada
2021-02-03 23:36     ` Jakub Jelinek
2021-02-04  0:33       ` Masahiro Yamada
2021-01-30 23:59 ` [PATCH v7 0/2] Kbuild: DWARF v5 support Sedat Dilek

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