Analyzer Core: Adding support for user-defined symbol dependencies. (For example, the allocated resource symbol only needs to be freed if no error has been returned by the allocator, so a checker might want to make the lifespan of the error code symbol depend on the allocated resource symbol.) Note, by default, the map that holds the dependencies will get destroyed along with the SymbolManager at the end of function exploration.

llvm-svn: 137309

1 files changed, 30 insertions, 1 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/SymbolManager.cpp b/clang/lib/StaticAnalyzer/Core/SymbolManager.cpp
index 6d90d19f9ed..b4a0d69c008 100644
--- a/clang/lib/StaticAnalyzer/Core/SymbolManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SymbolManager.cpp
@@ -248,9 +248,36 @@ bool SymbolManager::canSymbolicate(QualType T) {
   return false;
 }
 
+void SymbolManager::addSymbolDependency(const SymbolRef Primary,
+                                        const SymbolRef Dependent) {
+  SymbolDependencies[Primary].push_back(Dependent);
+}
+
+void SymbolManager::removeSymbolDependencies(const SymbolRef Primary) {
+  SymbolDependencies.erase(Primary);
+}
+
+const SymbolRefSmallVectorTy *SymbolManager::getDependentSymbols(
+                                                     const SymbolRef Primary) {
+  SymbolDependTy::const_iterator I = SymbolDependencies.find(Primary);
+  if (I == SymbolDependencies.end())
+    return 0;
+  return &I->second;
+}
+
+void SymbolReaper::markDependentsLive(SymbolRef sym) {
+  if (const SymbolRefSmallVectorTy *Deps = SymMgr.getDependentSymbols(sym)) {
+    for (SymbolRefSmallVectorTy::const_iterator I = Deps->begin(),
+                                                E = Deps->end(); I != E; ++I) {
+      markLive(*I);
+    }
+  }
+}
+
 void SymbolReaper::markLive(SymbolRef sym) {
   TheLiving.insert(sym);
   TheDead.erase(sym);
+  markDependentsLive(sym);
 }
 
 void SymbolReaper::markLive(const MemRegion *region) {
@@ -299,8 +326,10 @@ bool SymbolReaper::isLiveRegion(const MemRegion *MR) {
 }
 
 bool SymbolReaper::isLive(SymbolRef sym) {
-  if (TheLiving.count(sym))
+  if (TheLiving.count(sym)) {
+    markDependentsLive(sym);
     return true;
+  }
 
   if (const SymbolDerived *derived = dyn_cast<SymbolDerived>(sym)) {
     if (isLive(derived->getParentSymbol())) {