add a couple of helpers to the Triple class for decoding

the darwin version string.  This should help consolidate
the variety of weird functions we have scattered around the
codebase that do stuff like this.

llvm-svn: 78792

llvm/include/llvm/ADT/Triple.h

@@ -158,6 +158,21 @@ public:
   /// if the environment component is present).
   StringRef getOSAndEnvironmentName() const;
 
+  
+  /// getDarwinNumber - Parse the 'darwin number' out of the specific target
+  /// triple.  For example, if we have darwin8.5 return 8,5,0.  If any entry is
+  /// not defined, return 0's.  This requires that the triple have an OSType of
+  /// darwin before it is called.
+  void getDarwinNumber(unsigned &Maj, unsigned &Min, unsigned &Revision) const;
+  
+  /// getDarwinMajorNumber - Return just the major version number, this is
+  /// specialized because it is a common query.
+  unsigned getDarwinMajorNumber() const {
+    unsigned Maj, Min, Rev;
+    getDarwinNumber(Maj, Min, Rev);
+    return Maj;
+  }
+  
   /// @}
   /// @name Mutators
   /// @{

llvm/lib/Support/Triple.cpp

@@ -209,6 +209,71 @@ StringRef Triple::getOSAndEnvironmentName() const {
   return Tmp.split('-').second;                      // Strip second component
 }
 
+static unsigned EatNumber(StringRef &Str) {
+  assert(!Str.empty() && Str[0] >= '0' && Str[0] <= '9' && "Not a number");
+  unsigned Result = Str[0]-'0';
+  
+  // Eat the digit.
+  Str = Str.substr(1);
+  
+  // Handle "darwin11".
+  if (Result == 1 && !Str.empty() && Str[0] >= '0' && Str[0] <= '9') {
+    Result = Result*10 + (Str[0] - '0');
+    // Eat the digit.
+    Str = Str.substr(1);
+  }
+  
+  return Result;
+}
+
+/// getDarwinNumber - Parse the 'darwin number' out of the specific target
+/// triple.  For example, if we have darwin8.5 return 8,5,0.  If any entry is
+/// not defined, return 0's.  This requires that the triple have an OSType of
+/// darwin before it is called.
+void Triple::getDarwinNumber(unsigned &Maj, unsigned &Min,
+                             unsigned &Revision) const {
+  assert(getOS() == Darwin && "Not a darwin target triple!");
+  StringRef OSName = getOSName();
+  assert(OSName.startswith("darwin") && "Unknown darwin target triple!");
+  
+  // Strip off "darwin".
+  OSName = OSName.substr(6);
+  
+  Maj = Min = Revision = 0;
+
+  if (OSName.empty() || OSName[0] < '0' || OSName[0] > '9')
+    return;
+
+  // The major version is the first digit.
+  Maj = EatNumber(OSName);
+  if (OSName.empty()) return;
+  
+  // Handle minor version: 10.4.9 -> darwin8.9.
+  if (OSName[0] != '.')
+    return;
+  
+  // Eat the '.'.
+  OSName = OSName.substr(1);
+
+  if (OSName.empty() || OSName[0] < '0' || OSName[0] > '9')
+    return;
+  
+  Min = EatNumber(OSName);
+  if (OSName.empty()) return;
+
+  // Handle revision darwin8.9.1
+  if (OSName[0] != '.')
+    return;
+  
+  // Eat the '.'.
+  OSName = OSName.substr(1);
+  
+  if (OSName.empty() || OSName[0] < '0' || OSName[0] > '9')
+    return;
+
+  Revision = EatNumber(OSName);
+}
+
 void Triple::setTriple(const Twine &Str) {
   Data = Str.str();
   Arch = InvalidArch;