[PATCHv4 2/3] gdb: Change a VEC to std::vector in btrace.{c,h}

Andrew Burgess
2019-09-26T11:41:24Z

Replace a VEC with a std::vector in btrace.h, and update btrace.c to
match. This code is currently untested, so I've been quite
conservative with the changes - where previously we used VEC_safe_push
which would allocate the vector if it isn't already allocated - I now
check and allocate the std::vector using 'new' before pushing to the
vector.

As the new vector is inside a union I've currently used a pointer to
vector, which makes the code slightly uglier than it might otherwise
be, but again, due to lack of testing I'm reluctant to start
refactoring the code in a big way.

gdb/ChangeLog:

* btrace.c (btrace_maint_clear): Update to handle change from VEC
to std::vector.
(btrace_maint_decode_pt): Likewise, and move allocation of the
vector outside of the loop.
(btrace_maint_update_packets): Update to handle change from VEC to
std::vector.
(btrace_maint_print_packets): Likewise.
(maint_info_btrace_cmd): Likewise.
* btrace.h: Remove 'vec.h' header include and use of DEF_VEC_O.
(typedef btrace_pt_packet_s): Delete.
(struct btrace_maint_info) <packets>: Change fromm VEC to
std::vector.
---
gdb/ChangeLog | 15 +++++++++++++++
gdb/btrace.c | 40 +++++++++++++++++++++-------------------
gdb/btrace.h | 6 +-----
3 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/gdb/btrace.c b/gdb/btrace.c
index 006cd740554..9fc95a35739 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -1825,7 +1825,7 @@ btrace_maint_clear (struct btrace_thread_info *btinfo)

#if defined (HAVE_LIBIPT)
case BTRACE_FORMAT_PT:
- xfree (btinfo->maint.variant.pt.packets);
+ delete btinfo->maint.variant.pt.packets;

btinfo->maint.variant.pt.packets = NULL;
btinfo->maint.variant.pt.packet_history.begin = 0;
@@ -2962,6 +2962,9 @@ btrace_maint_decode_pt (struct btrace_maint_info *maint,
{
int errcode;

+ if (maint->variant.pt.packets == NULL)
+ maint->variant.pt.packets = new std::vector <btrace_pt_packet>;
+
for (;;)
{
struct btrace_pt_packet packet;
@@ -2982,8 +2985,7 @@ btrace_maint_decode_pt (struct btrace_maint_info *maint,
if (maint_btrace_pt_skip_pad == 0 || packet.packet.type != ppt_pad)
{
packet.errcode = pt_errcode (errcode);
- VEC_safe_push (btrace_pt_packet_s, maint->variant.pt.packets,
- &packet);
+ maint->variant.pt.packets->push_back (packet);
}
}

@@ -2991,8 +2993,7 @@ btrace_maint_decode_pt (struct btrace_maint_info *maint,
break;

packet.errcode = pt_errcode (errcode);
- VEC_safe_push (btrace_pt_packet_s, maint->variant.pt.packets,
- &packet);
+ maint->variant.pt.packets->push_back (packet);

warning (_("Error at trace offset 0x%" PRIx64 ": %s."),
packet.offset, pt_errstr (packet.errcode));
@@ -3093,11 +3094,14 @@ btrace_maint_update_packets (struct btrace_thread_info *btinfo,

#if defined (HAVE_LIBIPT)
case BTRACE_FORMAT_PT:
- if (VEC_empty (btrace_pt_packet_s, btinfo->maint.variant.pt.packets))
+ if (btinfo->maint.variant.pt.packets == nullptr)
+ btinfo->maint.variant.pt.packets = new std::vector <btrace_pt_packet>;
+
+ if (btinfo->maint.variant.pt.packets->empty ())
btrace_maint_update_pt_packets (btinfo);

*begin = 0;
- *end = VEC_length (btrace_pt_packet_s, btinfo->maint.variant.pt.packets);
+ *end = btinfo->maint.variant.pt.packets->size ();
*from = btinfo->maint.variant.pt.packet_history.begin;
*to = btinfo->maint.variant.pt.packet_history.end;
break;
@@ -3140,23 +3144,21 @@ btrace_maint_print_packets (struct btrace_thread_info *btinfo,
#if defined (HAVE_LIBIPT)
case BTRACE_FORMAT_PT:
{
- VEC (btrace_pt_packet_s) *packets;
+ const std::vector <btrace_pt_packet> &packets
+ = *btinfo->maint.variant.pt.packets;
unsigned int pkt;

- packets = btinfo->maint.variant.pt.packets;
for (pkt = begin; pkt < end; ++pkt)
{
- const struct btrace_pt_packet *packet;
-
- packet = VEC_index (btrace_pt_packet_s, packets, pkt);
+ const struct btrace_pt_packet &packet = packets.at (pkt);

printf_unfiltered ("%u\t", pkt);
- printf_unfiltered ("0x%" PRIx64 "\t", packet->offset);
+ printf_unfiltered ("0x%" PRIx64 "\t", packet.offset);

- if (packet->errcode == pte_ok)
- pt_print_packet (&packet->packet);
+ if (packet.errcode == pte_ok)
+ pt_print_packet (&packet.packet);
else
- printf_unfiltered ("[error: %s]", pt_errstr (packet->errcode));
+ printf_unfiltered ("[error: %s]", pt_errstr (packet.errcode));

printf_unfiltered ("\n");
}
@@ -3447,9 +3449,9 @@ maint_info_btrace_cmd (const char *args, int from_tty)
version.ext != NULL ? version.ext : "");

btrace_maint_update_pt_packets (btinfo);
- printf_unfiltered (_("Number of packets: %u.\n"),
- VEC_length (btrace_pt_packet_s,
- btinfo->maint.variant.pt.packets));
+ printf_unfiltered (_("Number of packets: %zu.\n"),
+ ((btinfo->maint.variant.pt.packets == nullptr)
+ ? 0 : btinfo->maint.variant.pt.packets->size ()));
}
break;
#endif /* defined (HAVE_LIBIPT) */
diff --git a/gdb/btrace.h b/gdb/btrace.h
index d09c424804b..208c089fa7c 100644
--- a/gdb/btrace.h
+++ b/gdb/btrace.h
@@ -29,7 +29,6 @@
#include "gdbsupport/btrace-common.h"
#include "target/waitstatus.h" /* For enum target_stop_reason. */
#include "gdbsupport/enum-flags.h"
-#include "gdbsupport/vec.h"

#if defined (HAVE_LIBIPT)
# include <intel-pt.h>
@@ -265,9 +264,6 @@ struct btrace_pt_packet
struct pt_packet packet;
};

-/* Define functions operating on a vector of packets. */
-typedef struct btrace_pt_packet btrace_pt_packet_s;
-DEF_VEC_O (btrace_pt_packet_s);
#endif /* defined (HAVE_LIBIPT) */

/* Branch trace iteration state for "maintenance btrace packet-history". */
@@ -301,7 +297,7 @@ struct btrace_maint_info
struct
{
/* A vector of decoded packets. */
- VEC (btrace_pt_packet_s) *packets;
+ std::vector <btrace_pt_packet> *packets;

/* The packet history iterator.
We are iterating over the above PACKETS vector. */
--
2.14.5