[lld-macho] Downgrade version mismatch to warning

[int3]

Summary

It's a warning in ld64. While having LLD be stricter would be nice, it
makes it harder for it to be a drop-in replacement into existing builds.

[thakis]

:/

Looks like this lacks test coverage if it needs no test update to go along with it?

[int3]

We did have a test actually. I just I forgot we had %no_fatal_warnings_lld, which makes it not-too-ugly to test for warnings instead of errors... updating that test now

[int3]

update test

lld/MachO/InputFiles.cpp

interleave(
         },
         "/");
     error(toString(input) + " has platform " + platformNames +
           Twine(", which is different from target platform ") +
           getPlatformName(config->platform()));
     return false;
   }
 
-  if (it->minimum <= config->platformInfo.minimum)
-    return true;
-
-  error(toString(input) + " has version " + it->minimum.getAsString() +
+  if (it->minimum > config->platformInfo.minimum)
+    warn(toString(input) + " has version " + it->minimum.getAsString() +
          ", which is newer than target minimum of " +
          config->platformInfo.minimum.getAsString());
-  return false;
+
+  return true;
 }
 
 // Open a given file path and return it as a memory-mapped file.
 Optional<MemoryBufferRef> macho::readFile(StringRef path) {
   ErrorOr<std::unique_ptr<MemoryBuffer>> mbOrErr = MemoryBuffer::getFile(path);
   if (std::error_code ec = mbOrErr.getError()) {
     error("cannot open " + path + ": " + ec.message());
     return None;

lld/test/MachO/invalid/incompatible-arch.s

 # REQUIRES: aarch64, x86
 
 # RUN: rm -rf %t && mkdir -p %t
 
 # RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin %s -o %t/test.o
 # RUN: not %lld -arch x86_64 -lSystem %t/test.o -o /dev/null 2>&1 | FileCheck %s -DFILE=%t/test.o
 # CHECK: error: {{.*}}[[FILE]] has architecture arm64 which is incompatible with target architecture x86_64
 
 # RUN: %lld -dylib -arch arm64 -platform_version macOS 10.14 10.15 -o %t/out.dylib %t/test.o
 
 # RUN: not %lld -dylib -arch arm64 -platform_version iOS 9.0 11.0 %t/out.dylib \
 # RUN:  -o /dev/null 2>&1 | FileCheck %s --check-prefix=DYLIB-PLAT
 # DYLIB-PLAT: {{.*}}out.dylib has platform macOS, which is different from target platform iOS
 
 # RUN: %lld -lSystem -dylib -arch arm64 -platform_version macOS 10.14.0 10.15.0 %t/out.dylib -o /dev/null
 
-# RUN: not %lld -lSystem -dylib -arch arm64 -platform_version macOS 10.13.0 10.15.0 %t/out.dylib \
+# RUN: %no_fatal_warnings_lld -lSystem -dylib -arch arm64 -platform_version macOS 10.13.0 10.15.0 %t/out.dylib \
 # RUN:  -o /dev/null 2>&1 | FileCheck %s --check-prefix=DYLIB-VERSION
-# DYLIB-VERSION: {{.*}}out.dylib has version 10.14.0, which is newer than target minimum of 10.13.0
+# DYLIB-VERSION: warning: {{.*}}out.dylib has version 10.14.0, which is newer than target minimum of 10.13.0
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos10.15.0 %s -o %t/test_x86.o
 
 # RUN: not %lld %t/test_x86.o -lSystem -arch x86_64 -platform_version iOS 10.0 15.0 \
 # RUN:  -o /dev/null 2>&1 | FileCheck %s --check-prefix=OBJ-PLAT
 # OBJ-PLAT: {{.*}}test_x86.o has platform macOS, which is different from target platform iOS
 
 # RUN: %lld %t/test_x86.o -lSystem -arch x86_64 -platform_version macOS 10.15.0 10.15.0 -o /dev/null
 
-# RUN: not %lld %t/test_x86.o -lSystem -arch x86_64 -platform_version macOS 10.14.0 10.15.0 \
+# RUN: %no_fatal_warnings_lld %t/test_x86.o -lSystem -arch x86_64 -platform_version macOS 10.14.0 10.15.0 \
 # RUN:  -o /dev/null 2>&1 | FileCheck %s --check-prefix=OBJ-VERSION
-# OBJ-VERSION: {{.*}}test_x86.o has version 10.15.0, which is newer than target minimum of 10.14.0
+# OBJ-VERSION: warning: {{.*}}test_x86.o has version 10.15.0, which is newer than target minimum of 10.14.0
 
 ## Test that simulators platforms are compat with their simulatees.   
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-ios14.0 %s -o %t/test_x86_ios.o
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-ios14.0-simulator %s -o %t/test_x86_ios_sim.o
 
 # RUN: %lld -dylib -platform_version ios-simulator 14.0.0 14.0.0 %t/test_x86_ios.o -o /dev/null
 # RUN: %lld -dylib -platform_version ios 14.0.0 14.0.0 %t/test_x86_ios_sim.o -o /dev/null