gdb/record: Refactor record history

This is the first step in a large refactor in how GDB keeps execution
history.  Rather than using a linked list where multiple entries can
describe a single instruction, the history will now be stored in an
std::deque, each instruction being one entry in the deque.

The choice was initially to use an std::vector, but it would become
unwieldy because it needs all the memory to be consecutive, which is
hard for 200 thousand entries. Deque was picked because it was a nice
midpoint between vector (maximum cache cohesion) and linked list
(maximum ease of finding space to store more).

Each instruction in memory will be now one record_full_instruction
entry, which for this commit just contains a vector of
record_full_entry for the effects of the instruction, and the data that
was stored in the record_full_end entry (that is, the instruction number
and the signal, if any).

This change introduced a minimal performance improvement (what's
important is that it isn't a degradation) and a  reduction in the total
memory footprint of roughly 20% if the entire history is used.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Reviewed-By: Christina Schimpe <christina.schimpe@intel.com>
Approved-By: Guinevere Larsen <guinevere@redhat.com>

gdb/aarch64-tdep.c

@@ -6319,8 +6319,6 @@ aarch64_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
 	       aarch64_record.aarch64_mems[rec_no].len))
 	    ret = -1;
 
-      if (record_full_arch_list_add_end ())
-	ret = -1;
     }
 
   deallocate_reg_mem (&aarch64_record);

gdb/amd64-linux-tdep.c

@@ -1591,9 +1591,6 @@ amd64_linux_record_signal (struct gdbarch *gdbarch,
 				     + AMD64_LINUX_frame_size))
     return -1;
 
-  if (record_full_arch_list_add_end ())
-    return -1;
-
   return 0;
 }
 

gdb/arm-tdep.c

@@ -14911,8 +14911,6 @@ arm_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
 	    }
 	}
 
-      if (record_full_arch_list_add_end ())
-	ret = -1;
     }
 
 

gdb/i386-linux-tdep.c

@@ -949,9 +949,6 @@ i386_linux_record_signal (struct gdbarch *gdbarch,
 				     I386_LINUX_xstate + I386_LINUX_frame_size))
     return -1;
 
-  if (record_full_arch_list_add_end ())
-    return -1;
-
   return 0;
 }
 

gdb/i386-tdep.c

@@ -5201,8 +5201,6 @@ i386_record_vex (struct i386_record_s *ir, uint8_t vex_w, uint8_t vex_r,
     }
 
   record_full_arch_list_add_reg (ir->regcache, ir->regmap[X86_RECORD_REIP_REGNUM]);
-  if (record_full_arch_list_add_end ())
-    return -1;
 
   return 0;
 }
@@ -8361,8 +8359,6 @@ reswitch_prefix_add:
 
   /* In the future, maybe still need to deal with need_dasm.  */
   I386_RECORD_FULL_ARCH_LIST_ADD_REG (X86_RECORD_REIP_REGNUM);
-  if (record_full_arch_list_add_end ())
-    return -1;
 
   return 0;
 

gdb/loongarch-tdep.c

@@ -2789,8 +2789,6 @@ loongarch_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
 					 LOONGARCH_PC_REGNUM))
 	return -1;
 
-      if (record_full_arch_list_add_end ())
-	return -1;
     }
 
   return ret;

gdb/moxie-tdep.c

@@ -1040,8 +1040,6 @@ moxie_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
 
   if (record_full_arch_list_add_reg (regcache, MOXIE_PC_REGNUM))
     return -1;
-  if (record_full_arch_list_add_end ())
-    return -1;
   return 0;
 }
 

gdb/ppc-linux-tdep.c

@@ -1565,9 +1565,6 @@ ppc_linux_record_signal (struct gdbarch *gdbarch, struct regcache *regcache,
   if (record_full_arch_list_add_mem (sp, SIGNAL_FRAMESIZE + sizeof_rt_sigframe))
     return -1;
 
-  if (record_full_arch_list_add_end ())
-    return -1;
-
   return 0;
 }
 

gdb/record-full.h

@@ -41,7 +41,6 @@ enum record_result
 
 extern int record_full_arch_list_add_reg (struct regcache *regcache, int num);
 extern int record_full_arch_list_add_mem (CORE_ADDR addr, int len);
-extern int record_full_arch_list_add_end (void);
 
 /* Returns true if the process record target is open.  */
 extern int record_full_is_used (void);

gdb/riscv-tdep.c

@@ -5468,8 +5468,5 @@ riscv_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
   if (res != RECORD_SUCCESS)
     return res;
 
-  if (record_full_arch_list_add_end ())
-    return -1;
-
   return 0;
 }

gdb/rs6000-tdep.c

@@ -7138,8 +7138,6 @@ UNKNOWN_PREFIX_OP:
   if (record_full_arch_list_add_reg (regcache, PPC_PC_REGNUM))
     return -1;
 
-  if (record_full_arch_list_add_end ())
-    return -1;
   return 0;
 }
 
@@ -7447,8 +7445,6 @@ UNKNOWN_OP:
 
   if (record_full_arch_list_add_reg (regcache, PPC_PC_REGNUM))
     return -1;
-  if (record_full_arch_list_add_end ())
-    return -1;
   return 0;
 }
 

gdb/s390-linux-tdep.c

@@ -912,9 +912,6 @@ s390_linux_record_signal (struct gdbarch *gdbarch, struct regcache *regcache,
   if (record_full_arch_list_add_mem (sp, sizeof_rt_sigframe))
     return -1;
 
-  if (record_full_arch_list_add_end ())
-    return -1;
-
   return 0;
 }
 

gdb/s390-tdep.c

@@ -7025,8 +7025,6 @@ UNKNOWN_OP:
 
   if (record_full_arch_list_add_reg (regcache, S390_PSWA_REGNUM))
     return -1;
-  if (record_full_arch_list_add_end ())
-    return -1;
   return 0;
 }