[gdb] Fix grammar in comments and docs

Fix grammar in some comments and docs:
- machines that doesn't -> machines that don't
- its a -> it's a
- its the -> it's the
- if does its not -> if it does it's not
- one more instructions if doesn't match ->
  one more instruction if it doesn't match
- it's own -> its own
- it's first -> its first
- it's pointer -> its pointer

I also came across "it's performance" in gdb/stubs/*-stub.c in the HP public
domain notice, I've left that alone.

Tested on x86_64-linux.

gdb/amd64-tdep.c

@@ -1750,7 +1750,7 @@ amd64_displaced_step_fixup (struct gdbarch *gdbarch,
 	 system calls.	*/
       if (amd64_syscall_p (insn_details, &insn_len)
 	  /* GDB can get control back after the insn after the syscall.
-	     Presumably this is a kernel bug.  Fixup ensures its a nop, we
+	     Presumably this is a kernel bug.  Fixup ensures it's a nop, we
 	     add one to the length for it.  */
 	  && (pc < to || pc > (to + insn_len + 1)))
 	displaced_debug_printf ("syscall changed %%rip; not relocating");

gdb/doc/stabs.texinfo

@@ -3971,7 +3971,7 @@ symbols of file scope.  This is true for default, @samp{-ansi} and
 
 @item
 What ends the procedure scope?  Is it the proc block's @code{N_RBRAC} or the
-next @code{N_FUN}?  (I believe its the first.)
+next @code{N_FUN}?  (I believe it's the first.)
 @end itemize
 
 @node Stab Sections

gdb/gdbarch-gen.h

@@ -574,7 +574,7 @@ extern void set_gdbarch_memory_remove_breakpoint (struct gdbarch *gdbarch, gdbar
 extern CORE_ADDR gdbarch_decr_pc_after_break (struct gdbarch *gdbarch);
 extern void set_gdbarch_decr_pc_after_break (struct gdbarch *gdbarch, CORE_ADDR decr_pc_after_break);
 
-/* A function can be addressed by either it's "pointer" (possibly a
+/* A function can be addressed by either its "pointer" (possibly a
    descriptor address) or "entry point" (first executable instruction).
    The method "convert_from_func_ptr_addr" converting the former to the
    latter.  gdbarch_deprecated_function_start_offset is being used to implement

gdb/gdbarch_components.py

@@ -1072,7 +1072,7 @@
 
 Value(
     comment="""
-A function can be addressed by either it's "pointer" (possibly a
+A function can be addressed by either its "pointer" (possibly a
 descriptor address) or "entry point" (first executable instruction).
 The method "convert_from_func_ptr_addr" converting the former to the
 latter.  gdbarch_deprecated_function_start_offset is being used to implement

gdb/i386-tdep.c

@@ -913,7 +913,7 @@ i386_displaced_step_fixup (struct gdbarch *gdbarch,
 	  && pc != to + (insn - insn_start) + insn_len
 	  /* GDB can get control back after the insn after the syscall.
 	     Presumably this is a kernel bug.
-	     i386_displaced_step_copy_insn ensures its a nop,
+	     i386_displaced_step_copy_insn ensures it's a nop,
 	     we add one to the length for it.  */
 	  && pc != to + (insn - insn_start) + insn_len + 1)
 	displaced_debug_printf ("syscall changed %%eip; not relocating");

gdb/or1k-tdep.c

@@ -360,7 +360,7 @@ or1k_delay_slot_p (struct gdbarch *gdbarch, CORE_ADDR pc)
 			   NULL, 32, &tmp_fields, 0);
 
   /* NULL here would mean the last instruction was not understood by cgen.
-     This should not usually happen, but if does its not a delay slot.  */
+     This should not usually happen, but if it does it's not a delay slot.  */
   if (insn == NULL)
     return 0;
 

gdb/ppc-linux-nat.c

@@ -2126,7 +2126,7 @@ ppc_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
 	  /* DAWR interface allows to watch up to 512 byte wide ranges.  */
 	  region_size = 512;
 	  /* DAWR interface allows to watch up to 512 byte wide ranges which
-	     can't cross a 512 byte boundary on machines that doesn't have a
+	     can't cross a 512 byte boundary on machines that don't have a
 	     second DAWR (P9 or less).  */
 	  if (!(hwdebug_info.features & PPC_DEBUG_FEATURE_DATA_BP_ARCH_31))
 	    region_align = 512;

gdb/ppc64-tdep.c

@@ -688,7 +688,7 @@ ppc64_skip_trampoline_code_1 (frame_info_ptr frame, CORE_ADDR pc)
 	pc = ppc64_standard_linkage1_target (frame, insns);
       else
 	{
-	  /* Scan backward one more instructions if doesn't match.  */
+	  /* Scan backward one more instruction if it doesn't match.  */
 	  pc -= 4;
 	  continue;
 	}

gdb/solib-dsbt.c

@@ -853,7 +853,7 @@ dsbt_relocate_main_executable (void)
 }
 
 /* When gdb starts up the inferior, it nurses it along (through the
-   shell) until it is ready to execute it's first instruction.  At this
+   shell) until it is ready to execute its first instruction.  At this
    point, this function gets called via solib_create_inferior_hook.
 
    For the DSBT shared library, the main executable needs to be relocated.

gdb/solib-svr4.c

@@ -2312,7 +2312,7 @@ svr4_create_solib_event_breakpoints (svr4_info *info, struct gdbarch *gdbarch,
    set to 1.  When the dynamic linker sees this flag set, it will set
    a breakpoint at a location known only to itself, after saving the
    original contents of that place and the breakpoint address itself,
-   in it's own internal structures.  When we resume the inferior, it
+   in its own internal structures.  When we resume the inferior, it
    will eventually take a SIGTRAP when it runs into the breakpoint.
    We handle this (in a different place) by restoring the contents of
    the breakpointed location (which is only known after it stops),

gdb/stubs/i386-stub.c

@@ -46,7 +46,7 @@
  *
  *  Because gdb will sometimes write to the stack area to execute function
  *  calls, this program cannot rely on using the supervisor stack so it
- *  uses it's own stack area reserved in the int array remcomStack.
+ *  uses its own stack area reserved in the int array remcomStack.
  *
  *************
  *

gdb/stubs/m32r-stub.c

@@ -46,7 +46,7 @@
  *
  *  Because gdb will sometimes write to the stack area to execute function
  *  calls, this program cannot rely on using the supervisor stack so it
- *  uses it's own stack area reserved in the int array remcomStack.
+ *  uses its own stack area reserved in the int array remcomStack.
  *
  *************
  *

gdb/stubs/m68k-stub.c

@@ -62,7 +62,7 @@
  * 
  *  Because gdb will sometimes write to the stack area to execute function
  *  calls, this program cannot rely on using the supervisor stack so it
- *  uses it's own stack area reserved in the int array remcomStack.  
+ *  uses its own stack area reserved in the int array remcomStack.
  * 
  *************
  *

gdb/testsuite/gdb.base/coremaker.c

@@ -45,7 +45,7 @@ int coremaker_data = 1;	/* In Data section */
 int coremaker_bss;	/* In BSS section */
 
 /* Place a chunk of memory before coremaker_ro to improve the chances
-   that coremaker_ro will end up on it's own page.  See:
+   that coremaker_ro will end up on its own page.  See:
 
    https://sourceware.org/pipermail/gdb-patches/2020-May/168168.html
    https://sourceware.org/pipermail/gdb-patches/2020-May/168170.html  */

gdb/testsuite/gdb.mi/mi-exec-run.exp

@@ -62,7 +62,7 @@ proc test {inftty_mode mi_mode force_fail} {
     }
 
     if {$force_fail} {
-	# Disable the shell so that its the first exec that fails,
+	# Disable the shell so that it's the first exec that fails,
 	# instead of the shell starting and then failing with some
 	# unspecified output.
 	mi_gdb_test "-gdb-set startup-with-shell off" ".*"

gdb/testsuite/lib/mi-support.exp

@@ -201,7 +201,7 @@ proc mi_gdb_start_separate_mi_tty { { flags {} } } {
 # FLAGS is a list of flags, each flag is a string.
 #
 # If "separate-inferior-tty" is specified, the inferior works with
-# it's own PTY.
+# its own PTY.
 #
 # If "separate-mi-tty" is specified, the gdb starts in CLI mode, with
 # MI running on a secondary UI, on its own tty.