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authorTimotej Kapus <tk1713@ic.ac.uk>2019-11-07 14:27:07 +0000
committerCristian Cadar <c.cadar@imperial.ac.uk>2019-12-12 17:50:24 +0000
commitd8deadd787d0f857d701b73aeaa3e0753efd9405 (patch)
tree4c28ae2980194460f6694b807fc8ede72aff57f9 /lib
parentebd3eb0ec11b053ddf5eee44c1217436948279d9 (diff)
downloadklee-d8deadd787d0f857d701b73aeaa3e0753efd9405.tar.gz
[optimize-array] Fix update list read order
ArrayExprOptimizer read the UpdateList in the wrong order, which
meant that it used least recent update instead of the most recent one.
This patch fixes this as well as adds a test to illustrate the issue.
Diffstat (limited to 'lib')
-rw-r--r--lib/Expr/ArrayExprOptimizer.cpp22
1 files changed, 20 insertions, 2 deletions
diff --git a/lib/Expr/ArrayExprOptimizer.cpp b/lib/Expr/ArrayExprOptimizer.cpp
index 1a48adfe..e43530ec 100644
--- a/lib/Expr/ArrayExprOptimizer.cpp
+++ b/lib/Expr/ArrayExprOptimizer.cpp
@@ -280,8 +280,17 @@ ref<Expr> ExprOptimizer::getSelectOptExpr(
       // assume that the UpdateNodes contain ConstantExpr indexes and values
       assert(read->updates.root->isConstantArray() &&
              "Expected concrete array, found symbolic array");
+
+      // We need to read updates from lest recent to most recent, therefore
+      // reverse the list
+      std::vector<const UpdateNode *> us;
+      us.reserve(read->updates.getSize());
+      for (const UpdateNode *un = read->updates.head; un; un = un->next)
+        us.push_back(un);
+
       auto arrayConstValues = read->updates.root->constantValues;
-      for (const UpdateNode *un = read->updates.head; un; un = un->next) {
+      for (auto it = us.rbegin(); it != us.rend(); it++) {
+        const UpdateNode *un = *it;
         auto ce = dyn_cast<ConstantExpr>(un->index);
         assert(ce && "Not a constant expression");
         uint64_t index = ce->getAPValue().getZExtValue();
@@ -356,7 +365,16 @@ ref<Expr> ExprOptimizer::getSelectOptExpr(
           arrayConstValues.push_back(ConstantExpr::create(0, Expr::Int8));
         }
       }
-      for (const UpdateNode *un = read->updates.head; un; un = un->next) {
+
+      // We need to read updates from lest recent to most recent, therefore
+      // reverse the list
+      std::vector<const UpdateNode *> us;
+      us.reserve(read->updates.getSize());
+      for (const UpdateNode *un = read->updates.head; un; un = un->next)
+        us.push_back(un);
+
+      for (auto it = us.rbegin(); it != us.rend(); it++) {
+        const UpdateNode *un = *it;
         auto ce = dyn_cast<ConstantExpr>(un->index);
         assert(ce && "Not a constant expression");
         uint64_t index = ce->getAPValue().getLimitedValue();