[clang] 94d6dd0 - [AST] Fix an undefine behavior when creating an empty recovery expr.

[Haojian Wu via cfe-commits]

Author: Haojian Wu
Date: 2020-04-16T12:35:45+02:00
New Revision: 94d6dd01ba439ffcef7f7873622cf6ae99bcf5cb

URL: https://github.com/llvm/llvm-project/commit/94d6dd01ba439ffcef7f7873622cf6ae99bcf5cb
DIFF: https://github.com/llvm/llvm-project/commit/94d6dd01ba439ffcef7f7873622cf6ae99bcf5cb.diff

LOG: [AST] Fix an undefine behavior when creating an empty recovery expr.

Summary:
We forgot to initialize the NumExpr member in one of the constructors,
which leads crashes in preamble serialization.

Reviewers: sammccall

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78284

Added: 
    clang/test/PCH/cxx-recovery-expr.cpp

Modified: 
    clang/include/clang/AST/Expr.h
    clang/lib/AST/Expr.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index fab84f6a6ecd..4d89234b0da7 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -6080,7 +6080,8 @@ class RecoveryExpr final : public Expr,
 private:
   RecoveryExpr(ASTContext &Ctx, SourceLocation BeginLoc, SourceLocation EndLoc,
                ArrayRef<Expr *> SubExprs);
-  RecoveryExpr(EmptyShell Empty) : Expr(RecoveryExprClass, Empty) {}
+  RecoveryExpr(EmptyShell Empty, unsigned NumSubExprs)
+      : Expr(RecoveryExprClass, Empty), NumExprs(NumSubExprs) {}
 
   size_t numTrailingObjects(OverloadToken<Stmt *>) const { return NumExprs; }
 

diff  --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index bc6fadc71609..f108b49ceac1 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -4652,7 +4652,7 @@ RecoveryExpr *RecoveryExpr::Create(ASTContext &Ctx, SourceLocation BeginLoc,
 RecoveryExpr *RecoveryExpr::CreateEmpty(ASTContext &Ctx, unsigned NumSubExprs) {
   void *Mem = Ctx.Allocate(totalSizeToAlloc<Expr *>(NumSubExprs),
                            alignof(RecoveryExpr));
-  return new (Mem) RecoveryExpr(EmptyShell());
+  return new (Mem) RecoveryExpr(EmptyShell(), NumSubExprs);
 }
 
 void OMPArrayShapingExpr::setDimensions(ArrayRef<Expr *> Dims) {

diff  --git a/clang/test/PCH/cxx-recovery-expr.cpp b/clang/test/PCH/cxx-recovery-expr.cpp
new file mode 100644
index 000000000000..e0d58c119c54
--- /dev/null
+++ b/clang/test/PCH/cxx-recovery-expr.cpp
@@ -0,0 +1,13 @@
+// Test with pch.
+// RUN: %clang_cc1 -emit-pch -frecovery-ast -fallow-pch-with-compiler-errors -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fno-validate-pch -emit-llvm -o - %s
+
+#ifndef HEADER
+#define HEADER
+
+int func(int);
+int s = func();
+
+#else
+
+#endif