ricejasonf created this revision.
ricejasonf added a reviewer: aaron.ballman.
ricejasonf added a project: clang.
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The structured bindings decomposition of a non-dependent array in a dependent
context (a template) were, upon instantiation, creating nested OpaqueValueExprs
that would trigger assertions in CodeGen. Additionally the OpaqueValuesExpr's
contained SourceExpr is being emitted in CodeGen, but there was no code for its
transform in template instantiation. This would trigger other assertions such
as when emitting a DeclRefExpr that refers to a VarDecl that is not marked as
ODR-used.
This is all based on cursory deduction, but with the way the code flows from
SemaTemplateInstantiate back to SemaInit, it is apparent that the nesting of
OpaqueValueExpr is unintentional.
This commit fixes https://bugs.llvm.org/show_bug.cgi?id=45964 and possible
other issues involving OpaqueValueExprs in template instantiations might be
resolved.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D108482
Files:
clang/lib/Sema/SemaInit.cpp
clang/lib/Sema/TreeTransform.h
Index: clang/lib/Sema/TreeTransform.h
===================================================================
--- clang/lib/Sema/TreeTransform.h
+++ clang/lib/Sema/TreeTransform.h
@@ -10511,7 +10511,19 @@
TreeTransform<Derived>::TransformOpaqueValueExpr(OpaqueValueExpr *E) {
assert((!E->getSourceExpr() ||
getDerived().AlreadyTransformed(E->getType())) &&
"opaque value expression requires transformation");
- return E;
+
+ // Note that SourceExpr can be nullptr
+ ExprResult SourceExpr = TransformExpr(E->getSourceExpr());
+ if (SourceExpr.isInvalid()) return ExprError();
+ if (SourceExpr.get() == E->getSourceExpr() && !getDerived().AlwaysRebuild())
{
+ return E;
+ }
+
+ OpaqueValueExpr *New =
+ new (SemaRef.Context) OpaqueValueExpr(E->getExprLoc(), E->getType(),
+ E->getValueKind(),
E->getObjectKind(),
+ SourceExpr.get());
+ return New;
}
template<typename Derived>
Index: clang/lib/Sema/SemaInit.cpp
===================================================================
--- clang/lib/Sema/SemaInit.cpp
+++ clang/lib/Sema/SemaInit.cpp
@@ -8643,9 +8643,13 @@
case SK_ArrayLoopIndex: {
Expr *Cur = CurInit.get();
- Expr *BaseExpr = new (S.Context)
- OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
- Cur->getValueKind(), Cur->getObjectKind(), Cur);
+ // prevent nested OpaqueValueExprs
+ Expr *BaseExpr = dyn_cast<OpaqueValueExpr>(Cur);
+ if (!BaseExpr) {
+ BaseExpr = new (S.Context)
+ OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
+ Cur->getValueKind(), Cur->getObjectKind(), Cur);
+ }
Expr *IndexExpr =
new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
CurInit = S.CreateBuiltinArraySubscriptExpr(
Index: clang/lib/Sema/TreeTransform.h
===================================================================
--- clang/lib/Sema/TreeTransform.h
+++ clang/lib/Sema/TreeTransform.h
@@ -10511,7 +10511,19 @@
TreeTransform<Derived>::TransformOpaqueValueExpr(OpaqueValueExpr *E) {
assert((!E->getSourceExpr() || getDerived().AlreadyTransformed(E->getType())) &&
"opaque value expression requires transformation");
- return E;
+
+ // Note that SourceExpr can be nullptr
+ ExprResult SourceExpr = TransformExpr(E->getSourceExpr());
+ if (SourceExpr.isInvalid()) return ExprError();
+ if (SourceExpr.get() == E->getSourceExpr() && !getDerived().AlwaysRebuild()) {
+ return E;
+ }
+
+ OpaqueValueExpr *New =
+ new (SemaRef.Context) OpaqueValueExpr(E->getExprLoc(), E->getType(),
+ E->getValueKind(), E->getObjectKind(),
+ SourceExpr.get());
+ return New;
}
template<typename Derived>
Index: clang/lib/Sema/SemaInit.cpp
===================================================================
--- clang/lib/Sema/SemaInit.cpp
+++ clang/lib/Sema/SemaInit.cpp
@@ -8643,9 +8643,13 @@
case SK_ArrayLoopIndex: {
Expr *Cur = CurInit.get();
- Expr *BaseExpr = new (S.Context)
- OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
- Cur->getValueKind(), Cur->getObjectKind(), Cur);
+ // prevent nested OpaqueValueExprs
+ Expr *BaseExpr = dyn_cast<OpaqueValueExpr>(Cur);
+ if (!BaseExpr) {
+ BaseExpr = new (S.Context)
+ OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
+ Cur->getValueKind(), Cur->getObjectKind(), Cur);
+ }
Expr *IndexExpr =
new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
CurInit = S.CreateBuiltinArraySubscriptExpr(
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