[PATCH] D65453: Improve the accuracy of the Clang call graph analysis

[Joshua Cranmer via Phabricator via cfe-commits]

jcranmer-intel created this revision.
jcranmer-intel added a reviewer: dcoughlin.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

This patch improves Clang call graph analysis by adding in expressions that are not found in regular function bodies, such as default arguments or C++ member initializers.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D65453

Files:
  clang/lib/Analysis/CallGraph.cpp
  clang/test/Analysis/cxx-callgraph.cpp


Index: clang/test/Analysis/cxx-callgraph.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/cxx-callgraph.cpp
@@ -0,0 +1,29 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.DumpCallGraph %s 2>&1 | FileCheck %s
+
+static int aaa() {
+  return 0;
+}
+
+static int bbb(int param=aaa()) {
+  return 1;
+}
+
+int ddd();
+
+struct c {
+  c(int param=2) : val(bbb(param)) {}
+  int val;
+  int val2 = ddd();
+};
+
+int ddd() {
+  c c;
+  return bbb();
+}
+
+// CHECK:--- Call graph Dump ---
+// CHECK-NEXT: {{Function: < root > calls: aaa bbb c::c ddd}}
+// CHECK-NEXT: {{Function: c::c calls: bbb ddd $}}
+// CHECK-NEXT: {{Function: ddd calls: c::c bbb aaa $}}
+// CHECK-NEXT: {{Function: bbb calls: $}}
+// CHECK-NEXT: {{Function: aaa calls: $}}
Index: clang/lib/Analysis/CallGraph.cpp
===================================================================
--- clang/lib/Analysis/CallGraph.cpp
+++ clang/lib/Analysis/CallGraph.cpp
@@ -103,6 +103,16 @@
     VisitChildren(E);
   }
 
+  // Include the evaluation of the default argument.
+  void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *E) {
+    Visit(E->getExpr());
+  }
+
+  // Include the evaluation of the default initializers in a class.
+  void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *E) {
+    Visit(E->getExpr());
+  }
+
   // Adds may-call edges for the ObjC message sends.
   void VisitObjCMessageExpr(ObjCMessageExpr *ME) {
     if (ObjCInterfaceDecl *IDecl = ME->getReceiverInterface()) {
@@ -167,13 +177,20 @@
 void CallGraph::addNodeForDecl(Decl* D, bool IsGlobal) {
   assert(D);
 
-  // Allocate a new node, mark it as root, and process it's calls.
+  // Allocate a new node, mark it as root, and process its calls.
   CallGraphNode *Node = getOrInsertNode(D);
 
   // Process all the calls by this function as well.
   CGBuilder builder(this, Node);
   if (Stmt *Body = D->getBody())
     builder.Visit(Body);
+
+  // Include C++ constructor member initializers.
+  if (auto constructor = dyn_cast<CXXConstructorDecl>(D)) {
+    for (CXXCtorInitializer *init : constructor->inits()) {
+      builder.Visit(init->getInit());
+    }
+  }
 }
 
 CallGraphNode *CallGraph::getNode(const Decl *F) const {


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