When building a module, use the macro definitions on the command line

as part of the hash rather than ignoring them. This means we'll end up
building more module variants (overall), but it allows configuration
macros such as NDEBUG to work so long as they're specified via command
line. More to come in this space.

llvm-svn: 142187

clang/lib/Frontend/CompilerInvocation.cpp

@@ -2026,6 +2026,23 @@ std::string CompilerInvocation::getModuleHash() const {
   Signature.add(getPreprocessorOpts().UsePredefines, 1);
   Signature.add(getPreprocessorOpts().DetailedRecord, 1);
   
+  // Hash the preprocessor defines.
+  // FIXME: This is terrible. Use an MD5 sum of the preprocessor defines.
+  std::vector<StringRef> MacroDefs;
+  for (std::vector<std::pair<std::string, bool/*isUndef*/> >::const_iterator 
+            I = getPreprocessorOpts().Macros.begin(),
+         IEnd = getPreprocessorOpts().Macros.end();
+       I != IEnd; ++I) {
+    if (!I->second)
+      MacroDefs.push_back(I->first);
+  }
+  llvm::array_pod_sort(MacroDefs.begin(), MacroDefs.end());
+       
+  unsigned PPHashResult = 0;
+  for (unsigned I = 0, N = MacroDefs.size(); I != N; ++I)
+    PPHashResult = llvm::HashString(MacroDefs[I], PPHashResult);
+  Signature.add(PPHashResult, 32);
+  
   // We've generated the signature. Treat it as one large APInt that we'll
   // encode in base-36 and return.
   Signature.flush();