From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753984Ab1HZPig (ORCPT ); Fri, 26 Aug 2011 11:38:36 -0400 Received: from merlin.infradead.org ([205.233.59.134]:38950 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753849Ab1HZPhZ (ORCPT ); Fri, 26 Aug 2011 11:37:25 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Anton Blanchard , Eric B Munson , Ingo Molnar , Paul Mackerras , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH 5/6] perf symbols: Add some heuristics for choosing the best duplicate symbol Date: Fri, 26 Aug 2011 12:37:10 -0300 Message-Id: <1314373031-6687-6-git-send-email-acme@infradead.org> X-Mailer: git-send-email 1.6.2.5 In-Reply-To: <1314373031-6687-1-git-send-email-acme@infradead.org> References: <1314373031-6687-1-git-send-email-acme@infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by canuck.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anton Blanchard Try and pick the best symbol based on a few heuristics: - Prefer a non weak symbol over a weak one - Prefer a global symbol over a non global one - Prefer a symbol with less underscores (idea taken from kallsyms.c) - If all else fails, choose the symbol with the longest name Cc: Eric B Munson Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20110824065243.161953371@samba.org Signed-off-by: Anton Blanchard Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 88 insertions(+), 0 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 0d94ddb..870b3b8 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -86,6 +86,92 @@ bool symbol_type__is_a(char symbol_type, enum map_type map_type) } } +static int prefix_underscores_count(const char *str) +{ + const char *tail = str; + + while (*tail == '_') + tail++; + + return tail - str; +} + +#define SYMBOL_A 0 +#define SYMBOL_B 1 + +static int choose_best_symbol(struct symbol *syma, struct symbol *symb) +{ + s64 a; + s64 b; + + /* Prefer a symbol with non zero length */ + a = syma->end - syma->start; + b = symb->end - symb->start; + if ((b == 0) && (a > 0)) + return SYMBOL_A; + else if ((a == 0) && (b > 0)) + return SYMBOL_B; + + /* Prefer a non weak symbol over a weak one */ + a = syma->binding == STB_WEAK; + b = symb->binding == STB_WEAK; + if (b && !a) + return SYMBOL_A; + if (a && !b) + return SYMBOL_B; + + /* Prefer a global symbol over a non global one */ + a = syma->binding == STB_GLOBAL; + b = symb->binding == STB_GLOBAL; + if (a && !b) + return SYMBOL_A; + if (b && !a) + return SYMBOL_B; + + /* Prefer a symbol with less underscores */ + a = prefix_underscores_count(syma->name); + b = prefix_underscores_count(symb->name); + if (b > a) + return SYMBOL_A; + else if (a > b) + return SYMBOL_B; + + /* If all else fails, choose the symbol with the longest name */ + if (strlen(syma->name) >= strlen(symb->name)) + return SYMBOL_A; + else + return SYMBOL_B; +} + +static void symbols__fixup_duplicate(struct rb_root *symbols) +{ + struct rb_node *nd; + struct symbol *curr, *next; + + nd = rb_first(symbols); + + while (nd) { + curr = rb_entry(nd, struct symbol, rb_node); +again: + nd = rb_next(&curr->rb_node); + next = rb_entry(nd, struct symbol, rb_node); + + if (!nd) + break; + + if (curr->start != next->start) + continue; + + if (choose_best_symbol(curr, next) == SYMBOL_A) { + rb_erase(&next->rb_node, symbols); + goto again; + } else { + nd = rb_next(&curr->rb_node); + rb_erase(&curr->rb_node, symbols); + } + } +} + static void symbols__fixup_end(struct rb_root *symbols) { struct rb_node *nd, *prevnd = rb_first(symbols); @@ -692,6 +778,7 @@ int dso__load_kallsyms(struct dso *dso, const char *filename, if (dso__load_all_kallsyms(dso, filename, map) < 0) return -1; + symbols__fixup_duplicate(&dso->symbols[map->type]); symbols__fixup_end(&dso->symbols[map->type]); if (dso->kernel == DSO_TYPE_GUEST_KERNEL) @@ -1269,6 +1356,7 @@ new_symbol: * For misannotated, zeroed, ASM function sizes. */ if (nr > 0) { + symbols__fixup_duplicate(&dso->symbols[map->type]); symbols__fixup_end(&dso->symbols[map->type]); if (kmap) { /* -- 1.6.2.5