gdb: Remove a VEC from gdbsupport/btrace-common.h

Converts a VEC into a std::vector in gdbsupport/btrace-common.h.  This
commit just performs a mechanical conversion and doesn't do any
refactoring.  One consequence of this is that the std::vector must
actually be a pointer to std::vector as it is placed within a union.
It might be possible in future to refactor to a class hierarchy and
remove the need for a union, but I'd rather have that be a separate
change to make it easier to see the evolution of the code.

gdb/ChangeLog:

	* btrace.c (btrace_compute_ftrace_bts): Update for std::vector,
	make accesses into the vector constant references.
	(btrace_add_pc): Update for std::vector.
	(btrace_stitch_bts): Likewise.
	(parse_xml_btrace_block): Likewise.
	(btrace_maint_update_packets): Likewise.
	(btrace_maint_print_packets): Likewise.
	(maint_info_btrace_cmd): Likewise.
	* gdbsupport/btrace-common.c (btrace_data::fini): Update for
	std::vector.
	(btrace_data::empty): Likewise.
	(btrace_data_append): Likewise.
	* gdbsupport/btrace-common.h: Remove use of DEF_VEC_O.
	(typedef btrace_block_s): Delete.
	(struct btrace_block): Add constructor.
	(struct btrace_data_bts) <blocks>: Change to std::vector.
	* nat/linux-btrace.c (perf_event_read_bts): Update for
	std::vector.
	(linux_read_bts): Likewise.

gdb/gdbserver/ChangeLog:

	* linux-low.c (linux_low_read_btrace): Update for change to
	std::vector.

2 files changed, 19 insertions, 16 deletions

diff --git a/gdb/gdbsupport/btrace-common.c b/gdb/gdbsupport/btrace-common.c
index 13f1f1a..d6d3ab5 100644
--- a/gdb/gdbsupport/btrace-common.c
+++ b/gdb/gdbsupport/btrace-common.c
@@ -73,7 +73,8 @@ btrace_data::fini ()
       return;
 
     case BTRACE_FORMAT_BTS:
-      VEC_free (btrace_block_s, variant.bts.blocks);
+      delete variant.bts.blocks;
+      variant.bts.blocks = nullptr;
       return;
 
     case BTRACE_FORMAT_PT:
@@ -95,7 +96,7 @@ btrace_data::empty () const
       return true;
 
     case BTRACE_FORMAT_BTS:
-      return VEC_empty (btrace_block_s, variant.bts.blocks);
+      return variant.bts.blocks->empty ();
 
     case BTRACE_FORMAT_PT:
       return (variant.pt.size == 0);
@@ -132,7 +133,7 @@ btrace_data_append (struct btrace_data *dst,
 
 	case BTRACE_FORMAT_NONE:
 	  dst->format = BTRACE_FORMAT_BTS;
-	  dst->variant.bts.blocks = NULL;
+	  dst->variant.bts.blocks = new std::vector <btrace_block>;
 
 	  /* Fall-through.  */
 	case BTRACE_FORMAT_BTS:
@@ -141,15 +142,12 @@ btrace_data_append (struct btrace_data *dst,
 
 	    /* We copy blocks in reverse order to have the oldest block at
 	       index zero.  */
-	    blk = VEC_length (btrace_block_s, src->variant.bts.blocks);
+	    blk = src->variant.bts.blocks->size ();
 	    while (blk != 0)
 	      {
-		btrace_block_s *block;
-
-		block = VEC_index (btrace_block_s, src->variant.bts.blocks,
-				   --blk);
-
-		VEC_safe_push (btrace_block_s, dst->variant.bts.blocks, block);
+		const btrace_block &block
+		  = src->variant.bts.blocks->at (--blk);
+		dst->variant.bts.blocks->push_back (block);
 	      }
 	  }
 	}
diff --git a/gdb/gdbsupport/btrace-common.h b/gdb/gdbsupport/btrace-common.h
index 0b18924..9c57645 100644
--- a/gdb/gdbsupport/btrace-common.h
+++ b/gdb/gdbsupport/btrace-common.h
@@ -43,11 +43,15 @@ struct btrace_block
 
   /* The address of the first byte of the last instruction in the block.  */
   CORE_ADDR end;
-};
 
-/* Define functions operating on a vector of branch trace blocks.  */
-typedef struct btrace_block btrace_block_s;
-DEF_VEC_O (btrace_block_s);
+  /* Simple constructor.  */
+  btrace_block (CORE_ADDR begin, CORE_ADDR end)
+    : begin (begin),
+      end (end)
+  {
+    /* Nothing.  */
+  }
+};
 
 /* Enumeration of btrace formats.  */
 
@@ -137,8 +141,9 @@ struct btrace_config
 struct btrace_data_bts
 {
   /* Branch trace is represented as a vector of branch trace blocks starting
-     with the most recent block.  */
-  VEC (btrace_block_s) *blocks;
+     with the most recent block.  This needs to be a pointer as we place
+     btrace_data_bts into a union.  */
+  std::vector <btrace_block> *blocks;
 };
 
 /* Configuration information to go with the trace data.  */