[PATCH] D116272: [Clang][Sema] Avoid crashing for va_arg expressions with bool argument

Egor Zhdan via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Fri Dec 24 13:20:48 PST 2021

egorzhdan created this revision.
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This change fixes a compiler crash that was introduced in https://reviews.llvm.org/D103611: `Sema::BuildVAArgExpr` attempted to retrieve a corresponding signed type for `bool` by calling `ASTContext::getCorrespondingSignedType`.


  rG LLVM Github Monorepo



Index: clang/test/SemaCXX/varargs.cpp
--- clang/test/SemaCXX/varargs.cpp
+++ clang/test/SemaCXX/varargs.cpp
@@ -53,6 +53,8 @@
   // Ensure that signed vs unsigned doesn't matter either.
   (void)__builtin_va_arg(ap, unsigned int);
+  (void)__builtin_va_arg(ap, bool); // expected-warning {{second argument to 'va_arg' is of promotable type 'bool'; this va_arg has undefined behavior because arguments will be promoted to 'int'}}
 #if __cplusplus >= 201103L
Index: clang/lib/Sema/SemaExpr.cpp
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -15913,7 +15913,7 @@
       // promoted type and the underlying type are the same except for
       // signedness. Ask the AST for the correctly corresponding type and see
       // if that's compatible.
-      if (!PromoteType.isNull() &&
+      if (!PromoteType.isNull() && !UnderlyingType->isBooleanType() &&
           PromoteType->isUnsignedIntegerType() !=
               UnderlyingType->isUnsignedIntegerType()) {
         UnderlyingType =

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