tools/perf/util/probe-finder.c

Source file repositories/reference/linux-study-clean/tools/perf/util/probe-finder.c

File Facts

System
Linux kernel
Corpus path
tools/perf/util/probe-finder.c
Extension
.c
Size
49605 bytes
Lines
1964
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct find_scope_param {
	const char *function;
	const char *file;
	int line;
	int diff;
	Dwarf_Die *die_mem;
	bool found;
};

static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
{
	struct find_scope_param *fsp = data;
	const char *file;
	int lno;

	/* Skip if declared file name does not match */
	if (fsp->file) {
		file = die_get_decl_file(fn_die);
		if (!file || strcmp(fsp->file, file) != 0)
			return 0;
	}
	/* If the function name is given, that's what user expects */
	if (fsp->function) {
		if (die_match_name(fn_die, fsp->function)) {
			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
			fsp->found = true;
			return 1;
		}
	} else {
		/* With the line number, find the nearest declared DIE */
		dwarf_decl_line(fn_die, &lno);
		if (lno < fsp->line && fsp->diff > fsp->line - lno) {
			/* Keep a candidate and continue */
			fsp->diff = fsp->line - lno;
			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
			fsp->found = true;
		}
	}
	return 0;
}

/* Return innermost DIE */
static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
{
	struct find_scope_param *fsp = data;

	memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
	fsp->found = true;
	return 1;
}

/* Find an appropriate scope fits to given conditions */
static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
{
	struct find_scope_param fsp = {
		.function = pf->pev->point.function,
		.file = pf->fname,
		.line = pf->lno,
		.diff = INT_MAX,
		.die_mem = die_mem,
		.found = false,
	};
	int ret;

	ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
				   &fsp);
	if (!ret && !fsp.found)
		cu_walk_functions_at(&pf->cu_die, pf->addr,
				     find_inner_scope_cb, &fsp);

	return fsp.found ? die_mem : NULL;
}

static int verify_representive_line(struct probe_finder *pf, const char *fname,
				int lineno, Dwarf_Addr addr)
{
	const char *__fname, *__func = NULL;
	Dwarf_Die die_mem;
	int __lineno;

	/* Verify line number and address by reverse search */
	if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
		return 0;

	pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
	if (strcmp(fname, __fname) || lineno == __lineno)
		return 0;

	pr_warning("This line is sharing the address with other lines.\n");

Annotation

Implementation Notes