Class-fy dwarf2_frame_state

This patch adds ctor and dtor to dwarf2_frame_state, so that we can
remove one cleanup "old_chain".

gdb:

2017-08-11  Yao Qi  <yao.qi@linaro.org>

	* dwarf2-frame.c (dwarf2_frame_state_free): Remove.
	(dwarf2_frame_state::dwarf2_frame_state): New.
	(dwarf2_frame_state::~dwarf2_frame_state): New.
	(dwarf2_fetch_cfa_info): Update.
	(dwarf2_frame_cache): Remove old_chain.  Change 'fs' to an object
	rather than a pointer.  Update code.
	* dwarf2-frame.h (struct dwarf2_frame_state): Declare ctor and
	dtor.
	<data_align, code_align, retaddr_column>: Change them to const.
	<armcc_cfa_offsets_sf, armcc_cfa_offsets_reversed>: Change them
	to bool.

1 files changed, 12 insertions, 7 deletions

diff --git a/gdb/dwarf2-frame.h b/gdb/dwarf2-frame.h
index 69a7a20..c952a20 100644
--- a/gdb/dwarf2-frame.h
+++ b/gdb/dwarf2-frame.h
@@ -106,35 +106,40 @@ struct dwarf2_frame_state_reg_info
   struct dwarf2_frame_state_reg_info *prev;
 };
 
+struct dwarf2_cie;
+
 /* Structure describing a frame state.  */
 
 struct dwarf2_frame_state
 {
+  dwarf2_frame_state (CORE_ADDR pc, struct dwarf2_cie *cie);
+  ~dwarf2_frame_state ();
+
   /* Each register save state can be described in terms of a CFA slot,
      another register, or a location expression.  */
-  struct dwarf2_frame_state_reg_info regs;
+  struct dwarf2_frame_state_reg_info regs {};
 
   /* The PC described by the current frame state.  */
   CORE_ADDR pc;
 
   /* Initial register set from the CIE.
      Used to implement DW_CFA_restore.  */
-  struct dwarf2_frame_state_reg_info initial;
+  struct dwarf2_frame_state_reg_info initial {};
 
   /* The information we care about from the CIE.  */
-  LONGEST data_align;
-  ULONGEST code_align;
-  ULONGEST retaddr_column;
+  const LONGEST data_align;
+  const ULONGEST code_align;
+  const ULONGEST retaddr_column;
 
   /* Flags for known producer quirks.  */
 
   /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
      and DW_CFA_def_cfa_offset takes a factored offset.  */
-  int armcc_cfa_offsets_sf;
+  bool armcc_cfa_offsets_sf = false;
 
   /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
      the CFA is defined as REG - OFFSET rather than REG + OFFSET.  */
-  int armcc_cfa_offsets_reversed;
+  bool armcc_cfa_offsets_reversed = false;
 };
 
 /* Set the architecture-specific register state initialization