[clang] c033f0d - [Clang][Sema] Avoid crashing for va_arg expressions with bool argument

[Jan Svoboda via cfe-commits]

Author: Egor Zhdan
Date: 2022-01-07T10:41:45+01:00
New Revision: c033f0d9b1c7816b0488a939475d48a100e4dcab

URL: https://github.com/llvm/llvm-project/commit/c033f0d9b1c7816b0488a939475d48a100e4dcab
DIFF: https://github.com/llvm/llvm-project/commit/c033f0d9b1c7816b0488a939475d48a100e4dcab.diff

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

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`.

rdar://86580370

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D116272

Added: 
    

Modified: 
    clang/lib/Sema/SemaExpr.cpp
    clang/test/SemaCXX/varargs.cpp

Removed: 
    


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diff  --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index d454e4877bcef..a2a1f76df96d2 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -15946,7 +15946,7 @@ ExprResult Sema::BuildVAArgExpr(SourceLocation BuiltinLoc,
       // 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 =

diff  --git a/clang/test/SemaCXX/varargs.cpp b/clang/test/SemaCXX/varargs.cpp
index 7bec2f1e63030..bc2fe89a6ff8d 100644
--- a/clang/test/SemaCXX/varargs.cpp
+++ b/clang/test/SemaCXX/varargs.cpp
@@ -53,6 +53,8 @@ void promotable(int a, ...) {
 
   // 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