[PATCH] D16044: getVariableName() for MemRegion

[Alexander Droste via cfe-commits]

Alexander_Droste updated this revision to Diff 48953.
Alexander_Droste added a comment.

- remove string idx variable -> remove string copy assignments
- use Twine to reduce temporary string objects, built during concatenation

Is `ArrayIndices = llvm::Twine(ArrayIndices + "]" + intValAsString.str() + "[").str();`
preferable to: `ArrayIndices += llvm::Twine("]" + intValAsString.str() + "[").str();`
with respect to efficiency? If not, I would prefer the second version, as it is a bit more concise.


http://reviews.llvm.org/D16044

Files:
  include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
  lib/StaticAnalyzer/Core/MemRegion.cpp

Index: include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
@@ -150,6 +150,14 @@
   template<typename RegionTy> const RegionTy* getAs() const;
 
   virtual bool isBoundable() const { return false; }
+
+  /// Get variable name for memory region. The name is obtained from
+  /// the variable/field declaration retrieved from the memory region.
+  /// Regions that point to an element of an array are returned as: "arr[0]".
+  /// Regions that point to a struct are returned as: "st.var".
+  ///
+  /// \returns variable name for memory region
+  std::string getVariableName() const;
 };
 
 /// MemSpaceRegion - A memory region that represents a "memory space";
Index: lib/StaticAnalyzer/Core/MemRegion.cpp
===================================================================
--- lib/StaticAnalyzer/Core/MemRegion.cpp
+++ lib/StaticAnalyzer/Core/MemRegion.cpp
@@ -632,6 +632,49 @@
   superRegion->printPrettyAsExpr(os);
 }
 
+std::string MemRegion::getVariableName() const {
+  std::string VariableName;
+  std::string ArrayIndices;
+  const MemRegion *R = this;
+  SmallString<50> buf;
+  llvm::raw_svector_ostream os(buf);
+
+  // Obtain array indices to add them to the variable name.
+  const ElementRegion *ER = nullptr;
+  while ((ER = R->getAs<ElementRegion>())) {
+    // Index is a ConcreteInt.
+    if (auto CI = ER->getIndex().getAs<nonloc::ConcreteInt>()) {
+      llvm::SmallString<2> intValAsString;
+      CI->getValue().toString(intValAsString);
+      ArrayIndices =
+          llvm::Twine(ArrayIndices + "]" + intValAsString.str() + "[").str();
+    }
+    // If not a ConcreteInt, try to obtain the variable
+    // name by calling 'getVariableName()' recursively.
+    else {
+      std::string idx = ER->getVariableName();
+      if (!idx.empty()) {
+        // Substring to exclude single quotes surrounding the index var name.
+        ArrayIndices = llvm::Twine(ArrayIndices + "]" +
+                                   idx.substr(1, idx.size() - 2) + "[")
+                           .str();
+      }
+    }
+    R = ER->getSuperRegion();
+  }
+  std::reverse(ArrayIndices.begin(), ArrayIndices.end());
+
+  // Get variable name.
+  if (R && R->canPrintPretty()) {
+    R->printPretty(os);
+    VariableName = os.str();
+    // Combine variable name with indices.
+    VariableName.insert(VariableName.size() - 1, ArrayIndices);
+  }
+
+  return VariableName;
+}
+
 //===----------------------------------------------------------------------===//
 // MemRegionManager methods.
 //===----------------------------------------------------------------------===//


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