From f182e3e13ca71b64b40fab1aef31fa6a78271648 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 11 Aug 2011 20:03:05 +0900 Subject: [PATCH] perf probe: Avoid searching variables in intermediate scopes Fix variable searching logic to search one in inner than local scope or global(CU) scope. In the other words, skip searching in intermediate scopes. e.g., in the following code, int var1; void inline infunc(int i) { i++; <--- [A] } void func(void) { int var1, var2; infunc(var2); } At [A], "var1" should point the global variable "var1", however, if user mis-typed as "var2", variable search should be failed. However, current logic searches variable infunc() scope, global scope, and then func() scope. Thus, it can find "var2" variable in func() scope. This may not be what user expects. So, it would better not search outer scopes except outermost (compile unit) scope which contains only global variables, when it failed to find given variable in local scope. E.g. Without this: $ perf probe -V pre_schedule --externs > without.vars With this: $ perf probe -V pre_schedule --externs > with.vars Check the diff: $ diff without.vars with.vars 88d87 < int cpu 133d131 < long unsigned int* switch_count These vars are actually in the scope of schedule(), the caller of pre_schedule(). Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Pekka Enberg Cc: Peter Zijlstra Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20110811110305.19900.94374.stgit@fedora15 Signed-off-by: Masami Hiramatsu Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-finder.c | 44 ++++++++++------------------------ 1 file changed, 13 insertions(+), 31 deletions(-) diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 5c83b7d3d8ef..114542a5a99c 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -615,9 +615,9 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf) /* Find a variable in a scope DIE */ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf) { - Dwarf_Die vr_die, *scopes; + Dwarf_Die vr_die; char buf[32], *ptr; - int ret, nscopes; + int ret = 0; if (!is_c_varname(pf->pvar->var)) { /* Copy raw parameters */ @@ -652,29 +652,16 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf) if (pf->tvar->name == NULL) return -ENOMEM; - pr_debug("Searching '%s' variable in context.\n", - pf->pvar->var); + pr_debug("Searching '%s' variable in context.\n", pf->pvar->var); /* Search child die for local variables and parameters. */ - if (die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) - ret = convert_variable(&vr_die, pf); - else { - /* Search upper class */ - nscopes = dwarf_getscopes_die(sc_die, &scopes); - ret = -ENOENT; - while (nscopes-- > 1) { - pr_debug("Searching variables in %s\n", - dwarf_diename(&scopes[nscopes])); - /* We should check this scope, so give dummy address */ - if (die_find_variable_at(&scopes[nscopes], - pf->pvar->var, 0, - &vr_die)) { - ret = convert_variable(&vr_die, pf); - break; - } - } - if (scopes) - free(scopes); + if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) { + /* Search again in global variables */ + if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die)) + ret = -ENOENT; } + if (ret == 0) + ret = convert_variable(&vr_die, pf); + if (ret < 0) pr_warning("Failed to find '%s' in this function.\n", pf->pvar->var); @@ -1242,8 +1229,8 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf) struct available_var_finder *af = container_of(pf, struct available_var_finder, pf); struct variable_list *vl; - Dwarf_Die die_mem, *scopes = NULL; - int ret, nscopes; + Dwarf_Die die_mem; + int ret; /* Check number of tevs */ if (af->nvls == af->max_vls) { @@ -1273,12 +1260,7 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf) goto out; /* Don't need to search child DIE for externs. */ af->child = false; - nscopes = dwarf_getscopes_die(sc_die, &scopes); - while (nscopes-- > 1) - die_find_child(&scopes[nscopes], collect_variables_cb, - (void *)af, &die_mem); - if (scopes) - free(scopes); + die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem); out: if (strlist__empty(vl->vars)) { -- 2.34.1