[PATCHv2 2/4] gdb: Remove more targets unwind_pc methods

[Andrew Burgess <andrew.burgess@embecosm.com>]

This commit rewrites default_unwind_pc to avoid short cutting the
steps of uninding the pc.  The new version of default_unwind_pc
contains calls to extract_typed_address (which wraps
gdbarch_pointer_to_address) and gdbarch_addr_bits_remove.  Targets
that don't override these methods will get the same behaviour as they
did before, but targets that do use these methods (and so need to call
them while unwinding the pc) can now use the default_unwind_pc method.

gdb/ChangeLog:

	* arm-tdep.c (arm_unwind_pc): Delete.
	(arm_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
	* frame-unwind.c (default_unwind_pc): Rewrite to call
	extract_typed_address and gdbarch_addr_bits_remove.
	* i386-tdep.c (i386_unwind_pc): Delete.
	(i386_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
	* m68k-tdep.c (m68k_unwind_pc): Delete.
	(m68k_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
	* m88k-tdep.c (m88k_unwind_pc): Delete.
	(m88k_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
	* nios2-tdep.c (nios2_unwind_pc): Delete.
	(nios2_get_next_pc): Update to call gdbarch_unwind_pc.
	(nios2_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
	* rl78-tdep.c (rl78_unwind_pc): Delete.
	(rl78_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
	* s390-tdep.c (s390_unwind_pc): Delete.
	(s390_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
	* tic6x-tdep.c (tic6x_unwind_pc): Delete.
	(tic6x_gdbarch_init): Delete use of set_gdbarch_unwind_pc.
---
 gdb/ChangeLog      | 22 ++++++++++++++++++++++
 gdb/arm-tdep.c     | 13 -------------
 gdb/frame-unwind.c | 16 ++++++++++++++--
 gdb/i386-tdep.c    | 13 -------------
 gdb/m68k-tdep.c    | 10 ----------
 gdb/m88k-tdep.c    | 11 -----------
 gdb/nios2-tdep.c   | 14 +-------------
 gdb/rl78-tdep.c    | 11 -----------
 gdb/s390-tdep.c    | 12 ------------
 gdb/tic6x-tdep.c   | 12 ------------
 10 files changed, 37 insertions(+), 97 deletions(-)

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 539ee756e1b..98efc454044 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -3069,18 +3069,6 @@ arm_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
 			 get_frame_pc (this_frame));
 }
 
-/* Given THIS_FRAME, find the previous frame's resume PC (which will
-   be used to construct the previous frame's ID, after looking up the
-   containing function).  */
-
-static CORE_ADDR
-arm_unwind_pc (struct gdbarch *gdbarch, struct frame_info *this_frame)
-{
-  CORE_ADDR pc;
-  pc = frame_unwind_register_unsigned (this_frame, ARM_PC_REGNUM);
-  return arm_addr_bits_remove (gdbarch, pc);
-}
-
 static CORE_ADDR
 arm_unwind_sp (struct gdbarch *gdbarch, struct frame_info *this_frame)
 {
@@ -9364,7 +9352,6 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* Frame handling.  */
   set_gdbarch_dummy_id (gdbarch, arm_dummy_id);
-  set_gdbarch_unwind_pc (gdbarch, arm_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, arm_unwind_sp);
 
   frame_base_set_default (gdbarch, &arm_normal_base);
diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c
index 0eed572ebbb..052998a1c4d 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -198,8 +198,20 @@ default_frame_unwind_stop_reason (struct frame_info *this_frame,
 CORE_ADDR
 default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
 {
-  int pc_regnum = gdbarch_pc_regnum (gdbarch);
-  return frame_unwind_register_unsigned (next_frame, pc_regnum);
+  struct type *type;
+  int pc_regnum;
+  CORE_ADDR addr;
+  struct value *value;
+
+  pc_regnum = gdbarch_pc_regnum (gdbarch);
+  value = frame_unwind_register_value (next_frame, pc_regnum);
+  type = builtin_type (gdbarch)->builtin_func_ptr;
+  addr = extract_typed_address (value_contents_all (value), type);
+  addr = gdbarch_addr_bits_remove (gdbarch, addr);
+
+  release_value (value);
+  value_free (value);
+  return addr;
 }
 
 /* Helper functions for value-based register unwinding.  These return
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 60dc8013a23..5b1276d678f 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -1954,17 +1954,6 @@ i386_skip_main_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 
   return pc;
 }
-
-/* This function is 64-bit safe.  */
-
-static CORE_ADDR
-i386_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
-{
-  gdb_byte buf[8];
-
-  frame_unwind_register (next_frame, gdbarch_pc_regnum (gdbarch), buf);
-  return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr);
-}
 \f
 
 /* Normal frames.  */
@@ -8486,8 +8475,6 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   set_gdbarch_dummy_id (gdbarch, i386_dummy_id);
 
-  set_gdbarch_unwind_pc (gdbarch, i386_unwind_pc);
-
   /* Add the i386 register groups.  */
   i386_add_reggroups (gdbarch);
   tdep->register_reggroup_p = i386_register_reggroup_p;
diff --git a/gdb/m68k-tdep.c b/gdb/m68k-tdep.c
index b9fa5e6d4cf..16bc16773ab 100644
--- a/gdb/m68k-tdep.c
+++ b/gdb/m68k-tdep.c
@@ -851,15 +851,6 @@ m68k_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
     return start_pc;
   return pc;
 }
-
-static CORE_ADDR
-m68k_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
-{
-  gdb_byte buf[8];
-
-  frame_unwind_register (next_frame, gdbarch_pc_regnum (gdbarch), buf);
-  return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr);
-}
 \f
 /* Normal frames.  */
 
@@ -1247,7 +1238,6 @@ m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* Frame unwinder.  */
   set_gdbarch_dummy_id (gdbarch, m68k_dummy_id);
-  set_gdbarch_unwind_pc (gdbarch, m68k_unwind_pc);
 
   /* Hook in the DWARF CFI frame unwinder.  */
   dwarf2_append_unwinders (gdbarch);
diff --git a/gdb/m88k-tdep.c b/gdb/m88k-tdep.c
index 6a50126548d..de5e1ffc325 100644
--- a/gdb/m88k-tdep.c
+++ b/gdb/m88k-tdep.c
@@ -103,15 +103,6 @@ constexpr gdb_byte m88k_break_insn[] = { 0xf0, 0x00, 0xd1, 0xff };
 
 typedef BP_MANIPULATION (m88k_break_insn) m88k_breakpoint;
 
-static CORE_ADDR
-m88k_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
-{
-  CORE_ADDR pc;
-
-  pc = frame_unwind_register_unsigned (next_frame, M88K_SXIP_REGNUM);
-  return m88k_addr_bits_remove (gdbarch, pc);
-}
-
 static void
 m88k_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
@@ -832,7 +823,6 @@ m88k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* Register numbers of various important registers.  */
   set_gdbarch_sp_regnum (gdbarch, M88K_R31_REGNUM);
-  set_gdbarch_pc_regnum (gdbarch, M88K_SXIP_REGNUM);
 
   /* Core file support.  */
   set_gdbarch_iterate_over_regset_sections
@@ -853,7 +843,6 @@ m88k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_addr_bits_remove (gdbarch, m88k_addr_bits_remove);
   set_gdbarch_breakpoint_kind_from_pc (gdbarch, m88k_breakpoint::kind_from_pc);
   set_gdbarch_sw_breakpoint_from_kind (gdbarch, m88k_breakpoint::bp_from_kind);
-  set_gdbarch_unwind_pc (gdbarch, m88k_unwind_pc);
   set_gdbarch_write_pc (gdbarch, m88k_write_pc);
 
   frame_base_set_default (gdbarch, &m88k_frame_base);
diff --git a/gdb/nios2-tdep.c b/gdb/nios2-tdep.c
index f6088f38ef5..3972dd9437d 100644
--- a/gdb/nios2-tdep.c
+++ b/gdb/nios2-tdep.c
@@ -1888,17 +1888,6 @@ nios2_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   return sp;
 }
 
-/* Implement the unwind_pc gdbarch method.  */
-
-static CORE_ADDR
-nios2_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
-{
-  gdb_byte buf[4];
-
-  frame_unwind_register (next_frame, NIOS2_PC_REGNUM, buf);
-  return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr);
-}
-
 /* Implement the unwind_sp gdbarch method.  */
 
 static CORE_ADDR
@@ -2186,7 +2175,7 @@ nios2_get_next_pc (struct regcache *regcache, CORE_ADDR pc)
       /* If ra is in the reglist, we have to use the value saved in the
 	 stack frame rather than the current value.  */
       if (uimm & (1 << NIOS2_RA_REGNUM))
-	pc = nios2_unwind_pc (gdbarch, get_current_frame ());
+	pc = gdbarch_unwind_pc (gdbarch, get_current_frame ());
       else
 	pc = regcache_raw_get_unsigned (regcache, NIOS2_RA_REGNUM);
     }
@@ -2322,7 +2311,6 @@ nios2_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_sw_breakpoint_from_kind (gdbarch, nios2_sw_breakpoint_from_kind);
 
   set_gdbarch_dummy_id (gdbarch, nios2_dummy_id);
-  set_gdbarch_unwind_pc (gdbarch, nios2_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, nios2_unwind_sp);
 
   /* The dwarf2 unwinder will normally produce the best results if
diff --git a/gdb/rl78-tdep.c b/gdb/rl78-tdep.c
index af6a0896082..46dd4f75f7b 100644
--- a/gdb/rl78-tdep.c
+++ b/gdb/rl78-tdep.c
@@ -1074,16 +1074,6 @@ rl78_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
   return p.prologue_end;
 }
 
-/* Implement the "unwind_pc" gdbarch method.  */
-
-static CORE_ADDR
-rl78_unwind_pc (struct gdbarch *arch, struct frame_info *next_frame)
-{
-  return rl78_addr_bits_remove
-           (arch, frame_unwind_register_unsigned (next_frame,
-	                                          RL78_PC_REGNUM));
-}
-
 /* Implement the "unwind_sp" gdbarch method.  */
 
 static CORE_ADDR
@@ -1468,7 +1458,6 @@ rl78_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   /* Frames, prologues, etc.  */
   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
   set_gdbarch_skip_prologue (gdbarch, rl78_skip_prologue);
-  set_gdbarch_unwind_pc (gdbarch, rl78_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, rl78_unwind_sp);
   set_gdbarch_frame_align (gdbarch, rl78_frame_align);
 
diff --git a/gdb/s390-tdep.c b/gdb/s390-tdep.c
index 408bb875d20..c1e17694a89 100644
--- a/gdb/s390-tdep.c
+++ b/gdb/s390-tdep.c
@@ -2129,17 +2129,6 @@ s390_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
   return 0;
 }
 
-/* Implement unwind_pc gdbarch method.  */
-
-static CORE_ADDR
-s390_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
-{
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-  ULONGEST pc;
-  pc = frame_unwind_register_unsigned (next_frame, tdep->pc_regnum);
-  return gdbarch_addr_bits_remove (gdbarch, pc);
-}
-
 /* Implement unwind_sp gdbarch method.  */
 
 static CORE_ADDR
@@ -7005,7 +6994,6 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   dwarf2_frame_set_init_reg (gdbarch, s390_dwarf2_frame_init_reg);
   dwarf2_frame_set_adjust_regnum (gdbarch, s390_adjust_frame_regnum);
   dwarf2_append_unwinders (gdbarch);
-  set_gdbarch_unwind_pc (gdbarch, s390_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, s390_unwind_sp);
 
   switch (info.bfd_arch_info->mach)
diff --git a/gdb/tic6x-tdep.c b/gdb/tic6x-tdep.c
index f11763d9925..f1aaaa3c36a 100644
--- a/gdb/tic6x-tdep.c
+++ b/gdb/tic6x-tdep.c
@@ -366,17 +366,6 @@ tic6x_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
     reg->how = DWARF2_FRAME_REG_UNDEFINED;
 }
 
-/* This is the implementation of gdbarch method unwind_pc.  */
-
-static CORE_ADDR
-tic6x_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
-{
-  gdb_byte buf[8];
-
-  frame_unwind_register (next_frame,  TIC6X_PC_REGNUM, buf);
-  return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr);
-}
-
 /* This is the implementation of gdbarch method unwind_sp.  */
 
 static CORE_ADDR
@@ -1290,7 +1279,6 @@ tic6x_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_sw_breakpoint_from_kind (gdbarch,
 				       tic6x_sw_breakpoint_from_kind);
 
-  set_gdbarch_unwind_pc (gdbarch, tic6x_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, tic6x_unwind_sp);
 
   /* Unwinding.  */
-- 
2.14.3