bionic, libthread_db x86 fixes

Change-Id: I3be997f5f1f6a894a3c200d4f325cf3bfd428c66
Author: James Rose <james.rose@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>

libc/bionic/pthread.c

@@ -68,7 +68,13 @@ int  __futex_wait_ex(volatile void *ftx, int pshared, int val, const struct time
 #define  __likely(cond)    __builtin_expect(!!(cond), 1)
 #define  __unlikely(cond)  __builtin_expect(!!(cond), 0)
 
-void _thread_created_hook(pid_t thread_id) __attribute__((noinline));
+#ifdef __i386__
+#define ATTRIBUTES __attribute__((noinline)) __attribute__((fastcall))
+#else
+#define ATTRIBUTES __attribute__((noinline))
+#endif
+
+void ATTRIBUTES _thread_created_hook(pid_t thread_id);
 
 #define PTHREAD_ATTR_FLAG_DETACHED      0x00000001
 #define PTHREAD_ATTR_FLAG_USER_STACK    0x00000002

libc/bionic/ptrace.c

@@ -57,7 +57,12 @@ long ptrace(int request, pid_t pid, void * addr, void * data)
 /*
  * Hook for gdb to get notified when a thread is created
  */
-void _thread_created_hook(pid_t thread_id) __attribute__((noinline));
-void _thread_created_hook(pid_t thread_id)
+#ifdef __i386__
+#define ATTRIBUTES __attribute__((noinline)) __attribute__((fastcall))
+#else
+#define ATTRIBUTES __attribute__((noinline))
+#endif
+
+void ATTRIBUTES _thread_created_hook(pid_t thread_id)
 {
 }

libthread_db/Android.mk

@@ -22,12 +22,7 @@ include $(CLEAR_VARS)
 LOCAL_WHOLE_STATIC_LIBRARIES := libthread_db
 LOCAL_MODULE:=libthread_db
 LOCAL_SHARED_LIBRARIES := libdl libc
-
-# NOTE: Using --no-undefined results in a missing symbol that is defined inside
-# gdbserver and is resolved at runtime. Since there is no library containing
-# this symbol that we can link against, set LOCAL_ALLOW_UNDEFINED_SYMBOLS so
-# that --no-undefined is removed from the linker flags.
-LOCAL_ALLOW_UNDEFINED_SYMBOLS := true
+LOCAL_ALLOW_UNDEFINED_SYMBOLS := false
 LOCAL_SYSTEM_SHARED_LIBRARIES :=
 
 include $(BUILD_SHARED_LIBRARY)

libthread_db/include/thread_db.h

@@ -149,6 +149,10 @@ extern td_err_e td_thr_event_enable(td_thrhandle_t const * handle,
 extern td_err_e td_ta_thr_iter(td_thragent_t const * agent, td_thr_iter_f * func, void * cookie,
                                td_thr_state_e state, int32_t prio, sigset_t * sigmask, uint32_t user_flags);
 
+extern td_err_e td_thr_event_enable(td_thrhandle_t const * handle, td_event_e event);
+
+extern td_err_e td_thr_get_info(td_thrhandle_t const * handle, td_thrinfo_t * info);
+
 extern char const ** td_symbol_list(void);
 
 extern td_err_e td_thr_tls_get_addr(const td_thrhandle_t * th,

libthread_db/libthread_db.c

@@ -81,6 +81,25 @@ _event_getmsg_helper(td_thrhandle_t const * handle, void * bkpt_addr)
 {
     void * pc;
 
+#ifdef __i386__
+    /* Get the eip from offset 12*4 = 48 as defined in the struct
+     * user_regs_struct in user_32.h
+     */
+    pc = (void *)ptrace(PTRACE_PEEKUSR, handle->tid, (void *)48 /* eip */, NULL);
+    /* FIXME - pc is a non-decremented breakpoint address, hence the
+     * addition of 1 on test.  This seems to work for the thread hook
+     * function in libc.so but should be properly fixed.
+     */
+    if (pc == ((int)bkpt_addr + 1)) {
+        /* The hook function takes the id of the new thread as it's first
+         * param, so grab it from ecx at offset 4 in struct user_regs_struct
+         * (using fastcall convention for x86)
+         */
+        gEventMsgHandle.pid = ptrace(PTRACE_PEEKUSR, handle->tid, (void *)4 /* ecx */, NULL);
+        gEventMsgHandle.tid = gEventMsgHandle.pid;
+        return 0x42;
+    }
+#else
     pc = (void *)ptrace(PTRACE_PEEKUSR, handle->tid, (void *)60 /* r15/pc */, NULL);
 
     if (pc == bkpt_addr) {
@@ -90,6 +109,7 @@ _event_getmsg_helper(td_thrhandle_t const * handle, void * bkpt_addr)
         gEventMsgHandle.tid = gEventMsgHandle.pid;
         return 0x42;
     }
+#endif
     return 0;
 }
 
@@ -156,7 +176,7 @@ td_ta_event_addr(td_thragent_t const * agent, td_event_e event, td_notify_t * no
 {
     int32_t err;
 
-    /* 
+    /*
      * This is nasty, ps_pglobal_lookup is implemented in gdbserver and looks up
      * the symbol from it's cache, which is populated at start time with the
      * symbols returned from td_symbol_list via calls back to the host.