Change dwarf2_frame_state_reg_info::reg to be std::vector

This changes dwarf2_frame_state_reg_info::reg to be a std::vector.
This avoids passing NULL to memcpy in the copy constructor when the
original object does not have any registers.

gdb/ChangeLog
2018-10-03  Tom Tromey  <tom@tromey.com>

	* dwarf2-frame.h (dwarf2_frame_state_reg_info)
	<~dwarf2_frame_state_reg_info>: Update.
	<dwarf2_frame_state_reg_info>: Update.
	<alloc_regs>: Add assertion.  Update.
	<reg>: Now a std::vector.
	<num_regs>: Remove.
	<swap>: Update.
	* dwarf2-frame.c (dwarf2_restore_rule, execute_cfa_program)
	(execute_cfa_program_test, dwarf2_frame_cache): Update.

1 files changed, 14 insertions, 14 deletions

diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index f7dc820..118bc11 100644
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -204,14 +204,13 @@ dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
 {
   ULONGEST reg;
 
-  gdb_assert (fs->initial.reg);
   reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
   fs->regs.alloc_regs (reg + 1);
 
   /* Check if this register was explicitly initialized in the
   CIE initial instructions.  If not, default the rule to
   UNSPECIFIED.  */
-  if (reg < fs->initial.num_regs)
+  if (reg < fs->initial.reg.size ())
     fs->regs.reg[reg] = fs->initial.reg[reg];
   else
     fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
@@ -602,7 +601,7 @@ bad CFI data; mismatched DW_CFA_restore_state at %s"),
 	}
     }
 
-  if (fs->initial.reg == NULL)
+  if (fs->initial.reg.empty ())
     {
       /* Don't allow remember/restore between CIE and FDE programs.  */
       delete fs->regs.prev;
@@ -653,12 +652,12 @@ execute_cfa_program_test (struct gdbarch *gdbarch)
   auto r1 = dwarf2_frame_adjust_regnum (gdbarch, 1, fde.eh_frame_p);
   auto r2 = dwarf2_frame_adjust_regnum (gdbarch, 2, fde.eh_frame_p);
 
-  SELF_CHECK (fs.regs.num_regs == (std::max (r1, r2) + 1));
+  SELF_CHECK (fs.regs.reg.size () == (std::max (r1, r2) + 1));
 
   SELF_CHECK (fs.regs.reg[r2].how == DWARF2_FRAME_REG_SAVED_OFFSET);
   SELF_CHECK (fs.regs.reg[r2].loc.offset == -4);
 
-  for (auto i = 0; i < fs.regs.num_regs; i++)
+  for (auto i = 0; i < fs.regs.reg.size (); i++)
     if (i != r2)
       SELF_CHECK (fs.regs.reg[i].how == DWARF2_FRAME_REG_UNSPECIFIED);
 
@@ -1097,7 +1096,7 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
   {
     int column;		/* CFI speak for "register number".  */
 
-    for (column = 0; column < fs.regs.num_regs; column++)
+    for (column = 0; column < fs.regs.reg.size (); column++)
       {
 	/* Use the GDB register number as the destination index.  */
 	int regnum = dwarf_reg_to_regnum (gdbarch, column);
@@ -1140,8 +1139,9 @@ incomplete CFI data; unspecified registers (e.g., %s) at %s"),
 	if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
 	    || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
 	  {
-	    struct dwarf2_frame_state_reg *retaddr_reg =
-	      &fs.regs.reg[fs.retaddr_column];
+	    const std::vector<struct dwarf2_frame_state_reg> &regs
+	      = fs.regs.reg;
+	    ULONGEST retaddr_column = fs.retaddr_column;
 
 	    /* It seems rather bizarre to specify an "empty" column as
                the return adress column.  However, this is exactly
@@ -1150,14 +1150,14 @@ incomplete CFI data; unspecified registers (e.g., %s) at %s"),
                register corresponding to the return address column.
                Incidentally, that's how we should treat a return
                address column specifying "same value" too.  */
-	    if (fs.retaddr_column < fs.regs.num_regs
-		&& retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
-		&& retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
+	    if (fs.retaddr_column < fs.regs.reg.size ()
+		&& regs[retaddr_column].how != DWARF2_FRAME_REG_UNSPECIFIED
+		&& regs[retaddr_column].how != DWARF2_FRAME_REG_SAME_VALUE)
 	      {
 		if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
-		  cache->reg[regnum] = *retaddr_reg;
+		  cache->reg[regnum] = regs[retaddr_column];
 		else
-		  cache->retaddr_reg = *retaddr_reg;
+		  cache->retaddr_reg = regs[retaddr_column];
 	      }
 	    else
 	      {
@@ -1176,7 +1176,7 @@ incomplete CFI data; unspecified registers (e.g., %s) at %s"),
       }
   }
 
-  if (fs.retaddr_column < fs.regs.num_regs
+  if (fs.retaddr_column < fs.regs.reg.size ()
       && fs.regs.reg[fs.retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
     cache->undefined_retaddr = 1;