Commit 6243b9dc authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Move dwarf specific functions to dwarf-aux.c 



Move generic dwarf related functions from util/probe-finder.c to
util/dwarf-aux.c. Functions name and their prototype are also changed
accordingly. No functionality changes.

Suggested-and-Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1472546377-25612-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e47392bf

tools/perf/util/dwarf-aux.c

+179 −0
Original line number Diff line number Diff line
@@ -1085,3 +1085,182 @@ int die_get_var_range(Dwarf_Die *sp_die __maybe_unused, 
	return -ENOTSUP;

}

#endif



/*

 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list

 * @vr_die: a variable DIE

 */

static bool die_has_loclist(Dwarf_Die *vr_die)

{

	Dwarf_Attribute loc;

	int tag = dwarf_tag(vr_die);



	if (tag != DW_TAG_formal_parameter &&

	    tag != DW_TAG_variable)

		return false;



	return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&

		dwarf_whatform(&loc) == DW_FORM_sec_offset);

}



/*

 * die_is_optimized_target - Check if target program is compiled with

 * optimization

 * @cu_die: a CU DIE

 *

 * For any object in given CU whose DW_AT_location is a location list,

 * target program is compiled with optimization. This is applicable to

 * clang as well.

 */

bool die_is_optimized_target(Dwarf_Die *cu_die)

{

	Dwarf_Die tmp_die;



	if (die_has_loclist(cu_die))

		return true;



	if (!dwarf_child(cu_die, &tmp_die) &&

	    die_is_optimized_target(&tmp_die))

		return true;



	if (!dwarf_siblingof(cu_die, &tmp_die) &&

	    die_is_optimized_target(&tmp_die))

		return true;



	return false;

}



/*

 * die_search_idx - Search index of given line address

 * @lines: Line records of single CU

 * @nr_lines: Number of @lines

 * @addr: address we are looking for

 * @idx: index to be set by this function (return value)

 *

 * Search for @addr by looping over every lines of CU. If address

 * matches, set index of that line in @idx. Note that single source

 * line can have multiple line records. i.e. single source line can

 * have multiple index.

 */

static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,

			   Dwarf_Addr addr, unsigned long *idx)

{

	unsigned long i;

	Dwarf_Addr tmp;



	for (i = 0; i < nr_lines; i++) {

		if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))

			return false;



		if (tmp == addr) {

			*idx = i;

			return true;

		}

	}

	return false;

}



/*

 * die_get_postprologue_addr - Search next address after function prologue

 * @entrypc_idx: entrypc index

 * @lines: Line records of single CU

 * @nr_lines: Number of @lines

 * @hignpc: high PC address of function

 * @postprologue_addr: Next address after function prologue (return value)

 *

 * Look for prologue-end marker. If there is no explicit marker, return

 * address of next line record or next source line.

 */

static bool die_get_postprologue_addr(unsigned long entrypc_idx,

				      Dwarf_Lines *lines,

				      unsigned long nr_lines,

				      Dwarf_Addr highpc,

				      Dwarf_Addr *postprologue_addr)

{

	unsigned long i;

	int entrypc_lno, lno;

	Dwarf_Line *line;

	Dwarf_Addr addr;

	bool p_end;



	/* entrypc_lno is actual source line number */

	line = dwarf_onesrcline(lines, entrypc_idx);

	if (dwarf_lineno(line, &entrypc_lno))

		return false;



	for (i = entrypc_idx; i < nr_lines; i++) {

		line = dwarf_onesrcline(lines, i);



		if (dwarf_lineaddr(line, &addr) ||

		    dwarf_lineno(line, &lno)    ||

		    dwarf_lineprologueend(line, &p_end))

			return false;



		/* highpc is exclusive. [entrypc,highpc) */

		if (addr >= highpc)

			break;



		/* clang supports prologue-end marker */

		if (p_end)

			break;



		/* Actual next line in source */

		if (lno != entrypc_lno)

			break;



		/*

		 * Single source line can have multiple line records.

		 * For Example,

		 *     void foo() { printf("hello\n"); }

		 * contains two line records. One points to declaration and

		 * other points to printf() line. Variable 'lno' won't get

		 * incremented in this case but 'i' will.

		 */

		if (i != entrypc_idx)

			break;

	}



	dwarf_lineaddr(line, postprologue_addr);

	if (*postprologue_addr >= highpc)

		dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),

			       postprologue_addr);



	return true;

}



/*

 * die_skip_prologue - Use next address after prologue as probe location

 * @sp_die: a subprogram DIE

 * @cu_die: a CU DIE

 * @entrypc: entrypc of the function

 *

 * Function prologue prepares stack and registers before executing function

 * logic. When target program is compiled without optimization, function

 * parameter information is only valid after prologue. When we probe entrypc

 * of the function, and try to record function parameter, it contains

 * garbage value.

 */

void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,

		       Dwarf_Addr *entrypc)

{

	size_t nr_lines = 0;

	unsigned long entrypc_idx = 0;

	Dwarf_Lines *lines = NULL;

	Dwarf_Addr postprologue_addr;

	Dwarf_Addr highpc;



	if (dwarf_highpc(sp_die, &highpc))

		return;



	if (dwarf_getsrclines(cu_die, &lines, &nr_lines))

		return;



	if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))

		return;



	if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,

				       highpc, &postprologue_addr))

		return;



	*entrypc = postprologue_addr;

}

tools/perf/util/dwarf-aux.h

+8 −0
Original line number Diff line number Diff line
@@ -125,4 +125,12 @@ int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf); 
/* Get the name and type of given variable DIE, stored as "type\tname" */

int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf);

int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf);



/* Check if target program is compiled with optimization */

bool die_is_optimized_target(Dwarf_Die *cu_die);



/* Use next address after prologue as probe location */

void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,

		       Dwarf_Addr *entrypc);



#endif

tools/perf/util/probe-finder.c

+2 −134
Original line number Diff line number Diff line
@@ -907,138 +907,6 @@ static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf) 
	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);

}



static bool var_has_loclist(Dwarf_Die *cu_die)

{

	Dwarf_Attribute loc;

	int tag = dwarf_tag(cu_die);



	if (tag != DW_TAG_formal_parameter &&

	    tag != DW_TAG_variable)

		return false;



	return (dwarf_attr_integrate(cu_die, DW_AT_location, &loc) &&

		dwarf_whatform(&loc) == DW_FORM_sec_offset);

}



/*

 * For any object in given CU whose DW_AT_location is a location list,

 * target program is compiled with optimization.

 */

static bool optimized_target(Dwarf_Die *cu_die)

{

	Dwarf_Die tmp_die;



	if (var_has_loclist(cu_die))

		return true;



	if (!dwarf_child(cu_die, &tmp_die) && optimized_target(&tmp_die))

		return true;



	if (!dwarf_siblingof(cu_die, &tmp_die) && optimized_target(&tmp_die))

		return true;



	return false;

}



static bool get_entrypc_idx(Dwarf_Lines *lines, unsigned long nr_lines,

			    Dwarf_Addr pf_addr, unsigned long *entrypc_idx)

{

	unsigned long i;

	Dwarf_Addr addr;



	for (i = 0; i < nr_lines; i++) {

		if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &addr))

			return false;



		if (addr == pf_addr) {

			*entrypc_idx = i;

			return true;

		}

	}

	return false;

}



static bool get_postprologue_addr(unsigned long entrypc_idx,

				  Dwarf_Lines *lines,

				  unsigned long nr_lines,

				  Dwarf_Addr highpc,

				  Dwarf_Addr *postprologue_addr)

{

	unsigned long i;

	int entrypc_lno, lno;

	Dwarf_Line *line;

	Dwarf_Addr addr;

	bool p_end;



	/* entrypc_lno is actual source line number */

	line = dwarf_onesrcline(lines, entrypc_idx);

	if (dwarf_lineno(line, &entrypc_lno))

		return false;



	for (i = entrypc_idx; i < nr_lines; i++) {

		line = dwarf_onesrcline(lines, i);



		if (dwarf_lineaddr(line, &addr) ||

		    dwarf_lineno(line, &lno)    ||

		    dwarf_lineprologueend(line, &p_end))

			return false;



		/* highpc is exclusive. [entrypc,highpc) */

		if (addr >= highpc)

			break;



		/* clang supports prologue-end marker */

		if (p_end)

			break;



		/* Actual next line in source */

		if (lno != entrypc_lno)

			break;



		/*

		 * Single source line can have multiple line records.

		 * For Example,

		 *     void foo() { printf("hello\n"); }

		 * contains two line records. One points to declaration and

		 * other points to printf() line. Variable 'lno' won't get

		 * incremented in this case but 'i' will.

		 */

		if (i != entrypc_idx)

			break;

	}



	dwarf_lineaddr(line, postprologue_addr);

	if (*postprologue_addr >= highpc)

		dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),

			       postprologue_addr);



	return true;

}



static void __skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)

{

	size_t nr_lines = 0;

	unsigned long entrypc_idx = 0;

	Dwarf_Lines *lines = NULL;

	Dwarf_Addr postprologue_addr;

	Dwarf_Addr highpc;



	if (dwarf_highpc(sp_die, &highpc))

		return;



	if (dwarf_getsrclines(&pf->cu_die, &lines, &nr_lines))

		return;



	if (!get_entrypc_idx(lines, nr_lines, pf->addr, &entrypc_idx))

		return;



	if (!get_postprologue_addr(entrypc_idx, lines, nr_lines,

				   highpc, &postprologue_addr))

		return;



	pf->addr = postprologue_addr;

}



static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)

{

	struct perf_probe_point *pp = &pf->pev->point;
@@ -1048,7 +916,7 @@ static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf) 
		return;



	/* Compiled with optimization? */

	if (optimized_target(&pf->cu_die))

	if (die_is_optimized_target(&pf->cu_die))

		return;



	/* Don't know entrypc? */
@@ -1068,7 +936,7 @@ static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf) 
		"Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",

		pf->addr);



	__skip_prologue(sp_die, pf);

	die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);

}



static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)

CRA Git | Maintained and supported by SUSTech CRA and CCSE