[llvm-size] Add -z option for Mach-O to exclude __PAGEZERO size.

Fixes #86644

Author: rjmansfield

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

@@ -0,0 +1,60 @@
+# Test the -z option to skip __PAGEZERO segment in Mach-O files
+
+# RUN: yaml2obj %s --docnum=1 -o %t-pagezero.o
+# RUN: llvm-size %t-pagezero.o | \
+# RUN:   FileCheck %s --check-prefix=NORMAL --match-full-lines \
+# RUN:                --strict-whitespace --implicit-check-not={{.}}
+# RUN: llvm-size -z %t-pagezero.o | \
+# RUN:   FileCheck %s --check-prefix=SKIP --match-full-lines \
+# RUN:                --strict-whitespace --implicit-check-not={{.}}
+
+# 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	
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x100000C
+  cpusubtype:      0x0
+  filetype:        0x2
+  ncmds:           3
+  sizeofcmds:      216
+  flags:           0x2000
+  reserved:        0x0
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         72
+    segname:         __PAGEZERO
+    vmaddr:          0x0
+    vmsize:          4096
+    fileoff:         0
+    filesize:        0
+    maxprot:         0
+    initprot:        0
+    nsects:          0
+    flags:           0
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         72
+    segname:         __TEXT
+    vmaddr:          0x100000000
+    vmsize:          20
+    fileoff:         248
+    filesize:        20
+    maxprot:         7
+    initprot:        5
+    nsects:          0
+    flags:           0
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         72
+    segname:         __DATA
+    vmaddr:          0x100001000
+    vmsize:          100
+    fileoff:         268
+    filesize:        100
+    maxprot:         7
+    initprot:        3
+    nsects:          0
+    flags:           0

llvm/tools/llvm-size/Opts.td

@@ -21,6 +21,8 @@ def grp_mach_o : OptionGroup<"kind">, HelpText<"OPTIONS (Mach-O specific)">;
 def arch_EQ : Joined<["--"], "arch=">, HelpText<"architecture(s) from a Mach-O file to dump">, Group<grp_mach_o>;
 def : Separate<["--", "-"], "arch">, Alias<arch_EQ>;
 def l : F<"l", "When format is darwin, use long format to include addresses and offsets">, Group<grp_mach_o>;
+def z : F<"z", "Do not include __PAGEZERO segment in totals">,
+        Group<grp_mach_o>;
 
 def : F<"A", "Alias for --format">, Alias<format_EQ>, AliasArgs<["sysv"]>;
 def : F<"B", "Alias for --format">, Alias<format_EQ>, AliasArgs<["berkeley"]>;

llvm/tools/llvm-size/llvm-size.cpp

@@ -79,6 +79,7 @@ static bool DarwinLongFormat;
 static RadixTy Radix = RadixTy::decimal;
 static bool TotalSizes;
 static bool HasMachOFiles = false;
+static bool SkipPageZero = false;
 
 static std::vector<std::string> InputFilenames;
 
@@ -307,7 +308,9 @@ static void printDarwinSegmentSizes(MachOObjectFile *MachO) {
         }
       } else {
         StringRef SegmentName = StringRef(Seg.segname);
-        if (SegmentName == "__TEXT")
+        if (SkipPageZero && SegmentName == "__PAGEZERO")
+          ; // Skip __PAGEZERO segment
+        else if (SegmentName == "__TEXT")
           total_text += Seg.vmsize;
         else if (SegmentName == "__DATA")
           total_data += Seg.vmsize;
@@ -333,7 +336,9 @@ static void printDarwinSegmentSizes(MachOObjectFile *MachO) {
         }
       } else {
         StringRef SegmentName = StringRef(Seg.segname);
-        if (SegmentName == "__TEXT")
+        if (SkipPageZero && SegmentName == "__PAGEZERO")
+          ; // Skip __PAGEZERO segment
+        else if (SegmentName == "__TEXT")
           total_text += Seg.vmsize;
         else if (SegmentName == "__DATA")
           total_data += Seg.vmsize;
@@ -914,6 +919,7 @@ int llvm_size_main(int argc, char **argv, const llvm::ToolContext &) {
 
   ELFCommons = Args.hasArg(OPT_common);
   DarwinLongFormat = Args.hasArg(OPT_l);
+  SkipPageZero = Args.hasArg(OPT_z);
   TotalSizes = Args.hasArg(OPT_totals);
   StringRef V = Args.getLastArgValue(OPT_format_EQ, "berkeley");
   if (V == "berkeley")