[PATCH dwarves] btf: Add --btf_gen_all flag

From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Arnaldo Carvalho de Melo <acme@redhat.com>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: dwarves@vger.kernel.org, bpf@vger.kernel.org,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Yonghong Song <yhs@fb.com>, Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH dwarves] btf: Add --btf_gen_all flag
Date: Fri, 12 Mar 2021 01:08:08 +0100	[thread overview]
Message-ID: <20210312000808.175262-1-iii@linux.ibm.com> (raw)

By default, pahole makes use only of BTF features introduced with
kernel v5.2. Features that are added later need to be turned on with
explicit feature flags, such as --btf_gen_floats. According to [1],
this will hinder the people who generate BTF for kernels externally
(e.g. for old kernels to support BPF CO-RE).

Introduce --btf_gen_all that allows using all BTF features supported
by pahole.

[1] https://lore.kernel.org/dwarves/CAEf4Bzbyugfb2RkBkRuxNGKwSk40Tbq4zAvhQT8W=fVMYWuaxA@mail.gmail.com/

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 man-pages/pahole.1 | 4 ++++
 pahole.c           | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/man-pages/pahole.1 b/man-pages/pahole.1
index e292b2c..cbbefbf 100644
--- a/man-pages/pahole.1
+++ b/man-pages/pahole.1
@@ -204,6 +204,10 @@ to "/sys/kernel/btf/vmlinux".
 Allow producing BTF_KIND_FLOAT entries in systems where the vmlinux DWARF
 information has float types.
 
+.TP
+.B \-\-btf_gen_all
+Allow using all the BTF features supported by pahole.
+
 .TP
 .B \-l, \-\-show_first_biggest_size_base_type_member
 Show first biggest size base_type member.
diff --git a/pahole.c b/pahole.c
index c8d38f5..df6aa83 100644
--- a/pahole.c
+++ b/pahole.c
@@ -826,6 +826,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;
 #define ARGP_numeric_version       320
 #define ARGP_btf_base		   321
 #define ARGP_btf_gen_floats	   322
+#define ARGP_btf_gen_all	   323
 
 static const struct argp_option pahole__options[] = {
 	{
@@ -1125,6 +1126,11 @@ static const struct argp_option pahole__options[] = {
 		.key  = ARGP_btf_gen_floats,
 		.doc  = "Allow producing BTF_KIND_FLOAT entries."
 	},
+	{
+		.name = "btf_gen_all",
+		.key  = ARGP_btf_gen_all,
+		.doc  = "Allow using all the BTF features supported by pahole."
+	},
 	{
 		.name = "structs",
 		.key  = ARGP_just_structs,
@@ -1262,6 +1268,8 @@ static error_t pahole__options_parser(int key, char *arg,
 		print_numeric_version = true;		break;
 	case ARGP_btf_gen_floats:
 		btf_gen_floats = true;			break;
+	case ARGP_btf_gen_all:
+		btf_gen_floats = true;			break;
 	default:
 		return ARGP_ERR_UNKNOWN;
 	}
-- 
2.29.2

