1 files changed, 90 insertions, 0 deletions
diff --git a/clang/lib/Analysis/CFGStmtMap.cpp b/clang/lib/Analysis/CFGStmtMap.cpp
new file mode 100644
index 0000000000000..d1c23e3c879b4
--- /dev/null
+++ b/clang/lib/Analysis/CFGStmtMap.cpp
@@ -0,0 +1,90 @@
+//===--- CFGStmtMap.h - Map from Stmt* to CFGBlock* -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines the CFGStmtMap class, which defines a mapping from
+//  Stmt* to CFGBlock*
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/DenseMap.h"
+#include "clang/AST/ParentMap.h"
+#include "clang/Analysis/CFG.h"
+#include "clang/Analysis/CFGStmtMap.h"
+
+using namespace clang;
+
+typedef llvm::DenseMap<const Stmt*, CFGBlock*> SMap;
+static SMap *AsMap(void *m) { return (SMap*) m; }
+
+CFGStmtMap::~CFGStmtMap() { delete AsMap(M); }
+
+CFGBlock *CFGStmtMap::getBlock(Stmt *S) {
+  SMap *SM = AsMap(M);
+  Stmt *X = S;
+
+  // If 'S' isn't in the map, walk the ParentMap to see if one of its ancestors
+  // is in the map.
+  while (X) {
+    SMap::iterator I = SM->find(X);
+    if (I != SM->end()) {
+      CFGBlock *B = I->second;
+      // Memoize this lookup.
+      if (X != S)
+        (*SM)[X] = B;
+      return B;
+    }
+
+    X = PM->getParentIgnoreParens(X);
+  }
+
+  return nullptr;
+}
+
+static void Accumulate(SMap &SM, CFGBlock *B) {
+  // First walk the block-level expressions.
+  for (CFGBlock::iterator I = B->begin(), E = B->end(); I != E; ++I) {
+    const CFGElement &CE = *I;
+    Optional<CFGStmt> CS = CE.getAs<CFGStmt>();
+    if (!CS)
+      continue;
+
+    CFGBlock *&Entry = SM[CS->getStmt()];
+    // If 'Entry' is already initialized (e.g., a terminator was already),
+    // skip.
+    if (Entry)
+      continue;
+
+    Entry = B;
+
+  }
+
+  // Look at the label of the block.
+  if (Stmt *Label = B->getLabel())
+    SM[Label] = B;
+
+  // Finally, look at the terminator.  If the terminator was already added
+  // because it is a block-level expression in another block, overwrite
+  // that mapping.
+  if (Stmt *Term = B->getTerminatorStmt())
+    SM[Term] = B;
+}
+
+CFGStmtMap *CFGStmtMap::Build(CFG *C, ParentMap *PM) {
+  if (!C || !PM)
+    return nullptr;
+
+  SMap *SM = new SMap();
+
+  // Walk all blocks, accumulating the block-level expressions, labels,
+  // and terminators.
+  for (CFG::iterator I = C->begin(), E = C->end(); I != E; ++I)
+    Accumulate(*SM, *I);
+
+  return new CFGStmtMap(PM, SM);
+}
+