Add an extension point to the CommandLine library where clients can

register extra version information to be printed. This is designed to
allow those tools which link in various targets to also print those
registered targets under --version.

Currently this printing logic is embedded into the Support library
directly; a huge layering violation. This is the first step to hoisting
it out into the tools without adding lots of duplicated code.

llvm-svn: 135755

1 files changed, 22 insertions, 3 deletions

diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index 29143377628..368cef91cf5 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -1330,6 +1330,8 @@ void cl::PrintOptionValues() {
 
 static void (*OverrideVersionPrinter)() = 0;
 
+static std::vector<void (*)()>* ExtraVersionPrinters = 0;
+
 static int TargetArraySortFn(const void *LHS, const void *RHS) {
   typedef std::pair<const char *, const Target*> pair_ty;
   return strcmp(((const pair_ty*)LHS)->first, ((const pair_ty*)RHS)->first);
@@ -1387,11 +1389,21 @@ public:
   void operator=(bool OptionWasSpecified) {
     if (!OptionWasSpecified) return;
 
-    if (OverrideVersionPrinter == 0) {
-      print();
+    if (OverrideVersionPrinter != 0) {
+      (*OverrideVersionPrinter)();
       exit(1);
     }
-    (*OverrideVersionPrinter)();
+    print();
+
+    // Iterate over any registered extra printers and call them to add further
+    // information.
+    if (ExtraVersionPrinters != 0) {
+      for (std::vector<void (*)()>::iterator I = ExtraVersionPrinters->begin(),
+                                             E = ExtraVersionPrinters->end();
+           I != E; ++I)
+        (*I)();
+    }
+
     exit(1);
   }
 };
@@ -1424,3 +1436,10 @@ void cl::PrintVersionMessage() {
 void cl::SetVersionPrinter(void (*func)()) {
   OverrideVersionPrinter = func;
 }
+
+void cl::AddExtraVersionPrinter(void (*func)()) {
+  if (ExtraVersionPrinters == 0)
+    ExtraVersionPrinters = new std::vector<void (*)()>;
+
+  ExtraVersionPrinters->push_back(func);
+}