[PATCH] D147663: [lld-macho] Add new -reproducible flag

[Keith Smiley via Phabricator via llvm-commits]

keith created this revision.
Herald added projects: lld-macho, All.
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As of Xcode 14.3 it passes -reproducible by default to ld64. It seems
this flag was added in ld64 with Xcode 14.0, but it is not documented.
Through my testing the only thing I have seen it do is the same as
ZERO_AR_DATE, but it's possible it does more, or will do more in the
future. Since we already default to this option, this is more about
handling the command line flag to maintain Xcode compatibility than
anything else.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147663

Files:
  lld/MachO/Driver.cpp
  lld/MachO/Options.td
  lld/test/MachO/stabs.s


Index: lld/test/MachO/stabs.s
===================================================================
--- lld/test/MachO/stabs.s
+++ lld/test/MachO/stabs.s
@@ -42,6 +42,11 @@
 # RUN: (llvm-objdump --section-headers %t/test; dsymutil -s %t/test) | \
 # RUN:   FileCheck %s -DDIR=%t -DFOO_PATH=%t/foo.a\(foo.o\) \
 # RUN:       -D#TEST_TIME=0 -D#FOO_TIME=0
+# RUN: env ZERO_AR_DATE=0 %lld -lSystem -reproducible %t/test.o %t/foo.o \
+# RUN:     %t/no-debug.o -o %t/test
+# RUN: (llvm-objdump --section-headers %t/test; dsymutil -s %t/test) | \
+# RUN:   FileCheck %s -DDIR=%t -DFOO_PATH=%t/foo.o \
+# RUN:       -D#TEST_TIME=0 -D#FOO_TIME=0
 
 ## Check that we emit absolute paths to the object files in our OSO entries
 ## even if our inputs are relative paths.
Index: lld/MachO/Options.td
===================================================================
--- lld/MachO/Options.td
+++ lld/MachO/Options.td
@@ -670,6 +670,9 @@
 def no_adhoc_codesign : Flag<["-"], "no_adhoc_codesign">,
     HelpText<"Do not write an ad-hoc code signature to the output file (default for x86_64 binaries)">,
     Group<grp_rare>;
+def reproducible : Flag<["-"], "reproducible">,
+    HelpText<"Make the output reproducible by removing timestamps and other non-deterministic data, this is the default">,
+    Group<grp_rare>;
 def version_details : Flag<["-"], "version_details">,
     HelpText<"Print the linker version in JSON form">,
     Flags<[HelpHidden]>,
Index: lld/MachO/Driver.cpp
===================================================================
--- lld/MachO/Driver.cpp
+++ lld/MachO/Driver.cpp
@@ -1644,9 +1644,10 @@
         std::make_pair(arg->getValue(0), arg->getValue(1)));
   }
 
-  // FIXME: Add a commandline flag for this too.
   if (const char *zero = getenv("ZERO_AR_DATE"))
     config->zeroModTime = strcmp(zero, "0") != 0;
+  if (args.getLastArg(OPT_reproducible))
+    config->zeroModTime = true;
 
   std::array<PlatformType, 3> encryptablePlatforms{
       PLATFORM_IOS, PLATFORM_WATCHOS, PLATFORM_TVOS};


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