[PATCHv3 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.
	(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      | 20 ++++++++++++++++++++
 gdb/arm-tdep.c     | 13 -------------
 gdb/frame-unwind.c | 15 +++++++++++++--
 gdb/i386-tdep.c    | 13 -------------
 gdb/m68k-tdep.c    | 10 ----------
 gdb/nios2-tdep.c   | 14 +-------------
 gdb/rl78-tdep.c    | 11 -----------
 gdb/s390-tdep.c    | 12 ------------
 gdb/tic6x-tdep.c   | 12 ------------
 9 files changed, 34 insertions(+), 86 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9d316fbce98..5bf169ca02d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,23 @@
+2018-06-05  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* 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.
+	* 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.
+
 2018-06-05  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* aarch64-tdep.c (aarch64_unwind_pc): Deleted.
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 3ea0e79b739..45c5b36383a 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)
 {
@@ -9360,7 +9348,6 @@ 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..d5b20e4af73 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -198,8 +198,19 @@ 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);
+  return addr;
 }
 
 /* Helper functions for value-based register unwinding.  These return
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index b1d502f4827..8f443734a35 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -1955,17 +1955,6 @@ 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.  */
@@ -8501,8 +8490,6 @@ 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 a6e9b58a7d1..8d33bc2f661 100644
--- a/gdb/m68k-tdep.c
+++ b/gdb/m68k-tdep.c
@@ -850,15 +850,6 @@ 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.  */
 
@@ -1246,7 +1237,6 @@ 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/nios2-tdep.c b/gdb/nios2-tdep.c
index 91b4381f0b7..b6533d57719 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 ace01b1171a..70955d966fa 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 e4e08c706a1..f6b29380d10 100644
--- a/gdb/s390-tdep.c
+++ b/gdb/s390-tdep.c
@@ -2118,17 +2118,6 @@ 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
@@ -6996,7 +6985,6 @@ 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 efb8b0561b4..1d2671f155f 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
@@ -1284,7 +1273,6 @@ 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