[PATCH] D99274: [analyzer] Fix crash when reasoning about C11 atomics (PR49422)

[Valeriy Savchenko via Phabricator via cfe-commits]

vsavchenko created this revision.
vsavchenko added reviewers: NoQ, steakhal, xazax.hun, ASDenysPetrov.
Herald added subscribers: Charusso, dkrupp, donat.nagy, Szelethus, jfb, 
mikhail.ramalho, a.sidorin, rnkovacs, szepet, baloghadamsoftware.
vsavchenko requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

rdar://75020762


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D99274

Files:
  clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
  clang/test/Analysis/atomics.c


Index: clang/test/Analysis/atomics.c
===================================================================
--- clang/test/Analysis/atomics.c
+++ clang/test/Analysis/atomics.c
@@ -93,3 +93,11 @@
   clang_analyzer_eval(s->refCount == 3); // expected-warning {{UNKNOWN}}
   clang_analyzer_eval(expected == 2); // expected-warning {{UNKNOWN}}
 }
+
+// PR49422
+void test_atomic_compare(int input) {
+  _Atomic(int) x = input;
+  if (x > 0) {
+    // no crash
+  }
+}
Index: clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
===================================================================
--- clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
+++ clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
@@ -139,6 +139,12 @@
 
   /// Returns the type of the APSInt used to store values of the given 
QualType.
   APSIntType getAPSIntType(QualType T) const {
+    // For the purposes of the analysis and constraints, we treat atomics
+    // as their underlying types.
+    if (const AtomicType *AT = T->getAs<AtomicType>()) {
+      T = AT->getValueType();
+    }
+
     assert(T->isIntegralOrEnumerationType() || Loc::isLocType(T));
     return APSIntType(Ctx.getIntWidth(T),
                       !T->isSignedIntegerOrEnumerationType());



Index: clang/test/Analysis/atomics.c
===================================================================
--- clang/test/Analysis/atomics.c
+++ clang/test/Analysis/atomics.c
@@ -93,3 +93,11 @@
   clang_analyzer_eval(s->refCount == 3); // expected-warning {{UNKNOWN}}
   clang_analyzer_eval(expected == 2); // expected-warning {{UNKNOWN}}
 }
+
+// PR49422
+void test_atomic_compare(int input) {
+  _Atomic(int) x = input;
+  if (x > 0) {
+    // no crash
+  }
+}
Index: clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
===================================================================
--- clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
+++ clang/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
@@ -139,6 +139,12 @@
 
   /// Returns the type of the APSInt used to store values of the given QualType.
   APSIntType getAPSIntType(QualType T) const {
+    // For the purposes of the analysis and constraints, we treat atomics
+    // as their underlying types.
+    if (const AtomicType *AT = T->getAs<AtomicType>()) {
+      T = AT->getValueType();
+    }
+
     assert(T->isIntegralOrEnumerationType() || Loc::isLocType(T));
     return APSIntType(Ctx.getIntWidth(T),
                       !T->isSignedIntegerOrEnumerationType());

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