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, 7 insertions, 6 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index c0c6f51..7eef2c5 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,8 @@
+2019-10-02  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* linux-low.c (linux_low_read_btrace): Update for change to
+	std::vector.
+
 2019-09-20  Christian Biesinger  <cbiesinger@google.com>
 
 	* debug.c (debug_threads): Remove comment in favor of the header.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index d64c364..0e4b14e 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -7115,9 +7115,7 @@ linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer,
 		       enum btrace_read_type type)
 {
   struct btrace_data btrace;
-  struct btrace_block *block;
   enum btrace_error err;
-  int i;
 
   err = linux_read_btrace (&btrace, tinfo, type);
   if (err != BTRACE_ERR_NONE)
@@ -7140,11 +7138,9 @@ linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer,
       buffer_grow_str (buffer, "<!DOCTYPE btrace SYSTEM \"btrace.dtd\">\n");
       buffer_grow_str (buffer, "<btrace version=\"1.0\">\n");
 
-      for (i = 0;
-	   VEC_iterate (btrace_block_s, btrace.variant.bts.blocks, i, block);
-	   i++)
+      for (const btrace_block &block : *btrace.variant.bts.blocks)
 	buffer_xml_printf (buffer, "<block begin=\"0x%s\" end=\"0x%s\"/>\n",
-			   paddress (block->begin), paddress (block->end));
+			   paddress (block.begin), paddress (block.end));
 
       buffer_grow_str0 (buffer, "</btrace>\n");
       break;