1 files changed, 118 insertions, 35 deletions

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 469c0264ed29..40eeaf07725b 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -74,16 +74,104 @@ static void dso__set_sorted_by_name(struct dso *dso, enum map_type type)
 
 bool symbol_type__is_a(char symbol_type, enum map_type map_type)
 {
+        symbol_type = toupper(symbol_type);
+
         switch (map_type) {
         case MAP__FUNCTION:
                 return symbol_type == 'T' || symbol_type == 'W';
         case MAP__VARIABLE:
-                return symbol_type == 'D' || symbol_type == 'd';
+                return symbol_type == 'D';
         default:
                 return false;
         }
 }
 
+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);
@@ -438,18 +526,11 @@ int kallsyms__parse(const char *filename, void *arg,
         char *line = NULL;
         size_t n;
         int err = -1;
-        u64 prev_start = 0;
-        char prev_symbol_type = 0;
-        char *prev_symbol_name;
         FILE *file = fopen(filename, "r");
 
         if (file == NULL)
                 goto out_failure;
 
-        prev_symbol_name = malloc(KSYM_NAME_LEN);
-        if (prev_symbol_name == NULL)
-                goto out_close;
-
         err = 0;
 
         while (!feof(file)) {
@@ -470,7 +551,7 @@ int kallsyms__parse(const char *filename, void *arg,
                 if (len + 2 >= line_len)
                         continue;
 
-                symbol_type = toupper(line[len]);
+                symbol_type = line[len];
                 len += 2;
                 symbol_name = line + len;
                 len = line_len - len;
@@ -480,24 +561,18 @@ int kallsyms__parse(const char *filename, void *arg,
                         break;
                 }
 
-                if (prev_symbol_type) {
-                        u64 end = start;
-                        if (end != prev_start)
-                                --end;
-                        err = process_symbol(arg, prev_symbol_name,
-                                             prev_symbol_type, prev_start, end);
-                        if (err)
-                                break;
-                }
-
-                memcpy(prev_symbol_name, symbol_name, len + 1);
-                prev_symbol_type = symbol_type;
-                prev_start = start;
+                /*
+                 * module symbols are not sorted so we add all
+                 * symbols with zero length and rely on
+                 * symbols__fixup_end() to fix it up.
+                 */
+                err = process_symbol(arg, symbol_name,
+                                     symbol_type, start, start);
+                if (err)
+                        break;
         }
 
-        free(prev_symbol_name);
         free(line);
-out_close:
         fclose(file);
         return err;
 
@@ -703,6 +778,9 @@ 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)
                 dso->symtab_type = SYMTAB__GUEST_KALLSYMS;
         else
@@ -1092,8 +1170,7 @@ static int dso__load_sym(struct dso *dso, struct map *map, const char *name,
         if (dso->has_build_id) {
                 u8 build_id[BUILD_ID_SIZE];
 
-                if (elf_read_build_id(elf, build_id,
-                                      BUILD_ID_SIZE) != BUILD_ID_SIZE)
+                if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
                         goto out_elf_end;
 
                 if (!dso__build_id_equal(dso, build_id))
@@ -1111,6 +1188,8 @@ static int dso__load_sym(struct dso *dso, struct map *map, const char *name,
         }
 
         opdsec = elf_section_by_name(elf, &ehdr, &opdshdr, ".opd", &opdidx);
+        if (opdshdr.sh_type != SHT_PROGBITS)
+                opdsec = NULL;
         if (opdsec)
                 opddata = elf_rawdata(opdsec, NULL);
 
@@ -1276,6 +1355,7 @@ 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) {
                         /*
@@ -1362,8 +1442,8 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size)
         ptr = data->d_buf;
         while (ptr < (data->d_buf + data->d_size)) {
                 GElf_Nhdr *nhdr = ptr;
-                int namesz = NOTE_ALIGN(nhdr->n_namesz),
-                    descsz = NOTE_ALIGN(nhdr->n_descsz);
+                size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
+                       descsz = NOTE_ALIGN(nhdr->n_descsz);
                 const char *name;
 
                 ptr += sizeof(*nhdr);
@@ -1372,8 +1452,10 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size)
                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
                     nhdr->n_namesz == sizeof("GNU")) {
                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
-                                memcpy(bf, ptr, BUILD_ID_SIZE);
-                                err = BUILD_ID_SIZE;
+                                size_t sz = min(size, descsz);
+                                memcpy(bf, ptr, sz);
+                                memset(bf + sz, 0, size - sz);
+                                err = descsz;
                                 break;
                         }
                 }
@@ -1425,7 +1507,7 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
         while (1) {
                 char bf[BUFSIZ];
                 GElf_Nhdr nhdr;
-                int namesz, descsz;
+                size_t namesz, descsz;
 
                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
                         break;
@@ -1434,15 +1516,16 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
                 descsz = NOTE_ALIGN(nhdr.n_descsz);
                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
                     nhdr.n_namesz == sizeof("GNU")) {
-                        if (read(fd, bf, namesz) != namesz)
+                        if (read(fd, bf, namesz) != (ssize_t)namesz)
                                 break;
                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
-                                if (read(fd, build_id,
-                                    BUILD_ID_SIZE) == BUILD_ID_SIZE) {
+                                size_t sz = min(descsz, size);
+                                if (read(fd, build_id, sz) == (ssize_t)sz) {
+                                        memset(build_id + sz, 0, size - sz);
                                         err = 0;
                                         break;
                                 }
-                        } else if (read(fd, bf, descsz) != descsz)
+                        } else if (read(fd, bf, descsz) != (ssize_t)descsz)
                                 break;
                 } else {
                         int n = namesz + descsz;