2 files changed, 48 insertions, 1 deletions
diff --git a/include/clang/Analysis/Analyses/PsuedoConstantAnalysis.h b/include/clang/Analysis/Analyses/PsuedoConstantAnalysis.h
new file mode 100644
index 0000000000..080f6c1587
--- /dev/null
+++ b/include/clang/Analysis/Analyses/PsuedoConstantAnalysis.h
@@ -0,0 +1,44 @@
+//== PsuedoConstantAnalysis.h - Find Psuedo-constants in the AST -*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file tracks the usage of variables in a Decl body to see if they are
+// never written to, implying that they constant. This is useful in static
+// analysis to see if a developer might have intended a variable to be const.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_ANALYSIS_PSUEDOCONSTANTANALYSIS
+#define LLVM_CLANG_ANALYSIS_PSUEDOCONSTANTANALYSIS
+
+#include "clang/AST/Stmt.h"
+
+// The number of ValueDecls we want to keep track of by default (per-function)
+#define VALUEDECL_SET_SIZE 256
+
+namespace clang {
+
+class PsuedoConstantAnalysis {
+public:
+  PsuedoConstantAnalysis(const Stmt *DeclBody) :
+      DeclBody(DeclBody), Analyzed(false) {}
+  bool isPsuedoConstant(const ValueDecl *VD);
+
+private:
+  void RunAnalysis();
+
+  // for storing the result of analyzed ValueDecls
+  llvm::SmallPtrSet<const ValueDecl*, VALUEDECL_SET_SIZE> NonConstants;
+
+  const Stmt *DeclBody;
+  bool Analyzed;
+};
+
+}
+
+#endif
diff --git a/include/clang/Analysis/AnalysisContext.h b/include/clang/Analysis/AnalysisContext.h
index 2b595b99cb..124a08e073 100644
--- a/include/clang/Analysis/AnalysisContext.h
+++ b/include/clang/Analysis/AnalysisContext.h
@@ -30,6 +30,7 @@ class CFG;
 class CFGBlock;
 class LiveVariables;
 class ParentMap;
+class PsuedoConstantAnalysis;
 class ImplicitParamDecl;
 class LocationContextManager;
 class StackFrameContext;
@@ -49,6 +50,7 @@ class AnalysisContext {
   bool builtCFG, builtCompleteCFG;
   LiveVariables *liveness;
   ParentMap *PM;
+  PsuedoConstantAnalysis *PCA;
   llvm::DenseMap<const BlockDecl*,void*> *ReferencedBlockVars;
   llvm::BumpPtrAllocator A;
   bool UseUnoptimizedCFG;  
@@ -59,7 +61,7 @@ public:
                   bool addehedges = false)
     : D(d), TU(tu), cfg(0), completeCFG(0),
       builtCFG(false), builtCompleteCFG(false),
-      liveness(0), PM(0),
+      liveness(0), PM(0), PCA(0),
       ReferencedBlockVars(0), UseUnoptimizedCFG(useUnoptimizedCFG),
       AddEHEdges(addehedges) {}
 
@@ -85,6 +87,7 @@ public:
   CFG *getUnoptimizedCFG();
 
   ParentMap &getParentMap();
+  PsuedoConstantAnalysis *getPsuedoConstantAnalysis();
   LiveVariables *getLiveVariables();
 
   typedef const VarDecl * const * referenced_decls_iterator;