Commit 932dcc2c authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf dwarf-aux: Add die_collect_vars() 



The die_collect_vars() is to find all variable information in the scope
including function parameters.  The struct die_var_type is to save the
type of the variable with the location (reg and offset) as well as where
it's defined in the code (addr).

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240319055115.4063940-3-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent b508965d

tools/perf/util/dwarf-aux.c

+90 −28
Original line number Diff line number Diff line
@@ -1136,6 +1136,40 @@ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf) 
	return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));

}



#if defined(HAVE_DWARF_GETLOCATIONS_SUPPORT) || defined(HAVE_DWARF_CFI_SUPPORT)

static int reg_from_dwarf_op(Dwarf_Op *op)

{

	switch (op->atom) {

	case DW_OP_reg0 ... DW_OP_reg31:

		return op->atom - DW_OP_reg0;

	case DW_OP_breg0 ... DW_OP_breg31:

		return op->atom - DW_OP_breg0;

	case DW_OP_regx:

	case DW_OP_bregx:

		return op->number;

	default:

		break;

	}

	return -1;

}



static int offset_from_dwarf_op(Dwarf_Op *op)

{

	switch (op->atom) {

	case DW_OP_reg0 ... DW_OP_reg31:

	case DW_OP_regx:

		return 0;

	case DW_OP_breg0 ... DW_OP_breg31:

		return op->number;

	case DW_OP_bregx:

		return op->number2;

	default:

		break;

	}

	return -1;

}

#endif /* HAVE_DWARF_GETLOCATIONS_SUPPORT || HAVE_DWARF_CFI_SUPPORT */



#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT

/**

 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
@@ -1476,41 +1510,69 @@ Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr addr, 
		*offset = data.offset;

	return result;

}

#endif /* HAVE_DWARF_GETLOCATIONS_SUPPORT */



#ifdef HAVE_DWARF_CFI_SUPPORT

static int reg_from_dwarf_op(Dwarf_Op *op)

static int __die_collect_vars_cb(Dwarf_Die *die_mem, void *arg)

{

	switch (op->atom) {

	case DW_OP_reg0 ... DW_OP_reg31:

		return op->atom - DW_OP_reg0;

	case DW_OP_breg0 ... DW_OP_breg31:

		return op->atom - DW_OP_breg0;

	case DW_OP_regx:

	case DW_OP_bregx:

		return op->number;

	default:

		break;

	}

	return -1;

	struct die_var_type **var_types = arg;

	Dwarf_Die type_die;

	int tag = dwarf_tag(die_mem);

	Dwarf_Attribute attr;

	Dwarf_Addr base, start, end;

	Dwarf_Op *ops;

	size_t nops;

	struct die_var_type *vt;



	if (tag != DW_TAG_variable && tag != DW_TAG_formal_parameter)

		return DIE_FIND_CB_SIBLING;



	if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL)

		return DIE_FIND_CB_SIBLING;



	/*

	 * Only collect the first location as it can reconstruct the

	 * remaining state by following the instructions.

	 * start = 0 means it covers the whole range.

	 */

	if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0)

		return DIE_FIND_CB_SIBLING;



	if (die_get_real_type(die_mem, &type_die) == NULL)

		return DIE_FIND_CB_SIBLING;



	vt = malloc(sizeof(*vt));

	if (vt == NULL)

		return DIE_FIND_CB_END;



	vt->die_off = dwarf_dieoffset(&type_die);

	vt->addr = start;

	vt->reg = reg_from_dwarf_op(ops);

	vt->offset = offset_from_dwarf_op(ops);

	vt->next = *var_types;

	*var_types = vt;



	return DIE_FIND_CB_SIBLING;

}



static int offset_from_dwarf_op(Dwarf_Op *op)

/**

 * die_collect_vars - Save all variables and parameters

 * @sc_die: a scope DIE

 * @var_types: a pointer to save the resulting list

 *

 * Save all variables and parameters in the @sc_die and save them to @var_types.

 * The @var_types is a singly-linked list containing type and location info.

 * Actual type can be retrieved using dwarf_offdie() with 'die_off' later.

 *

 * Callers should free @var_types.

 */

void die_collect_vars(Dwarf_Die *sc_die, struct die_var_type **var_types)

{

	switch (op->atom) {

	case DW_OP_reg0 ... DW_OP_reg31:

	case DW_OP_regx:

		return 0;

	case DW_OP_breg0 ... DW_OP_breg31:

		return op->number;

	case DW_OP_bregx:

		return op->number2;

	default:

		break;

	}

	return -1;

	Dwarf_Die die_mem;



	die_find_child(sc_die, __die_collect_vars_cb, (void *)var_types, &die_mem);

}

#endif /* HAVE_DWARF_GETLOCATIONS_SUPPORT */



#ifdef HAVE_DWARF_CFI_SUPPORT

/**

 * die_get_cfa - Get frame base information

 * @dwarf: a Dwarf info

tools/perf/util/dwarf-aux.h

+17 −0
Original line number Diff line number Diff line
@@ -135,6 +135,15 @@ void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die, 
/* Get the list of including scopes */

int die_get_scopes(Dwarf_Die *cu_die, Dwarf_Addr pc, Dwarf_Die **scopes);



/* Variable type information */

struct die_var_type {

	struct die_var_type *next;

	u64 die_off;

	u64 addr;

	int reg;

	int offset;

};



#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT



/* Get byte offset range of given variable DIE */
@@ -149,6 +158,9 @@ Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg, 
Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr addr,

				     Dwarf_Die *die_mem, int *offset);



/* Save all variables and parameters in this scope */

void die_collect_vars(Dwarf_Die *sc_die, struct die_var_type **var_types);



#else /*  HAVE_DWARF_GETLOCATIONS_SUPPORT */



static inline int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
@@ -176,6 +188,11 @@ static inline Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die __maybe_unu 
	return NULL;

}



static inline void die_collect_vars(Dwarf_Die *sc_die __maybe_unused,

				    struct die_var_type **var_types __maybe_unused)

{

}



#endif /* HAVE_DWARF_GETLOCATIONS_SUPPORT */



#ifdef HAVE_DWARF_CFI_SUPPORT