[LifetimeSafety] Ignore parentheses when tracking expressions

[usx95]

Add support for handling parenthesized expressions in lifetime safety analysis.

Modified the OriginManager::get method to ignore parentheses when retrieving origins by recursively calling itself on the unparenthesized expression. This ensures that expressions with extra parentheses are properly analyzed for lifetime safety issues.

[usx95]

• [LifetimeSafety] Ignore parentheses when tracking expressions #167245 👈 (View in Graphite)
• [LifetimeSafety] Add support for conditional operators #167240
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[llvmbot]

@llvm/pr-subscribers-clang
@llvm/pr-subscribers-clang-temporal-safety

@llvm/pr-subscribers-clang-analysis

Author: Utkarsh Saxena (usx95)

Changes

Add support for handling parenthesized expressions in lifetime safety analysis.

Modified the OriginManager::get method to ignore parentheses when retrieving origins by recursively calling itself on the unparenthesized expression. This ensures that expressions with extra parentheses are properly analyzed for lifetime safety issues.

---

Full diff: https://github.com/llvm/llvm-project/pull/167245.diff

3 Files Affected:

• (modified) clang/lib/Analysis/LifetimeSafety/Origins.cpp (+2)
• (modified) clang/test/Sema/warn-lifetime-safety.cpp (+24)
• (modified) clang/unittests/Analysis/LifetimeSafetyTest.cpp (+17)

diff --git a/clang/lib/Analysis/LifetimeSafety/Origins.cpp b/clang/lib/Analysis/LifetimeSafety/Origins.cpp
index ea51a75324e06..0f2eaa94a5987 100644
--- a/clang/lib/Analysis/LifetimeSafety/Origins.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/Origins.cpp
@@ -34,6 +34,8 @@ Origin &OriginManager::addOrigin(OriginID ID, const clang::Expr &E) {
 
 // TODO: Mark this method as const once we remove the call to getOrCreate.
 OriginID OriginManager::get(const Expr &E) {
+  if (auto *ParenIgnored = E.IgnoreParens(); ParenIgnored != &E)
+    return get(*ParenIgnored);
   auto It = ExprToOriginID.find(&E);
   if (It != ExprToOriginID.end())
     return It->second;
diff --git a/clang/test/Sema/warn-lifetime-safety.cpp b/clang/test/Sema/warn-lifetime-safety.cpp
index 3057ac9385736..52165c4236988 100644
--- a/clang/test/Sema/warn-lifetime-safety.cpp
+++ b/clang/test/Sema/warn-lifetime-safety.cpp
@@ -635,3 +635,27 @@ void conditional_operator(bool cond) {
   }  // expected-note 4 {{destroyed here}}
   (void)*p;  // expected-note 4 {{later used here}}
 }
+
+void parentheses(bool cond) {
+  MyObj* p;
+  {
+    MyObj a;
+    p = &((((a))));  // expected-warning {{object whose reference is captured does not live long enough}}
+  }                  // expected-note {{destroyed here}}
+  (void)*p;          // expected-note {{later used here}}
+
+  {
+    MyObj a;
+    p = ((GetPointer((a))));  // expected-warning {{object whose reference is captured does not live long enough}}
+  }                           // expected-note {{destroyed here}}
+  (void)*p;                   // expected-note {{later used here}}
+
+  {
+    MyObj a, b, c, d;
+    p = &(cond ? cond ? a     // expected-warning {{object whose reference is captured does not live long enough}}.
+                      : b     // expected-warning {{object whose reference is captured does not live long enough}}.
+               : cond ? c     // expected-warning {{object whose reference is captured does not live long enough}}.
+                      : d);   // expected-warning {{object whose reference is captured does not live long enough}}.
+  }  // expected-note 4 {{destroyed here}}
+  (void)*p;  // expected-note 4 {{later used here}}
+}
diff --git a/clang/unittests/Analysis/LifetimeSafetyTest.cpp b/clang/unittests/Analysis/LifetimeSafetyTest.cpp
index 9d61d56e078e3..601308c53f9a9 100644
--- a/clang/unittests/Analysis/LifetimeSafetyTest.cpp
+++ b/clang/unittests/Analysis/LifetimeSafetyTest.cpp
@@ -700,6 +700,23 @@ TEST_F(LifetimeAnalysisTest, GslPointerInConditionalOperator) {
   EXPECT_THAT(Origin("v"), HasLoansTo({"a", "b"}, "p1"));
 }
 
+TEST_F(LifetimeAnalysisTest, ExtraParenthesis) {
+  SetupTest(R"(
+    void target() {
+      MyObj a;
+      View x = ((View((((a))))));
+      View y = ((View{(((x)))}));
+      View z = ((View(((y)))));
+      View p = ((View{((x))}));
+      POINT(p1);
+    }
+  )");
+  EXPECT_THAT(Origin("x"), HasLoansTo({"a"}, "p1"));
+  EXPECT_THAT(Origin("y"), HasLoansTo({"a"}, "p1"));
+  EXPECT_THAT(Origin("z"), HasLoansTo({"a"}, "p1"));
+  EXPECT_THAT(Origin("p"), HasLoansTo({"a"}, "p1"));
+}
+
 // FIXME: Handle temporaries.
 TEST_F(LifetimeAnalysisTest, ViewFromTemporary) {
   SetupTest(R"(