[PATCH 28/31] perf llvm: Display eBPF compiling command in debug output

From: Arnaldo Carvalho de Melo
Date: Tue Mar 13 2018 - 08:08:09 EST


From: Jiri Olsa <jolsa@xxxxxxxxxx>

In addition to template, display also the real compile command line with
all the variables substituted.

llvm compiling command template: $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS ...
llvm compiling command : /usr/bin/clang -D__KERNEL__ -D__NR_CPUS__=24 -DLINUX_VERSION_CODE=0x41000 ...

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180312094313.18738-3-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/llvm-utils.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/tools/perf/util/llvm-utils.c b/tools/perf/util/llvm-utils.c
index 4952b429caa7..1cca0a2fa641 100644
--- a/tools/perf/util/llvm-utils.c
+++ b/tools/perf/util/llvm-utils.c
@@ -433,6 +433,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
char serr[STRERR_BUFSIZE];
char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
const char *template = llvm_param.clang_bpf_cmd_template;
+ char *command_echo, *command_out;

if (path[0] != '-' && realpath(path, abspath) == NULL) {
err = errno;
@@ -487,6 +488,16 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
(path[0] == '-') ? path : abspath);

pr_debug("llvm compiling command template: %s\n", template);
+
+ if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
+ goto errout;
+
+ err = read_from_pipe(command_echo, (void **) &command_out, NULL);
+ if (err)
+ goto errout;
+
+ pr_debug("llvm compiling command : %s\n", command_out);
+
err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
if (err) {
pr_err("ERROR:\tunable to compile %s\n", path);
@@ -497,6 +508,8 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
goto errout;
}

+ free(command_echo);
+ free(command_out);
free(kbuild_dir);
free(kbuild_include_opts);

@@ -509,6 +522,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
*p_obj_buf_sz = obj_buf_sz;
return 0;
errout:
+ free(command_echo);
free(kbuild_dir);
free(kbuild_include_opts);
free(obj_buf);
--
2.14.3