[PATCH 3/4] [nto] Fix nto target stopped by watchpoint.

[Aleksandar Ristovski <aristovski@qnx.com>]

Fix stopped by watchpoint detection: add inferior data, use inferior data
for storing last stopped flags needed for detection.
Add binary sniffing for QNX osabi.

        * nto-procfs.c (procfs_wait): Set stopped_flags.
        (procfs_stopped_by_watchpoint): Use flags stored in inferior data.
        * nto-tdep.c (QNX_NOTE_NAME, QNX_INFO_SECT_NAME): New defines.
        (nto_inferior_data_reg): New definition.
        (nto_sniff_abi_note_section): New function.
        (nto_elf_osabi_sniffer): Use nto_sniff_abi_note_section.
        (nto_new_inferior_data, nto_inferior_data_cleanup, nto_inferior_data):
        New functions.
        (_initialize_nto_tdep): New forward declaration, new function.
        * nto-tdep.h (nto_inferior_data): New struct.
        (nto_inferior_data): New function declaration.
---
 gdb/ChangeLog    | 14 +++++++++
 gdb/nto-procfs.c | 21 ++++++++++++-
 gdb/nto-tdep.c   | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 gdb/nto-tdep.h   | 12 ++++++++
 4 files changed, 133 insertions(+), 4 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 04c9f0a..1aa8a68 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,17 @@
+<2015-3>  Aleksandar Ristovski  <aristovski@qnx.com>
+
+	* nto-procfs.c (procfs_wait): Set stopped_flags.
+	(procfs_stopped_by_watchpoint): Use flags stored in inferior data.
+	* nto-tdep.c (QNX_NOTE_NAME, QNX_INFO_SECT_NAME): New defines.
+	(nto_inferior_data_reg): New definition.
+	(nto_sniff_abi_note_section): New function.
+	(nto_elf_osabi_sniffer): Use nto_sniff_abi_note_section.
+	(nto_new_inferior_data, nto_inferior_data_cleanup, nto_inferior_data):
+	New functions.
+	(_initialize_nto_tdep): New forward declaration, new function.
+	* nto-tdep.h (nto_inferior_data): New struct.
+	(nto_inferior_data): New function declaration.
+
 <2015-2>  Aleksandar Ristovski  <aristovski@qnx.com>
 
 	* nto-procfs.c (sys/auxv.h): Include.
diff --git a/gdb/nto-procfs.c b/gdb/nto-procfs.c
index a4b5ce8..ae7329c 100644
--- a/gdb/nto-procfs.c
+++ b/gdb/nto-procfs.c
@@ -786,6 +786,9 @@ procfs_wait (struct target_ops *ops,
       devctl (ctl_fd, DCMD_PROC_STATUS, &status, sizeof (status), 0);
     }
 
+  nto_inferior_data (NULL)->stopped_flags = status.flags;
+  nto_inferior_data (NULL)->stopped_pc = status.ip;
+
   if (status.flags & _DEBUG_FLAG_SSTEP)
     {
       ourstatus->kind = TARGET_WAITKIND_STOPPED;
@@ -1630,5 +1633,21 @@ procfs_insert_hw_watchpoint (struct target_ops *self,
 static int
 procfs_stopped_by_watchpoint (struct target_ops *ops)
 {
-  return 0;
+  /* NOTE: nto_stopped_by_watchpoint will be called ONLY while we are 
+     stopped due to a SIGTRAP.  This assumes gdb works in 'all-stop' mode;
+     future gdb versions will likely run in 'non-stop' mode in which case 
+     we will have to store/examine statuses per thread in question.  
+     Until then, this will work fine.  */
+
+  struct inferior *inf = current_inferior ();
+  struct nto_inferior_data *inf_data;
+
+  gdb_assert (inf != NULL);
+
+  inf_data = nto_inferior_data (inf);
+
+  return inf_data->stopped_flags
+	 & (_DEBUG_FLAG_TRACE_RD
+	    | _DEBUG_FLAG_TRACE_WR
+	    | _DEBUG_FLAG_TRACE_MODIFY);
 }
diff --git a/gdb/nto-tdep.c b/gdb/nto-tdep.c
index 63094e8..62dbf8b 100644
--- a/gdb/nto-tdep.c
+++ b/gdb/nto-tdep.c
@@ -33,6 +33,9 @@
 #include "objfiles.h"
 #include "symfile.h"
 
+#define QNX_NOTE_NAME	"QNX"
+#define QNX_INFO_SECT_NAME "QNX_info"
+
 #ifdef __CYGWIN__
 #include <sys/cygwin.h>
 #endif
@@ -47,6 +50,8 @@ static char default_nto_target[] = "";
 
 struct nto_target_ops current_nto_target;
 
+static const struct inferior_data *nto_inferior_data_reg;
+
 static char *
 nto_target (void)
 {
@@ -331,12 +336,51 @@ nto_dummy_supply_regset (struct regcache *regcache, char *regs)
   /* Do nothing.  */
 }
 
+static void
+nto_sniff_abi_note_section (bfd *abfd, asection *sect, void *obj)
+{
+  const char *sectname;
+  unsigned int sectsize;
+  char *note; // buffer holding the section contents
+  unsigned int namelen;
+  const char *name;
+
+  sectname = bfd_get_section_name (abfd, sect);
+  sectsize = bfd_section_size (abfd, sect);
+
+  /* TODO: limit the note size here, for now limit is 128 bytes
+     (enough to check the name and type).  */
+  if (sectsize > 128)
+    sectsize = 128;
+
+  if (sectname && strstr (sectname, QNX_INFO_SECT_NAME) != NULL)
+    *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+
+  if (sectname && strstr (sectname, "note") != NULL)
+    {
+      note = alloca (sectsize);
+      bfd_get_section_contents (abfd, sect, note, 0, sectsize);
+      namelen = (unsigned int) bfd_h_get_32 (abfd, note);
+      name = note + 12;
+
+      if (namelen > 0
+	  && (0 == strcmp (name, QNX_NOTE_NAME)))
+        *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+    }
+}
+
 enum gdb_osabi
 nto_elf_osabi_sniffer (bfd *abfd)
 {
-  if (nto_is_nto_target)
+  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
+
+  bfd_map_over_sections (abfd,
+			 nto_sniff_abi_note_section,
+			 &osabi);
+
+  if (osabi == GDB_OSABI_UNKNOWN && nto_is_nto_target)
     return nto_is_nto_target (abfd);
-  return GDB_OSABI_UNKNOWN;
+  return osabi;
 }
 
 static const char *nto_thread_state_str[] =
@@ -396,7 +440,6 @@ nto_initialize_signals (void)
 #endif
 }
 
-
 /* Read AUXV from initial_stack.  */
 LONGEST
 nto_read_auxv_from_initial_stack (CORE_ADDR initial_stack, gdb_byte *readbuf,
@@ -480,4 +523,45 @@ nto_read_auxv_from_initial_stack (CORE_ADDR initial_stack, gdb_byte *readbuf,
   return len_read;
 }
 
+static struct nto_inferior_data *
+nto_new_inferior_data (void)
+{
+  struct nto_inferior_data *const inf_data
+    = XCNEW (struct nto_inferior_data);
+
+  return inf_data;
+}
+
+static void
+nto_inferior_data_cleanup (struct inferior *const inf, void *const dat)
+{
+  xfree (dat);
+}
+
+struct nto_inferior_data *
+nto_inferior_data (struct inferior *const inferior)
+{
+  struct inferior *const inf = inferior ? inferior : current_inferior ();
+  struct nto_inferior_data *inf_data;
+
+  gdb_assert (inf != NULL);
+
+  inf_data = inferior_data (inf, nto_inferior_data_reg);
+  if (inf_data == NULL)
+    {
+      set_inferior_data (inf, nto_inferior_data_reg,
+			 (inf_data = nto_new_inferior_data ()));
+    }
+
+  return inf_data;
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+extern initialize_file_ftype _initialize_nto_tdep;
 
+void
+_initialize_nto_tdep (void)
+{
+  nto_inferior_data_reg
+    = register_inferior_data_with_cleanup (NULL, nto_inferior_data_cleanup);
+}
diff --git a/gdb/nto-tdep.h b/gdb/nto-tdep.h
index 7089a12..6ed9da0 100644
--- a/gdb/nto-tdep.h
+++ b/gdb/nto-tdep.h
@@ -142,6 +142,16 @@ struct private_thread_info
   char name[1];
 };
 
+/* Per-inferior data, common for both procfs and remote.  */
+struct nto_inferior_data
+{
+  /* Last stopped flags result from wait function */
+  unsigned int stopped_flags;
+
+  /* Last known stopped PC */
+  CORE_ADDR stopped_pc;
+};
+
 /* Generic functions in nto-tdep.c.  */
 
 void nto_init_solib_absolute_prefix (void);
@@ -172,4 +182,6 @@ LONGEST nto_read_auxv_from_initial_stack (CORE_ADDR inital_stack,
 					  gdb_byte *readbuf,
 					  LONGEST len, size_t sizeof_auxv_t);
 
+struct nto_inferior_data *nto_inferior_data (struct inferior *inf);
+
 #endif
-- 
1.9.1