erik.pilkington created this revision.
erik.pilkington added reviewers: rjmccall, rsmith.
Herald added subscribers: dexonsmith, jkorous.
Herald added a project: clang.
`MarkVarDeclODRUsed` indirectly calls `captureInBlock`, which creates a copy
expression. The copy expression is insulated in it's own
`ExpressionEvaluationContext`, so it saves, mutates, and restores
`MaybeODRUseExprs` as `CleanupVarDeclMarking` is iterating through it, leading
to a crash. Fix this by iterating through a local copy of `MaybeODRUseExprs`.
rdar://47493525
Repository:
rC Clang
https://reviews.llvm.org/D59670
Files:
clang/include/clang/Sema/Sema.h
clang/lib/Sema/SemaExpr.cpp
clang/test/SemaCXX/blocks.cpp
Index: clang/test/SemaCXX/blocks.cpp
===================================================================
--- clang/test/SemaCXX/blocks.cpp
+++ clang/test/SemaCXX/blocks.cpp
@@ -145,3 +145,11 @@
A::foo(); });
}
}
+
+namespace test7 {
+struct S {};
+void f() {
+ constexpr S s;
+ auto some_block = ^{ (void)s; };
+}
+}
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -15686,7 +15686,12 @@
}
void Sema::CleanupVarDeclMarking() {
- for (Expr *E : MaybeODRUseExprs) {
+ // Iterate through a local copy in case MarkVarDeclODRUsed makes a recursive
+ // call.
+ MaybeODRUseExprSet LocalMaybeODRUseExprs;
+ std::swap(LocalMaybeODRUseExprs, MaybeODRUseExprs);
+
+ for (Expr *E : LocalMaybeODRUseExprs) {
VarDecl *Var;
SourceLocation Loc;
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
@@ -15702,8 +15707,6 @@
MarkVarDeclODRUsed(Var, Loc, *this,
/*MaxFunctionScopeIndex Pointer*/ nullptr);
}
-
- MaybeODRUseExprs.clear();
}
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -587,13 +587,13 @@
/// element type here is ExprWithCleanups::Object.
SmallVector<BlockDecl*, 8> ExprCleanupObjects;
- /// Store a list of either DeclRefExprs or MemberExprs
- /// that contain a reference to a variable (constant) that may or may not
- /// be odr-used in this Expr, and we won't know until all lvalue-to-rvalue
- /// and discarded value conversions have been applied to all subexpressions
- /// of the enclosing full expression. This is cleared at the end of each
- /// full expression.
- llvm::SmallPtrSet<Expr*, 2> MaybeODRUseExprs;
+ /// Store a set of either DeclRefExprs or MemberExprs that contain a
reference
+ /// to a variable (constant) that may or may not be odr-used in this Expr,
and
+ /// we won't know until all lvalue-to-rvalue and discarded value conversions
+ /// have been applied to all subexpressions of the enclosing full expression.
+ /// This is cleared at the end of each full expression.
+ using MaybeODRUseExprSet = llvm::SmallPtrSet<Expr *, 2>;
+ MaybeODRUseExprSet MaybeODRUseExprs;
std::unique_ptr<sema::FunctionScopeInfo> PreallocatedFunctionScope;
@@ -1029,7 +1029,7 @@
/// context (i.e. the number of TypoExprs created).
unsigned NumTypos;
- llvm::SmallPtrSet<Expr*, 2> SavedMaybeODRUseExprs;
+ MaybeODRUseExprSet SavedMaybeODRUseExprs;
/// The lambdas that are present within this context, if it
/// is indeed an unevaluated context.
Index: clang/test/SemaCXX/blocks.cpp
===================================================================
--- clang/test/SemaCXX/blocks.cpp
+++ clang/test/SemaCXX/blocks.cpp
@@ -145,3 +145,11 @@
A::foo(); });
}
}
+
+namespace test7 {
+struct S {};
+void f() {
+ constexpr S s;
+ auto some_block = ^{ (void)s; };
+}
+}
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -15686,7 +15686,12 @@
}
void Sema::CleanupVarDeclMarking() {
- for (Expr *E : MaybeODRUseExprs) {
+ // Iterate through a local copy in case MarkVarDeclODRUsed makes a recursive
+ // call.
+ MaybeODRUseExprSet LocalMaybeODRUseExprs;
+ std::swap(LocalMaybeODRUseExprs, MaybeODRUseExprs);
+
+ for (Expr *E : LocalMaybeODRUseExprs) {
VarDecl *Var;
SourceLocation Loc;
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
@@ -15702,8 +15707,6 @@
MarkVarDeclODRUsed(Var, Loc, *this,
/*MaxFunctionScopeIndex Pointer*/ nullptr);
}
-
- MaybeODRUseExprs.clear();
}
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -587,13 +587,13 @@
/// element type here is ExprWithCleanups::Object.
SmallVector<BlockDecl*, 8> ExprCleanupObjects;
- /// Store a list of either DeclRefExprs or MemberExprs
- /// that contain a reference to a variable (constant) that may or may not
- /// be odr-used in this Expr, and we won't know until all lvalue-to-rvalue
- /// and discarded value conversions have been applied to all subexpressions
- /// of the enclosing full expression. This is cleared at the end of each
- /// full expression.
- llvm::SmallPtrSet<Expr*, 2> MaybeODRUseExprs;
+ /// Store a set of either DeclRefExprs or MemberExprs that contain a reference
+ /// to a variable (constant) that may or may not be odr-used in this Expr, and
+ /// we won't know until all lvalue-to-rvalue and discarded value conversions
+ /// have been applied to all subexpressions of the enclosing full expression.
+ /// This is cleared at the end of each full expression.
+ using MaybeODRUseExprSet = llvm::SmallPtrSet<Expr *, 2>;
+ MaybeODRUseExprSet MaybeODRUseExprs;
std::unique_ptr<sema::FunctionScopeInfo> PreallocatedFunctionScope;
@@ -1029,7 +1029,7 @@
/// context (i.e. the number of TypoExprs created).
unsigned NumTypos;
- llvm::SmallPtrSet<Expr*, 2> SavedMaybeODRUseExprs;
+ MaybeODRUseExprSet SavedMaybeODRUseExprs;
/// The lambdas that are present within this context, if it
/// is indeed an unevaluated context.
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