Merge pull request swiftlang#9699 from swiftlang/cherrypick-swift/release/6.1-f7261e9bbe33

[🍒 swift/release/6.1] [dsymutil] Emit a warning instead of an error when using fat64 header (llvm#118898)

Author: JDevlieghere

llvm/tools/dsymutil/dsymutil.cpp

@@ -839,15 +839,15 @@ int dsymutil_main(int argc, char **argv, const llvm::ToolContext &) {
       return EXIT_FAILURE;
 
     if (NeedsTempFiles) {
-      const bool Fat64 = Options.LinkOpts.Fat64;
+      bool Fat64 = Options.LinkOpts.Fat64;
       if (!Fat64) {
         // Universal Mach-O files can't have an archicture slice that starts
         // beyond the 4GB boundary. "lipo" can create a 64 bit universal
-        // header, but not all tools can parse these files so we want to return
-        // an error if the file can't be encoded as a file with a 32 bit
+        // header, but older tools may not support these files so we want to
+        // emit a warning if the file can't be encoded as a file with a 32 bit
         // universal header. To detect this, we check the size of each
         // architecture's skinny Mach-O file and add up the offsets. If they
-        // exceed 4GB, then we return an error.
+        // exceed 4GB, we emit a warning.
 
         // First we compute the right offset where the first architecture will
         // fit followin the 32 bit universal header. The 32 bit universal header
@@ -866,13 +866,15 @@ int dsymutil_main(int argc, char **argv, const llvm::ToolContext &) {
           if (!stat)
             break;
           if (FileOffset > UINT32_MAX) {
-            WithColor::error()
-                << formatv("the universal binary has a slice with a starting "
-                           "offset ({0:x}) that exceeds 4GB and will produce "
-                           "an invalid Mach-O file. Use the -fat64 flag to "
-                           "generate a universal binary with a 64-bit header "
-                           "but note that not all tools support this format.",
-                           FileOffset);
+            Fat64 = true;
+            WithColor::warning() << formatv(
+                "the universal binary has a slice with a starting offset "
+                "({0:x}) that exceeds 4GB. To avoid producing an invalid "
+                "Mach-O file, a universal binary with a 64-bit header will be "
+                "generated, which may not be supported by older tools. Use the "
+                "-fat64 flag to force a 64-bit header and silence this "
+                "warning.",
+                FileOffset);
             return EXIT_FAILURE;
           }
           FileOffset += stat->getSize();