Implementing C99 partial re-initialization behavior (DR-253)
Based on previous discussion on the mailing list, clang currently lacks support
for C99 partial re-initialization behavior:
Reference: http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-April/029188.html
Reference: http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_253.htm
This patch attempts to fix this problem.
Given the following code snippet,
struct P1 { char x[6]; };
struct LP1 { struct P1 p1; };
struct LP1 l = { .p1 = { "foo" }, .p1.x[2] = 'x' };
// this example is adapted from the example for "struct fred x[]" in DR-253;
// currently clang produces in l: { "\0\0x" },
// whereas gcc 4.8 produces { "fox" };
// with this fix, clang will also produce: { "fox" };
Differential Review: http://reviews.llvm.org/D5789
llvm-svn: 239446
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 8b1bc69..883b76b 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -160,10 +160,12 @@
EmitAggLoadOfLValue(E);
}
+ void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E);
void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
void VisitChooseExpr(const ChooseExpr *CE);
void VisitInitListExpr(InitListExpr *E);
void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
+ void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing.
void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
Visit(DAE->getExpr());
}
@@ -1056,6 +1058,9 @@
return;
} else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
return EmitNullInitializationToLValue(LV);
+ } else if (isa<NoInitExpr>(E)) {
+ // Do nothing.
+ return;
} else if (type->isReferenceType()) {
RValue RV = CGF.EmitReferenceBindingToExpr(E);
return CGF.EmitStoreThroughLValue(RV, LV);
@@ -1276,6 +1281,15 @@
cleanupDominator->eraseFromParent();
}
+void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
+ AggValueSlot Dest = EnsureSlot(E->getType());
+
+ LValue DestLV = CGF.MakeAddrLValue(Dest.getAddr(), E->getType(),
+ Dest.getAlignment());
+ EmitInitializationToLValue(E->getBase(), DestLV);
+ VisitInitListExpr(E->getUpdater());
+}
+
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