Add a workaround for a libstdc++-4.2 <tr1/hashtable> bug. This header uses
return false;
in a function returning a pointer. 'false' was a null pointer constant in C++98
but is not in C++11. Punch a very small hole in the initialization rules in
C++11 mode to allow this specific case in system headers.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184395 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 4e55da3..9d7fcda 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -4135,6 +4135,24 @@
}
}
+/// An egregious hack for compatibility with libstdc++-4.2: in <tr1/hashtable>,
+/// a function with a pointer return type contains a 'return false;' statement.
+/// In C++11, 'false' is not a null pointer, so this breaks the build of any
+/// code using that header.
+///
+/// Work around this by treating 'return false;' as zero-initializing the result
+/// if it's used in a pointer-returning function in a system header.
+static bool isLibstdcxxPointerReturnFalseHack(Sema &S,
+ const InitializedEntity &Entity,
+ const Expr *Init) {
+ return S.getLangOpts().CPlusPlus11 &&
+ Entity.getKind() == InitializedEntity::EK_Result &&
+ Entity.getType()->isPointerType() &&
+ isa<CXXBoolLiteralExpr>(Init) &&
+ !cast<CXXBoolLiteralExpr>(Init)->getValue() &&
+ S.getSourceManager().isInSystemHeader(Init->getExprLoc());
+}
+
/// The non-zero enum values here are indexes into diagnostic alternatives.
enum InvalidICRKind { IIK_okay, IIK_nonlocal, IIK_nonscalar };
@@ -4571,9 +4589,11 @@
AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
} else if (ICS.isBad()) {
DeclAccessPair dap;
- if (Initializer->getType() == Context.OverloadTy &&
- !S.ResolveAddressOfOverloadedFunction(Initializer
- , DestType, false, dap))
+ if (isLibstdcxxPointerReturnFalseHack(S, Entity, Initializer)) {
+ AddZeroInitializationStep(Entity.getType());
+ } else if (Initializer->getType() == Context.OverloadTy &&
+ !S.ResolveAddressOfOverloadedFunction(Initializer, DestType,
+ false, dap))
SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
else
SetFailed(InitializationSequence::FK_ConversionFailed);