Reapply "[clang][dataflow] Model conditional operator correctly." with fixes (#89596)

I reverted https://github.com/llvm/llvm-project/pull/89213 beause it was
causing buildbots to fail with assertion failures.

Embarrassingly, it turns out I had been running tests locally in
`Release` mode, i.e. with `assert()` compiled away.

This PR re-lands #89213 with fixes for the failing assertions.

1 files changed, 63 insertions, 5 deletions

diff --git a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
index bb16138..215e208 100644
--- a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
+++ b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
@@ -3637,7 +3637,7 @@ TEST(TransferTest, VarDeclInitAssignConditionalOperator) {
     };
 
     void target(A Foo, A Bar, bool Cond) {
-      A Baz = Cond ?  Foo : Bar;
+      A Baz = Cond ?  A(Foo) : A(Bar);
       // Make sure A::i is modeled.
       Baz.i;
       /*[[p]]*/
@@ -5275,6 +5275,67 @@ TEST(TransferTest, BinaryOperatorComma) {
       });
 }
 
+TEST(TransferTest, ConditionalOperatorValue) {
+  std::string Code = R"(
+    void target(bool Cond, bool B1, bool B2) {
+      bool JoinSame = Cond ? B1 : B1;
+      bool JoinDifferent = Cond ? B1 : B2;
+      // [[p]]
+    }
+  )";
+  runDataflow(
+      Code,
+      [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results,
+         ASTContext &ASTCtx) {
+        Environment Env = getEnvironmentAtAnnotation(Results, "p").fork();
+
+        auto &B1 = getValueForDecl<BoolValue>(ASTCtx, Env, "B1");
+        auto &B2 = getValueForDecl<BoolValue>(ASTCtx, Env, "B2");
+        auto &JoinSame = getValueForDecl<BoolValue>(ASTCtx, Env, "JoinSame");
+        auto &JoinDifferent =
+            getValueForDecl<BoolValue>(ASTCtx, Env, "JoinDifferent");
+
+        EXPECT_EQ(&JoinSame, &B1);
+
+        const Formula &JoinDifferentEqB1 =
+            Env.arena().makeEquals(JoinDifferent.formula(), B1.formula());
+        EXPECT_TRUE(Env.allows(JoinDifferentEqB1));
+        EXPECT_FALSE(Env.proves(JoinDifferentEqB1));
+
+        const Formula &JoinDifferentEqB2 =
+            Env.arena().makeEquals(JoinDifferent.formula(), B2.formula());
+        EXPECT_TRUE(Env.allows(JoinDifferentEqB2));
+        EXPECT_FALSE(Env.proves(JoinDifferentEqB1));
+      });
+}
+
+TEST(TransferTest, ConditionalOperatorLocation) {
+  std::string Code = R"(
+    void target(bool Cond, int I1, int I2) {
+      int &JoinSame = Cond ? I1 : I1;
+      int &JoinDifferent = Cond ? I1 : I2;
+      // [[p]]
+    }
+  )";
+  runDataflow(
+      Code,
+      [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results,
+         ASTContext &ASTCtx) {
+        Environment Env = getEnvironmentAtAnnotation(Results, "p").fork();
+
+        StorageLocation &I1 = getLocForDecl(ASTCtx, Env, "I1");
+        StorageLocation &I2 = getLocForDecl(ASTCtx, Env, "I2");
+        StorageLocation &JoinSame = getLocForDecl(ASTCtx, Env, "JoinSame");
+        StorageLocation &JoinDifferent =
+            getLocForDecl(ASTCtx, Env, "JoinDifferent");
+
+        EXPECT_EQ(&JoinSame, &I1);
+
+        EXPECT_NE(&JoinDifferent, &I1);
+        EXPECT_NE(&JoinDifferent, &I2);
+      });
+}
+
 TEST(TransferTest, IfStmtBranchExtendsFlowCondition) {
   std::string Code = R"(
     void target(bool Foo) {
@@ -5522,10 +5583,7 @@ TEST(TransferTest, ContextSensitiveReturnReferenceWithConditionalOperator) {
         auto *Loc = Env.getReturnStorageLocation();
         EXPECT_THAT(Loc, NotNull());
 
-        // TODO: We would really like to make this stronger assertion, but that
-        // doesn't work because we don't propagate values correctly through
-        // the conditional operator yet.
-        // EXPECT_EQ(Loc, SLoc);
+        EXPECT_EQ(Loc, SLoc);
       },
       {BuiltinOptions{ContextSensitiveOptions{}}});
 }