From 6d51d26a2479069f85a7676f664d6f998fc49a16 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Fri, 22 Jul 2011 07:50:40 +0000
Subject: [PATCH] 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135755 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/CommandLine.h |  9 +++++++++
 lib/Support/CommandLine.cpp        | 25 ++++++++++++++++++++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/include/llvm/Support/CommandLine.h b/include/llvm/Support/CommandLine.h
index d6098711a07..ba8fbee94fd 100644
--- a/include/llvm/Support/CommandLine.h
+++ b/include/llvm/Support/CommandLine.h
@@ -59,6 +59,15 @@ void ParseEnvironmentOptions(const char *progName, const char *envvar,
 ///                     CommandLine utilities to print their own version string.
 void SetVersionPrinter(void (*func)());
 
+///===---------------------------------------------------------------------===//
+/// AddExtraVersionPrinter - Add an extra printer to use in addition to the
+///                          default one. This can be called multiple times,
+///                          and each time it adds a new function to the list
+///                          which will be called after the basic LLVM version
+///                          printing is complete. Each can then add additional
+///                          information specific to the tool.
+void AddExtraVersionPrinter(void (*func)());
+
 
 // PrintOptionValues - Print option values.
 // With -print-options print the difference between option values and defaults.
diff --git a/lib/Support/CommandLine.cpp b/lib/Support/CommandLine.cpp
index 29143377628..368cef91cf5 100644
--- a/lib/Support/CommandLine.cpp
+++ b/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);
+}