[PATCH] D152813: [clang][dataflow] Create `Value`s for integer literals.

[Martin Böhme via Phabricator via cfe-commits]

mboehme created this revision.
Herald added subscribers: martong, xazax.hun.
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This patch includes a test that fails without the fix.

I discovered that we weren't creating `Value`s for integer literals when, in a
different patch, I tried to overwrite the value of a struct field with a literal
for the purposes of a test and was surprised to find that the struct compared
the same before and after the assignment.

This functionality therefore seems useful at least for tests, but is probably
also useful for actual analysis of code.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D152813

Files:
  clang/lib/Analysis/FlowSensitive/Transfer.cpp
  clang/unittests/Analysis/FlowSensitive/TransferTest.cpp


Index: clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
@@ -811,6 +811,31 @@
       });
 }
 
+TEST(TransferTest, BinaryOperatorAssignLiteral) {
+  std::string Code = R"(
+    void target() {
+      int Foo = 1;
+      // [[before]]
+      Foo = 2;
+      // [[after]]
+    }
+  )";
+  runDataflow(
+      Code,
+      [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results,
+         ASTContext &ASTCtx) {
+        const Environment &Before =
+            getEnvironmentAtAnnotation(Results, "before");
+        const Environment &After = getEnvironmentAtAnnotation(Results, "after");
+
+        const auto &ValBefore =
+            getValueForDecl<IntegerValue>(ASTCtx, Before, "Foo");
+        const auto &ValAfter =
+            getValueForDecl<IntegerValue>(ASTCtx, After, "Foo");
+        EXPECT_NE(&ValBefore, &ValAfter);
+      });
+}
+
 TEST(TransferTest, VarDeclInitAssign) {
   std::string Code = R"(
     void target() {
Index: clang/lib/Analysis/FlowSensitive/Transfer.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/Transfer.cpp
+++ clang/lib/Analysis/FlowSensitive/Transfer.cpp
@@ -775,6 +775,11 @@
     Env.setValueStrict(*S, Env.getBoolLiteralValue(S->getValue()));
   }
 
+  void VisitIntegerLiteral(const IntegerLiteral *S) {
+    if (Value *Val = Env.createValue(S->getType()))
+      Env.setValueStrict(*S, *Val);
+  }
+
   void VisitParenExpr(const ParenExpr *S) {
     // The CFG does not contain `ParenExpr` as top-level statements in basic
     // blocks, however manual traversal to sub-expressions may encounter them.


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