[PATCH 0/2] Remove two VECs

[PATCH 0/2] Remove two VECs

[Tom Tromey]

This series removes a couple more uses of VEC from gdb, replacing them
with std::vector.

I ran this through the buildbot, but I don't think it actually tests
any of this code, so extra scrutiny would be appreciated.

Tom

[PATCH 1/2] Remove a VEC from ppc-linux-nat.c

[Tom Tromey]

This replaces a VEC in ppc-linux-nat.c with a std::vector.

gdb/ChangeLog
2019-04-27  Tom Tromey  <tom@tromey.com>

	* ppc-linux-nat.c (thread_points_p): Remove typedef and DEF_VEC.
	(ppc_threads): Now a std::vector.  Now static.
	(hwdebug_find_thread_points_by_tid)
	(ppc_linux_nat_target::low_new_thread, ppc_linux_thread_exit):
	Update.
---
 gdb/ChangeLog       |  8 ++++++++
 gdb/ppc-linux-nat.c | 30 +++++++++++++-----------------
 2 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 628e3d5e8f6..45cf594ffca 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -1578,7 +1578,7 @@ struct hw_break_tuple
 /* This is an internal VEC created to store information about *points inserted
    for each thread.  This is used when PowerPC HWDEBUG ptrace interface is
    available.  */
-typedef struct thread_points
+struct thread_points
   {
     /* The TID to which this *point relates.  */
     int tid;
@@ -1589,10 +1589,9 @@ typedef struct thread_points
        size of these vector is MAX_SLOTS_NUMBER.  If the hw_break element of
        the tuple is NULL, then the position in the vector is free.  */
     struct hw_break_tuple *hw_breaks;
-  } *thread_points_p;
-DEF_VEC_P (thread_points_p);
+  };
 
-VEC(thread_points_p) *ppc_threads = NULL;
+static std::vector<thread_points *> ppc_threads;
 
 /* The version of the PowerPC HWDEBUG kernel interface that we will use, if
    available.  */
@@ -1758,14 +1757,11 @@ hwdebug_point_cmp (struct ppc_hw_breakpoint *a, struct ppc_hw_breakpoint *b)
 static struct thread_points *
 hwdebug_find_thread_points_by_tid (int tid, int alloc_new)
 {
-  int i;
-  struct thread_points *t;
-
-  for (i = 0; VEC_iterate (thread_points_p, ppc_threads, i, t); i++)
+  for (thread_points *t : ppc_threads)
     if (t->tid == tid)
       return t;
 
-  t = NULL;
+  struct thread_points *t = NULL;
 
   /* Do we need to allocate a new point_item
      if the wanted one does not exist?  */
@@ -1774,7 +1770,7 @@ hwdebug_find_thread_points_by_tid (int tid, int alloc_new)
       t = XNEW (struct thread_points);
       t->hw_breaks = XCNEWVEC (struct hw_break_tuple, max_slots_number);
       t->tid = tid;
-      VEC_safe_push (thread_points_p, ppc_threads, t);
+      ppc_threads.push_back (t);
     }
 
   return t;
@@ -2359,11 +2355,11 @@ ppc_linux_nat_target::low_new_thread (struct lwp_info *lp)
       struct thread_points *p;
       struct hw_break_tuple *hw_breaks;
 
-      if (VEC_empty (thread_points_p, ppc_threads))
+      if (ppc_threads.empty ())
 	return;
 
       /* Get a list of breakpoints from any thread.  */
-      p = VEC_last (thread_points_p, ppc_threads);
+      p = ppc_threads.last ();
       hw_breaks = p->hw_breaks;
 
       /* Copy that thread's breakpoints and watchpoints to the new thread.  */
@@ -2392,22 +2388,22 @@ ppc_linux_thread_exit (struct thread_info *tp, int silent)
   int i;
   int tid = tp->ptid.lwp ();
   struct hw_break_tuple *hw_breaks;
-  struct thread_points *t = NULL, *p;
+  struct thread_points *t = NULL;
 
   if (!have_ptrace_hwdebug_interface ())
     return;
 
-  for (i = 0; VEC_iterate (thread_points_p, ppc_threads, i, p); i++)
-    if (p->tid == tid)
+  for (i = 0; i < ppc_threads.size (); i++)
+    if (ppc_threads[i].tid == tid)
       {
-	t = p;
+	t = &ppc_threads[i];
 	break;
       }
 
   if (t == NULL)
     return;
 
-  VEC_unordered_remove (thread_points_p, ppc_threads, i);
+  unordered_remove (ppc_threads, i);
 
   hw_breaks = t->hw_breaks;
 
-- 
2.17.2

Re: [PATCH 1/2] Remove a VEC from ppc-linux-nat.c

[Simon Marchi]

Hi Tom,

LGTM, I just wrote some suggestions below.

On 2019-04-27 10:31 a.m., Tom Tromey wrote:
> @@ -1758,14 +1757,11 @@ hwdebug_point_cmp (struct ppc_hw_breakpoint *a, struct ppc_hw_breakpoint *b)
>  static struct thread_points *
>  hwdebug_find_thread_points_by_tid (int tid, int alloc_new)
>  {
> -  int i;
> -  struct thread_points *t;
> -
> -  for (i = 0; VEC_iterate (thread_points_p, ppc_threads, i, t); i++)
> +  for (thread_points *t : ppc_threads)
>      if (t->tid == tid)
>        return t;

Could you add braces to this for, to match our coding style?

> @@ -2392,22 +2388,22 @@ ppc_linux_thread_exit (struct thread_info *tp, int silent)
>    int i;
>    int tid = tp->ptid.lwp ();
>    struct hw_break_tuple *hw_breaks;
> -  struct thread_points *t = NULL, *p;
> +  struct thread_points *t = NULL;
>  
>    if (!have_ptrace_hwdebug_interface ())
>      return;
>  
> -  for (i = 0; VEC_iterate (thread_points_p, ppc_threads, i, p); i++)
> -    if (p->tid == tid)
> +  for (i = 0; i < ppc_threads.size (); i++)
> +    if (ppc_threads[i].tid == tid)
>        {
> -	t = p;
> +	t = &ppc_threads[i];
>  	break;
>        }

Here too?

I believe this loop could be a range-based one, though it also works like this.

Simon

Re: [PATCH 1/2] Remove a VEC from ppc-linux-nat.c

[Simon Marchi]

On 2019-04-27 11:23 a.m., Simon Marchi wrote:
> Hi Tom,
> 
> LGTM, I just wrote some suggestions below.
> 
> On 2019-04-27 10:31 a.m., Tom Tromey wrote:
>> @@ -1758,14 +1757,11 @@ hwdebug_point_cmp (struct ppc_hw_breakpoint *a, struct ppc_hw_breakpoint *b)
>>  static struct thread_points *
>>  hwdebug_find_thread_points_by_tid (int tid, int alloc_new)
>>  {
>> -  int i;
>> -  struct thread_points *t;
>> -
>> -  for (i = 0; VEC_iterate (thread_points_p, ppc_threads, i, t); i++)
>> +  for (thread_points *t : ppc_threads)
>>      if (t->tid == tid)
>>        return t;
> 
> Could you add braces to this for, to match our coding style?
> 
>> @@ -2392,22 +2388,22 @@ ppc_linux_thread_exit (struct thread_info *tp, int silent)
>>    int i;
>>    int tid = tp->ptid.lwp ();
>>    struct hw_break_tuple *hw_breaks;
>> -  struct thread_points *t = NULL, *p;
>> +  struct thread_points *t = NULL;
>>  
>>    if (!have_ptrace_hwdebug_interface ())
>>      return;
>>  
>> -  for (i = 0; VEC_iterate (thread_points_p, ppc_threads, i, p); i++)
>> -    if (p->tid == tid)
>> +  for (i = 0; i < ppc_threads.size (); i++)
>> +    if (ppc_threads[i].tid == tid)
>>        {
>> -	t = p;
>> +	t = &ppc_threads[i];
>>  	break;
>>        }
> 
> Here too?
> 
> I believe this loop could be a range-based one, though it also works like this.

Nevermind about this last suggestion, as the value of the `i` variable is required
below to do the removal.

But actually when looking at the code a bit closer, I am not sure it works, since
 ppc_threads[i] yields a pointer, so using the '.' operator is not valid.  And indeed:

/home/simark/src/binutils-gdb/gdb/ppc-linux-nat.c: In function 'void ppc_linux_thread_exit(thread_info*, int)':
/home/simark/src/binutils-gdb/gdb/ppc-linux-nat.c:2397:24: error: request for member 'tid' in 'ppc_threads.std::vector<_Tp, _Alloc>::operator[]<thread_points*, std::allocator<thread_points*> >(((std::vector<thread_points*>::size_type)i))', which is of pointer type '__gnu_cxx::__alloc_traits<std::allocator<thread_points*> >::value_type {aka thread_points*}' (maybe you meant to use '->' ?)
     if (ppc_threads[i].tid == tid)
                        ^~~
/home/simark/src/binutils-gdb/gdb/ppc-linux-nat.c:2399:20: error: cannot convert 'thread_points**' to 'thread_points*' in assignment
  t = &ppc_threads[i];
                    ^

Building also points out this error, where you probably meant to use .back ():

/home/simark/src/binutils-gdb/gdb/ppc-linux-nat.c: In member function 'virtual void ppc_linux_nat_target::low_new_thread(lwp_info*)':
/home/simark/src/binutils-gdb/gdb/ppc-linux-nat.c:2362:23: error: 'class std::vector<thread_points*>' has no member named 'last'; did you mean 'at'?
       p = ppc_threads.last ();
                       ^~~~

Applying this fixup to your patch makes it build for me:

From b687773f708d21e04dfe3b7d7094514d4cf8b7b7 Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@polymtl.ca>
Date: Sat, 27 Apr 2019 11:30:58 -0400
Subject: [PATCH] fixup

---
 gdb/ppc-linux-nat.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 45cf594ffcac..59e7ca5863f1 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -2359,7 +2359,7 @@ ppc_linux_nat_target::low_new_thread (struct lwp_info *lp)
 	return;

       /* Get a list of breakpoints from any thread.  */
-      p = ppc_threads.last ();
+      p = ppc_threads.back ();
       hw_breaks = p->hw_breaks;

       /* Copy that thread's breakpoints and watchpoints to the new thread.  */
@@ -2394,9 +2394,9 @@ ppc_linux_thread_exit (struct thread_info *tp, int silent)
     return;

   for (i = 0; i < ppc_threads.size (); i++)
-    if (ppc_threads[i].tid == tid)
+    if (ppc_threads[i]->tid == tid)
       {
-	t = &ppc_threads[i];
+	t = ppc_threads[i];
 	break;
       }

-- 
2.21.0

Re: [PATCH 1/2] Remove a VEC from ppc-linux-nat.c

[Tom Tromey]

>>>>> "Simon" == Simon Marchi <simark@simark.ca> writes:

Simon> Applying this fixup to your patch makes it build for me:

Thanks.  I've included this & made the other changes you requested.

Tom

[PATCH 2/2] Remove a VEC from aarch64-tdep.c

[Tom Tromey]

This removes a VEC from aarch64-tdep.c, replacing it with a
std::vector.

gdb/ChangeLog
2019-04-27  Tom Tromey  <tom@tromey.com>

	* aarch64-tdep.c (stack_item_t): Remove typedef and DEF_VEC.
	(struct aarch64_call_info): Add initializers.
	<si>: Now a std::vector.
	(pass_on_stack, aarch64_push_dummy_call): Update.
---
 gdb/ChangeLog      |  7 +++++++
 gdb/aarch64-tdep.c | 36 +++++++++++++++---------------------
 2 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index f8b4fa4c974..2c8c6a1bdc3 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -1206,7 +1206,7 @@ aarch64_execute_dwarf_cfa_vendor_op (struct gdbarch *gdbarch, gdb_byte op,
 /* When arguments must be pushed onto the stack, they go on in reverse
    order.  The code below implements a FILO (stack) to do this.  */
 
-typedef struct
+struct stack_item_t
 {
   /* Value to pass on stack.  It can be NULL if this item is for stack
      padding.  */
@@ -1214,9 +1214,7 @@ typedef struct
 
   /* Size in bytes of value to pass on stack.  */
   int len;
-} stack_item_t;
-
-DEF_VEC_O (stack_item_t);
+};
 
 /* Implement the gdbarch type alignment method, overrides the generic
    alignment algorithm for anything that is aarch64 specific.  */
@@ -1392,22 +1390,22 @@ aapcs_is_vfp_call_or_return_candidate (struct type *type, int *count,
 struct aarch64_call_info
 {
   /* the current argument number.  */
-  unsigned argnum;
+  unsigned argnum = 0;
 
   /* The next general purpose register number, equivalent to NGRN as
      described in the AArch64 Procedure Call Standard.  */
-  unsigned ngrn;
+  unsigned ngrn = 0;
 
   /* The next SIMD and floating point register number, equivalent to
      NSRN as described in the AArch64 Procedure Call Standard.  */
-  unsigned nsrn;
+  unsigned nsrn = 0;
 
   /* The next stacked argument address, equivalent to NSAA as
      described in the AArch64 Procedure Call Standard.  */
-  unsigned nsaa;
+  unsigned nsaa = 0;
 
   /* Stack item vector.  */
-  VEC(stack_item_t) *si;
+  std::vector<stack_item_t> si;
 };
 
 /* Pass a value in a sequence of consecutive X registers.  The caller
@@ -1521,7 +1519,7 @@ pass_on_stack (struct aarch64_call_info *info, struct type *type,
 
   item.len = len;
   item.data = buf;
-  VEC_safe_push (stack_item_t, info->si, &item);
+  info->si.push_back (item);
 
   info->nsaa += len;
   if (info->nsaa & (align - 1))
@@ -1532,7 +1530,7 @@ pass_on_stack (struct aarch64_call_info *info, struct type *type,
       item.len = pad;
       item.data = NULL;
 
-      VEC_safe_push (stack_item_t, info->si, &item);
+      info->si.push_back (item);
       info->nsaa += pad;
     }
 }
@@ -1632,8 +1630,6 @@ aarch64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int argnum;
   struct aarch64_call_info info;
 
-  memset (&info, 0, sizeof (info));
-
   /* We need to know what the type of the called function is in order
      to determine the number of named/anonymous arguments for the
      actual argument placement, and the return type in order to handle
@@ -1762,18 +1758,16 @@ aarch64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   if (info.nsaa & 15)
     sp -= 16 - (info.nsaa & 15);
 
-  while (!VEC_empty (stack_item_t, info.si))
+  while (!info.si.empty ())
     {
-      stack_item_t *si = VEC_last (stack_item_t, info.si);
+      const stack_item_t &si = info.si.back ();
 
-      sp -= si->len;
-      if (si->data != NULL)
-	write_memory (sp, si->data, si->len);
-      VEC_pop (stack_item_t, info.si);
+      sp -= si.len;
+      if (si.data != NULL)
+	write_memory (sp, si.data, si.len);
+      info.si.pop_back ();
     }
 
-  VEC_free (stack_item_t, info.si);
-
   /* Finally, update the SP register.  */
   regcache_cooked_write_unsigned (regcache, AARCH64_SP_REGNUM, sp);
 
-- 
2.17.2

Re: [PATCH 2/2] Remove a VEC from aarch64-tdep.c

[Simon Marchi]

On 2019-04-27 10:31 a.m., Tom Tromey wrote:
> This removes a VEC from aarch64-tdep.c, replacing it with a
> std::vector.

This LGTM, thanks.

Simon