[cfe-commits] r171219 - /cfe/trunk/lib/Driver/ToolChains.cpp

[Chandler Carruth]

Author: chandlerc
Date: Sat Dec 29 06:01:08 2012
New Revision: 171219

URL: http://llvm.org/viewvc/llvm-project?rev=171219&view=rev
Log:
Try to re-structure the GCCVersion comparison routine to make it easier
to read and tell that it is a SWO -- we now descend through the
components and return a result at the first inequal component.

Also comment it a bit better and make it a total ordering by sorting on
the text of the suffix if necessary.

None of this should really be a visible change.

Modified:
    cfe/trunk/lib/Driver/ToolChains.cpp

Modified: cfe/trunk/lib/Driver/ToolChains.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains.cpp?rev=171219&r1=171218&r2=171219&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/ToolChains.cpp (original)
+++ cfe/trunk/lib/Driver/ToolChains.cpp Sat Dec 29 06:01:08 2012
@@ -966,20 +966,33 @@
 
 /// \brief Less-than for GCCVersion, implementing a Strict Weak Ordering.
 bool Generic_GCC::GCCVersion::operator<(const GCCVersion &RHS) const {
-  if (Major < RHS.Major) return true; if (Major > RHS.Major) return false;
-  if (Minor < RHS.Minor) return true; if (Minor > RHS.Minor) return false;
+  if (Major != RHS.Major)
+    return Major < RHS.Major;
+  if (Minor != RHS.Minor)
+    return Minor < RHS.Minor;
+  if (Patch != RHS.Patch) {
+    // Note that versions without a specified patch sort higher than those with
+    // a patch.
+    if (RHS.Patch == -1)
+      return true;
+    if (Patch == -1)
+      return false;
+
+    // Otherwise just sort on the patch itself.
+    return Patch < RHS.Patch;
+  }
+  if (PatchSuffix != RHS.PatchSuffix) {
+    // Sort empty suffixes higher.
+    if (RHS.PatchSuffix.empty())
+      return true;
+    if (PatchSuffix.empty())
+      return true;
 
-  // Note that we rank versions with *no* patch specified is better than ones
-  // hard-coding a patch version. Thus if only the RHS or LHS has no patch,
-  // it wins.
-  if (RHS.Patch == -1 && Patch != -1) return true;
-  if (RHS.Patch != -1 && Patch == -1) return false;
-  if (Patch < RHS.Patch) return true; if (Patch > RHS.Patch) return false;
-  if (PatchSuffix == RHS.PatchSuffix) return false;
-
-  // Finally, between completely tied version numbers, the version with the
-  // suffix loses as we prefer full releases.
-  if (RHS.PatchSuffix.empty()) return true;
+    // Provide a lexicographic sort to make this a total ordering.
+    return PatchSuffix < RHS.PatchSuffix;
+  }
+
+  // The versions are equal.
   return false;
 }