[Tizen] Reduce arm_phdr_cb call overheadsubmit/tizen_5.5/20200207.005700accepted/tizen/5.5/unified/20200207.122745

- Too many calls to arm_phdr_cb even though it get the same data.
- It caches an ARM_CB_DATA for libcoreclr.so, then reuse.

3 files changed, 48 insertions, 1 deletions

diff --git a/src/pal/src/libunwind/include/tdep-arm/libunwind_i.h b/src/pal/src/libunwind/include/tdep-arm/libunwind_i.h
index 2602f41c4f..608107bfd3 100644
--- a/src/pal/src/libunwind/include/tdep-arm/libunwind_i.h
+++ b/src/pal/src/libunwind/include/tdep-arm/libunwind_i.h
@@ -254,6 +254,8 @@ dwarf_put (struct dwarf_cursor *c, dwarf_loc_t loc, unw_word_t val)
 #define tdep_init                       UNW_OBJ(init)
 #define arm_find_proc_info              UNW_OBJ(find_proc_info)
 #define arm_put_unwind_info             UNW_OBJ(put_unwind_info)
+#define arm_cb_cache_data_init          UNW_OBJ(cb_cache_data_init)
+
 /* Platforms that support UNW_INFO_FORMAT_TABLE need to define
    tdep_search_unwind_table.  */
 #define tdep_search_unwind_table        UNW_OBJ(search_unwind_table)
@@ -296,6 +298,7 @@ extern int arm_find_proc_info (unw_addr_space_t as, unw_word_t ip,
                                void *arg);
 extern void arm_put_unwind_info (unw_addr_space_t as,
                                   unw_proc_info_t *pi, void *arg);
+extern void arm_cb_cache_data_init (void);
 extern int tdep_search_unwind_table (unw_addr_space_t as, unw_word_t ip,
                                      unw_dyn_info_t *di, unw_proc_info_t *pi,
                                      int need_unwind_info, void *arg);
diff --git a/src/pal/src/libunwind/src/arm/Gex_tables.c b/src/pal/src/libunwind/src/arm/Gex_tables.c
index d6573a65e0..1e7b0044b9 100644
--- a/src/pal/src/libunwind/src/arm/Gex_tables.c
+++ b/src/pal/src/libunwind/src/arm/Gex_tables.c
@@ -463,6 +463,16 @@ tdep_search_unwind_table (unw_addr_space_t as, unw_word_t ip,
 /**
  * Callback to dl_iterate_phdr to find infos about the ARM exidx segment.
  */
+struct arm_cb_cache_data
+{
+  unw_word_t start_ip;
+  unw_word_t end_ip;
+  unw_word_t name_ptr;
+  unw_word_t table_data;
+  unw_word_t table_len;
+};
+static struct arm_cb_cache_data g_cache_data = {0, 0, 0, 0, 0};
+
 static int
 arm_phdr_cb (struct dl_phdr_info *info, size_t size, void *data)
 {
@@ -527,7 +537,20 @@ arm_find_proc_info (unw_addr_space_t as, unw_word_t ip,
       cb_data.di.format = -1;
 
       SIGPROCMASK (SIG_SETMASK, &unwi_full_mask, &saved_mask);
-      ret = dl_iterate_phdr (arm_phdr_cb, &cb_data);
+      if (ip >= g_cache_data.start_ip && ip < g_cache_data.end_ip)
+      {
+        cb_data.di.format = UNW_INFO_FORMAT_ARM_EXIDX;
+        cb_data.di.start_ip = g_cache_data.start_ip;
+        cb_data.di.end_ip = g_cache_data.end_ip;
+        cb_data.di.u.rti.name_ptr = g_cache_data.name_ptr;
+        cb_data.di.u.rti.table_data = g_cache_data.table_data;
+        cb_data.di.u.rti.table_len = g_cache_data.table_len;
+      }
+      else
+      {
+        ret = dl_iterate_phdr (arm_phdr_cb, &cb_data);
+      }
+
       SIGPROCMASK (SIG_SETMASK, &saved_mask, NULL);
 
       if (cb_data.di.format != -1)
@@ -545,5 +568,25 @@ arm_put_unwind_info (unw_addr_space_t as, unw_proc_info_t *proc_info, void *arg)
 {
   /* it's a no-op */
 }
+
+HIDDEN void
+arm_cb_cache_data_init(void)
+{
+   struct arm_cb_data cb_data;
+   memset (&cb_data, 0, sizeof (cb_data));
+   cb_data.ip = (unw_word_t)arm_cb_cache_data_init;
+   cb_data.pi = 0;
+   cb_data.di.format = -1;
+
+  int ret = dl_iterate_phdr (arm_phdr_cb, &cb_data);
+  if (ret > 0)
+  {
+    g_cache_data.start_ip = cb_data.di.start_ip;
+    g_cache_data.end_ip = cb_data.di.end_ip;
+    g_cache_data.name_ptr = cb_data.di.u.rti.name_ptr;
+    g_cache_data.table_data = cb_data.di.u.rti.table_data;
+    g_cache_data.table_len = cb_data.di.u.rti.table_len;
+  }
+}
 #endif /* !UNW_REMOTE_ONLY */
 
diff --git a/src/pal/src/libunwind/src/arm/Gglobal.c b/src/pal/src/libunwind/src/arm/Gglobal.c
index 7b93fbd89a..82428e31cd 100644
--- a/src/pal/src/libunwind/src/arm/Gglobal.c
+++ b/src/pal/src/libunwind/src/arm/Gglobal.c
@@ -55,6 +55,7 @@ tdep_init (void)
 
     dwarf_init ();
 
+    arm_cb_cache_data_init ();
 #ifndef UNW_REMOTE_ONLY
     arm_local_addr_space_init ();
 #endif