[06/10] sparc: Implement backtrace on top <unwind-link.h>

Message ID 994e0ad746c4324afa738d675cc4bead4ba95291.1613577607.git.fweimer@redhat.com
State New
Headers show
Series
  • Unwinder interface consolidation
Related show

Commit Message

Florian Weimer via Libc-alpha Feb. 17, 2021, 4:03 p.m.
---
 sysdeps/sparc/backtrace.c | 66 +++++++++------------------------------
 1 file changed, 15 insertions(+), 51 deletions(-)

-- 
2.29.2

Comments

Florian Weimer via Libc-alpha March 1, 2021, 1:54 p.m. | #1
On 2/17/21 11:03 AM, Florian Weimer via Libc-alpha wrote:

LGTM. And the sparc version.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>


> ---

>  sysdeps/sparc/backtrace.c | 66 +++++++++------------------------------

>  1 file changed, 15 insertions(+), 51 deletions(-)

> 

> diff --git a/sysdeps/sparc/backtrace.c b/sysdeps/sparc/backtrace.c

> index 62196f0538..1bad755b7f 100644

> --- a/sysdeps/sparc/backtrace.c

> +++ b/sysdeps/sparc/backtrace.c

> @@ -21,9 +21,8 @@

>  #include <stddef.h>

>  #include <sysdep.h>

>  #include <sys/trap.h>

> -#include <dlfcn.h>

> -#include <unwind.h>

>  #include <backtrace.h>

> +#include <unwind-link.h>

>  

>  struct layout

>  {

> @@ -36,45 +35,12 @@ struct layout

>  struct trace_arg

>  {

>    void **array;

> +  struct unwind_link *unwind_link;

>    _Unwind_Word cfa;

>    int cnt;

>    int size;

>  };

>  

> -#ifdef SHARED

> -static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);

> -static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);

> -static _Unwind_Word (*unwind_getcfa) (struct _Unwind_Context *);

> -static void *libgcc_handle;

> -

> -/* Dummy version in case libgcc_s does not contain the real code.  */

> -static _Unwind_Word

> -dummy_getcfa (struct _Unwind_Context *ctx __attribute__ ((unused)))

> -{

> -  return 0;

> -}

> -

> -static void

> -init (void)

> -{

> -  libgcc_handle = __libc_dlopen ("libgcc_s.so.1");

> -

> -  if (libgcc_handle == NULL)

> -    return;

> -

> -  unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");

> -  unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");

> -  if (unwind_getip == NULL)

> -    unwind_backtrace = NULL;

> -  unwind_getcfa = (__libc_dlsym (libgcc_handle, "_Unwind_GetCFA")

> -		  ?: dummy_getcfa);

> -}

> -#else

> -# define unwind_backtrace _Unwind_Backtrace

> -# define unwind_getip _Unwind_GetIP

> -# define unwind_getcfa _Unwind_GetCFA

> -#endif

> -

>  static _Unwind_Reason_Code

>  backtrace_helper (struct _Unwind_Context *ctx, void *a)

>  {

> @@ -85,11 +51,12 @@ backtrace_helper (struct _Unwind_Context *ctx, void *a)

>       Skip it.  */

>    if (arg->cnt != -1)

>      {

> -      ip = unwind_getip (ctx);

> +      ip = UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetIP) (ctx);

>        arg->array[arg->cnt] = (void *) ip;

>  

>        /* Check whether we make any progress.  */

> -      _Unwind_Word cfa = unwind_getcfa (ctx);

> +      _Unwind_Word cfa

> +	= UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetCFA) (ctx);

>  

>        if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt]

>  	 && cfa == arg->cfa)

> @@ -104,23 +71,19 @@ backtrace_helper (struct _Unwind_Context *ctx, void *a)

>  int

>  __backtrace (void **array, int size)

>  {

> -  struct trace_arg arg = { .array = array, .cfa = 0, .size = size, .cnt = -1 };

> -  bool use_unwinder;

>    int count;

> +  struct trace_arg arg =

> +    {

> +     .array = array,

> +     .unwind_link = __libc_unwind_link_get (),

> +     .size = size,

> +     .cnt = -1,

> +    };

>  

>    if (size <= 0)

>      return 0;

>  

> -  use_unwinder = true;

> -#ifdef SHARED

> -  __libc_once_define (static, once);

> -

> -  __libc_once (once, init);

> -  if (unwind_backtrace == NULL)

> -    use_unwinder = false;

> -#endif

> -

> -  if (use_unwinder == false)

> +  if (arg.unwind_link == NULL)

>      {

>        struct layout *current;

>        unsigned long fp, i7;

> @@ -145,7 +108,8 @@ __backtrace (void **array, int size)

>      }

>    else

>      {

> -      unwind_backtrace (backtrace_helper, &arg);

> +      UNWIND_LINK_PTR (arg.unwind_link, _Unwind_Backtrace)

> +	(backtrace_helper, &arg);

>  

>        /* _Unwind_Backtrace seems to put NULL address above

>  	 _start.  Fix it up here.  */

> 



-- 
Cheers,
Carlos.

Patch

diff --git a/sysdeps/sparc/backtrace.c b/sysdeps/sparc/backtrace.c
index 62196f0538..1bad755b7f 100644
--- a/sysdeps/sparc/backtrace.c
+++ b/sysdeps/sparc/backtrace.c
@@ -21,9 +21,8 @@ 
 #include <stddef.h>
 #include <sysdep.h>
 #include <sys/trap.h>
-#include <dlfcn.h>
-#include <unwind.h>
 #include <backtrace.h>
+#include <unwind-link.h>
 
 struct layout
 {
@@ -36,45 +35,12 @@  struct layout
 struct trace_arg
 {
   void **array;
+  struct unwind_link *unwind_link;
   _Unwind_Word cfa;
   int cnt;
   int size;
 };
 
-#ifdef SHARED
-static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
-static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
-static _Unwind_Word (*unwind_getcfa) (struct _Unwind_Context *);
-static void *libgcc_handle;
-
-/* Dummy version in case libgcc_s does not contain the real code.  */
-static _Unwind_Word
-dummy_getcfa (struct _Unwind_Context *ctx __attribute__ ((unused)))
-{
-  return 0;
-}
-
-static void
-init (void)
-{
-  libgcc_handle = __libc_dlopen ("libgcc_s.so.1");
-
-  if (libgcc_handle == NULL)
-    return;
-
-  unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
-  unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
-  if (unwind_getip == NULL)
-    unwind_backtrace = NULL;
-  unwind_getcfa = (__libc_dlsym (libgcc_handle, "_Unwind_GetCFA")
-		  ?: dummy_getcfa);
-}
-#else
-# define unwind_backtrace _Unwind_Backtrace
-# define unwind_getip _Unwind_GetIP
-# define unwind_getcfa _Unwind_GetCFA
-#endif
-
 static _Unwind_Reason_Code
 backtrace_helper (struct _Unwind_Context *ctx, void *a)
 {
@@ -85,11 +51,12 @@  backtrace_helper (struct _Unwind_Context *ctx, void *a)
      Skip it.  */
   if (arg->cnt != -1)
     {
-      ip = unwind_getip (ctx);
+      ip = UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetIP) (ctx);
       arg->array[arg->cnt] = (void *) ip;
 
       /* Check whether we make any progress.  */
-      _Unwind_Word cfa = unwind_getcfa (ctx);
+      _Unwind_Word cfa
+	= UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetCFA) (ctx);
 
       if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt]
 	 && cfa == arg->cfa)
@@ -104,23 +71,19 @@  backtrace_helper (struct _Unwind_Context *ctx, void *a)
 int
 __backtrace (void **array, int size)
 {
-  struct trace_arg arg = { .array = array, .cfa = 0, .size = size, .cnt = -1 };
-  bool use_unwinder;
   int count;
+  struct trace_arg arg =
+    {
+     .array = array,
+     .unwind_link = __libc_unwind_link_get (),
+     .size = size,
+     .cnt = -1,
+    };
 
   if (size <= 0)
     return 0;
 
-  use_unwinder = true;
-#ifdef SHARED
-  __libc_once_define (static, once);
-
-  __libc_once (once, init);
-  if (unwind_backtrace == NULL)
-    use_unwinder = false;
-#endif
-
-  if (use_unwinder == false)
+  if (arg.unwind_link == NULL)
     {
       struct layout *current;
       unsigned long fp, i7;
@@ -145,7 +108,8 @@  __backtrace (void **array, int size)
     }
   else
     {
-      unwind_backtrace (backtrace_helper, &arg);
+      UNWIND_LINK_PTR (arg.unwind_link, _Unwind_Backtrace)
+	(backtrace_helper, &arg);
 
       /* _Unwind_Backtrace seems to put NULL address above
 	 _start.  Fix it up here.  */