[PATCH] D31199: Add "(compatible with the GNU linker)" to the -version output.

[Rui Ueyama via Phabricator via llvm-commits]

ruiu created this revision.

Previous output:

  $ ld.lld -version
  LLD 5.0.0

New output:

  $ ld.lld -versin
  LLD 5.0.0 (compatible with the GNU linker)


https://reviews.llvm.org/D31199

Files:
  lld/ELF/Driver.cpp
  lld/test/ELF/driver.test


Index: lld/test/ELF/driver.test
===================================================================
--- lld/test/ELF/driver.test
+++ lld/test/ELF/driver.test
@@ -17,7 +17,7 @@
 # HELP: USAGE:
 
 # RUN: ld.lld --version 2>&1 | FileCheck -check-prefix=VERSION %s
-# VERSION: LLD
+# VERSION: LLD {{.*}} (compatible with the GNU linker)
 
 # RUN: not ld.lld -v 2>&1 | FileCheck -check-prefix=VERSION %s
 
Index: lld/ELF/Driver.cpp
===================================================================
--- lld/ELF/Driver.cpp
+++ lld/ELF/Driver.cpp
@@ -300,11 +300,27 @@
     return;
   }
 
-  // GNU linkers disagree here. Though both -version and -v are mentioned
-  // in help to print the version information, GNU ld just normally exits,
-  // while gold can continue linking. We are compatible with ld.bfd here.
+  // Handle -v or -version.
+  //
+  // A note about "compatible with the GNU linker" message: this is a hack
+  // for scripts generated by GNU Libtool 2.4.6 (released in February 2014
+  // and still the newest version in March 2017) or earlier to recognize
+  // LLD as a GNU compatible linker. As long as an output for the -v
+  // option contains "GNU" or "BFD", they recognize us as GNU-compatible.
+  //
+  // This is somewhat ugly hack, but in reality, we had no choice other
+  // than doing this. Considering the very long release cycle of Libtool,
+  // it is not easy to improve it to recognize LLD as a GNU compatible
+  // linker in a timely manner. Even if we make it, there are still a lot
+  // of "configure" scripts that are generated by old version of
+  // Libtool. We cannot convince every software developer to migrate to
+  // the latest version and re-generate scripts. So we have this hack.
   if (Args.hasArg(OPT_version) || Args.hasArg(OPT_v))
-    message(getLLDVersion());
+    message(getLLDVersion() + " (compatible with the GNU linker)");
+
+  // ld.bfd always exits after printing out the version string.
+  // ld.gold proceeds if a given option is -v. Because gold's behavior
+  // is more permissive than ld.bfd, we chose what gold does here.
   if (Args.hasArg(OPT_version))
     return;
 


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