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perf probe: Query basic types from debuginfo
Query the basic type information (byte-size and signed-flag) from debuginfo and pass that to kprobe-tracer. This is especially useful for tracing the members of data structure, because each member has different byte-size on the memory. Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20100412171715.3790.23730.stgit@localhost6.localdomain6> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
parent
93ccae7a22
commit
4984912eb2
3 changed files with 80 additions and 8 deletions
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@ -740,6 +740,13 @@ static int synthesize_kprobe_trace_arg(struct kprobe_trace_arg *arg,
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buf += ret;
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buf += ret;
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buflen -= ret;
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buflen -= ret;
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}
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}
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/* Print argument type */
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if (arg->type) {
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ret = e_snprintf(buf, buflen, ":%s", arg->type);
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if (ret <= 0)
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return ret;
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buf += ret;
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}
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return buf - tmp;
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return buf - tmp;
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}
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}
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@ -848,6 +855,8 @@ void clear_kprobe_trace_event(struct kprobe_trace_event *tev)
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free(tev->args[i].name);
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free(tev->args[i].name);
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if (tev->args[i].value)
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if (tev->args[i].value)
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free(tev->args[i].value);
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free(tev->args[i].value);
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if (tev->args[i].type)
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free(tev->args[i].type);
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ref = tev->args[i].ref;
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ref = tev->args[i].ref;
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while (ref) {
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while (ref) {
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next = ref->next;
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next = ref->next;
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@ -23,6 +23,7 @@ struct kprobe_trace_arg_ref {
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struct kprobe_trace_arg {
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struct kprobe_trace_arg {
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char *name; /* Argument name */
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char *name; /* Argument name */
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char *value; /* Base value */
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char *value; /* Base value */
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char *type; /* Type name */
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struct kprobe_trace_arg_ref *ref; /* Referencing offset */
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struct kprobe_trace_arg_ref *ref; /* Referencing offset */
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};
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};
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@ -84,6 +84,9 @@ const char *x86_64_regs_table[X86_64_MAX_REGS] = {
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#define arch_regs_table x86_32_regs_table
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#define arch_regs_table x86_32_regs_table
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#endif
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#endif
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/* Kprobe tracer basic type is up to u64 */
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#define MAX_BASIC_TYPE_BITS 64
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/* Return architecture dependent register string (for kprobe-tracer) */
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/* Return architecture dependent register string (for kprobe-tracer) */
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static const char *get_arch_regstr(unsigned int n)
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static const char *get_arch_regstr(unsigned int n)
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{
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{
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@ -230,6 +233,31 @@ static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
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return die_mem;
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return die_mem;
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}
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}
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static bool die_is_signed_type(Dwarf_Die *tp_die)
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{
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Dwarf_Attribute attr;
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Dwarf_Word ret;
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if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
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dwarf_formudata(&attr, &ret) != 0)
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return false;
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return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
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ret == DW_ATE_signed_fixed);
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}
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static int die_get_byte_size(Dwarf_Die *tp_die)
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{
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Dwarf_Attribute attr;
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Dwarf_Word ret;
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if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
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dwarf_formudata(&attr, &ret) != 0)
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return 0;
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return (int)ret;
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}
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/* Return values for die_find callbacks */
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/* Return values for die_find callbacks */
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enum {
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enum {
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DIE_FIND_CB_FOUND = 0, /* End of Search */
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DIE_FIND_CB_FOUND = 0, /* End of Search */
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@ -406,13 +434,42 @@ static void convert_location(Dwarf_Op *op, struct probe_finder *pf)
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}
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}
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}
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}
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static void convert_variable_type(Dwarf_Die *vr_die,
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struct kprobe_trace_arg *targ)
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{
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Dwarf_Die type;
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char buf[16];
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int ret;
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if (die_get_real_type(vr_die, &type) == NULL)
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die("Failed to get a type information of %s.",
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dwarf_diename(vr_die));
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ret = die_get_byte_size(&type) * 8;
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if (ret) {
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/* Check the bitwidth */
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if (ret > MAX_BASIC_TYPE_BITS) {
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pr_warning(" Warning: %s exceeds max-bitwidth."
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" Cut down to %d bits.\n",
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dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
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ret = MAX_BASIC_TYPE_BITS;
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}
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ret = snprintf(buf, 16, "%c%d",
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die_is_signed_type(&type) ? 's' : 'u', ret);
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if (ret < 0 || ret >= 16)
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die("Failed to convert variable type.");
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targ->type = xstrdup(buf);
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}
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}
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static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
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static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
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struct perf_probe_arg_field *field,
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struct perf_probe_arg_field *field,
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struct kprobe_trace_arg_ref **ref_ptr)
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struct kprobe_trace_arg_ref **ref_ptr,
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Dwarf_Die *die_mem)
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{
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{
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struct kprobe_trace_arg_ref *ref = *ref_ptr;
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struct kprobe_trace_arg_ref *ref = *ref_ptr;
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Dwarf_Attribute attr;
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Dwarf_Attribute attr;
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Dwarf_Die member;
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Dwarf_Die type;
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Dwarf_Die type;
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Dwarf_Word offs;
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Dwarf_Word offs;
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@ -450,26 +507,27 @@ static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
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die("Structure on a register is not supported yet.");
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die("Structure on a register is not supported yet.");
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}
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}
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if (die_find_member(&type, field->name, &member) == NULL)
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if (die_find_member(&type, field->name, die_mem) == NULL)
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die("%s(tyep:%s) has no member %s.", varname,
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die("%s(tyep:%s) has no member %s.", varname,
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dwarf_diename(&type), field->name);
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dwarf_diename(&type), field->name);
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/* Get the offset of the field */
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/* Get the offset of the field */
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if (dwarf_attr(&member, DW_AT_data_member_location, &attr) == NULL ||
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if (dwarf_attr(die_mem, DW_AT_data_member_location, &attr) == NULL ||
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dwarf_formudata(&attr, &offs) != 0)
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dwarf_formudata(&attr, &offs) != 0)
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die("Failed to get the offset of %s.", field->name);
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die("Failed to get the offset of %s.", field->name);
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ref->offset += (long)offs;
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ref->offset += (long)offs;
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/* Converting next field */
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/* Converting next field */
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if (field->next)
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if (field->next)
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convert_variable_fields(&member, field->name, field->next,
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convert_variable_fields(die_mem, field->name, field->next,
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&ref);
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&ref, die_mem);
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}
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}
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/* Show a variables in kprobe event format */
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/* Show a variables in kprobe event format */
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static void convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
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static void convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
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{
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{
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Dwarf_Attribute attr;
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Dwarf_Attribute attr;
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Dwarf_Die die_mem;
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Dwarf_Op *expr;
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Dwarf_Op *expr;
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size_t nexpr;
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size_t nexpr;
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int ret;
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int ret;
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@ -483,9 +541,13 @@ static void convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
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convert_location(expr, pf);
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convert_location(expr, pf);
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if (pf->pvar->field)
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if (pf->pvar->field) {
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convert_variable_fields(vr_die, pf->pvar->var,
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convert_variable_fields(vr_die, pf->pvar->var,
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pf->pvar->field, &pf->tvar->ref);
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pf->pvar->field, &pf->tvar->ref,
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&die_mem);
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vr_die = &die_mem;
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}
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convert_variable_type(vr_die, pf->tvar);
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/* *expr will be cached in libdw. Don't free it. */
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/* *expr will be cached in libdw. Don't free it. */
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return ;
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return ;
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error:
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error:
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