[lld-macho] Fix min version check

[int3]

Summary

We had got it backwards... the minimum version of the target
should be higher than the min version of the object files, presumably
since new platforms are backwards-compatible with older formats.

Fixes PR50078.

[thakis]

:)

Maybe mention the PR this fixes in the commit msg

[int3]

I goofed and forgot to run the rest of the test suite before landing. Turns out we had silent version mismatches everywhere. I've temporarily made our tests target the older version in rG8c17a875150f8e736e8f9061ddf084397f45f4c5, but will follow up with a diff to make everything just target a modern version instead.

lld/MachO/InputFiles.cpp

template <class LP> static bool checkCompatibility(const InputFile *input) {
   // TODO: Correctly detect simulator platforms or relax this check.
   if (config->platform() != platformInfo->target.Platform) {
     error(toString(input) + " has platform " +
           getPlatformName(platformInfo->target.Platform) +
           Twine(", which is different from target platform ") +
           getPlatformName(config->platform()));
     return false;
   }
-  if (platformInfo->minimum >= config->platformInfo.minimum)
+  if (platformInfo->minimum <= config->platformInfo.minimum)
     return true;
   error(toString(input) + " has version " +
         platformInfo->minimum.getAsString() +
-        ", which is incompatible with target version of " +
+        ", which is newer than target minimum of " +
         config->platformInfo.minimum.getAsString());
   return false;
 }
 
 // Open a given file path and return it as a memory-mapped file.
 Optional<MemoryBufferRef> macho::readFile(StringRef path) {
   // Open a file.
   ErrorOr<std::unique_ptr<MemoryBuffer>> mbOrErr = MemoryBuffer::getFile(path);

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 9.0 11.0 -o %t/out.dylib %t/test.o
+# 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: 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: not %lld -dylib -arch arm64 -platform_version macOS 14.0 15.0  %t/out.dylib  \
+# 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:  -o /dev/null 2>&1 | FileCheck %s --check-prefix=DYLIB-VERSION
-# DYLIB-VERSION: {{.*}}out.dylib has version 9.0.0, which is incompatible with target version of 14.0
+# DYLIB-VERSION: {{.*}}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: not %lld %t/test_x86.o -lSystem -arch x86_64 -platform_version macOS 14.0 15.0 \
+# 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:  -o /dev/null 2>&1 | FileCheck %s --check-prefix=OBJ-VERSION
-# OBJ-VERSION: {{.*}}test_x86.o has version 10.15.0, which is incompatible with target version of 14.0
+# OBJ-VERSION: {{.*}}test_x86.o has version 10.15.0, which is newer than target minimum of 10.14.0
 
 .globl _main
 _main:
   ret