Share code on to_xfer_partial for tfile and ctf target

In the to_xfer_partial implementations of ctf and tfile, the code on
reading from read-only sections is duplicated.  This patch moves it to
a separate function exec_read_partial_read_only.

gdb:

2014-02-23  Yao Qi  <yao@codesourcery.com>

	* ctf.c (ctf_xfer_partial): Move code to ...
	* exec.c (exec_read_partial_read_only): ... it.  New function.
	* tracefile-tfile.c (tfile_xfer_partial): Likewise.
	* tracefile.c: Include "exec.h".
	* exec.h (exec_read_partial_read_only): Declare.

6 files changed, 67 insertions, 76 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d7c3310..11b70b8 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,13 @@
 2014-02-23  Yao Qi  <yao@codesourcery.com>
 
+	* ctf.c (ctf_xfer_partial): Move code to ...
+	* exec.c (exec_read_partial_read_only): ... it.  New function.
+	* tracefile-tfile.c (tfile_xfer_partial): Likewise.
+	* tracefile.c: Include "exec.h".
+	* exec.h (exec_read_partial_read_only): Declare.
+
+2014-02-23  Yao Qi  <yao@codesourcery.com>
+
 	* tracefile-tfile.c (tfile_has_all_memory): Remove.
 	(tfile_has_memory): Remove.
 	(init_tfile_ops): Don't set fields to_has_all_memory and
diff --git a/gdb/ctf.c b/gdb/ctf.c
index 6924fb0..9c8f4d7 100644
--- a/gdb/ctf.c
+++ b/gdb/ctf.c
@@ -1467,47 +1467,7 @@ ctf_xfer_partial (struct target_ops *ops, enum target_object object,
       bt_iter_set_pos (bt_ctf_get_iter (ctf_iter), pos);
     }
 
-  /* It's unduly pedantic to refuse to look at the executable for
-     read-only pieces; so do the equivalent of readonly regions aka
-     QTro packet.  */
-  if (exec_bfd != NULL)
-    {
-      asection *s;
-      bfd_size_type size;
-      bfd_vma vma;
-
-      for (s = exec_bfd->sections; s; s = s->next)
-	{
-	  if ((s->flags & SEC_LOAD) == 0
-	      || (s->flags & SEC_READONLY) == 0)
-	    continue;
-
-	  vma = s->vma;
-	  size = bfd_get_section_size (s);
-	  if (vma <= offset && offset < (vma + size))
-	    {
-	      ULONGEST amt;
-
-	      amt = (vma + size) - offset;
-	      if (amt > len)
-		amt = len;
-
-	      amt = bfd_get_section_contents (exec_bfd, s,
-					      readbuf, offset - vma, amt);
-
-	      if (amt == 0)
-		return TARGET_XFER_EOF;
-	      else
-		{
-		  *xfered_len = amt;
-		  return TARGET_XFER_OK;
-		}
-	    }
-	}
-    }
-
-  /* Indicate failure to find the requested memory block.  */
-  return TARGET_XFER_E_IO;
+  return exec_read_partial_read_only (readbuf, offset, len, xfered_len);
 }
 
 /* This is the implementation of target_ops method
diff --git a/gdb/exec.c b/gdb/exec.c
index 7f53a50..74c61eb 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -530,6 +530,53 @@ remove_target_sections (void *owner)
 
 
 
+enum target_xfer_status
+exec_read_partial_read_only (gdb_byte *readbuf, ULONGEST offset,
+			     ULONGEST len, ULONGEST *xfered_len)
+{
+  /* It's unduly pedantic to refuse to look at the executable for
+     read-only pieces; so do the equivalent of readonly regions aka
+     QTro packet.  */
+  if (exec_bfd != NULL)
+    {
+      asection *s;
+      bfd_size_type size;
+      bfd_vma vma;
+
+      for (s = exec_bfd->sections; s; s = s->next)
+	{
+	  if ((s->flags & SEC_LOAD) == 0
+	      || (s->flags & SEC_READONLY) == 0)
+	    continue;
+
+	  vma = s->vma;
+	  size = bfd_get_section_size (s);
+	  if (vma <= offset && offset < (vma + size))
+	    {
+	      ULONGEST amt;
+
+	      amt = (vma + size) - offset;
+	      if (amt > len)
+		amt = len;
+
+	      amt = bfd_get_section_contents (exec_bfd, s,
+					      readbuf, offset - vma, amt);
+
+	      if (amt == 0)
+		return TARGET_XFER_EOF;
+	      else
+		{
+		  *xfered_len = amt;
+		  return TARGET_XFER_OK;
+		}
+	    }
+	}
+    }
+
+  /* Indicate failure to find the requested memory block.  */
+  return TARGET_XFER_E_IO;
+}
+
 VEC(mem_range_s) *
 section_table_available_memory (VEC(mem_range_s) *memory,
 				CORE_ADDR memaddr, ULONGEST len,
diff --git a/gdb/exec.h b/gdb/exec.h
index 4725f1b..960c585 100644
--- a/gdb/exec.h
+++ b/gdb/exec.h
@@ -46,6 +46,15 @@ extern int build_section_table (struct bfd *, struct target_section **,
 
 extern int resize_section_table (struct target_section_table *, int);
 
+/* Read from mappable read-only sections of BFD executable files.
+   Return TARGET_XFER_OK, if read is successful.  Return
+   TARGET_XFER_EOF if read is done.  Return TARGET_XFER_E_IO
+   otherwise.  */
+
+extern enum target_xfer_status
+  exec_read_partial_read_only (gdb_byte *readbuf, ULONGEST offset,
+			       ULONGEST len, ULONGEST *xfered_len);
+
 /* Appends all read-only memory ranges found in the target section
    table defined by SECTIONS and SECTIONS_END, starting at (and
    intersected with) MEMADDR for LEN bytes.  Returns the augmented
diff --git a/gdb/tracefile-tfile.c b/gdb/tracefile-tfile.c
index 3ef109e..02122eb 100644
--- a/gdb/tracefile-tfile.c
+++ b/gdb/tracefile-tfile.c
@@ -938,41 +938,7 @@ tfile_xfer_partial (struct target_ops *ops, enum target_object object,
 	}
     }
 
-  /* It's unduly pedantic to refuse to look at the executable for
-     read-only pieces; so do the equivalent of readonly regions aka
-     QTro packet.  */
-  /* FIXME account for relocation at some point.  */
-  if (exec_bfd)
-    {
-      asection *s;
-      bfd_size_type size;
-      bfd_vma vma;
-
-      for (s = exec_bfd->sections; s; s = s->next)
-	{
-	  if ((s->flags & SEC_LOAD) == 0
-	      || (s->flags & SEC_READONLY) == 0)
-	    continue;
-
-	  vma = s->vma;
-	  size = bfd_get_section_size (s);
-	  if (vma <= offset && offset < (vma + size))
-	    {
-	      ULONGEST amt;
-
-	      amt = (vma + size) - offset;
-	      if (amt > len)
-		amt = len;
-
-	      *xfered_len = bfd_get_section_contents (exec_bfd, s,
-						      readbuf, offset - vma, amt);
-	      return TARGET_XFER_OK;
-	    }
-	}
-    }
-
-  /* Indicate failure to find the requested memory block.  */
-  return TARGET_XFER_E_IO;
+  return exec_read_partial_read_only (readbuf, offset, len, xfered_len);
 }
 
 /* Iterate through the blocks of a trace frame, looking for a 'V'
diff --git a/gdb/tracefile.c b/gdb/tracefile.c
index 508f898..a7c3cf7 100644
--- a/gdb/tracefile.c
+++ b/gdb/tracefile.c
@@ -20,6 +20,7 @@
 #include "defs.h"
 #include "tracefile.h"
 #include "ctf.h"
+#include "exec.h"
 
 /* Helper macros.  */