Add 'filtered_pred_iterator' and 'filtered_succ_iterator' to CFGBlock. This allows a client

to selectively walk successors/predecessors based on commonly used filters.  For starters, add
a filter to ignore 'default:' cases for SwitchStmts when all enum values are covered by CaseStmts.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113449 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index f0e48700d3..3dae83b564 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -1937,6 +1937,29 @@ unsigned CFG::getNumBlkExprs() {
 }
 
 //===----------------------------------------------------------------------===//
+// Filtered walking of the CFG.
+//===----------------------------------------------------------------------===//
+
+bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
+			  const CFGBlock *From, const CFGBlock *To) {
+
+  if (F.IgnoreDefaultsWithCoveredEnums) {
+    // If the 'To' has no label or is labeled but the label isn't a
+    // CaseStmt then filter this edge.
+    if (const SwitchStmt *S =
+	dyn_cast_or_null<SwitchStmt>(From->getTerminator())) {
+      if (S->isAllEnumCasesCovered()) {
+	const Stmt *L = To->getLabel();
+	if (!L || !isa<CaseStmt>(L))
+	  return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
 // Cleanup: CFG dstor.
 //===----------------------------------------------------------------------===//