[PATCH] D126972: [clang][dataflow] Modify optional-checker to handle type aliases.

[Yitzhak Mandelbaum via Phabricator via cfe-commits]

ymandel created this revision.
ymandel added reviewers: xazax.hun, sgatev.
Herald added subscribers: tschuett, steakhal, jeroen.dobbelaere, rnkovacs.
Herald added a project: All.
ymandel requested review of this revision.
Herald added a project: clang.

Previously, type aliases were not handled (and resulted in an assertion
firing). This patch generalizes the code to consider aliases everywhere (a
previous patch already considered aliases for optional-returning functions).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126972

Files:
  clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
  clang/unittests/Analysis/FlowSensitive/UncheckedOptionalAccessModelTest.cpp


Index: clang/unittests/Analysis/FlowSensitive/UncheckedOptionalAccessModelTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/UncheckedOptionalAccessModelTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/UncheckedOptionalAccessModelTest.cpp
@@ -2214,6 +2214,23 @@
       UnorderedElementsAre(Pair("check-4", "unsafe: input.cc:10:7")));
 }
 
+// Verifies that the check sees through aliases.
+TEST_P(UncheckedOptionalAccessTest, WithAlias) {
+  ExpectLatticeChecksFor(
+      R"(
+    #include "unchecked_optional_access_test.h"
+
+    template <typename T>
+    using MyOptional = $ns::$optional<T>;
+
+    void target(MyOptional<int> opt) {
+      opt.value();
+      /*[[check]]*/
+    }
+  )",
+      UnorderedElementsAre(Pair("check", "unsafe: input.cc:8:7")));
+}
+
 // FIXME: Add support for:
 // - constructors (copy, move)
 // - assignment operators (default, copy, move)
Index: clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
+++ clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
@@ -43,13 +43,14 @@
       hasTemplateArgument(0, refersToType(type().bind("T"))));
 }
 
-auto hasOptionalType() { return hasType(optionalClass()); }
-
-auto hasOptionalOrAliasType() {
+auto optionalOrAliasType() {
   return hasUnqualifiedDesugaredType(
       recordType(hasDeclaration(optionalClass())));
 }
 
+/// Matches any of the spellings of the optional types and sugar, aliases, etc.
+auto hasOptionalType() { return hasType(optionalOrAliasType()); }
+
 auto isOptionalMemberCallWithName(
     llvm::StringRef MemberName,
     llvm::Optional<StatementMatcher> Ignorable = llvm::None) {
@@ -164,9 +165,8 @@
 }
 
 auto isCallReturningOptional() {
-  return callExpr(callee(functionDecl(
-      returns(anyOf(hasOptionalOrAliasType(),
-                    referenceType(pointee(hasOptionalOrAliasType())))))));
+  return callExpr(callee(functionDecl(returns(anyOf(
+      optionalOrAliasType(), referenceType(pointee(optionalOrAliasType())))))));
 }
 
 /// Creates a symbolic value for an `optional` value using `HasValueVal` as the
@@ -485,8 +485,9 @@
   return MatchSwitchBuilder<LatticeTransferState>()
       // Attach a symbolic "has_value" state to optional values that we see for
       // the first time.
-      .CaseOf<Expr>(expr(anyOf(declRefExpr(), memberExpr()), hasOptionalType()),
-                    initializeOptionalReference)
+      .CaseOf<Expr>(
+          expr(anyOf(declRefExpr(), memberExpr()), hasOptionalType()),
+          initializeOptionalReference)
 
       // make_optional
       .CaseOf<CallExpr>(isMakeOptionalCall(), transferMakeOptionalCall)


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