tracing: Use TRACE_FLAGS macro to keep enums and strings matched
Use a cute little macro trick to keep the names of the trace flags file
guaranteed to match the corresponding masks.
The macro TRACE_FLAGS is defined as a serious of enum names followed by
the string name of the file that matches it. For example:
#define TRACE_FLAGS \
C(PRINT_PARENT, "print-parent"), \
C(SYM_OFFSET, "sym-offset"), \
C(SYM_ADDR, "sym-addr"), \
C(VERBOSE, "verbose"),
Now we can define the following:
#undef C
#define C(a, b) TRACE_ITER_##a##_BIT
enum trace_iterator_bits { TRACE_FLAGS };
The above creates:
enum trace_iterator_bits {
TRACE_ITER_PRINT_PARENT_BIT,
TRACE_ITER_SYM_OFFSET_BIT,
TRACE_ITER_SYM_ADDR_BIT,
TRACE_ITER_VERBOSE_BIT,
};
Then we can redefine C as:
#undef C
#define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT)
enum trace_iterator_flags { TRACE_FLAGS };
Which creates:
enum trace_iterator_flags {
TRACE_ITER_PRINT_PARENT = (1 << TRACE_ITER_PRINT_PARENT_BIT),
TRACE_ITER_SYM_OFFSET = (1 << TRACE_ITER_SYM_OFFSET_BIT),
TRACE_ITER_SYM_ADDR = (1 << TRACE_ITER_SYM_ADDR_BIT),
TRACE_ITER_VERBOSE = (1 << TRACE_ITER_VERBOSE_BIT),
};
Then finally we can create the list of file names:
#undef C
#define C(a, b) b
static const char *trace_options[] = {
TRACE_FLAGS
NULL
};
Which creates:
static const char *trace_options[] = {
"print-parent",
"sym-offset",
"sym-addr",
"verbose",
NULL
};
The importance of this is that the strings match the bit index.
trace_options[TRACE_ITER_SYM_ADDR_BIT] == "sym-addr"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2 files changed