[CTRACER]: Add support for "pointer classes"
A pointer class is one that has as one of its members a pointer to the target class, example: target class: sock pointer classes: sk_buff, socket Because struct sk_buff and struct socket has members that are pointers to a struct sock. This way we can follow all the struct socket and struct sk_buff methods and pass to the struct sock collector as $skb->sk, for instance. With this we now go all the way from the socket layer to the sk_buff layer, passing thru the sock layer. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo
parent
515738edee
commit
232b8b2684
188
ctracer.c
188
ctracer.c
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@ -19,6 +19,11 @@
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#include "dwarves_emit.h"
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#include "dwarves.h"
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/*
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* target class name
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*/
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static char *class_name;
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/*
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* List of compilation units being looked for functions with
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* pointers to the specified struct.
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@ -85,8 +90,17 @@ static struct structure *structure__new(struct tag *class, struct cu *cu)
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return self;
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}
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/*
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* structs that can be casted to the target class, e.g. i.e. that has the target
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* class at its first member.
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*/
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static LIST_HEAD(aliases);
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/*
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* structs have pointers to the target class.
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*/
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static LIST_HEAD(pointers);
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static struct structure *structures__find(struct list_head *list, const char *name)
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{
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struct structure *pos;
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@ -154,6 +168,7 @@ static struct tag *function__filter(struct tag *tag, struct cu *cu, void *cookie
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function = tag__function(tag);
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if (function__inlined(function) ||
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function->abstract_origin != 0 ||
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!list_empty(&function->tool_node) ||
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!ftype__has_parm_of_type(&function->proto, cookie, cu))
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return NULL;
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@ -181,11 +196,11 @@ static int cu_find_methods_iterator(struct cu *cu, void *cookie)
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{
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struct tag *target = cu__find_struct_by_name(cu, cookie, 0);
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INIT_LIST_HEAD(&cu->tool_list);
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if (target == NULL)
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return 0;
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INIT_LIST_HEAD(&cu->tool_list);
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return cu__for_each_tag(cu, find_methods_iterator, target, function__filter);
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}
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@ -520,6 +535,68 @@ static int class__emit_ostra_converter(struct tag *tag_self,
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return 0;
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}
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/*
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* We want just the DW_TAG_structure_type tags that have a member that is a pointer
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* to the target class.
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*/
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static struct tag *pointer_filter(struct tag *tag, struct cu *cu, void *target_tag)
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{
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struct type *type, *target_type;
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struct class_member *pos;
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const char *class_name;
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if (tag->tag != DW_TAG_structure_type)
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return NULL;
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type = tag__type(tag);
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if (type->nr_members == 0)
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return NULL;
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class_name = class__name(tag__class(tag), cu);
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if (class_name == NULL || structures__find(&pointers, class_name))
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return NULL;
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target_type = tag__type(target_tag);
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type__for_each_member(type, pos) {
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struct tag *ctype = cu__find_tag_by_id(cu, pos->tag.type);
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if (ctype->tag == DW_TAG_pointer_type && ctype->type == target_type->namespace.tag.id)
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return tag;
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}
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return NULL;
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}
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/*
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* Add the struct to the list of pointers since it matches pointer_filter
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* criteria.
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*/
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static int find_pointers_iterator(struct tag *tag, struct cu *cu,
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void *cookie __unused)
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{
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structures__add(&pointers, tag, cu);
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return 0;
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}
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/*
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* Iterate thru all the tags in the compilation unit, looking for classes
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* that have as one member that is a pointer to the target type.
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*/
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static int cu_find_pointers_iterator(struct cu *cu, void *class_name)
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{
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struct tag *target = cu__find_struct_by_name(cu, class_name, 0);
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if (target == NULL)
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return 0;
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return cu__for_each_tag(cu, find_pointers_iterator, target, pointer_filter);
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}
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static void class__find_pointers(const char *class_name)
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{
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cus__for_each_cu(methods_cus, cu_find_pointers_iterator, (void *)class_name, NULL);
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}
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/*
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* We want just the DW_TAG_structure_type tags that have as its first member
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* a struct of type target.
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@ -596,26 +673,11 @@ static void class__find_aliases(const char *class_name)
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cus__for_each_cu(methods_cus, cu_find_aliases_iterator, (void *)class_name, NULL);
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}
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static int class__emit_classes(struct tag *tag_self, struct cu *cu)
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static void emit_list_of_types(struct list_head *list)
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{
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struct class *self = tag__class(tag_self);
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int err = -1;
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char mini_class_name[128];
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struct structure *pos;
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snprintf(mini_class_name, sizeof(mini_class_name), "ctracer__mini_%s",
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class__name(self, cu));
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mini_class = class__clone_base_types(tag_self, cu, mini_class_name);
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if (mini_class == NULL)
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goto out;
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cus__emit_type_definitions(methods_cus, cu, tag_self, fp_classes);
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type__emit(tag_self, cu, NULL, NULL, fp_classes);
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fputc('\n', fp_classes);
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list_for_each_entry(pos, &aliases, node) {
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list_for_each_entry(pos, list, node) {
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struct type *type = tag__type(pos->class);
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/*
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* Lets look at the other CUs, perhaps we have already
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@ -634,6 +696,32 @@ static int class__emit_classes(struct tag *tag_self, struct cu *cu)
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tag__type(pos->class)->definition_emitted = 1;
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fputc('\n', fp_classes);
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}
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}
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static int class__emit_classes(struct tag *tag_self, struct cu *cu)
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{
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struct class *self = tag__class(tag_self);
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int err = -1;
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char mini_class_name[128];
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struct structure *pos;
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snprintf(mini_class_name, sizeof(mini_class_name), "ctracer__mini_%s",
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class__name(self, cu));
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mini_class = class__clone_base_types(tag_self, cu, mini_class_name);
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if (mini_class == NULL)
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goto out;
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cus__emit_type_definitions(methods_cus, cu, tag_self, fp_classes);
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type__emit(tag_self, cu, NULL, NULL, fp_classes);
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fputs("\n/* class aliases */", fp_classes);
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emit_list_of_types(&aliases);
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fputs("\n/* class with pointers */", fp_classes);
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emit_list_of_types(&pointers);
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class__fprintf(mini_class, cu, NULL, fp_classes);
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fputs(";\n\n", fp_classes);
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@ -651,7 +739,8 @@ out:
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* probe for the function exit.
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*/
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static int function__emit_probes(struct function *self, const struct cu *cu,
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const struct tag *target, int probe_type)
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const struct tag *target, int probe_type,
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const char *member)
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{
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struct parameter *pos;
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const char *name = function__name(self, cu);
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@ -677,15 +766,20 @@ static int function__emit_probes(struct function *self, const struct cu *cu,
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if (type == NULL || type->id != target->id)
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continue;
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if (member != NULL)
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fprintf(fp_methods, "\tif ($%s)\n\t", pos->name);
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fprintf(fp_methods,
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"\tctracer__method_hook(%d, %#llx, $%s, %zd);\n",
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"\tctracer__method_hook(%d, %#llx, $%s%s%s, %zd);\n",
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probe_type,
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(unsigned long long)self->proto.tag.id, pos->name,
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member ? "->" : "", member ?: "",
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class__size(mini_class));
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break;
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}
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fputs("}\n\n", fp_methods);
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fflush(fp_methods);
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return 0;
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}
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@ -703,8 +797,45 @@ static int cu_emit_probes_iterator(struct cu *cu, void *cookie)
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if (methods__add(&probes_emitted, function__name(pos, cu)) != 0)
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continue;
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pos->priv = (void *)1; /* Mark as visited, for the table iterator */
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function__emit_probes(pos, cu, target, 0); /* entry */
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function__emit_probes(pos, cu, target, 1); /* exit */
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function__emit_probes(pos, cu, target, 0, NULL); /* entry */
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function__emit_probes(pos, cu, target, 1, NULL); /* exit */
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}
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return 0;
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}
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/*
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* Iterate thru the list of methods previously collected by
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* cu_find_methods_iterator, emitting the probes for function entry.
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*/
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static int cu_emit_pointer_probes_iterator(struct cu *cu, void *cookie)
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{
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struct tag *target, *pointer;
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struct function *pos_tag;
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struct class_member *pos_member;
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/* This CU doesn't have our classes */
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if (list_empty(&cu->tool_list))
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return 0;
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target = cu__find_struct_by_name(cu, class_name, 1);
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pointer = cu__find_struct_by_name(cu, cookie, 0);
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/* for now just for the first member that is a pointer */
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type__for_each_member(tag__type(pointer), pos_member) {
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struct tag *ctype = cu__find_tag_by_id(cu, pos_member->tag.type);
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if (ctype->tag == DW_TAG_pointer_type && ctype->type == target->id)
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break;
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}
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list_for_each_entry(pos_tag, &cu->tool_list, tool_node) {
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if (methods__add(&probes_emitted, function__name(pos_tag, cu)) != 0)
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continue;
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pos_tag->priv = (void *)1; /* Mark as visited, for the table iterator */
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function__emit_probes(pos_tag, cu, pointer, 0, pos_member->name); /* entry */
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function__emit_probes(pos_tag, cu, pointer, 1, pos_member->name); /* exit */
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}
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return 0;
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@ -760,7 +891,6 @@ static const struct argp_option ctracer__options[] = {
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};
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static const char *dirname, *glob;
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static char *class_name;
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static int recursive;
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static error_t ctracer__options_parser(int key, char *arg,
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@ -914,6 +1044,7 @@ failure:
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fputs("\n#include \"ctracer_classes.h\"\n\n", fp_collector);
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class__find_aliases(class_name);
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class__find_pointers(class_name);
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class__emit_classes(class, cu);
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fputc('\n', fp_collector);
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@ -936,6 +1067,15 @@ failure:
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cus__for_each_cu(methods_cus, cu_emit_functions_table, fp_functions, NULL);
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}
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list_for_each_entry(pos, &pointers, node) {
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const char *pointer_name = class__name(tag__class(pos->class), pos->cu);
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cus__for_each_cu(methods_cus, cu_find_methods_iterator,
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(void *)pointer_name, NULL);
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cus__for_each_cu(methods_cus, cu_emit_pointer_probes_iterator,
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(void *)pointer_name, NULL);
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cus__for_each_cu(methods_cus, cu_emit_functions_table, fp_functions, NULL);
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}
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fclose(fp_methods);
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fclose(fp_collector);
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fclose(fp_functions);
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