perf probe: Support tracing an entry of array (b2a3c12b) · Commits · 戴 / test

tools/perf/Documentation/perf-probe.txt

+1 −1

Original line number	Diff line number	Diff line
		@@ -94,7 +94,7 @@ Each probe argument follows below syntax.

		[NAME=]LOCALVAR\|$retval\|%REG\|@SYMBOL[:TYPE]

		'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
		'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), local array with fixed index (e.g. array[1], var->array[0], var->pointer[2]), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
		'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo. You can specify 'string' type only for the local variable or structure member which is an array of or a pointer to 'char' or 'unsigned char' type.

		LINE SYNTAX

tools/perf/util/probe-event.c

+39 −17

Original line number	Diff line number	Diff line
		@@ -557,7 +557,7 @@ static int parse_perf_probe_point(char arg, struct perf_probe_event pev)
		/* Parse perf-probe event argument */
		static int parse_perf_probe_arg(char str, struct perf_probe_arg arg)
		{
		char *tmp;
		char tmp, goodname;
		struct perf_probe_arg_field **fieldp;

		pr_debug("parsing arg: %s into ", str);
		@@ -580,7 +580,7 @@ static int parse_perf_probe_arg(char str, struct perf_probe_arg arg)
		pr_debug("type:%s ", arg->type);
		}

		tmp = strpbrk(str, "-.");
		tmp = strpbrk(str, "-.[");
		if (!is_c_varname(str) \|\| !tmp) {
		/* A variable, register, symbol or special value */
		arg->var = strdup(str);
		@@ -590,10 +590,11 @@ static int parse_perf_probe_arg(char str, struct perf_probe_arg arg)
		return 0;
		}

		/* Structure fields */
		/* Structure fields or array element */
		arg->var = strndup(str, tmp - str);
		if (arg->var == NULL)
		return -ENOMEM;
		goodname = arg->var;
		pr_debug("%s, ", arg->var);
		fieldp = &arg->field;

		@@ -601,6 +602,19 @@ static int parse_perf_probe_arg(char str, struct perf_probe_arg arg)
		*fieldp = zalloc(sizeof(struct perf_probe_arg_field));
		if (*fieldp == NULL)
		return -ENOMEM;
		if (tmp == '[') { / Array */
		str = tmp;
		(*fieldp)->index = strtol(str + 1, &tmp, 0);
		(*fieldp)->ref = true;
		if (*tmp != ']' \|\| tmp == str + 1) {
		semantic_error("Array index must be a"
		" number.\n");
		return -EINVAL;
		}
		tmp++;
		if (*tmp == '\0')
		tmp = NULL;
		} else { /* Structure */
		if (*tmp == '.') {
		str = tmp + 1;
		(*fieldp)->ref = false;
		@@ -608,15 +622,18 @@ static int parse_perf_probe_arg(char str, struct perf_probe_arg arg)
		str = tmp + 2;
		(*fieldp)->ref = true;
		} else {
		semantic_error("Argument parse error: %s\n", str);
		semantic_error("Argument parse error: %s\n",
		str);
		return -EINVAL;
		}

		tmp = strpbrk(str, "-.");
		tmp = strpbrk(str, "-.[");
		}
		if (tmp) {
		(*fieldp)->name = strndup(str, tmp - str);
		if ((*fieldp)->name == NULL)
		return -ENOMEM;
		if (*str != '[')
		goodname = (*fieldp)->name;
		pr_debug("%s(%d), ", (fieldp)->name, (fieldp)->ref);
		fieldp = &(*fieldp)->next;
		}
		@@ -624,11 +641,13 @@ static int parse_perf_probe_arg(char str, struct perf_probe_arg arg)
		(*fieldp)->name = strdup(str);
		if ((*fieldp)->name == NULL)
		return -ENOMEM;
		if (*str != '[')
		goodname = (*fieldp)->name;
		pr_debug("%s(%d)\n", (fieldp)->name, (fieldp)->ref);

		/* If no name is specified, set the last field name */
		/* If no name is specified, set the last field name (not array index)*/
		if (!arg->name) {
		arg->name = strdup((*fieldp)->name);
		arg->name = strdup(goodname);
		if (arg->name == NULL)
		return -ENOMEM;
		}
		@@ -776,8 +795,11 @@ int synthesize_perf_probe_arg(struct perf_probe_arg pa, char buf, size_t len)
		len -= ret;

		while (field) {
		ret = e_snprintf(tmp, len, "%s%s", field->ref ? "->" : ".",
		field->name);
		if (field->name[0] == '[')
		ret = e_snprintf(tmp, len, "%s", field->name);
		else
		ret = e_snprintf(tmp, len, "%s%s",
		field->ref ? "->" : ".", field->name);
		if (ret <= 0)
		goto error;
		tmp += ret;

tools/perf/util/probe-event.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -50,6 +50,7 @@ struct perf_probe_point {
		struct perf_probe_arg_field {
		struct perf_probe_arg_field next; / Next field */
		char name; / Name of the field */
		long index; /* Array index number */
		bool ref; /* Referencing flag */
		};

tools/perf/util/probe-finder.c

+42 −6

Original line number	Diff line number	Diff line
		@@ -485,6 +485,9 @@ static int convert_variable_type(Dwarf_Die *vr_die,
		return -ENOENT;
		}

		pr_debug("%s type is %s.\n",
		dwarf_diename(vr_die), dwarf_diename(&type));

		if (cast && strcmp(cast, "string") == 0) { /* String type */
		ret = dwarf_tag(&type);
		if (ret != DW_TAG_pointer_type &&
		@@ -553,16 +556,44 @@ static int convert_variable_fields(Dwarf_Die vr_die, const char varname,
		struct kprobe_trace_arg_ref ref = ref_ptr;
		Dwarf_Die type;
		Dwarf_Word offs;
		int ret;
		int ret, tag;

		pr_debug("converting %s in %s\n", field->name, varname);
		if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get the type of %s.\n", varname);
		return -ENOENT;
		}
		pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
		tag = dwarf_tag(&type);

		if (field->name[0] == '[' &&
		(tag == DW_TAG_array_type \|\| tag == DW_TAG_pointer_type)) {
		if (field->next)
		/* Save original type for next field */
		memcpy(die_mem, &type, sizeof(*die_mem));
		/* Get the type of this array */
		if (die_get_real_type(&type, &type) == NULL) {
		pr_warning("Failed to get the type of %s.\n", varname);
		return -ENOENT;
		}
		pr_debug2("Array real type: (%x)\n",
		(unsigned)dwarf_dieoffset(&type));
		if (tag == DW_TAG_pointer_type) {
		ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
		if (ref == NULL)
		return -ENOMEM;
		if (*ref_ptr)
		(*ref_ptr)->next = ref;
		else
		*ref_ptr = ref;
		}
		ref->offset += die_get_byte_size(&type) * field->index;
		if (!field->next)
		/* Save vr_die for converting types */
		memcpy(die_mem, vr_die, sizeof(*die_mem));
		goto next;
		} else if (tag == DW_TAG_pointer_type) {
		/* Check the pointer and dereference */
		if (dwarf_tag(&type) == DW_TAG_pointer_type) {
		if (!field->ref) {
		pr_err("Semantic error: %s must be referred by '->'\n",
		field->name);
		@@ -588,10 +619,15 @@ static int convert_variable_fields(Dwarf_Die vr_die, const char varname,
		*ref_ptr = ref;
		} else {
		/* Verify it is a data structure */
		if (dwarf_tag(&type) != DW_TAG_structure_type) {
		if (tag != DW_TAG_structure_type) {
		pr_warning("%s is not a data structure.\n", varname);
		return -EINVAL;
		}
		if (field->name[0] == '[') {
		pr_err("Semantic error: %s is not a pointor nor array.",
		varname);
		return -EINVAL;
		}
		if (field->ref) {
		pr_err("Semantic error: %s must be referred by '.'\n",
		field->name);
		@@ -618,6 +654,7 @@ static int convert_variable_fields(Dwarf_Die vr_die, const char varname,
		}
		ref->offset += (long)offs;

		next:
		/* Converting next field */
		if (field->next)
		return convert_variable_fields(die_mem, field->name,
		@@ -667,7 +704,6 @@ static int find_variable(Dwarf_Die sp_die, struct probe_finder pf)
		char buf[32], *ptr;
		int ret;

		/* TODO: Support arrays */
		if (pf->pvar->name)
		pf->tvar->name = strdup(pf->pvar->name);
		else {

Admin message