Add entry in the command guide for --exclude-pagezero option.

Add test for 32 bit  __PAGEZERO segment.

Author: rjmansfield

llvm/docs/CommandGuide/llvm-size.rst

@@ -41,6 +41,13 @@ OPTIONS
  as a separate section entry for ``sysv`` output. If not specified, these
  symbols are ignored.
 
+.. option:: --exclude-pagezero
+
+ Do not include the ``__PAGEZERO`` segment when calculating size information
+ for Mach-O files. ``__PAGEZERO`` segment is a virtual memory region used
+ for memory protection that does not contribute to actual size, and excluding
+ can provide a better representation of actual size.
+
 .. option:: -d
 
  Equivalent to :option:`--radix` with a value of ``10``.

llvm/test/tools/llvm-size/macho-pagezero.test

@@ -6,12 +6,24 @@
 # RUN: llvm-size --exclude-pagezero %t-pagezero.o | \
 # RUN:   FileCheck %s --check-prefix=SKIP --match-full-lines
 
+# RUN: yaml2obj %s --docnum=2 -o %t-pagezero32.o
+# RUN: llvm-size %t-pagezero32.o | \
+# RUN:   FileCheck %s --check-prefix=NORMAL32 --match-full-lines
+# RUN: llvm-size --exclude-pagezero %t-pagezero32.o | \
+# RUN:   FileCheck %s --check-prefix=SKIP32 --match-full-lines
+
 # NORMAL:__TEXT	__DATA	__OBJC	others	dec	hex
 # NORMAL-NEXT:20	100	0	4096	4216	1078
 
 # SKIP:__TEXT	__DATA	__OBJC	others	dec	hex
 # SKIP-NEXT:20	100	0	0	120	78
 
+# NORMAL32:__TEXT	__DATA	__OBJC	others	dec	hex
+# NORMAL32-NEXT:20	100	0	4096	4216	1078
+
+# SKIP32:__TEXT	__DATA	__OBJC	others	dec	hex
+# SKIP32-NEXT:20	100	0	0	120	78
+
 --- !mach-o
 FileHeader:
   magic:           0xFEEDFACF
@@ -56,3 +68,47 @@ LoadCommands:
     initprot:        3
     nsects:          0
     flags:           0
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACE
+  cputype:         0x7
+  cpusubtype:      0x3
+  filetype:        0x2
+  ncmds:           3
+  sizeofcmds:      168
+  flags:           0x2000
+LoadCommands:
+  - cmd:             LC_SEGMENT
+    cmdsize:         56
+    segname:         __PAGEZERO
+    vmaddr:          0x0
+    vmsize:          4096
+    fileoff:         0
+    filesize:        0
+    maxprot:         0
+    initprot:        0
+    nsects:          0
+    flags:           0
+  - cmd:             LC_SEGMENT
+    cmdsize:         56
+    segname:         __TEXT
+    vmaddr:          0x1000
+    vmsize:          20
+    fileoff:         196
+    filesize:        20
+    maxprot:         7
+    initprot:        5
+    nsects:          0
+    flags:           0
+  - cmd:             LC_SEGMENT
+    cmdsize:         56
+    segname:         __DATA
+    vmaddr:          0x2000
+    vmsize:          100
+    fileoff:         216
+    filesize:        100
+    maxprot:         7
+    initprot:        3
+    nsects:          0
+    flags:           0