diff mbox series

[bpf-next,v2,3/5] bpftool: Support inline annotations when dumping the CFG of a program

Message ID 20230327110655.58363-4-quentin@isovalent.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpftool: Add inline annotations when dumping program CFGs | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 20 this patch: 20
netdev/cc_maintainers warning 2 maintainers not CCed: martin.lau@linux.dev song@kernel.org
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 203 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
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Commit Message

Quentin Monnet March 27, 2023, 11:06 a.m. UTC
We support dumping the control flow graph of loaded programs to the DOT
format with bpftool, but so far this feature wouldn't display the source
code lines available through BTF along with the eBPF bytecode. Let's add
support for these annotations, to make it easier to read the graph.

In prog.c, we move the call to dump_xlated_cfg() in order to pass and
use the full struct dump_data, instead of creating a minimal one in
draw_bb_node().

We pass the pointer to this struct down to dump_xlated_for_graph() in
xlated_dumper.c, where most of the logics is added. We deal with BTF
mostly like we do for plain or JSON output, except that we cannot use a
"nr_skip" value to skip a given number of linfo records (we don't
process the BPF instructions linearly, and apart from the root of the
graph we don't know how many records we should skip, so we just store
the last linfo and make sure the new one we find is different before
printing it).

When printing the source instructions to the label of a DOT graph node,
there are a few subtleties to address. We want some special newline
markers, and there are some characters that we must escape. To deal with
them, we introduce a new dedicated function btf_dump_linfo_dotlabel() in
btf_dumper.c. We'll reuse this function in a later commit to format the
filepath, line, and column references as well.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
---
 tools/bpf/bpftool/btf_dumper.c    | 32 +++++++++++++++++++++++++++++++
 tools/bpf/bpftool/cfg.c           | 23 ++++++++++------------
 tools/bpf/bpftool/cfg.h           |  4 +++-
 tools/bpf/bpftool/main.h          |  2 ++
 tools/bpf/bpftool/prog.c          | 17 +++++++---------
 tools/bpf/bpftool/xlated_dumper.c | 32 ++++++++++++++++++++++++++++++-
 6 files changed, 85 insertions(+), 25 deletions(-)

Comments

Eduard Zingerman March 27, 2023, 5:02 p.m. UTC | #1
On Mon, 2023-03-27 at 12:06 +0100, Quentin Monnet wrote:
> We support dumping the control flow graph of loaded programs to the DOT
> format with bpftool, but so far this feature wouldn't display the source
> code lines available through BTF along with the eBPF bytecode. Let's add
> support for these annotations, to make it easier to read the graph.
> 
> In prog.c, we move the call to dump_xlated_cfg() in order to pass and
> use the full struct dump_data, instead of creating a minimal one in
> draw_bb_node().
> 
> We pass the pointer to this struct down to dump_xlated_for_graph() in
> xlated_dumper.c, where most of the logics is added. We deal with BTF
> mostly like we do for plain or JSON output, except that we cannot use a
> "nr_skip" value to skip a given number of linfo records (we don't
> process the BPF instructions linearly, and apart from the root of the
> graph we don't know how many records we should skip, so we just store
> the last linfo and make sure the new one we find is different before
> printing it).
> 
> When printing the source instructions to the label of a DOT graph node,
> there are a few subtleties to address. We want some special newline
> markers, and there are some characters that we must escape. To deal with
> them, we introduce a new dedicated function btf_dump_linfo_dotlabel() in
> btf_dumper.c. We'll reuse this function in a later commit to format the
> filepath, line, and column references as well.
> 
> Signed-off-by: Quentin Monnet <quentin@isovalent.com>
> Acked-by: Stanislav Fomichev <sdf@google.com>
> ---
>  tools/bpf/bpftool/btf_dumper.c    | 32 +++++++++++++++++++++++++++++++
>  tools/bpf/bpftool/cfg.c           | 23 ++++++++++------------
>  tools/bpf/bpftool/cfg.h           |  4 +++-
>  tools/bpf/bpftool/main.h          |  2 ++
>  tools/bpf/bpftool/prog.c          | 17 +++++++---------
>  tools/bpf/bpftool/xlated_dumper.c | 32 ++++++++++++++++++++++++++++++-
>  6 files changed, 85 insertions(+), 25 deletions(-)
> 
> diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
> index e7f6ec3a8f35..8bfc1b69497d 100644
> --- a/tools/bpf/bpftool/btf_dumper.c
> +++ b/tools/bpf/bpftool/btf_dumper.c
> @@ -821,3 +821,35 @@ void btf_dump_linfo_json(const struct btf *btf,
>  					BPF_LINE_INFO_LINE_COL(linfo->line_col));
>  	}
>  }
> +
> +static void dotlabel_puts(const char *s)
> +{
> +	for (; *s; ++s) {
> +		switch (*s) {
> +		case '\\':
> +		case '"':
> +		case '{':
> +		case '}':
> +		case '>':

The "case '<':" is missing, w/o it dot reports warnings as follows:

  Error: bad label format {; if (hdr + hdr_size <= data_end)...

I used existing bpt testcase for testing:

  $ cd <kernel>/tools/testing/selftests/bpf
  $ bpftool prog load bpf_flow.bpf.o /sys/fs/bpf/test-prog
  $ prog dump xlated pinned /sys/fs/bpf/test-prog visual > test.cfg
  $ dot -Tpng -O test.cfg
  
Also [1] says the following:

> Braces, vertical bars and angle brackets must be escaped with a
> backslash character if you wish them to appear as a literal
> character. Spaces are interpreted as separators between tokens, so
> they must be escaped if you want spaces in the text.

So, maybe escape spaces as well?

[1] https://graphviz.org/doc/info/shapes.html#record

> +		case '|':
> +			putchar('\\');
> +			__fallthrough;
> +		default:
> +			putchar(*s);
> +		}
> +	}
> +}
> +
> +void btf_dump_linfo_dotlabel(const struct btf *btf,
> +			     const struct bpf_line_info *linfo)
> +{
> +	const char *line = btf__name_by_offset(btf, linfo->line_off);
> +
> +	if (!line)
> +		return;
> +	line = ltrim(line);
> +
> +	printf("; ");
> +	dotlabel_puts(line);
> +	printf("\\l\\\n");
> +}
> diff --git a/tools/bpf/bpftool/cfg.c b/tools/bpf/bpftool/cfg.c
> index 1951219a9af7..9fdc1f0cdd6e 100644
> --- a/tools/bpf/bpftool/cfg.c
> +++ b/tools/bpf/bpftool/cfg.c
> @@ -380,7 +380,8 @@ static void cfg_destroy(struct cfg *cfg)
>  	}
>  }
>  
> -static void draw_bb_node(struct func_node *func, struct bb_node *bb)
> +static void
> +draw_bb_node(struct func_node *func, struct bb_node *bb, struct dump_data *dd)
>  {
>  	const char *shape;
>  
> @@ -398,13 +399,9 @@ static void draw_bb_node(struct func_node *func, struct bb_node *bb)
>  		printf("EXIT");
>  	} else {
>  		unsigned int start_idx;
> -		struct dump_data dd = {};
> -
> -		printf("{");
> -		kernel_syms_load(&dd);
> +		printf("{\\\n");
>  		start_idx = bb->head - func->start;
> -		dump_xlated_for_graph(&dd, bb->head, bb->tail, start_idx);
> -		kernel_syms_destroy(&dd);
> +		dump_xlated_for_graph(dd, bb->head, bb->tail, start_idx);
>  		printf("}");
>  	}
>  
> @@ -430,12 +427,12 @@ static void draw_bb_succ_edges(struct func_node *func, struct bb_node *bb)
>  	}
>  }
>  
> -static void func_output_bb_def(struct func_node *func)
> +static void func_output_bb_def(struct func_node *func, struct dump_data *dd)
>  {
>  	struct bb_node *bb;
>  
>  	list_for_each_entry(bb, &func->bbs, l) {
> -		draw_bb_node(func, bb);
> +		draw_bb_node(func, bb, dd);
>  	}
>  }
>  
> @@ -455,7 +452,7 @@ static void func_output_edges(struct func_node *func)
>  	       func_idx, ENTRY_BLOCK_INDEX, func_idx, EXIT_BLOCK_INDEX);
>  }
>  
> -static void cfg_dump(struct cfg *cfg)
> +static void cfg_dump(struct cfg *cfg, struct dump_data *dd)
>  {
>  	struct func_node *func;
>  
> @@ -463,14 +460,14 @@ static void cfg_dump(struct cfg *cfg)
>  	list_for_each_entry(func, &cfg->funcs, l) {
>  		printf("subgraph \"cluster_%d\" {\n\tstyle=\"dashed\";\n\tcolor=\"black\";\n\tlabel=\"func_%d ()\";\n",
>  		       func->idx, func->idx);
> -		func_output_bb_def(func);
> +		func_output_bb_def(func, dd);
>  		func_output_edges(func);
>  		printf("}\n");
>  	}
>  	printf("}\n");
>  }
>  
> -void dump_xlated_cfg(void *buf, unsigned int len)
> +void dump_xlated_cfg(struct dump_data *dd, void *buf, unsigned int len)
>  {
>  	struct bpf_insn *insn = buf;
>  	struct cfg cfg;
> @@ -479,7 +476,7 @@ void dump_xlated_cfg(void *buf, unsigned int len)
>  	if (cfg_build(&cfg, insn, len))
>  		return;
>  
> -	cfg_dump(&cfg);
> +	cfg_dump(&cfg, dd);
>  
>  	cfg_destroy(&cfg);
>  }
> diff --git a/tools/bpf/bpftool/cfg.h b/tools/bpf/bpftool/cfg.h
> index e144257ea6d2..909d17e6d4c2 100644
> --- a/tools/bpf/bpftool/cfg.h
> +++ b/tools/bpf/bpftool/cfg.h
> @@ -4,6 +4,8 @@
>  #ifndef __BPF_TOOL_CFG_H
>  #define __BPF_TOOL_CFG_H
>  
> -void dump_xlated_cfg(void *buf, unsigned int len);
> +#include "xlated_dumper.h"
> +
> +void dump_xlated_cfg(struct dump_data *dd, void *buf, unsigned int len);
>  
>  #endif /* __BPF_TOOL_CFG_H */
> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
> index 0ef373cef4c7..e9ee514b22d4 100644
> --- a/tools/bpf/bpftool/main.h
> +++ b/tools/bpf/bpftool/main.h
> @@ -229,6 +229,8 @@ void btf_dump_linfo_plain(const struct btf *btf,
>  			  const char *prefix, bool linum);
>  void btf_dump_linfo_json(const struct btf *btf,
>  			 const struct bpf_line_info *linfo, bool linum);
> +void btf_dump_linfo_dotlabel(const struct btf *btf,
> +			     const struct bpf_line_info *linfo);
>  
>  struct nlattr;
>  struct ifinfomsg;
> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index afbe3ec342c8..d855118f0d96 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -840,11 +840,6 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
>  					      false))
>  				goto exit_free;
>  		}
> -	} else if (visual) {
> -		if (json_output)
> -			jsonw_null(json_wtr);
> -		else
> -			dump_xlated_cfg(buf, member_len);
>  	} else {
>  		kernel_syms_load(&dd);
>  		dd.nr_jited_ksyms = info->nr_jited_ksyms;
> @@ -854,12 +849,14 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
>  		dd.finfo_rec_size = info->func_info_rec_size;
>  		dd.prog_linfo = prog_linfo;
>  
> -		if (json_output)
> -			dump_xlated_json(&dd, buf, member_len, opcodes,
> -					 linum);
> +		if (json_output && visual)
> +			jsonw_null(json_wtr);

Should this be an error? Maybe check that json_output is false when
arguments are parsed and 'visual' is specified?

> +		else if (json_output)
> +			dump_xlated_json(&dd, buf, member_len, opcodes, linum);
> +		else if (visual)
> +			dump_xlated_cfg(&dd, buf, member_len);
>  		else
> -			dump_xlated_plain(&dd, buf, member_len, opcodes,
> -					  linum);
> +			dump_xlated_plain(&dd, buf, member_len, opcodes, linum);
>  		kernel_syms_destroy(&dd);
>  	}
>  
> diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
> index 3daa05d9bbb7..5fbe94aa8589 100644
> --- a/tools/bpf/bpftool/xlated_dumper.c
> +++ b/tools/bpf/bpftool/xlated_dumper.c
> @@ -369,20 +369,50 @@ void dump_xlated_for_graph(struct dump_data *dd, void *buf_start, void *buf_end,
>  		.cb_imm		= print_imm,
>  		.private_data	= dd,
>  	};
> +	const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
> +	const struct bpf_line_info *last_linfo = NULL;
> +	struct bpf_func_info *record = dd->func_info;
>  	struct bpf_insn *insn_start = buf_start;
>  	struct bpf_insn *insn_end = buf_end;
>  	struct bpf_insn *cur = insn_start;
> +	struct btf *btf = dd->btf;
>  	bool double_insn = false;
> +	char func_sig[1024];
>  
>  	for (; cur <= insn_end; cur++) {
> +		unsigned int insn_off;
> +
>  		if (double_insn) {
>  			double_insn = false;
>  			continue;
>  		}
>  		double_insn = cur->code == (BPF_LD | BPF_IMM | BPF_DW);
>  
> -		printf("% 4d: ", (int)(cur - insn_start + start_idx));
> +		insn_off = (unsigned int)(cur - insn_start + start_idx);
> +		if (btf && record) {
> +			if (record->insn_off == insn_off) {
> +				btf_dumper_type_only(btf, record->type_id,
> +						     func_sig,
> +						     sizeof(func_sig));
> +				if (func_sig[0] != '\0')
> +					printf("; %s:\\l\\\n", func_sig);
> +				record = (void *)record + dd->finfo_rec_size;
> +			}
> +		}
> +
> +		if (prog_linfo) {
> +			const struct bpf_line_info *linfo;
> +
> +			linfo = bpf_prog_linfo__lfind(prog_linfo, insn_off, 0);
> +			if (linfo && linfo != last_linfo) {
> +				btf_dump_linfo_dotlabel(btf, linfo);
> +				last_linfo = linfo;
> +			}
> +		}
> +
> +		printf("%d: ", insn_off);
>  		print_bpf_insn(&cbs, cur, true);
> +
>  		if (cur != insn_end)
>  			printf(" | ");
>  	}
Quentin Monnet March 31, 2023, 2:52 p.m. UTC | #2
Hi Eduard, apologies for the slow answer

2023-03-27 20:02 UTC+0300 ~ Eduard Zingerman <eddyz87@gmail.com>
> On Mon, 2023-03-27 at 12:06 +0100, Quentin Monnet wrote:
>> We support dumping the control flow graph of loaded programs to the DOT
>> format with bpftool, but so far this feature wouldn't display the source
>> code lines available through BTF along with the eBPF bytecode. Let's add
>> support for these annotations, to make it easier to read the graph.
>>
>> In prog.c, we move the call to dump_xlated_cfg() in order to pass and
>> use the full struct dump_data, instead of creating a minimal one in
>> draw_bb_node().
>>
>> We pass the pointer to this struct down to dump_xlated_for_graph() in
>> xlated_dumper.c, where most of the logics is added. We deal with BTF
>> mostly like we do for plain or JSON output, except that we cannot use a
>> "nr_skip" value to skip a given number of linfo records (we don't
>> process the BPF instructions linearly, and apart from the root of the
>> graph we don't know how many records we should skip, so we just store
>> the last linfo and make sure the new one we find is different before
>> printing it).
>>
>> When printing the source instructions to the label of a DOT graph node,
>> there are a few subtleties to address. We want some special newline
>> markers, and there are some characters that we must escape. To deal with
>> them, we introduce a new dedicated function btf_dump_linfo_dotlabel() in
>> btf_dumper.c. We'll reuse this function in a later commit to format the
>> filepath, line, and column references as well.
>>
>> Signed-off-by: Quentin Monnet <quentin@isovalent.com>
>> Acked-by: Stanislav Fomichev <sdf@google.com>
>> ---
>>  tools/bpf/bpftool/btf_dumper.c    | 32 +++++++++++++++++++++++++++++++
>>  tools/bpf/bpftool/cfg.c           | 23 ++++++++++------------
>>  tools/bpf/bpftool/cfg.h           |  4 +++-
>>  tools/bpf/bpftool/main.h          |  2 ++
>>  tools/bpf/bpftool/prog.c          | 17 +++++++---------
>>  tools/bpf/bpftool/xlated_dumper.c | 32 ++++++++++++++++++++++++++++++-
>>  6 files changed, 85 insertions(+), 25 deletions(-)
>>
>> diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
>> index e7f6ec3a8f35..8bfc1b69497d 100644
>> --- a/tools/bpf/bpftool/btf_dumper.c
>> +++ b/tools/bpf/bpftool/btf_dumper.c
>> @@ -821,3 +821,35 @@ void btf_dump_linfo_json(const struct btf *btf,
>>  					BPF_LINE_INFO_LINE_COL(linfo->line_col));
>>  	}
>>  }
>> +
>> +static void dotlabel_puts(const char *s)
>> +{
>> +	for (; *s; ++s) {
>> +		switch (*s) {
>> +		case '\\':
>> +		case '"':
>> +		case '{':
>> +		case '}':
>> +		case '>':
> 
> The "case '<':" is missing, w/o it dot reports warnings as follows:
> 
>   Error: bad label format {; if (hdr + hdr_size <= data_end)...

Good catch, thank you!

> 
> I used existing bpt testcase for testing:
> 
>   $ cd <kernel>/tools/testing/selftests/bpf
>   $ bpftool prog load bpf_flow.bpf.o /sys/fs/bpf/test-prog
>   $ prog dump xlated pinned /sys/fs/bpf/test-prog visual > test.cfg
>   $ dot -Tpng -O test.cfg
>   
> Also [1] says the following:
> 
>> Braces, vertical bars and angle brackets must be escaped with a
>> backslash character if you wish them to appear as a literal
>> character. Spaces are interpreted as separators between tokens, so
>> they must be escaped if you want spaces in the text.
> 
> So, maybe escape spaces as well?
> 
> [1] https://graphviz.org/doc/info/shapes.html#record

I hesitated a little, because we risk getting a wider output if we
preserve spaces. But it's maybe better to preserve the initial line
rather than to decide we can get rid of sequences with multiple
spaces... OK I'll escape them, too.

> 
>> +		case '|':
>> +			putchar('\\');
>> +			__fallthrough;
>> +		default:
>> +			putchar(*s);
>> +		}
>> +	}
>> +}
>> +
>> +void btf_dump_linfo_dotlabel(const struct btf *btf,
>> +			     const struct bpf_line_info *linfo)
>> +{
>> +	const char *line = btf__name_by_offset(btf, linfo->line_off);
>> +
>> +	if (!line)
>> +		return;
>> +	line = ltrim(line);
>> +
>> +	printf("; ");
>> +	dotlabel_puts(line);
>> +	printf("\\l\\\n");
>> +}
>> diff --git a/tools/bpf/bpftool/cfg.c b/tools/bpf/bpftool/cfg.c
>> index 1951219a9af7..9fdc1f0cdd6e 100644
>> --- a/tools/bpf/bpftool/cfg.c
>> +++ b/tools/bpf/bpftool/cfg.c
>> @@ -380,7 +380,8 @@ static void cfg_destroy(struct cfg *cfg)
>>  	}
>>  }
>>  
>> -static void draw_bb_node(struct func_node *func, struct bb_node *bb)
>> +static void
>> +draw_bb_node(struct func_node *func, struct bb_node *bb, struct dump_data *dd)
>>  {
>>  	const char *shape;
>>  
>> @@ -398,13 +399,9 @@ static void draw_bb_node(struct func_node *func, struct bb_node *bb)
>>  		printf("EXIT");
>>  	} else {
>>  		unsigned int start_idx;
>> -		struct dump_data dd = {};
>> -
>> -		printf("{");
>> -		kernel_syms_load(&dd);
>> +		printf("{\\\n");
>>  		start_idx = bb->head - func->start;
>> -		dump_xlated_for_graph(&dd, bb->head, bb->tail, start_idx);
>> -		kernel_syms_destroy(&dd);
>> +		dump_xlated_for_graph(dd, bb->head, bb->tail, start_idx);
>>  		printf("}");
>>  	}
>>  
>> @@ -430,12 +427,12 @@ static void draw_bb_succ_edges(struct func_node *func, struct bb_node *bb)
>>  	}
>>  }
>>  
>> -static void func_output_bb_def(struct func_node *func)
>> +static void func_output_bb_def(struct func_node *func, struct dump_data *dd)
>>  {
>>  	struct bb_node *bb;
>>  
>>  	list_for_each_entry(bb, &func->bbs, l) {
>> -		draw_bb_node(func, bb);
>> +		draw_bb_node(func, bb, dd);
>>  	}
>>  }
>>  
>> @@ -455,7 +452,7 @@ static void func_output_edges(struct func_node *func)
>>  	       func_idx, ENTRY_BLOCK_INDEX, func_idx, EXIT_BLOCK_INDEX);
>>  }
>>  
>> -static void cfg_dump(struct cfg *cfg)
>> +static void cfg_dump(struct cfg *cfg, struct dump_data *dd)
>>  {
>>  	struct func_node *func;
>>  
>> @@ -463,14 +460,14 @@ static void cfg_dump(struct cfg *cfg)
>>  	list_for_each_entry(func, &cfg->funcs, l) {
>>  		printf("subgraph \"cluster_%d\" {\n\tstyle=\"dashed\";\n\tcolor=\"black\";\n\tlabel=\"func_%d ()\";\n",
>>  		       func->idx, func->idx);
>> -		func_output_bb_def(func);
>> +		func_output_bb_def(func, dd);
>>  		func_output_edges(func);
>>  		printf("}\n");
>>  	}
>>  	printf("}\n");
>>  }
>>  
>> -void dump_xlated_cfg(void *buf, unsigned int len)
>> +void dump_xlated_cfg(struct dump_data *dd, void *buf, unsigned int len)
>>  {
>>  	struct bpf_insn *insn = buf;
>>  	struct cfg cfg;
>> @@ -479,7 +476,7 @@ void dump_xlated_cfg(void *buf, unsigned int len)
>>  	if (cfg_build(&cfg, insn, len))
>>  		return;
>>  
>> -	cfg_dump(&cfg);
>> +	cfg_dump(&cfg, dd);
>>  
>>  	cfg_destroy(&cfg);
>>  }
>> diff --git a/tools/bpf/bpftool/cfg.h b/tools/bpf/bpftool/cfg.h
>> index e144257ea6d2..909d17e6d4c2 100644
>> --- a/tools/bpf/bpftool/cfg.h
>> +++ b/tools/bpf/bpftool/cfg.h
>> @@ -4,6 +4,8 @@
>>  #ifndef __BPF_TOOL_CFG_H
>>  #define __BPF_TOOL_CFG_H
>>  
>> -void dump_xlated_cfg(void *buf, unsigned int len);
>> +#include "xlated_dumper.h"
>> +
>> +void dump_xlated_cfg(struct dump_data *dd, void *buf, unsigned int len);
>>  
>>  #endif /* __BPF_TOOL_CFG_H */
>> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
>> index 0ef373cef4c7..e9ee514b22d4 100644
>> --- a/tools/bpf/bpftool/main.h
>> +++ b/tools/bpf/bpftool/main.h
>> @@ -229,6 +229,8 @@ void btf_dump_linfo_plain(const struct btf *btf,
>>  			  const char *prefix, bool linum);
>>  void btf_dump_linfo_json(const struct btf *btf,
>>  			 const struct bpf_line_info *linfo, bool linum);
>> +void btf_dump_linfo_dotlabel(const struct btf *btf,
>> +			     const struct bpf_line_info *linfo);
>>  
>>  struct nlattr;
>>  struct ifinfomsg;
>> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
>> index afbe3ec342c8..d855118f0d96 100644
>> --- a/tools/bpf/bpftool/prog.c
>> +++ b/tools/bpf/bpftool/prog.c
>> @@ -840,11 +840,6 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
>>  					      false))
>>  				goto exit_free;
>>  		}
>> -	} else if (visual) {
>> -		if (json_output)
>> -			jsonw_null(json_wtr);
>> -		else
>> -			dump_xlated_cfg(buf, member_len);
>>  	} else {
>>  		kernel_syms_load(&dd);
>>  		dd.nr_jited_ksyms = info->nr_jited_ksyms;
>> @@ -854,12 +849,14 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
>>  		dd.finfo_rec_size = info->func_info_rec_size;
>>  		dd.prog_linfo = prog_linfo;
>>  
>> -		if (json_output)
>> -			dump_xlated_json(&dd, buf, member_len, opcodes,
>> -					 linum);
>> +		if (json_output && visual)
>> +			jsonw_null(json_wtr);
> 
> Should this be an error? Maybe check that json_output is false when
> arguments are parsed and 'visual' is specified?

Right, makes sense to turn this into an error.
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index e7f6ec3a8f35..8bfc1b69497d 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -821,3 +821,35 @@  void btf_dump_linfo_json(const struct btf *btf,
 					BPF_LINE_INFO_LINE_COL(linfo->line_col));
 	}
 }
+
+static void dotlabel_puts(const char *s)
+{
+	for (; *s; ++s) {
+		switch (*s) {
+		case '\\':
+		case '"':
+		case '{':
+		case '}':
+		case '>':
+		case '|':
+			putchar('\\');
+			__fallthrough;
+		default:
+			putchar(*s);
+		}
+	}
+}
+
+void btf_dump_linfo_dotlabel(const struct btf *btf,
+			     const struct bpf_line_info *linfo)
+{
+	const char *line = btf__name_by_offset(btf, linfo->line_off);
+
+	if (!line)
+		return;
+	line = ltrim(line);
+
+	printf("; ");
+	dotlabel_puts(line);
+	printf("\\l\\\n");
+}
diff --git a/tools/bpf/bpftool/cfg.c b/tools/bpf/bpftool/cfg.c
index 1951219a9af7..9fdc1f0cdd6e 100644
--- a/tools/bpf/bpftool/cfg.c
+++ b/tools/bpf/bpftool/cfg.c
@@ -380,7 +380,8 @@  static void cfg_destroy(struct cfg *cfg)
 	}
 }
 
-static void draw_bb_node(struct func_node *func, struct bb_node *bb)
+static void
+draw_bb_node(struct func_node *func, struct bb_node *bb, struct dump_data *dd)
 {
 	const char *shape;
 
@@ -398,13 +399,9 @@  static void draw_bb_node(struct func_node *func, struct bb_node *bb)
 		printf("EXIT");
 	} else {
 		unsigned int start_idx;
-		struct dump_data dd = {};
-
-		printf("{");
-		kernel_syms_load(&dd);
+		printf("{\\\n");
 		start_idx = bb->head - func->start;
-		dump_xlated_for_graph(&dd, bb->head, bb->tail, start_idx);
-		kernel_syms_destroy(&dd);
+		dump_xlated_for_graph(dd, bb->head, bb->tail, start_idx);
 		printf("}");
 	}
 
@@ -430,12 +427,12 @@  static void draw_bb_succ_edges(struct func_node *func, struct bb_node *bb)
 	}
 }
 
-static void func_output_bb_def(struct func_node *func)
+static void func_output_bb_def(struct func_node *func, struct dump_data *dd)
 {
 	struct bb_node *bb;
 
 	list_for_each_entry(bb, &func->bbs, l) {
-		draw_bb_node(func, bb);
+		draw_bb_node(func, bb, dd);
 	}
 }
 
@@ -455,7 +452,7 @@  static void func_output_edges(struct func_node *func)
 	       func_idx, ENTRY_BLOCK_INDEX, func_idx, EXIT_BLOCK_INDEX);
 }
 
-static void cfg_dump(struct cfg *cfg)
+static void cfg_dump(struct cfg *cfg, struct dump_data *dd)
 {
 	struct func_node *func;
 
@@ -463,14 +460,14 @@  static void cfg_dump(struct cfg *cfg)
 	list_for_each_entry(func, &cfg->funcs, l) {
 		printf("subgraph \"cluster_%d\" {\n\tstyle=\"dashed\";\n\tcolor=\"black\";\n\tlabel=\"func_%d ()\";\n",
 		       func->idx, func->idx);
-		func_output_bb_def(func);
+		func_output_bb_def(func, dd);
 		func_output_edges(func);
 		printf("}\n");
 	}
 	printf("}\n");
 }
 
-void dump_xlated_cfg(void *buf, unsigned int len)
+void dump_xlated_cfg(struct dump_data *dd, void *buf, unsigned int len)
 {
 	struct bpf_insn *insn = buf;
 	struct cfg cfg;
@@ -479,7 +476,7 @@  void dump_xlated_cfg(void *buf, unsigned int len)
 	if (cfg_build(&cfg, insn, len))
 		return;
 
-	cfg_dump(&cfg);
+	cfg_dump(&cfg, dd);
 
 	cfg_destroy(&cfg);
 }
diff --git a/tools/bpf/bpftool/cfg.h b/tools/bpf/bpftool/cfg.h
index e144257ea6d2..909d17e6d4c2 100644
--- a/tools/bpf/bpftool/cfg.h
+++ b/tools/bpf/bpftool/cfg.h
@@ -4,6 +4,8 @@ 
 #ifndef __BPF_TOOL_CFG_H
 #define __BPF_TOOL_CFG_H
 
-void dump_xlated_cfg(void *buf, unsigned int len);
+#include "xlated_dumper.h"
+
+void dump_xlated_cfg(struct dump_data *dd, void *buf, unsigned int len);
 
 #endif /* __BPF_TOOL_CFG_H */
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 0ef373cef4c7..e9ee514b22d4 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -229,6 +229,8 @@  void btf_dump_linfo_plain(const struct btf *btf,
 			  const char *prefix, bool linum);
 void btf_dump_linfo_json(const struct btf *btf,
 			 const struct bpf_line_info *linfo, bool linum);
+void btf_dump_linfo_dotlabel(const struct btf *btf,
+			     const struct bpf_line_info *linfo);
 
 struct nlattr;
 struct ifinfomsg;
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index afbe3ec342c8..d855118f0d96 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -840,11 +840,6 @@  prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 					      false))
 				goto exit_free;
 		}
-	} else if (visual) {
-		if (json_output)
-			jsonw_null(json_wtr);
-		else
-			dump_xlated_cfg(buf, member_len);
 	} else {
 		kernel_syms_load(&dd);
 		dd.nr_jited_ksyms = info->nr_jited_ksyms;
@@ -854,12 +849,14 @@  prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 		dd.finfo_rec_size = info->func_info_rec_size;
 		dd.prog_linfo = prog_linfo;
 
-		if (json_output)
-			dump_xlated_json(&dd, buf, member_len, opcodes,
-					 linum);
+		if (json_output && visual)
+			jsonw_null(json_wtr);
+		else if (json_output)
+			dump_xlated_json(&dd, buf, member_len, opcodes, linum);
+		else if (visual)
+			dump_xlated_cfg(&dd, buf, member_len);
 		else
-			dump_xlated_plain(&dd, buf, member_len, opcodes,
-					  linum);
+			dump_xlated_plain(&dd, buf, member_len, opcodes, linum);
 		kernel_syms_destroy(&dd);
 	}
 
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 3daa05d9bbb7..5fbe94aa8589 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -369,20 +369,50 @@  void dump_xlated_for_graph(struct dump_data *dd, void *buf_start, void *buf_end,
 		.cb_imm		= print_imm,
 		.private_data	= dd,
 	};
+	const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
+	const struct bpf_line_info *last_linfo = NULL;
+	struct bpf_func_info *record = dd->func_info;
 	struct bpf_insn *insn_start = buf_start;
 	struct bpf_insn *insn_end = buf_end;
 	struct bpf_insn *cur = insn_start;
+	struct btf *btf = dd->btf;
 	bool double_insn = false;
+	char func_sig[1024];
 
 	for (; cur <= insn_end; cur++) {
+		unsigned int insn_off;
+
 		if (double_insn) {
 			double_insn = false;
 			continue;
 		}
 		double_insn = cur->code == (BPF_LD | BPF_IMM | BPF_DW);
 
-		printf("% 4d: ", (int)(cur - insn_start + start_idx));
+		insn_off = (unsigned int)(cur - insn_start + start_idx);
+		if (btf && record) {
+			if (record->insn_off == insn_off) {
+				btf_dumper_type_only(btf, record->type_id,
+						     func_sig,
+						     sizeof(func_sig));
+				if (func_sig[0] != '\0')
+					printf("; %s:\\l\\\n", func_sig);
+				record = (void *)record + dd->finfo_rec_size;
+			}
+		}
+
+		if (prog_linfo) {
+			const struct bpf_line_info *linfo;
+
+			linfo = bpf_prog_linfo__lfind(prog_linfo, insn_off, 0);
+			if (linfo && linfo != last_linfo) {
+				btf_dump_linfo_dotlabel(btf, linfo);
+				last_linfo = linfo;
+			}
+		}
+
+		printf("%d: ", insn_off);
 		print_bpf_insn(&cbs, cur, true);
+
 		if (cur != insn_end)
 			printf(" | ");
 	}